SYSTEM AND METHOD FOR FORMING AN INTEGRATED TRAY FOR USE IN VACUUM PACKAGING

SYSTEME ET PROCEDE PERMETTANT DE FORMER UN PLATEAU INTEGRE POUR EMBALLAGE SOUS VIDE

English Abstract

A bag for use in vacuum packaging can comprise a first panel (320) and a
second panel (322) overlapping each other. One or more trays (230) for
retaining a perishable or other product is formed on one or more of the
panels. Each tray can optionally have ridges (234) for suspending a product
above the tray so that liquid can collect in the tray. In one embodiment, a
method for forming such a bag between a cooling roll (104) and laminating roll
(102) includes feeding a gas-impermeable material (108) to a nip formed
between the rolls. Resin is extruded to the nip such that the resin fills a
plurality of cavities of the cooling roll, forming an inner layer that adheres
to the gas-impermeable material. A resultant sheet is then folded to form the
first and second panel and sealed such that an envelope is formed.

French Abstract

Poche pour emballage sous vide pouvant comprendre un premier et un second panneaux se recouvrant l'un l'autre. Un ou plusieurs plateaux destinés à recevoir des produits périssables ou autres sot formés dans au moins un des panneaux. Chaque plateau peut éventuellement comporter des rebords permettant de recueillir du liquide dans le plateau. Dans un mode de réalisation, l'invention concerne un procédé de fabrication d'un tel sac consistant à introduire un matériau imperméable aux gaz dans l'espace entre un rouleau de refroidissement et un rouleau de laminage. De la résine est extrudée dans l'écartement entre rouleaux se telle sorte qu'elle remplisse une pluralité de cavité dans le rouleau de refroidissement et forme une couche intérieure qui adhère sur le matériau imperméable aux gaz. La feuille ainsi obtenue est repliée pour former un premier et un second panneau, puis scellée pour former une poche. Pour d'autres caractéristiques, aspects et objets de l'invention, se reporter au spécifications, chiffres et caractéristiques.

Claims

11
CLAIMS
1. A bag adapted to receive an article, comprising:
a first panel defining a tray adapted to receive the article and a plurality
of
protuberances within the tray, which protuberances are adapted to support the
article over
a base of the tray;
a second panel; and
the first panel and the second panel secured together to form the bag.
2. The bag of claim 1 wherein said first panel is formed of a heat sealable
material and
said second panel is formed of a gas impermeable material.
3. A bag adapted to receive an article, comprising:
a first panel having:
a first outer layer; and
a first inner layer connected with the first outer layer, the first inner
layer including at least one tray integrally formed with the first inner
layer;
a second panel connected with the first panel such that the first panel and
the
second panel form an envelope having an inlet, the second panel having:
a second outer layer; and
a second inner layer connected with the second outer layer.
4. The bag of claim 3, further comprising a plurality of protuberances within
the at least
one trays.
5. The bag of claim 3, wherein the first outer layer and the second outer
layer comprise
a gas-impermeable material.

12
6. The bag of claim 5, wherein the gas-impermeable material is one of
polyester,
polyamide, ethylene vinyl alcohol, and nylon.
7. The bag of claim 3, wherein the first inner layer and the second inner
layer comprise
a thermoplastic resin.
8. The bag of claim 7, wherein the thermoplastic resin is polyethylene.
9. The bag of claim 5, wherein when the article is positioned within the tray,
the article
is supported by the plurality of protuberances.
10. The bag of claim 4, wherein when the article is positioned within the
tray, the article
is supported above a base of the at least one tray.
11. The bag of claim 4, wherein the plurality of protuberances define a
plurality of pockets
formed such that liquid can collect in the plurality of pockets; and
wherein when the article is positioned within the tray, the article is
positioned above
liquid collected in the plurality of pockets.
12. A bag adapted to receive an article, comprising:
a first panel including:
a first gas-impermeable layer; and
a first inner layer laminated to the first gas-impermeable layer, the
first inner layer including at least one tray integrally formed with the first
inner layer;
a second panel including:
a second gas-impermeable layer; and
a second inner layer laminated to the second gas-impermeable layer;

