U.S. patent application number 14/898270 was filed with the patent office on 2016-05-19 for self-forming container.
The applicant listed for this patent is BEMIS COMPANY, INC.. Invention is credited to Mychal B. Brosch, Chris S. Mussell, Riley P. O'Shea, Michael D. Priscal.
Application Number | 20160137374 14/898270 |
Document ID | / |
Family ID | 52105034 |
Filed Date | 2016-05-19 |
United States Patent
Application |
20160137374 |
Kind Code |
A1 |
Brosch; Mychal B. ; et
al. |
May 19, 2016 |
SELF-FORMING CONTAINER
Abstract
A self-forming container having a continuous side wall with
opposing top and bottom edges connected by an interior side wall
surface, said side wall preferably having less than 10% shrink at
90.degree. C., and more preferably being nonshrinkable; and a heat
shrinkable connecting wall connected to at least first and second
opposing portions of the sidewall and forming therewith a adapted
for heat activated self-forming into a stand up con figuration
having a stable base connected to and supporting said side
wall.
Inventors: |
Brosch; Mychal B.; (Eden
Prairie, MN) ; Mussell; Chris S.; (New London,
WI) ; Priscal; Michael D.; (Neenah, WI) ;
O'Shea; Riley P.; (Grand Ledge, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BEMIS COMPANY, INC. |
Neenah |
WI |
US |
|
|
Family ID: |
52105034 |
Appl. No.: |
14/898270 |
Filed: |
June 20, 2013 |
PCT Filed: |
June 20, 2013 |
PCT NO: |
PCT/US13/46805 |
371 Date: |
December 14, 2015 |
Current U.S.
Class: |
383/104 |
Current CPC
Class: |
B65D 75/002 20130101;
B65D 33/007 20130101; B65D 33/08 20130101; B65D 75/008
20130101 |
International
Class: |
B65D 75/00 20060101
B65D075/00 |
Claims
1. A self-forming container comprising: a side wall having an
interior side wall surface; and a connecting base wall comprising a
heat shrinkable film; said connecting base wall connected to first
and second opposing portions of said interior side wall surface
thereby closing said side wall; whereby said container is adapted
for heat activated self-forming into a stand up configuration
having a stable base connected to and supporting said first and
second opposing portions of said interior side wall surface.
2. A self-forming container, as defined in claim 1, wherein said
heat shrinkable film has a machine direction shrink of at least 10%
at 90.degree. C.
3. A self-forming container, as defined in claim 1, wherein said
heat shrinkable film has a machine direction shrink force of at
least 50 g/mil at 90.degree. C.
4. A self-forming container, as defined in claim 1, wherein each of
said side walls has a machine direction modulus of elasticity of at
least 1000 MPa at 23.degree. C. and 50% relative humidity.
5. A self-forming container, as defined in claim 1, wherein said
heat shrinkable film has at least 40% shrink and less than 10%
shrink at 90.degree. C. in at least one direction.
6. A self-forming container, as defined in claim 1, wherein: said
side wall has top and bottom edge portions; and said connecting
base wall is connected to said side wall proximate said side wall
bottom edge portion.
7. A self-forming container, as defined in claim 1, wherein said
connecting base wall is attached to said side wall with a single
gusset.
8. A self-forming container, as defined in claim 1, wherein said
connecting base wall is attached to said side wall with a plurality
of gussets.
9. A self-forming container, as defined in claim 1, wherein said
connecting base wall has at least 10% greater shrink at 90.degree.
C. than said side wall in the same direction.
10. A self-forming container, as defined in claim 1, wherein said
heat shrinkable film has a machine direction shrink value of at
least 30% at 90.degree. C.
11. A self-forming container, as defined in claim 1, wherein said
side wall is semi-rigid, rigid, or tensiff.
12. A self-forming container, as defined in claim 1, wherein: said
side wall has less than 10% shrink at 90.degree. C.; and said
connecting base wall has at least 10% greater shrink at 90.degree.
C. in at least one direction than the side wall in that same
direction.
13. A self-forming container, as defined in claim 1, wherein: said
side wall is continuous having opposing top and bottom edges
connected by said interior side wall surface, said side wall having
less than 10% shrink at 90.degree. C.; and said connecting base
wall having at least 10% shrink at 90.degree. C. in at least one
direction.
14. A self-forming container, as defined in claim 1, wherein: said
side wall has a percentage shrink, at temperature T.degree. C., of
from 0 to "A" in at least one axial direction; and said connecting
base wall has a percentage shrink, at said temperature T.degree.
C., of 10+"B" in at least one direction; where "T" is from 80 to
150.degree. C., "A" is from 0 to 30, and "B".gtoreq."A".
15. A self-forming container, as defined in claim 14, wherein: "T"
is 90.degree. C.
16. A self-forming container, as defined in claim 14, wherein: "T"
is 120.degree. C.
17. A self-forming container comprising: a first side wall having a
perimeter with opposing top and bottom edges connected by opposing
first and second side edges; a second side wall opposite said first
side wall, said second side-wall having a perimeter with opposing
top and bottom edges connected by opposing first and second side
edges; and a bottom wall comprising a heat shrinkable film; wherein
said first side edges of said first and second sidewalls are
connected and said second side edges of said first and second
sidewalls are connected to form a continuous inner side wall
surface of said container and said bottom wall is connected to said
first and second walls proximate their respective side wall bottom
edges; and whereby said container is adapted for heat activated
self-forming into a stand up configuration having a stable base
connected to and supporting said first and second side walls.
18. A self-forming container, as defined in claim 17, wherein said
first and second side walls have less than 5% shrink at 90.degree.
C. in both machine and transverse directions.
19. A self-forming container, as defined in claim 17, wherein said
first and second side walls are semi-rigid, rigid, or tensiff.
20. A container forming band comprising: a shrink force strip
disposed between a first nonshrink strip and a second nonshrink
strip said first and second nonshrink strips and said shrink force
strip sealed together at first and second opposing ends.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present application relates generally to packaging and
more specifically to flexible synthetic polymeric packaging.
[0003] 2. Background Information
[0004] Articles such as food, healthcare, personal care, office,
home and garden supplies, etc. can be held within a container, e.g.
a pouch, for ease of transport and use, and to protect the contents
from microbial contamination or contact with air, moisture, dirt,
etc. The container is typically sealed to provide a barrier to
deleterious materials or energy.
[0005] Packaging having multilayer structures where one layer is a
heat shrinkable film and another layer is a non-shrinkable film
have been disclosed. However, there are few packages which combine
heat shrinkable films with non-shrinkable films. One example is
U.S. Pat. No. 7,964,255 (Fink et al) assigned to Micro Shaping,
Ltd. which discloses packaging using a combination of a first layer
of heat shrinkable material and a second layer of non-heat
shrinkable material with microwave susceptors arranged in a pattern
in-between to create areas of increased stiffness after
microwaving. Also, U.S. Pat. No. 5,302,402 (Dudenhoffer et al)
discloses packaging for bone-in cuts of meat where a biaxially,
heat shrinkable, thermoplastic film bag has a non-heat shrinkable,
relatively thick, patch adhered to the bag to provide resistance to
puncture and abrasion.
[0006] In addition, one package uses a differential in shrink force
to provide curl resistance when packaging foods such as ribs which
are prone to shape distortions. This curl resistant packaging is
made from a heat shrinkable laminate bag for bone-in meat products
and has been disclosed in U.S. Patent Application Publication No.
2006/0177612 (Peterka). Peterka's package combines a heat
shrinkable bag with opposing heat shrinkable laminates on either
side of the bag where one laminate has a higher total free shrink
value than the bag or the laminate of the opposing side of the
bag.
[0007] In the art, known containers include pouches with contents
held between two sheets that form the pouch. Also, one typical
package is termed a "stand up" pouch (SUP) which has the ability to
be upstanding on a stable base as long as the pouch is filled with
contents. SUPS are available in a great variety of structures.
[0008] One example of the type of stand up pouch package is
disclosed in U.S. Pat. No. 3,935,993 (Doyen et al.) which describes
a freestanding container having a pair of side walls with a pair of
end panels where the end panels each have a central fold using
gusset forming strips and curvilinear heat seal seams. Other stand
up containers are disclosed e.g. in U.S. Pat. Nos. 4,837,849;
6,722,106; 6,060,096; and EP No. 823,388. Disadvantageously, the
aforementioned packages rely upon their package contents to provide
support for a stand up configuration and, absent contents, may
easily collapse.
[0009] Attempts been made to produce self-expanding containers and
pouches. For example, mechanisms such as extensible stays (U.S.
Pat. Nos. 5,174,658; 5,184,896; expandable polymers (U.S. Patent
Publication No. 2004/0005,100); and hand distortable, reinforcement
elements (U.S. Patent Publication No. 2003/0002,755) have all been
proposed to create stable stand up pouches or packages.
[0010] These previous attempts are expensive and complicated to
manufacture. Also, there is a continuing need for provision of more
useful, efficient, and economical packaging having a stable, stand
up, voluminous configuration.
BRIEF SUMMARY
[0011] In one form of the present invention, a self-forming
container is provided having (a) a side wall with opposing top and
bottom edges connected by an interior side wall surface, and (b) a
connecting wall connected to at least first and second opposing
portions of the sidewall and forming therewith a container wherein
the connecting wall is heat shrinkable in at least one direction
and the side wall is less heat shrinkable, and preferably not heat
shrinkable, in that same direction. Thus, the container is adapted
for heat activated, self-forming into a stand up configuration
having a stable base connected to and supporting the side wall.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a self-formed container in
accordance with the present invention.
[0013] FIG. 2 is a top view of the self-formed container of FIG.
1.
[0014] FIG. 3 is a perspective view depicting the bottom of the
self-formed container of FIG. 1.
[0015] FIG. 4 is a bottom view of a self-formed container in
accordance with the present invention.
[0016] FIG. 5 is a front view of a self-forming container in
accordance with the present invention.
[0017] FIG. 6 is a slightly expanded cross-sectional view taken
along lines 6-6 of FIG. 5.
[0018] FIG. 7 is a side view of the container of FIG. 5.
[0019] FIG. 8 is a top view of the container of FIG. 5.
[0020] FIG. 9 is a bottom view of the container of FIG. 5.
[0021] FIG. 10 is a front view of an embodiment of the present
invention which has a double gusset.
[0022] FIG. 11 is a slightly expanded cross-section taken along
lines 11-11 of FIG. 10 showing a double gusset insertion.
[0023] FIG. 12 is a side view of the container FIG. 10.
[0024] FIG. 13 is a bottom view of the container of FIG. 10.
[0025] FIG. 14 is a top view of the container of FIG. 10.
[0026] FIG. 15 is a perspective view of the container of FIG. 10
after heat forming.
[0027] FIG. 16 is a top view of the inventive container of FIG.
15.
[0028] FIG. 17 is a bottom view of the inventive container of FIG.
15.
[0029] FIG. 18 is a partial view showing a portion of the heat
activated inventive container of FIG. 17 enlarged for magnification
purposes to show layer details.
[0030] FIG. 19 is a schematic front view of another embodiment of a
container in accordance with the invention.
[0031] FIG. 20 is a schematic side view of FIG. 19.
