Method of extrusion blow-molding container having upper and lower sections of different thickness

DETAILED DESCRIPTION Reference will now be made in detail to the preferred embodiment of the present invention, several examples of which are illustrated in the accompanying drawings.
Referring now to the drawings, particularly to FIG.
1, there is illustrated a container, generally designated 10, constructed in accordance with the present invention.
The container 10 includes lower and upper portions 12 and 14, respectively, preferably formed of a unitary one-piece plastic construction.
Container 1O also includes a bottom wall 16 (FIG.
6) which is also preferably formed unitarily with the lower and upper portions 12 and 14, respectively, of container 10.
Lower and upper portions 12 and 14, respectively, are also generally tubular in cross-section and the side walls thereof may have any desired cross-sectional shape, i.
e.
, circular, square, rectangular, etc.
, at any elevation along the height of the container.
It is a particular feature of the present invention that the lower and upper portions 12 and 14, respectively, of container 10 are formed integrally of a plastic material having different thicknesses.
In a preferred form of the present invention and as best illustrated in FIG.
4, the lower portion 12 has side walls formed of a plastic material having a wall thickness t1.
Thickness t1 is sufficient such that the side walls are self-supporting.
That is to say, the side walls of container 10 are sufficiently rigid or structural so that the container in its upright position is self-standing or self-supportable.
In this connection, where the side walls form the self supporting means, the base or bottom wall 16 can be of any thickness desired by the user, including being of the same thickness as upper portion 14.
Not only does this afford stability to the upstanding container 10, but also provides a container which is relatively puncture-proof, has sufficient self or structural rigidity to retain its shape as a container, and is leakproof.
Thus, the advantages and benefits which accrue to conventional containers formed of plastic material and which containers retain their shape, definition and integrity as a plastic container of predetermined configuration will likewise accrue to container 1O hereof