[0001] This invention relates to easy-open containers for packaging products under pressure,
such as biscuit and bread dough and the like. More specifically, this invention relates
to an easy-open container having a spirally-wound bodywall layer, interior barrier
liner layer and outer label layer forming an easy-open seam extending spirally between
the ends of the container and being provided with a reinforcing and tear strip extending
along the easy-open spiral seam.
[0002] Easy-open composite containers for packaging products under pressure, particularly,
refrigerated dough products and the like, constitute a significant commercial consumer
product. Typically, these containers are formed of a spirally-wound paperboard or
board stock bodywall layer and an interior liner layer which may be a laminate including
craft paper, foil and/or polymer plys, and exterior label layer. The spirally-wound
bodywall layer usually includes a butt joint formed by the adjacent edges of the bodywall
layer and forming a spiral seam extending from one end of the container to the other.
The exterior label layer surrounds the bodywall layer and covers or bridges the spiral
seam to reinforce such seam and prevent premature opening along the spiral seam.
[0003] Commercially significant containers of this type are disclosed in commonly assigned
U.S. Patent No. 3,981,433 which is directed to a one-step easy-open container including
an inner liner layer having a pleat positioned opposite the spiral butt joint. When
the outer label layer is removed, the dough and liner expand outwardly together as
the liner layer pleat begins to unfold and the result of pressure on the container
body causes the butt joint to open. This in turn automatically allows the inner liner
to expand further and automatically open by the rapidly expanding dough thereby allowing
access to the dough in the interior of the container through the spirally easy-open
seam of the container.
[0004] The outer label layer surrounding the spiral seam in containers of this type is an
important structural component of the container because the outer label layer bridges
the butt joint of the spiral seam and maintains it in closed position. Accordingly,
the label layer must utilize materials which are strong enough to prevent premature
opening of the container. Such structural requirements for the label layer prevent
the use of more economical low strength sheet materials for construction of the label
layer.
[0005] An additional problem which is present in containers of this type having easy-open
spiral seams is removal of the portion of the label layer bridging such spiral seam
so as to allow easy-opening thereof. Various mechanisms have been provided for removing
the label layer from its bridging relationship with such easy-open spiral seam including
providing a "collar cut" through the label layer and a weak adhesive between the label
layer and the bodywall layer so that the label layer may be removed circumferentially
around the container and totally off of the bodywall layer. This type of opening feature
is shown in U.S. Patent No. 3,241,739 which also discloses extending the liner layer
through the easy-open seam and tearing such extending portion of the liner layer away
as the entire label layer is removed around a collar cut to effect easy-opening.
[0006] More recently, an overlapped edge joint in the bodywall layer for the spiral seam
has been proposed in commonly assigned U.S. Patent No. 5,251,809 to provide reinforcement
to the easy-open spiral seam and to allow the use of lower quality label layers. In
addition, it has also been proposed in commonly assigned U.S. Patent No. 5,076,440
to provide a folded-over portion in the label layer to extend along the butt joint
of the easy-open spiral seam to reinforce such spiral seam and allow the use of generally
lower quality materials in the label layer. Other devices have been proposed to assist
in tearing of the label layer along the easy-open spiral seam only without removal
of the entire label layer.
[0007] It is the object of this invention to provide an easy-open container for packaging
products under pressure and which provide an improved reinforcing and tear strip feature
along the easy-open spiral seam to allow for the use of lower quality materials in
the label layer and which reinforces such easy-open seam and enhances opening of the
easy-open container through the tear strip which tears along the spiral seam and does
not require removal of the entire label layer.
[0008] It has been found by this invention that the above object may be accomplished by
providing an easy-open container particularly adapted for packaging products under
pressure and which includes generally the following.
[0009] A paperboard bodywall layer in strip form is spirally-wound and defines a substantially
cylindrical container having opposed ends. The bodywall layer has longitudinal edges
lying adjacent each other and forming a butt joint or an overlapped skived edge joint
to thereby define an easy-open spiral seam extending between the opposed ends of the
container. A flexible barrier liner layer in strip form is spirally-wound inside the
bodywall layer in superimposed position therewith and is wider than the bodywall layer
to define longitudinal edge portions on each side thereof which extends transversely
beyond the bodywall layer side edges. The liner edge portions extend through and out
of the butt joint or at least one of the liner edge portions extends through a skived
overlapped edge joint and is positioned on the outside of the bodywall layer in folded-over
superimposed position therewith.
