Note: Descriptions are shown in the official language in which they were submitted.
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Side-gusseted bag made of film
The invention concerns a side-gusseted bag according to the preamble of
claim 1. Side-gusseted bags of film, in particular plastic film, that are
embodied in circumferential direction of two main walls and two intermediately
positioned side-gusseted walls and are delimited at the top side and bottom
side by transverse seams or reclosure devices are widely used in daily life. A
side-gusseted bag for receiving pasty or liquid substances, even though with
incompletely formed side gussets, is disclosed in EP 1 362 797 B1 wherein
the bag at the topside is closed off by a transversely extending head seam
into which a spout in the form of a cap closure is sealed. Spouts of this kind
typically comprise a weld-in or seal-in region in which opposite fastening
surfaces enable a fold-free contact of the film and an attachment that
provides a load-resistant and seal-tight closure.
The type of the side-gusseted bag disclosed in the aforementioned
publication is designed to provide transitions between the bag of film and the
spout that are free of folds as much as possible. Even though, the known
bag, due to its rectangular basic shape, tends to form a filling shape with
gusset-shaped or pocket-shaped areas that counteract filling without air
inclusions and emptying without liquid residues.
On the other hand, there is a significant interest in film packagings that are
material-saving and are inert with regard to the liquid filling, that can be
filled
and emptied completely and without problems. Such containers are
conceivable as individual containers as well as in the form of linings or
inner
bags for enclosing containers of the solid type, such as cardboard, wood or
sheet metal containers, in which the inner container can be emptied by being
collapsed and optionally also ensures exclusion of air in this context. This
is
utilized, for example, in connection with wine containers that with a large
fill
volume and correspondingly long emptying periods avoid detrimental effects
on the wine due to exposure to air. At the same time, there is an interest in
designing the manufacture of such side-gusseted bags by means of
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machines so as to be reliably moisture-tight and breakage-safe and in
particular also inexpensive.
It is therefore the object of the invention to redesign a side-gusseted bag as
a
closed container provided with a spout such that, as a liquid container, it is
suitable for complete filling and complete emptying while, at the same time,
it
can be produced by conventional manufacturing methods and in
manufacturing machines in an uncomplicated, fast and breakage-safe way,
wherein the shape should also be collapsible to a flat state for a compact
arrangement for shipping and storage.
According to the invention, this object is solved by a side-gusseted bag,
based on the preamble of claim 1, with the characterizing features of claim 1.
While the conventional four-sided side-gusseted bag is designed to obtain,
upon filling, for example, with grainy material, a parallelepipedal shape
that,
however, upon filling with liquid would bulge and distort and also generate
corners and pockets, an increase in the number of sides is already suitable to
provide a multi-sided polygon shape and thus a better approximation to a
desired rounding of the circumference. In comparison to a four-sided or
square cross-section, already a pentagon cross-sectional shape matches
much better a circular shape that is formed at least in approximation due to
interior pressure of a liquid. The increase of surfaces is achieved by a
greater
number of side-gusseted walls that, as in the conventional four-sided
side-gusseted bag, can assume a flat arrangement with main surfaces and
intermediately folded-in sidewalls.
In this context, an increase of the number of sidewalls for reasons of simple
two-sided manufacture as well as uniform folded position of the side-gusseted
bag, two side-gusseted walls each underneath each side of the main walls
will be preferred in order to achieve a better rounding with a hexagon
cross-sectional shape as compared to a pentagon cross-sectional shape. In
the same sense, even higher wall numbers can be provided also whereby
however the manufacturing expenditure then also becomes greater without
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the approximation of the polygonal contour to a round cross-section being
increased equally.
Slanted seams between the side-gusseted walls among each other or
between the side-gusseted walls and the main walls that provide at least the
head region on the inner side with a geometry in the form of a smooth cover
wall contribute significantly to avoiding accumulations or pockets upon
filling
or emptying of such a side-gusseted bag. For adaptation to a container with
flat bottom and top surfaces, such a cover wall can be predetermined to be
planar. However, it is also possible with smaller angles of the slanted seams
relative to the longitudinal direction to orient the configuration of the
inner
shape in the head region to extend conically toward the spout in order to
ensure a complete and easy inflow and outflow.
