Note: Descriptions are shown in the official language in which they were submitted.
~13383~
~ `
~ DESCRIPTION
3 C~NTAINERS FOR BEVERAGES AND THE LIKE
:i .
5 Technical Field
This invention relates to containers for flow-
able materials including liquids such as fruit juices and
the like, and to a method of canning such materials in
10 sealable containers wherein the materials are heat treated
and packaged. More particularly, it relates to tubular
wall members for forming tubular containers in which
flowable materials, e.g., a beverage such as fruit juice,
are sealed and packaged for long-term storage. In addi-
15 tion, the invention has to do with a cap or closure member
for hermetically sealing the aforesaid containers, and
~ which is capable of alleviating internal negative pres-
- sure.
; 20 Background Art
-
Heretofore, containers or "cans" for packaging
flowable or pourable materials including liquids, par-
ticularly beverages such as fruit juice and other food-
25 stuffs, have been generally formed of glass, tinplate,
~ aluminum and the like. Although these materials are
satisfactory from the standpoint of airtightness and
strength, difficulty is often encountered in disposing of
these materials after use, in a manner consistent with
30 environmental considerations, and a long-felt need has
therefore existed for a container which can be so readily
; disposed of. From the standpoint of economy of resources,
it is also desirable that containers be made of inexpen-
sive substitutes for increasingly expensive conventional
35 materials.
~k'
1~3383~
_ -2-
1 In addition, the laws in many jurisdictions
require that, in the processing of certain foodstuffs
such as fruit or fruit juice, the product be heated or
pasteurized at or above a certain temperature before
5 being put in containers and sealed. However, some food-
stuffs, for example, beverages, when processed in this
- manner will often contract upon cooling in the container,
thereby creating negative pressure, i.e., a pressure below
atmospheric. If such containers are formed of materials
10 having little rigidity such as thin aluminum, synthetic
resins or plastics, the negative pressure must be relieved
without breaking the seal in order to avoid the buildup of
unwanted stress on the container and consequent strain
leading to unsightly deformation of the container wall,
15 structural damage or even failure of the unit. Alter-
natively, if the container is made of laminated paper,
kraft paper, cup paper or other like sheet material, it
~ may not only be deformed but also, due to the pressure
y differential between the interior and the exterior of the
20 container, may rupture at the seal between the lid and
side wall, thereby exposing the contents to infection
by infiltration from without, e.g., by bacteria, mal-
odorants and the like, with resulting curtailment of
shelf storage life. For this reason, it has been cus-
25 tomary to use materials of such lower rigidity only for
containers intended, e.g., for non-pasteurized or car-
bonated beverages and the like which provide a neutral or
positive pressure within the container.
In the past, tinplate has been the material of
choice in making blanks for "tin cans" designed to with-
stand the aforementioned negative pressure due to its
greater rigidity, and for airtightness. However, tinplate
is relatively expensive compared to cup paper and the
35 newer synthetic resins and the like and also re~uires
~133837
_ -3-
-
1 greater effort in its disposal after use. Furthermore,
even in the case of tinplate, some deformation of the can
or container as a result of negative pressure cannot be
avoided. In the past, ways of coping with this problem
have included the means shown in FIG. 1 of the drawings.
In particular, end-closure 2 of can body 1 is not flat-
j tened but rather, is provided with, say, two concentric
convex circular ribs 3 and 4 to provide flexibility and
permit the closure to deform in response to the internal
negative pressure and decrease the latter, thereby prevent-
ing container wall 5 from being dented. The small degree
of deformation permitted in closure cover 2 limits reduc-
tion in the negative pressure but is enough in the case
of containers made of conventional tinplate. ~owever, in
the case of containers or cans made of thin aluminum,
plastics, cellulose-hased sheet material and the like,
this approach has.no~t proven satisfactory and does not
-~ contribute to a solution of the problem. Therefore,
containers designed for packaging materials which nor-
mally tend to develop substantial internal negative
pressures have not heretofore been made successfully
of these materials. Other previous attempts at solving
the foregoing problems, as exemplified in U.S. Pat.
Nos. 1,963,795; 1,987,817; 2,012,213; 2,027,430;
25 2,115,340; 2,623,681; 2,982,457; 3,089,630; 3,105,765;
i 3,160,302; 3,247,869; 3,400,853; 3,457,130; 3,687,351;
and 3,716,435, have likewise not proven adequate for their
solution.
Accordingly, it is an object of the present
invention to provide a tubular member or element which
defines the wall of a fully airtight and easily disposable
container for sealingly packaging flowable materials
including beverages and other foodstuffs for long-term
storage.
;
~33837
-4-
1 Another object is to provide an improved tubular
container wall member or element which effectively
protects the contents of the container from impregnation
by offensive odors and infectious organisms from without,
and which is made of relatively inexpensive and easily
disposable materials.
Another object is to provide an improved tubular
~ container and a process for hermetically sealing therein a
¦ 10 flowable material such as a beverage or other foodstuff,
3 e.g., fruit juice, which are adapted to respond to and
S relieve internal negative or sub-atmospheric pressure
without breaking the seal.