[0010] A flexible label layer in strip form is spirally-wound outside the bodywall layer
and the folded-over liner edge portions in superimposed position therewith and has
longitudinal edges overlapped with each other. The label layer is positioned in bridging
relation to the easy-open spiral seam and the folded-over liner edge portions. A tab
cut extends through the uppermost of the overlapped label layer edge portions and
inwardly from the outer edge thereof to generally the outer edge of the folded-over
liner layer edge portions to define a tear tab to be used in easy-opening of the container.
[0011] Low strength bonding means, preferably in the form of a frangible adhesive, is positioned
between the overlapped label layer edge portions. High strength bonding means, preferable
in the form of a permanent adhesive, is positioned between the superimposed label
layer and the folded-over liner layer edge portion and between the superimposed label
layer and bodywall layer for creating a reinforcing and tear strip extending from
the tear tab along the easy-open spiral seam and between the outer edge of the uppermost
of the overlapped label layer edge portions and the easy-open spiral seam and which
includes the portion of the uppermost of the overlapped label layer edge portions
and folded-over liner edge portion bonded thereto by the high strength bonding means.
[0012] Thus, an easy-open container is formed which has an improved reinforcing and tear
strip extending along a spiral easy-open seam which strip reinforces such spiral seam
to allow the use of lower quality materials in the label layer and which provide a
tear strip which will tear through the label layer without a necessity to remove the
entire label layer and expose the spiral seam for easy-opening by the pressure of
the dough or other products in the container. A preferred method of manufacturing
this improved easy-open container will be described in the detailed description set
forth below.
[0013] Preferred embodiments of the various aspects of the invention will now be described
in detail, with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of an easy-open container provided according to a preferred
embodiment of the invention;
Figure 2 is a perspective view of the easy-open container of Figure 1 illustrating
functioning of the reinforcing and tear strip as the container is being easy-opened
along the spiral seam;
Figure 3 is a view, like Figure 2, illustrating a further progression in the easy-opening
of the container;
Figure 4 is a greatly enlarged fragmentary sectional view taken generally along the
Line 4-4 of Figure 1 and illustrates the construction of the easy-open seam of the
bodywall of the container together with a preferred construction of the improved reinforcing
and tear strip;
Figures 5 and 6 are cross-sectional views, like Figure 4, illustrating the banner
in which the container is easy-opened by tearing of the tear strip and the automatic
opening of the spiral seam following removal of the tear strip and the outer label
layer bridging such spiral seam;
Figure 7 diagrammatically illustrates a preferred method and apparatus for producing
the easy-open container of Figures 1-6;
Figure 8 is an enlarged fragmentary sectional view taken generally along the Line
8-8 of Figure 7;
Figure 9 is an enlarged fragmentary sectional view taken generally along the Line
9-9 of Figure 7;
Figure 10 is a greatly enlarged fragmentary sectional view, like Figure 4, of a modified
embodiment; and
Figure 11 is a greatly enlarged fragmentary sectional view, like Figure 4, of an alternative
embodiment.
[0014] In the following detailed description various preferred embodiments of the invention
are described. It will be understood, however, that the invention is not to be limited
to its preferred embodiments and although specific terms are employed in describing
the preferred embodiments, these are for the purposes of illustration only and not
for purposes of limitation. It will thus be apparent that the invention includes various
alternatives, modifications and equivalents within the scope of the appended claims,
as will be apparent to the skilled artisan.
[0015] Figures 1-6 illustrate a preferred embodiment of an easy-open container
10 constructed in accordance with the present invention. The container
10 includes a generally cylindrical body portion
12, a top end closure
14 and a bottom end closure
16. The container further includes a spirally-wound paperboard bodywall layer
17 in strip form which forms the basic shape of the cylindrical body portion
12 of the container. The bodywall layer
17 has longitudinal edges
17a lying adjacent each other and defining an easy-open spiral seam
20 extending between opposed ends of the body
12 and between end closures
14 and
16 of the container
10. In accordance with the embodiment of Figs. 1-6, the longitudinal edges
17a of the bodywall layer
17 abut each other to form a butt joint to in turn define the spiral seam
20.
[0016] This bodywall layer
17 is advantageously composed of conventional spiral-winding paperboard or board stock
having a thickness of between 0.10 and about 0.35 inch, preferably between about 0.15
and 0.30 inch, for example 0.021 inch. Board stock conventionally used in the manufacture
of spirally-wound containers is commercially available from various manufacturers
including Sonoco Products Company, Republic Paperboard Corporation and Middletown
Board Corporation. In order to function advantageously as the spirally-wound bodywall
layer
17, the board stock typically is composed of kraft or recycled paper or recycled corrugated.
The board stock can typically range from, e.g. a weight of 35 to 97 pounds per 1000
square feet and a thickness of .010 to .026 inch. In some instances the board stock
can include a weak exterior layer, e.g. a 0.003 inch exterior news.
