US20090097781A1

US20090097781A1 - Airtight storage bag

Info

Publication number: US20090097781A1
Application number: US11/871,563
Authority: US
Inventors: Luen-Sing TANG
Original assignee: SHUN SHING POLYETHYLENE PRINTING CO Ltd
Current assignee: SHUN SHING POLYETHYLENE PRINTING CO Ltd
Priority date: 2007-10-12
Filing date: 2007-10-12
Publication date: 2009-04-16

Abstract

An airtight storage bag is defined by at least one plastic film formed into a pouch. The pouch has a containment region with an openable mouth. There are a first resealable zone extending across the openable mouth to allow closure of the month, and a second resealable zone also extending across the mouth and located on the containment region side of the first resealable zone to allow airtight closure of the containment region. A vent is located between the first and second resealable zones to allow displacement of fluid from the containment region via the vent. The second resealable zone when sealed seals the containment region from the exterior of the bag.

Description

FIELD OF INVENTION

The present invention relates to an air tight bag, and also its use and related methods. In particular, though not solely, it relates to an airtight bag that allows venting of gases from inside the package prior to airtight sealing of the bag. In particular, although not solely, the invention relates to a package useful for storing food or other items from which a user can at least partially evacuate gases with minimal or no equipment required for evacuating the gases.

BACKGROUND ART

Packages suitable for storing items in an air tight environment are known.
The benefits of storing an item in an environment where no further air or gases enter, or are predominantly prevented from entering, include prolonged life for perishable items, or reduction in mildew, moulds, take-up of bad odours or exclusion of insects and moisture for perishable items and non-perishable items alike.
Another application of such air tight storage is the use of an air tight storage bag for holding items in a compressed state when air is removed from the package. Such bags can be used for space saving storage of items that are compressible, for example blankets, linen and clothes.
Typically when such packages are used the user locates the contents into the package and then uses some form of mechanical device, for example a vacuum cleaner, hand pump or other device able to create a vacuum to remove at least some of the atmosphere in the package. The package is then sealed and the contents are contained in a reduced atmosphere environment. The use of such packages in this manner therefore requires the vacuum creating equipment to be present.
When the vacuum creating equipment runs on an electrical supply this requires the presence of a supply of electricity. This may prevent use of such equipment where no supply of electricity is present, or is awkward to provide.
Regardless of whether an electrically powered device or a non-electrically powered device, for example a hand pump, is used, the user must first have this equipment. Secondly they must use it each time they wish to store items in such a bag. This may be inconvenient for a user, for example if they are travelling.
Regardless of whether or not the user is using an additional device or not, when air or gas has been removed to the required level the user must then attempt to seal the package. For packages that have a large opening through which the contents is located into the pouch this can be difficult as the user must close and seal the pouch before the air or gas rushes back in.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is therefore an object of the present invention to provide an airtight bag that allows air tight storage of items in the bag that uses reduced levels of equipment over the prior art, or makes it easier for a user to evacuate and seal such a bag, or that at least goes some way to overcoming the disadvantages of the prior art, or at least provides the public with a useful choice. It is a further object of the present invention to provide a method of manufacture and also use of such a bag.