Another object is to provide a container cover
or closure member adapted to respond to and relieve
internal negative pressure created, for example, by
~ thermal contraction of the contents of the container,
; without breaking the seal.
Another object is to provide a container cover
or closure member designed so that internal negative
pressure created, for example, by thermal contraction
within the container, causes the closure cover to become
; 25 depressed inwardly to an extent not exceeding the degree
of thermal contraction, thereby substantially relieving
such negative pressure.
Yet another object is to provide fully airtight
and easily disposable liquid containers made of materials
such as thin aluminum, plastic or synthetic resins,
laminated paper, kraft paper, cup paper and the li~e,
which containers are defined by a tubular wall member and
by two cover or end-closure members at least one of which
end-closure members is adapted to relieve negative pres-
sure generated within the container.
-
1133837
_ --5--
!
1 These and other objects of the invention as well
~ as a fuller understanding of the advantages thereof can be
; had by reference to the following description, drawings
and claims.
Summary Of The Invention
The foregoing objects are achieved accordingto the present invention by the discovery of a novel
¦ 10 container for flowable materials including liquids such as
fruit juices and other non-carbonated beverages. Broadly,
the container comprises a tubular side-wall member her-
metically sealed at both ends, preferably with at least
one deformable end-closure described in greater detail
hereinbelow. The tubular side-wall member is preferably
cylindrical, i.e., having a circular cross-section.
Alternatively, the tubular wall member can have a poly-
gonal or elliptical cross-section.
According to one aspect of the invention, the
tubular wall member of the tubular container comprises a
tubular element composed of five plies bonded together,
preferably with an adhesive. For descriptive purposes
the plies can be visualized as being numbered from 1 to 5,
starting from the inner surface of the tubular element.
The first, third and fifth plies are each formed of an
elongated helically wound polymeric resin sheet material,
preferably polyolefin, e.g., polypropylene. The upper and
lower edges of the convolutions of each of the first,
third and fifth plies are overlapped with those of the
adjacent convolutions and the overlapped portions are
bonded to each other, preferably with an adhesive, to form
a tubular layer or ply. The second and fourth plies are
formed of a helically wound elongated cellulosic sheet
material, preferably cup paper, having abutted convolu-
`d
y
1~33B37
_ -6-
1 tions and which is desirably thicker than the polymeric
sheet material of the first, third and fifth plies. In
particular, the first, third and fifth plies each desirably
has a thickness of between about 0.08 and about 0.12 mm,
and preferably about 0.1 mm; and the second and fourth
plies each desirably has a thickness of between about 0.20
and about 0.30 mm, and preferably about 0.25 mm. Very
, good results are obtained with a container whose side-wall
! member has a total thickness of about 0.8 mm.
In another aspect of the invention, a tubular
container wall member is provided having a novel con-
figuration which permits the use of inexpensive kraft
paper liner sheet material as a substantial constituent of
the tubular element in applications where such material
, would otherwise be ineffective for preventing the odor of
the container's contents from permeating the container
wall and escaping or for preventing an offensive odor
from infiltrating the container contents from without. In
such circumstances, it would have been impossible prior to
the present invention to use an inexpensive kraft liner
paper which, although providing sufficient mechanical
strength, would tend to emit or impart to the container
contents an offensive odor. For this reason, the use of
cup paper sheet material has heretofore been mandatory.
In the present invention, the tubular wall member has a
bonded multilayer tubular element comprising, starting
from the inner wall surface, a first ply of polymeric
sheet material, preferably polyolefin; a second ply of
aluminum sheet material both sides of which are laminated
by thin paper; a third ply of kraft liner sheet material;
; and a fourth ply of polymeric sheet material, preferably
polyolefin. The third ply of kraft liner sheet is desir-
ably formed of a plurality of layers of such material,
- 35 preferably two layers. The various plies are preferably
bonded to each other, preferably with adhesive.
' -
1133837
--7--
1 The first, second and fourth plies of the
tubular element are preferably each formed of a helically
wound elongated sheet material having overlapping convolu-
tions, the overlapped portions of said convolutions being
bonded to each other, preferably with adhesive, to form a
tubular ply. Each layer of the second ply is formed of a
helically wound elongated sheet material, which is prefer-
ably thicker that each of the first, third and fourth
plies. Further, the edges of adjacent convolutions of
each layer of the second ply are in abutment rather than
I overlapped, to form a tubular layer. The first and second
i plies each desirably has a thickness of between about 0.08
i and 0.12 mm, and preferably about 0.1 mm; each of the
kraft liner paper sheets or layers constituting the third
ply has a thickness of between about 0.2 and about 0.4 mm,
and preferably about 0.3 mm, and the fourth ply has a
thickness of between about O.OS and about 0.1 mm, and
preferably about 0.07 mm.