[0032] FIG. 21 is a schematic view of an alternative embodiment of
the inventive self-forming container.
[0033] FIG. 22 is a schematic plan view of an alternative
embodiment of the inventive self-forming container having a lap
sealed side panel.
[0034] FIG. 23 is a schematic view of an alternative embodiment of
the inventive self-forming container of FIG. 22 taken along lines
23-23.
[0035] FIG. 24 is a schematic view of an alternative embodiment of
the inventive self-forming container having resistance strips.
[0036] FIG. 25 is a schematic sectional view taken along lines
25-25 of FIG. 24 and slightly expanded for illustration.
[0037] FIG. 26 is a schematic front view of an inventive force
strip which may activate a self-forming aspect of the present
invention.
[0038] FIG. 27 is a schematic end view of the force strip of FIG.
26.
[0039] FIG. 28 is a schematic top view of the force strip of FIG.
26.
[0040] FIG. 29 is a schematic plan view of the force strip of FIG.
28 after activation by heat shrinking.
[0041] FIG. 30 is a schematic view of an alternative lap seal
embodiment of the inventive force strip after activation by heat
shrinking.
DETAILED DESCRIPTION
[0042] There are many prior art package designs which employ
plastic, polymeric, metallic, cellulosic or noncellulosic sheets,
films or foils having one or more layers made by well-known
processes including extrusion or coextrusion, as sheets or tubes,
wet laid or dry laid, forming, spunbonding, tubular blown or slot
cast, and which made be laminated, coating laminated, adhesive
laminated, etc. Such materials generally are formed with stable
dimensions over a wide range of conditions and temperatures. Where
shrinkage does occur it is viewed as a defect to be minimized and
avoided. These nonshrink materials form the bulk of flexible
packaging in commercial use today and are found in use for
packaging a range of goods from bread bags to cereal boxes, bacon
pouches, candy bags and stand up pouches for beverages, candy, and
prepared food mixes, etc.
[0043] There is also a line of specialty packaging that has been in
long use which intentionally builds heat shrinkability into
polymeric film structures whereby a package may be heat activated
at elevated temperatures to cause the entire packaging to shrink
its dimensions typically to conform to and/or compress the contents
of the package to provide a neat appearance, tamper resistance or
evidence, retain product integrity against water purge, fat out,
etc. These heat shrinkable films are often used to package meat
e.g. beef, lamb, and pork for shipping from slaughter houses to
supermarket butcher departments, and also for skin tight turkey or
poultry packaging, cheese packaging, frozen foods such as pizza, as
well as for packaging reams of paper, books, DVDs, boxes, and
irregularly shaped articles, multi-packs, etc.
[0044] In the present invention, novel use is made of these two
ideas by coupling a nonshrink packaging structure with a heat
shrinkable packaging structure in a specific manner to cause a
container to change shape and form a stable stand up container
which at normal ambient room temperatures resists return to its
pre-shrunk configuration which is typically a lay flat
configuration. Many uses and advantages are possible with the
inventive packaging. It may e.g. replace a less stable traditional
stand up flexible pouch which has no resistance to collapsing into
a lay flat configuration unless filled with contents. Thus, an
empty stand up pouch is inherently unstable which limits its
utility. Embodiments of the present invention may also be
advantageously used in place of rigid or semi-rigid containers e.g.
thermoformed tubs, bottles, metal and rigid plastic cans, and the
like. These containers are bulky to ship and store prior to filling
with contents. In contrast, the present invention may conveniently
be shipped and stored flat and expanded to a stable almost
semi-rigid or non-collapsible state when desired for either product
filling, display or use with easy access to the container contents
after opening. These and other advantages, and desirable properties
and combinations thereof will be readily apparent from the
description below.
[0045] As used herein the term "semi-rigid" means a material having
a modulus of elasticity in either flexure or tension of between 70
and 700 MPa at 23.degree. C. and 50% relative humidity according to
ASTM D747, D790, D638, or D882 (ASTM D883).
[0046] Rigid plastics have a modulus of elasticity in either
flexure or tension greater than 700 MPa at 23.degree. C. and 50%
relative humidity according to ASTM D747, D790, 13638, or D882
(ASTM D883). Preferred rigid plastics for certain embodiments will
have a modulus of elasticity greater than 1000 MPa, or
advantageously in certain embodiments, greater than 1.4 GPA.
Especially preferred for certain embodiments are side walls made
from rigid plastics sheets having a modulus greater than 1.4 GPa
and having a sheet thickness between 10 to 20 mils, and plastic
sheets having this combination of thickness (10-20 mil) and modulus
of elasticity (>1.4 GPa) are defined herein as "tense".
[0047] In one embodiment of the present invention, a self-forming
container is provided by making novel use of several thermoplastic
film properties including the ability of one type of film to heat
shrink and the ability of another type of film to resist heat
shrinkage. These two properties are arranged in the present
invention so as to cause a container to self-form at elevated
temperature into a stable formed configuration which resists return
to its former configuration while providing a stable roomy
compartment for product contents that resists collapsing upon
itself. Preferably, a shrink film is coupled with a nonshrink film,
but it will become apparent that two shrink films having a
differential in same direction shrink may also be used.
[0048] Thus, a self-forming container may be provided having a
continuous side wall with opposing top and bottom edges connected
by an interior side wall surface, with this side wall having less
than 10% shrink at 90.degree. C.; and a connecting wall connected
to at least first and second opposing portions of said sidewall and
forming therewith a container, the connecting wall having at least
10% shrink at 90.degree. C. in at least one direction; and whereby
the container is adapted for heat activated self-forming into a
stand up configuration having a stable base connected to and
supporting the side wall.
[0049] By the phrase a "continuous side wall" is meant a side wall
which forms a circuit, loop or continuous path from a starting
point to a point distal therefrom and back again. For example, a
continuous side wall may be provided by: (i) a seamless tube; (ii)
a single sheet connected to itself e.g. by a lap seal or fin seal
or other connecting means; (iii) a plurality of side wall segments
attached to one another to form a circuit or loop; or (iv) an
enclosed wall; and the side wall may be either foraminous or
nonforaminous, permeable or impermeable to various materials,
substances, solids, liquids, energies, etc.
[0050] In another embodiment a self-forming container is provided
comprising: a continuous side wall having opposing top and bottom
edges connected by an interior side wall surface, with the side
wall having a percentage shrink at a temperature "T" (e.g. between
80-150.degree. C., and preferably 90.degree. C.) of from 0 to "A"
in at least one axial direction; and further having a connecting
wall connected to at least first and second opposing portions of
the sidewall and forming therewith a container. The connecting wall
has a minimum percentage shrink at a specified temperature e.g.
between 80-150.degree. C., (such as at 90.degree. C. in certain
embodiments) of 10+"B" in at least one direction; where "A" is from
0 to 30, and "B".gtoreq."A". The container is adapted for heat
activated change or self-forming into a stand up configuration
having a stable base connected to and supporting the side wall.
[0051] Preferably, the sidewall will have less than 5% shrink in
both MD & TD, more preferably, less than 3%, most preferably
0%. The connecting wall will have at least 10% shrink in one
direction and suitably at least 15, 20, 25, 30, 35, 40, 45, 50% or
higher shrink in one direction, preferably the machine direction.
Preferably, the connecting wall will also have less than 15%, 10%,
5%, or most preferably less than 3% shrink in the other direction,
preferably transverse direction.
[0052] The temperature selected for the parameter in the above
paragraph may be selected with consideration of the materials
chosen for the package container materials and/or contents. For
example, polyolefins such as polyethylene in its various forms, and
polypropylene, as homopolymers and copolymers, melt (and also have
softening points and glass transition temperatures) over a range of
temperatures. These temperature ranges may differ from polymer to
polymer and from polymer family to polymer family e.g. the melting
points and/or melting point ranges of polyolefins may differ from
other polymers such as nylons or polyesters. Containers according
to the present invention may be made of materials for which retort
temperatures and pressures are required, or from materials more
suitable for other applications where lower temperature processing
is appropriate. In view of the present teaching and depending upon
the desired packaging application, suitable materials may be chosen
and orientation built into a heat shrinkable film for activation
under desired conditions including e.g. heat activation and heat
stability at appropriate respective temperatures or temperature
ranges. The temperature at which the free or unrestrained shrink
values or shrink forces may be determined may be 80, 85, 90, 95,
100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150.degree. C.
or even higher (or lower than 80) as dictated by the choice of
materials used and intended use of the container. For many
applications, it is contemplated that a temperature of 90, 120, or
130.degree. C. will be useful. Generally, with respect to the
choice of material for the heat shrinkable film component of the
container, a temperature will be selected which is near the
orientation temperature of the shrink imparting material, or blends
thereof, e.g. such temperatures are between (a) either the glass
transition temperature T.sub.g or the Vicat Softening Point
(V.sub.sp), and (b) the melting point (m.p.) of the predominant
polymer or polymer blend which controls the shrink values. Where
polymer blends are used in a shrink layer or layers which control
the shrink of the film and melting point is an important physical
characteristic of the layer, it may be determined and defined in
terms of "average melting point". For a given polymer blend this
may be calculated by adding the product of the individual polymer's
melting point and its blend fraction, i.e. polymer 1 melting point
times its blend fraction plus polymer 2 melting point times its
blend fraction plus the corresponding factor for any other
components in the blend. This is a guide, but may in any case be
determined empirically without undue experimentation.
[0053] In another embodiment, a self-forming container is provided
which has a first, preferably semi-rigid, rigid or tensiff, side
wall having a perimeter with opposing top and bottom edges
connected by opposing first and second side edges; and a second,
preferably semi-rigid, rigid, or tensiff, side wall opposite the
first side wall, the second side-wall having a perimeter with
opposing top and bottom edges connected by opposing first and
second side edges; and a bottom wall comprising a heat shrinkable
film. The first side edges of the first and second sidewalls are
connected to each other and the second side edges of the first and
second sidewalls are connected to each other to form a continuous
inner side wall surface of the container and the bottom wall is
connected to the first and second walls proximate their respective
side wall bottom edges. This container is also preferably adapted
for heat activated self-forming into a stand up configuration
having a stable base connected to and supporting said first and
second side walls.
[0054] In another embodiment of the invention, a self-forming
container has (a) a side wall having top and bottom edge portions,
and opposing first and second side portions; and (b) a bottom wall
comprising a heat shrinkable film. The side walls are flexible,
resiliently deformable, and/or semi-rigid, preferably a combination
thereof. The bottom wall is connected to the side wall about the
side wall bottom edge portion. The container may be subjected to
elevated temperature i.e. above ambient room temperature or
23.degree. C., and this temperature supplies heat which activates
the heat shrinkage properties changing the container from a lay
flat or flexible collapsible configuration into a stand up
configuration which resists collapsing at room temperature under
ambient conditions, which process is termed "self-forming" and
which container after heat activation and change is termed
"self-formed". This self-formed stand up configuration has a
relatively stable base connected to and supporting the side wall
which may comprise first and second side wall portions or
panels.
