Note: Descriptions are shown in the official language in which they were submitted.
02 1009
FIELD OF THE INVENTION
The present invention relates to p~pcorn and easily
opened containers therefor and more par~icularly to ~uch a
combination that is suitable for use in a ~icrowave oven.
BACKGRO~ND OF THE I~VENTION
S A variety of popcorn containers are known in which corn
kernels can be popped on or ln a conventional ~tove. One ~uch
container is described in U.S. Patent ~o. ~,110,233 to Mennen
entitled "~pparatus for Shaping Metal Foil.~ Container~ of thi~
general type are, however, not suitable for use in ~icrowave
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; 10 ovens where foil is prohibited. Accordingly, paper containers~
have been devi~ed for popplng corn in microwave ovens, an
:~example belng U.S. Patent ~o. 3,973,045 to Brandburg et al
entitled "Popcorn Package for Microwave PopcornO ~ It should be
no~ed that these contalners ~re specially constructed for ~ ;
microwave u~e and generally are~ not usable in o~her types of ~
: ovens because the paper will burn.: ~ . :
:Presently:known paper containers for popcorn ~ :
ingredient5 do,~owever~, have ~ignificant drawbacks. They aIe
permeable by the~included~hortening or oil and ~re thus 6u~ject
~: 20 to staining and require~refrigeration to prevent:the ~igratlon
o f :the ~hor~en1ng to the out~ide of ~thè paper. If refrigerated
prior to use, they tend to~condurt heat through the oven floor,:
~ thus creating a cold:~pot and reducing the;effectiveness of the
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popping action. Moreover, known paper containers tend to be
permeable by steam, thus allowing steam to escape with the
result that the temperature within the container is lowered and
the popping action is less effective, leaving a higher pro-
portion of unpopped kernels. If the container is not permeable
by steam it suffers from the disadvantage that the steam, if
allowed to remain in the container, may result in the popped
kernels becoming too chewy within a very short time. Paper
is also less easily torn when compared to metal foil and is
therefore difficult to open, especially when hot. Relatively
complex and costly to manufacture closure arrangements are
therefore required to overcome this problem.
SUMMARY OF THE INVENTION
Broadly the present invention provides for use in a
microwave oven, a shelf-stable combination of an easily opened
bag and a mi~ture of edible popcorn ingredients for popping.
The bag comprises a front panel, a back panel and
inwardly folded gussetted side panels, the panels being
arranged such that the bag can be flattened with said gussets
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closed and the front and back panels contacting each other
along a center strip~between said gussets. The bag then forms
a top edge having the least thickness along said center strip.
The panels comprises structural outer layer such as
paper and an inner layer that is non-wicking with respect to`
grease and transparent to microwave energy. Portions of said
; panels constitute seal means comprising a coatlng that is~a
part of said inner layer~and is sensitive to pressure and heat.
The seal means are formed by pressure and heat along said ~
top edge such that opposing surfaces of said inner layer are
adhered to each other~relatively more~securely along first
;~ seal areas corresponding to said gussets and relatively less
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securely along a second seal area corresponding to said
center strip. The seal means are effective for (1) closing
said entire top edge prior to heating of said ingredients
to cause popping and maintaining said top edge in a closed
condition for a part of said heating to cause steam to be
retained during heating and popping of said ingredients until
a predetermined internal pressure is reached, (2) opening
automatically along at least a portion of said second seal
area in response to said predetermined internal pressure
during popping to allow steam to escape, and (3) opening further
along at least a portion of said first seal area in response
to being pulled at diagonally opposite corners formed by said
gussets.
The structure is disposed wlthin said bag and com-
prises shortening and corn kernels having a moisture content
of at least about 11.5 percent by weight, whereby sufficient
internal pressure is generated at a temperature of not more
than 350 to 450F. to open said seal along at least a portion
of said top edge.
In another embodiment of the present invention the
bag has a kraft paper outer layer and an inner layer comprising
polyethylene terephthalate and covering the entire surface
exposed to the interior of said bag.
