CA1218946A - Composite container construction for packaging material under pressure or vacuum conditions - Google Patents

Abstract

AN IMPROVED COMPOSITE CONTAINER
CONSTRUCTION FOR PACKAGING MATERIALS
UNDER PRESSURE OR VACUUM CONDITIONS
ABSTRACT
A container is formed by providing a composite wall with reinforcing strips which surround the ex-terior of the wall at its opposite ends. The con-tainer is capped by end closures the edges of which engage the reinforcing strips to deform the strips to both overlap the closure edges and compress the con-tainer wall between the strips and the closures.

Description

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AN INPROVED CO~POSITF, CONTAINFR
CONSTRUCTION FOR PACRAGING M~TERIALS
UNDER PRESSURE, OR VACUUM CONDITIONS

BACKGROUND OF-T~E INVENTIOW
The present invention relates to an improved com- -posite ~ontainer construction capable of retaining goods packaged under.either vacuum or pressure condi-tions. Although the invention may be utilized in em-5 bodiments wherein the basic component of the container wall is either a polymeri~ or a fibrous material, the invention is particularly suited to applications in whiah the container wall is a composite fiber construc- :
tion. Accordingly, the discussion to follow will be 10 directed primarily to such an embodiment~
A composite fibex container wall principally is formed from fibrous materials (such as kraft, chip or t jute paper) and therefore requires that the inner sur face of the container be completeIy sealed and that .
15 the metal closures on its o~posite ends be tightly locked in sealing reIationship onto the container. .
Addition~lly, the container ~ust be capable of easy opening.
Prese~t methods of manufacturing composite fiber 20 container ~odies.involve convolute or spiral winding techniques so as to ~orm a tube. The materials used in forming spiral wound and convolute tubing are pli-able by nature and therefore are susceptible to dis placement and fracturing under pressure or vacuum con- :
~5 ditions. For this reason, either immediate leakage occurs due to fracturing of the container body, or eventual slow leakage results from a process known in the industry as "creep". In the latter case, the ~ ~ !39~6 metal end closures tend to work their way loose from the container over a period of timeO
Because of such problems, composite containers have not been suitable for certain markets where the product is packaged under pressure or vacuum condi-tions. Examples of such products are tennis balls, coffee, nuts, low pressure aerosols, and the like~

SUMMARY OF THE INVENTION
According to the present invention, a pressure or vacuum-type composite cont~iner is produced by provid-ing a reinforcing strip to the cut edges at opposite ends of the container. Such strips preferably are a metallic material which can be flanged. These strips are made integxal with the container ~y being applied as bands to the composite tubing prior to its being cut into container lengths. The bands are spaced along the tubing at the points where it is cut so that each end of a container includes a strip of a rein-forcement band. After the cutting operation, the re-inforcing strips are flanged so as to be adapted toreceive metallic end closures.
To seal a container end, the edge of the closure is rolled into interlocking relationship with the flanged reinforcing strip. As a result, the edge of the container is compressed between the rigid xein-forcing strip and the end closure, causing it to act as a gasket. At the same time, the metal-to-metal contact between the reinforcing strip and the closure effectively eliminates "creep". By this procedure, sufficient strength is imparted to the container con-struction to permit the use of standard can openers to open the container.

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DETAILED DESCR P~ION OF THE INVENTION

The invention now will be described in greater _-detail with respect to the a~companying drawings wherein:
FIGURE 1 is an eIevational ~iew of a segment of ..
composite tubing with metal reinforcing bands bonded at spaced locations to its outer surface; ....
FIGURE 2 is an enlarged sectional view taken ~
along line 2-2 of Figure l; . .
FIGURE 3 is an enlarged sectional ~iew o~ a por- E
10 tion of the tubing shown in Figure 1 cut to container E
length; .-.
FIGURE 4 is an enlarged sectional ~iew of a seg- _ ment of the tubing shown in Figure 3; ~-FI.GURE 5 is an exploded sectional ~iew of a por-15 tion of a metal end closure and its relationship to L__ the segment of tubing shown in Figure 4 after the lat- ~.
ter has been flanged to receive the closure; ,-FIGURE 6 is a sectional view illustrating the in- F
terlocking relationship created between the portion of 20 metal end closure ana the segment of tubing shown in Figure 5 after they are brought together into operative -::
relationship; and FIGURE 7 is an eIevational view paxtially in -section, illustrating a completed container prior to 25 its being filled. ,.:

Referring to the drawings, Figure 1 illustrate~ ...
a length of composite fiber tubing 10 provided with metallic rein~orcing bands 12 integrally secured to the tubing at spaced locations along its length. The ~-.
spacing of the bands corresponds to the desired lengths 4 ~2~ 6 of the containers which are formed by cutting the tu~
ing alony the'circumferential centerlines of the bands. ' Details of a co~tainer body can be appreciated by reference to Figures 2-4. The container includes a multi-ply composite fiber wall 14 having strips 16 of the reinforcing bands 12 at its opposite ends. These '-strips are securely bonded to the outer surface of '-wall 10 by a suitable adhesive 1~.
The outer surface of the container can be labeled ~"' 10 prior to the affixing of the reinforcing bands 12 or ~-after installation o the strips, as indicated by the ~
numeral 20 in Figures 3 and 4. ~
To seal the interior wall of the containar, a _' lining 22 (illustrated in Figures 2-4~ is employed r"'_' which typically comprises a barrier layer of material having a low moisture'or vapor transmission xate, such as metallic foils, wax and synthetic polymers. The lining 22 is suitably laminated or adhered to the ex posed surface of the innermost composite fiber ply 14.
After the tubing 10 has been cut into lengths to ~:
form container bodies', the opposite ends of each body E
are flanged, as shown in Figures 5 and 7. The flanged r pcrtions fan out whe're the'tubing 10 has been cut, much liXe'the pages of an opened book, with the reinforcing ~-strip 16 being at the'outer edge of the flange. If desired, heat may be applied to the cut edges of the '~"
tubing to soften the reinforcing strips 16 and bonding agent 18 to facilitate the flanging operation.
Once the flanges have been formed, metal end clo- , 30 sures can be seated on the container bodies and inter- L
locked with the reinforcing strips 16 by a conventional can seamer. More particularly, a closure 24 is placed ~.2~ 39~