[0055] Suitable materials which may be selected and used for the
side wall include many of the same materials that may be used to
construct a typical container wall and may be monolayer or
multilayer in construction. Multilayer films may also include
micro-layer technology. These micro-layers including panel layers
may be utilized in either the non-shrink films or sheets, or the
heat shrinkable films and sheets utilized in constructing
containers, whether sidewall, or connecting wall, or shrink bands,
in accordance with the present invention. Examples of suitable
materials for containers of the present invention include
polyolefins, polyethylene terephthalates, polyamides, nylons,
polystyrenes, polyacrylates, and generally any polymer that is
known for use in flexible polymer packaging including foamed
polymers e.g. closed celled foamed sheets which may have heat (i.e.
hot or cold) or moisture insulation properties, or varying
appearance attributes. Such materials may be homopolymers,
copolymers, and their derivatives and blends thereof. Metal foils
and metalized films are also contemplated as are paper, paperboard,
nonwoven sheets of resilient deformation and metallized versions
thereof. One or more functional properties may be contributed by
one or more layers including desired levels of heat sealability,
optical properties e.g. transparency, gloss, haze, abrasion
resistance, coefficient of friction, tensile strength, modulus of
flexure or tension, Young's modulus, flex crack resistance,
puncture resistance, rigidity, stiffness, abrasion resistance,
printability, colorfastness, flexibility, stretch or shrinkability,
dimensional stability, barrier properties to gases such as oxygen,
or to moisture, light of broad or narrow spectrum including e.g. UV
resistance, etc.
[0056] Many of the same thermoplastic polymeric materials
identified for side wall construction may be used for constructing
the heat shrinkable connecting wall panels of the present invention
as long as the resins are selected for their ability to be stretch
orientated by tenter frame or double bubble or trapped bubble or
machine direction cast orientation (MDO) processes as further
described below. Typically employed resins for use in making the
heat shrinkable films of the prior art may also be used in the
present invention. Especially preferred are polyolefins, e.g.
ethylene polymers and copolymers, cyclic polyolefins, and styrenic
copolymers.
[0057] A particularly preferred blend may be made with a cyclic
olefin copolymer that is commercially available from Topas Advanced
Polymers GmbH under the trade name Topas 8007F-400 blended with 30
wt. % of a conventional ethylene octene-1 copolymer commercially
available from The Dow Chemical Company under the trade name Attane
NG 4701G (hereinafter COC:EAO blend). Another suitable material is
styrene butadiene block copolymer having a radial or star block
configuration with polybutadiene at the core and polystyrene at the
tips of the arms. Such polymers are commercially available from
Chevron Phillips Chemical Co. under the trade designation K-Resin.
These polymers reportedly contain about 27% butadiene or more in a
star-block form and often feature a bimodal molecular weight
distribution of polystyrene.
[0058] Heat shrinkable films of the present invention are axially
oriented with preferential orientation in the direction receiving
the most stretch during film formation. The resulting film shrinks
preferentially in that same direction that was stretched more
during film manufacture. Machine direction (MD) is along the
direction of film transport during or after extrusion. Transverse
direction (TD) is perpendicular to the direction of film transport.
Shrinkage is preferentially machine direction orientation (MD) if
more stretch is applied to the MD than to the TD, and TD if more
stretch is applied transverse than machine direction.
[0059] Films of the present invention have an MD or TD ratio (ratio
of oriented stretch length to the unstretched length in the MD or
TD direction, respectively). Advantageously, this ratio will be at
least 2:1, preferably at least 3:1, more preferably between about
3:1 to 5:1. Advantageously, uniaxially stretched films may be
employed, especially e.g. those films stretched in the machine
direction. There is no clear upper limit for the orientation ratio,
although films typically have a ratio of 10:1 or less.
[0060] The shrink films used in the present invention may have a
heat shrinkability (e.g. at 90.degree. C.) of at least 10%, 20%,
30%, 40%, 50%, 60%, 70% or higher in at least one direction. In
some preferred embodiments, the shrinkability is disproportionate
in one direction and advantageously a uniaxial shrink of 10, 15,
20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 percent or higher
may be used and may be couple with a cross-directional shrink value
that is less than 10% or preferably less than 5% or more preferably
less than 3% or even 0%, or may even slightly expand in the
cross-directional dimension e.g. up to 5% or preferably from 0 to
3%.
[0061] Preferred materials for use as container walls, panels,
pouch films, lidstock, force strips, side wall and connecting wall
layers, include nylons, polyesters, polystyrenic polymers, cyclic
olefin polymers, and polyolefin e.g. ethylene or propylene
homopolymers or copolymers, or mixtures thereof in any number of
layers, particularly, but not limited to, 1 to 9 to 14 layers or
more layers. Preferred polyolefins include ethylene homopolymers or
copolymers and may include low, medium, high and ultra-low or
ultra-high density polymers. Examples are high density polyethylene
(HDPE), ethylene alpha-olefin copolymers (EAO) preferably utilizing
butene-1, hexene-1, or octene-1 comonomer with a predominate
ethylene comonomer portion) and including e.g. linear low density
polyethylene (LLDPE), very low density polyethylene (VLDPE),
plastomers, elastomers, low density polyethylene (LDPE) copolymers
of ethylene and polar groups such as vinyl acetate or ethyl
acrylate e.g. ethylene vinyl acetate (EVA) or ethylene methyl
acrylate (EMA) or ethylene acrylic acid copolymer (EAA), functional
group modified polymers including e.g. anhydride modified EAOs.
Propylene homopolymers and copolymers including polypropylene and
propylene ethylene copolymer are useful. Container side wall
structures may also include a metal foil and may be a metal foil
laminate with metal foil and a polymeric layer such as nylon. It
may also be a metal foil laminate with an outer layer of
polyethylene terephthalate, a core layer of metal foil and an inner
layer of polyethylene. In this arrangement, the polyethylene
terephthalate layer serves as a protective layer to the foil, and
the polyethylene layer facilitates sealing. The foil is an
excellent barrier to foreign materials, organisms, oxygen, moisture
and light.
[0062] The present invention may utilize a gas barrier layer such
as aluminum foil, polyvinylidene chloride copolymers such as saran,
or ethylene vinyl alcohol copolymers (EVOH) which provide high
barriers to gas permeability or materials such as nylon which
impede gas permeation to a lesser extent than saran or EVOH.
[0063] Adhesives useful in the present invention include permanent
adhesives and pressure sensitive adhesives (PSA) commonly available
from many commercial sources. It is contemplated that acrylic and
anhydride modified polymers may be employed as well as many
adhesives which may be selected depending upon other material
selections for the side wall panels, connecting wall panels or
force strips.
[0064] Additives and processing aides; natural and synthetic
colorants, pigments and dyes; fillers such as calcium carbonate or
carbon black, antimicrobial agents may be incorporated into the
container walls, panels, and strips structures.
[0065] Suitable side wall structures may include stiff yet flexible
materials or semi-rigid or rigid, or tensiff panels having a
sealant layer up to 5 mils thick or greater. Multilayer composites
of e.g. a paper/polyolefin/metal foil/polyolefin structure may be
used.
[0066] The heat shrinkable connecting wall panels or force strips
may also be made of various materials. MD shrink is preferred. If a
force band is used, it may be sealed either inside or outside of
the container compartment(s).
[0067] Contemplated combinations of materials include:
(a) side wall--flexible, semi-rigid, rigid, or tensiff material
(preferably nonshrinkable) and connecting panel/strip--softer
material with an MD force strip or shrink band (b) side
wall--flexible, semi-rigid, rigid, or tensiff material (preferably
nonshrinkable) and connecting panel/strip--MD gusseted shrink
film
[0068] Minimum individual side wall and connecting wall panel
thicknesses of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19 mils are contemplated. Both minimum and maximum
thicknesses may be whatever is practical depending upon the nature
of the materials used which may be determined without undue
experimentation. It is expected that advantageously the sidewall or
connecting wall panel thicknesses may be less than 20, 19, 18, 17,
16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, or 4 mils. Also, in some
embodiments it is expected that a side wall of 3-7, 8-9 or 10-20
mils may be advantageously used. Generally stiff side walls are
preferred, especially tensiff materials. The side wall should
facilitate a bowing outward effect in cooperation with the forces
imparted by heat shrinking of the connecting wall panel or force
strip or band. The side wall may also advantageously include an
insulating material from heat, cold or moisture condensation such
as polymeric foam or cellulosic materials.
[0069] It should be apparent that other known package features may
be incorporated with the present package/container including
temperature indicators, easy opening features such as tear notches,
easy peeling structures, reclosable features such as peel-reseal
adhesives, zippers, slider-zippers, snaps, etc.
[0070] Referring now to the Drawings, FIGS. 1, 2, 3 and 4 represent
an embodiment of the invention and illustrate an open package
container which has been formed by heat activation into a stand up
configuration having a stable base. It will be appreciated that the
opening may be closed in certain embodiments, by various closures
or closure means such as mechanical or chemical fasteners, hook and
loop fasteners, heat seals, zippers, adhesives (either permanent or
temporary, peelable and/or resealable), etc. In FIG. 1, a
perspective view of a container 10 has a first panel 11 with an
first panel exterior surface 12 and an opposing first panel
interior surface 13 (See also FIG. 2). The first panel 11 is sealed
to a second panel 14 having a second panel exterior surface 15 and
second panel interior surface 16 by a perimeter seal 17 defining a
perimeter of a compartment 18 which is bounded by first panel 11,
second panel 14, and a heat shrunken connecting wall panel e.g. a
connecting base or bottom 19 (See FIGS. 2-4) of the container
10.
[0071] The first panel 11 has a top edge 20 and opposing bottom
edge 21 and a first side edge 22 and second side edge 23 and these
edges form a continuous perimeter 24 of the exterior and interior
surfaces of the first panel 11. The second panel 14, has a top edge
25 and opposing bottom edge 26 (See FIGS. 3 and 4), and a first
side edge 27 and second side edge 28 and these edges form a
continuous perimeter 29 of the exterior and interior surfaces of
the second panel 14.
[0072] The perimeter seal 17, is depicted as a continuous seal
having a first side seal segment 30 and second side seal segment 31
which are joined by front connecting seal segment 32 and a parallel
rear connecting segment 33 (See FIGS. 3 and 4), but it will be
appreciated that perimeter seal 17, or segments thereof, may also
be discontinuous, as for example, where a series of spot welds are
made to form the perimeter. Of course, a continuous seal is
generally preferred, but where the nature of the contents to be
held by the container admit, it may be desirable to have
discontinuities in sealing to allow ingress or egress of e.g.
moisture, air, etc. In the embodiment illustrated in FIG. 1, this
perimeter seal has a "U" shape, but it is further contemplated and
well within the scope of the invention to provide containers where
the side wall edges may be curved or at an angle, etc., and the
bottom edge may likewise be varied. A precept is for the inventive
container in its formed condition to have a stable base or
connecting wall that supports the container in an expanded
condition regardless of the presence or absence of contents within
the container. This expanded condition is typically non-collapsible
at room temperature. The illustrated embodiment in FIGS. 1-4 show a
container having a continuous side wall 34 about the interior and
exterior surfaces of the panels 11 and 14 due to perimeter first
and second seal segments 30, 31. However, a seamless tube may also
be provided to comprise this continuous side wall 34. Also as
previously noted, in the continuous side wall 34 there may be
discontinuities in the seal segments or alternatively the seal
itself may be continuous and hermetic. The aforementioned base or
connecting wall panel 19 extends across or generally transverse to
the side wall 34 to provide a support for maintaining the container
10 in an expanded condition as a consequence of heat activation of
the base/connecting wall 19.