13
and
wherein the first panel is connected with the second panel to form an
envelope such that the first inner layer opposes the second inner layer, the
envelope
including a heat-sealable opening for evacuating gas.
13. The bag of claim 12, further comprising a plurality of protuberances
within the at least
one trays.
14. The bag of claim 12, wherein the first gas-impermeable layer and the
second gas-
impermeable layer comprise one of polyester, polyamide, ethylene vinyl
alcohol, and nylon.
15. The bag of claim 12, wherein the first inner layer and the second inner
layer comprise
a thermoplastic resin.
16. The bag of claim 15, wherein the thermoplastic resin is polyethylene.
17. The bag of claim 13, wherein when the article is positioned within the
tray, the article
is supported by the plurality of protuberances.
18. The bag of claim 13, wherein when the article is positioned within the
tray, the article
is supported above a base of the at least one tray.
19. The bag of claim 13, wherein the plurality of protuberances define a
plurality of
pockets formed such that liquid can collect in the plurality of pockets; and
wherein when the article is positioned within the tray, the article is
positioned above
liquid collected in the plurality of pockets.

14
20. A heat-sealable bag adapted to receive an article, comprising:
a first panel including:
a first gas-impermeable layer;
at least one first intermediate layer connected with the first gas-
impermeable layer; and
a first inner layer laminated to the at least one first intermediate layer,
the first inner layer including at least one tray integrally formed with the
first inner layer; and
a second panel including:
a second gas-impermeable layer;
at least one second intermediate layer connected with the second
gas-impermeable layer; and
a second inner layer laminated to the at least one second
intermediate layer;
wherein the first panel is connected with the second panel to form an
envelope such that the first inner layer opposes the second inner layer, the
envelope
including a heat-sealable opening for evacuating gas.
21. The bag of claim 20, further comprising a plurality of protuberances
within the at least
one trays.
22. The bag of claim 20, wherein the first gas-impermeable layer and the
second gas-
impermeable layer comprise one of polyester, polyamide, ethylene vinyl
alcohol, and nylon.
23. The bag of claim 20, wherein the first inner layer and the second inner
layer comprise
a thermoplastic resin.
24. The bag of claim 23, wherein the thermoplastic resin is polyethylene.

15
25. The bag of claim 21, wherein when the article is positioned within the
tray, the article
is supported by the plurality of protuberances.
26. The bag of claim 21, wherein when the article is positioned within the
tray, the article
is supported above a base of the at least one tray.
27. The bag of claim 21, wherein the plurality of protuberances define a
plurality of
pockets formed such that liquid can collect in the plurality of pockets; and
wherein when the article is positioned within the tray, the article is
positioned above
liquid collected in the plurality of pockets.
28. A method for forming a panel for use in a sealable bag, comprising:
flowing a material onto a backing film, such that the flowing material is
molded to form a structure;
wherein the structure includes a tray;
cooling the flowing material such that the flowing material solidifies to form
an inner layer having the structure; and
wherein the inner layer adheres to the backing film.
29. A method for forming a bag adapted to receive an article, the bag being
partially
formed between a laminating roll and a cooling roll having a plurality of
cavities for forming
a structure, comprising:
feeding a gas-impermeable film to a nip formed by the cooling roll and the
laminating roll;
extruding resin such that the resin fills the nip and the plurality of
cavities
exposed to the nip;
pressing the resin between the cooling roll and the laminating roll;

16
cooling the resin such that the resin forms the structure and adheres to the
gas-impermeable film, forming a panel;
folding the panel such that a first portion of the panel overlaps a second
portion of the panel;
applying heat to a first, second, and third side of the first and second
portions
such that an envelope is formed; and
wherein the structure includes one or more trays having a plurality of
protuberances.
30. A method for manufacturing a bag adapted to receive an article,
comprising:
feeding a first gas-impermeable film to a first nip formed by a first cooling
roll
and a first laminating roll, the first cooling roll having a plurality of
cavities for forming a
structure;
wherein the structure is one or more trays having a plurality of
protuberances;
extruding resin such that the resin fills the first nip and the plurality of
cavities
exposed to the first nip;
pressing the resin between the first cooling roll and the first laminating
roll;
cooling the resin such that the resin forms the structure and adheres to the
first gas-impermeable film, forming a first panel;
feeding a second gas-impermeable film to a second nip formed by a second
cooling roll and a second laminating roll;
extruding resin such that the resin fills the second nip;
pressing the resin between the second cooling roll and the second laminating
roll;
cooling the resin such that the resin adheres to the second gas-impermeable
film, forming a second panel;
overlapping the first panel with the second panel;

