Note: Descriptions are shown in the official language in which they were submitted.
i
Abstract o~ the Disclosure
Containers formed of a flexible sheet of ma~erial
capable of being sealed for closiny off the interior of the
container from the ambient atmosphere. The sheet material is
resistant to tearing and includes an inner surface and an
outer surface. The container comprises a mouth portion in-
cluding a peel strip or layer fixedly secured to the inner
surface of the material and extending substantially the entire
length of the mouth por-tion, with adjacent portions of the
peel strip or layer being in releaseable engagement with each
other. The engagement forms an air-tight interfacial seal at
the mouth which is readily openable by peeling the engaging
portions of the peel strip or layer from each other to provide
ready access to the interior of the container wi-thout tearing
the sheet material forming the container. Thus, the container
can be readily reclosed by conventional mechanical means, such
as folding t tin ties, etc.
SPECIFICATION
This invention relates generally to containers and,
more particularly, to containers formed of flexible sheet
materials.
Flexible containers formed of sheet materials have
been used for several years and are now gaining ever wider
acceptance for holding various air-perishable products, e.g.,
oodstuffs, etc. Prior art flexible~ air-tight containers are
commonly constructed of some plastic film, metal foil, or
combinations thereof, in one or more plies and sealed along
one or more seams. Such containers are usually vacuumized
after filling but prior to sealing so that the contents of the
container are not exposed to the degradation effects of air.
Accordingly, products held in such containers can have a shelf
life comparable to rigid containers, such as jars with
screw-on lids or metal cans.
The advantages of flexible containers over rigid
containers are many. For example, 1exible containers can be
manufactured at substantially lower cost and can be stored
flat, thereby resulting in enormous space savings over rigid
containers. Moreover, flexible containers are substantially
lighter in weight, thereby resultiny in reduced transportation
costs for unfilled containers. Further still, flexible
containers are generally of an overall parallelopiped shape
when filled so that such containers take up considerably less
shelf or storage space. Needless to say, this feature is oE
considerable importance insofar as transportation, storage,
and display are concerned.
While prior art air-tight, flexible containers
exhibit the aforementioned advantages over rigid containers,
they still have not proved a completely acceptable alternative
to hard containers for the air-tight storage of materials,
particularly when it is desired to be able to open and reclose
the container aEter its initial opening. In this regard, the
seams of prior art flexible containers are usually permanent
in the interest of air tightness and structural integrity and
are commonly formed by conventional heat sealing or welding
techniques. Thus, the prior art flexible container is opened
by cutting or tearing one or more of its seams. Owing to the
permanent nature of the sealed seams, the tearing of any seam
to gain access to the contents of the container not only
destroys the seal but frequently results in the tearing of the
material of the container contiguous with the seam. This is
an obviously undesirable result since it may render the
s
container useless for reclosure and continued holding of the
contents of the container. If the container is opened by
cutting off its top below the heat seal line, while the wall
portions forming the container are not torn (thus permitting
reclosure), the container is nevertheless shorter and thus of
lower volumetric capacity.
Various flexible packaging structures have been
disclosed in the prior art utilizing tear strips and/or tear
lines to facilitate opening of the container. Examples of
such patents are United States Patent Nos. 3,186,628 (Rohde),
3,535,409 (Rohde), and 3,939,972 (Mayworm).
In the United States Patent Re 3U,726 (Otten et al.),
there is disclosed a pouch c~nposed of an extruded polymer
film formed by a blend of polyethylene resin and an ionomer.
The pouch is formed by extruding the polyethylene/
ionomer blend into a continuous tubular film which exhibits a
linear tear property in the machine direction. By linear tear
property, it is meant that the material has the inherent
property to tear readily by hand along the substantially
straight line by a normal shearing or parting motion without
the need for guiding the tear. The tubular film is then slit
longitudinally, cut into transverse sections, and heat sealed
adjacent the transverse cuts to form a bag or pouch haviny an
open top end. After the pouch is filled, the open top end is
heat sealed to close the pouch. By virtue of the orientation
of the Eilm, the resulting pouch exhibits a linear tear
property across its top end. To facilitate the opening of the
pouch across its top, one edge of the pouch adjacent the top
is slit or nicked to provide a starter tear. Thus, opening of
the pouch is accomplished by tearing the top off of the pouch.
While such action may be effective to provide ready access to
the interior of the pouch, the tearing away of the top portion
of the pouch limits the pouch's utility for being reused and
reclosed at its top end.