~; 20 The container of the invention can be her-
metically sealed at one or both ends with a sealing or
closure member according to the present invention after
being charged with filler, e.g., a heated liquid. Such
closure is formed of rigid sheet material of sufficient
~ 25 flexibility and is provided with an outwardly bulged
j dish-shaped portion before sealing, whereby said bulged
portion is capable of undergoing inward deflection by
the negative pressure created in the container due to
thermal contraction of its contents. The dish-shaped
; 30 portion of the closure is desirably bulged to such an
outward extent that the volume by which the container is
reduced by inward deflection of said portion does not
- exceed the degree of thermal contraction, but rather
corresponds substantially to the thermal contraction of
the contents of the container or can, thereby substan-
.
1~33837
-- --8--
1 tially relieving such negative pressure. Suitablematerials for forming the end-closure include aluminum,
plastic, cup paper and the like, with aluminum sheet
material being especially preferred.
In reference to the above-described sealing or
j closure member, the bulged portion is formed in the
end-closure so as to be inwardly deflected in preference
to any deflection or deformation of the side wall by the
10 negative pressure generated in the container. Such
end-closure must therefore be designed to initially
withstand the negative pressure to a lesser degree than
the side wall of the container body. This requires the
end-closure to be thinner than would normally be the case
15 with more conventional non-deformable end-closures, and
; since the heat of the heated container contents tends to
lessen the strength of the container body, the end-closure
must also be thin enough to compensate for such reduction
in strength. On the other hand, a hermetic seal between
20 the end-closure and the container body is usually achieved
by folding their peripheries in a manner which is apparent
to those skilled in the container art. Accordingly, with
the thinner end-closure of the present invention it may be
somewhat difficult to obtain proper hermetic sealing of
25 the container. For instance, when the container wall is
~! of a composite structure made according to the present
invention of materials such as cup paper, laminated cup
paper sheet and the like and synthetic resin paper, it
is difficult to form a lap seam relying on plastic defor-
30 mation of such elements, since these materials, in con-
trast to metal, have neither malleability nor plasticity.
Consequently, the container body is sealed by the end-
closure in such a way that the metal end-closure material
is adapted to have its periphery folded to rigidly
35 hold the periphery of the container body. However, if
the end-closure is made thinner this not only weakens its
,
1133837
g
1 clamping force and makes it difficult to obtain a satis-
factory lap seam but also it requires specially designed
sealing apparatus other than those which are conventional
and desirable. For these reasons the end-cl~sure cannot
5 be thinned beyond a certain limit and in such cases it is
difficult to make an end-closure capable of being optimally
inwardly depressed in response to the negative pressure
created in the container. In such cases, the container
cannot relieve the negative pressure completely. Upon
10 consideration of the foregoing, it follows that aluminum
is preferred for use as the end-closure material; however,
aluminum is more expensive than the tinplates conven-
tionally used for container end-closures, thereby increas-
ing overall cost.
These potential problems are avoided in a
further aspect of the invention which provides a process
or method of canning goods in a sealable container and an
end-closure used for such purpose whereby the negative
20 pressure created in the container can be sufficiently
relieved and a bonding of the container body and the
end-closure is fully ensured. In particular, the ini-
tially outwardly bulged portion of the top end-closure is
inwardly depressed by a press or the like as opposed to
25 the previously described aspect of the invention wherein
the bulged portion is depressed by the negative pressure
created in the container. This avoids the necessity of
making the end-closure thinner and facilitates the forma-
tion of a hermetical lap seam between the open end of the
30 container and the flange of the end-closure. Further, the
sealing apparatus can be of conventional design thereby
reducing production cost, while the substantial inward
depression of the end-closure affords the desired avoid-
ance of any buildup in negative pressure. Furthermore,
35 the end-closure of this embodiment of the invention is not
~133837
--lo--
1 limited to the use of aluminum and the like, but rather,
can be formed of conventional tinplate blanks thereby
substantially reducing the cost (to about half as much as
aluminum) of manufacturing the end-closure.
Although this embodiment has been described
with reference to a container whose top end-closure is
provided with the bulged portion, it is not limited to
this particular construction. For example, the bulged
portion can be formed in the bottom end-closure and/or the
top-end closure.
i
In the case where only one end of the
container is fitted with the above-described sealing
closure, the other end can be fitted with any other
suitable conventional closure such as an easy-open top of
' the pilfer or pull-up tab type which are well-known
! in the beverage art. Such end-closure can be made of any
convenient material, e.g., aluminum, and is joined to the
container body before the latter is charged with filler.
In containers of the invention described
hereinabove where the volume of the contents is on the
order of 250 ml or less, the surface area of the pressure
responsive end-closure is sufficiently large relative to
the total surface area of the container that good results
are insured. ~owever, in the case of containers having
volumes as large as 500 ml, 1000 ml, or more, the use of a
single pressure responsive end-closure or even two such
end-closures may be insufficient to compensate for or
alleviate negative internal pressure to the degree desired.
