U.S. patent application number 11/871563 was filed with the patent office on 2009-04-16 for airtight storage bag.
Invention is credited to Luen-Sing TANG.
Application Number | 20090097781 11/871563 |
Document ID | / |
Family ID | 40534285 |
Filed Date | 2009-04-16 |
United States Patent
Application |
20090097781 |
Kind Code |
A1 |
TANG; Luen-Sing |
April 16, 2009 |
AIRTIGHT STORAGE BAG
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.
Inventors: |
TANG; Luen-Sing; (Hong Kong,
HK) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
US
|
Family ID: |
40534285 |
Appl. No.: |
11/871563 |
Filed: |
October 12, 2007 |
Current U.S.
Class: |
383/61.2 ;
383/61.1 |
Current CPC
Class: |
B65D 81/2023 20130101;
B65D 85/18 20130101; B65D 2205/02 20130101; B65D 33/2566
20130101 |
Class at
Publication: |
383/61.2 ;
383/61.1 |
International
Class: |
B65D 33/16 20060101
B65D033/16; B65D 33/18 20060101 B65D033/18; B65D 33/24 20060101
B65D033/24 |
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, (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.
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 (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
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, (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.
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, (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.
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
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.
Description
FIELD OF INVENTION
[0001] 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
[0002] Packages suitable for storing items in an air tight
environment are known.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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
[0011] 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,
[0012] a first resealable zone extending completely across said
openable mouth, to allow closure of said openable mouth,
[0013] 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
[0014] 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,
[0015] wherein said second resealable zone when sealed seals the
containment region from the exterior of said bag.
[0016] Preferably said second resealable zone is adjacent to said
first resealable zone.
[0017] Preferably said vent is closer to said first resealable zone
than said second resealable zone.
[0018] 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.
[0019] Preferably said openable mouth opens upwards.
[0020] 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.
[0021] Preferably said vent consists of at least one aperture
through said plastic film, to allow passage therethrough of fluid
from said containment region.
[0022] Preferably said first resealable zone and second resealable
zone is established by any one or more of,
[0023] a reclosable profile strip
[0024] an adhesive band (with or without a peelable backing layer),
and
[0025] a foldable region.
[0026] Preferably said pouch is defined by,
[0027] (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
[0028] (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.
[0029] 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.
[0030] Preferably sealing of said edges is done by heat or
ultrasonic sealing.
[0031] 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.
[0032] 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.
[0033] Preferably sealing of said edges is done by heat or
ultrasonic sealing.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] Preferably said interior-most ply at a region intermediate
of said first and second resealable zones, includes,
[0038] (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
[0039] (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,
[0040] 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.
[0041] Preferably said interior-most ply is of substantially
uniform thickness.
[0042] 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).
[0043] In a further aspect the present invention consists in an
airtight storage bag comprising or including,
[0044] a plastics pouch having an interior and an exterior with an
openable mouth definable between two opposed walls of said plastics
pouch,
[0045] a first resealable zone extending completely across said
openable mouth,
[0046] a second resealable zone extending completely across said
openable mouth, interiorly of said first resealable zone, and
[0047] 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,
[0048] 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.
[0049] Preferably said second resealable zone is adjacent to said
first resealable zone.
[0050] Preferably said vent is closer to said first resealable zone
than said second resealable zone.
[0051] 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.
[0052] 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.
[0053] Preferably said vent consists of at least one aperture
through said plastic film, to allow passage therethrough of fluid
from said containment region.
[0054] Preferably said first resealable zone and second resealable
zone is established by any one or more of,
[0055] a reclosable profile strip
[0056] an adhesive band (with or without a peelable backing layer),
and
[0057] a foldable region.
[0058] Preferably said pouch is defined by,
[0059] (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
[0060] (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.
[0061] 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.
[0062] Preferably sealing of said edges is done by heat or
ultrasonic sealing.
[0063] 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.
[0064] 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.
[0065] Preferably sealing of said edges is done by heat or
ultrasonic sealing.
[0066] 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.
[0067] 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.
[0068] 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.
[0069] Preferably said interior-most ply at a region intermediate
of said first and second resealable zones, includes,
[0070] (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
[0071] (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,
[0072] 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.
[0073] Preferably said interior-most ply is of substantially
uniform thickness.
[0074] 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).
[0075] 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
[0076] (i) opening said airtight storage bag and locating content
in the interior via said openable mouth,
[0077] (ii) sealing a first resealable zone that extends completely
across said openable mouth,
[0078] (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,
[0079] (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.
[0080] Preferably said second resealable zone is adjacent to said
first resealable zone.
[0081] Preferably said vent is closer to said first resealable zone
than said second resealable zone.
[0082] 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.
[0083] 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.
[0084] Preferably said vent consists of at least one aperture
through said plastic film, to allow passage therethrough of fluid
from said containment region.