BRIEF DESCRIPTION

In a first aspect the present invention may be said to broadly consist in an airtight storage bag defined by at least one plastic film formed into a pouch that defines a containment region with an openable mouth, said bag further comprising,
a first resealable zone extending completely across said openable mouth, to allow closure of said openable mouth,
a second resealable zone extending completely across said openable mouth, adjacent to and located on the containment region side of said first resealable zone, to allow airtight closure of the containment region, and
a vent located between said first and second resealable zones, to allow displacement of fluid from said containment region via said vent, at least when said first resealable zone is sealed,
wherein said second resealable zone when sealed seals the containment region from the exterior of said bag.
Preferably said second resealable zone is adjacent to said first resealable zone.
Preferably said vent is closer to said first resealable zone than said second resealable zone.
Preferably at or near said openable mouth two opposed wall of the pouch are defined by the at least one plastic film and the vent exists at one of said walls.
Preferably said openable mouth opens upwards.
Preferably at or near said openable mouth two opposed wall of the pouch are defined by the at least one plastic film and a vent exists at both of said walls.
Preferably said vent consists of at least one aperture through said plastic film, to allow passage therethrough of fluid from said containment region.
Preferably said first resealable zone and second resealable zone is established by any one or more of,
a reclosable profile strip
an adhesive band (with or without a peelable backing layer), and
a foldable region.
Preferably said pouch is defined by,
(a) one folded sheet of plastics film to define two overlying plies that are sealed along non-folded edges save for said openable mouth to define side edges of said pouch, or
(a) two overlying sheets of plastics film, sealed along all free edges save for the openable mouth to define side edges and a bottom edge of said pouch.
Preferably said plastics film is a multi-ply plastics film, at least one of said sheets of multi-ply plastics film being of at least two plies laminated to or with each other, namely an interior-most ply and an exterior-most ply.
Preferably sealing of said edges is done by heat or ultrasonic sealing.
Preferably said walls are provided by two rectangular sheets of said multi-ply plastics film, to define side edges, a bottom edge and said openable mouth, wherein said rectangular sheets are sealed to one another at said side edges and said bottom edge.
Preferably said walls are provided by a rectangular sheet of said multi-ply plastics film, folded longitudinally to define side edges, a bottom edge and said openable mouth, wherein said rectangular sheet is sealed to itself at said side edges and said bottom edge.
Preferably sealing of said edges is done by heat or ultrasonic sealing.
Preferably said vent consists of at least one internal aperture through the interior-most ply of said at least two plies and at least one external aperture through the exterior-most ply of said at least two plies, said internal aperture and said external aperture being in fluid communication with each other.
Alternatively said vent consists of at least one internal aperture through the interior-most ply of said at least two plies and a gas permeable exterior-most ply of said at least two plies, said interior aperture and said exterior-most ply being in fluid communication with each other.
Alternatively said vent consists of a gas permeable interior-most ply of said at least two plies and at least one external aperture through the exterior-most ply of said at least two plies, said interior-most ply and said external aperture being in fluid communication with each other.
Preferably said interior-most ply at a region intermediate of said first and second resealable zones, includes,
(a) at least one intermediate strip having two opposite edges and that extends from at least one of the side edges of the pouch, and
(b) at least two other strips each with edges immediately adjacent to respectively each of the opposite edges of the at least one intermediate strip,
wherein the at least one intermediate strip is of a material that is not sealable or is sealable to a lesser extent as compared to the at least two other strips so that at said seal of at least one of said side edges of said pouch and where said intermediate strip is located, an opening to the exterior of the pouch may be created for said vent to allow passage therethrough of fluid from said containment region.
Preferably said interior-most ply is of substantially uniform thickness.
Preferably said exterior-most ply is a nylon material and said at least one intermediate strip is an oriented polypropylene (OPP) and said at least two other strips are a cast polypropylene (CPP).
In a further aspect the present invention consists in an airtight storage bag comprising or including,
a plastics pouch having an interior and an exterior with an openable mouth definable between two opposed walls of said plastics pouch,
a first resealable zone extending completely across said openable mouth,
a second resealable zone extending completely across said openable mouth, interiorly of said first resealable zone, and
a vent, located between said first and second resealable zones, to vent from the interior of said plastics pouch, at least when said first resealable zone is sealed, to said exterior,
wherein after content is located in said plastics pouch said first resealable zone is sealed creation of an interior pressure higher than an exterior pressure of the plastics pouch in the vicinity of said vent causes gas in the interior of said plastics pouch to expel to said exterior via said vent, and thereafter said second resealable zone can be sealed to seal said openable mouth and thus seal in the content of said plastics pouch.
Preferably said second resealable zone is adjacent to said first resealable zone.
Preferably said vent is closer to said first resealable zone than said second resealable zone.
Preferably at said openable mouth two opposed wall of the pouch are defined by the at least one plastic film and the vent exists at one of said walls.
Preferably at said openable mouth two opposed wall of the pouch are defined by the at least one plastic film and a vent exists at both of said walls.
Preferably said vent consists of at least one aperture through said plastic film, to allow passage therethrough of fluid from said containment region.
Preferably said first resealable zone and second resealable zone is established by any one or more of,
a reclosable profile strip
an adhesive band (with or without a peelable backing layer), and
a foldable region.
Preferably said pouch is defined by,
(a) one folded sheet of plastics film to define two overlying plies that are sealed along non-folded edges save for said openable mouth to define side edges of said pouch, or
(b) two overlying sheets of plastics film, sealed along all free edges save for the openable mouth to define side edges and a bottom edge of said pouch.
Preferably said plastics film is a multi-ply plastics film, at least one of said sheets of multi-ply plastics film being of at least two plies laminated to or with each other, namely an interior-most ply and an exterior-most ply.
Preferably sealing of said edges is done by heat or ultrasonic sealing.
Preferably said walls are provided by two rectangular sheets of said multi-ply plastics film, to define side edges, a bottom edge and said openable mouth, wherein said rectangular sheets are sealed to one another at said side edges and said bottom edge.
Preferably said walls are provided by a rectangular sheet of said multi-ply plastics film, folded longitudinally to define side edges, a bottom edge and said openable mouth, wherein said rectangular sheet is sealed to itself at said side edges and said bottom edge.
Preferably sealing of said edges is done by heat or ultrasonic sealing.
Preferably said vent consists of at least one internal aperture through an interior-most ply of said at least two plies and at least one external aperture through the exterior-most ply of said at least two plies, said internal aperture and said external aperture being in fluid communication with each other.
Alternatively said vent consists of at least one internal aperture through the interior-most ply of said at least two plies and a gas permeable exterior-most ply of said at least two plies, said interior aperture and said exterior-most ply being in fluid communication with each other.
Alternatively said vent consists of a gas permeable interior-most ply of said at least two plies and at least one external aperture through the exterior-most ply of said at least two plies, said interior-most ply and said external aperture being in fluid communication with each other.
