U.S. patent application number 11/185536 was filed with the patent office on 2006-04-06 for multi-layer film for forming a vacuum packaging bag and method of manufacture.
Invention is credited to Hongyu Wu.
Application Number | 20060072860 11/185536 |
Document ID | / |
Family ID | 36125644 |
Filed Date | 2006-04-06 |
United States Patent
Application |
20060072860 |
Kind Code |
A1 |
Wu; Hongyu |
April 6, 2006 |
Multi-layer film for forming a vacuum packaging bag and method of
manufacture
Abstract
A vacuum packaging film with an improved embossed pattern
suitable for evacuation of gas from a vacuum packaging bag made of
the film. The embossed pattern includes a plurality of roughly
parallel sequences of substantially collinear ridges. The ridges of
a first sequence are offset with respect to the ridges of an
adjacent second sequence.
Inventors: |
Wu; Hongyu; (San Jose,
CA) |
Correspondence
Address: |
PERKINS COIE LLP
P.O. BOX 2168
MENLO PARK
CA
94026
US
|
Family ID: |
36125644 |
Appl. No.: |
11/185536 |
Filed: |
July 19, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60611114 |
Sep 17, 2004 |
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Current U.S.
Class: |
383/101 ;
383/105; 383/109 |
Current CPC
Class: |
B29C 59/06 20130101;
B32B 2250/24 20130101; B32B 3/263 20130101; B32B 2439/46 20130101;
B31B 2155/002 20170801; B32B 27/36 20130101; B29C 48/0014 20190201;
B29C 48/08 20190201; B32B 27/32 20130101; B29C 51/225 20130101;
B29C 48/915 20190201; B29C 48/914 20190201; B29C 51/14 20130101;
B32B 3/30 20130101; B32B 7/03 20190101; B32B 2307/7242 20130101;
B65D 31/02 20130101; B31B 2155/00 20170801; B65D 81/2038 20130101;
B31B 2170/20 20170801; B29C 59/007 20130101; B29L 2009/00 20130101;
B29C 2791/007 20130101; B29C 48/21 20190201; B32B 2439/70 20130101;
B29C 2791/006 20130101; B32B 27/08 20130101; B32B 2307/31 20130101;
B65D 81/2007 20130101; B65D 33/01 20130101; B32B 27/34 20130101;
B31B 2160/10 20170801 |
Class at
Publication: |
383/101 ;
383/109; 383/105 |
International
Class: |
B65D 33/01 20060101
B65D033/01; B65D 33/00 20060101 B65D033/00; B65D 30/08 20060101
B65D030/08 |
Claims
1. A multi-layer film suitable for use in forming a vacuum
packaging bag, said multi-layer film comprising: a first layer made
of a first material; and a second layer made of a second material
that is formed onto said first layer, said second layer having a
pattern that is operable to form channels suitable for evacuation
of gas from a vacuum packaging bag made of said film, said pattern
including a plurality of roughly parallel sequences of
substantially collinear ridges, wherein ridges of a first sequence
of said parallel sequences of substantially collinear ridges are
offset with respect to an adjacent second sequence of said parallel
sequences of substantially collinear ridges.
2. The film of claim 1, wherein said first material is a
gas-impermeable material, and wherein said first layer is a
gas-impermeable layer.
3. The film of claim 1, wherein said pattern is embossed onto said
first layer as well as said second layer.
4. The film of claim 1, wherein said second material is a
heat-sealable resin, and wherein said second layer is a
heat-sealable resin layer.
5. The film of claim 4, wherein said heat-sealable resin is a
polyethylene resin.
6. The film of claim 1, further comprising a third material in
between said first material and said second material, said third
material forming a bonding layer between said first and second
layers.
7. The film of claim 1, further comprising a fourth material and a
fifth material, said fourth material forming a bonding layer
between said first layer and a fifth layer made of said fifth
material, wherein said fifth layer is a structural layer for
providing structural strength to said film.
8. The film of claim 1, wherein said substantially collinear ridges
have a striped pattern.
9. The film of claim 1, wherein said substantially collinear ridges
have a zigzag pattern.