OBJECTS OF THE INVENTION
Accordingly, it is the general object of the instant
invention to provlde a flexible material container and a
method o-f producing the same which overcomes the disadvantages
of the prior art.
It is a further object of the invention to provide a
flexible container having an air-tight sealed mouth but which
can be readily peeled open without resulting in the
destruction of any portion of the container, thereby enablng
the container to be reclosed.
It is still a further object of this invention to
provide a flexible container haviny a mouth which is sealed by
a peelable interface between abutting wall portions of the
container and which interface can be readily peeled open
without destroying any portion of the container~
It is still a further object of this invention to
provide a flexible container which is resistant to tearing or
opening at all portions thereof but which includes a ~outh
having an air-tight interfacial seal which can be readily
peeled open.
It is yet a further objec-t of this invention to
provide a method for producing a flexible container having an
air-tight sealed mouth which can be readily peeled open
without resulting in the destruction of any portion of the
container.
~Z~ 5
It is still a further object of this invention to
provide a simple and economically viable method of producing a
flexible container which is sealed by a peelable interface
between abutting wall portions of the container and which
interface can be readily opened without destroying any portion
of the container.
SUMMARY OF THE IN~ENTION
These and other objects of the instant invention are
achieved by providing a container and a method for making the
container. The container comprises a flexible sheet material
capable of being sealed for closing off the interior o the
container from the ambient atmosphere. The sheet material is
resistant to teariny and includes an inner surface and an
outer surface. The container comprises a mouth portion
including peel strip means fixedly secured to the inner
surface of the material and extending substantially the entire
length of the mouth portion. Adjacent portions of the peel
strip means are in releaseable engagement with each other to
form an air-tight interfacial seal at the mouth. The
interfacial seal is readily openable by peeling the engaging
portions of the peel strip means from each other to provide
ready access to the interior of the container without tearing
the sheet material forming the container.
DESCRIPTION OF THE D~AWING
-
Other objects and many of the attendant advantages of
this invention will be readily appreciated as the same becomes
better understood by reference to the following detailed des-
cription when considered in connection with the accompanying
drawings wherein:
-- 5 --
~4~ 5
Fig. 1 is a perspective view of an exemplary
embodiment of a container constructed in accordance with the
teachings of the subject invention;
Fig. 2 is an enlarged sectional view of a filled,
sealed container, like that shown in Fig. 1, and taken along
line 2-2 of Fig l;
Fig. 3 is a sectional view taken along line 3-3 of
Fig. 2;
Fig. 4 is an enlarged sectional view of a portion of
the container shown within the encircled area in Fig. 2î and
Fig. 5 is a perspective view, greatly simpliEied, of
a system for forming the container shown in Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in greater detail to the various
figures of the drawing where like reference characters refer
to like partsr there is shown generally at 20 in Fig. 1 the
container Eormed of a flexible sheet material constructed in
accordance with the instant invention.
The container 20 is formed of a sheet oE fle~ible
rnaterial, to be described later, and basically comprises a
front wall 22, a rear wall 24, a first gussetted sidewall 26,
a second gussetted sidewall 28, a bottam end 30, and a top end
32. The front wall 22, rear wall 24 and gussetted sidewalls
26 and 28 are all integral portions of a single sheet of
flexible material which has been folded and seamed as will be
described later.
In accordance with the subject invention, the flex-
ible material can be formed of any commercially available
flexible material heretofore used for forming flexible packag
ing. Examples of such materials are polyethylene, polyes-ter,
-- 6 --
~LZ~3~5
p~lypropylene, metal foil, and c~nbinations thereof in single
or multiple plies.
In the embodiment of the invention disclosed herein,
the sheet material forming the front wall 22, back wall 24,
and gussetted sidewalls 26 and 28 of the container 20 are
formed of cellophane-polyethylene. It must be pointed out at
~his juncture that such material ls merely exemplary and hence
other materials can be used depending upon the desired
characteristics for the container.
The exemplary embodiment of the sheet material form-
ing the bag 2U is shown in considerable detail in the section-
al view of Fig. 4. As can be seen therein, the sheet material
consists o~ two plies, namely, a cellophane ply 34 and a poly-
ethylene ply 36. The cellophane ply is coated on both sides
with polyvinylidene chloride. Thus, the outer surface oE cell-
ophane ply 34 includes a polyvinylidene chloride coating 38,
while the inner surface includes a polyvinylidene chloride
coating 40. The coated cellophane ply 34 is secured to the
polyethylene ply 36 via an interposed adhesive layer 42.