US 7,147,597 B2 discloses already side-gusseted bags with (three or) five
circumferential sides which however are not collapsible to a flat and smooth
state. Here, all slanted seams in the head region are oriented toward a single
center point in order to connect a spout with all circumferential sides. These
connections cannot be produced easily on a machine and lead to wall
transitions that cannot be folded in so as to be free of wrinkles.
A side-gusseted bag according to the invention made of film can be produced
in a particularly simple way by means of sealed seams when the film as a
whole is sealable or is provided at least on one side with a sealable layer.
Conventionally used and well suited in this context is a composite film with a
polyolefin film, in particular polyethylene, as an inner layer that provides
excellent sealability on the inner side and an outer layer of polyester which
is
usually thinner, stronger, and is also melting at higher temperature. This
material combination has also the further advantage, widely used in practice,
that the sealed seams between the side-gusseted walls among each other
and between the side-gusseted walls and the main walls can be sealed, while
resting on each other, through several films in one single working step
without
thereafter the outer sides being fused together and preventing unfolding of
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the bag from its flat position into the fill position.
It is understood, of course, that, depending on the requirements in regard to
seal-tightness and chemical resistance, also adhesively connectable or
fusible metal films or also composite films with a metal layer can be employed
instead of the plastic composite film.
Manufacture of such a side-gusseted bag is possible on machines that
manufacture already conventional side-gusseted bags with two main walls
and only two side-gusseted walls positioned individually therebetween.
Manufacture is first directed at a hose (circumferentially closed) that can be
produced in that a single film web has the oppositely positioned lateral edges
combined and closed by a single longitudinal seam to form a hose, but also,
in an alternative conventional embodiment, in that the main walls and the
side-gusseted walls as strips are combined and connected to each other by
several longitudinal seams to form a hose. In conventional side-gusseted
bags, slanted seams as support seams have already been used partially at
45 relative to the longitudinal direction which, however, usually did not
delimit
the side-gusseted walls but only shape them internally. For a large number of
side-gusseted walls according to the invention, the slanted seams extend
however typically at an angle of less than 45 relative to the longitudinal
direction.
The more precise determination of the angle is realized with respect to
whether a flat planar head region, for adaptation to an enclosing container
with a flat top side, or a funnel-shaped head region for better complete
filling
and emptying is to be provided. In case of the flat planar head design the
slanted seams of the unfolded side walls and main walls in the head plane
form triangles that combine to a planar surface. In deviation from a uniform
division of a pentagon, hexagon, or polygon by identical inwardly converging
triangles, it must be taken into consideration that two oppositely positioned
walls are to abut not with a point but with an at least short head seam into
which also the spout is to be incorporated. Accordingly, typically two larger
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triangles with a cut-off tip for the head seam are to be provided opposite
each
other which usually are provided for the main walls wherein the slanted
seams begin to diverge only from the two ends of the head seam.
The afore described configuration basically also applies to an embodiment of
the side-gusseted bag that is conical or funnel-shaped in the head region
wherein the triangular shapes of the walls wipe the slanted seams are all the
more pointed the more pronounced the conical shape is to be designed.
Aside from all the freedom of design, a configuration of the side-gusseted
walls with identical circumferential width relative to each other is
particularly
self-evident where the neighboring side-gusseted walls in the folded-in state
also are positioned congruently on top of each other while the main walls
have a width that is longer by the length of the head seam.
