Container

Abstract

A plastic container is described for liquids which are in part capable of migrating through the plastic. The container has a relatively rigid top and bottom connected by plurality of relatively narrow walls and a plurality of relatively wide wall located between the narrow walls. The wide walls are initially planar but assume a concaved configuration as the pressure in the container is reduced due to migration of moisture through the walls of the container, while the narrow walls rigid top and bottom remain unchanged in configuration.

Description

The invention is directed to plastic containers for liquids. More particularly the invention is directed to containers for liquids in which at least a part of the liquid tends to migrate through the walls of the container causing a reduced internal pressure that tends to collapse the container under the ambient pressure. The present invention makes use of the tendency of the container to reduce in volume during storage to produce a container the appearance of which is enhanced by volume reduction.

The advent of the form-fill-seal packaging which has resulted from the invention described in U.S. Pat. No. 3,325,860 has resulted in the production of low cost, filled and sealed sterilized materials. However, it has been found that many liquids when stored in plastic containers tend to have a portion of the liquid migrate through the walls of the container.

Depending upon the plastic material utilized, differential permeation may occur where a corresponding equal volume of gas cannot enter the container to replace the escaping liquid. This condition can be further aggravated because the container does not have a standard separate closure system which could function as a pressure equalizing vent. This results in a reduced volume and a reduced pressure in the container. The pressure differential between the ambient and internal pressures causes the container to collapse, or occupy less volume, and present an unpleasant appearance on extended storage.

It is an object of the present invention to provide a container for liquids subject to moisture migration in which the appearance of the package is enhanced upon storage.

It is another object of the present invention to provide a container for liquids subject to moisture migration which limits the volume reduction of the container to selected areas.

It is a further object of the present invention to provide a container for liquids subject to moisture migration in which most of the surface of the container is resistant to flexing and a portion of the surface of the container is subject to flexing.

It is still another object of the present invention to provide a container for liquids subject to moisture migration in which pre-selected portions of the package are adapted to assume a concaved position due to pressure differentials arising during extended storage.

Other and further objects of the invention will be apparent from reading the following description in conjunction with the drawings in which:

FIG. 1 is a front elevational view, partly in section, of a container embodying the present invention;

FIG. 2 is a side elevational view, partly in section, of the container of FIG. 1;

FIG. 3 is a top plan view of the container of FIG. 1;

FIG. 4 is a cross-sectional view taken generally along line 4--4 of FIG. 3;

FIG. 5 is a cross-sectional view taken across the length of the container of FIG. 1 showing a new configuration occupying less volume;

FIG. 6 is a cross-sectional view taken across the width of the container of FIG. 1 showing a smaller volume configuration; and

FIG. 7 is a cross-sectional view taken generally along line 7--7 of FIG. 5.

The objects of the present invention may be achieved in a plastic container for liquids which are, at least in part, capable of migrating through the plastic in which the container has a relatively rigid top and bottom joined by a plurality of relatively narrow wall portions and a plurality of relatively wide wall portions spaced between the relatively narrow wall portions.

As may be seen in FIG. 1, the container 10 is made up of a relatively rigid top portion 12 that is further comprised of a rounded shoulder portion 14, a planar portion 16, a neck portion 18 and an integral closure 20. It is advantageous that the neck 18 contain threads 22 which will cooperate with a dispensing device after the closure 20 is removed. A specific dispensing device contemplated is a baby nipple which typically has a soft pliable nipple connected to a container by a threaded ferrule.

The container 10 is further comprised of a relatively rigid bottom portion 24 which has a central portion 26 surrounded by an arcuate outer portion 28. The top portion 12 is joined to the bottom portion 24 by a plurality of relatively narrow walls 30, 32, 34, 36 and by a plurality of relatively wide walls 38, 40, 42, and 44. For esthetic reasons it has been found desirable that the walls 42, 44 be even wider than the walls 38, 40. Each of the wide walls is connected between two narrow walls as may be seen in FIG. 3.

In an especially advantageous embodiment the narrow walls have a dimension A which is about 1/2 inch and two of the wide walls have a dimension B which is about 1 inch while the remaining two wide walls have a dimension C which is about 1 1/4 inch. The total height of the widest walls as shown in dimension D (FIG. 1) is about 2 inches.

The liquid contents 46 are contained within the chamber 48 defined by the container.

As may be seen in FIGS. 1-4, in the container as initially filled the relatively wide walls are planar, that is, they are straight and undeformed.

After the container 10 has been stored for a period of time, which may be two weeks to two years, a portion of the liquid contents 46 has migrated through the walls and escaped the container. The resulting reduction in volume reduces the pressure within the chamber 48. This causes a differential pressure between the chamber 48 and the ambient atmosphere. Due to the pressure thus applied the relatively wide walls 38, 40, 42, 44 become concaved as is shown in FIGS. 5, 6 and 7. The narrow walls 30, 32, 34, 36 and the top portion 12 and the bottom portion 24 are less susceptible to deformation and show no visible deformation during the normal shelf life of the liquid contents.

The resulting package with the concaved wide walls presents a pleasing appearance. There is no deformation apparent to the consumer. Thus, by controlling the location of deformation the phenomenon of moisture migration may be utilized to enhance the container appearance during storage.

Claims

What is claimed is:

1. A sealed plastic container for liquids at least a portion of which is capable of migrating through the plastic comprising:

1. A relatively rigid top;

2. A relatively rigid bottom;

3. At least four relatively narrow, substantially planar wall portions connecting said top and bottom;

4. At least four relatively wide, substantially planar wall portions connecting said top and bottom and connected one between each pair of relatively narrow wall portions,

A. the width of said wide wall portions being about two to two and one half times the width of said narrow wall portions;

5. A liquid disposed within the container;

6. Said top, bottom and walls being formed from a plastic which is permeable by said liquid;

whereby the relatively wide wall portions become concaved when the liquid migrates through the plastic and the internal pressure becomes less than the ambient pressure while the relatively narrow wall portions, top and bottom, retain their initial shape.

2. A container as defined in claim 1 in which the height of the widest wall portions is about four times the width of said narrow wall portions.