Note: Descriptions are shown in the official language in which they were submitted.
13 BACKG~OUl~D OF THE INV~E~TION
14 ~ This invention relates to containers and, more par-
16 ticularly, it relates to containers constructed of relatively
16 low strength materials which are well-suited for packaging
17 products requiring increased structural integrity and a hermetic
18 seal, such as food and/or pressure-producing products.
It is very desirable to have an inexpensive container
20 suitable for packaging various food items and pressure-producing
21 products, such as carbonated beverages ana beer. However,
22 suitable containers for such products have been rather expensive
23 due to the high strength characteristics necessary to maintain
24 the hermetic seal. ~ -
In recent years, there have been introduced a number
26 of different types of lightweight, composite containers con-
27 structed of low strength materials which are considerably less
28 expensive than the commonly-used tin plate and aluminum con-
29 tainers~ Such inexpensive containers normally are comprised
8~ o ~ cylindrica1 composite can body closed at both ends by
31 :
.
82
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,
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_ . 14800
F~rm Z33 C ~ 1138~
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1 metal caps which are attached to the body by a standard double-
2 seaming method In this standard double-seaming method, a
8 curved extension of the metal end is folded over together with
4 a flange portion on the fiber can body so as to form a double-
6 seam joint. Such standard fiber containers have expexienced
6 di~ficult~ in packaging cer-tain food- items and certain pressùre-
q producing products because the joint between the metal ends -
8 and the iber body has;not exhibited sufficient strength to
; . 9 maintain a hermetic seal and to withstand the pressure of the
10 products container therein. Thus, end seam failure was fre-
11 ~uently experienced when attempts were made to uso standard.
12 double-seamed fiber cans for packaging pressure-producing
18 products. Thus, even though standard fiber containers are
1~ much lighter in weight and less expensive than.the stronger
1C metal containers, they have not been suitable for use in pack-
1~ aging certain food items and some préssure-producing products.
.
17 An improved hexmetically sealed composite container
18 was provided in my U. S. Patént ~o. 3,580,464 which issued on .
19 May 25, 1971. The improved composite container disclosed in
20 this-patent features the use of a compound matexial on the
21 metal ends which, when heated, will form a bond with a thermo-
22 plastic material incorporated into the inner liner of the com-
~g posite can body. Thus, this configuration provided both ~a
2~ mechanical double-seamed joint and a chemical-type bond which
26 aided in providing a hermetic seal and withstanding the increased
26 pxessure of pressure-producing products. However, it has been
27 found that while the configuration of my U. S. Patent No.
28 3,580,464 was a considerable improvement over the existing
29 pxior art composite containers, it does not provide the neces-
80 sary structural integrity required for packaging and shipping certain
81 -
82
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~ . 14800
ForM ~33 C. ~ ~3
1~38793
food items and other pressure-producing products. It has been.
found that during shipping certain impacts-to the side area
of the double-seamed end configuration could result in a reduc-
4 tion of the hermetic seal and loss of pressure from within the
~ container
6 Thus, there is a continuing need for~ and it is a~
7 object of this invention to provide, an inexpensive container
8 w~ich provides improved strength to maintain a hermetic seal
g for successful packaging of ~ood ite~s and pressure-producing
lo products
11 Other objects, features and advantages of this inven-
1Z tion will become obvious to those skilled in the art upon
18 reference to the following detailea description and the drawings
1~ illustrating a preerred embodiment thereof.
16 ~N T~E DRAwI~Gs
16 FIG. l is a front elevational view.of a lightweight
17 composite container with parts broken away in section and
18 incorporating the metal ena attaching means of this invention.
1~ FIG. 2 is an enlarged sectional view of a compounded
20 container end and the extended flange poxtion of a can body to
21 which it is to be joined~
.22 FIG. 3 is a sectional view of the components of
2g FIG. 2 showing them in the final seaied relationship.