Preferably said interior-most ply at a region intermediate of said first and second resealable zones, includes,
(a) at least one intermediate strip having two opposite edges and that extends from at least one of the side edges of the pouch, and
(b) at least two other strips each with edges immediately adjacent to respectively each of the opposite edges of the at least one intermediate strip,
wherein the at least one intermediate strip is of a material that is not sealable or is sealable to a lesser extent as compared to the at least two other strips so that at said seal of at least one of said side edges of said pouch and where said intermediate strip is located, an opening to the exterior of the pouch may be created for said vent to allow passage therethrough of fluid from said containment region.
Preferably said interior-most ply is of substantially uniform thickness.
Preferably said exterior-most ply is a nylon material and said at least one intermediate strip is an oriented polypropylene (OPP) and said at least two other strips are a cast polypropylene (CPP).
In a further aspect still the present invention consists in a method of use of an airtight storage bag having a plastics pouch having an interior and an exterior with an openable mouth definable between two opposed walls of said plastics pouch, comprising or including the steps of
(i) opening said airtight storage bag and locating content in the interior via said openable mouth,
(ii) sealing a first resealable zone that extends completely across said openable mouth,
(iii) creating an interior pressure higher than an exterior pressure of the plastics pouch in the vicinity of a vent to cause gas in the interior of said plastics pouch to expel to said exterior via said vent,
(iv) thereafter sealing a second resealable zone that extends completely across said openable mouth located interior of said vent on at least one said wall, to seal in the content of said airtight storage bag.
Preferably said second resealable zone is adjacent to said first resealable zone.
Preferably said vent is closer to said first resealable zone than said second resealable zone.
Preferably at or near said openable mouth two opposed wall of the pouch are defined by the at least one plastic film and the vent exists at one of said walls.
Preferably at or near said openable mouth two opposed wall of the pouch are defined by the at least one plastic film and a vent exists at both of said walls.
Preferably said vent consists of at least one aperture through said plastic film, to allow passage therethrough of fluid from said containment region.
Preferably said first resealable zone and second resealable zone is established by any one or more of,
a reclosable profile strip
an adhesive band (with or without a peelable backing layer), and
a foldable region.
Preferably said pouch is defined by,
(a) one folded sheet of plastics film to define two overlying plies that are sealed along non-folded edges save for said openable mouth to define side edges of said pouch, or
(b) two overlying sheets of plastics film, sealed along all free edges save for the openable mouth to define side edges and a bottom edge of said pouch.
Preferably said plastics film is a multi-ply plastics film, at least one of said sheets of multi-ply plastics film being of at least two plies laminated to or with each other, namely an interior-most ply, and an exterior-most ply.
Preferably sealing of said edges is done by heat or ultrasonic sealing.
Preferably said walls are provided by two rectangular sheets of said multi-ply plastics film, to define side edges, a bottom edge and said openable mouth, wherein said rectangular sheets are sealed to one another at said side edges and said bottom edge.
Preferably said walls are provided by a rectangular sheet of said multi-ply plastics film, folded longitudinally to define side edges, a bottom edge and said openable mouth, wherein said rectangular sheet is sealed to itself at said side edges and said bottom edge.
Preferably sealing of said edges is done by heat or ultrasonic sealing.
Preferably said vent consists of at least one internal aperture through an interior-most ply of said at least two plies and at least one external aperture through the exterior-most ply of said at least two plies, said internal aperture and said external aperture being in fluid communication with each other.
Alternatively said vent consists of at least one internal aperture through the interior-most ply of said at least two plies and a gas permeable exterior-most ply of said at least two plies, said interior aperture and said exterior-most ply being in fluid communication with each other.
Alternatively said vent consists of a gas permeable interior-most ply of said at least two plies and at least one external aperture through the exterior-most ply of said at least two plies, said interior-most ply and said external aperture being in fluid communication with each other.
Preferably said interior-most ply at a region intermediate of said first and second resealable zones, includes,
(a) at least one intermediate strip having two opposite edges and that extends from at least one of the side edges of the pouch, and
(b) at least two other strips each with edges immediately adjacent to respectively each of the opposite edges of the at least one intermediate strip,
wherein the at least one intermediate strip is of a material that is not sealable or is sealable to a lesser extent as compared to the at least two other strips so that at said seal of at least one of said side edges of said pouch and where said intermediate strip is located, an opening to the exterior of the pouch may be created for said vent to allow passage therethrough of fluid from said containment region.
Preferably said interior-most ply is of substantially uniform thickness.
Preferably said exterior-most ply is a nylon material and said at least one intermediate strip is an oriented polypropylene (OPP) and said at least two other strips are a cast polypropylene (CPP).
In a further aspect the present invention may be said to consist in an airtight storage bag defined by at least one multi-ply plastics film, having an interior most ply and an exterior-most ply laminated to or with said interior-most ply, formed into a pouch that defines a containment region with an openable mouth extending between side edges defined by heat sealing of the at least one multiply plastic film of the pouch, said bag further comprising,
a first resealable zone extending completely across said openable mouth, to allow closure of said openable mouth,
a second resealable zone extending completely across said openable mouth, adjacent to and located on the containment region side of said first resealable zone, to allow airtight closure of the containment region, and
a vent located between said first and second resealable zones, to allow displacement of fluid from said containment region via said vent, at least when said first resealable zone is sealed,
wherein said interior-most ply, at a region intermediate of said first and second resealable zones, includes
(a) at least one intermediate strip having two opposite edges and that extends from at least one of the side edges of the pouch, and
(b) at least two other strips each with edges immediately adjacent to respectively each of the opposite edges of the at least one intermediate strip,
wherein the at least one intermediate strip is of a material that is non-heat sealable or heat sealable to a lesser extent as compared to the at least two other strips so that at the at least one heat sealed side edge of said pouch and where said intermediate strip is located, an opening to the exterior of the pouch may be created for said vent
wherein said second resealable zone when sealed seals the containment region from the exterior of said bag.
Preferably said pouch is defined by,
(a) one folded sheet of plastics film to define two overlying layers of multi-ply plastics film that are sealed along non-folded edges save for said openable mouth, or
(b) two overlying sheets of multi-ply plastics film, sealed along all free edges save for the openable mouth.
Preferably said vent is closer to said first resealable zone than said second resealable zone.
Preferably said exterior-most ply is a nylon material and said at least one intermediate strip is an oriented polypropylene (OPP) and said at least two other strips are a cast polypropylene (CPP).
In a further aspect still the present invention consists in an airtight storage bag as herein described with reference to any one or more of the accompanying drawings.
In a further aspect still the present invention consists in a method of use an airtight storage bag as herein described with reference to any one or more of the accompanying drawings.
In a further aspect still the present invention consists in a method of manufacture of an airtight storage bag as herein described with reference to any one or more of the accompanying drawings.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