[0017] The easy-open container
10 further includes a flexible barrier liner layer
22 in strip form spirally-wound inside the bodywall layer
17 in superimposed position therewith. The liner layer
22 is wider than the bodywall layers to define longitudinal edge portion
22a and
22b on each side thereof which extend transversely beyond the bodywall layer side edges
17a. Each of the liner layer edge portions
22a,
22b extend through the butt joint and out of the easy-open spiral seam
20 and are positioned on the outside of the bodywall layer
17 in folded-over superimposed position with each other and with the bodywall layer
17. The liner layer
22 is advantageously a barrier type, flexible sheet material, such as a polymer/foil,
a kraft/foil/polymer, a polymer/polymer, or a kraft/foil laminate. The barrier layer
22 prevents the escape of liquids, oils and, preferably, gases into and out of the container
bodywall
17 from the interior of the container
10.
[0018] The container
10 further includes a flexible label layer
25 in strip form spirally-wound outside the bodywall layer
17 and the folded-over liner layer edge portions
22a,
22b in superimposed position therewith and having longitudinal edge portions
25a overlapped with each other. The label layer
25 is positioned in bridging relationship to the easy-open spiral seam
20 and the folded-over liner layer edge portions
22a,
22b. Label layer
25 can be made of any suitable material, such as kraft paper, a polymer/foil laminate,
a kraft paper/foil laminate, or the like.
[0019] The easy-open container
10 further includes a tab cut
27 extending through the upper overlapped label layer edge portion and inwardly from
the outer edge thereof to generally the outer edge of the folded-over liner layer
edge portion
22a,
22b to define a tear tab which can be easily lifted open and pulled by the user to initiate
easy-opening of the container
10 in a manner to be described below.
[0020] Low strength bonding means
30 is positioned between the overlapped label layer edge portions
25a and between the folded-over liner layer edge portions
22a,
22b. High strength bonding means
32 is positioned between the superimposed label layer
25 and the upper folded-over liner layer edge portion
22a and between the superimposed label layer
25 and bodywall layer
17 for creating a reinforcing and tear strip
35 extending from the tear tab formed by the tear cut
27 along the easy-open spiral seam
20 and between the outer edge of the uppermost of the overlapped label layer edge portions
25a and the easy-open spiral seam
20 and which includes the portion of the uppermost of the overlapped label layer edge
portions
25a and the upper of the folded-over liner layer edge portion
22a bonded thereto by high strength bonding means
32.
[0021] In a preferred form of this embodiment, the lowermost of the folded-over liner edge
portions
22b is wider than the uppermost of the folded-over liner edge portion
22a and extends beyond the outer edge thereof. Low strength bonding means
30 is positioned between the label layer
25 and the portion of the lowermost of the folded-over liner edge portions
22b extending beyond the outer edge of the uppermost of the folded-over liner edge portions
22a. The low strength bonding means
30 positioned between the overlapped label layer edge portions and between the label
layer and the portion of the lowermost of the folded-over liner edge portions
22b comprises a frangible adhesive. The low strength bonding means positioned between
the folded-over liner edge portions
22a,
22b comprises heat sealing, and the high strength bonding means comprises a permanent
adhesive.
[0022] Various adhesives can be employed as the frangible adhesive forming the low strength
bonding means
30. The tear or peel strength of this frangible adhesive will vary depending on the
materials used in the component layers of the container
10. The peel strength must be weak or less than the tear strength of the liner layer
22 and the label layer
25 so that the layers will peel rather than tear. With current material used, it has
been found that a peel strength of 0.42 to 1.99 pounds per square inch is preferred.
The frangible adhesive may include a high initial tack dextrine based adhesive commercially
available from National Starch and Chemical Corporation, Grand Prairie, Texas as "71-5626B".
This is a high solids (about 64%), high viscosity (about 2100 cps) acid modified (about
2.5 Ph) dextrine adhesive. Other frangible adhesives which can be successfully used
include heavily filled, resinous, aqueous emulsion type adhesives such as, for example
polyvinylacetate dispersed in water together with a tackifying alcohol and an inert
filler such as clay, silicon dioxide calcium carbonate, talc and the like. The inert
filler can insure that a weak discrete layer of adhesive remains between the superimposed
components of the container to thereby provide for the fracture or breaking of the
adhesive. Weak latex can be used on some films. In the alternative, a release coating,
such as a microcrystalline wax, silicone or the like can be provided on the inner
surface on either or both of the superimposed components of the container so that
the adhesive layer is readily released upon drying.