. . 24 SUMMAR~ OF THE I~VENTION .: .
2~ In general, this invention provides a substantially
26 rigid container which may be constructed of fiber, plastic,
27 lightweight metal, or combinations of such materials and which
8 is adapted to provide a strong double-seamed joint between the
zg metal end members and the can body wall This invention pro-
so vides for the use of metal ends which include compound materiaL
s2
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por~a 2J3 C'~` 1138793 C
.
1 throughout their curl area and extended flange portions-on the
2 composite can body to facilitate an improved joint and seal
~ between the metal ends and the can body. In addition, the
4 compound is adapted to form a bond with an inner liner layer
6 on the can bod~.
6 DESCRIPTIO~ OF THE PREFERRED EMBODIME~T
7 Although the preferred embodiment, as shown in
8 FIGS. 1-3, features a composite type container, it should be
g clear that thé invention is equally well-suited to be used in
o combination with a thin-walled container constructed of plastic
11 and other materials.
12 More particularly, FIG. 1 shows a cylindrical con-
18 tainer 10 formed from a thin-walled composite can body 12 and
1~ a pair of metal end closures 14 and 16.
1~ The construction of the cylindrical composite can
16 body 12 can best be seen by reference to FIGS. 2 and 3. The
Iq can body 12 is comprised of a layer of structural material 18
18 sandwiched between an outer label 19 and an innex liner 20
1~ which is laminated or bonded to the inside of the structural
20 material 18. It should be understood that a variety of different
21 materials can be utilized to produce the structural material
22 layer 18, the outer label lg, and the inner liner 20. As
.. . .
23 examples of suitable such materials, the inner liner 20 may be
2~ formed of a lamination of 01001 in. polypropylene film/0.00035 in
2G aluminum foil/0 0005 in. low-density polyethylene/and 25 lb per
26 ream paper, which may be extensible graae kraft paper or 3/4 mil
27 surlyn/0.00035 "aluminum foil/O.OOos~ low-density polytheylenej
28 25 lb. per ream paper. The structural material layer 18 coula
29 be formed from a number of layers of can stock grade natural
80 kraft. The outer label 19 may be eithex 0.001 high-density
~1 ' ' .
82
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14800
Fo~ 33 - 1138793
I polyethylene~25 lb. per ream natural kraft Eaper or 0.0003
2 aluminum foil/25 lb. per ream natural krat paper. In addition~
8 40-55 lb. per ream coatea bleached paper grades may also be
4 used as label stoc~. The high-density polyethylene, aluminum
6 foil, or coated.bleached paper in these e.~amples for the outer
6 label 19 would serve,as an outer protective coating for the
7 structural material~ Likewise, the inner liner 20 formed of
8 polyp~opylene f~m, aluminum foil, and low-density polyethylene ',
9 is positioned so as to be in contact with the pxoduct being
lo contained within the,container 10 and keeps the product out
11 of contact with ,he structural layer 18 . .
12 , An important feature of this invention is the pro-
1~ vision of an extended length attaching flange 22 at each end
1~ of the fiber can body 12. Typical flange extension obtained
1~ in conventional flanging methods now being used in the manu-
16 facture of composite cans resuIts in a flange length (see "L"
17 in FIG- 2) of .030--050 in- measured from-outer bodywall surface
18 depending on the can size,and the materials used. Flange -
19 extension obtained in this invention results in a flange length
20 of ,075-.090 in. It is suggested that the can,body be formed
21 approximately 3/32 of an inch longer than standaxd can bodies
22 currently used for the same size.can to provide additional
..
23 material to form the extended length flanges 22. It is further
2~ suggested that the extended length flanges 22 be formed as
2S shown in FIG 2 so that they are positioned in a generally
26 perpendicular relationship with the can body 12.