BRIEF DESCRIPTION OF DRAWINGS

Preferred forms of the present invention will now be described with reference to the accompanying drawings of which;

FIG. 1 shows in perspective view an air tight storage bag with the openable mouth in an upward orientation;

FIG. 2 shows the bag of FIG. 1 in side view showing the locations of the first resealable zone, vent and second resealable zone;

FIG. 3 shows certain corner detail of the preferred type of vent at the left hand side edge of one wall of the bag in perspective view;

FIG. 4 shows certain corner detail of the type of vent in FIG. 3 at the right hand side edge of one wall of the bag in perspective view;

FIG. 5 shows certain close up edge detail of the vent shown in FIG. 3 present on one wall of the air tight storage bag at (A) with the vent closed and at (B) with the vent open;

FIG. 6 shows certain close up edge detail of the vent shown in FIG. 4 present on both walls of the air tight storage bag at (A) with the vent closed and at (B) with the vent open;

FIG. 7 shows apparatus for one form of manufacture of the air tight storage bag of the present invention, the apparatus and plastics films are mirrored below also, to provide the second sheet to form the other wall of the pouch,

FIG. 8 shows in perspective view the location of content via the openable mouth in the interior of the air tight storage bag;

FIG. 9 shows in perspective view pressure being applied to the airtight bag after the first resealable zone is sealed, at (A) to expel the air inside the bag out via the preferred embodiment vents formed in the seals of the side edges, and at (B) to expel the air inside the bag out via the vents formed in walls of the bag;

FIG. 10 shows the bag and content of FIG. 9 after the air has been expelled and the second resealable zone is sealed to seal in the content;

FIG. 11 shows one way in which the bag of the present invention can be manufactured from two separate sheets of plastic film, as per the apparatus outlined in FIG. 7;

FIG. 12 shows another way in which the bag of the present invention can be manufactured from a single sheet of plastics film folded longitudinally to form a bottom edge and free side edges for later sealing;

FIG. 13 shows less preferred forms of vents formed by apertures in the walls of the bag at (A) a series of circular apertures, and at (B) a series of simple slits, it being understood that there could be many apertures as shown or only one;

FIG. 14 shows a cross-sectional view through a wall of the bag in the vent region, the wall in this case made from a multi-ply plastics film, where there the vent is an aperture on the interior-most ply and an aperture on the exterior-most ply, the two apertures mis-aligned but in fluid communication with each other;

FIG. 15 shows a vertical cross-section through a bag, showing the openable mouth, first resealable zone, vent (in this case the less preferred vent form of a simple aperture), second resealable zone, and bag interior, the plastics pouch forming the bag in this case could be blow moulded rather than by sealing edges of a folded sheet, or edges of two sheets;

FIG. 16 shows a roll of plastic film with the first and second resealable zones and vent in place, such as could be used in the apparatus shown in FIG. 17; and