[0073] The perimeter seal 17 may be either peelable or
non-peelable. In one embodiment, perimeter seal 17 is a peelable
seal which is peelable along at least a portion of the seal or
along the entire seal to provide access to the pouch contents.
[0074] Some embodiments of the present invention may be manually
opened without use of scissors or other tools, preferably using
easy to peel open systems such as peelable seals. "Peelable seal"
and like terminology is used herein to refer to a seal, and
especially heat seals, which are engineered to be readily peelable
without uncontrolled or random tearing or rupturing the packaging
materials which may result in premature destruction of the package
and/or inadvertent contamination or spillage of the contents of the
package. A peelable seal is one that can be manually peeled apart
to open the package at the seal without resort to a knife or other
implement to tear or rupture the package. Many varieties of
peelable seals are known in the art, such as those disclosed in
U.S. Pat. No. 4,944,409 (Busche et al.); U.S. Pat. No. 4,875,587
(Lulham et al.); U.S. Pat. No. 3,655,503 (Stanley et al.); U.S.
Pat. No. 4,058,632 (Evans et al.); U.S. Pat. No. 4,252,846
(Romesberg et al.); U.S. Pat. No. 4,615,926 (Hsu et al.) U.S. Pat.
No. 4,666,778 (Hwo); U.S. Pat. No. 4,784,885 (Carespodi); U.S. Pat.
No. 4,882,229 (Hwo); U.S. Pat. No. 6,476,137 (Longo); U.S. Pat. No.
5,997,968 (Dries, et al.); U.S. Pat. No. 4,189,519 (Ticknor); U.S.
Pat. No. 5,547,752 (Yanidis); U.S. Pat. No. 5,128,414 (Hwo); U.S.
Pat. No. 5,023,121 (Pockat, et al.); U.S. Pat. No. 4,937,139
(Genske, et al.); U.S. Pat. No. 4,916,190 (Hwo); and U.S. Pat. No.
4,550,141 (Hoh), the disclosures of which are incorporated herein
in their entirety by reference thereto.
[0075] A non-peelable seal may also be employed e.g. a strong
integral heat seal along either a portion or along the entire
perimeter. Permanent adhesives may also be used to form a
non-peelable seal. Non-peelable seals may be easily opened by
incorporating tear open features such as notches, and surface
weakened areas, or through the use of tools such as scissors,
etc.
[0076] The seals between (a) the a first side wall panel and a
second side wall panel, or (b) between any side wall panel and the
connecting wall can be formed by a variety of ways, but is
preferably a permanent seal. For example, the seal may be formed as
a weld heat seal by application of heat and pressure to the first
panel surface and the second panel surface (or a connecting wall
surface) with their respective surfaces in contact with each other
for a sufficient time to cause bonding, with cooling of the bonded
perimeter to form an integral permanent seal. Alternatively, an
adhesive can be sandwiched between the surfaces. Similarly, the
perimeter seal, may be a permanent seal made by use of a heat seal
or permanent adhesive. The perimeter seal, whether permanent or
peelable, in combination with the side wall and connecting panels
and in conjunction with an opening closure or extension of the
perimeter to act as a closure, can seal contents within the
compartment to keep out unwanted materials such as particles and
microbes.
[0077] Referring to FIG. 2, a top view of the self-formed container
10 of FIG. 1 is depicted having a first panel 11 having respective
exterior and interior surfaces 12, 13 and which is connected to a
second panel 14 having respective exterior and interior surfaces
15, 16 by perimeter seal 17. The perimeter seal 17 has first and
second side seal segments 30, 31 respectively, joined by front
connecting seal segment 32 (See FIG. 1) and a rear connecting seal
segment 33 (See FIGS. 3 and 4), and with panels 11 and 14 forms a
compartment 18. This compartment is defined by a continuous side
wall 34 formed by panels 11 and 14 which are joined by first side
seal segment 30 and opposing side seal segment 31. The side wall 34
has a continuous top edge 35 formed by top edges 20, 25 of the
first and second panels respectively, which are joined to each
other by the aforementioned heat seals 30, 31. First side heat seal
segment 30 is proximate to first and second panel first side edges
22, 23, respectively. Second side heat seal segment 31 is proximate
to first and second panel second side edges 23, and 28,
respectively. As previously noted, it is contemplated a seamless
tube could also be employed. Opposing top side wall edge 35 is a
bottom side wall edge 36 adjacent which a bottom connecting wall
panel 19 is attached to front connecting seal segment 33 and rear
connecting seal segment 33 to connect together the first and second
panels 11, 14 respectively, proximate bottom side wall edge 36,
which corresponds to their respective bottom edges 21, 26 (See
FIGS. 3 and 4). Compartment 18 has an opening 37 defined by the
side wall top edge 34, and also has an opposing closed base or
bottom connecting panel 19. This bottom connecting wall panel 19
has an interior surface 38, with a center fold line 39, separating
front and rear portions 40, 41 respectively of connecting panel 19.
This panel 19 is formed from a heat shrinkable film 42 which is
attached e.g. adhesively or preferably by heat sealing its
perimeter edge portions to the first and second panels 11, 14 by
the perimeter seal 17, as further described below. In contrast, the
side wall 34 is formed from materials having less heat shrink
properties than the bottom film 42 and is preferably not heat
shrinkable.
[0078] Referring now to FIG. 3, a perspective view depicting the
container bottom 43 of the self-formed container 10 of FIG. 1 with
attached side wall 34. The side wall 34 is formed from a first
panel 11 having exterior and opposing interior surfaces 12, 13, and
second panel 14 having exterior and opposing interior surfaces 15,
16, respectively. The first and second panels are preferably made
of nonshrinkable materials connected by an interposed connecting
wall panel such as bottom base panel 19 made of a heat shrinkable
film 42 which forms the container bottom or base 43. Connecting
panel 19 is preferably a heat shrinkable film 42 which prior to
heat activation of the container is folded about fold line 39 and
inserted between the first and second panels 11, 14 and sealed
thereto to form a integrally connected bottom 43. Panel 19 has a
first edge 44 (See FIG. 4) sealed to first panel 11 proximate first
panel bottom edge 21 at front connecting seal segment 32. Panel 19
has a second edge 45 (See FIG. 4) sealed to second panel 14
proximate second panel bottom edge 26 at rear connecting seal
segment 33.
[0079] Referring now to FIG. 4, a bottom view of a self-formed
container 10 of FIGS. 1-3 is depicted in accordance with the
present invention. In this view the thin wall thicknesses are
expanded for clarity of illustration. First panel 11 and second
panel 14 have interposed therebetween a connecting panel 19 having
a center fold line 39 separating a first bottom connecting panel
front portion 40 and a second rear portion 41. Panel 19 has a first
edge 44 sealed to first panel 11 proximate first panel bottom edge
21 at front connecting seal segment 32. Panel 19 has a second edge
45 sealed to second panel 14 proximate second panel bottom edge 26
at rear connecting seal segment 33. A first side edge 46 of panel
19 is folded back upon itself and this folded edge 46 is heated
sealed between the first and second panels 11, 14 at a lower
portion of the first side seal segment 30 of the perimeter seal 17
(See FIGS. 5-7). A second side edge 47 of panel 19 is likewise
folded back upon itself and this folded edge 47 is heated sealed
between the first and second panels 11, 14 at a lower portion of
the second side seal segment 31 of the perimeter seal 17 (See FIGS.
5-7).
[0080] Prior to heat activation the first, second and connecting
panels 11, 14, and 19 are all sealed together with the connecting
panel folded inwardly disposed sandwiched and sealed at the
periphery between the first and second panels, as best seen in
FIGS. 5-7. Upon heat activation, the heat shrinkable connecting
panel 19 shrinks, especially in the longitudinal direction along
the fold line 39 thereby pulling the first and second perimeter
seal segments towards one another. Since the first and second
panels are designed to have less shrink, and preferably no shrink,
in this longitudinal direction the first and second panel walls are
constrained to bow outward as the connecting panel 19 shrinks along
the longitudinal axis which corresponds to the fold line 39. This
contraction of the connecting base 19 and bowing of the first and
second panels creates an interior compartment 18 and self-forms the
structure into a container having a stand up configuration having a
stable base connected to and supporting the side wall i.e. the
first and second side wall portions. Since the connecting film 19
was folded inward and sealed to form a gusset, a relatively flat
bottom 43 is formed. The shrunken film 42 thickens as it shrinks
adding strength and rigidity and the forces and tensions between
the contracting bottom and noncontracting side wall creates an "I"
beam effect adding structural support that forms a stable container
regardless of the presence or absence of contents within the
container compartment.
[0081] Referring now to FIG. 5, a front view of a self-forming
container 10, of the type shown in FIGS. 1-4, prior to heat
activation is shown. A first panel 11 having an exterior surface
12, a top edge 20, opposing bottom edge 21, a first side edge 22
and opposing second side edge 23, overlays a similar second panel
(See FIGS. 6-7) and is sealed thereto by a perimeter seal 17 having
a first side seal segment and opposing second side seal segment
joined by a front connecting seal segment 32 and a rear connecting
seal segment (See FIGS. 3, 6 and 7). A bottom panel 19 (See FIG. 6)
is folded at fold line 39 and sealed between the first and second
panels 11, 14 at respective front and rear connecting seal segments
32 and 33 (See FIGS. 3 and 6) and at a lower portion 48 of the
first side seal segment 30 as well as at a lower portion 49 of the
second side seal segment 31. Preferably, the bottom panel is a
connecting wall which is heat sealable on one side and not heat
sealable on the other side under the chosen heat sealing conditions
such as temperature, pressure and dwell time. These conditions will
vary depending upon the choice of materials used. The bottom panel
may be a multilayer construction where the surface layer in contact
with the side wall is selected for enhanced sealing and the surface
layer of the bottom panel that is folded upon itself is selected to
resist bonding during a sealing operation.
[0082] The inventive self-forming container 10 may be shipped flat
without taking up much space, yet upon heat activation quickly
self-forms into a stand up configuration having a stable base which
may be set on a flat surface for filling and after filling may be
sealed and easily shipped and displayed on shelving without tipping
making an efficient use of space. Advantageously, product may be
sealed within the container prior to heat activation. Prior to or
after shipping, transport, purchase and at the point of use, a
stand up container may be formed by heat activation for convenience
of access to the container contents as the self-formed container
maintains a stable shape which may be designed to be for example
like a cup or bowl.
[0083] Typical contents for various embodiments of the inventive
container may include, for example, food including dry or liquid
foodstuffs such as soups, powdered drinks, cocoa, nuts, snack
foods, cereals, candy, dips, foodstuffs typically held in
semi-rigid or rigid containers and cans, pet food or supplies, home
and garden products, medical devices and products, as well as large
bag items for which prior art SUPs offer inadequate support e.g.
for flour, feed, cement, sand, fertilizer, etc.