; In another aspect the invention popcorn ingredients
may be positioned adjacent said bottom panel and comprise corn
kernels and a shortenlng~that is a solid at room temperature,
said kernels having a moisture content of about 13 to 14 percent
by weight whereby said predetermined pressure is reached prior
to the last 30 seconds of sald popping~process.
The present invention provides a combination of popcorn
ingredients and a~container therefor suitable for microwave use
that overcomes many of the problems referred to above. In general,
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~`~ the bag is of a conventional standup configuration, having a
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bottom panel, front and bac~ panels, and inwardly folded gus-
seted side panels. An edge of the bag opposite the bottom
panel can be folded flat. The bag is made of paper with
an inner layer of non-wicking material, preferably a poly-
ester, such aspolyethylene teraphthalate (PET). An adhesive
coating, preferably also polyester, is applied to the inner
layer forming a peelable seal along the top edge.
The popcorn ingredients within the bag include corn
kernels and a shortening, the shortening preferably being a
solid at room temperature. The moisture content of the kernels
is at lea8t about 11.5 percent 2nd preer~bly bet~een 13 ~nd 14
percent. The peelable ~eal ha8 ~ufficient 6trength to wit~tand
the internal ætea~ pre~ure generated ~y thi~ ~oistUre ~ontent
for at lea~t one-half ~f the popping process. Preferably, the
bag will vent at tne top ~eam before the process is completed to
allow 6team to escape. Venting of ~te~ for at least the last
30 secondc ~ the process is pre~erred.
In one preferred ~or~ of the invention there i~ a
center ~trip extendIng vertically alon~ the bag between the
gusset~ where the ~ront and back panel~ contact each other when
the bag is folded flat. The ~eaI;for~ed by heat and pre~sure at
the t~p edge ha~ ~he leas~ strength a~long t~e center ~trip where
ther~ are ~ew layer-~o~aterial~ ~he p~rtion o~ th~ ~eal
corresp~nding to the center ~trip is therefore the portion where
venting usually occurs. This venting ac~i~n allows ~tea~ to
es~ape 80 that t~e~popped corn kernel8 will not become too
chewy.
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Other eatures;and advanta9e~ of t~e present invention
will become apparent~from~the foIIowing detailed~de cription
which, taken in~conjunction; with the acc~panyi~g drawings,
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`~ illustrates, !by way of e~a~ple, the principles of the
; invention.
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BRIEF DESCRIPTIC>N OF THE DRAWI~GS
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FIGIl~E 1 is a view of the front and top ~partially
broken away ) of a bag and contents, in accordance with the
invention, p~sitioned within a ~icrowave oven;
FIG. 2 is a cross-sectional view of the bag and
contents taken along line 2-2 of FIG. 1;
FIGS. 3 and 4 are partial.ly broken away perspective
side view~ of the bag and cont~nt~ as the popping process beyins
and as it nears completion, respectively
FIG. 5 .is a ~ros~-~ectional view showing the material
of which the bag is ~ade;
FIG. 6 is -a top view showing the top edge of the bag,
the thickness of the layers being exagerated for clarity; and
FIGS. 7 and 8 are top views of the bag being opened.
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DESCRIPTIO~ OF T~E PREFERRED EMBODIMENT
A popcorn bag 10 and it6 conten~s 11, suitable for~icrowave use and constructed in accordance with the pre~ent
inventi~n, i6 shown in Figures l-~B of the accompanying
drawings. The general configuration of the bag 10 is of the
conventional standup type, having a flat rectangular bottom
panel 12, rectangular ~ront and ~ack panels 14 and 16, and
inwardly folded gusseted side panels 18.
The ingredients 11 are placed inside the bag adjacent
to the bottom panel 12. These ingredients 11 consist
principally of corn kernels, shortening and ~alt. Preferably,
the kernels are all of appro~imately eq~al BiZe 80 that
æubstantially all kernels will pop uniformly and within a narrow
time frame, the popping time in a ~icrowave oven being dependent
upon kernel ~ize. Since popping is attributable to the moiæ~ure
content, it is important that there be ~ufficient:moisture.
