Note: Descriptions are shown in the official language in which they were submitted.
PLASTICS MATERIAL FILM SHEET HAVING A
_ PRESELECI'ED WE _ NED AREA
This invention relates in general to new and
useful i.mpro~ements in the manufacture of packages, and
more particularly to a plastic material film sheet par-
ticularly adapted to form a package for foods and having
a rupturable seal between two compartments throuyh which
one of at least two foods passes to permit mixing within
the package.
~ This invention generally relates to the maklng
: ~ of packages with rupturable seals of the general type
~ 10 disclosed in my prior U.S. patent 3,608,709.
; In the past, it has been necessary to adhesively
:~ bond tow~films together with the bond between the films
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in certain areas being weaker than in other areas to as
to define a preselected weakened area which becomes part
of the seal. Not only have such films been difficult to
form, but also the strength of the bond surrounding the
weakened area has not been sufficiently predictable.
In accoxdance with this invention it is proposed
to provid what is truly a single sheet of thermoplastic
that has a localized area of resist, which divides the
sheet at intermediate portions into two discreet thick-
.nesses of the same material and which two discreet thick-
nesses cannot be fused togethPr at a later date due to the
presence of the resist material. In other words, the
resuItant sheet of thermoplastic material that has been
formed from two thicknesses of the same material has an
integral self bond therein so that for all practical
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purposes, except in the area of the .resist material, is
a single thickness material.
In my prior U.S. Patent 3,608,709 the sheet of
thermoplastic material was a laminated sheet and the -two
layers were not unitarily bonded together such as being
fused or welded so as to constitute a single thickness
material except in the resist material area. In all
instances of my prior U.S. Patent 3,608,709 the two
la~ers of the larninat.ed sheet had to be adhesively bonded
together. Inasmuch as adhesive bonds have a tendency to
peel, certain of the packages failed to open due to the
continued separation of the laminated sheet on one or both
sides of the resist material.
~ This invention also particularly rela-tes to
packages for food wherein two different foods may be
packaged in a single package in adjacent compartments
separated by a rupturable seal such that when the seal
is ruptured, food being transferred from one compartment
to the adjacent compartment will actually pass over the
resist material. It is therefore an important feature
of the invention to form the resist material itself of a
food grade material. The resist material itself may be a
food or be recognized as being quite compatible as a
food additive.
In accordance with this invention, it is pro-
posed to provide a first film and to apply to that first
film at preselected areas a resist. Thereafter, a second
and thinner film is applied to the first ~ilm and integra]ly
bonded thereto in all~r~s- except for the area having the
resist material thereon~ The first and second films are
so self bonded together so as to constitute a single film
having a thickness corresponding to the total thickness
of the two films and the film having weakened areas which
may be utilized in the formation of seals in packages.
The resist material may be suitably applied to
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the first film by means of printlng and the like.
The second film could be a preformed second
film which is heat bonded to the first film, or it may
be cast in place on the first film and directly bonded
thereto as it engages the first sheet. A cast second
film has a definite advantage over a preformed second
film in that in the normal formation of plastic rnaterial
films a tube is e~truded and is then blown and stretched
to a much larger diameter. Certain of this stretching
takes place at -the orientation temperature and, there-
fore, the plastic material becomes oriented and is much
stronger than like thickness cast film of the same
material. It is also to be understood that when the
second film is preformed, it must be drawn from a roll
over rollers in tension with a result that a relatively
high stress is put on the preformed second film and it
must have a much higher strength than tha-t required in
the package. Therefore~ a cast film has a positive
advantage over a preformed film.
The plastics material film sheet formed in
accordance with this invention ma~ be folded and cut to
length to form pouches which have either at the ends
thereof or in intermediate areas thereof a seal which is
aligned with and contained within the perimeter of a
weakened area and wherein when opening force is applied,
the ~ilm ahving the weakened areas therein will rupture
along that weakened area so as to effect an opening of
the pouch.
