GB1591247A

GB1591247A - Flexible collapsible container

Info

Publication number: GB1591247A
Application number: GB4741177A
Authority: GB
Original assignee: Baxter Travenol Laboratories Inc
Current assignee: Baxter International Inc
Priority date: 1976-12-16
Filing date: 1977-11-15
Publication date: 1981-06-17
Also published as: CA1079231A; AU3035377A; AU509344B2; DE2754120A1

Description

(54) FLEXIBLE, COLLAPSIBLE CONTAINER (71) We, BAXTER TRAVENOL LABORA TORIES INC., a Corporation organised and existing under the laws of the State of Delaware, United States of America, of One Baxter Parkway, Deerfield, Illinois 60015, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a flexible, collapsible container and is an improvement in or modification of the invention described in U.K. patent specification no. 1,517,360.

Containers which are made of flexible material, so that they can easily collapse upon draining to a residual volume which is a very small percentage of the original filled volume, find particular use in the area of parenteral solution administration. Also, these containers can be put to any other use, particularly those uses where the venting of air into the container as it is emptied is considered not to be desirable.

In Grosjean U.S. patent Number 3,595,441, a collapsible tubular container of square cross section is disclosed utilizing a relatively rigid shoulder at one end, and a base at the other, about which the remainder of the container collapses through the infolding of gussets similar to those found in a paper bag.

The container of the Grosjean patent shares the characteristic with many other collapsible containers in that it is difficult to ascertain how much solution has been administered from the container, which is of course important to know in the field of administration of parenteral solutions. Furthermore, the Grosjean container is very complex and is subject to malfunction, since in the region of each gusset, seven individual fold lines must all function as intended in order to obtain the desired folding results.

Added to the total of twenty-eight fold lines in the regions of the four gussets are three fold lines on each of the sides of the container, to permit the achievement of the inward folding structure, in the manner of a paper bag having double, opposed bottom ends, as shown in the drawings of the Grosjean patent.

It is sometimes desirable to have a flexible, collapsible container which, nevertheless, can stand up on a relatively rigid base while it is full. Furthermore, it is desirable to provide a structure having fewer fold lines, so that there is less chance that a failing fold line will interfere with the collapse of the container.

In accordance with this invention, there is provided a flexible blow-moulded plastics collapsible container for liquid, which is a modification of or improvement in the invention disclosed in U.K. patent specification no. 1517360, the container having a rela- tively rigid shoulder and neck portion at one end, a relatively rigid base at the other end, and a collapsible, flexible, tubular body portion between the said shoulder and base and integral therewith, the flexible body portion including in its original unstressed condition first and second pairs of gussets, said pairs being positioned respectively adjacent the shoulder and the base, the gussets of each pair being opposite each other, each gusset being generally triangular, each gusset of the first pair being defined by an elongate recess forming a fold line and positioned adjacent to and generally parallel to an edge of the shoulder and two lines of folding weakness extending towards the base from opposite ends of said elongate recess and converging to define an apex, each gusset of the second pair being defined by an elongate recess forming a fold line positioned adjacent to and generally parallel to an edge of the base and two lines of folding weakness extending towards the shoulder from oppo site ends of said recessed fold line and converging to define an apex, each of the gussets extending outwardly from the adjacent base or shoulder respectively. so that upon collapse of the flexible body portion on draining of the container, the gussets fold outwardly of the container from the shoulder and base respectively.

Accordingly, collapse of the container in an inverted position, as the contents are withdrawn, takes place first directly adjacent to the base, and thereafter progressively from the area of the base towards the shoulder.

culminating in the outward collapse of the gussets next to the shoulder and inward collapse of the remaining portions of the container. The container folds up about the inner surfaces of the shoulder and base to create a very small residual volume when based upon the original volume of the container.

Because of the progressive tail-to-head collapse of the container when held in inverted position, it becomes feasible to make a reasonably accurate determination of the amount of contents of the container which have been expended, which is particularly important when the container is a parenteral solution administration container or other medical liquid container. However, simultaneously with this, the container is capable of standing on its base while full, and also collapsing down to a residual volume which may be about five percent of its original volume.

Preferably, the shoulder and base of the container are generally oval in shape, but preferably with truncated ends, the gussets being positioned adjacent the longitudinal ends of the oval.

It is also contemplated that, optionally, the circumference of the tubular wall between the shoulder and base may increase in the direction of the base so that the container exhibits a tapered aspect.

Referring to the drawings, Fig. 1 is an elevational view, with parts broken away, of a container according to this invention, shown lying in a mold half used for manufacture of the container by blow molding.

Figure 2 is a plan view of the container of Figure 1 from the shoulder end.

Figure 3 is an elevational view of the container, rotated 90 about its longitudinal axis from the aspect shown in Figure 1, also showing the molds used to manufacture the containet.