There should be at least 11.5 percent m~isture content by weight
in the kernels and a content of 13 to 14 percent is better, 13.5
being optimum. Too little moisture results in small popped
kernels the density of which is too high to produce the fluffy
texture desired.
: The ingredients 11 also include a ~hortening that is a
solid a room temperature. ~o refrigeration i5 reguired and the
~; product is thus ~hel:f-stable. Ani~al fats ~ay be desirable
: : : 25 because they tend to generate higher temperatures for better
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02 1009
~ he bag 10 i~ forDed o~ an outer layer of a ~ingle
~heet o~ kraft paper 20 ~Eee ~ig. 5) ~rea~ed with a coDmercially
available ~tain inhibitor. An inner ~ayer 22 i~ a polyester
film such as polyethylene ter~phthalate, ~n example bei~g O-L
5 Mylar fil~ available fro~ DuPont. Alternative inner layer
Daterials would be coextruded and po~sibly other ~ulti-ply film~
of polyethylene terephthalate, as outer plies, wit~
polycarbonate (~uch as Le~an ~ade by General Electric~ ~nd
ethylene vinyl alcohol as ~iddle plies. The preferred thickne6s
10 of this ~ilm 22 is a~out 0. 5 to 1. 0 ~il6 and it ~hould be
capable of withstanding temperatures of 350 to 450 F., as
will be encountered i~ a ~icrowave oven, without melting ~r
:~ ot~erwise conta~inating or i~parting ~ vor to the ingredient~ 11
! A coating sensi~ive to a combination of heat and pressure, commonl~
15 referred to as a heat:seal coating, (not identified separately in the
drawi~gs) 18 applied to t~e e~p~sed intericr ~orface of the film
22. The c~4tlng is also p~lyethy~lene terephthalate, being
chemically~imilar to the undeslying fil~ 22, but t~e coating i5
amvrphous and theref~re ealable whereas~the inner layer is
20 crys~alline.
All of the æeams~f~the bag~10 ar~ ~ealed ~y the~heat
eal ooati:ng 24.:~and all ~ea~s:escept that e~tending al~ng a top
edge 26 ~pposite the bottom panel 12~bave an additlonal~backup
eal (not ~hown in~the~d~rawings)~here the paper 20;;i-:n~t
25 covered by the film;22~and the pap-r ~ur~aces are~glu~ed
togeth~r. Thic i~accompll~hed al~ng a vertical 6eam 28
extendlng up the~back panel~l6~, a~ ~h~wn in Flg. 6, by where tw~
:~ adjoining ends~of the~paper 20 ~eet.~ One edge 30 i8 folded over
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02 lO09
at the point of overlap to for~ a fil~-to~ilm seal on the part
of the overlap closest to the interior o~ the bag lO. The
remainder of the overlap portion for~s a paper-to-paper seal.
Since the paper-to-paper fieal is the outer seal and the
5 fil~-to-film seal is an inner seal, the entire interior surface
of the bag lO that is exposed to the in~redients 11 is covered
by the fil~ 22 and the ingredients ll cannot come into direct
contact with the paper 20. The fil~ 22 i6 imp~rmeable to the
shortening which would otherwise tend to seep through the paper
lO 20 at room temperature causing discoloration and an unsanitary
: condition, particularly if not refrig~rated. ~n oxygen barrier
is also formed by the film 22, thereby increasing the shelf-life
of the ingredients ll. The backup seams insure that the
contents ll ca~not escape if one of the film-to-film seals,
15 which are not as seron9 as the glued paper t~-paper ~eals,
hould fail, especially i~ the presence of the internal steam
-: : : pressure generated during popping.