The main walls and the side-gusseted walls can be provided with longitudinal
seams between each other when manufacture of the side-gusseted bag is
based on a single film web and therefore only a single longitudinal seam
would have to be provided. Longitudinal seams between the main walls and
the side-gusseted walls or between the side-gusseted walls among each
other can however be expedient for stiffening the bag and for a controlled
collapse upon emptying. Preferably, the longitudinal seams are then provided
as fin seams that project outwardly. This makes it possible to keep the inner
side of the side-gusseted bag smooth and without unnecessarily wetted
surfaces. The fin seams which are projecting outwardly are desirable also for
side-gusseted bags to be used as inner container and which thereby
counteract an undesirable adhesion of the inner container on the exterior
container.
The configuration of a bottom region, that is oppositely position to the head
region at the bottom, can be realized with very similar considerations wherein
however a central head seam is not needed because at the bottom usually no
spout or other emptying opening must be provided. Accordingly, also in the
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bottom area acute-angled triangles can be provided between slanted seams.
Preferably, the bottom area in consideration of a smooth collapse of the bag
is designed congruent with the head region. The "congruent" configuration of
the bottom area relative to the head region does not prevent to design indeed
the bottom to be flat when the head region is conically extended, and vice
versa. The usual terms of "head" or "bottom" relate theoretically to a (fill)
position with spout at the topside even when the bag for emptying must be
positioned upside down.
Two embodiments of the invention are illustrated in the drawing and will be
explained in the following in more detail. The drawing shows in:
Fig. 1 side view of a first embodiment (partially broken),
Fig. 2 plan view of the embodiment according to Fig. 1,
Fig. 3 cross-section of the embodiment of Fig. 1 and Fig. 2 at the beginning
of
folding,
Fig. 4 enlarged detail IV of Fig. 3,
Fig. 5 cross-section of the side-gusseted bag in folded state,
Fig. 6 plan view of the folded state according to Fig. 5, and
Fig. 7 side view of a second embodiment of the side-gusseted bag.
In Fig. 1 and Fig. 2 a side-gusseted bag according to the invention in
unfolded
state is identified with 1. It has a hexagon contour comprised of six walls
that
in regard to width to not deviate or only insignificantly deviate from each
other, which adjoin each other in the circumferential direction and converge
toward a head region 2 as well as toward a bottom 3 toward the center. The
head region is provided with a spout 4 at the center.
The side-gusseted bag 1 is embodied of a film that is sealable at the inner
side, in the present case a plastic composite film with a polyethylene (PE)
inner layer and a polyester (PET) outer layer. Into this film, the spout 4 is
sealed seal-tightly and fixedly into a head seam 5 by means of two oppositely
positioned sealing surfaces as fastening surfaces. The illustrated spout can
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be closed by a screw cap, but of course could also be provided with a stopper
or another closure.
The side-gusseted bag 1 that unfolds substantially to a drum shape has a
hexagon contour for filling with liquid, where upon it approximates a
cylindrical
shape, formed by side walls joined to each other which in the head region 2
and at the bottom 3 similar to pie slices converge toward the center. However,
they do not meet at a single central point but meet at one of two ends,
respectively, of the head seam 5 that enables the two-sided sealing of a
spout. The head seam 5 is formed between the upper cut-off triangular tips of
two walls 6, 7 that are provided somewhat wider than the other walls 8, 9, 10,
11 in order to adjust the geometry of the lateral lengths and angles relative
to
each other. In principle, however, sides of the same circumferential width can
be provided also as long as in the head region the arrangement of a spout is
ensured.
Fig. 3 shows the sides 8, 9, 10, 11 extending parallel and slightly bent to a
longitudinal direction that is to be imagined to extend centrally from the
bottom 3 to the head region. This indicates that these walls are to be
understood as side-gusseted walls that enable folding of the side-gusseted
bag as in case of conventional side-gusseted bags with four walls. In this
way,
not only space-saving stacking and shipping are provided but also a flat
manufacturing procedure, for example, from a single film web that is joined
with the oppositely positioned edges and sealed together in the longitudinal
direction or a manufacturing procedure from strips which are joined in the
width of the respective walls and then are sealed together by seams.