[0084] Referring now to FIG. 6, an expanded cross-section taken
along lines 6-6 of FIG. 5 is depicted. In this view the interior
compartment 18 is slightly opened from its normal lay flat
configuration for purposes of illustrating the construction of the
container 10. First panel 11 having an exterior surface 12 and
interior surface 13, top edge 20 and bottom edge 21 is positioned
parallel to a second panel 14 having an exterior surface 15 and
interior surface 16, top edge 25 and bottom edge 26. Disposed
within these two panels 11, 14 is a heat shrinkable connecting wall
19 folded at 39 and having a first edge 44 and second edge 45 with
adjacent heat seal segments 32, 33 respectively.
[0085] Referring now to FIG. 7, a side view of the container 10 of
FIG. 5 is shown with first and second panels 11, 14 sealed together
at perimeter seal 17. First side seal segment 30 is shown having a
lower portion 48 which seals together folded connecting panel edge
46 sealed within and to panels 11 and 14. The first and second
edges 44, 45 of the connecting panel are adjacent to and sealed
proximate with first and second panel bottom edges 21, 26. Thus a
gusseted heat shrinkable bottom connecting wall is provided which
is adapted for heat activated self-forming into a stand up
configuration having a stable base connected to and supporting said
side wall.
[0086] Referring now to FIG. 8 a top view of the container of FIGS.
5-7 is shown with the top edge 20 of the first panel 11 and the top
edge 25 of the second panel 14. Panels 11, 14 are sealed together
proximate the first side edges 22, 27 of the first and second
panels 11, 14, respectively to form a first side seal segment 30.
Panels 11, 14 are also sealed together at the opposing end of the
container proximate the second side edges 23, 28 of the first and
second panels 11, 14, respectively to form a second side seal
segment 31. Between points "A" and "B" panels 11, 14 are unsealed
from panel top edges 20, 25 to the bottom connecting panel 19 (See
FIG. 6) to permit access to an interior compartment 18 (See also
FIG. 6).
[0087] Referring to FIG. 9, a bottom view of the container 10 of
FIGS. 5-8 is shown. First and second panels 11, 14 are sealed to
the connecting panel 19 along parallel front and rear connecting
seal segments 32, 33. First and second panels 11, 14 also sealed at
first and second side seal segments 30, 31 where these seals extend
through both the folds of the connecting panel 19 as well as both
panels 11, 14. Between points "A" and "B" the first and second
edges of connecting panel 19 are not heat sealed, but merely folded
along center fold line 39.
[0088] Referring now to FIGS. 9-17, an alternative embodiment of
the present invention is shown which depicts a container 50 which
is identical to the embodiment of container 10 shown in FIGS. 1-9
except that a double gusseted connecting wall panel 50 replaces the
single gusseted panel 19. Thus, FIG. 10 is a front view of
container 50 having a front panel 52 with perimeter seal 53 with a
dashed line showing a fold line limit 54 of a double gusseted
connecting wall 51. FIG. 11 shows an expanded cross-section taken
along lines 11-11 of FIG. 10 showing a double gusseted connecting
wall panel 51 inserted between front panel 52 and a rear panel 55.
Connecting wall panel 51 has first gusset fold 56 and a second
gusset fold 57 connected at mating fold 58. Panel 51 has a first
edge 59 sealed to front panel bottom edge portion 60 at front
bottom seal segment 61 and a second edge 62 of connecting panel 51
sealed to rear panel edge portion 63 at rear bottom seal segment
64. The panels 51, 52, 53, and perimeter seal 53 cooperate to form
an interior container compartment 65.
[0089] Referring now to FIG. 12, a side view of the container 50 is
shown having front panel 52 and rear panel 55 connected by a first
side seal segment 66 which secures an first side edge of folded
double gusseted connecting wall panel 51 between the panels 52 and
55.
[0090] Referring to FIG. 13, a bottom view of the container 50 is
depicted with front panel 52 and rear panel 55 sealed together
through a double fold of the connecting panel 51 at a first side
seal segment 66 proximate to edge 67 of panel 51 (See FIG. 11) and
at an opposing second side seal segment 68. The first and second
side seal segments are connected by front and rear bottom
connecting wall panel seal segments 61, 64 where a bottom edge
portion 60 of the front panel 52 is heat sealed to a first edge 59
of the connecting panel 51, and a bottom edge portion of 63 of the
rear panel 55 is heat sealed to a second edge 62 of the connecting
panel 51. A dashed line 58 depicts a mating fold axis which
connects first and second gussets56, 57 of the connecting panel 51
(See FIG. 11). As previously described the bottom connecting wall
panel may be designed to be heat sealable on the sidewall contact
side while being resistant to heat sealing on the opposite side so
that the gusset folds do not seal together in a manner which
prevents their unfolding. This may be easily done by providing a
multilayer bottom panel selecting seal side and opposing materials
in these respective layers which are suitable to achieve the
desired effect at the contemplated sealing temperatures and
conditions.
[0091] Referring now to FIG. 14 a top view is depicted of the
container 50 and shows front panel 52 and rear panel 55.
[0092] To activate self-forming, heat is applied to the inventive
container 50 by e.g. application of elevated temperatures above
room temperatures e.g. at 90.degree. C. by contacting the heat
shrinkable connecting panel with hot air or hot water thereby
causing it to shrink contract which results in self-forming into a
stand up configuration having a stable base connected to and
supporting said side wall.
[0093] Referring now to FIGS. 15-18 a heat activated container of
the type shown in FIGS. 10-14 having a double gusseted connecting
panel in an expanded configuration is depicted. In FIG. 15 a
perspective view of the expanded heat activated container
illustrates a wide mouth opening defined by a continuous side wall
top edge 69 where the upstanding side wall 70 is formed from a
front panel 52 which has an exterior surface 71 and opposing
interior surface 72 (See FIG. 16), and a rear panel 55 which has an
exterior surface 73 (See FIG. 16) and opposing interior surface 74,
where the front and rear panels 52, 55 are connected together to
form continuous side wall 70 e.g. by a first side seal segment 75
and opposing second side seal segment 76. These first and second
side seal segments 75, 76 are connected to each other by a front
bottom seal segment 61 and rear bottom seal segment 64 (See FIG.
17). Although the side wall 70 is shown being formed from two
panels 52, 55, it may be formed of a single panel sealed to itself
or from a seamless tube or from a plurality of side wall
elements.
[0094] Referring to FIG. 16, a top view of the expanded container
of FIG. 15 is shown and a number of the features and elements
described above are denoted. The compartment 65 is rendered
especially large by use of a double gusseted construction which
produces a flatter, more rectangular, compact and stable base in
the form of shrunken connecting wall panel 51 which has a first
front portion 78 and second rear portion 79 separated by a mating
fold axis 58. The heat activated shrunken connecting panel 51 (See
FIGS. 16 and 17) forces the side wall 70 to bow out at portions M
and N as a consequence of forcing the side wall portions in the
area of the first and second side seal segments 75, 76 respectively
to move towards each other being pulled by the shrink forces
applied through the heat activation of the heat shrinkable film
which forms the connecting wall panel 51. As the side wall portions
M, N bow out the area of the opening defined by side wall top edge
69 increases and a spacious interior compartment 65 is created
which is held open by the a stable base formed form the connecting
wall panel contraction which is now stable at room temperature and
at the ambient conditions of normal use by consumers or other end
users. It is further noted that it is contemplated that a lap
sealed side wall or seamless tubular side wall may be used with a
biaxial shrinkable connecting panel to produce an expanded
cylindrically shaped container and a generally circular connecting
wall panel. Also, the inventive container may be filled and sealed
through the open top or may be equipped with a second connecting
wall panel for a top closure which may be made of either a
shrinkable or nonshrinkable film to produce a regular box or can
type appearance. It may be advantageous in certain embodiments to
fill the internal compartment through the side wall or through a
seam or port in the side wall as well as through the top or bottom
or a special fitment applied to the container.
[0095] Referring now to FIG. 17 a bottom view of the container of
FIGS. 15-17 is shown having a double gusseted connecting panel 51
in an expanded configuration. As previously noted, use of a double
fold insertion of the connecting wall panel 51 is particularly
advantageous to produce a flatter base and maximize the volume of
the interior compartment 65 (See FIG. 16). As seen in FIG. 17 the
bottom wall panel 51 has in this particular embodiment an almost
square shape, but a variety of shapes are possible. In a preferred
embodiment an bottom panel 51 is made from a heat shrinkable film
having the property of shrinking greatly in (and having shrink
forces applied in) a uniaxial or longitudinal or machine direction,
but it is contemplated that such shrink properties may also be
employed in a transverse direction or in multi-axial e.g. biaxial
directions. Such shrink films are well known in the art of making
heat shrinkable, axially oriented films and may be made by a
variety of methods including MDO, tenter frames, double bubble or
trapped bubble stretch orientation processes such as those
described in U.S. Pat. Nos. 3,022,543; 3,456,044; 4,277,594;
5,076,977; and as described in "Films, Orientation" Encyclopedia of
Polymer Science and Technology, 3.sup.rd Ed., pp. 559-577, (2003,
John Wiley & Sons, Hoboken, N.J., USA) which is hereby
incorporated by reference in its entirety. Commercially available
heat shrinkable films are manufactured by many companies including
Curwood, Inc. of Oshkosh, Wis., USA and Bemis Flexible Europe of
Valkeakoski, Finland. Referring again to FIG. 17, bottom connecting
wall panel 51 is sealed e.g. by heat seals, to the side wall 70
forming a front bottom seal segment 61 and rear bottom seal segment
64 and a first side seal segment75 and opposing second side seal
segment 76. Seals 61, 64, 75, 76 form perimeter seal 53 which
constrains the connecting panel 51. Before sealing, a double fold
is made in the bottom connecting wall panel during insertion of the
heat shrinkable panel into the side wall interior (this is also
prior to heat activation which does not occur until after the
container is fully constructed). A first fold inward was made at
point E which continued to point F in the front portion of the
connecting panel 51 and a second fold inward was made at point G
which continued to point H in the rear portion of the connecting
panel 51. Mating fold axis line 58 represents a center line where
the centrally located portions of panel 51 return outwardly from
respective folds EF and GH meeting at the mating fold axis 58. It
should be noted that the perimeter seal 53 greatly constrains
movement in the direction along fold lines EF and GH, but that the
constraint transversely from the mating fold axis line 58 towards
portions M and N is much less forceful due to the presence of the
folds. After heat activation and shrinking of panel 51, Points E
and F are forceably drawn towards each other, as are points G and
H, and simultaneously, the film along the fold lines EF and GH is
pulled transversely outward towards M and N respectively as panels
52 and 55 bow outward.