It is to be understood that the plastics
material film sheet may also be bonded to other sheets
which may be formed of other materials or plastics
materials either by heat bonding or by means of a suitable
adhesive~ -
Further, it is to be understood that the plastics
material film sheet is particularly adaptable for use in
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forming pouches for receiving medical disposables andmay employ the conventional chevron seal configuration.
In addition, the film sheet may he utilized in
the sealing of jars and the like wherein the weakened
area is annular and the film sheet is secured to the
container lip in alignment with the weakened area so
that the lid formed by the film sheet may be torn off
all except for the thin narrow part which forms part
of the seal with the container.
Another use of the film sheet is as a removable
seal for cartons and the like and as such may also function
as a label.
It is particularly pointed out here that the
resist material incorporated in the film sheet must have
the proposed of preventlng bonding together of the film
sheet in the weakened area during the formation of a heat
seal.
With the above, and other objects in view that
will herinafter appear, the nature of the invention will
be more clearly understood by reference to the following
detailed description, the appended claims, and the
several views illustrated in the accompanying drawings.
IN THE D~AWINGS:
Figure l is a schematic view showing the
manner in which the film sheet of this invention may ~e
formed utilizing two prior formed films.
Figure 2 is a schematic view similar to Figure
l and shows the film sheet being formed with the thinner
film being cast in place as an extrudate.
Figure 3 is an enlarged fragmentary sectional
view taken along the line 3-3 of Figure 2 and shows the
cross section of the film sheet.
Figure 4 is a schematic view showing the manner
in which the film sheet may be transversely folded to
form a tube which may be severed at intervals to form pouches.
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Figure 5 is a plan view of a pouch which is
formed with the tube material of Figure 4.
Figure 6 is an enlarged fragmentary sectional
view taken along the line ~-6 of Figure 1 ancl shows -the
seal area of the pouch.
Fiyure 7 is an enlarged ~ragmentary sectional
view similar to Figure 6 and shows the ruptured seal.
Figure 8 J.S a fragmentary sec-tional view similar
to Figure 6 and shows the fiLm sheet secured to another
sheet of different material in the formation of a pouch.
Figure 9 is a schematic fragmentary p:lan v;ew
of the film sheet utilized in forming a pouch for medical
; disposables wherein the seal is a chevron seal.
Figure 10 is a schematic plan view with parts
broken away in section showing the film sheet utilized
as a removable lid for a container such as a jar.
Figure 11 is a 'ragmentary sectional view
showing a carton or thelike wherein end of flaps are held
together by a seal ~ormed of the film sheet and wherein
the seal may be in the form of a label.
~ eferring now to the drawings in detail,
reference is first made to Figure 3 wherein there is il-
lustrated a plastics material film sheet having a preselected
weakened area therein formed in accordance with this
invention. The plastics material sheet is generally
identified by the numeral 10 and has a weakened area 11
defined by an internal resist layer 12. The material of
the resist layer 12 may be a food or be recognized as
being compatible as a food additive as will be discussed
hereinafter.
The film sheet 10 may be formed in several
manners including those shown in Figures 1 and 2. With
particular reference to Figure 1, a previously formed
thermoplastic film sheet 13 has the resist material 12
printed thereon by means of a suitable printing device 14.
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Then a second previousl.y formed thermoplasti.c film sheet
15, which is of the same material as the sheet 13 or
a different material which will directly fuse to the
material of sheet 13, is applied to that surface of the
film sheet 13 having the resist material 12 printed
thereon by passing the two film sheets through suitable
: heaters 16, 17 and then through a nip defined by two rollers
18. The film sheets 13, 15 t:hus become integrally bonded
together with the resist material 12 entrapped therein
as shown. It is to be understood that the film sheet 10
becomes inteyral except the weakened areas where the
resist material 12 is located.
Referring now to Figure 2, it will be seen
that the film sheet 10 may be formed in a slightly dif-
ferent manner. The separate fi~n sheet 13 is providedand the resist material 12 is applied utilizing a
printing mechanism 14 in the manner illustrated in Figure
1. Then a second film sheet 20 is extruded from a film
extruder 21 as a cast extrudate at a sufficient tempera-
ture wherein the film sheet 20 becomes integrally bonded
~ to the film sheet 13. As previously described, the
: second film sheet 20, when it is in the form of a cast
extrudate, will be much weaker than the film 15 and,
therefore, rupture of a seal may be controlle~ to be at
a much lower force.