[0023] It is important that the frangible adhesive used for the low strength bonding means
30 have a high initial tack or adhesive so that the overlapped components between which
it is positioned are held together during, and immediately following, manufacture
of the container
10. It is also important that this frangible adhesive be capable of readily allowing
peeling or separating of the superimposed components between which it is positioned
upon easy opening of the container
10 by tearing the tear strip
35 along the easy-open seam
20. It has been found that heat sealing also accomplishes the purposes of a low strength
bonding means and may be conveniently formed between the overlapped liner layer edge
portions
22a,
22b during manufacture of the container
10.
[0024] Various adhesives may be employed to provide the permanent adhesive utilized for
the high strength bonding means
32. The tear or peel strength of this permanent adhesive will vary depending upon the
materials used in the component layers of the container
10. The tear or peel strength must be greater than the tear strength of the liner layer
22 and the label layer
25 so that these layers will tear when the tear strip
35 is torn along the easy-open spiral seam. With current materials used for these component
layers, it has been found that a peel strength greater than 2.20 lbs. per square inch
is necessary. The permanent adhesive may include polyvinyl alcohol with or without
clay mix, blended or reactor resins, special additives, such as manufactured by H.B.
Fuller and identified as A1940 having 4000 CPS viscosity, 55% solids and 5.0 pH, K6030
having 3050 CPS viscosity, 55% solids and 5.0 pH, H3935 having 5500 CPS viscosity,
52% solids and 5.0 pH, and by National Starch and identified as 32-1984 having 5400
CPS viscosity, 56% solids and 4.5 pH, and 32-0215 having 4500 CPS viscosity, 55% solids
and 4.0 pH.
[0025] Referring now to Figure 10, the construction of the container
10 described above with respect to Figures 1-6 may further include a flexible expansion
joint
40 positioned in the region of the easy-open spiral seam
20 and comprised of a portion of one of the liner layer edge portions
22b being folded back on itself and heat sealed to the other of the liner layer edge
portions
22a. Upon opening of the easy-open seam
20, the expansion joint
40 will expand prior to breaking to expose the contents of the container, in a manner
well understood by those with ordinary skill in the art.
[0026] Referring now to Figure 11, an alternative embodiment of the container
10 is illustrated. Like reference numerals are used in this embodiment where the components
of this alternative embodiment of the container
10 are the same and will not be further described with respect to this embodiment.
[0027] In this embodiment of the container
10 of Figure 11, the longitudinal edges
17a' and
17b' of the bodywall layer
17 are in the form of longitudinal skived edges and are overlapped with each other.
Skived edges, as is well understood by those with ordinary skill in the art, may be
formed by compressing the edges or by grinding away or cutting away a portion of the
material of the edges. The skived edges illustrated in Figure 11 are compression skived.
This embodiment also has only one of the liner layer edge portions
22a' extending through and out of the easy-open spiral seam
20 and positioned on the outside of the bodywall layer
17 in folded-over superimposed position therewith. The other of the liner layer edge
portions
22b' is positioned in overlapping relationship with the other of the liner layer edge
portions
22a on the inside of the bodywall layer
17 and may be folded back on itself to provide an expansion joint
40' and has a low strength bonding means
30 therebetween which may be in the form of heat sealing having a tear or peel strength
of 3.00 to 5.00 pounds per square inch. Otherwise, this embodiment is the same and
operates the same as the embodiment of Figures 1-6 and the embodiment of Figure 10.
[0028] Any of the above described embodiments of this invention may also preferably include
a second tab cut
28 aligned with the other tab cut
27 and extending through the uppermost of the label layer edge portions
22a to aid in initiating easy opening of the container
10 by tearing of the reinforcing and tear strip
35 along the spiral seam
20.
[0029] As may be seen particularly in Figures 4-6, the container
10 of this invention may be easy-opened by grasping the tear tab formed by the tab cut
27 and
28 which in turn initiates separation of the overlapped label edge portions
25a through the low strength bonding means
30 or frangible adhesive and separation of the overlapped liner layer edge portions
22a,
22b by fracturing the low strength bonding means
30 in the form of a heat seal. This will in turn cause tearing of the upper of the folded-over
liner layer edge portions
22a at the spiral seam
20 along with the uppermost label layer edge portion
25a because of the strength of the high strength bonding means
32 or permanent adhesive holding the upper label layer edge portion to the upper liner
layer edge portion
22a, holding the label layer
25 to the body layer
17 and holding the lowermost of the folded-over liner layer edge portions
22b to the bodywall layer
17. This causes the reinforcing and tear strip
35 to tear down along the spiral seam
20, as shown particularly in Figures 2 and 3. This causes the pressurized product or
dough within the container
10 to expand through the spiral seam
20, as shown in Figures 3 and 6, to self-open the spiral seam
20 and the container
10 in a manner well understood by users of these types of containers for pressurized
products.