over the end of a container body (Figure 5) so that ~-its edge overlaps th~ flange. The closure then is t-rolled into contact with the flange such that the edge ,-of ~he closure pierces label 20 and engages the re-5 inforcing strip 16. Further rolling by the can seam- ~-er results in additional deformation of the closure -edge and the flange to produce a locking actio~ with the closure 24 in metal-to-me~al contact with strip 16 t-(Figure 6)~ The interlocking of closure 24 and strip ,::
10 16 produced by the seaming process, and the firm ~:
anchoring of strip 16 to container wall 14, results in ~-the anchorins of closure 24 to the container. ~~
As is apparent in Figure 6, after the seaming operat~on, the multi-ply wall 14 and liner 22 are r 15 compressed be~ween reinforcing strip 16 and the end closure 24 so as to form an air-tight sealing gasket.
To further improve the seal, a suitable seal nt ma- :
terial 26 may be applied to the end closure 24 prior -to placing the closure in engagement with the flange _ 20 at the end of the container body (Figure 5).
The container as it appears just prior to filling is shown in Figure 7. A~ter it is filled, the entire ~~
container is sealed by applying a further end closure in the same manner as previously described. r,, The support provided by the reinforcing strip 16 is the factor that enables the interior of the contain- -er to be maintained pressurized or partially evacuated :
through secure sealing of ths end closures 24 to the ' container. This holas true regardless of whether the 30 composite fiber wall construction is spirally or con- :
volutely wound, provided the following conditions are met: ~

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(1) that the reinforcing s~rips are of a ma terial having suitable strength and rigidity charac- -teristics; . -(23 that the strips are place.d so that the !-flanged wall portions of the container are compressed between the reinforcing strips and the ena closures; ~
and r_ (3) that thP deformation of the reinforcing strips so as to contact and overlap the edges of the closure is sufficient to prevent what is known as "creep".
By reinforcing the container wall with a rein- ' ~orcing strip, the seam formed when the end closura is secured to the container is given additional 15 strengtht thereby helping to support the seam when it --is opened by a conventional can opener which uses a ~-serrated wheel that rides along the seam to drive the r'~-cutting blade. The reinforcing strip also lends addi~ :
tional support to the container wall directly adjacent _ 2Q the seam. _ It should be noted that by reinforcing the flanged edge of the container wall, the flange is sufficiently supported to resist breakdown when moist-ened, as often occurs during liquid fill operations, -While the preferred embodiment of the invention has been described with respect to a composite fiber :
container, it will be understood that-the invention also may be incorporated in a container ~onstruction -in which the composite wall is a material suitably lined with an impervious metallic or plastic foil.

Claims (11)

WHAT IS CLAIMED IS:

1. A container construction comprising:
a composite wall;
a metallic reinforcing strip secure to and sur-rounding the exterior of the wall at each end thereof;
closures at the ends of the wall for sealing the container, said and closures each having an edge which engages a corresponding reinforcing strip and which deforms both the strip and a portion of the wall adja-cent the strip such that an edge of the strip overlaps the closure edge in interlocking relationship and the deformed portion of the wall is compressed between said strip and the closure.

2. A container construction as set forth in Claim 1 wherein both the reinforcing strips and the end closures are metallic whereby a metal-to-metal sealing relationship is achieved by engagement of the edges of the closures with the reinforcing strips.

3. A container construction as set forth in either of Claims 1 or 2 , wherein said wall comprises:
a barrier layer of substantially moisture- and vapoor-impervious material lining the interior of said wall.

4. A container construction as set forth in either of claims 1 or 2 wherein said wall comprises:
a barrier layer of substantially moisture-and vapor-impervious material lining the interior of said wall;
said wall comprising multiple plies of fiber.

5. A container construction as set forth in either of claims 1 or 2 wherein said wall comprises:
a barrier layer of substantially moisture-and vapor-impervious material lining the interior of said wall;
and wherein said wall comprises a polymeric material.

6. A container construction as set forth in either of Claims 1 or 2, wherein said wall comprises multiple plies of fiber.

7. A container construction as set forth in either of Claims 1 or 2, wherein said wall comprises a polymeric material.

8. A container construction as set forth in either of Claims 1 or 2, further comprising:
additional sealant means interposed between said wall and the end closures.

9. A container construction as set forth in either of claims 1 or 2 further comprising:
additional sealant means interposed between said wall and the end closures;
and wherein said wall comprises a barrier layer of substantially moisture-and vapor-impervious material lining the interior of said wall.

10. A container construction as set forth in either of claims 1 or 2 further comprising:
additional sealant means interposed between said wall and the end closures;
and wherein said wall comprises multiple plies of fiber.

11. A container construction as set forth in either of claims 1 or 2 further comprising:
additional sealant means interposed between said wall and the end closures;
and wherein said wall comprises a polymeric material.