In the first case, in which first a hose shape of a single film web is
produced,
longitudinal seams at the circumference, aside from a single hose-forming
seam, are not mandatory. At the same time, in particular the enlarged
illustration according to Fig. 4 shows a willfully sealed-in longitudinal seam
12
between the side-gusseted wall 9 and the wider wall 7 which has been
incorporated for reinforcement and contour shaping and requires no seal-tight
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sealing because the film at this location extends continuously without a cut
and is provided only with a fixed reinforcement fold.
Fig. 5 shows the side-gusseted bag 1 in a folded state in which the wider
walls 6 and 7 as main walls are laid flat and the side-gusseted walls 8, 9,
10,
11, folded in longitudinal direction approximately at half the width, are
positioned there between . Since the main walls 6, 7 are wider than the
side-gusseted walls 8, 9, 10,11 that among each other have the same width,
the side-gusseted walls folded in half will not meet at the center but remain
spaced apart continuously along the fold lines 21, 22 indicated in Fig. 6.
Fig. 6 shows the folded form of the side-gusseted bag 1 in a flat plan view
with main surface 6 at the top whose parallel lateral edges 13, 14 extend in
longitudinal direction according to arrow 15 in Fig. 1 and thereat are
reinforced with parallel laterally projecting seams 15, 16. The seams 15, 16
converge toward the head seam 5 with slanted seams 17, 18 that, for a
hexagon side-gusseted bag of the type considered here, can be seen on the
outline of an approximately equilateral triangle. The bottom 3 forms in the
folded form according to Fig. 5 and Fig. 6 also a triangular shape wherein a
bottom seam 19 (without spout) provided to be congruent with the head seam
5 is provided for symmetry reasons so that parallel fold lines and congruent
seams will result. The folded form according to 5 and 6 forms thus a "packet"
with fold lines and seams that are stacked on each other. It is understood of
course that willful modifications are possible indeed in order to displace,
for
example, the fold lines and the seams in the folded state relative to each
other when this is preferred for better distribution of fold lines or seams.
The afore described embodiment of the type of a "drum" with flat bottom and
head region is particularly in demand for applications in which such a
side-gusseted bag as "inliner" is to be inserted into a more stable enclosing
container of cardboard, wood or sheet metal that also can be filled well with
a
hexagon side-gusseted bag for providing a round cylindrical inner shape.
Even a pentagon shape has already significant adaptation advantages
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relative to a conventional side-gusseted bag with four circumferential
surfaces. On the other hand, it is apparent that, if desired, also a polygon
form with more surfaces can be conceptualized and produced along the same
lines.
Seams that are projecting outwardly like fins such as the seam 12 in Fig. 4
have been found to be advantageous not only for contour shaping of the fold
lines and for reinforcement of the side-gusseted bag but also aid in
preventing inner adhesion of the film of the side-gusseted bag in case of
enclosing containers that have a smooth inner surface.
In Fig. 7 a variant of the side-gusseted bag is indicated as a whole at 22, in
which two side-gusseted walls 23 and 24 illustrated in the drawing are shown
with a fin seam 25 between each other and with fin seams 26, 27 relative to
adjoining main walls (not illustrated), wherein the side-gusseted walls 23, 24
as well as the other side-gusseted walls and the main walls in a head region
28 and at a bottom 29 converge toward the center in a funnel shape. This is
of interest in case of liquid-filled side-gusseted bags in particular in the
head
region 28 in order to facilitate complete filling and complete emptying. Such
a
bag is to be designed to be foldable in the same way to a flat state like the
side-gusseted bag according to Figs. 1 through 6wherein only between the
slanted seams such as the slanted seams 30, 31 elongate triangular end
areas of the main walls and side-gusseted walls with narrower angles
between the seams are provided. For these angles, again a head seam 32 is
to provided into which a spout 33 is to be embedded from two sides in order
to furnish the film of the side-gusseted bag with a solid injection-molded
filling
and pouring component.
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