FIG. 17 shows an apparatus for taking a web of plastics film, for example from a roll, putting a longitudinal fold in it and thereafter sealing the edges to make an airtight storage bag.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention shall now be described with reference to the FIGS. 1 through 17.
In the preferred form the present invention consists of an air tight storage bag (1). The airtight storage bag (1) may be quadrilateral (e.g. square or rectangular) in form or of any other form and is closed on all free sides or edges, save for the openable mouth (9), to form a pouch (2). For example it is sealed on the left hand side (7), the right hand side (8) and the bottom (6) when made from two sheets of plastics film forming the walls (5) of the pouch (2). In other embodiments it is sealed only on the sides when a rectangular plastics film is folded longitudinally to form the walls (5), so that the longitudinal fold (27) forms the bottom (6) of the airtight storage bag (1). The pouch (2) may consist of two walls (5 a) and (5 b).
The fourth side or top as shown in FIGS. 1 and 2 is open and presents as an openable mouth (9). In other embodiments there may be more than four sides and these may be sealed accordingly to still provide an openable mouth (9).
The interior (3) of the pouch is communicable to the exterior (4) via the openable mouth (9).
Toward the openable mouth (9) there is a first resealable zone (10). Located inward or interiorly of the first resealable zone (10) and preferably adjacent thereto is a vent (11). Located inward or interiorly again from the vent (11) and preferably adjacent thereto is a second resealable zone (12). The term interior here means further away from the free edge of the openable mouth (9), i.e. towards the interior of the bag, that is further down the walls of the pouch so that the first resealable zone (10) is to be closest to the free edge of the openable mouth, the vent (11) is the next most close, and the second sealable zone (12) is the third most close zone to the openable mouth (9) of the pouch (2). Both resealable zones are preferably of the same length so that when the bag is open either one does not provide any greater constriction (if any) to the mouth of the bag than the other. This allows for items to pass into and out of the bag without being restricted more by one of the other zones. The first and second resealable zones are preferably co-extensive with one another across the openable mouth.
In the preferred embodiment shown in FIGS. 1 and 2, the vent (11) is situated at the sealed edges of both the left side (7) and the right side (8). A variation is that the vent (11) is situated at the sealed edge of only one of the left and tight sides. Still further variation, in other embodiments as will be explained later, is that the vent (11) may be situated anywhere on the walls (5 a) and/or (5 b) of the bag. The key aspect is that the vent (11) is between the two resealable zones, in this case first resealable zone (10) and second resealable zone (12).
In the preferred embodiment the vent (11) is closer to the first resealable zone (10) than the second resealable zone (12) as this, as will be explained, helps to make re-entrance of air via the vent more difficult.
The first resealable zone (10) and second resealable zone (12) in the preferred embodiment extend all the way from the left hand side (7) to the right hand side (8) across the openable mouth (9). Therefore when the first resealable zone (10) is sealed the air tight storage bag (1) is only partially sealed due to the presence of the vent (11). The second resealable zone (12) when sealed completely seals the air tight storage bag (1).
The walls (5 a) and (5 b) in the preferred embodiment are made from a multi-ply plastics film wherein the various plies are preferably laminated together. In other embodiments the walls may be made from a single ply film. In the preferred embodiment the multi-ply plastic film consists of at least two plies, an interior most ply (15) and an exterior most ply (16) laminated to each other. In other embodiments of the present invention the walls (5 a) and (5 b) may consist of a multi-ply plastic film (13) of more than 2 plies, in which case the exterior most ply and the interior most ply are still laminated with each other, though with intermediate plies therebetween. The lamination is preferably done with heat and adhesives. A person skilled in the art will appreciate that the plastic film (13) making the walls (5 a) and (5 b) can be made from any method known in the art, such as extrusion, co-extrusion, and lamination or similar.
The walls (5 a) and (5 b) may be transparent or not. In the accompanying drawings, it is assumed that the walls are transparent, so that the first and second resealable zones (10) and (12), and the intermediate strip (25) which will be explained below and which can be colored, can be seen from the exterior of the bag as in the drawings even though otherwise they may only be seen from the interior of the bag.
The basic function of the vent (11) is to allow expelling of air or gas, through at least one or both of the walls (5 a) and (5 b) or sides (7) and (8) on which it is present, from the interior (3) to the exterior (4). There are several ways in which this vent (11) can be formed. The preferred form is that disclosed in the granted U.S. Pat. No. 6,582,123 of the present inventor, which is fully incorporated herein by reference. This utilises an at least two ply plastics film, wherein the interior-most ply is made of at least two dissimilar materials, one less sealable to itself and the other material than the other material.
One of the two dissimilar materials due to its material properties has a lower propensity to sealing or a higher sealing temperature to itself or the other dissimilar material. Thus when a seal is formed at a free edge to form a side (7) or (8) a less or no sealed portion is formed.
In the preferred embodiment as shown in FIGS. 1 to 6 (where the preferred vent is shown), the venting of gases occurs at the sealed edges of the sides (7) and (8). The walls (5 a) and (5 b) are preferably formed from the same plastic film (13) (whether of two sheets or of longitudinal folding) and are sealed to each other at the left and right sides and the bottom as shown in FIGS. 1 and 2. At the side edges, due to the non-sealable or less-sealable properties of the intermediate strip (25) present in the interior most ply (15) (explained below) as compared with the other strips (26) on either side thereof (explained below) in terms of sealing temperature and/or propensity to sealing, sealing of the interior most ply (15) with the opposed wall does not occur (or occurs less) at the locations where the intermediate strip (25) is present, though sealing of the interior most ply (15) with the opposed wall occurs at the locations where the intermediate strip (25) is absent. In other words, at the sealed regions of sides (7) and (8), there is no or less sealing between the interior most ply (15) and the opposed wall at the locations where the intermediate strip is present. Thus there is a non-sealed (or less-sealed) region (where the intermediate strip (25) is present) which operates as the vent (11) at each of the sealed side edges (7) and (8), and the sealed side edges (7) and (8) are actually partially sealed.
When a greater pressure is built up in the interior, the pressure up to some sufficient degree will cause the non-sealed or less-sealed regions at the side edges (7) and (8) to “open up” to allow the interior gases to escape (20). FIGS. 5A and 6A show the opened state of the preferred vent (11) through which the interior gases escape when the interior pressure is built up to a degree sufficient to “open up” the vent (11). Where there is no or little pressure difference between the interior and the exterior, the non-sealed or less-sealed region is in a substantially closed state (though not sealed) due to the urging effect of the neighboring plastics material urging the two walls to be pressed towards each other at the side regions (7) and (8) even at the non-sealed or less-sealed regions (i.e., the vent).
In other, less preferred ways the vent (11) may be a simple aperture through the wall or walls (5) on which it is present. Such aperture may be a small hole, series of holes, or a slit, or series of slits, or any other aperture. The key function as stated of the vent (11) is to allow gases to escape from the interior (3) to the exterior (4) when greater pressure is present in the interior (3) than at the exterior (4). In the preferred embodiment the rate of escape of gases through the vent is low (i.e. the apertures, slits, holes or partially-sealed regions are small).
In other embodiments the vent (11) may be across part of the openable mouth (9), or may be a series of holes or slit or series of slits over a portion of the wall (5).
In yet other less preferred embodiments of the present invention the vent (11) may consist of an aperture or apertures (21) on the interior most ply (15) of the multi-ply plastic sheet, and an external aperture on the exterior most ply (16). The two apertures internal and external, need not necessarily be aligned with each other provided they are fluidly communicatable with each other to allow air or gas (20) to be expelled. Therefore a labyrinthine path between internal aperture (17) and external aperture (18) may be present, particularly when the plastic film (13) consists of more than two plies.
In yet other embodiments the interior-most ply may be some form of gas permeable layer and the exterior most ply may have an aperture, alternatively the interior most ply may have an aperture and the exterior most ply may be a gas permeable layer, or the interior most ply and the exterior most ply may both be gas permeable over a particular region defining the vent (11).
The first and second resealable zones can be achieved with any number of ways known in the art to form an air tight seal. In the preferred form of the present invention the air tight seal is formed by a reclosable profile strip. The two portions of the reclosable profile strip each mounted to separate interior facing portions of the walls (5 a) and (5 b) so that when brought into proximity to each other the profile strip can close the openable mouth (9) of the air tight storage bag (1). In yet other embodiments of the present invention the first and second resealable zones 10 and (12) can be formed from an adhesive region, or any other form of closure that would seal wall (5 a) to the other wall (5 b). In yet other forms of the present invention the first resealable zone (10) can be closed by folding over of the region proximate to the first resealable zone so that the openable mouth is sealed. The second resealable zone (12) can be similarly closed.
The preferred method of use of the present invention will now be described.
The air tight storage bag (1) has the openable mouth (9) able to receive content (19) into the interior (3) of the pouch (2). Once content (19) is located then the first resealable zone (10) is sealed thus closing the openable mouth (9) and partially sealing the airtight storage bag (1). The user can then create a higher internal pressure in the interior (3) of the air tight storage bag (1) than on the exterior (4). Such pressure differential can be created simply by pressing on the walls (5) of the air tight storage bag (1) by the user's hands (22) to create an internal pressure therein.