10. The film of claim 1, wherein said substantially collinear
ridges have a wave pattern.
11. The film of claim 1, wherein said substantially collinear
ridges have an uneven pattern.
12. A method of manufacturing a multi-layer film for use in vacuum
packaging applications, said multi-layer film having a pattern that
operates to form channels suitable for evacuation of gas when said
multi-layer film is used in the creation of a vacuum packaging bag,
said method comprising the acts of: heat-extruding a first material
onto a roller; and heat-extruding a second material onto said
roller such that said first and second extruded materials bond and
form a film of said first material with a plurality of roughly
parallel sequences of substantially collinear ridges of said second
material forming a pattern on said film, said pattern operable to
form channels suitable for evacuation of gas from a vacuum
packaging bag made from said film.
13. The method of claim 12, wherein said first material is a
gas-impermeable material, said method further comprising forming a
gas-impermeable layer as a first layer of said film.
14. The method of claim 14, further comprising the act of
heat-extruding a third material in between said first and second
material, wherein said third material forms a bonding layer between
a first layer made of said first material and a second layer made
of said second material.
15. The method of claim 12, further comprising the act of
heat-extruding a fourth material and a fifth material to
respectively form a bonding layer and a structural layer, wherein
said bonding layer bonds said structural layer to a first layer
made of said first material, and wherein said structural layer
provides structural strength to said film.
16. The method of claim 12, further comprising the act of
controlling a temperature of said roller in order to properly
effectuate cooling and formation of said first and second
layers.
17. The method of claim 12, wherein the act of applying a pattern
to said first and second layers is accomplished by providing said
pattern on the circumferential surface of said roller.
18. The method of claim 12, wherein the act of applying a pattern
to said first and second layers is accomplished by using an air
knife to shape said first and second materials subsequent to
extrusion.
19. The method of claim 19, wherein said air-knife includes an
inverse vacuum, further comprising imparting said pattern on said
first and second materials using said inverse vacuum.
20. A vacuum packaging bag for holding food or other product, said
vacuum packaging bag comprising: a first sheet formed of a
multi-layer plastic film, said multi-layer plastic film including:
a first layer made of a first material; and a second layer made of
a second material that is laminated onto said first layer, said
second layer having an embossed pattern that is operable to form
channels suitable for evacuation of gas from a vacuum packaging bag
made of said film, said embossed pattern including a plurality of
roughly parallel sequences of substantially collinear ridges,
wherein ridges of a first sequence of said parallel sequences of
substantially collinear ridges are offset with respect to an
adjacent second sequence of said parallel sequences of
substantially collinear ridges; a second sheet formed of said
multi-layer plastic film, said second sheet having a footprint
substantially similar to said first sheet, wherein said first and
second sheets are arranged with respective second layers facing one
another, said first and second sheets sealed on opposing lateral
sides and at an end side, whereby said first and second sheets form
a vacuum packaging bag having an opening for insertion of food or
other product, said vacuum packaging bag sealable at said opening.
Description
RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent
Application No. 60/611,114, entitled "MULTI-LAYER FILM FOR FORMING
A VACUUM PACKAGING BAG AND METHOD OF MANUFACTURE", by Hongyu Wu,
filed on Sep. 17, 2004, and which is hereby incorporated by
reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to vacuum packaging
film, and more particularly to patterned vacuum packaging film.
BACKGROUND OF THE INVENTION
[0003] Vacuum packaging film is used for vacuum sealing of
perishable items. Due to the film's versatility in producing vacuum
sealed packages of various sizes, its popularity has increased in
recent years. As a result, continuous product improvement is
required on the part of manufacturers in order to stay competitive.
One such improvement has been applying patterns to vacuum packaging
bags.
[0004] For vacuum packaging bags with smooth inner surfaces (i.e.,
inner surfaces that do not have a pattern), the bag surfaces
sometimes stick together when air is evacuated from the bag during
vacuum packaging. This may result in air pockets within the seal
and degraded seal integrity. In response to this problem,
manufacturers may imprint or emboss a pattern onto vacuum packaging
film used to form the vacuum packaging bags. The pattern helps
prevent vacuum packaging bag surfaces from sticking together during
vacuum packaging by forming channels along the grooves of an
imprinted pattern--or forming channels between raised portions of
an embossed pattern--when the surfaces of the bag are face to face.