It is to be understood that the plasticsmaterial from which the film sheets 13, 15 and 20 are
formed must be conventional thermop]astics whlch are
self bondingO More particularly, they must be self
bonding at the elevated temperature at which thermo-
plastic material is cast so that with particular reference
to the embodiment of Figure 2, the cast film 20 will
self bond to the film 13 to result in, for all practical
purposes, a single laye.r sheet as is shown in Figure 3.
The preferred thermoplastics include poly~thylene,
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ionomer resins, and polyvinylchloride. Polyethylene
is particularly advantageous in view of its cas-tin~
temperature of 610 - 640F while the ionomer resins
have a casting temperature of 580 600F.
It is to be understood that due to the hiyh
temperature of the cast film and the fact that the
cast film, as well as ~:he heated film 15 are at such
a hi~h temperature to permit self heat bonding, the
surEaces of the two films in the area of the resist
material 12, as well as the resis-t material, are hea-ted
to a sterilization -temperature and -thus are sterile~
~ccordingly, when the film 15 or the film 20 is ruptured
in the opening of a package in the manner described
hereinafter, the exposed external surfaces will be
sterile.
It has been found that exceptional results
have been obtained with hydroxypropyl methyl cellulose
USP 3CPS. This material is sold by the siddle Sawyer
Corporation of New ~ork. The chief characteristics
of this material are its recognition as a food addi-
tive by the Food and Drug Administration and the fact
tha-t it complies with all USP specifications. Further,
it can be given a Certificate of Certification for
Kosher food applications.
The above described food additive has the
capability of being put into suspension with just
water, or with alcohol. As such, it can form a thick
viscous liquid which can be diluted on the printing
machinery with the further addition of water, allowing
the pressman to adjust the viscosity as needed for
the particulax application. Since this material can
be put into suspension both in water and in alcohol,
and in other food-based products, and as itself is
recognized as a food additive, it forms a resist
which is entirely edible and could not possibly con-
taminate ~ood products.
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Other materials that are s~itable for use as a
resist and which would be acceptable for use with food
products are: methyl cellulose hydroxypropyl methyl cellulose
phthalate, hydroxypropyl cellulose, ethyl cellulose,
microcrystaline cellulose, sugar, pharamaceutical grade
shellac, pharmaceutical grade waxes, carboxy methyl
cellulose, zein, cross-linked polyvinyl pyrrolidone,
polyvinyl acetyle phthalate, cellulose acetate phtyalate,
acrylic polymers and products relating to the foregoiny.
It is also pointed out here that in the formation
of a typical pouch, the sheet film 10 would have a thick-
ness on the order of 0.005 inch with the thicker film 13
having a thic~ness on the order of 0.004 inch and the
thinner film having a thickness on the order of 0.001
inch~
~ n the formation of a typical pouch utilizing
the film sheet 10, the film sheet 10 is of a predetermined
width to form a pouch, or multiples thereof. The width
of the resist material 12 is substantially equal to the
intended width of the pouch.
The film sheet 10 is reversely folded upon
itself in the manner shown in Figure 4 and the remote
edges thereof are heat sealed together as at 22. The
sealed areas may be folded flat. The ne, result is a
tube 23.
The tube 23 may then be provided with transverse
seals 24, at intervals, and then cut, as shown in Figure
5. ~fter the resultant pouch, generally identified by
the numeral 25, has been formed, a suitable product may
be placed therein after which the opposite end of the
pouch 25 is closed by a further seal which is aligned
with and totally within the weakened area 11 defined by
the resist material 12.