[0030] Thus, a reinforcing and tear strip
35 has been provided in the container
10 which will initially reinforce the easy-open spiral seam
20, and which will easily separate from the components to which it is attached by fracture
of the low strength bonding means
30 to tear along the spiral seam
20 for easy opening thereof without the necessity of removal of the entire label layer
25. This also allows the advantage of the use of weaker or more economical materials
in the label layer than would be possible without the use of such reinforcing and
tear strip
35.
[0031] Referring now to Figures 7-9, a preferred method and apparatus for producing the
easy-open container of Figures 1-6 is diagrammatically illustrated.
[0032] As may be seen, a flexible barrier liner layer
22 in strip form is provided from any suitable liner supply. A paperboard bodywall layer
17 in strip form is also provided from any suitable source. The bodywall layer
17 is of a width narrower than the liner layer
22 and is positioned on top of the liner layer
22 in superimposed position so as to define longitudinal edge portions
22a and
22b on each side of the wider liner layer
22 and which extend transversely beyond the bodywall side edge portions
17a when in superimposed position. Preferably, the edge portion
22b is wider than the edge portion
22a.
[0033] A high strength bonding means
32 in the form of a permanent adhesive, as described above, is applied across the central
portion of the upper surface of the liner layer
22 and of a width generally the same as the width of the narrower bodywall layer
17 by a suitable roller applicator device
50 or other suitable means. The superimposed bodywall layer
17 and liner layer
22 are fed longitudinally at a desired angle to a stationary mandrel
52 and are spirally wound thereon in a manner well understood by those with ordinary
skill in the art.
[0034] While the superimposed bodywall layer
17 and liner layer
22 are being fed to the mandrel
52, a high strength bonding means
32, preferably in the form of a permanent adhesive, is applied along the bodywall edge
portion
17a adjacent to the wider liner layer edge portion
22b by a suitable roller adhesive applicator
53 or other suitable device and this wider liner layer edge portion
22b is folded over onto the adjacent bodywall edge portion
17a by suitable folder device
54 so that the permanent adhesive is positioned therebetween to form a high strength
bond
32. A tab cut
28 is also formed in the narrower liner layer edge portion
22a during feeding of the superimposed bodywall layer
17 and liner layer
22 to the mandrel
52 by a suitable tab cut device
55.
[0035] As the superimposed bodywall layer
17 and liner layer
22 with folded-over liner layer edge portion
22b are wound onto the mandrel
52, the narrower liner layer edge portion
22a will overlap the folded-over liner layer edge portion
22b on the previous revolution of the superimposed bodywall layer
17 and liner layer
22 on the mandrel
52 so that such liner layer edge portions
22a and
22b are overlapped and superimposed with each other. A low strength bond
30 is formed between these overlapped liner layer edge portions
22a and
22b by heat sealing through a suitable heat sealer device
56. This spiral winding also forms a butt joint relationship of the edge portions
17a of the bodywall layer
17 to form a continuous tube having a spiral seam
20 therein and wherein each of the liner layer edge portions
22a and
22b extend through such butt joint and out of the spiral seam
20.
[0036] The thus formed continuous tube is fed forwardly along the mandrel
52 in a manner well understood by those with ordinary skill in the art by a belt device
60. During such forward feeding of the continuous tube, a flexible label layer
25 is provided from a suitable supply and is fed longitudinally at a desired angle to
the mandrel
52. While the label layer
25 is being fed to the mandrel
52, a tab cut
27 is preferably cut into one of the label layer edge portions
25a by a suitable tab cutting device
62.
[0037] A high strength bonding means
32 in the form of a permanent adhesive is applied along the bottom surface of the label
layer
25 to extend from the outer edge of one longitudinal edge portion
25a toward the other longitudinal edge portion
25a having the tab cut
27 therein, but leaving this label layer outer edge portion
25a uncoated with the permanent adhesive. Thereafter, a low strength bonding means
30 in the form of a frangible adhesive is applied along the bottom surface of the liner
layer edge portion
25a which was not coated with the permanent adhesive. The label layer
25 is spirally-wound in superimposed position onto the continuous tube formed by the
superimposed bodywall layer
17 and liner layer
22 in the manner discussed above so that the label layer edge portions
25a are in overlapped relationship with each other and have the frangible adhesive positioned
therebetween for forming a low strength bonding means
30.
