Package making – Progressively seamed cover web or web folds – With closing of web between package units
Reexamination Certificate
2002-04-30
2004-01-20
Sipos, John (Department: 3721)
Package making
Progressively seamed cover web or web folds
With closing of web between package units
C493S248000, C493S256000, C493S418000, C053S201000
Reexamination Certificate
active
06679034
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a vertical stand-up pouch and a flat bottom bag having vertical gussets constructed using a modified vertical form, fill, and seal packaging machine, and the method for making same, that provides for a single piece construction of a stand-up bag suitable for retail snack food distribution. The invention allows for use of existing film converter and packaging technology to produce a stand-up package with minimal increased costs and minimal modifications.
2. Description of Related Art
Vertical form, fill, and seal packaging machines are commonly used in the snack food industry for forming, filling, and sealing bags of chips and other like products. Such packaging machines take a packaging film from a sheet roll and forms the film into a vertical tube around a product delivery cylinder. The vertical tube is vertically sealed along its length to form a back seal. The machine applies a pair of heat-sealingjaws or facings against the tube to form a horizontal transverse seal. This transverse seal acts as the top seal on the bag below an d the bottom seal on the package being filled and formed above. The product to be packaged, such as potato chips, is dropped through the product delivery cylinder and formed tube and is held within the tube above the bottom transverse seal. After the package has been filled, the film tube is pushed downward to draw out another package length. A transverse seal is formed above the product, thus sealing it within the film tube and forming a package of product. The package below said transverse seal is separated from the rest of the film tube by cutting horizontally across the sealed area.
The packaging film used in such process is typically a composite polymer material produced by a film converter. For example, one prior art composite film used for packaging potato chips and like products is illustrated in
FIG. 1
, which is a schematic of a cross-section of the film illustrating each individual substantive layer.
FIG. 1
shows an inside, or product side, layer
16
which typically comprises metalized oriented polypropylene (“OPP”) or metalized polyethylene terephtalate (“PET”). This is followed by a laminate layer
14
, typically a polyethylene extrusion, and an ink or graphics layer
12
. The ink layer
12
is typically used for the presentation of graphics that can be viewed through a transparent outside layer
10
, which layer
10
is typically OPP or PET.
The prior art film composition shown in
FIG. 1
is ideally suited for use on vertical form and fill machines for the packaging of food products. The metalized inside layer
16
, which is usually metalized with a thin layer of aluminum, provides excellent barrier properties. The use of OPP or PET for the outside layer
10
and the inside layer
16
further makes it possible to heat seal any surface of the film to any other surface in forming either the transverse seals or back seal of a package. Alternatively, a material can be used on the outside layer
12
that will not seal on itself, such as a paper layer or a non-sealing polymer layer, so that only the inside layer
16
is used as a sealing surface.
Typical back seals formed using the film composition shown in
FIG. 1
are illustrated in
FIGS. 2
a
and
2
b
.
FIG. 2
a
is a schematic of a “lap seal” embodiment of a back seal being formed on a tube of film, which can be used when the outside and inside layers are sealable together.
FIG. 2
b
illustrates a “fin seal” embodiment of a back seal being formed on a tube of film, which can be used when the outside layer is not suitable as a sealing surface.
With reference to
FIG. 2
a
, a portion of the inside metalized layer
26
is mated with a portion of the outside layer
20
in the area indicated by the arrows to form a lap seal. The seal in this area is accomplished by applying heat and pressure to the film in such area. The lap seal design shown in
FIG. 2
a
insures that the product to be placed inside the formed package will be protected from the ink layer by the metalized inside layer
26
.
The fin seal variation shown in
FIG. 2
b
also provides that the product to be placed in the formed package will be protected from the ink layer by the metalized inside layer
26
. Again, the outside layer
20
does not contact any product. In the embodiment shown in
FIG. 2
b
, however, the inside layer
26
is folded over and then sealed on itself in the area indicated by the arrows. Again, this seal is accomplished by the application of heat and pressure to the film in the area illustrated.
Regardless of whether a lap seal or fin seal is used for constructing a standard package using a vertical form and fill packaging machine, the end result is a package as shown in
FIG. 3
a
with horizontally oriented top and bottom transverse seals
31
,
33
. Such package is referred to in the art as a “vertical flex bag” or “pillow pouch,” and is commonly used for packaging snack foods such as potato chips, tortilla chips, and other various sheeted and extruded products. The back seal discussed with reference to
FIGS. 2
a
and
2
b
runs vertically along the bag and is typically centered on the back of the package shown in
FIG. 3
a
, thus not visible in
FIG. 3
a
. Because of the narrow, single edge base on the package shown in
FIG. 3
a
formed by the bottom transverse seal
33
, such prior art packages are not particularly stable when standing on one end. This shortcoming has been addressed in the packaging industry by the development of a horizontal stand-up pouch such as the embodiment illustrated in
FIGS. 4
a
,
4
b
, and
4
c
. As can be seen by reference to said figures, such horizontal stand-up pouch has a relatively broad and flat base
47
having two contact edges. This allows for the pouch to rest on this base
47
in a vertical presentation. Manufacture of such horizontal stand-up pouches, however, does not involve the use of standard vertical form, fill, and seal machines but, rather, involves an expensive and relatively slow 3-piece construction using a pouch form, fill, and seal machine.
Referring to
FIGS. 4
b
and
4
c
, the horizontal stand-up pouch of the prior art is constructed of three separate pieces of film that are mated together, namely, a front sheet
41
, a rear sheet
43
, and a base sheet
45
. The front sheet
41
and rear sheet
43
are sealed against each other around their edges, typically by heat sealing. The base sheet
45
is, however, first secured along its outer edges to the outer edges of the bottom of the front sheet
41
and rear sheet
43
, as is best illustrated in
FIG. 4
c
. Likewise, the mating of the base sheet
45
to the front sheet
41
and the rear sheet
43
is also accomplished typically by a heat seal. The requirement that such horizontal stand-up pouch be constructed of three pieces results in a package that is significantly more expensive to construct than a standard form and fill vertical flex bag.
Further disadvantages of using horizontal stand-up pouches include the initial capital expense of the horizontal stand-up pouch machines, the additional gas flush volume required during packaging as compared to a vertical flex bag, increased down time to change the bag size, slower bag forming speed, and a decreased bag size range. For example, a Polaris model vertical form, fill, and seal machine manufactured by Klick Lock Woodman of Georgia, USA, with a volume capacity of 60-100 bags per minute costs in the range of $75,000.00 per machine. A typical horizontal stand-up pouch manufacturing machine manufactured by Roberts Packaging of Battle Creek, Mich., with a bag capacity of 40-60 bags per minute typically costs $500,000.00. The film cost for a standard vertical form, fill, and seal package is approximately $0.04 per bag with a comparable horizontal stand-up pouch costing roughly twice as much. Horizontal stand-up pouches further require more than twice the oxygen or nitrogen gas flush. Changing the bag size on a horizontal stand-up pouch further takes in excess of two
Kohl Garrett William
Tucker Steven Kenneth
Cahoon Colin P.
Carstens Yee & Cahoon, L.L.P.
Recot Inc.
Sipos John
LandOfFree
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