This problem is solved according to another aspect of the
invention in the form of a tubular element which is itself
adapted to inhibit deformation of the sealed tubular
container of large as well as small volume in which a
i
33837
_"_
1 negative pressure is developed and which provides good
airtightness. In accordance with this aspect of the
present invention, the innermost ply or layer of the
tubular element of the tubular wall member is provided
with means adapted to be inflated inwardly in response to
~ negative pressure developed in the container, thereby
i decreasing the negative pressure so as to protect the
container wall from deformation, improve airtightness, and
preserve the shelf-life of the contents.
In particular, the tubular wall member of this
aspect of the invention has a bonded multilayer tubular
element comprising a plurality of plies, the innermost
ply being formed of a helically wound elongated polymer-
containing sheet material, preferably a polyolefin, havingoverlapping convolutions, the overlapped portions being
~; bonded, preferably~ with adhesive. The overlapped portion
of the convolutions of this innermost ply is provided with
a continuous bond along the seam and at least one addi-
20 tional and preferably continuous bond adjacent to and
substantially parallel with the first bond and defining
together with the first bond a slack portion therebetween
along the overlapped portion of the convolutions of the
innermost ply. The slack portion functions by virtue its
25 capacity to be taken up or inflated inwardly in response
to negative pressure in the container. Preferably, the
tubular element comprises three plies bonded together with
adhesive, the middle ply, i.e., the second ply from the
innermost ply, being formed of a helically wound elongated
; 30 cellulosic sheet material, preferably one or more layers
of kraft liner paper, which is thicker than either the
first or third ply. The edges of the adjacent convolut- O
- ions of the middle ply are in abutment to form a tubular
layer. The third or outermost ply is preferably formed of
35 a helically wound elongated cellulosic sheet material,
;:
.
~i
1133W7
- -12-
1 preferably kraft liner paper, having overlapping convolu-
tions, the overlapped portions of which are bonded to each
other, preferably by means of adhesive, to form a tubular
layer or ply. The first ply has a thickness of desirably
between about 0.08 and about 0.12 mm, and preferably about
0.1 mm. The second ply has a thickness of desirably
between about 0.2 and about 0.4 mm, and preferably about
0.3 mm.
Brief Description Of The Drawings
3 The present invention will now be further
r - described with reference to the accompanying drawings
~ wherein:
'~ 15
FIG. 1 is a side view of a conventional
foodstuff container shown in partial cross-section to
7 emphasize the details of its construction;
FIG. 2 is a side view in partial cross-section
of a beverage container having an end-closure and cylind-
rical wall member or element according to one embodiment
of the present invention;
FIG. 3 is a partial transverse cross-sectional
~ view of the cylindrical wall member of the container of
3 FIG. 2;
FIG. 4 is a representation of the structures of
the first, third, and fifth plies forming the cylindrical
wall member of the container of FIG. 2;
,. .
- FIG. 5 is a representation of the structures of
the second and fourth plies forming the cylindrical wall
member of the container of FIG. 2;
-
,
,~
1~33837
_ -13-
1 FIG. 6 is a fragmentary longitudinal cross-
section of the cylindrical wall member of the container
of FIG. 2;
FIG. 7 is a longitudinal cross-sectional view
of the top-end closure prior to being joined to the
cylindrical wall member of the container of FIG. 2;
~ FIG. 8 is a side view partially broken away of
¦ 10 a sealed cylindrical container according to a second
embodiment of the invention;
FIG. 9 is a longitudinal cross-sectional view of
a portion of the cylindrical wall member of the container
of FIG. 8;
~ FIG. 10.is a representation of the formation of
j the first, second and fourth plies forming the cylindrical
wall member of the container of FIG. 8;
FIG. 11A is a top plan view of one form of
an end-closure according to the present invention suitable
for use in forming the container of FIG. 8;
FIG. 1lB is an enlarged orthographic projection
of the end-closure depicted in FIG. 11A shown partially in
section;
FIG. 11C is an enlarged cross-sectional view of
a peripheral portion of the end-closure of FIG. 1lA;
FIG. 12A is an orthographic projection, partially
in section, of one form of a bottom end-closure suitable
for use with the cylindrical wall member and top end-closure
of the present invention in forming the container of FIG.
8; and
.
ii
~33837
_ -14-
1 FIG. 12B is a bottom plan view of the end-
closure depicted in FIG. 12A;
~ FIG. 13 is a side view, partially broken away,
i 5 of a sealed cylindrical container according to a third
embodiment of the invention;
FIG. 14 is a longitudinal cross-sectional view
of a portion of the cylindrical wall member of the con-
tainer of FIG. 13;
FIG. 15 is a side view, partially broken away,of the outermost layer of the cylindrical wall member of
the container of FIG. 13; and
FIG. 16 is a side view, partially broken away,
: of the second layer of the cylindrical wall member of the
container of FIG. 13.
Description Of Preferred Embodiments
The following examples are provided for the
purpose of illustrating, without limitation, the present
invention and the advantages thereof.
Example 1
Referring to FIG. 2, there is shown a container
12 according to the present invention for containing a
liquid, e.g., a beverage such as fruit juice. Container
12 includes top end-closure or cover 10 joined to the
upper edge or flange of cylindrical body member or element
14, and bottom end-closure or cover 15 joined to the
bottom edge or flange of the cylindrical body member.