[0038] The label layer
25 is positioned in bridging relationship to the spiral seam
20 and the superimposed liner layer edge portions
22a,
22b on the outside of the bodywall layer
17 and in superimposed position to the remainder of the bodywall layer
17 so that the overlapped label layer edge portions
25a are adjacent to but not directly superimposed thereon and so that a low strength
bonding means
30 is formed between the overlapped label layer edge portions
22a and a high strength bonding means
32 is formed between the superimposed label layer
25 and the other of the liner layer edge portions
22a and the superimposed label layer
25 and bodywall layer
17. The tab cuts
27 and
28 are also positioned in alignment with each other by this spiral winding.
[0039] Thereafter, the thus spirally-wound continuous tube having bodywall layer
17, liner layer
22 and label layer
25 are fed forwardly on the mandrel
52 to a cutting station where suitable cutting devices
65 cut the continuous tube into individual lengths for containers
10. These individual container lengths may then be fed to a suitable end applying mechanisms
while being filled with dough or other products under pressure so as to form filled
easy-open containers
10.
[0040] Thus, it may be seen, that this invention has provided an improved easy-open container
10 which has an improved reinforcing and tear strip
35 extending along a spiral easy-open seam
20 which strip
35 reinforces the spiral seam
20 to allow the use of lower quality or lower strength materials in a label layer
25 and which provides a tear strip
35 which will tear through the label layer
25 and expose the spiral seam
20 for easy-opening by the pressure of the dough or other products in the container.
A method has also been provided which may be utilized on conventional spiral winding
equipment without substantial modifications or new devices therein.
1. An easy-open container particularly adapted for packaging products under pressure
and comprising:
a spirally-wound paperboard bodywall layer in strip form defining a substantially
cylindrical container having opposed ends, said bodywall layer having longitudinal
edges lying adjacent each other to thereby define an easy-open spiral seam extending
between said opposed ends;
a flexible barrier liner layer in strip form spirally-wound inside said bodywall layer
in superimposed position therewith and being wider than said bodywall layer to define
longitudinal edge portion means on each side thereof which extend transversely beyond
said bodywall layer side edges; said liner edge portion means extending through and
out of said easy-open spiral seam and positioned on the outside of said bodywall layer
in folded-over superimposed position therewith;
a flexible label layer in strip form spirally-wound outside said bodywall layer and
said folded-over liner edge portion means in superimposed position therewith and having
longitudinal edge portions overlapped with each other, said label layer being positioned
in bridging relation to said easy-open spiral seam and said folded-over liner layer
edge portion means;
a tab cut extending through the upper of said label layer edge portions and inwardly
thereof to generally the outer edge of said folded-over liner layer edge portion mean
to define a tear tab to be used in easy-opening of said container; and
low strength bonding means positioned between said overlapped label layer edge portions,
and high strength bonding means positioned between said superimposed label layer and
folded-over liner layer edge portion means and between said superimposed label layer
and bodywall layer for creating a reinforcing and tear strip extending from said tear
tab along said easy-open spiral seam and between the outer edge of the uppermost of
said overlapped label layer edge portions and said easy-open spiral seam and which
includes the portion of the uppermost of said overlapped label layer edge portions
and said folded-over liner layer edge portion means bonded thereto by said high strength
bonding means.
2. An easy-open container, as set forth in Claim 1, in which said low strength bonding
means comprises a frangible adhesive, and in which said high strength bonding means
comprises a permanent adhesive.
3. An easy-open container particularly adapted for packaging products under pressure
and comprising:
a spirally-wound paperboard bodywall layer in strip form defining a substantially
cylindrical container having opposed ends, said bodywall layer having longitudinal
edges lying adjacent each other and defining an easy-open spiral seam having a butt
joint and extending between said opposed ends;
a flexible barrier liner layer in strip form spirally-wound inside said bodywall layer
in superimposed position therewith and being wider than said bodywall layer to define
longitudinal edge portions on each side thereof which extend transversely beyond said
bodywall layer side edges each of said liner layer edge portions extending through
said butt joint and out of said easy-open spiral seam and positioned on the outside
of said bodywall layer in folded-over superimposed position with each other and with
said bodywall layer;
a flexible label layer in strip form spirally-wound outside said bodywall layer and
said folded-over liner layer edge portions in superimposed position therewith and
having longitudinal edge portions overlapped with each other, said label layer being
positioned in bridging relation to said easy-open spiral seam and said folded-over
liner layer edge portions;
a tab cut extending through the upper of said label layer edge portions and inwardly
from the outer edge thereof to generally the outer edge of said folded-over liner
layer edge portions to define a tear tab to be used in easy-opening of said container;
and
low strength bonding means positioned between said overlapped label layer edge portions
and between said folded-over liner layer edge portions, and high strength bonding
means positioned between said superimposed label layer and the upper folded-over liner
layer edge portion and between said superimposed label layer and bodywall layer for
creating a reinforcing and tear strip extending from said tear tab along said easy-open
spiral seam and between the outer edge of the uppermost of said overlapped label layer
edge portions and said easy-open spiral seam and which includes the portion of the
uppermost of said overlapped label layer edge portions and the upper of said folded-over
liner layer edge portions bonded thereto by said high strength bonding means.