[0096] Referring now to FIG. 18 a partial view showing a portion of
the heat activated inventive container of FIG. 17 is enlarged for
magnification purposes to show layer details where the folds of
panel 51 are sealed at the side seal. The following explanation
applied to both side seal areas where the panel 51 folds are sealed
into the sides. A second side seal segment 76 is shown with the
various layers that come into the seal area. The outer layers are
front panel 52 and opposing rear panel 55 and disposed therebetween
is the connecting panel 51 which has a first edge 59 and opposing
second edge 62 with a first inward fold 56 and opposing second
inward fold 57 connected by mating fold axis line 58. At the second
seal segment sufficient heat, pressure and dwell time are applied
to fuse, weld or otherwise chemically and/or physically bond
together the layers and folds to provide a strong anchor which is
preferably hermetic in nature at segment 76. As one follows the
layers toward the interior of the package structure the front panel
52 and first edge 59 of the connecting panel 51 are bonded along
their interface and this seal extends from the second side seal
segment 76 into the front bottom seal segment 61. Similarly, the
rear panel 55 and second edge 62 of the connecting panel 51 are
bonded along their interface and this seal extends from the second
side seal segment 76 into the rear bottom seal segment 64. However,
as one leaves the second side seal segment 76 along folds 56, 57
and mating fold axis line 58, these folds are not sealed or
otherwise bonded together and upon heat activation of the shrink
properties of the heat shrinkable film they easily unfold to
facilitate movement of the panel film toward s bowed portions M and
N (See FIGS. 16 and 17). While these folds facilitate movement
transversely, in the longitudinal or machine direction movement is
not subject to an unfolding effect and shrinkage in the
longitudinal/machine direction produces a direct force which
results in the bowing out of the side walls which are not shrinking
at the same rate or to the same extent (the side walls preferably
have no shrink in the longitudinal/machine direction).
[0097] Referring now to FIGS. 19 and 20, another embodiment of the
invention is shown where a self-formed container 80 having front
and rear nonshrink panels 81, 82 are sealed together by perimeter
seal 83 which also connects a heat shrinkable film that is shrunken
to produce a stable stand up container 80 attached to front panel
80 is a fitment 84 which has been attached e.g. by ultrasonic
welding a fitment flange 85 to an interior surface of the front
panel 81. The fitment 80 provides a pour spout and/or filling port
and may be equipped with a closure cap. It is contemplated that
this and various styles of fitments may be added to the top, side
or any surface or combination of surfaces of the container to add
utility of access to the container contents or interior
compartment.
[0098] Another embodiment of the present invention provides handle
means e.g. as shown in FIG. 21. It is contemplated that a pouch may
be made as described above with respect the single or
multi-gusseted pouches but having an extension forming a gripping
aid and/or peg board slot. For example, a pouch 86 may be provided
having a handle 87 formed therein whereby a pouch may be sold
containing cocoa or other powdered drink mixes or soups which may
be reconstituted by addition of water e.g. hot water which also
activates the self-forming aspect of the invention whereby the
connecting wall shrinks producing a stable stand up configuration
so that a stand up cup is formed which may be placed upon a flat
surface and the hot drink held by the handle for sipping and
consumption through a wide cup mouth 88. Such a self-forming
container could have a tear off top using scoring or other means
known in the art and be shipped relatively flat for efficient use
of space and lower shipping costs yet be self-formed into a useful
container for consumption of its contents by merely tearing off the
top, adding hot water and waiting a few seconds while the
transformation into a stable cup takes place. The shrinkage process
takes only a matter of seconds to complete, yet may be controlled
so that it is not so rapid as to cause unwanted ejection of the
contents. Conveniently, the handle may also be employed to hang
multiple units of the package for sale or display e.g. on a hook in
a peg board display.
[0099] Another embodiment of the invention is shown in FIGS. 22-23
where a self-forming container 89 is made from a nonshrinkable side
wall 90 having a front panel 91 with a first exterior surface 92
and a second interior surface 93 (See FIG. 23), and a back panel 94
having a first exterior surface 95 and opposing second interior
surface 96 with first and second wrap around side portions 97, 98,
respectively, lap sealed to the front panel. The lap seals weld
together the front panel to the second wrap around side portions
91, 94 of the back panel 94 at an interface between the front
panel's first exterior surface 92 and the back panel's second
interior surface 96. The interface between the second interior
surface of the front panel and the second interior surface of the
back panel 94 is unsealed thereby allowing expansion on the
interior compartment 99 into a circular shape. This may employ a
multilayer front panel having an easily sealed surface layer for
contact with the wrapped portions 91, 94 and a seal resistance
opposing surface to prevent sealing to the back panel's interior
surface 96. A heat shrinkable bottom connecting wall panel is
provided as described above for the preceding embodiments. By use
of lap seals a rounder more cylindrical container shape is
possible.
[0100] Another embodiment of the invention is shown in FIGS. 24-25
where a self-forming container 101 is made from a combination of a
side wall 102, a plurality of force strips 103, 104, 105, 106, and
first and second connecting panels 107, 108. This embodiment
illustrates a principle of the invention which is to couple a
shrink force with an opposing resistance to bring about a
deformation or bowing of a container side wall. Thus in the
illustrated container 101 the shrink force may be supplied by
either or both connecting walls 107, 108 and the resisting force
may be supplied by paired force strips 104, 106 and 103, 105 where
the force strips are nonshrink and are constrained to bow outward
under the influence of a shrink forces which are applied
longitudinally in the direction of the strips length.
Alternatively, the force strips may be shrinkable in their
longitudinal direction and the side wall 102 nonshrinkable and may
be semi-rigid, rigid or tensiff which can also cause the side wall
to bow outward forming a stable container.
[0101] Yet another embodiment of the invention is illustrated in
FIGS. 26-30 where a container forming band 109 is illustrated
having a central shrinkable film strip 110 sealed between two
nonshrinkable strips111, 112. The three strips 110, 111, 112 are
sealed together at first end seal area 113 and opposing second end
seal area 114 and the strips are not sealed to one another
therebetween. FIG. 26 shows a front view of the band 109 having a
first nonshrinkable strip 111. FIG. 27 is an end view of the band
109 with heat shrinkable strip 110 disposed between nonshrinkable
strips 111 and 112. FIG. 28 is a top view of band 109 with heat
shrinkable strip 110 disposed between nonshrinkable strips 111 and
112 prior to heat activation shrinking. In FIG. 29 the band 109 has
been subjected to heat e.g. 90.degree. C. for about 60 seconds
thereby causing the shrink strip 110 of band 109 to contract along
its length. Since the nonshrink bands 111 and 112 cannot contract,
internal forces cause them to bow outwards away from the
contracting force of the shrink strip 110. This shrink band 109 may
be attached to a nonshrink sidewall to produce a container which is
self-formable upon heat activation into a self-formed container
having a stable base with a stand up configuration. Also, the band
may be located on the exterior or interior of a container. For
example, it could be utilized in the interior with a central wall
structure between side wall structures to form a multi-compartment
package. Also, in another alternative embodiment, the nonshrink
strips may be replaced by nonshrink panels or a single nonshrink
panel which is seamless or sealed to itself to produce a container.
These embodiments will lay flat prior to heat shrinking yet
self-form into a stand up configuration having a stable base
connected to and supporting a continuous side wall when heat
activation causes the heat shrinkable strip to contract. Once
formed, the self-formed container resists collapsing into a lay
flat state at room temperature and typical ambient conditions e.g.
of pressure, radiation, etc.
[0102] Another variation on the shrink band embodiment described
above is shown in FIG. 30 which is similar to FIGS. 26-29 except
that the second nonshrink strip is longer and wraps around to the
first nonshrink strip where it is sealed with a lap seal. This
embodiment permits the shrink force strip to be sealed to either
the first and not the second nonshrink strip or vice versa to prove
a container surface which is rounder in appearance which may be
desirable for presentation. Thus, a container forming band 115 is
provided having a shrink force strip 116 disposed between a first
nonshrink strip 117 and a second nonshrink strip 118 and strips
117, 118 are sealed together at first and second end lap seals119,
120, respectively and the heat shrink force strip 115 is likewise
sealed to in this instance e.g. the first nonshrink panel 117
thereby producing a more pleasing surface 121 for advertising or
conveyance of information. The amount of shrink and/or shrink force
and opposing sidewall modulus may be adjusted to modify the extent
of warping or curvature of the sidewall e.g. from the slight bends
depicted in FIG. 20 to a can-like regular cylindrical shape.
[0103] Furthermore, the inventive container in various embodiments
described throughout this disclosure including e.g. a pouch, may
have inner surfaces of the sidewall e.g. respective first and
second panels as shown in various FIGS., and/or the connecting or
bottom panel wall may each comprise a layer that has a low
interaction with the pouch's intended contents, e.g. citrus
flavored drinks or medicines, or aromatic or flavanoid containing
products, and may be substantially chemically inert and/or resist
scalping of contents.
[0104] The side wall may have one or more layers e.g. a first panel
and a second panel, and can be made from the same materials or
different materials. Furthermore, the side wall and its panels can
be a multilayered or laminated structure. The structure may be a
single layer or a plurality of layers which may be polymeric,
metallic, sheets, films or foils or combinations thereof. For
example, the first and second panels can have a metal foil layer
that forms an intermediate or core layer inside of either or both
of the first and second panels and one or more polymer layers that
form the inside and/or outside surface of the pouch 30. The metal
foil layer can be aluminum. The one or more polymer layers can
include cellulosic or preferably noncellulosic polymers,
homopolymers or copolymers, blends of polymers. The panels may be
constructed of one or more materials which contribute specific
functionality to the package. Examples of suitable materials for
one or more of these layers include polymers or copolymers such as
polyethylene terephthalate, polyolefins e.g. polyethylene,
polyester, nylon, styrenic polymers, cyclic polyolefins, metal
foils, metalized films, oxygen or moisture barrier polymers such as
ethylene vinyl alcohol copolymers, polyacrylonitriles, and
vinylidene chloride copolymers such as saran. For example, a
polyethylene layer can be sandwiched between a polyethylene
terephthalate layer and the foil layer. The pouch can further have
a sealant layer that forms the inside surface of the container's
compartment such that an oxygen and/or moisture and/or UV light
barrier layer such as the metal foil layer can be sandwiched
between the sealant layer and the one or more polymer layers. The
sealant layer can include polyethylene, ionomer, polyacrylonitrile,
polyester, Barex.RTM., or Surlyn.RTM.. The laminate may include
more layers than those described above such as an adhesive layer
between the sealant layer and the foil layer to adhere the sealant
layer to the foil layer. Advantageously, sealants such as adhesives
may be pattern applied. The thickness of the multilayer structure
laminate may be any suitable thickness that provides structural
integrity, and desired combinations of properties which may vary
depending upon the nature of the contents, usage requirements and
which may include e.g. consideration of barrier properties, abuse
resistance, heat resistance, heat sealability, scalping resistance,
puncture resistance, abrasion resistance, optical properties, haze,
gloss, printability, transparency, as may be determined by those
skilled in the art in view of the present disclosure. It is
expected that typical preferred thicknesses, for example, may be
advantageously employed between about 50 .mu.m and about 500
.mu.m.
[0105] In one contemplated method of manufacture, three rolls of
pouch film web are placed on a machine and brought together to form
heat sealed pouches. A second nonshrinkable pouch film is applied
and heat sealed to a first nonshrinkable pouch film with a third
heat shrinkable connecting panel film plowed in between the first
and second pouch films and sealed thereto. The sealed films are
severed from the three webs to provide an individual pouch with the
heat shrinkable connecting film gusseted and located between the
two side wall panel films and with the pouch having one open end
available for product insertion. The three side sealed pouch is
used to package an article by a manufacturer or packager who places
a product in the pouch either before or after self-forming, and
completes the final seal. The sealed package is then shipped for
distribution or resell in either an un-self-formed, non-expanded
state or in a self-formed, expanded container configuration.