3~
1133837
-15-
1 The container body 14 can be formed of any
suitable material such as aluminum, synthetic resin
or plastic, and cup paper insofar as they provide the
desired permeability and airtightness. In this embodi-
ment, container body 14 comprises a laminated composite
of five plies as shown in FIG. 3. The first, third, and
fifth plies 16, 18, and 20 are each composed of elongated
polymeric resin sheet material helically wound as shown in
FIG. 4. The second and fourth plies 22 and 24 are each
composed of elongated cup paper sheet material helically
wound between the adjacent plies 16, 18 and 20 as shown
in FIG. 5. The upper edge 28 and lower edge 30 of one
convolution 26B of each of the polymeric plies respec-
tively overlaps and is overlapped by adjacent convolutions
26A and 26C at their respective associated lower and upper
edges, the overlapped portions being bonded or glued to
each other by an adhesive therebetween to form a cylind-
rical layer. A preferred example of the polymeric resin
sheet material is sold commercially by Toyo Tafuper Co.,
Ltd. under the trademark "Tafuper" a polyolefin containing
much inorganic substance. An example of a suitable
adhesive for the overlapping portions of convolutions 26A,
2 and 26C is sold commercially by Gisuke Konishi & Co.,
Ltd. under the trademark "KU-820". As shown in FIG. 5,
the second and fourth plies 22 and 24 are helically wound;
however, convolution 32B of each ply is butted at its
upper and lower edges to adjacent convolutions 32A and 32C
instead of bein~ overlapped.
In the manufacture of container body 14, de-
picted in its various parts in FIGS. 2 through 6, the
sheet for first ply 16 is initially wrapped about a
cylindrical mandrel (not shown) of a desired diameter.
Next, sheets for the second, third, fourth, and fifth
plies 22, 18, 24 and 20 are successively wrapped around
-
,
1133837
_ -16-
1 the mandrel, preferably in the same direction, to form
an elongated cylindrical member. The convolutions of the
wound sheets are overlapped or butted, as the case may be,
and the sheets are joined to each other by a suitable
adhesive, e.g., of the type sold by Koatsu Gas Kogyo Co.,
Ltd. under the trademark "Pegarl 210P". This cylindrical
member is then cut to a desired length to obtain container
body 14.
The first, third, and fifth plies 16, 18, and
20 impart the requisite airtightness to container body
-
14 while effectively containing any odor emanating from
the cup paper used for the second and fourth plies 22 and
24. The second and fourth plies 22 and 24 impart adequate
_
mechanical strength to cylindrical body element 14.
The sheets of polymeric resin and cup paper
can be employed in various thicknesses consistent with
the foregoing disclosure. In the present preferred
embodiment, the sheet material used for the first, third
and fifth plies 16, 1~, and 20 is about 0.1mm thick, and
the sheet material used for the second and fourth plies 22
and 24 is about 0.25mm thick. The average total thickness
of all the plies of container body 14 is about 0.8 mm.
A double seam 41 is formed as shown in FIG. 2 in order
. to provide airtightness between container body 14 and
i top end-closure 10 and likewise between the container body
and bottom end-closure 15. It has been found, how-
ever, that such double seams become increasingly difficult
to form if the container body 14 is substantially thicker
than about 0.8 mm. On the other hand, if the container
body is substantially thinner than about 0.~ mm, it tends
to have less than desired strength. The bottom end-
closure 15 is conventional and can take the form of an
easy-open end such as a pilfer or pull-up taù well-known
113383'7
_ -17-
1 in the beverage packaging art. The bottom end-closure 15
in this instance is made of aluminum and is joined to
container body 14 before the container 12 is filled.
Incidentally, it should be noted that the terms "top-end
closure" and "bottom end-closure" are used herein with
reference to the drawings; in the context of actual use of
the container in the upright position, the "bottom end-
closure" would normally become the top and vice versa.
The top-end closure _ is formed with the con-
figuration shown in FIG. 7, and has an initially convex or
dish-shaped bulge portion 42, an inclined side 40, an an-
nular shoulder _ adapted to be fitted into the interior of
container body 14, and a flange 38 which is adapted to be
double-seamed by conventional means (not shown) to the
upper flange of the container body. Top end-closure 10 is
hermetically joined to the upper edge of the container
body immediately after the filler, e.g., fruit juice which
has been heated to a predetermined temperature (normally
at least about 90C), has been charged to the container
body and bottom-end closure assembly. After being fully
sealed, the beverage-filled container is allowed to stand
at ambient temperature or is placed in a refrigerator.