17
applying heat to a first, second, and third side of the first and second
panels
such that an envelope is formed; and
wherein the structure includes one or more trays having a plurality of
protuberances.
31. A method for manufacturing a bag adapted to receive an article,
comprising:
rotating a first cooling roll at a first rate, the first cooling roll
including a
plurality of cavities for forming a structure;
wherein the structure includes one or more trays having a plurality of
protuberances;
rotating a first laminating roll at a second rate;
introducing a first film to a first nip between the first cooling roll and the
first
laminating roll;
extruding molten material to the first nip;
pressing the molten material between the first cooling roll and the first film
such that the molten material fills the plurality of cavities exposed to the
first nip;
cooling the molten material such that a first inner layer is formed;
wherein the first inner layer includes the structure;
wherein the first inner layer adheres to the first film, thereby forming a
first
panel;
rotating a second cooling roll at a third rate;
rotating a second laminating roll at a fourth rate;
introducing a second film to a second nip between the second cooling roll and
the second laminating roll;
extruding molten material to the second nip;
pressing the molten material between the second cooling roll and the second
film;

18
cooling the molten material such that a second inner layer is formed;
wherein the second inner layer adheres to the second film, thereby forming
a second panel;
overlapping the first panel with the second panel; and
applying heat to a portion of a periphery of the first and second panels such
that the first panel and the second panel form an envelope.
32. The method of claim 31, wherein the second rate is an integer multiple of
the first rate
and the fourth rate is an integer multiple of the third rate.
33. The method of claim 31, wherein the first film and the second film
comprise at least
one layer.
34. The method of claim 33, wherein the at least one layer comprises a gas-
impermeable
material.
35. The method of claim 34, wherein the gas-impermeable material is one of
polyester,
polyamide, ethylene vinyl alcohol, and nylon.
36. The method of claim 31, wherein the molten material is polyethylene.
37. The method of claim 31, wherein a thickness of the first inner layer is
determined by
the size of the first nip and the thickness of the second inner layer is
determined by the size
of the second nip.
38. The method of claim 31, wherein the structure is formed such that when the
article
is positioned within the tray, the article is supported by the plurality of
protuberances.

19
39. The method of claim 31, wherein the structure is formed such that when the
article
is positioned within the tray, the article is supported above a base of the at
least one tray.
40. A method of manufacturing a bag adapted to receive an article, comprising:
rotating a first roller having a plurality of recesses that can define one or
more
trays including a plurality of protuberances;
rotating a second roller adjacent to the first roller, said second roller can
feed
a first film adjacent to the first roller;
applying a molten material between the first roller and the film;
said molten material filling the recesses of the first roller, and said molten
material and film moving between the first roller and the second roller
forming a first panel
with a plurality of receptacles;
forming a second panel; and
mating the first panel to the second panel in order to form a bag.
41. The method of claim 40, further comprising:
using a gas impermeable material for the film; and
using a heat sealable material for the molten material.
42. The method of claim 41, wherein the first panel is formed such that when
the article
is positioned within the tray, the article is supported by the plurality of
protuberances.
43. The method of claim 41, wherein the first panel is formed such that when
the article
is positioned within the tray, the article is supported above a base of the at
least one tray.
44. The method of claim 40, wherein said second panel is formed with the first
roller and
the second roller.

20
45. The method of claim 40, wherein said second panel is formed with the first
roller and
the second roller, and the mating step includes folding the first panel over
the second panel.
46. The method of claim 40, wherein said first roller includes a peripheral
surface having
a first portion including the plurality of recesses for defining the one or
more trays including
the plurality of protuberances.
47. A method for manufacturing a bag adapted to receive an article,
comprising:
feeding a first gas-impermeable film to a first nip formed by a first cooling
roll
and a first laminating roll, the first cooling roll having a plurality of
cavities for forming at least
one tray;
extruding resin such that the resin fills the first nip and the plurality of
cavities
exposed to the first nip;
pressing the resin between the first cooling roll and the first laminating
roll;
cooling the resin such that a first inner layer having the first structure and
the
second structure is formed;
wherein the first inner layer adheres to the first gas-impermeable film,
thereby
forming a first panel;
feeding a second gas-impermeable film to a second nip formed by a second
cooling roll and a second laminating roll, the second cooling roll having a
plurality of cavities
and protuberances for forming a third structure;
wherein the third structure is the other of the receiving feature and the
insertion feature;
extruding resin such that the resin fills the second nip and the plurality of
cavities exposed to the second nip;
pressing the resin between the second cooling roll and the second laminating
roll;

21
cooling the resin such that a second inner layer having the third structure is
formed;
wherein the second inner layer adheres to the first gas-impermeable film,
thereby forming a second panel;
overlapping the first panel with the second panel; and
applying heat to a first, second, and third side of the first and second
panels.