The pattern may be applied to one or both of the inner surfaces of
the vacuum packaging bag.
[0005] While imprinting or embossing a pattern onto vacuum
packaging film is generally desirable, imprinting or embossing a
pattern introduces new problems. For example, embossed patterns may
be less durable than smooth surfaces. In general, the farther an
embossed pattern sticks out from the surface of vacuum packaging
film, the less durable the film becomes. Moreover, thicker
embossing--or deeper grooves--typically consumes more material and
may be harder to apply to or form into the film. Thicker
embossing--or deeper grooves--also typically results in thicker
vacuum packaging film, which makes the film heavier and less
compact so it takes up more space in storage. Furthermore, if the
surface of a vacuum packaging film has a high concentration of
raised areas, there will be fewer channels formed when evacuating a
vacuum packaging bag made of the film. Since there are fewer
channels, even if relatively few channels become blocked gas may be
trapped and air pockets formed, resulting in degraded seal
integrity.
[0006] Accordingly, what is needed is a vacuum packaging film with
an improved embossing pattern to reduce embossing thickness, to
reduce the concentration of raised areas on vacuum packaging film,
or to increase the number of channels formed when the vacuum
packaging film is used in a vacuum packaging application.
SUMMARY OF THE INVENTION
[0007] The present invention fills these needs by providing a
vacuum packaging film with an improved embossed pattern suitable
for evacuation of gas from a vacuum packaging bag made of the film.
In an aspect of the present invention, the embossed pattern
includes a plurality of roughly parallel sequences of substantially
collinear ridges. The ridges of a first sequence are offset with
respect to the ridges of an adjacent second sequence.
[0008] A method for making vacuum packaging film, in accordance
with an aspect of the present invention, includes heat extruding a
first material onto a spinning cooling roll and heat extruding a
second material onto the spinning cooling roll. The first and
second extruded materials bond and form a film of the first
material with a plurality of roughly parallel sequences of
substantially collinear ridges of the second material forming a
pattern on the film. The pattern is operable to form channels
suitable for evacuation of gas from a vacuum packaging bag made
from the film.
[0009] A vacuum packaging bag made of the vacuum packaging film
according to an aspect of the present invention includes a first
sheet and a second sheet. The first and second sheets are formed of
the vacuum packaging film. The second sheet has a footprint
substantially similar to the first sheet. The first and second
sheets are arranged with respective second layers facing one
another. The first and second sheets are sealed on opposing lateral
sides and an end side, whereby the first and second sheets form a
vacuum packaging bag with an opening for insertion of food or other
product. The vacuum packaging bag is sealable at the opening.
[0010] A vacuum packaging bag roll, suitable for forming vacuum
packaging bags, made of the vacuum packaging film according to an
aspect of the present invention includes a first sheet and a second
sheet. The first and second sheets are formed of the vacuum
packaging film. The second sheet has a footprint substantially
similar to the first sheet. The first and second sheets are
arranged with respective second layers facing one another. The
first and second sheets are sealed on opposing lateral sides,
wherein portions of the bag roll may be cut from the bag roll
thereby creating a partially formed bag having opposing ends that
are unsealed. Sealing one end of a partially formed bag forms a
vacuum packaging bag with an opening at the other end.
[0011] An advantage of the present invention is that the
configuration of ridges of an embossed pattern allows gas to flow
around blockages through alternative paths. Moreover, a patterned
vacuum packaging film can be produced economically.
[0012] These and other advantages of the present invention will
become apparent to those skilled in the art after reading the
following descriptions and studying the various figures of the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 depicts a conceptual view of a vacuum packaging
film.
[0014] FIG. 2 depicts alternative vacuum packaging film patterns
for the vacuum packaging film depicted in FIG. 1.