In such circumstances the pressure of the fluid within
¦ 25 the container decreases, thereby producing a negative
I pressure. As a result, the dish-shaped bulge 42 is in-
} wardly deflected or "popped" to form a concavity or "dent"
; in top-end closure 10 as shown in FIG. 2. The extent to
which the volume of container 12 is thereby reduced is
30 defined by the disc-shaped bulge 42 shown by the dotted
line and the concavity shown by the solid line in FIG. 2,
r and is enough to compensate for the thermal contraction of ~
- the filler, thereby substantially relieving the negative
pressure in the container. It is, of course, desirable to
35 that top end-closure 10 be formed in such a manner that
-
7~
~1338~7
_ - -18-
1 the degree to which the volume of the can is reduced by
inward deflection of bulge 42 corresponds to the degree of
thermal contraction of the contents in the can so that the
negative pressure is essentially reduced to zero, i.e.,
neutralized. However, if desired, top-end closure 10 can
be dimensioned so that some negative pressure is left in
container 12 after the dent is formed in bulge 42 so long
as it does not affect the strength or airtightness of the
container. Very good ~esults are obtained by forming the
above-descr~bed end-closure from H-24 0.20 MT aluminum
sheet material sold by Kito Sangyo and Shibazeki Susakasgo
Co. under the name "Flexiendn.
Example 2
Referring to FIG. 8, a sealed fruit juice con-
tainer _ is formed py applying top-end closure 54 and
bottom end-closure 56 to the upper and lower edges of
cylindrical container body 52.
As is apparent from the longitudinal cross-
section depicted in FIG. 9, cylindrical member 52 is
composed of a plurality of plies. Specifically, cylind-
rical member 52 comprises, starting from the inside
(right-hana of FI~. 9), layer 58 (first ply) of polyolefin ~ -
resin sheet material; aluminum sheet layer 60 (second ply)
both sides of which are laminated with thin paper sheets
61 and 63; ~raft liner paper sheet layer 68 (third ply)
having respPctively inner and outer layers 62 and 64 of
1 30 kraft liner paper, and a further layer 66 (fourth ply) of
j polyolefin resin sheet material. Although the container
body is pre~erably formed using aluminum as the second ply
60, the present invention can also be applied to tinplate,
particularly thinner tinplates than those conventionally
used, there~y effecting substantial cost savings.
.
. ~ * Trade Mar~
:, .
.
~133837
_19_
1 The first, second and fourth plies 58, 60, and
66 shown in FIG. 9 are helically wound as shown in FIGS. 8
and 10. The upper edge 70 of one convolution overlaps the
lower edge 72 of the adjacent convolution and the thus-
overlapped portions of the convolutions are bonded together
to form a cylindrical ply. The inner layer 62 and the
outer layer 64 of the third ply 68 are, as apparent from
FIG. 9, respectively made by spirally winding an elongated
sheet of kraft liner paper without overlapping, but
rather, by abutting the edges of the convolutions.
The first, second, third and fourth plies 58, 60, 68 and
66 and the inner and outer layers 62 and 64 of the third
ply are bonded to each other, preferably by adhesive.
In practice, container body 52 is formed by
wrapping or winding the sheet for the first ply about a
mandrel (not shown) of a desired diameter. Next the
sheets for the second, third (inner and outer layers), and
fourth plies are successively wrapped or wound about the
mandrel to form an elongated cylindrical member. The
convolutions of the sheets are overlapped or abutted, as
the case may be, and the sheets are joined to each other
by application of an adhesive between successive windings.
The thus-formed cylindrical member is then cut to a
desired length to obtain container body 52.
The first ply 58 of polyolefin resin serves to
fully prevent the fruit juice from permeating the wall of
the container, although an acceptable loss through absorp-
tion by the first ply of some product aroma may be in-
evitable. The second ply 60 of aluminum laminated by thin
paper sheets 61 and 63, serves to fully prevent the aroma
of the fruit juice from escaping further. The kraft liner
paper of the third ply 68 (both inner and outer layers 62
and 64 are not mandatory; either a single layer or a
~133837
_ -20-
1 multiplicity of layers can be used) provides sufficient
strength ~o resist internal - external pressure dif-
ferences ~nd corresponding tensile or compressive forces
in the axial direction. In this connection, it has been
found tha~, although kraft liner paper has more strength
than the ~up paper used in the embodiment of Example ~ and
FIGS. 1-7~ it is somewhat less desirable due to its
odor. Ac~ording to the present embodiment, aluminum sheet
layer 60 ïs employed as the second ply to inhibit any
offensiv~ odor of kraft liner paper from infiltrating the
contents ~f the container so that such paper can be
advantag~usly used as the third ply. Finally, polyolefin
resin sh~t layer 66 is applied as the fourth ply out-
wardly o~ the kraft liner paper 68 to fully prevent
moisture ~ntering from without.
The materials listed below are especially
suitable ~or use as the first, second, third, and fourth
plies for container body 52 of container 50 of FIGS.-8
through ID. The container 50 typicaliy has an outer
diameter Df 56 mm, a height of 137 mm, and a side-wall
thicknes~ of 0.87 mm, an arrangement which has been found
to be particularly satisfactory for pac~aging fruit
juices.