Description

CA 02517894 2005-09-O1
WO 2004/078591 PCT/US2004/006774
SYSTEM AND METHOD FOR FORMING AN INTEGRATED TRAY
FOR USE IN VACUUM PACKAGING
CLAIM OF PRIORITY
[0001] This application claims priority from U.S. Provisional Patent
Application No.
60/452,172, entitled "SEALABLE BAG HAVING AN INTEGRATED TRAY FOR USE IN
VACUUM PACKAGING," by Henry Wu, et al., filed March 5, 2003 (Attorney Docket
No. TILA-
01178US0); U.S. Provisional Patent Application No. 60/452,171, entitled
"METHOD FOR
MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED TRAY FOR USE IN
VACUUM PACKAGING," by Henry Wu, et al., filed March 5, 2003 (Attorney Docket
No. TILA-
01178US1 ); U.S. Patent Application No. 10l ,- entitled "SEALABLE BAG HAVING
AN
INTEGRATED TRAY FOR USE IN VACUUM PACKAGING," by Hongyu Wu, et al., filed
March 4, 2004 (Attorney Docket No. TILA-01178US2); and U.S. Patent Application
No.
10/ ,- entitled "METHOD FOR MANUFACTURING A SEALABLE BAG HAVING AN
INTEGRATED TRAY FOR USE IN VACUUM PACKAGING," by Hongyu Wu, et al., filed
March 4, 2004 (Attorney Docket No. TILA-01178US3).
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0002] This application incorporates by reference all of the following co-
pending
applications:
[0003] U.S. Provisional Patent Application No. 60/452,168, entitled "LIQUID-
TRAPPING BAG FOR USE IN VACUUM PACKAGING," by Henry Wu, et al., filed March 5,
2003 (Attorney Docket No. TILA-01177US0);
[0004] U.S. Provisional Patent Application No. 60/452,171, entitled "METHOD
FOR
MANUFACTURING A LIQUID-TRAPPING BAG FOR USE IN VACUUM PACKAGING," by
Henry Wu, et al., filed March 5, 2003 (Attorney Docket No. TILA-01177US1 );
[0005] U.S. Provisional PatentApplication No. 60/451,954, entitled "SEALABLE
BAG
HAVING AN INDICIA FOR USE IN VACUUM PACKAGING," by Henry Wu, et al., filed
March
5, 2003 (Attorney Docket No. TILA-01179US0);
[0006] U.S. Provisional Patent Application No. 60/451,948, entitled "METHOD
FOR
MANUFACTURING A SEALABLE BAG HAVING AN INDICIA FOR USE IN VACUUM
PACKAGING," by Henry Wu, et al., filed March 5, 2003 (Attorney Docket No. TILA-
01179US1 );
[0007] U.S. Provisional PatentApplication No.60/452,142, entitled "SEALABLE
BAG
HAVING AN INTEGRATED ZIPPER FOR USE IN VACUUM PACKAGING," by Henry Wu,
et al., filed March 5, 2003 (Attorney Docket No. TILA-01180US0);