Figure 4 is an elevational view of the container of Figures 1 through 3 in the condition of having its contents partially withdrawn, and the wall portion adjacent to the base being folded up.

Figure 5 is an elevational view similar to Figure 4, showing the substantially completely collapsed container after virtually all of the contents have been expelled Figure 6 is an elevational view similar to Figure 5, rotated 90 about the longitudinal axis, also showing the filled configuration of the container in phantom lines for comparison.

Figure 7 is an elevational view of an alternative embodiment of a container according to this invention.

Referring to Figures 1 to 3, container 10 is shown positioned in a blow mold half 12. As shown in Figure 3, mating mold half 14 is provided to enclose a parison which may then be blow molded to form container 10, using retractable blowing tube 16 (shown in the retracted position). Neck mold halves 18, 20, which may be separate, are also shown.

All of the mold halves are mounted on pistons for advancement and retraction as desired to receive the hot parison, to close around it, and to expel the completed, blowmolded container 10 in accordance with conventional technology.

Container 10 defines a generally flat, relatively rigid base 22 from which protrudes a hanger member 24. Hanger member 24 may be connected to base 22 by a thinned web portion 26 so that hanger member 24 can be easily folded into flat, parallel relation with base 22 when it is desired to stand the container up. Hanger member 24 may be integral with container 10, or may be separately added after manufacture.

At the other end of the container is defined a relatively rigid neck portion 28, through which the contents of the container may be inserted and withdrawn, and a relatively rigid shoulder portion 30.

Tubular wall 31, which is relatively flexible when compared with the relatively rigid base 22 and shoulder portion 30, extends between the peripheries of shoulder portion 30 and base 22 to form a sealed, flexible container.

The container is advantageously made from materials having a plastic flexural modulus of at least 60,000 according to the test of ASTM-D790 (secant modulus of elasticity), and preferably no more than about 250,000, for example medium and high density polyethylene, polypropylene, or copolymers thereof.

Opposed pairs of gusset portions are provided in tubular wall 31 adjacent both base 22 and shoulder 30. Gussets 32, adjacent base 22, are defined during the blow molding operation by appropriate channels and elevations defined in mold halves 12, 14. Each gusset 32 is bounded, adjacent the base 22, by a recessed, folded line 34 positioned adjacent to and in generally longitudinal relation to the adjacent truncated edge 36 of the generally oval base.

Each gusset 32 is also defined by a pair of lines of folding weakness 38 which join together in angular relationship to define an outwardly pointing apex 40, which points away from base 22. The lines of weakness 38 extend towards respective ends of their associated recessed, folded line 34 to define a generally triangular arrangement.

Recessed line 34 may be formed by a projection 42 in each mold half 12, 14 (Figure 1). Portion 36 of base 22, as well as lines of weakness 38, may be defined by mold halves 12, 14, using grooves defined in the mold halves, as particularly shown with respect to edge portion 36 in Figure 1. These groove portions may preferably define, in cross section, arcs in the mold halves having a circumferential length which is from forty to sixty percent greater than the direct width of such grooves. The result of this is that, as the plastics material of the container expands into the grooves in the mold, a thinning effect takes place so that the minimum wall thickness within the lines of folding weakness is preferably from about forty to seventy percent of the thickness of the container wall adjacent the lines of folding weakness. Accordingly, the folding characteristic of the container is focused, and the lines of folding weakness provide improved ease of folding when subjected to a low suction pressure, as may be encountered when the contents of the container are expelled through a parenteral solution administration set.

Each gusset 43 adjacent shoulder 30 is defined by a recessed, folded line 42a and lines of folding weakness 46 which join together in angular relationship to define an outwardly pointing apex 48, which points away from shoulder 30. The lines of weakness 46 extend towards respective ends of their associated, recessed folded line 42a to define a generally triangular arrangement.

Recessed, folded line 42a may be formed by a projection 50 in mold halves 12, 14, as shown in Figure 1, while truncated edge 44 of generally oval shoulder 30 may be formed by a groove in the mold halves as shown, with the result that the shoulder tips 44 are thinned in the manner of oval base edges 36 and form a line of flexing weakness. Lines of weakness 46 may also be formed by grooves in the mold halves, and thus thin as they expand into the grooves, forming the lines of flexing weakness.

If desired, longitudinal line of folding weakness 52 may also be formed in container 10 by a longitudinally positioned groove in the mold, into which the parison can expand and accordingly thin, as previously described for other lines of folding weakness.

As shown in Figure 3, gussets 32 define a roughly triangular shape with a pair of curved legs 38, the height 53 of the triangular gusset 32 in the direction of the longitudinal axis of the container being less than the height 55 of gusset 43, for example from three fourths to one half the length of height 55. Similarly, the length of line 34 may be less, for example, from three fourths to one half the corresponding length of line 42a.