First ply: "Tafupern, -FR 0.1 mm-, -
manufactured by Toyo Tafuper
Co., Ltd.;
Second ply: "Thin paper laminate aluminum
sheet n ~ -35 g, 0.1 mm-, manu-
factured by Mitsu~ishi-Aluminum
Co., Ltd.;
Third ply: "Kraft liner paper" ("K-Liner") -~
-A 220 g, 0.3 mm - manufactured by
Tohoku Paper Mills Co., Ltd.
(~oth layers); and
* Trac- Mark
~133837
- -21-
1 Fourth ply: ~Tafupern, - OMT 0.G7 mm-,
manufactured by Toyo Tafuper
Co., Ltd.
Incidentally, the material "Tafuper (OMT) n
used as the fourth ply is characterized in that it accepts
conventional printing materials directly on its surface
and therefore can be conveniently used as the outermost
layer.
'10
The following adhesives are especially suitable
for bonding adjacent plies to one another and for bonding
the overlapped portions of the convolutions of the first,
second and fourth plies:
"Tafuper" to "Tafuper": "KU-82~" manufactured
by Gisuke Konishi & Co., Ltd.
"Tafuper" to laminate aluminum; kraft liner
paper to nTafuper": "G 6000" manufactured by Gisuke
Konoshi & Co., Ltd.
- Laminate aluminum to kraft liner paper; kraft
liner paper to kraft liner paper: "Pegarl 210P"
manufactured by Koatsu Gas Kogyo Co., Ltd.
~eferring to FIGS. 11A, 11B and 11C, end-closure
54 has a convexity or bulge portion 74 formed in the
center. Bulge portion 74 is adapted to be inward~y
deflected to reduce the volume of the container and
thereby increase (i.e., relieve) the internal negative
pressure which results, e.g., when the temperature of
the sealed contents decreases. In this way, compressive
stress generated on the cylindrical wall member of the con-
tainer is reduced. For Pxample, when bulge portion 74 -~
is about 3.~ cm3, the volume of the sealed container
will be reduced by about 7 cm through inward deflection.
These parameters have been found to work very well for an
* Trade Mark
1~338~7
_ -22-
1 end-closure 54 having an outside diameter of 52.0 mm and a
bulge portion 74 having a diameter of 24 mm.
Referring now to FIGS. 12A and 12B, bottom
end-closure 56 is provided with a conventional so-called
"pull-top" which is opened by outwardly pulling tab
76 to tear off a portion of the closure defined by line
78 so that the flowable contents of the container such as
fruit juice can be poured or drunk from the resulting
opening. A suitable pull-top end-closure is manufactured
and sold by Hokkai Seikan. An accelerated stability test
establishes that liquids such as fruit juice can be stored
and preserved in the sealed container formed according to
the present invention for at least seven months without
deterioration. After use the container can readily be
disposed of, since the polyolefin resin sheet material,
typically "Tafuper" and the kraft liner paper will burn at
about 700 - 720C with liberation of 5000 - 7000 calories
per gram without generating noxious gas and excessive
2Q smoke.
Example 3
Referring to FIG. 13, a sealed fruit juice
container 80 is formed by applying top end-closure 84
and bottom end-closure 85 to the upper and lower edges
respectively of cylindrical tubular container body 80.
As is apparent from the partial cross-sectional
view in FIG. 14, cylindrical body 82 consists of four
layers or plies. Outermost layer 88 is, as shown in FIG.
t5, made by spirally winding an elongated sheet of water-
proof paper, the upper and lower edges of each convolution
90 overlapping and being overlapped by the edges of the
adjacent upper and lower convolutions, respectively, the
1~33837
_ -23-
1 overlapped edges being glued or otherwise bonded to each
other to form a cylindrical layer. A suitable water-proof
paper for use in forming outermost layer 88 is sold by
Unichica Co. Ltd. under the name "UP0". Second layer 86
and third layer 87 are each made as shown in FIG. 16 by
spirally winding an elongated sheet of kraft liner paper
of relatively greater thickness than outer layer 88, the
edges of each convolution being in abutment to each other
to form a cylindrical layer. Innermost layer 94 is also
made by spirally winding an elongated sheet of polymeric
resin and overlapping the edges 96 of each convolution
with those of the adjacent convolutions in a manner
similar to outermost layer 88; here, however, the attach-
ment of overlapped edges 96 is effected in the manner
shown in FIG. 14; that is, along the overlapped edge
portions, there are provided two continuous elongated
welds or bonds 98 and 100 which are spaced apart from each
other. Between the welds some slack 104 is left. Th-ese
welds can be formed by heat-welding, supersonic welding,
and the like and the above four layers or plies are bonded
to each other in the manner described above. In a pre-
ferred embodiment, the bond between the polymeric resin
sheet of innermost layer 94 and the kraft liner paper of
third layer 87 is advantageously strengthened by the
25 application of corona discharge to the polymeric resin ;
sheet to form a roughness on the surface thereof prior to
bonding.