Alternatively equipment to produce such pressure differential can be used. For example equipment that will produce a lower pressure at least in the vicinity of the vent (11).
However in the preferred embodiment it is simply the application of pressure to the exterior (4) surfaces of the bag (1) that produces the pressure differential to expel gases in the interior (3) of the air tight storage bag (1) out via the vent (11). Once the desired reduction in internal volume or gas is achieved the second resealable zone (12) is closed to seal the vent (11) from the exterior (4). Because the vent (11) is small in comparison to the volume of the bag the flow of air back into the bag is very slow and so overall the increase in air in the bag whilst the second resealable zone is resealed is minimal.
In this way the content (19) is thus sealed in the interior (3) of the air tight storage bag (1). The content (19) can range from food stuffs that need sealing in an air tight environment to compressible materials such as, but not limited to, clothing, linen and the like, that can be reduced in volume by expelling air around them. In this way the air tight storage bag can be used for storing food and also in another embodiment can be used as a space saving bag.
To remove the contents (19) from the air tight storage bag (1) the first and second resealable zones (10) and (12) respectively are opened and the contents (19) removed from the interior (3) of the pouch (2). The air tight storage bag can be reused or can be a recyclable item and/or discarded after single use.
The method of manufacture and construction of the air tight storage bag will now be described.
The preferred method of manufacture utilises sealing of free edges (24). This can be achieved either by sealing free edges (24) of two separate sheets of plastic film, or of one sheet of plastics film folded longitudinally save for the free edge that defines the openable mouth (9).
This will define an air tight storage bag with two opposed walls that defines the openable mouth, the airtight storage bag having sealed left hand (7) and right hand (8) sealed side edges and a bottom (6). The bottom (6) is defined by sealing in the case of two separate sheets of plastics film, or the longitudinal fold in the case of a single sheet of plastics film folded longitudinally.
The vent (11) and the first and second resealable zones can be provided in the airtight storage bag in a number of ways.
The plastics film (13) may come in a roll (28) form with the first and second resealable zones located on that surface that will form the interior-most surface of the bag. The vent, in the less preferred way may be provided as an aperture or a series of apertures already in place through at least one wall (5) of the bag, or may be punctured into place in one of the steps of manufacturing the bag. The vent may also be present in a separate plastics strip laminated or joined to strips either side to define the plastics film (13). The most preferred form will be described shortly.
The first and second resealable zone can be formed from any one or more of, a reclosable profile strip (complementary components of the strip being each on facing surfaces of the interior-most ply (15)), and adhesive band (with or without a peelable backing layer), or the resealable zone may be a foldable region to form the seal.
In a preferred method of manufacture the plastics film is a multiply film manufactured in a way disclosed in U.S. Pat. No. 6,582,123 which is fully incorporated herein by reference. The first and second resealable zones may be added to this multi-ply film as part of the manufacture of the plastics film (e.g. as a roll), or may be added immediately prior to manufacture of the bag. In either such method it will be important that the first and second resealable zones are located one on either side of the intermediate strip (25). The intermediate strip is of a material that is less sealable than the materials that form the at least two other strips (26) either side. Less sealable, or non-sealable, in the present context means that the intermediate strip (25) needs a higher temperature to seal or has a lower propensity to seal with the opposed wall than the two other strips (26) on either side. Sealing (heat sealing) of the left hand (7) and right hand (8) sides will therefore form a vent out the side seals due to this lowered ability to seal of the intermediate strip (25) with the opposed wall.
When two walls (either as two separate sheets, or as one sheet folded longitudinally) are brought parallel to each other then the free edges can be sealed. As stated preferably before this step the components that comprise the first and second resealable zones (10) and (12) are also introduced (or may be present on the web of plastics film already). In the preferred embodiment these materials for forming the resealable zones are introduced to or are present on the interior facing surfaces of the two separate or one longitudinally folded plastics film(s).
The components for providing the first and second resealable zones are laminated, attached, adhered or otherwise located to the interior facing surfaces of the plastics film (13).
Once the resealable zone components are attached to the interior surface(s) of the two plastics film (13) then edge sealing can be used to form the left hand side (7) and right hand side (8) sealed edges. In the case of two separate plastics film sheets, sealing to produce a bottom (6) is also required.
In the preferred embodiment such sealing is formed by heat sealing in the known manner. Alternatively these seals can be formed by ultrasonic welding, or possibly adhesives.
The air tight storage bag (1) can then be cut from the line of formed air tight storage bags to form individual air tight storage bags (1). Alternatively it may have a severable portion between adjacent air tight storage bags that allows an air tight storage bag (1) to be torn off a roll or web and used when desired.
Detailed construction of the preferred form of the preferred vent form is shown in FIGS. 3 through 6 showing the left and right hand sides' construction of the vent (11). The intermediate strip (25) is shown on the inner most ply (15). The exterior most ply (16) is shown also and is laminated with the interior most ply. A person skilled in the art will understand that there may be other plies therebetween. In the preferred embodiment the exterior most ply (16) is formed from a nylon based material or, less preferably oriented polypropylene (OPP). The interior most ply (15) is formed from a polypropylene material. As described in the preferred embodiment the interior-most ply (15) is a composite of strips of differing material properties. There is an intermediate strip (25) in between two other strips (26). In the preferred form, the edges of the intermediate strip (15) abut the respective edges of the other strips (26), and the thickness of the interior most ply (15) is uniform or substantially uniform.
The intermediate strip (25) is made from an oriented polypropylene (OPP) and the other strips (26) are made from a cast polypropylene (CPP) in the preferred embodiment. The CPP material can be heat sealed to each other at a temperature of substantially 130° Celsius or more. However at temperatures of less than 180° the OPP material will not seal to itself or to the CPP material.
The melt point of these two material (when heat sealing is used) is different (with the intermediate strip being higher) so that when sealing between opposed walls occurs when forming the sides edges (7) and (8) there is less or no sealing at the location where the intermediate strip (25) is present (i.e., the intermediate strip does not seal or seal less with the adjacent ply of the opposed wall). Thus there is a vent formed from the interior of the bag to the exterior via the unsealed (or less sealed) intermediate strip (25) at the side edge(s).
In the preferred embodiment, the location of the vent (11) being closer to the first resealable zone (10) than to the second resealable zone (12) urges the vent to stay closed after air has been expelled.
Cross sections through the vent (11) are shown in FIGS. 5 and 6 for two different embodiments. The walls (5 a) and (5 b) are shown manufactured from plastic film (13) that is multi-ply. The exterior most ply (16) of the multi-ply film (13) is manufactured as stated in the preferred embodiment from a nylon based material. The interior most ply (15) is manufactured from polypropylene material and is laminated to the exterior most ply. The intermediate strip (25) giving rise to the vent (11) as a result of the differential sealing properties at the bag's side edges of the intermediate strip (25) and the other strips (26) forming the interior most ply is shown as being only on one wall (5 b) in FIG. 5. There, in the preferred embodiment, the intermediate strip (25) is of OPP while the other strips (26) are of CPP. The interior most ply of the opposed wall (5 a) is also of CPP.
FIG. 6 shows a similar cross sectional view to that of FIG. 5 with the exception that both walls (5 a) and (5 b) have an intermediate strip (25) thereon forming the vent (11) in a similar manner. There, both walls (5 a) and (5 b) are formed from the same plastic film (13), and both has an intermediate strip (25) with two other trips (26) on either side forming the interior most ply (15). The intermediate strips (25) are of OPP while the other strips (26) are of CPP. Sealing at the side edges between the two walls (5 a) and (5 b) occurs between the respective interior most plies (15) of the two walls (5 a) and (5 b), except for the region where the intermediate strips (25) are present and facing each other due to the non-sealable or less-sealable properties of the intermediate strip (25) as compared with the other strips (26).
The effect the preferred form of vent has is shown in FIGS. 5B and 6B. Namely, in the preferred embodiment, air is expelled from the containment region of the bag into the vent (11) at the side edge(s) where the intermediate strip (25) is present in one or both of the walls (5 a) and (5 b), the vent (11) being formed due to the less or no heat sealing between the intermediate strip (25) and the adjacent ply in the opposed wall at the side edge(s), and the vent (11) being opened due to the differential pressure between the interior (3) and the exterior (4). The gas or air (20) being expelled passes through the vent (11) to the exterior.
In all embodiments, since nylon is comparatively less permeable to air, nylon is preferably present in the plastic film (13) whether as the most exterior ply or otherwise.
The normal method of manufacture uses two webs of plastics film (or single web if folding longitudinally) off rolls (or roll) to pass through a forming machine (28) with the components to form the resealable zones, in the machine direction (MD). Heat sealing then occurs transverse to the machine direction (MD) at the free edges to form the side edges and parallel to the machine direction (MD) to form the bottom edge (optional on single sheet longitudinal folding).
In other embodiments the air tight plastics bag may be formed from a single sack of plastic, such as that which may be formed by blow moulding with the addition of the resealable zones and vent.
The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention as defined by the accompanying claims.