As can be seen in Fig. 1, the back wall 2g of the bag
20 includes a longitudinally extendiny (vertical) seam 44.
The seam 44 is formed by the marginal edges 46 and 48 of a
section of a web of the material forming the bag and which
edges are brought into engagement with one another. The edges
46 and 48 are permanently secured to one another via any
conventional sealiny technique, such as heat sealing, welding,
etc. The bottom end 30 of the bag is also sealed closed along
a permanent seam line 50. The seam line 50 is also formed
usiny conventional sealing techniques~ like that used for the
seam 44.
The resulting construction thus consists of a bag or
pouch-like container having an open top end or mouth 52. It
is through the open top end or mouth that the container is
filled.
In accordance with the subject invention, the con-
tainer 20 includes peel strip means 54, to be described in
considerable detail later, disposed adjacent the mouth for
sealing the mouth of the container to enclose the contents
therein and protect the contents from the ambient atmosphere.
The peel strip means serves as a mechanism which can be
readily peeled open without destroyiny the container to
provide ready access ~o the interior oE the container. Thus,
the container 20 of the subject invention can be reclosed
after its initial opening.
The containers 20 of the instant invention are
produced by one of two methods, namely, the manufacture,
filling, and sealing of the container in one operation by
mechanized equipment, or the manufacture of an empty and
Unsealed container which is then provided to the end user for
filling and subsequent sealing. Both of said methods are a
part of the subject invention and will be described in detail
later.
As can be seen in Fig. 1-4, the peel strip means 54
basically comprises a strip of material which is permanently
secured to the inside surface of the sheet material forming
the front wall, sidewalls, and back wall of the container 20.
The strip 54 is located adjacent the open mouth 52 and thus
extends about the entire inner periphery of the container
(with the exception of the marginal edges forming seam 44) and
is permanently secured thereto.
-- 8 --
:~4'~385
The strip means 54 is formed of any material which
can be secured to itself via heat sealing or welding to
provide an air~tight interface, but which can be readily
peeled apart at its interface without destroying the material
thereof. It has been found that a suitable plastic film
for the strip 54 consists of a hlend of polyethylene and
an ionomer like that sold by E.I. DuPont DeNemours &
Company under the Trademark "SURLYN 1601" such as described
in Reissue Patent No. 30,726 identified heretofore.
Other ionomers disclosed in said patent or other plastic
materials having similar characteristics to those disclosed
therein may also be used.
In a preferred embodiment of the subject invention,
the peel strip means 54 consists of a coextrusion (i.e.,
a two-laver construction), one layer being a polyethylene-
Surlyn blend and the other layer being polyethylene.
Thus, as can be seen in Fig. 4, the peel strip means 54
consists of inner ply 56 :Eormed of polyethylene and ou-ter
ply 58 formed of a blend of polyethylene-Surlyn. The
strip 54 completely encircles the inner surface of the
sheet material forming the container adjacent the
container's mouth 52 but does not extend into the seam
44 in -the interest of maintaining the integrity of the
seam when the container is later opened. The peel strip
54 is secured in place on the inner surface of the
container adjacent its mouth 52 via a pair of longitudinally
extending peripheral heat seals or welds 60. ~ach heat
seal or weld is located parallel and closely adjacen-t
the respective edge of the strip 54 and produced in a
conventional manner by means to be described later.
g
As should thus be appreciated, the completed
container as shown in Fig. 1 includes an inwardly directed
layer of a peelable polyethylene-Surlyn blend 58 adjacent its
mouth. The contiguous surface portions of the peelable layer
58 are disposed opposite each other for engagement wi-th each
other to seal the mouth of the container 20. Accordingly,
after the container is filled with the desired contents 62 and
then vacuumized to remove any air from the interior thereof,
the opposed peel strip surface portions 58 are brought into
engagement with each other (as shown in Figs. 3 and 4) and
heat sealed. This action causes the opposed strip portions 58
to become releaseably secured to one another at an air-tight
yet weakened interfacial seal 64 (Fig. 4). This in-terfacial
seal, while air-tight, can be readily peeled open without
damaginy the strips 56 or the material forming the container's
walls 22, 24, 26, and 28. Thus, all that is required to open
the container is to apply a force at the top end 32 tending to
separate the front wall 22 from the rear wall 24. This action
causes the abutting peelable surfaces 58 to readily peel away
froln each other along the interface 64 in a clean opening and
without in any way damaging the walls of the container.