4. An easy-open container, as set forth in Claim 3, wherein the lowermost of said folded-over
liner edge portions is wider than the uppermost of said folded-over liner edge portions
and extends beyond the outer edge thereof, and wherein low strength bonding means
is positioned between said label layer and the portion of the lowermost of said folded-over
liner edge portions extending beyond the outer edge of the uppermost of said folded-over
liner edge portions.
5. An easy-open container, as set forth in Claim 4, in which said low strength bonding
means positioned between said overlapped label layer edge portions and between said
label layer and the portion of the lowermost of said folded-over liner edge portions
comprises a frangible adhesive, said low strength bonding means positioned between
said folded-over liner edge portions comprises heat sealing, and said high strength
bonding means comprising a permanent adhesive.
6. An easy-open container particularly adapted for packaging products under pressure
and comprising:
a spirally-wound paperboard bodywall layer in strip form defining a substantially
cylindrical container having opposed ends, said bodywall layer having longitudinal
skied edges overlapped with each other to thereby define an easy-open spiral seam
extending between said opposed ends;
a flexible barrier liner layer in strip form spirally-wound inside said bodywall layer
in superimposed position therewith and being wider than said bodywall layer to define
a longitudinal edge portion on each side thereof which extend transversely beyond
said bodywall layer side edges; one of said liner layer edge portions extending through
and out of said easy-open spiral seam and positioned on the outside of said bodywall
layer in folded-over superimposed position therewith and the other of said liner layer
edge portions being positioned in overlapping relation with the one of said liner
layer edge portions on the inside of said bodywall layer;
a flexible label layer in strip form spirally-wound outside said bodywall layer and
said folded-over liner layer edge portion in superimposed position therewith and having
longitudinal edge portions overlapped with each other, said label layer being positioned
in bridging relation to said easy-open spiral seam and said folded-over liner layer
edge portion means;
a tab cut extending through the upper of said label layer edge portions and inwardly
from the outer edge thereof to generally the outer edge of said folded-over liner
layer edge portion mean to define a tear tab to be used in easy-opening of said container;
and
low strength bonding means positioned between said overlapped label layer edge portions
and between said superimposed folded-over liner layer edge portion and bodywall layer
and between said overlapped liner layer edge portions, and high strength bonding means
positioned between said superimposed label layer and folded-over liner layer edge
portion and between said superimposed label layer and body layer for creating a reinforcing
and tear strip extending from said tear tab along said easy-open spiral seam and between
the outer edge of the uppermost of said overlapped label layer edge portions and said
easy-open spiral seam and which includes the portion of the uppermost of said overlapped
label layer edge portions and said folded-over liner layer edge portion bonded thereto
by said high strength bonding means.
7. An easy-open container, as set forth in Claim 6, in which said overlapped skied edges
of said bodywall layer comprise edges which have been compressed.
8. An easy-open container, as set forth in Claim 6, in which said low strength bonding
means positioned between said overlapped label layer edge portions and between said
superimposed folded-over liner layer edge portion and bodywall layer comprises frangible
adhesive, said low strength bonding means positioned between said overlapped liner
layer edge portions comprises heat sealing, and said high strength bonding means comprises
permanent adhesive.
9. An easy-open container as set forth in Claim 1 or 3, including a second tab cut aligned
with the other said tab cut and extending through the upper of said folded-over liner
layer edge portion toward said easy-open spiral seam.
10. An easy-open container, as set forth in Claim 1, 3 or 6, in which one of said liner
layer edge portions is folded back on itself and heat sealed to the other of said
liner layer edge portions to define an expansion joint positioned in the region of
said easy-open spiral seam.
11. An easy-open container, as set forth in Claim 2, 5 or 8, in which said frangible adhesive
comprises an adhesive having a peel strength less than the tear strength of said liner
layer and said label layer.
12. An easy-open container, as set forth in Claim 2, 5 or 8, in which said permanent adhesive
comprises an adhesive having a peel strength greater than the tear strength of said
liner layer and said label layer.