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2
[0008] U.S. Provisional Patent Application No. 60/452,021, entitled "METHOD
FOR
MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED ZIPPER FOR USE IN
VACUUM PACKAGING," by Henry Wu, et al., filed March 5, 2003 (Attorney Docket
No. TILA-
01180US1 );
[0009] U.S. Provisional PatentApplication No. 60/451,955, entitled "SEALABLE
BAG
HAVING AN INTEGRATED VALVE STRUCTURE FOR USE IN VACUUM PACKAGING," by
Henry Wu, et al., filed March 5, 2003 (Attorney Docket No. TILA-01181 USO);
[0010] U.S. Provisional Patent Application No. 60/451,956, entitled "METHOD
FOR
MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED VALVE STRUCTURE
FOR USE IN VACUUM PACKAGING," by Henry Wu, et al., filed March 5, 2003
(Attorney
Docket No. TILA-01181 US1 );
[0011] U.S. Provisional PatentApplication No. 60/452,157, entitled "SEALABLE
BAG
HAVING AN INTEGRATED TIMER/SENSOR FOR USE IN VACUUM PACKAGING," by
Henry Wu, et al., filed March 5, 2003 (Attorney Docket No. TILA-01182US0);
[0012] U.S. Provisional Patent Application No. 60/452,139, entitled "METHOD
FOR
MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED TIMERISENSOR FOR
USE IN VACUUM PACKAGING," by Henry Wu, et al., filed March 5, 2003 (Attorney
Docket
No. TILA-01182US1 );
[0013] U.S. Patent Application No. 10/169,485, entitled "METHOD FOR
~ PREPARING AIR CHANNEL EQUIPPED FILM FOR USE IN VACUUM PACKAGE," filed
June 26, 2002;
[0014] U.S. Patent Application No. 10/ ,-, entitled "LIQUID-TRAPPING BAG
FOR USE IN VACUUM PACKAGING," by Hongyu Wu, et al., filed March 4, 2004
(Attorney
Docket No. TILA-01177US2);
[0015] U.S. Patent Application No. 10/-, , entitled "METHOD FOR
MANUFACTURING LIQUID-TRAPPING BAG FOR USE IN VACUUM PACKAGING," by
Hongyu Wu, et al., filed March 4, 2004 (Attorney Docket No. TILA-01177US3);
[0016] U.S. Patent Application No.10/ , , entitled "SEALABLE BAG HAVING
AN INDICIA FOR USE IN VACUUM PACKAGING," by Hongyu Wu, et al., filed March 4,
2004
(Attorney Docket No. TILA-01179US2);
[0017] U.S. Patent Application No. 10/ , , entitled "METHOD FOR
MANUFACTURING A SEALABLE BAG HAVING AN INDICIA FOR USE IN VACUUM
PACKAGING," by Hongyu Wu, et al., filed March 4, 2004 (Attorney Docket No.
TILA-
01179US3);
[0018] U.S. Patent Application No.10/ ,-, entitled,"SEALABLE BAG HAVING
AN INTEGRATED ZIPPER FOR USE IN VACUUM PACKAGING," by Hongyu Wu, et al.,

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3
filed March 4, 2004 (Attorney Docket No. TILA-01180US2);
[0019] U.S. Patent Application No. 10/ -, entitled, "METHOD FOR
MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED ZIPPER FOR USE IN
VACUUM PACK/~,GING," by Hongyu Wu, et al., filed March 4, 2004 (Attorney
Docket No.
TILA-01180US3);
[0020] U.S. Patent Application No.10/ ,-, entitled, "SEALABLE BAG HAVING
AN INTEGRATED VALVE STRUCTURE FOR USE IN VACUUM PACKAGING," by Hongyu
Wu, et al., filed March 4, 2004 (Attorney Docket No. TILA-01181 US2);
[0021] U.S. Patent Application No. 10/-, , entitled, "METHOD FOR
MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED VALVE STRUCTURE
FOR USE IN VACUUM PACKAGING," by Hongyu Wu, et al., filed March 4, 2004
(Attorney
Docket No. TILA-01181 US3);
[0022] U.S. Patent Application No.10/ -, entitled, "SEALABLE BAG HAVING
AN INTEGRATED TIMER/SENSOR FOR USE IN VACUUM PACKAGING," by Hongyu Wu,
et al., filed March 4, 2004 (Attorney Docket No. TILA-01182US2); and
[0023] U.S. Patent Application No. 10/ ,- entitled, "METHOD FOR
MANUFACTURING A SEALABLE BAG HAVING AN INTEGRATED TIMER/SENSOR FOR
USE IN VACUUM PACKAGING," by Hongyu Wu, et al., filed March 4, 2004 (Attorney
Docket
No. TILA-01182US3).
FIEL~ ~F THE 11~~9EI~TI~1~
[0024] The present invention relates to bags for use in vacuum packaging and
methods and devices for manufacturing bags for use in vacuum packaging.
BACKGROUN~
[0025] Methods and devices for preserving perishable foods such as fish and
meats,
processed foods, prepared meals, and left-overs, and non-perishable items are
widely known,
and widely varied. Foods are perishable because organisms such as bacteria,
fungus and
mold grow over time after a food container is opened and the food is left
exposed to the
atmosphere. Most methods and devices preserve food by protecting food from
organism-filled
air. A common method and device includes placing food into a gas-impermeable
plastic bag,
evacuating the air from the bag using suction from a vacuum pump or other
suction source,