In Figure 6, there is illustrated a typical
cross section through the pouch. It will be seen that
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the heat seal 26 is between the two walls 27, 28 of the
pouch and that the walls 27, 28 have free end portions
30, 31 which facilitate the opening of the pouch. As
is shown in Figure 7, when the free end portions 30, 31
are pulled apart, the wall 27 will rupture in the area
defined by the weakened portion 11 with that part of the
weakened portion 11 defined by the thinner of the original
film sheets becoming detached and remai.ning fused to the
wall 28.
It is to be understood that the illustrated
pouch 25 is only one of the numerous usages to which a
film sheet, such as the fil.m sheet ].0, may be placed.
Refe:rring now to Figure 8, it will be seen that
the film sheet 10 is illustrated in the formation of a
; 15 pouch 35 by bondi.ng it to another sheet materal, generally
identified by the numeral 36. It is to be understood that
the sheet material 36 could be in the form of paper, paper
film laminates, film metal foil laminates, etc. In the
illustrated embodiment, the other sheet 36 is shown as
a laminate including an inner layer 37 and an outer layer
38 with the inner layer being sealed to the weakened area
11 of the film sheet 10 by a seal 40 which may either be
an adhesive seal or a heat bonded seal.
In Figure 9, there is schematica]ly illustrated
a conventional type of pouch, generally identified by
the numeral 41 which may be utilized for storing and
shipping medical disposables. The pouch 41 is provided
with.a chevron seal, generally identified by the numeral
42. In accordance with this invention, at least one
layer of the pouch 41 is in the form of the film sheet
10 while the other layer may be in the form of a sheet,
such as the aforedescribed sheet 3~. The weakened area
11 of the :Eilm sheet 10 is illustrated as being of a
chevron configuration and has centered therein a suitable
bond 43.
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Referring now to Figure 10, it will be seen
that the film sheet 10 may be utilized as a lid or other
type of cover for containers~ ~ conventional. jar 44
having a sealing lip 45 is il]ustrated. The lid, which is
identified by the numeral 46, is suitably bonded to the
- lip 45 by way of a seal 47, which may be an adhesive
bond or a fusi.on bond and which is aligned with the resist
12 which is illustrated of a circular configurat.ion. The
lid ~6 is provided with a suitable tab 48 to facilitate
the progressive tearing of the lid material in alignment
with the bond 47 in the same manner as is shown in Fi.gure,7.
In Figure 11, there is illustrated a conventi.onal
type of carton, generally identified by the numeral 50.
The carton 50 has walls 51, 52 and 53 with the wall 52
having an inner closure flap 54 and the walls 51 and 53
having. outer closure flaps 55 and 56, respectively. A
closure element, generally identified by the numeral 57,
is suitably bonded to the flaps 55 and 56 as at 58 in
alignment-with-the resist material 12 so that the closrue
element 57 may be readily removed.
It is also pointed out here that the closure
element 57 may also be in the form of a suitable label or
may merely function as a store seal, particularly if the
carton 50 contains other containers or packages.
At this time it is particularly pointed out
that the sheet film 10 is adapted to be secured to other
materials either by way of an adhesive bond or by way of
a heat bond or fusion bond. It is to be understood that
~he net result of the bonding of the two layers of the
sheet film 10 is an integral single thickness material
as opposed to a laminted material. It is further to be
understood that the resist material 12 is of a nature and
of a thickness so as to prevent self-adhesion of the
film sheet 10 in the weakened area 11 during the formation
of a fusion bond.
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It is also pointed out that the same film 10,
and the resultant seals may be used i.n a multiple
cornpartment package of the type disclosed in my prior
U.S. Patent No. 3,608~709.
It will be readily apparent that inasmuch as
the resist in each instance is a product which is com-
patible with food and is either a food or a food addi-tive
and the resist and exposible f.ilm sur~aces are sterile,
when food is packed in a package formed in accordance
with this invention and the package is either opened to
communicate two compartments or to dispense a product
by the rupture of the film to expose the resist, the
food may freely flow over the resist material without
dange of contamination.
Although only a preferred embodiment of the
invention has been specifically illustrated and described
herein, it is to be understood that minor variations may
be made therein without departing from the spirit and
scope of the invention as defined by the appended claims.