[0106] Unless otherwise noted, the following physical properties
are used to describe the present invention, films and polymers have
reported values in accordance with, or properties which are
measured by, either the test procedures described below or tests
similar to the following methods unless otherwise noted.
[0107] Density: ASTM D-792
[0108] Average Gauge: ASTM D-2103
[0109] Tensile Strength: ASTM D-882, method A
[0110] Percent Elongation: ASTM D-882, method A
[0111] Melt Index: ASTM D-1238, Condition E(190.degree. C.)
[0112] Melting Point: ASTM D-3418, DSC with 5.degree. C./min.
heating rate.
[0113] Vicat Softening Point: ASTM D-1525-82
[0114] Oxygen Gas Transmission Rate (O.sub.2GTR): ASTM
D-3985-81
[0115] Water Vapor Transmission Rate (WVTR): ASTM F 1249-90
[0116] All ASTM test methods noted herein are incorporated by
reference into this disclosure.
[0117] Shrinkage Values: Shrinkage values are defined to be values
obtained by measuring unrestrained (or "free") shrink of a 10 cm
square sample immersed in water at 90.degree. C. (or the indicated
temperature if different) for five seconds. Four test specimens are
cut from a given sample of the film to be tested. The specimens are
cut into squares of 10 cm length in the machine direction by 10 cm
length in the transverse direction. Each specimen is completely
immersed for 5 seconds in a 90.degree. C. (or the indicated
temperature if different) water bath. The specimen is then removed
from the bath and the distance between the ends of the shrunken
specimen is measured for both the machine (MD) and transverse (TD)
directions. The difference in the measured distance for the
shrunken specimen and the original 10 cm side is multiplied by ten
to obtain the percent of shrinkage for the specimen in each
direction. The shrinkage of four specimens is averaged for the MD
shrinkage value of the given film sample, and the shrinkage for the
four specimens is averaged for the TD shrinkage value. As used
herein the term "heat shrinkable film at 90.degree. C." means a
film having an unrestrained shrinkage value of at least 10% in at
least one direction.
[0118] As used herein, the term "shrink force" may refer to the
force or stress exerted by the film on the package as the film
contracts under heat. A value representative of the shrink force
may be obtained using an Instron Tensile tester with a heated
chamber.
[0119] Shrink Force: The shrink force of a film is equal to that
force or stress required to prevent shrinkage of the film under
specified conditions. Shrink force values are measured using the
Instron heated chamber. The position was held constant and the
temperature was ramped up. The Instron software was used to collect
force vs time data. The temperature/time was manually recorded
throughout each run and time data converted to temperature. Six
replicates using the following Run Conditions:
1'' wide strips; 4'' jaw span held constant throughout test caliper
measured and entered into program sample loaded with minimal force
at 25.degree. C. Temperature controller was set to 400.degree. C.
to ramp the temperature up quickly. Test time/speed was set to 5
minutes at 0 mm/min. Instron software recorded Force vs Time
Manually recorded Force, Time and Temp in 5.degree. C. increments
Test was started and temperature ramped up as soon as door was
closed. Data collection speed was 100 ms per data point.
[0120] The shrink force for the film sample is reported in Newtons.
The shrink force may be determined by cutting out rectangular
specimens from sample films with the long axis parallel to either
the machine or the transverse direction. The specimens are clamped
at the short ends so that the force to be measured is applied along
the long axis. One clamp is stationary, while the other clamps are
housed in a small oven whose heating rate can be accurately
controlled. The specimen is heated and the force needed to hold the
moveable clamp at a fixed distance from the stationary clamp is
measured. This force is equal to and opposite the shrink force.
[0121] Plastic films and layers employed in the present invention
may be manufactured by various processes e.g. cast films using e.g.
a slot die, or conventional blown films where a tubular film is
produced directly from the die melt. Also, molded, thermoformed,
blow molded sheets, semi-rigid solid, hollow or foamed bodies may
also be produced. In a preferred embodiment, extrusion is by cast
extrusion. In a preferred process for making an oriented, heat
shrinkable film, a polymeric resin is melt extruded through a slot
die onto a chilled roller where a cooled sheet having a temperature
below the melting point of the polymer(s) is produced, and then
preferably oriented by reheating to the polymer's orientation
(draw) temperature range while stretching in the machine direction
(e.g. by using known processes such as take off rollers travelling
at a higher rate of speed than the film transport rate earlier
prior to stretching) with cooling to lock in the stretch
orientation. This locked in MD orientation produces a film having
heat shrinkability which may remain through a fabrication process
of the self-forming container of the present invention until it is
released by heat activation at an elevated temperature which for
polyolefin films is generally at about 80-90.degree. C.
[0122] Heat shrinkable film may also be made by a trapped bubble or
double bubble process of the type described in U.S. Pat. No.
3,456,044. In an alternative process for making an oriented or heat
shrinkable film, a primary tube comprising the inventive plastic
blend is extruded, and after leaving the die is inflated by
admission of air, cooled, collapsed, and then preferably oriented
by re-inflating to form a secondary bubble with reheating to the
film's orientation (draw) temperature range. Machine direction
(M.D.) orientation is produced by pulling or drawing the film tube
e.g. by utilizing a pair of rollers traveling at different speeds
and transverse direction (T.D.) orientation is obtained by radial
bubble expansion. The oriented film is set by rapid cooling.
Suitable machine direction and transverse direction stretch ratios
are from about 3:1 to about 5:1.
[0123] Films of the present invention may be monolayer or
multilayer films or sheets generally of 1 to 20 mils. Multilayer
films may have a variety of thicknesses which may be determined
according to the desired film or container properties and without
undue experimentation.
[0124] The side wall and connecting wall panels, where desired, may
employ one or more oxygen or moisture barrier layers. These barrier
layers may be of any desired thickness, but typically thicknesses
are between about 0.1 and about 0.5 mils. Thinner barrier layers
may not perform the intended functions and thicker layers do not
appreciably improve performance.
[0125] In the barrier layer embodiment of this invention the outer
thermoplastic layer of the enclosing multilayer film is on the
opposite side of the core layer from the inner layer, and in direct
contact with the environment. In a preferred three layer embodiment
of the invention this outer layer is directly adhered to the core
layer. Since it is seen by the user/consumer, it must enhance
optical properties of the film. Also, it must withstand contact
with sharp objects so is termed the abuse layer and provides
abrasion resistance.
[0126] Following are examples and comparative examples given to
illustrate the invention. In all the following examples, unless
otherwise indicated, the heat shrinkable films were produced
generally utilizing the slot cast apparatus and method described
above. In the following examples, all layers were extruded
(coextruded in the multilayer examples) as a cast sheet which was
cooled upon exiting the die e.g. by contact with a chilled drum.
This cooled sheet was then reheated by contact with further roller
drums which were internally heated by oil (heated water could also
be used as well electric induction heating) to the draw temperature
(also called the orientation temperature) for axial orientation
accomplished by pulling the sheet with thinning in the machine
direction using differential speed with cooling accomplished by
contact with another chilled roller to produce a heat shrinkable
film. All percentages are by weight unless indicated otherwise.
Example 1
[0127] In Example 1, a uniaxially stretched, heat shrinkable,
monolayer film was made and its physical properties tested. A film
comprising 70 wt. % of a cyclic olefin copolymer commercially
available from Topas Advanced Polymers GmbH under the trade name
Topas 8007F-400 was blended with 30 wt. % of a conventional
ethylene octene-1 copolymer commercially available from The Dow
Chemical Company under the trade name Attane NG 4701G (hereinafter
COC:EAO blend). This blend was melt plastified in an extruder and
extruded through a slot cast die at a temperature of from
180-250.degree. C. onto a chill roll (temperature .about.55.degree.
C.) and subsequently uniaxially oriented in the machine direction
by a slot cast MD stretch orientation process similar to that
described above at a stretch orientation temperature of
.about.85.degree. C. The orientation ratio in the machine direction
was 3:1. There was no transverse orientation stretching applied
apart from passage of the film through the machine direction
rollers. A sample of this film was tested for physical properties.
At 90.degree. C. the MD/TD heat shrink was about 50%/2%, and the
shrink force was 324/13.5 grams (measured using a heated Instron
Tensile property tester). This film was also used to form a heat
shrinkable connecting wall panel by making a single fold and
inserting and heat sealing between two nonshrink panels each of
which having a multilayer structure of PET/tie/Al foil/tie/sealant
where a cast, tentered, biaxially stretch oriented and annealed
polyester terephthalate film is adhesive laminated to an aluminum
foil layer with is adhesively tied to a polyolefin sealant layer.
These panels are believed to have essentially no free shrink at
90.degree. C. (and no shrink force either). Each panel is about 3.5
mils thick.
[0128] A pouch container is formed from two panels, each of which
are about 160 millimeters (mm) wide and 130 mm high made from the
multilayer structure described above, and a connecting wall heat
shrinkable film, as described above, is cut to be about 160 mm wide
and 76 mm high. This connecting wall film is folded in half and
positioned between the two nonshrink panels as depicted in FIG. 6
and then all three films are heat sealed together along the side
edges with the bottom edges of the heat shrinkable connecting wall
heated sealed to opposing panel bottom edges to create a three
sided pouch container with a single gusseted bottom. The heat
shrinkable connecting wall is positioned so that its uniaxial,
machine direction, stretch/shrink is along an axis that extended
from one side wall edge where the two panels meet to the opposing
side wall edge where the opposing panel side walls meet similar to
the embodiment shown in FIGS. 5-9.
[0129] This three sided pouch container of the invention may be
laid flat which is ideal for shipping and storage taking up very
little space. A pouch similar to that described above had its heat
activated, self-forming properties tested by adding hot water
(175.degree. F./79.degree. C.) inside its compartment. The
container immediately self-formed by contraction of the connecting
panel thereby drawing the opposing pairs of side wall edges toward
each other creating a stand up configuration having a stable base
connected to and supporting the side wall with an expanded
compartment volume. This transformation into a stable stand up
self-formed container was completed within a few seconds (less than
about five seconds). Upon emptying the pouch of water, the pouch
maintained its stand up configuration having a stable base and
resisted any return to a folded condition. Thus, at ambient
temperature a permanent, non-reversible, change in the shape
configuration from a flexible, lay flat condition to a more rigid,
stable, stand up configuration occurred.
Example 2
[0130] Another container of the present invention was fabricated,
as for Example 1, except with the following changes. The pair of
nonshrink side wall panels was replaced with a different multilayer
panel material which utilized unoriented PET. These panels were 5
inches high and 7 inches wide and also used a single gusset but
having a fold 21/4 inches from the bottom edge. After heat
activation, the bottom connecting wall shrank, however the
container base was slightly distorted due to the low softening
point of the material used in the sidewall relative to the heat
activation temperature and coupled with the deep gusset fold and
shrink forces attendant to the shrink film utilized.
