Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
This invention relates to the art of collapsible dis-
pensing containers and, more particularly, to a laminated
tube structure for the body of such a container and a method
of making the tube.
Collapsible tubular containers are prov~ded for dispensing
a wide variety of products including, ~or example, cosmetics,
shampoos, foods, dentifrices and the like. Problems encountered
in connection with oxygen absorption and product contamination
and permeation have led to considerable ef~orts to provide
laminated constructions for the body po~tions of the dispensing
containers to overcome the problems. Such laminated construc-
tions generally include a barrier layer of metal foil to elimi-
nate oxygen absorption and water vapor transmission and inner
and outer layers of a thermoplastic material such as polyethylene.
The inner layer of polyethylene protects the product from con-
tamination by the metal foil but, while such inner layer can be
made relatively thin, an undesirable degree of product permeation
still takes place causing deterioration of the product ~n the
~ container. Heretofore, the tubular body portions of such con-
tainers have been produced by forming a flat laminate into
tubular form with overlapping edges and then heat sealing the
edges to provide a tube having a longitudinal ~eam. Such a
heat sealed construction necessitates heat sealing compatibility
of the inner and outer layers of the laminate and thus requires
both layers to be thermoplastic. Accordingly, such previous
methods of cor,struction limit selectivity of materials and thus
limit the use of containers employing such body constructions.
Moreover, the compatibility requirements for heat sealing have
made it impossible to employ thermosetting plastic materials
for the inner surface of the tubular body so as to minimize
the product permeation ~roblem for the inner layer of a container.
With further regard to such previous container body con-
structions, the longitudinal seam produced by heat sealing the
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laminate edges creates problems with respect to providing indicia
on the outer surface of the tubular body. In this respect, such
a longitudinal seam makes it necessary to pre~print the plastic
film defining the outer layer of the laminate by rotogravure
printing methods. More particularly, the presence of a longi-
tudinal heat sealed seam in the tubular body portion provides
an interruption in the otherwise circular outer surface contour
of the tube, whereby the tube cannot be printed upon after for-
mation thereof by less expensive techniques such as roll print-
ing. Still further, such a longitudinal heat sealed seam isvisible and, accordingly, is undesirable from the standpoint of
aesthetics.
Definitions .
Mechanical bond, or mechanically bonded, as used herein
means a bond in which two films or layers of material are ad-
hered to one another such that they can be peeled apart.
Thermal bond, or thermally bonded, as used herein means
a bond in which two films or Iayers of material are fused or
otherwise adhered to one another such that they cannot be peeled
apart without rupturing or tearing one of the films, or layers.
Heat sealed, or heat sealing, as used herein means a
thermal bond.
Bond, or bonded, as used herein without reference to
either a mechanical or a thermal bond means a bond in which
two films or layers of material are adhered either by a mechan-
ical bond or by a thermal bond.
Sum~ary of the Invention
The disadvantages of collapsible dispensing container
bodies heretofore provided, and the disadvantages of the methods
of construction thereof are minimized or overcome in accordance
with the present invention. In this respect, the present in-
vention enables the production of a tubular dispensing-container
body having an inner surface which is less permeable than those
of laminated structures heretofore provided, enables the pro-
duction of a collapsible container body having an outer surfaceuninterrupted by a longitudinal heat sealed seam, and enables
the use of a wide variety of materials in producing a tubular
dispensing container body by avoiding the necessity for compatible
thermoplastic materials to enable heat sealing. In accordance
with one aspect of the present in~ention, the inner surface of
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a laminated tube for use as a collapsible container body is
defined by a thermosetting plastic material which, preferably,
is an epoxy resin. In accordance with another aspect of the
invention, a laminated tube for use as a dispensing container
body includes a tubular core having circumferentially over-
lapping marginal side edges, the core being enclosed in a
seamless sheath of plastic material in a manner which provides
structural integrity for the longitudinal seam without the
presence of a heat sealed seam along the tube.