13. An easy-open container, as set forth in Claim 2, 5 or 8, in which said frangible adhesive
comprises an adhesive having a peel strength less than the tear strength of said liner
layer and said label layer, and said permanent adhesive comprises an adhesive having
a peel strength greater than the tear strength of said liner layer and said label
layer.
14. A method of manufacturing an easy-open container comprising the steps of:
providing a flexible barrier liner layer in strip form and a paperboard bodywall layer
in strip form and of a width narrower than the liner layer;
positioning the bodywall layer in superimposed position on the liner layer so as to
define longitudinal edge portions on each side of the wider liner layer which extend
transversely beyond the bodywall layer side edges;
feeding the superimposed liner layer and bodywall layer to a mandrel, while folding-over
one of the liner layer edge portions onto the bodywall layer and forming a high strength
bond therebetween;
spirally-winding the superimposed liner layer and bodywall layer with the folded-over
liner layer edge portion on the mandrel in butt joint edge relationship of the bodywall
layer to form a continuous tube having a spiral seam and with each of the liner layer
edge portions extending through the butt joint and out of the spiral seam, while positioning
the other of the liner layer edge portions in superimposed position on the folded-over
liner layer edge and forming a low strength bond therebetween;
spirally-winding a flexible label layer in strip form onto the continuous tube on
the mandrel with the longitudinal edges in overlapped relationship and positioning
the label layer in superimposed bridging relation to the spiral seam and the superimposed
liner layer edge portions on the outside of the bodywall layer and in superimposed
relation to the remainder of the bodywall layer so that the overlapped label layer
edges are adjacent to but not directly superimposed thereon, while forming a low strength
bond between the overlapped label layer edges and a high strength bond between the
superimposed label layer and the other of the liner layer edge portions and the superimposed
label layer and bodywall layer; and
cutting the thus wound continuous tube into individual container lengths.
15. A method of manufacturing an easy-open container comprising the steps of:
providing a flexible barrier liner layer in strip form and a paperboard bodywall layer
in strip form and of a width narrower than the liner layer;
positioning the bodywall layer in superimposed position on the liner layer so as to
define longitudinal edge portions on each side of the wider liner layer which extend
transversely beyond the bodywall side edges and so that one of the liner layer edge
portions is wider than the other of the liner layer edge portions, while applying
a permanent adhesive between the superimposed bodywall layer and liner layer to form
a high strength bond therebetween;
feeding the superimposed liner layer and bodywall layer to a mandrel, while folding-over
the wider one of the liner layer edge portions onto the bodywall layer, while applying
a permanent adhesive between the folded-over portion of the one liner layer edge portion
and the bodywall layer to form a high strength bond therebetween;
spirally-winding the resulting liner layer and bodywall layer onto the mandrel in
butt joint edge relationship of the bodywall layer to form a continuous tube having
a spiral seam and with each of the liner layer edge portions extending through the
butt joint and out of the spiral seam, while positioning the other narrower of the
liner layer edge portions in superimposed position over the folded-over liner layer
edge portion and heat sealing the thus superimposed liner layer edge portions to form
a low strength bond therebetween;
spirally-winding a flexible label layer in strip form onto the continuous tube on
the mandrel with the longitudinal edges in overlapped relationship and positioning
the label layer in superimposed bridging relation to the spiral seam and the superimposed
liner layer edge portions on the outside of the bodywall layer and in superimposed
relation to the remainder of the bodywall layer so that the overlapped label layer
edges are adjacent to but not directly superimposed thereon, while applying a frangible
adhesive along one edge portion of the label layer to position the frangible adhesive
between the overlapped label layer edges and the superimposed label layer and wider
liner layer edge portion extending beyond the narrower label layer edge portion to
form a low strength bond therebetween, and applying a permanent adhesive along the
remainder of the label layer to position the permanent adhesive between the superimposed
label layer and the narrower of the liner layer edge portions and the superimposed
label layer and bodywall layer to form a high strength bond therebetween; and
cutting the thus wound tube into individual container lengths.
16. A method of manufacturing an easy-open container, as set forth in claim 14 or 15,
including the additional step of
forming a tab cut through the one of the label layer edges which is overlapped on
top of the other of the label layer edges so as to form a tab cut extending through
the label layer and inwardly from the outer edge of the uppermost of the overlapped
label layer edges to generally the outer edge of the folded-over liner layer edge
portion to define a tear tab to be used in opening of the container.
17. A method of manufacturing an easy-open container, as set forth in claim 16, including
the further step of
forming a tab cut through the narrower of the liner layer edge portions in a position
to mate with the tab cut formed in the top label layer edge when all of the layers
are spirally wound so that the tear tab extends through the upper of the superimposed
liner layer edge portions.