Example 3
[0131] Another container was made, as described for Example 2,
except this container used nonshrink side wall panels which were
approximately 5 inches high by 6 inches wide and a single gusseted,
connecting panel with a 11/2 inch fold. The side wall panels and
connecting wall utilized the same materials as for Example 2. The
container of example 3 was heat activated as for Example 2. There
was much less distortion of the base of the example 3 container
which result is believed due to use of a shorter fold depth in
combination with a shorter panel width. The self-forming container
of Example 3 was also equipped with a plastic, double track,
reclosable zipper of the type which are commercially available from
several manufacturers.
Example 4
[0132] In Example 4, another uniaxially stretched, heat shrinkable
film was made using the equipment and conditions similar to those
for Example 1, except that the COC:EAO blend used in the connecting
wall heat shrinkable film was replaced with 98 wt. % of a
styrene-butadiene-styrene copolymer that is commercially available
from Chevron Phillips under the trade designation "K-resin KR52"
blended with 2 wt. % of a styrene-butadiene-styrene copolymer
containing slip and antiblock additives (hereinafter SBS blend),
and the extrusion temperatures were 180-200.degree. C., the chill
roll quench temperature was 30.degree. C. This properties of the
film made from this blend were measured. At 90.degree. C. the MD/TD
heat shrink was about 68%/-3% and the shrink force was 84.6/2.9
grams (measured using a heated Instron Tensile property
tester).
[0133] This heat shrinkable SBS film was cut into a rectangular
panel of dimensions 63.5 mm high.times.180 mm wide with the machine
direction shrink being in the lengthwise width (i.e. the longer
dimension). This heat shrink connecting wall panel was folded
lengthwise upon itself and place between two nonshrink side wall
panels of 130 mm height.times.180 mm width which is configured
generally as shown in FIGS. 5-9 of the drawings. The side wall
panels had a 6.75 mil thick white pigmented, multilayer film
construction which included a polystyrene film layer, an oxygen
barrier layer, and a polyolefin sealant layer. The sidewall sheets
were measured to have 0% shrink at 90.degree. C.; an average
thickness of about 10.3 mil; and an average MD/TD Young's modulus
of about 1553/1638 MPa. The three pouch container components (i.e.
two nonshrink side wall panels and a connecting wall heat
shrinkable film) were heal sealed together to form a self-forming
container as a pouch having a bottom single gusseted heat
shrinkable connecting panel. This pouch was then subjected to
elevated temperatures to heat activate the self-forming properties
whereupon the pouch self-formed by shrinking of the connecting
panel into a stand up configuration having a stable base similar to
that depicted in FIGS. 1-4. In this particular embodiment a stable
base was formed having a higher machine direction (M.D.) shrink
with a slight growth in the transverse direction (T.D.) which is
attributable to them SBS material used in the connecting wall which
tends to dimensionally expand in the cross direction to the
uniaxial shrink direction. At the high test temperature the
connecting wall could be manually stretched, but upon cooling to
ambient room temperature the configuration stabilized and resisted
further stretching.
Example 5
[0134] In Example 5, an inventive, self-forming container was made,
as described for example 1 above, except that the nonshrink panel
walls utilized a blue pigmented high-impact polystyrene multilayer
film similar to that described in Example 4. These side wall panels
had dimensions of 4 inches in height and 6 inches in width. These
sidewall sheets were measured to have 0% shrink at 90.degree. C.;
an average thickness of about 12.5 mil; and an average MD/TD
Young's modulus of about 1633/1634 MPa. The same COC:EAO blend
connecting wall heat shrinkable film was used, although a double
gusseted connecting wall structure was made using a 6 inch wide and
31/2 inch high film, folded into an inverted "W" shape having fold
lines which are 7/8 inch above the bottom panel edges and similar
to the configuration depicted in FIGS. 10-14 of the Drawings.
[0135] The inventive container of example 5 had an interior
compartment into which instant oatmeal was added with water. The
oatmeal and water containing pouch was set up into a microwave
oven. The container was subjected to microwave heating on its high
setting (full power) for 60 seconds causing heat activation and
self-forming of the container along with cooking of the instant
oatmeal. Upon removal from the microwave, the oatmeal was stirred
with a spoon. The container was intact with a stable bottom and a
compartment containing an expanded volume. Upon removal of the
contents of the self-formed container, the stable expanded
configuration was maintained and the container was not collapsible
at ambient temperature. Advantageously, the double gusset created a
more voluminous shape which may be characterized as a bowl, cup, or
box-like as shown in FIGS. 15-17.
Example 6
[0136] Another container was made, similar to that described above
with respect to Example 5, except with the following changes. The
side wall panels were formed from a multilayer structure having a
polyolefin sealant, biaxially oriented and annealed polyester
layer, and other polyolefin layers. The sidewall material was very
flexible and typical of that used in many commercially available
standup pouches. The side wall panels had a thickness of about 51/2
mils and each panel was about 4 inches in height and 61/2 inches in
width. The same connecting wall material was used as for Example 5
with a similarly sized double gusset having the same fold line
located 7/8 of an inch above the bottom edge of the panels and the
connecting wall material matched the width of the panels (61/2
inches).
[0137] The container of example 6 was self-formed by heat
activation using hot water as described in Example 1. Following
heat activation, the container connecting wall shrank, pulling the
opposing sets of paired side wall edges towards one another
creating an expanded internal compartment and forming the container
into a stand up configuration having a stable base connected to and
supporting a continuous side wall made from the two panels. This
configuration was not collapsible to the preform state although the
side wall panels remained flexible. The appearance of this expanded
formed stable container with similar to that depicted in FIGS.
15-17.
Example 7
[0138] Another self-forming container was made similar to that as
described above for Example 5, utilizing a similar nonshrink side
wall made from similar panels. A polyolefin multilayer blown film
was substituted for the connecting wall material. It is believed
that this blown film had little shrink force and a relatively low
free shrink value at 90.degree. C. It was made by a simple blown
bubble process. A 4 inch high and 6 inch wide, double gusseted base
construction was used. The container was heat activated by heating
water in its internal compartment for about 60-70 seconds in a
microwave oven on the full power (high) setting. A stable base
supporting the side wall in a stand up container configuration was
formed and maintained after removing the heated water return of the
container to room temperature. The formed container was not
collapsible to the pre-forming flat state. The increase in volume
of the internal compartment after forming was not as expanded as
for the container of Example 4. It is believed that the use of
blown film which has little shrink force resulted in only a small
expansion of the volume relative to other embodiments of the
invention which utilize shrink films for the connecting wall which
have been made by cold drawn or high shrink force inducing stretch
orientation methods.
Example 8
[0139] Another example of the invention may be made as described
for Example 1 with the following changes. The sidewall may have a
51/2 inch height with a lay flat width of the container being 61/4
inches and utilizing a single gusseted nonshrink material having a
height of 31/2 inches which may be folded once so that a fold line
of 1.75 inch from the bottom edge of the container is maintained.
The material used for the gusset in Example 8 is the same material
as that used for the side wall. In addition, a machine direction
oriented, heat shrinkable shrink band may be inserted adjacent to
the bottom edge of the container between the gusset folds and
sealed at either end to the perimeter side at the opposing side
wall edges. This shrink band is similar to that is depicted in
FIGS. 26-29, except that side wall panels here are integral with
the outer layers of the band depicted in the figures.
Alternatively, the shrink band of those figures could be inserted
and sealed along the container bottom or within the interior of the
sidewall or at any point between the bottom and the top, or at the
top. Upon heat activation, the shrink band contracts causing a
deformation of the sidewalls creating an expansion of volume
forming an internal compartment. Upon cooling this change is
permanent and irreversible at room temperature.
[0140] Those skilled in the art of manufacturing paperboard, and
polymeric film packaging including stretch oriented films know of
different and various processes of such manufacture and the present
inventive films include uniaxially and biaxially oriented or
stretched films regardless of the method used for their production
as well as unoriented or unstretched films including slot cast and
hot blown films and other sheet materials such as paperboard.
[0141] Films useful with the present invention may also be
optionally crosslinked by irradiation e.g. at a level of 2-6
megarads (Mrad) after biaxial stretching (which irradiative process
may be referred to as post-irradiation), in the manner generally
described in Lustig et al, U.S. Pat. No. 4,737,391 which is hereby
incorporated by reference. Films may also be corona treated or
plasma treated or treated by other known radiative processes to
enhance or alter or add desired properties as is known in the
packaging arts.
[0142] These examples are not exhaustive and other features and
properties of the other pouches illustrated herein in the Figures
can be applied.
[0143] The features of these embodiments illustrate that a variety
of shapes, sizes and configurations may be employed in the present
invention and may be made using non-peelable or peelable polymeric
films with or without metal foil layers or tear initiators.
[0144] In another embodiment of the invention, a heat shrinkable
connecting wall itself has heat shrinkable side wall panels which
are in turn adhered to nonshrink exterior side walls to produce the
same opening effect with added bowing along the side wall from the
heat shrink forces applied through the shrinkable side wall panel.
The shrink and not shrink side walls may be adhered to one another
through use of adhesive lamination. or corona treatment and
irradiative attachment for example by use of an electron beam
curing unit.
[0145] The inventive container in another embodiment is used as a
retort container which forms a "can-like" shape in a retort chamber
during heating.
[0146] In yet another embodiment, both top and bottom of the side
walls are connected by heat shrinkable films which are preferably
attached by single or multiple folds or gussets to produce a
symmetrically shaped container or can/box like appearance. This
embodiment may also be display on its side if desired with the
connecting walls located on the sides.
[0147] Advantageously, the present invention may be used to package
a variety of products including e.g. dry ramen noodles, dry rice,
dry soup mix, macaroni and cheese mixes, gelatin powder, cocoa,
instant coffee, backpacker meals, oatmeal, grits, etc. and these
types of foods may be shipped in a closed, sealed compact state
which conserves space and then expanded by heat shrinking the
connecting panel e.g. by addition of hot water to the contents
thereby creating a stable bowl or cup container which has
sufficient rigidity to enable serving and access. Thus, the
inventive package takes on multiple shapes, such as flat and
rounded bowl, and has means to transform from one shape or
configuration to another shape or configuration. Thus, the present
invention provides a self-forming container without any necessity
for microwave susceptors, stays, expandable polymers or
microencapsulated materials. In one embodiment, a consumer may just
add hot water to simultaneously reconstitute the food product and
create a stable bowl-like shape for serving and/or eating. In
another embodiment, an expanded container is used by a processor
for economical shipping and storage followed by self-forming for
ease of filling. In yet another embodiment, the processor enjoys
the benefits of small volume storage of the unfilled containers
while permitting the processor to self-form the container and
provide a stable filled container with a variety of articles from
soup to nuts, to retorted foods and packages to containers for
perishable or nonperishable food or non-food articles.
Embodiments of the Inventions
[0148] Various embodiments have been described above. Although the
invention has been described with reference to these specific
embodiments, the descriptions are intended to be illustrative and
are not intended to be limiting. Various modifications and
applications may occur to those skilled in the art without
departing from the true spirit and scope of the invention as
defined in the appended claims.
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