[0015] FIG. 3 depicts a conceptual view of layers of a multi-layer
vacuum packaging film according to the present invention.
[0016] FIGS. 4A, 4B, 4C, and 4D depict exemplary systems for
manufacturing vacuum packaging film in accordance with the present
invention.
[0017] FIG. 5 depicts a flowchart illustrating an exemplary method
for manufacturing vacuum packaging film in accordance with the
present invention.
[0018] FIG. 6 depicts a vacuum packaging bag roll made of vacuum
packaging film according to the present invention.
[0019] FIG. 7 depicts a vacuum packaging bag made of vacuum
packaging film according to the present invention.
[0020] FIG. 8 is a conceptual view of a cross-section of a vacuum
packaging film according to the present invention.
[0021] FIG. 9 depicts a conceptual view of a cross-section of a
vacuum packaging film with a channel for evacuation according to
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The present invention provides a new embossed pattern for a
surface of a vacuum packaging film. The term embossed, as used
herein, is intended to mean that a pattern is raised or in relief
and is not intended to imply a particular technique--such as
cold-pressing, extrusion, or imprinting--used to apply the pattern.
The embossed pattern is operable to form channels suitable for
evacuation of gas from a vacuum packaging bag made of the film. The
pattern, due to its advantageous configuration, should reduce the
relative concentration and height of embossed ridges on the surface
of the film. In an embodiment, the embossed pattern includes a
plurality of roughly parallel sequences of substantially collinear
ridges, where ridges of a first sequence are offset with respect to
ridges of an adjacent second sequence. The offset ridges are
operable to form multiple channel paths through which gas flows
during evacuation of the vacuum packaging bag. Due to the offset,
if a channel becomes clogged or collapsed, gas will seek one of
many other alternative paths. The vacuum packaging film and an
exemplary method for manufacturing the film will now be described.
It should be noted that certain extraneous details were left out of
the subsequent description in an effort to not unnecessarily
obscure the true spirit and scope of the present invention.
[0023] FIG. 1 depicts a conceptual view of a vacuum packaging film
100. The vacuum packaging film includes a plurality of ridges 102
arranged as a plurality of sequences of collinear ridges 104. The
sequences of collinear ridges 104 are parallel to one another. In
addition, the ridges 102 of adjacent sequences of collinear ridges
104 are offset with respect to one another. This offset facilitates
rerouting of gas when the ridges 102 form walls of an evacuation
channel. Consider, for example, a gas flow 110. If the gas flow 110
encounters a blockage, the gas flow 110 can seek alternative routes
to the left or right of the blockage. In the example of FIG. 1, the
gas flow 110 flows to the right for illustrative purposes only.
[0024] FIG. 2 depicts alternative vacuum packaging film patterns
for the vacuum packaging film 100 (FIG. 1). FIG. 2 depicts a zigzag
pattern 200A, an alternative zigzag pattern 200B, and a wavy
pattern 200C. It should be noted that ridges 202 of a sequence 204
may be only approximately collinear. For the purposes of this
application, for any set of ridges, if each of the ridges intersect
a given line, then the ridges are referred to as "substantially
collinear" along the line. Accordingly, the sequence 204 may be
described as a sequence of substantially collinear ridges. It
should further be noted that some of the ridges of a first series
of substantially collinear ridges are not necessarily parallel to
the ridges of a second series of substantially collinear ridges.
Nevertheless, for the purposes of this application, for any given
series of sequences of substantially collinear ridges, if the lines
along which the substantially collinear ridges align are parallel
to one another, the sequences are referred to as "roughly
parallel." Accordingly, the sequences of substantially collinear
ridges of FIG. 2A may be described as roughly parallel.
[0025] The alternative zigzag pattern 200B and wavy pattern 200C
are analogous to the zigzag pattern 200A so they are not described
in detail herein. Moreover, it should be noted that the patterns of
FIG. 2 are depicted for exemplary purposes only. A great many
different roughly parallel sequences of ridges with an offset would
fall within the scope of this aspect of the present invention.
Similarly, an uneven pattern (not shown) of ridges could have the
effect of providing alternate routes if a channel is blocked.