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4
and tightly sealing the bag.
[0026] A bag for use in vacuum packaging can consist of a first panel and
second
panel, each panel consisting of a single layer of heat-sealable, plastic-based
film (for
example, polyethylene). The panels are sealed together along a substantial
portion of the
periphery of the panels by heat-sealing techniques so as to form an envelope.
Perishable
products, such as spoilable food, or other products are packed into the
envelope via the
unsealed portion through which air is subsequently evacuated. After perishable
products are
packed into the bag and air is evacuated from the inside of the bag, the
unsealed portion is
heated and pressed such that the panels adhere to each other, sealing the bag.
[0027] U.S. Pat. No. 2,778,173, incorporated herein by reference, discloses a
method for improving the evacuation of air from the bag by forming channels in
at least one
of the panels with the aid of embossing techniques. Air escapes from the bag
along the
channels during evacuation. The embossing forms a pattern of protuberances on
at least one
of the panels. The protuberances can be discrete pyramids, hemispheres, etc.,
and are
formed by pressing a panel using heated female and male dies. The first panel
is overlaid on
the second panel such that the protuberances from one panel face the opposite
panel. The
contacting peripheral edges of the panels are sealed to each other to form an
envelope
having an inlet at an unsealed portion of the periphery. The perishable or
other products are
packed into the envelope through the inlet, and the inlet is sealed.
Thereafter, an opening is
pierced in a part of the panel material that communicates with the channels,
air is removed
from the interior of the envelope through the channels and opening, and the
opening is
sealed. This type of bag requires two additional sealing steps after the
perishable or other
product is packed into the envelope. One further problem is that embossing
creates
impressions on the plastic such that indentations are formed on the opposite
side of the panel
[0028] To avoid additional sealing steps, a vacuum bag is formed having a
first
panel and a second panel consisting of laminated films. Each panel comprises a
heat-
sealable inner layer, a gas-impermeable outer layer, and optionally, one or
more intermediate

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layers. Such a bag is described in U.S. Pat. No. Re. 34,929, incorporated
herein by reference.
At least one film from at least one panel is embossed using an embossing mold
to form
protuberances and channels defined by the space between protuberances, so that
air is
readily evacuated from the vacuum bag.
5 [0029] U.S. Pat. No. 5,554,423, incorporated herein by reference, discloses
still
another bag usable in vacuum packaging. The bag consists of a first and second
panel, each
panel consisting of a gas-impermeable outer layer and a heat-sealable inner
layer. A plurality
of heat-sealable strand elements are heat bonded at regular intervals to the
inner layer of
either the first panel or the second panel. The spaces between strand elements
act as
channels for the evacuation of air. The strand elements are extruded from an
extrusion head
and heat bonded to the heat-sealable layer by use of pressure rolls. Separate
equipment is
required for producing strand elements, and a procedure of heat bonding a
plurality of strand
elements at regular intervals to the heat-sealable inner layer is complicated.
Also, various
shapes of pattern are hard to form using this process.
BRIEF ~ESCI<:IPTI~N ~F THE FIGURES
[0030] Further details of embodiments of the present invention are explained
with
the help of the attached drawings in which:
[0031] FIG. 1A is a perspective view of a method for manufacturing a vacuum
bag
in accordance with one embodiment of the present invention;
[0032] FIG. 1B is a side view of the method shown in FIG. 1A illustrating the
embossing method used in an embodiment of the present invention;
[0033] FIG. 1C is a close-up view of a portion of FIG. 1B;
[0034] FIG. 2A is a plan view of a panel in accordance with one embodiment of
the
present invention, manufactured by the process shown in FIG. 1A-1C;
[0035] FIG. 2B is a cross-section view of a panel in accordance with one
embodiment ofthe present invention, manufactured bythe process shown in FIG.1A-
1 C; and