Claims

1. An airtight storage bag defined by at least one plastic film formed into a pouch that defines a containment region with an openable mouth, said bag further comprising,

a first resealable zone extending completely across said openable mouth, to allow closure of said openable mouth,

a second resealable zone extending completely across said openable mouth, located on the containment region side of said first resealable zone, to allow airtight closure of the containment region, and

a vent located between said first and second resealable zones, to allow displacement of fluid from said containment region via said vent, at least when said first resealable zone is sealed,

wherein said second resealable zone when sealed seals the containment region from the exterior of said bag.

2. An airtight storage bag as claimed in claim 1 wherein said vent is closer to said first resealable zone than said second resealable zone.

3. An airtight storage bag as claimed in claim 1 wherein said pouch is defined by,

(a) one folded sheet of plastics film to define two overlying plies that are sealed along non-folded edges, except for said openable mouth, to define side edges of said pouch, or

(b) two overlying sheets of plastics film, sealed along all free edges, except for the openable mouth, to define side edges and a bottom edge of said pouch.

4. An airtight storage bag as claimed in claim 3 wherein at least one of said sheets of plastics film is a multi-ply plastics film, said multi-ply plastics film being of at least two plies laminated to or with each other, namely an interior-most ply and an exterior-most ply.

5. An airtight storage bag as claimed in claim 3 wherein sealing of said edges is done by heat or ultrasonic sealing.

6. An airtight storage bag as claimed in claim 4 wherein said interior-most ply at a region intermediate of said first and second resealable zones, includes,

(a) at least one intermediate strip having two opposite edges and that extends from at least one of the side edges of the pouch, and

(b) at least two other strips each with edges immediately adjacent to respectively each of the opposite edges of the at least one intermediate strip,

wherein the at least one intermediate strip is of a material that is not sealable or is sealable to a lesser extent as compared to the at least two other strips so that at said seal of at least one of said side edges of said pouch and where said intermediate strip is located, an opening to the exterior of the pouch may be created for said vent to allow passage therethrough of fluid from said containment region.