Alternatively however, it is also contemplated that the various gussets may be of equal size, or that gussets 32 may even be larger than gussets 43. The relative sizes and dimensions of base 22 and shoulder 30 may also be varied as desired.

Referring to Figure 4, it is shown how the container collapses at its upper end in its position of use, which end is base 22.

Container 10 is shown to be hanging from its hanger 24, with a conventional closure 54 having been attached by heat or solvent sealing, or any other desired technique, to the neck portion 28. A conventional parenteral solution set 56 has penetrated one of the ports of closure 54, which may provide a sterile seal to the container until punctured for draining of the liquid inside of the container.

As the liquid is drained, the walls of the container fold inwardly about lines of weakness 58 extending about the edges of base 22 between gussets 32, which are made by appropriate grooves in molds 12, 14 for thinning of lines 58. Simultaneously therewith, the walls of the container which define gussets 32 fold outwardly (see the full lines of Figure 6), with this action being caused by the interaction of lines 38, 34 and 36, so that the container folds simultaneously inwardly and outwardly about base 22. As the container collapses, it is possible for the collapse to proceed progressively down the length of the container, so that the amount of liquid expended can be determined with quick examination.

As the container completes its emptying, lines of weakness 60, which may also be formed by appropriate grooves in mold halves 12, 14, permit both walls of the container to collapse inwardly about the inner surface of shoulder 30 as shown, for example, in Figure 5, to reduce the residual volume of the container. Simultaneously, gussets 43 fold outwardly, to facilitate the collapse with a reduced number of fold lines, as shown in the full lines of Figure 6.

As the container collapses, it shortens in length, as the walls adjacent the ends collapse inwardly and outwardly.

Accordingly, a container is provided which is capable of collapsing to a residual volume of about five percent or less of the original volume with only a gentle suction pressure exerted, for example, by the suction head of a column of parenteral solution in a set extending from the container to the patient. This remarkable advantage can be obtained even though the container is made out of a relatively stiff material, for example, polypropylene or copolymers of polyethyl ene and polypropylene, having an overall wall thickness at the collapsible tubular wall 31 of, preferably, about 0.01 to 0.018 inch, and having a wall thickness at shoulder 30 and base 22 of preferably about 0.02 to 0.03 inch. The lines of weakness is preferably approximately forty to seventy percent thinner than the adjacent walls, for example 0.005 to 0.007 inch at the thinnest. The thickness of the walls may be thinner adjacent the base 22 than adjacent the shoulder 30 to facilitate preferential collapse at the base area.

Referring to Figure 7, a modified container in accordance with this invention is shown which is identical with the previous embodiment in all characteristics except as otherwise described herein.

The container 62 comprises, as before, a neck portion 63, a relatively stiff shoulder portion 64, and relatively stiff base 66, which may be slightly concave in shape, in part to accomodate the folded hanger member 68, which can fold flat into the concave recess of base 68 along thinned line of weakness 70.

A chief distinction of container 62 from the prior embodiment of container 10 is that the tubular wall 72 extending from the shoulder to the base is generally uniform in cross-sectional circumference, and not of the increasing circumference from shoulder to base, as in the previous embodiment.

Gussets 74, 76 are provided, in which the height of generally triangular gussets 74 may once again be different from the height of the generally triangular gussets 76.

The initial collapse of the container generally takes place in the region of gussets 74 and base 66, followed by the progressive collapse from the base end toward the shoulder end, and the ultimate outward folding of gussets 76 and inward folding of line of weakness 78, to provide a collapsed container of a configuration essentially similar to the previous embodiment.

It is also contemplated that, as before, the relative dimensions of base 66 and shoulder portion 64 may be varied. For example, the width of shoulder portion 64, i.e. the minor axis of it generally oval shape, may be greater than the width of base 66. The respective lengths of shoulder portion 64 and base 66 may be identical or different, as desired.

WHAT WE CLAIM IS: 1. A'flexible blow moulded plastics collapsible container for liquid, which is a modification of or improvement in the invention disclosed in U.K. patent specification no. 1517360, the container having a relatively rigid shoulder and neck portion at one end, a relatively rigid base at the other end, and a collapsible, flexible, tubular body portion between the said shoulder and base and integral therewith, the flexible body portion including in its original unstressed condition first and second pairs of gussets, said pairs being positioned respectively adjacent the shoulder and the base, the gussets of each pair being opposite each other, each gusset being generally triangular, each gusset of the first pair being defined by an elongate recess forming a fold line and positioned adjacent to and generally parallel to an edge of the shoulder and two lines of folding weakness extending towards the base from opposite ends of said elongate recess and converging to define an apex, each gusset of the second pair being defined by an elongate recess forming a fold line positioned adjacent to and generally parallel to an edge of the base and two lines of folding weakness extending towards the shoulder from opposite ends of said recessed fold line and converging to define an apex, each of the gussets extending outwardly from the adjacent base or shoulder respectively, 50 that upon collapse of the flexible body portion on draining of the container, the gussets fold outwardly of the container from the shoulder and base respectively.