[0085] Preferably said first resealable zone and second resealable
zone is established by any one or more of,
[0086] a reclosable profile strip
[0087] an adhesive band (with or without a peelable backing layer),
and
[0088] a foldable region.
[0089] Preferably said pouch is defined by,
[0090] (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
[0091] (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.
[0092] 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.
[0093] Preferably sealing of said edges is done by heat or
ultrasonic sealing.
[0094] 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.
[0095] 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.
[0096] Preferably sealing of said edges is done by heat or
ultrasonic sealing.
[0097] 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.
[0098] 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.
[0099] 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.
[0100] Preferably said interior-most ply at a region intermediate
of said first and second resealable zones, includes,
[0101] (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
[0102] (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,
[0103] 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.
[0104] Preferably said interior-most ply is of substantially
uniform thickness.
[0105] 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).
[0106] 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,
[0107] a first resealable zone extending completely across said
openable mouth, to allow closure of said openable mouth,
[0108] 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
[0109] 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,
[0110] wherein said interior-most ply, at a region intermediate of
said first and second resealable zones, includes
[0111] (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
[0112] (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,
[0113] 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
[0114] wherein said second resealable zone when sealed seals the
containment region from the exterior of said bag.
[0115] Preferably said pouch is defined by,
[0116] (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
[0117] (b) two overlying sheets of multi-ply plastics film, sealed
along all free edges save for the openable mouth.
[0118] Preferably said vent is closer to said first resealable zone
than said second resealable zone.
[0119] 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).
[0120] 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.
[0121] 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.
[0122] 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.
[0123] 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
[0124] Preferred forms of the present invention will now be
described with reference to the accompanying drawings of which;
[0125] FIG. 1 shows in perspective view an air tight storage bag
with the openable mouth in an upward orientation;
[0126] FIG. 2 shows the bag of FIG. 1 in side view showing the
locations of the first resealable zone, vent and second resealable
zone;
[0127] 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;
[0128] 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;
[0129] 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;
[0130] 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;
[0131] 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,
[0132] FIG. 8 shows in perspective view the location of content via
the openable mouth in the interior of the air tight storage
bag;
[0133] 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;
[0134] 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;
[0135] 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;
[0136] 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;
[0137] 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;
[0138] 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;
[0139] 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;
[0140] 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
[0141] 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
[0142] Preferred embodiments of the present invention shall now be
described with reference to the FIGS. 1 through 17.
[0143] 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 (5a) and (5b).
[0144] 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).
[0145] The interior (3) of the pouch is communicable to the
exterior (4) via the openable mouth (9).
[0146] 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.
[0147] 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 (5a)
and/or (5b) 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).
[0148] 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.
[0149] 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).
[0150] The walls (5a) and (5b) 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 (5a)
and (5b) 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 (5a) and (5b) can be made from
any method known in the art, such as extrusion, co-extrusion, and
lamination or similar.
[0151] The walls (5a) and (5b) 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.
[0152] The basic function of the vent (11) is to allow expelling of
air or gas, through at least one or both of the walls (5a) and (5b)
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.
[0153] 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.
[0154] 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 (5a) and (5b) 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.
[0155] 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).
[0156] 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).
[0157] 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).
[0158] 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.
[0159] 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).
[0160] 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 (5a) and (5b) 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 (5a) to the other
wall (5b). 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.
[0161] The preferred method of use of the present invention will
now be described.
[0162] 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.
[0163] 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).
[0164] 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.
[0165] 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.
[0166] 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.
[0167] The method of manufacture and construction of the air tight
storage bag will now be described.
[0168] 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).
[0169] 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.
[0170] The vent (11) and the first and second resealable zones can
be provided in the airtight storage bag in a number of ways.
[0171] 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.
[0172] 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.
[0173] 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.
[0174] 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).
[0175] 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).
[0176] 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.
[0177] 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.
[0178] 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.
[0179] 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.
[0180] 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.degree. Celsius or more. However at temperatures of less than
180.degree. the OPP material will not seal to itself or to the CPP
material.
[0181] 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).
[0182] 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.
[0183] Cross sections through the vent (11) are shown in FIGS. 5
and 6 for two different embodiments. The walls (5a) and (5b) 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 (5b) 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 (5a) is also of CPP.
[0184] FIG. 6 shows a similar cross sectional view to that of FIG.
5 with the exception that both walls (5a) and (5b) have an
intermediate strip (25) thereon forming the vent (11) in a similar
manner. There, both walls (5a) and (5b) 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 (5a)
and (5b) occurs between the respective interior most plies (15) of
the two walls (5a) and (5b), 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).
[0185] 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 (5a) and (5b), 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.
[0186] 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.
[0187] 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).
[0188] 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.
[0189] 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.
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