27 The metal end closures 14 and 16 are of a standard
28 type used in connection with hermetically sealea cans and may
29 be identical with each other. For the purpose of illustration,
80 FIGS 2 and 3 depict the sequence of uniting the end closure 16
~2 ~5-
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For~ 233 ( ~3 li 38793 C
1 to the can body 12. It should be understood that the end
2 closure 14 is attached to the opposite end of the can body
8 12 in an identical procedure. The metal end closure 16, as
shown in FIGS. 2 and 3, includes a center panel 24, a chuck
~ wall 26, a shoulder area 28, a seaming panel 30, and a cover
6 hook area 32. An important feature of this invention is the' '
provision of a quantity of compounding composition 34 which is
8 strategically positioned across the entire seaming panel 30
g and extend$ partially into the shoulder area 28 and the cover
lo hooX area 32~ Such compound normally has been positioned
11 only in the shoulder area of a metal end which is to be double-
12 seamed to a composite can body. Thus, as will be seen in
18 re,erence to FIG. 3, the use of the extended flange 22 and
the positioning of the compound material 34 results in a ~uch
1~ increased contact area between the metal end and the can body
16 inner liner when they are double-seamed together to form the
configuration of FIG 3. Although any suitable compound may
be used, a recommended e~ample of a suitable such end lining
19 compound is Compound No. 1105, which is manufactured by the
20 Dewey & Almy Chemical Division o~ W. R. Grace and Company.
21 As can be seen in the transition of FIG. 2 to FIG. 3, when the
22 metal end closure 16 is double-seamed into engagement with the'
, . , . ' . ':
23 extended flange 22, a structurally sound joint is formed be-
24 tween the metal end closure 16 and the can body 1~., The c,on-
26 figuration of this invention results in a relatively lon,g
z6 surface area contact between the compouna material 34 and the
z7 inner liner 20 on'the can body to thereby form a rather exten-
z8 sive bonding area to create an effective hermetic seal between
29 the metal end closure and the can body. Both internal pressure
~ build-up and physical damage to the end chine area tend to
sl .
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--- 1138793
.
1 pull the chuck wall area 26 aw~y from the can body, thereby
2 damaging the primar~ seal which is formed in this area. The
subject invention avoids this problem b~ relocating the pri-
mary seal ta the extende~ flange and curl are,a. These areas
6 tend to be tightened thereby creating an improved primary
6 seal during distortion of the chuck wall area.
7 Thus, the'use of the extended flange 22 and the
8 positioning of the compound 34 creates both an effective her-
g metic seal and a structural joint having considerably improved
lo strength over previously utilized double-seamed joint For
~1 example, abuse tests comparing the new improved conæiguration
12 Of this invention with a standard double-seamed.joint'have
13 shown that 26.4% of the standard double-seamed joint cans
14 exhibited a loss of hermetic seal due to damage of the end
1~ seam compared with only 2.8~ of the cans featuring the improved
16 extended flange concept of this invention~ '
It should be noted that the metal end closures may.
'18 be heated as taught in my previously mentioned U S. Patent
19 ~~ 3,580,464 so as to aid in the bonding of the compound material
20 with the inner liner on the fiber can body.. However, it has,
21 also been found that the use of the extended flange,and the
22 positioning of the'compound of this invention will provide
23 both a vastly improved hermetic seal and a stronger aouble-',
24 seamed joint even without the specific application of heat
2~ when compared with standard double-seamed joints. Hence, it
26 is clear that the unique structuxe of the subject invention
27 results in a lightweight and inexpensive contai~er which exhibits
28 strength properties heretofore unknown in such containers~ and
z~ is capable of both providing an improved hermetic seal for
8~ food products and withstanding the pressures associated with
~1
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1~800
f`, f
Fo~m,333 ~ C~-3 C,~
` "` 1138793
1 pressure-producing products~ such as carbonated beverages
2 and beer. As a result, the desirable use o~ inexpensive,
8 lightweight containers has been extended to additional products
beyond those that are currently packaged in such containexs~
'.
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