7. An airtight storage bag as claimed in claim 6 wherein said exterior-most ply is a nylon material and said at least one intermediate strip is an oriented polypropylene (OPP) and said at least two other strips are a cast polypropylene (CPP).

8. An airtight storage bag as claimed in claim 4 wherein said vent consists of at least one internal aperture through the interior-most ply of said at least two plies and at least one external aperture through the exterior-most ply of said at least two plies, said internal aperture and said external aperture being in fluid communication with each other.

9. An airtight storage bag as claimed in claim 1 wherein at or near said openable mouth two opposed walls of the pouch are defined by the at least one plastic film and said vent exists at one or both of said walls.

10. An airtight storage bag as claimed in claim 1 wherein said vent consists of at least one aperture through said plastic film, to allow passage therethrough of fluid from said containment region.

11. An airtight storage bag as claimed in claim 1 wherein said first resealable zone and second resealable zone is established by any one or more of

(a) a reclosable profile strip,

(b) an adhesive band (with or without a peelable backing layer), and

(c) a foldable region.

12. An airtight storage bag comprising or including,

a plastics pouch having an interior and an exterior with an openable mouth definable between two opposed walls of said plastics pouch,

a first resealable zone extending completely across said openable mouth,

a second resealable zone extending completely across said openable mouth, interiorly of said first resealable zone, and

a vent, located between said first and second resealable zones, to vent from the interior of said plastics pouch, at least when said first resealable zone is sealed, to said exterior,

wherein after content is located in said plastics pouch and said first resealable zone is sealed, creation of an interior pressure higher than an exterior pressure of the plastics pouch in the vicinity of said vent causes gas in the interior of said plastics pouch to expel to said exterior via said vent, and thereafter said second resealable zone can be sealed to seal said openable mouth and thus seal in the content of said plastics pouch.

13. An airtight storage bag as claimed in claim 12 wherein said vent consists of at least one aperture through said plastic film, to allow passage therethrough of fluid from said containment region.

14. An airtight storage bag as claimed in claim 12 wherein said first resealable zone and second resealable zone is established by any one or more of,

(a) a reclosable profile strip

(b) an adhesive band (with or without a peelable backing layer), and

(c) a foldable region.

15. An airtight storage bag as claimed in claim 12 wherein said pouch is defined by,

(b) two overlying sheets of plastics film, sealed along all free edges, except for the openable mouth, to define side edges and a bottom edge.

16. An airtight storage bag as claimed in claim 15 wherein at least one of said sheets of plastics film is a multi-ply plastics film, said multi-ply plastics film being of at least two plies laminated to or with each other, namely an interior-most ply and an exterior-most ply.

17. An airtight storage bag as claimed in claim 16 wherein said interior-most ply at a region intermediate of said first and second resealable zones, includes,

(a) at least one intermediate strip having two opposite edges and that extends from at least one of said side edges of said pouch, and

wherein the at least one intermediate strip is of a material that is non sealable or is sealable to a lesser extent as compared to the at least two other strips so that at said seal of at least one of said side edges of said pouch and where said intermediate strip is located, an opening to the exterior of the pouch may be created for said vent to allow passage therethrough of fluid from said containment region.

18. An airtight storage bag as claimed in claim 17 wherein said exterior-most ply is a nylon material and said at least one intermediate strip is an oriented polypropylene (OPP) and said at least two other strips are a cast polypropylene (CPP).

19. A method of use of an airtight storage bag having a plastics pouch that has an interior and an exterior with an openable mouth definable between two opposed walls of said plastics pouch, comprising or including the steps of

(i) opening said airtight storage bag and locating content in the interior via said openable mouth,

(ii) sealing a first resealable zone that extends completely across said openable mouth,

(iii) creating an interior pressure higher than an exterior pressure of the plastics pouch in the vicinity of a vent to cause gas in the interior of said plastics pouch to expel to said exterior via said vent,

(iv) thereafter sealing a second resealable zone that extends completely across said openable mouth located interior of said vent on at least one said walls, to seal in the content of said airtight storage bag.

20. A method as claimed in claim 19 wherein said vent consists of at least one aperture through said plastic film, to allow passage therethrough of fluid from said containment region.

21. A method as claimed in claim 19 wherein said first resealable zone and second resealable zone is established by any one or more of,

(a) a reclosable profile strip

(b) an adhesive band (with or without a peelable backing layer), and

(c) a foldable region.

22. A method as claimed in claim 19 wherein said pouch is defined by,

23. A method as claimed in claim 22 wherein at least one of said sheets of plastics film is a multi-ply plastics film, said multi-ply plastics film being of at least two plies laminated to or with each other, namely an interior-most ply and an exterior-most ply.

24. A method as claimed in claim 23 wherein said interior-most ply at a region intermediate of said first and second resealable zones, includes,

25. An airtight storage bag defined by at least one multi-ply plastics film having an interior most ply and an exterior-most ply laminated to or with said interior most ply and formed into a pouch that defines a containment region with an openable mouth extending between side edges defined by heat sealing of the at least one multiply plastic film of the pouch, said bag further comprising,

a second resealable zone extending completely across said openable mouth, adjacent to and located on the containment region side of said first resealable zone, to allow airtight closure of the containment region, and

wherein said interior-most ply, at a region intermediate of said first and second resealable zones, includes

wherein the at least one intermediate strip is of a material that is non-heat sealable or heat sealable to a lesser extent as compared to the at least two other strips so that at the at least one heat sealed side edge of said pouch and where said intermediate strip is located, an opening to the exterior of the pouch may be created for said vent,