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6
[0036] FIG. 3 is a perspective view of a vacuum bag in accordance with one
embodiment of the present invention.
DETAILED DESCRIPTION
[0037] FIGS. 1A-1C illustrate one embodiment of a method for manufacturing a
vacuum bag in accordance with the present invention. The vacuum bag comprises
a first
panel and a second panel, wherein each panel comprises a gas-impermeable base
layer 108
and a heat-sealable inner layer 106 with at least one panel having raised
walls for preventing
shifting of perishable or other product contained inside the vacuum bag. A
laminating roll 102
and a cooling roll 104 are arranged so that the heat-sealable inner layer 106
can be laminated
to the gas-impermeable base layer 108 as the melt-extruded resin is cooled. As
illustrated in
FIG. 1C, the gap between the laminating roll 102 and the cooling roll 104 can
be controlled
according to specifications (for example, thickness) of a panel for use in
vacuum packaging.
The temperature of the cooling roll 104 is maintained in a range such that the
melt-extruded
heat-sealable resin is sufficiently cooled to form the desired pattern. For
example, a
temperature range of about -15° to about -10° can be sufficient
to properly form the desired
pattern. The temperature range of the cooling roll 104 can vary according to
the composition
of the resin, the composition of the gas-impermeable base layer 108,
environmental
conditions, etc. and can require calibration. Also, the cooling roll 104 can
be sized to have a
larger diameter than the laminating roll 102, thereby bringing the melt-
extruded resin into
contact with more cooled surface area. For example, the diameter of the
cooling roll 104 can
be about one-and-a-half to about three times as large as that of the
laminating roll 102.
[0038] The heat-sealable inner layer 106 is typically made of a thermoplastic
resin.
For example, the resin can be comprised of polyethylene (PE) suitable for
preserving foods
and harmless to a human body. A vacuum bag can be manufactured by overlapping
two
panels such that the heat-sealable resin layers 106 of the two panels is
brought into contact

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7
and heat is applied to a portion of the periphery of the panels to form an
envelope. The
thermoplastic resin can be chosen so that the two panels strongly bond to each
other when
sufficient heat is applied.
[0039] The gas-impermeable base layer 108 is fed to the gap between the
cooling
roll 104 and the laminating roll 102 by a feeding means (not shown). The gas-
impermeable
base layer can be comprised of polyester, polyamide, ethylene vinyl alcohol
(EVOH), nylon,
or other material having similar properties and capable of being used in this
manufacturing
process, and also capable of being heated. The gas-impermeable base layer 108
can consist
of one layer, or two or more layers. When employing a multilayer-structured
base layer, it
should be understood that a total thickness thereof is also adjusted within
the allowable range
for the total gas-impermeable base layer 108.
[0040] An extruder 110 is positioned in such a way that the melt-extruded
resin is
layered on the gas-impermeable base layer 108 by feeding the melt-extruded
resin to the nip
between the cooling roll 104 and the gas-impermeable layer 108. The resin is
fed through a
nozzle 112 of the extruder 110. The temperature of the melt-extruded resin is
dependent on
the type of resin used, and can typically range from about 200° to
about 250°. The amount
of resin to be extruded into the laminating unit 100 is dependent on the
desired thickness of
the heat-sealable inner layer 106.
[0041] A pattern fabricated on the circumferential surface of the cooling roll
104 in
accordance with one embodiment of the present invention can include cavities
for forming
raised walls defining one or more discrete trays. The pattern can also
optionally include
cavities (and/or protuberances) forforming ridges or protuberances within the
raised walls for
suspending a perishable or other product over a base of the trays, thereby
allowing liquid to
collect in the tray. The resin extruded by the nozzle 112 is pressed between
the cooling roll
104 and the gas-impermeable base layer 108 and flows into the cavities of the
cooling roll
104. The melt-extruded resin quickly cools and solidifies in the desired
pattern while adhering