2. A flexible collapsible container according to claim 1 in which the shoulder and base are generally oval in shape, the gussets being positioned adjacent the ends of the major axes of the shoulder and base.

3. A flexible, collapsible container according to claim 1 or 2 in which the circumference of said tubular wall increases in the direction of the base.

4. A flexible, collapsible container according to claims 1, 2 or 3, in which the first gussets and the second gussets are differently sized.

5. A flexible, collapsible container according to any preceding claim in which the height of the first gussets in the direction of the longitudinal axis of the container is greater than the height of the second gussets.

6. A flexible, collapsible container according to any preceding claim in which the thickness of the flexible wall adjacent the first gussets is greater than the thickness of the flexible wall adjacent the second gussets.

7. A flexible, collapsible container according to any preceding claim in which the base is generally concave in shape; a hanger portion is attached to the base and is foldable whereby the hanger portion can be extended for hanging or be folded to lie flat in a recess formed by the concave base, to facilitate the ease of standing of the container on the base.

8. A flexible collapsible container according to any preceding claim in which the circumference of the tubular body portion is generally constant between the shoulder and neck portion and the base.

9. A flexible collapsible container according to any preceding claim in which the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ene and polypropylene, having an overall wall thickness at the collapsible tubular wall 31 of, preferably, about 0.01 to 0.018 inch, and having a wall thickness at shoulder 30 and base 22 of preferably about 0.02 to 0.03 inch. The lines of weakness is preferably approximately forty to seventy percent thinner than the adjacent walls, for example 0.005 to 0.007 inch at the thinnest. The thickness of the walls may be thinner adjacent the base 22 than adjacent the shoulder 30 to facilitate preferential collapse at the base area. Referring to Figure 7, a modified container in accordance with this invention is shown which is identical with the previous embodiment in all characteristics except as otherwise described herein. The container 62 comprises, as before, a neck portion 63, a relatively stiff shoulder portion 64, and relatively stiff base 66, which may be slightly concave in shape, in part to accomodate the folded hanger member 68, which can fold flat into the concave recess of base 68 along thinned line of weakness 70. A chief distinction of container 62 from the prior embodiment of container 10 is that the tubular wall 72 extending from the shoulder to the base is generally uniform in cross-sectional circumference, and not of the increasing circumference from shoulder to base, as in the previous embodiment. Gussets 74, 76 are provided, in which the height of generally triangular gussets 74 may once again be different from the height of the generally triangular gussets 76. The initial collapse of the container generally takes place in the region of gussets 74 and base 66, followed by the progressive collapse from the base end toward the shoulder end, and the ultimate outward folding of gussets 76 and inward folding of line of weakness 78, to provide a collapsed container of a configuration essentially similar to the previous embodiment. It is also contemplated that, as before, the relative dimensions of base 66 and shoulder portion 64 may be varied. For example, the width of shoulder portion 64, i.e. the minor axis of it generally oval shape, may be greater than the width of base 66. The respective lengths of shoulder portion 64 and base 66 may be identical or different, as desired. WHAT WE CLAIM IS:

1. A'flexible blow moulded plastics collapsible container for liquid, which is a modification of or improvement in the invention disclosed in U.K. patent specification no. 1517360, the container having a relatively rigid shoulder and neck portion at one end, a relatively rigid base at the other end, and a collapsible, flexible, tubular body portion between the said shoulder and base and integral therewith, the flexible body portion including in its original unstressed condition first and second pairs of gussets, said pairs being positioned respectively adjacent the shoulder and the base, the gussets of each pair being opposite each other, each gusset being generally triangular, each gusset of the first pair being defined by an elongate recess forming a fold line and positioned adjacent to and generally parallel to an edge of the shoulder and two lines of folding weakness extending towards the base from opposite ends of said elongate recess and converging to define an apex, each gusset of the second pair being defined by an elongate recess forming a fold line positioned adjacent to and generally parallel to an edge of the base and two lines of folding weakness extending towards the shoulder from opposite ends of said recessed fold line and converging to define an apex, each of the gussets extending outwardly from the adjacent base or shoulder respectively, 50 that upon collapse of the flexible body portion on draining of the container, the gussets fold outwardly of the container from the shoulder and base respectively.

body portion is free of additional, longitudinally-oriented lines of folding weakness adjacent the shoulder and base portions.

10. A flexible collapsible container according to any preceding claim in which the gussets do not extend the entire maximum width of the body portion.

11. A flexible blow-moulded plastics collapsible container constructed substantially as herein described in the accompanying drawings.