In accordance with a preferred embodiment of the invention,
a dispensing container body tube is produced by forming a sheet
or laminate of core material into a tubular configuration having
circumferentially overlapping marginal-side edges and then en-
capsulating the tubular core in a seamless sheath of flowable
plastic material, such as by extrusion of the plastic about
the core. This advantageously enables the use of thermally
incompatible materials for the inner and outer layers of the
tube, and enables the use of a thermosetting plastic for the
inner layer of the tube- In this respect, the plastic sheath
is bonded to the core and thus maintains the core in tubular
form, advantageously avoiding the necessity for a heat sealing
compatibility between the material of the sheath and a layer of
the core defining the inner surface of the tube. Additionally,
by avoiding a heat sealed seam the tube can be roll printed after
it is produced.
Further, in accordance with a preferred embodiment of the
invention, the overlapped marginal side edges of the core are
interlocked with the sheath material in a manner which optimizes
the structural integrity of the seam when the core is encapsulated
and stabilizes the radially inner one of the marginal side edges
against displacement inwardly of the tubular body. Such an
interlocked relationship preferably is achieved by providing
a thin bead of the sheath material along and about the longi-
tudinal edge of the radially inner one of the overlapped marginal
side edges prior to extrusion of the sheath material about the
core. During the extrusion operation the material of the
bead fuses and becomes integral with the material of the
; extruded sheath. The heating of the bead material during
the extrusion process provides for the overlapped marginal
4~ edges to be mechanically bonded to one another by the interposed
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layer of the bead material, and fusing of the bead material
with the sheath provides continuity of the sheath material be-
tween the overlapped marginal edges and about the longitudinal
side edge of the radially inner one of the marginal edges. This
mechanical bonding is sufficient to prevent displacement of the
radially inner one of the overlapped marginal edges inwardly of
the tubular b~dy relative to the outer one of the edges and which
displacement would leave only the sheath material along the longi-
tudinal seam to hold the core in tubular form. Additionally, the
continuity of the sheath material about the side edge of the
radially inner one of the marginal edges, locks the overlapped
edges against circumferential displacement in the direction
of overlap. Thus the structural integrity of the seam is opti-
mized and, if the core includes a barrier layer of metal foil,
the bead advantageously covers the otherwise exposed edge thereof
along the seam.
It is accordingly an outstanding object of the present in-
vention to pro~ide an improved laminated tube construction for
use as a body of a collapsible dispensing container.
Another object is the provision of a laminated tube con-
struction of the foregoing character having an inner surface
which provides improved resistance to product permeation.
Yet another object is the provision of a laminated tube
construction of the foregoing character having inner and outer
layers of thermally incompatible plastic materials.
Still another object is the provision of a laminated tube
construction of the foregoing character which is free of any
heat sealed seams.
A further object is the provision of a laminated tube con-
struction of the foregoing character having an inner layer ofthermosetting plastic material, a barrier layer and an outer
layer of plastic material.
Still a further object is the provision of a laminated tube
construction of the foregoing character including a tubular core
having longitudinally extending circumferentially overlapped
marginal side edges encased in a seamless sheath of plastic
material in a manner whereby the marginal side edges are inter-
locked with the sheath material against relative circumferential
displacement of the overlapped edges and radially inward displace-
ment of the inner one of the marginal side edges.
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Yet a further object is the provision of a laminatedtube construction of the foregoing character which includes a
tubular core laminate of metal foil and thermosetting plastic
encapsulated in a seamless sheath of plastic material.
Another object is the provision of an improved method
for making a laminated tube for use as the body portion of a
collapsible dispensing container.
Yet another object is the provision of a method of the
foregoing character which enables a wider selectivity with res-
pect to plastic materials included in the layers of the laminatedtube.
Still another object is the provision of a method of
the foregoing character which enables the tube to have an outer
surface free of any visible longitudinal seams.