[0026] FIG. 3 depicts a conceptual view of exemplary layers of a
vacuum packaging film 100 according to the present invention. The
vacuum packaging film 100 includes a structural layer 302, a
bonding layer 304, a gas-impermeable layer 306, a bonding layer
308, and a hear-sealable resin layer 310. The structural layer 302
provides strength to the multi-layer film. The bonding layer 304
bonds the structural layer 302 to the gas-impermeable layer 306.
The gas-impermeable layer may be made of polyester, polyamide
(nylon) or some other material that serves as an oxygen barrier to
protect the contents of a sealed bag made from the vacuum packaging
film 100. A bonding layer 308 bonds the gas-impermeable layer 306
to the heat-sealable resin layer 310. The heat-sealable resin layer
310 may be made of a polyethylene resin or any other heat-sealable
material that is food safe. In an embodiment, the heat-sealable
material must be food safe because it forms the inner layer of a
bag used to store food. In an alternative embodiment, the
heat-sealable material need not be food safe.
[0027] It should be noted that the vacuum packaging film 100 could
be made with as few as two layers, a gas-impermeable layer and a
heat-sealable resin layer, bonded together without a bonding layer
between them. The bonding layers and structural layer are optional
in this embodiment. Moreover, in an alternative, the heat-sealable
resin layer could be replaced with any sealable material, such as
glue.
[0028] FIGS. 4A, 4B, 4C, and 4D depict exemplary systems for
manufacturing vacuum packaging film in accordance with the present
invention. FIG. 4A illustrates an apparatus 400A for manufacturing
vacuum packaging film in accordance with an embodiment of the
invention. The apparatus 400A includes a multi-layer extruder 402
that extrudes a plastic melt 404 onto a roller 406, which may be a
cooling roller. The roller 406 is embedded with an inverse pattern
that turns in the direction of arrow 408. The inverse pattern is
for imprinting a pattern onto the plastic melt 404. As the
multi-layer extruder extrudes the plastic melt 404, the plastic
melt 404 comes in contact with the turning roller 406. As the melt
is cooled, a pattern is formed on the melt at the same time due to
the presence of the inverse pattern. As a result, a multi-layer
vacuum packaging film 410 emerges.
[0029] FIG. 4B illustrates an apparatus 400B for manufacturing
vacuum packaging film in accordance with an embodiment of the
invention. The apparatus 400B is much like the apparatus 400A (FIG.
4A), but includes a cooling plank 422. Instead of the multi-layer
extruder 402 extruding plastic melt 404 directly onto the roller
406, the multi-layer extruder 402 extrudes plastic melt 404 onto
the cooling plank 422. The cooling plank 422 has an inverse
pattern. As the plastic melt 404 flows along the cooling plank 422,
the plastic melt 404 congeals and is simultaneously imprinted with
a pattern, due to the presence of the inverse pattern. The
congealed plastic flows onto the roller 406, and a multi-layered,
patterned vacuum packaging film 410 emerges as it is pulled along
by the roller 406, which may or may not also have an inverse
pattern.
[0030] FIG. 4C illustrates an apparatus 400C for manufacturing
vacuum packaging film in accordance with an embodiment of the
invention. The apparatus 400C is much like the apparatus 400A (FIG.
4A), but includes an air knife 432. As the plastic melt 404 flows
onto the roller 406, the air-knife 432 selectively etches a pattern
onto the melt 404 with concentrated blasts of air 434.
Additionally, blasts of air 434 also cause the melt 304 to congeal
into multi-layered, patterned vacuum packaging film 410 that is
pulled along by the roller 406.
[0031] FIG. 4D illustrates an apparatus 400D for manufacturing
vacuum packaging film in accordance with an embodiment of the
invention. The apparatus 400D is much like the apparatus 400A (FIG.
4A), but includes an inverse vacuum 442. As the plastic melt 404
flows onto the roller 406, the inverse-vacuum 442 selectively
"pulls" a pattern onto the melt. Additionally, the inverse vacuum
442 also causes the melt to congeal into multi-layered, patterned
vacuum packaging film 410 that is pulled along by roller 406.