Accordingly, one can readily gain access to the interior
contents 62 of the container 20. Moreover, inasmuch as the
container is intact, albeit open, one can readily reclose the
bag (although not with an air-tight seal), by merely bringing
the mouth's wall surfaces 22, 24, 26, and 28 into engagement
with one another, folding the top edge of those surfaces over
and holding the folded edges in place with mechanical means,
e.g., a tin tie (not shown) which can be incorporated into the
container's walls adjacent the mouth.
-- 10 --
3 ~ ~
In accordance with the preferred embodiment of the
invention, the peelable strip means S4 is located a
substantial distance below the top of the container to provide
the fold or mechanical securement area Eor reclosure of the
container after the peel strip 54 has been opened.
In Fig. 5 there is shown, in schematic form,
apparatus for producing containers constructed in accordance
with the instant invention. Accordingly, the container-making
system comprises a roll 100 of the sheet material forming the
containers' walls. The material is reeled ofE the roll in a
web 102, which web is carried longitudinally in the direction
of arrow 104 past a peel strip application station 106. The
peel strip application station 106 forms only one portion of
the entire container-forming system (not shown) and is
arranyed to apply a plurality of peel strips 54 (like that
disclosed heretofore) at equidistantly spaced locations along
the web 102 passing thereby. As can be seen in Fig. 5, each
strip 54 extends Eor substantially the entire width of the web
102 except for a marginal edge portion 108 on each side of the
strip. The marginal edge portion form the edge portions 46
and 48 of the container's vertical seam 44 (as described
heretofore).
Each strip 54 is secured to the web 102 by heat
sealing it along the parallel heat seal line 60 at station
1060 The web is then severed across its -full width at a cut
line 110. The cut line 110 serves to divide the web 102 into
plural sections 112, each of which is thereafter formed
(folded) into the container 20. Thus, the cut line 110 forms
the top edye 32 of the section 112 forminy one container and a
bottom edge 30 of the section 112 forming the next succeeding
container. Each cut section 112 of the web is thereafter
-- 11 --
lf~8S
supplied to apparatus (not shown) which forms the section into
a tube and brings the marginal edge 10~ of each section into
engagement with each other to form and heat seal or weld the
seam 44. The resulting tubular construction is thereaEter
heat saaled or welded along seam 50 adjacent its bottom edge
30 by means (not shown) to complete an open container like
that shown in Fig. 1.
At this point, the container 2~ may be removed Erom
the system and packaged ~or supply to a processor for
subsequent filling and sealing the containers. Alternatively,
the system forming the container may fill it and seal it in
one operation. Thus, with the latter system, the container
20, after being formed into the construction shown in Fig. 1,
is filled with its contents 62 and vacuumized. The peel strip
means 54 is then closed and hermetically sealed, as described
heretofore, to isolate the contents 62 within the interior
from the ambient atmosphere. The top edge 32 is then folded
down or left upright, as desired.
It must be pointed out at this juncture that while in
the preferred embodiment of the invention shown in Fig. 1 here-
in the peelable closure 54 comprises a strip which is fixedly
secured to the inner surface of the container adjacent its
mouth by a pair of seals, this invention is not limited to
that construction. Hence, the closure strip can be secured in
place by any means. Moreover, the strip need not even be sep-
arate from the sheet material forming the container and can
thus be applied as a layer or coating strip on the inner sur-
face of the sheet material be~ore it is formed into the con-
tainer. Further still, the strip need not consist of two
plies or layers and thus may be in the form of a single ply or
- 12 -
layer or multi-plies or layers of the same or diEferent type
materials.
As should be appreciated Erom the foregoing, the
containers of the subject invention provide a viable
alternative to the use of rigid containers for the air-tight
storage of materials and without the disadvantages of prior
art flexible containers, namely, either the inability to be
readily reclosed due to structural damage to the container due
to the tearing of its walls or, if the container is cut open
at its seal, the reduction in storage capacity due to the
removal o~ the top of the container. The advantages of the
subject invention over the prior art are accomplished in a
simple and expeditious manner through the use of a peelable
closure at the mouth of the container which creates an
air-tight weakened seal that can be peeled open without
damaging the container itselE.
Moreover, the method(s) of the subject invention
provides a viable and commercially feasible means for readily
and inexpensively producing flexible containers having
air-tight peelable mouths with other seamed portions being
permanent seams.
Without further elaboration, the foregoing will so
fully illustrate my invention that others may, by applying
current or future knowledge, readily adapt the same for use
under various conditions of service.
- 13 -