A further object is the provision of a method of the
foregoing character which enables the tube to have inner and
outer layers of plastic material which are incompatible for heat
sealing.
Yet a further object is the provision of a method of
,20 the foregoing character which enables overlapping edges of a
tubular core of the laminated tube to be interlocked with the
material of a sheath enclosing the core in a manner which
optimizes structural integrity of the longitudinal seam of the
completed tube.
In accordance with one broad aspect, the present inven-
tion relates to a laminated tube having radially inner and outer
surfaces and adapted to be used as the body of a collapsible dis-
pensing container comprising, a tubular core including a layer
of material providing said inner surface of said tube, said core
having longitudinally extending circumferentially overlapped
marginal side edges including said layer of material and terminat-
ing in circumferentially opposite directions, and a seamless
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sheath of plastic material surrounding and bonded to said core
and providing said outer surface of said tube, said plastic
material of said sheath being thermally incompatible with said
core layer providing said inner surface of said tube.
In accordance with another aspect, the present inven-
tion relates to a method of making a seamless laminated tube
adapted to be used as the body of a collapsible disp~nsing con-
tainer comprising, forming a sheet of core material to a tubular
configuration having longitudinally extending circumferentially
overlapping marginal side edges, said core material having
thermally incompatible radially inner and outer surfaces in said
tubular configuration, and encapsulating said tubular core in a
seamless sheath of plastic thermally incompatible with the core
material providing said radially inner surface, and curing said
plastic material.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing objects, and others, will in part be
obvious and in part pointed out more fully hereinafter in con-
junction with the written description of preferred embodiments
of the invention shown in the accompanying drawings in which:
FIGURE 1 is a perspective view of a core laminate for
a laminated tube constructed in accordance with the present
invention;
FIGURE 2 is a cross-sectional view showing the core
laminate when initially fGrmed into a tube;
FIGURE 3 is a cross-sectional view showing the core
just prior to extrusion of the sheath material thereabout;
FIGURE 4 is a cross-sectional view showing the
completed tube, and,
FIGURE 5 is a plan view schematically illustrating
apparatus by which a laminated tube is made in accordance with
the present invention.
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Description of Preferred Embodiments
Referring now in greater detail to the drawings wherein
the showings are for the purpose of illustrating preferred em-
bodiments of the invention only and not for the purpose of
limiting the invention, FIGURE 1 illustrates a core laminate
10 comprised of a barrier layer 12 preferably of metallic foil
and a layer of thermosetting plastic material 14 suitably bonded
to one side of the barrier layer. Laminate 10 has longitudinally
extending opposite marginal side edges 16 and 18 and, as set
forth more fully hereinafter, marginal edge 16 is provided with
a thin bead or film of plastic material 20 after which the
laminate is formed about a mandrel 22 to a tubular configuration
as shown in FIGURE 2. More particularly, it will be seen that
film 20 is longitudinally coextensive with marginal edge 16
lS and includes a portion 20a extending laterally inwardly over
barrier layer 12, a portion 20b extending laterally inwardly
over thermosetting plastic layer 14, and a portion 20c extend-
ing across the vertical side edge of the laminate. When core
laminate 10 is formed to the tubular configuration, marginal
side edges 16 and 18 are disposed in circumferentially over-
lapping relationship with thermosetting plastic layer 14 dis-
posed inwardly of the tube Accordingly, marginal edge 16
becomes the radially inner one of the overlapped edges, and
portion 20a of film 20 is disposed between marginal edges 16
and 18 and more particularly between the.foil of marginal
edge 16 and the thermosetting plastic of marginal edge 18.