; When the bag 10 is ready for use by the consumer, lt is
placed in a microwave oven 32 (as ~hown in Fig. 1) with the
20 botto= panel 12 of t~e bag re5ting on the oven f}oor 34, as
hown in Fig. 2. As:~the~:mlcrowave ~nergy is absorbed by the
: corn kernels, their moisture content turns to steam, causing
~: popping, and the steam beglns to fill the bag lO causing it to
~; assume an expanded upright cvndition, first as s~own in Fig. 3
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~: and then a~ shown i:n Fig. 4. Lower portions of the gussetted
~ides 18 ~pen ~ut the top edge 26 of~the bag lO~remains ~ealed
against this ps~essure, at least during~he earlier stages of the
popping process. The ~team cannot escape from the bag lO
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because of the Mylar film 2~. If the stea~ were allowed toescape prematurely, the product volume would be too low and the
popped corn would be too dry and over~ooked. It should be noted
that the expansion of the bag 10 due to the internal ~team
pressure creates a vertical space of considerable height above
~he bot~om panel 12 to per~it free and unrestricted popping
action, thus reducing ~he number of unpopp~d kernels.
As mentioned above, the peelable ~eal alony the ~op
edge 26 of the bag 10 is the ~ost easily separated fil~-to-film
seam, this being the result of the ~anner in which the heat seal
coating is applied and processed. In addition, there is no
backup paper-to-paper seam alo~g the top edge 26~ Accordingly,
as the pressure builds up the seam along the top edge 26 will be
the first to open. The ~trength of the top edge seal is ~uch
that, with corn kernels having a moi~ture content of 11~5
percent or more by weight, that sea~ will remain sealed for at
; least the f irst one-half of the poppin~ ti~e.
When the bag 10 is remov~d from the oven 32, the top
edge~seal provides a ~uick and convenient arrangement or
opening tbe bag 10. As shown in Fig. 7, diagonally opposite
corners of the bag 10 are grasped and pulled apart. To:~ more
ully open the bag 10, the two remaining diagonally opposite
corner~ can then be pulled in the same manner, as shown in Fig.
8. Thi~ arrangement is highly sanitary since the person opening
the bag 10 need not at any time touch the i~side ~urface os the
ingredients 11. :Opening can be ~ccomplished when the bag 10 i~
hot, w~ich i~ particularly advantageous if the steam is still
: contained within the bag.
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Although the seal along the top edge 26 may be ~ade 80
as to remain closed throughout the entire popping process, it is
advantageous that it open during the last one-half of the
process, preferably before the last thirty ~econds, to allow
steam to escape. It is then possible to allow the bag 10 to
stand without attention after the popping process has been
completed, as is likely to happen in the event that the
~icrowave oven 32 is equipped with a timer. If the bag 10 were
allowed to 8tand for only a few ninutes with the steam trapped
in8ide, the popcorn would become undesirably chewy.
It should ~e noted that the bag 10 has a center strip
36 where the front panel 14 and the back panel 16 come into
contact with each other when the bag is folded flat, as shown in
Fig. 6. Whereas there are only two thicknesses of the inner and
outer layers in the center strip 30, there are more thicknesses
in the area of the gussets 18. On one side where the seam 28
extends vertically up the bag 10 across one of the gussets there
are six thicknesses. Since the seal along the top eage 26 is
for~ed by the application of pressure and heat, it will, in the
absence of special provisions to eliminate this effect, be less
~ecure along the center 6trip 36 wnere the pressure is least.
Therefore the center portion of the top edge 26 is the primary
venting portion of the seal, although in exceptional cases other
portions of the top edge seal ~ay vent first. The most frequent
location for ~enting to take place is indicated in Fig. 6 by the
letter "V" and i8 adjacent to the side of the bag 10 where there
are six thicknesses, this being the area in which there is the
greatest reduction in the width of the top edge thickness.
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~ 02 1009
As will be appreciated from ~he above description, the
present invention provides a convenient and easy to use popc~rn
ingredient and container combination ~uitable for use in
microwave ovens. The uni~ue c~nstruction of the bag, with ite
coated inner layer, provides a convenient and sanit~ry
easy-openin~ feature and provides for ~elf-venting of the
steam.
While a partic~lar form of the invention has been
illustrated and described, it will be apparent that various
~odifications can be made without departing from the spirit and
the scope of the invention. Acsordingly, it i8 not intended
that the invention be li~ited, except as by the appended
claims O
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