Innermost layer 94 serves to prevent liquid
material-from permeating the container and to provide
airtightness. For this purpose, "Fresckfilmn sold by
Takigawa Chemical Kogyo Co., Ltd. is used as the mate-
rial of innermost layer 94 and has been found tv be
particularly satisfactory. "Fresckfilm" consists
of ~he following four layers: polyethylene (about
* Trade Mark
113383~7
_ -24-
1 40 microns !, polyester (about 12 microns), evaporated
aluminum (less than several microns), nylon (about 15
microns) and polyethylene (about 40 microns).
The kraft liner paper of the second and third
layers 86 and 87 provides mechanical strength to
container body 80. In the embodiment illustrated in
FIG. 14, the second and third layers are made of kraft
liner paper "A 220 g, 0.3 mm" manufactured by Tohoku Paper
Mills Co., Ltd. Insofar as achieving the necessary
mechanical strength to resist internal pressure and
resulting compressive forces in the axial direction is
concerned, it is possible to use a single layer of kraft
liner paper in place of the two layers illustrated in this
example.
Conventional closure means, e.g., aluminum
covers, can be used as the upper and lower end-closures
84 and 86 in conjunction with the container body member
82 of this embodiment; however, in large volume containers
in which substantially greater negative pressures are
developed, it is preferable to use at least one end-
closure of the present invention described hereinabove as
a closure means. The bottom, conventional end-closure is
advantageously provided with opening means such as the
so-called pull-top described hereinabove. Even if nega-
tive internal pressure develops after container 80
equipped with conventional end-closures is sealed, the
slack 104 in innermost layer 94 is taken up inwardly in
response to the negative pressure, thereby substantially
lowering or relieving the negative pressure.
Incidentally, although in the present embodi-
ment, the overlapped portion of the innermost layer is
provided with two welds or bonds 98 and 100, three or more
~33837
-25-
1 welds can be formed so as to form any desired number of
slacks 104. Furthermore, both of the welds or bonds 98
and 100 are formed continuously along the overlapped
portion of innermost layer 94; however since the airtight-
5 ness of the layer is maintained by the first continuousweld, the second weld need not necessarily be formed
continuously as long as some slack in the inner sheet is
left between the first and second welds. Furthermore,
although innermost layer 94 illustrated above is formed by
10 spirally winding an elongated sheet, it is not limited as
such; for example, it can be formed by making a wide width
sheet into a circle to form a cylindrical layer. Further-
more, the tubular container bodies of this invention
are not limited to those having a cylindrical (circular
5 cross-section) configuration, but rather, can be formed,
e.g., with a polygonal, elliptical or other non-circular
cross-section.
xample 4
~ eferring again to FIGS. 2 and 7 a further
embodiment of the invention will be described in which
container 12 is manufactured according to a method of the
invention.
~ he container 12 can be manufactured by the
steps of heating and charging a beverage such as fruit
juice in container body 14 in the form of cylindrical
container, to which a bottom end-closure 15 has been
3~ joined, and joining a top end-closure 10 formed of desired
material such as tinplate to the upper end of the body
member. The top end-closure 10 is formed into a dish
shape as shown and is provided substantially centrally
thereof with an outwardly bulged portion 42 before being
35 joined to the container body.
1~33Y 37
-26-
1 After covering container body 14 with the top
end-closure 10, flange 38 of the top end-closure and the
upper end of the container body are overlapped and then
folded to form a so-called "double-seam" 41 by means of a
5 sealer or sealing apparatus (not shown) whereby the
container is closed and sealed.
Next, the initially outwardly bulged portion
42 of the top end-closure 10 is urged by a press (not
10 shown) toward the interior of the container body, thereby
reversing the bulge and inwardly deflecting or "popping"
it to form a concavity as shown in FIG. 2. This pressing
step should be performed prior to lowering the temperature
of the contents in the container otherwise the drop in
5 temperature and consequent thermal contraction of air
within the container will create an unrelieved nega-
tive pressure which tends to inwardly deform the wall of
the container. Preferably, the top-end closure bulges
outwardly to such an extent that reduction in volume of
20 the container will be approximately equal to the volume of
the thermal contraction of the container contents.
Industrial Applicability
As described above, the present invention pro-
vides a composite container for liquids which can function
fully as a su~stitute for conventional containers made of
glass, tinplate and the like. It also provides a closure
member for hermetically sealing a container after it has
30 been fi~led with a heated beverage and is characterized by
a dish-shaped portion which is outwardly bulged before
sealing and which undergoes inward deflection by the
negative pressure created by thermal contraction in the
container after sealing and upon cooling. In this way,
35 the negative pressure in the container is substantially
~133837
_ -27-
1 relieved so that the container can be made of inexpensive
materials with lesser rigidity than would be otherwise
necessary, such as plastics, cup paper and the like,
instead of the tinplate now widely used. It is a feature
of the invention that, even if the container is formed of
cup paper or the like, it is possible to store it at room
temperature for extended periods since differences
in pressure between the exterior and interior of the can
will not prejudice airtightness and imperviousness to
microorganisms. A further advantage is that the container
can be made of materials which can be readily disposed of
e.g., by burning.