As seen in FIGURE 3, overlapping edges 16 and 18 are then
displaced radially against a flat 24 on mandrel 22, As ex-
plained hereinafter, this enhances achieving a more uniform
radial thickness of the sheath material in which the core is
subsequently encapsulated, As seen in ~IGURE 4, the tubular
core is then encapsulated in a seamless sheath of plastic
material 26 which is bonded to the outer surface of barrier
layer 12 so as to maintain the core in tubulàr form. Film 20
and sheath material 26 are of the same plastic material and
during encapsulation, portion 20a of film 20 fuses with and
becomes integral with sheath material 26. Film portion 20a
mechanically bonds with the thermosetting plastic on marginal
edge 18 to hold marginal edge 16 against displacement radially
inwardly of the encapsulated core relative to marginal edge 18.
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This advantageously avoids a longitudinal line of potential
weakness which would result from such displacement of marginal
edge 16 in that the tube seam would then be defined only by
the thickness of the sheath material in area 26a thereof.
Further, the fusing of sheath material 26 with bead portion
20a provides a thermal bond therebetween, whereby bead 20
becomes an integral extension of the sheath which locks
around the longitudinal inner edge of the core and thus ad-
vantageously resists any relative circumferential displacement
of marginal edges 16 and 18 in the direction of overlap thereof.
Thus, overlapped edges 16 and 18 are stabilized by the mechanical
bond and the locking relationship, and the structural integrity
of the longitudinal seam along the co~pleted container body is
optimized.
Encapsulation enables the outer surface 28 of the tube to
be circular ;n cross-sectional contour and free of any longi-
tudinal seams. Moreover, encapsulation avoids the necessity
for heat sealing compatibility between the plastic materials of
inner and outer layers 14 and 26 of the tube as is required to
achieve a thermally bonded seam in tube constructions hereto-
fore provided. At the same time, it will be appreciated that
the materials of the inner and outer layers can be compatible
if desired. Thus, inner and outer layers 14 and 26 in the
embodiment described can be like or different thermosetting
materials, or a combination of a thermosetting inner layer and
a thermoplastic outer layer. Ther~fore, it will be appreci-
ated that the inner and outer layers can be selected from a
wide variety of materials depending on the particular product
to be stored and dispensed from a collapsible container having a
body portion made from the tube.
In the preferred embodiment, the thermosetting material
of inner layer 14 is a high temperature setting epoxy resin,
and outer layer 26 is a thermoplastic material, preferably a
low density polyethylene. Barrier layer 12 is aluminum foil
having a thickness of about 0.002 inch. Epoxy layer L4 has
a thickness of about 0.0005 inch, a suitable epoxy resin being
that sold by Hanna Chemical Company of Columbus, Ohio unde_
product designation H-ll or H-23, which has a curing tempera-
ture of about 550F and a curing time of about eight minutes.
Polyethylene layer 26 has a thickness of about 0.003 inch and,
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with regard thereto, it will be appreciated that the thickness
in the area 26a thereof will vary from the latter dimension.
Bead 20 is also polyethylene, and portions 20a, 20b and 20c
thereof each have a thickness of about 0.003 inch. Further,
marginal edges 16 and 1~ have a circumferential overlap of
about 0.090 inch and bead portions 20a and 20b have a lateral
width corresponding to the dimension of overlap.
The laminated tube is preferably produced continuously,
and the tubular core is preferably encapsulated in sheath 26 by
extruding the sheath thereabout. FIGURE 5 of the drawing schema-
tically illustrates production of the tube in this manner. In
this respect, a roll 30 of the laminated core material 10 is
supported at one end of the forming apparatus to provide an
indeterminate length of the core material. The forming
apparatus includes circular mandrel 22 referred to hereinabove
and which has an upstream end 22a thereof attached by welding
or the like to a rigid support member 32. Mandrel 22 extends
the full length of the apparatus and has a downstream terminal
end 22b. Core material 10 is continuously fed from roll 30 to a
forming plow 34 which, in a well known manner, operates to
bend material 10 into tubular form about mandrel 22 as the
core material moves through the plow. Bead 20 is applied in
the form of molten thermoplastic material to edge 16 of the
core material upstream from plow 34. The bead can for ex-
ample be applied by means of a pump P having a nozzle struc-
tured and positioned to apply the bead as shown in FIGURE 1.