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8
to the gas-impermeable base layer 108, thereby forming the heat sealable inner
layer 106 of
the panel. The heat-sealable inner layer 106 can be formed while the resin is
sufficiently
heated to allow the resin to flow, thereby molding the resin, unlike
conventional methods
adopting a post-embossing treatment where the heat-sealable inner layer is
drawn by a die
or embossed between male and female components.
[0042] FIG. 2A is a plan view of a panel formed by the cooling roll 104 for
use in a
vacuum bag, in which the heat-sealable inner layer 106 is molded in such a way
that raised
walls 232 are formed for defining a tray 230 for restricting the movement of
perishable or
other products. Within the raised walls 232 of the tray are ridges 234 for
suspending the
perishable or other products over the base of the tray. As shown, the ridges
234 are cross-
hatched and form reservoirs 236 for liquid to collect. In other embodiments,
the ridges can
be formed in a multitude of different patterns, allowing for the formation of
reservoirs 236
having a multitude of different shapes and sizes. In still other embodiments,
the tray 230 can
include protuberances, wherein the protuberances can be discrete pyramids,
hemispheres,
etc., thereby allowing liquid to collect evenly in the base of the tray 230.
In still other
embodiments, the panel 220 can include a plurality of discrete trays 230, each
sized to suit
t
an application and optionally having ridges 234 or protuberances. One of
ordinary skill in the
art can appreciate the myriad of different ways in which the panel 220 can be
configured to
restrict the movement of perishable products within a vacuum bag.
[0043] The thickness of the raised walls 232 and ridges 234 formed on the heat-
sealable inner layer 106 of a panel 220 can be determined by the depth of the
cavities of the
cooling roll 104, and the width of the raised walls 232 and ridges 234 can be
determined by
the width of the cavities. Thus, the shape, width, and thickness of the raised
walls 232 and
ridges 234 can be controlled by changing the specifications for the cavities
of the cooling roll
104. FIG.2B is a cross-sectional view of the panel 220 described above. In the
heat-sealable
inner layer 106, the raised walls 232 can range, for example, from about 35-75
mils or more

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9
in height, the gas-impermeable base layer 108 can range, for example, from
about 0.5-8.0
mils in thickness, and the heat-sealable inner layer 106, can range, for
example, from about
0.5-6.0 mils in thickness (without the raised walls 232). Optionally, ridges
234 or
protuberances can by included. The ridges 234 or protuberances can have a
height lower
than the raised walls 232, thereby suspending the perishable or other product
while still
retaining the perishable product within the tray 230. For example, if the
raised wall 232 is 75
mils in height, the height of the ridges 234 or protuberances can be about 30
mils. The
dimensions of the raised walls 232, the ridges 234, the base layer 108, and
the inner layer
106 are set forth to illustrate, but are not to be construed to limit the
dimensions.
[0044] FIG. 3 illustrates a bag for use in vacuum packaging in accordance with
one
embodiment of the present invention. The vacuum bag 350 comprises a first
panel 320 and
a second panel 322 overlapping each other. At least one tray 230 is formed on
the first panel
320 in accordance with an embodiment described above. The second panel 322 (or
first
panel 320) optionally includes channels (not shown) along a portion of the
panel for
evacuating air and other gases from the bag. The channels can be formed, for
example, as
described in the cross-referenced application "LIQUID-TRAPPING SAG FOR
VACUUfr/l
PACKAGING," incorporated herein by reference. The heat-sealable resin layer
106 and the
gas-impermeable base layer 108 of the first and second panels 320,322 are
typically made
of the same material respectively, but can alternatively be made of different
materials that
exhibit heat-sealability and gas-impermeability respectively. As described
above, the heat-
sealable resin layer 106 is used as an inner layer and the gas-impermeable
base layer 108
is used as an outer layer. The lower, left, and right edges of the first and
the second panel
320,322 are bonded to each other by heating, so as to form an envelope for
receiving a
perishable or other product to be vacuum packaged. Once a perishable or other
product is
placed in the vacuum bag 350, air and/or other gases can be evacuated from the
bag 350,
for example by a vacuum sealing machine as described in U.S. Pat. No.
4,941,310, which is

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incorporated herein by reference. Once the air and/or other gases are
evacuated to the
satisfaction of the user, the inlet can be sealed by applying heat, thereby
activating the heat-
sealable inner layers 106 and bonding them together.
(0045] The foregoing description of preferred embodiments ofthe present
invention
5 has been provided for the purposes of illustration and description. It is
not intended to be
exhaustive or to limit the invention to the precise forms disclosed.
Obviously, many
modifications and variations will be apparent to the practitioner skilled in
the art. The
embodiments were chosen and described in order to best explain the principles
of the
invention and its practical application, thereby enabling others skilled in
the art to understand
10 the invention for various embodiments and with various modifications that
are suited to the
particular use contemplated. It is intended that the scope of the invention be
defined by the
following claims and their equivalence.

Representative Drawing