[0032] FIG. 5 depicts a flowchart 500 illustrating an exemplary
method for manufacturing vacuum packaging film in accordance with
the present invention. The flowchart starts at block 502 with heat
extruding a first material onto a roller. The flowchart ends at
block 504 with heat extruding a second material onto the roller
such that the first and second extruded materials bond and form a
film of the first material with multiple roughly parallel sequences
of substantially collinear ridges of the second material forming a
pattern that is operable to form channels suitable for evacuation
of gas from a vacuum packaging bag made of the film.
[0033] It should be noted that the method of manufacture using a
multi-layer extruder 402 is for illustrative purposes only. While
the manufacturing technique can produce a vacuum packaging film
with the advantageous qualities described herein, some other
technique for imprinting a pattern onto a vacuum packaging film
will also suffice, as is well-known in the art of vacuum packaging
film manufacturing. It should further be noted that, depending on
the technique for imprinting the pattern, a multi-layer vacuum
packaging film may have the pattern imprinted on one or more of the
multiple layers, or the pattern may simply be embossed only on the
heat-sealable resin layer.
[0034] FIG. 6 depicts a vacuum packaging bag roll 600 made of
vacuum packaging film 100 according to the present invention. The
vacuum packaging bag roll 600 includes a first sheet 602 of vacuum
packaging film 100 bonded to a second sheet 604 of vacuum packaging
film 100 on opposing lateral sides 606. The second sheet 604 has a
footprint that is substantially similar to the footprint of the
first sheet 602 so that the sheets fit together. The first sheet
602 and second sheet 604 are arranged with respective heat-sealable
resin layers 310 (FIG. 3) facing one another. Accordingly, the
heat-sealable resin layer 310 may be referred to as the inner layer
of a bag roll. Similarly, the structural layer 302 (FIG. 3) may be
referred to as the outer layer of a bag roll. Portions of the
vacuum packaging bag roll 600 can be cut from the bag roll thereby
creating a partially formed bag having opposing ends that are
unsealed.
[0035] FIG. 7 depicts a vacuum packaging bag 700 made of vacuum
packaging film 100 according to the present invention. The vacuum
packaging bag 700 includes a first sheet 702 of vacuum packaging
film 100 bonded to a second sheet 704 of vacuum packaging film 100
on opposing lateral sides and an end side 706. The first and second
sheets form the vacuum packaging bag 700 with an opening for
insertion of food or other product. In an embodiment, the vacuum
packaging bag is heat-sealable at the opening.
[0036] FIG. 8 is a conceptual view 800 of a cross-section of a
vacuum packaging film 100 according to the present invention. In
the example of FIG. 8, the embossed pattern, as exemplified by the
ridge 102, is imprinted on the gas-impermeable layer 306 and the
heat-sealable resin layer 310. As discussed earlier, the vacuum
packaging film 100 could be made with additional layers, such as
the bonding layer 308 (FIG. 3), some or all of which could also be
imprinted with the embossed pattern.
[0037] FIG. 9 depicts a conceptual view 900 of a cross-section of a
vacuum packaging film 100 with a channel 910 for evacuation
according to the present invention. A sheet 902 is placed against
the packaging film 100 such that the embossed ridges of the vacuum
packaging film 100 form walls of the channel 910. The sheet 902 may
or may not have the same embossed pattern as the vacuum packaging
film 100, but an embossed pattern is omitted from FIG. 9 for
illustrative purposes only. The heat-sealable resin layer 310 is
the inner layer and the gas-impermeable layer 306 is the outer
layer, also for illustrative purposes only.
[0038] While this invention has been described in terms of certain
embodiments, it will be appreciated by those skilled in the art
that modifications, permutations and equivalents thereof are within
the inventive scope of the present invention. It is therefore
intended that the following appended claims include such
modifications, permutations and equivalents as fall within the true
spirit and scope of the present invention. Moreover, the
embodiments described herein are for exemplary purposes only and
should not be construed to capture every embodiment of the
invention. The invention is limited only by the claims.
* * * * *