The plastic material of bead 20 can be supplied to pump P
from any suitable source and, for example, can be supplied
from the source of molten plastic for the sheath extruder
referred to hereinafter.
It will be appreciated that plow 34 and mandrel 22 co-
operate to form core material 10 substantially to the tubular
configuration shown in FIGURE 2 of the drawing. By the time
bead 20 engages the mandrel surface it has cooled sufficiently
to avoid any problems of adherence of bead portion 20b there-
with. The tubular core material then passes along mandrel 2~
through a sizing ring device 36 which, as is well known, serves
to bring the tubular core to a desired cross-sectional dimen-
sion. Depending on the materials of the core laminate, it may
be desirable to warm the material to enhance the sizing operation
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and, for this purpose, sizing member 36 preferably includes a
circumferentially closed housing having inlet and outlet pass-
ages 38 and 40 for circulating hot air therethrough. From
sizing member 36, the tubular core passes along mandrel 22
through an extrusion cross head die 42 by which outer layer 26
of plastic material is extruded onto the exterior surface of
the tubular core. Preferably, to obtain a generally uniform
radial thickness of extruded layer 26, roller R is provided at
the entrance end of extrusion die 42 in cooperable relationship
with flat 24 on mandrel 22 to form the radial step in overlapped
marginal ~ide edges 16 and 18 of laminate 10 as shown in FIGURE 3.
The material extruded onto the tubular core can either be
a thermoplastic or thermosetting plastic material and is fed to
cross head die 42 through an inlet 44 leading from a plastic
extruder, not shown. As mentioned hereinabove, pump P for
applying head 20 to the core material can also be connected
to the extruder to receive the molten plastic for the bead there-
from. In the preferred embodiment, outer layer 26 is a thermo-
plastic material and, accordingly, the sheathed tube exiting
from cross head die 42 passes through a cooling jacket 46 to
at least partially cure the extruded plastic layer. For this
purpose, it will be appreciated that jacket 46 is provided with
inlet and outlet passages 48 and 50, respectively, to facilitate
the circulation of a suitable cooling medium therethrough. It
will be further appreciated of course that a heating jacket
would be employed if layer 26 was a thermosetting plastic. A
suitable drive arrangement such as endless belts 52 and 54 is
provided adjacent the outlet of cooling Jacket 46 to facilitate
driving the completed tube from the downstream end 22b of
mandrel 22, and it will be appreciated that a suitable cut-off
mechanism, not shown, is preferably provided beyond the down-
stream end of the mandrel to cut the finished tube into desired
lengths.
While the preferred tube structure has an inner layer of
a thermosetting plastic material, a layer of metal foil to which
the thermosetting plastic layer is bonded and an outer layer of
plastic bonded to the metal foil and providing the outer surface
of the tube, it will be appreciated that layers of material
could be interposed between the thermosetting plastic inner
layer and metal foil and between the metal foLl and outer
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plastic layer. It will be further appreciated that the
barrier layer could be defined by a material other than a
metal foil as herein described. In this respect, the laminate
materials will be determined at least in part by the product
with which the tube is to be used. Still further, if the tube
were to be used for the body of a dispensing container in which
the metal foil would not contaminate the product or be corroded
therehy, the metal foil alone could define the core, or could
define the inner layer of a laminate core. The method of the
present invention advantageously enables a tube to be formed
without thermally bonding the overlapping marginal edges of
the core, thus avoiding the e~pense of equipment for this pur-
pose, eliminating the need for and the expense of providing
thermoplastic layers on opposite sides of the core laminate
for heat sealing, and thus increasing the selection of core
materials and combinations thereof in a laminated core structure.
Accordingly, it will be appreciated that many embodiments of
the present invention can be made and many changes can be made
in the embodiments herein illustrated and described, whereby
it is to be distinctly understood that the foregoing descrip-
tive matter is to be interpreted merely as illustrative of the
invention and not as a limitation.
