Polymer vials with substantially flat bottoms and injection stretch blow molding methods for making the same

A polymer vial made by an injection stretch blow molding method, the method comprising:

• a. providing a mold, the mold comprising a first mold part and a second mold part, the first mold part and second mold part being configured to meet along a central axis to form an outer shape of a sidewall of the vial, wherein respective interior sizes and configurations of the first mold part and second mold part mirror each other, the mold further comprising a base mold configured to form a base of the vial, the base mold having a substantially flat molding surface, wherein at least 80% of the molding surface of the base mold occupies a single plane, the first mold part, second mold part and base mold together defining a mold cavity when the mold is in a blowing position in which the base mold is in position relative to the first and second mold parts to form the base of the vial;
• b. providing a mandrel within the mold and a molten polymer preform onto the mandrel, stretching the preform with the mandrel to extend an end thereof past respective molding surfaces of the first mold part and second mold part, wherein the base mold is axially distal to the base mold location when the mold is in the blowing position;
• c. moving the base mold axially towards the first mold part and second mold part to place the mold in the blowing position;
• and
• d. blowing gas into the preform such that the preform expands within the molding space and conforms to respective surfaces of the first mold part, second mold part and the base mold, when the mold is in the blowing position, the substantially flat molding surface of the base mold being positioned entirely axially below respective molding surfaces of the first mold part and second mold part;
• wherein:
• neither the first mold part nor the second mold part form any of the base of the vial;
• the base mold forms no part of the sidewall of the vial;
• each of the first mold part and second mold part include a first curved mold surface that leads to a second curved mold surface, the first curved mold surface following a radius with an imaginary center positioned in the mold cavity, the second curved mold surface following a radius with an imaginary center positioned outside the mold cavity;
• and
• no portion of the substantially flat molding surface of the base mold extends axially above the second curved mold surface;
• the vial comprising a base having a base surface area, a sidewall extending up from the base, the base and sidewall defining an interior configured to house product, the sidewall narrowing at an upper section of the vial to form a neck leading to an opening that provides access to the interior, the vial being symmetrical about a central axis, a lower portion of the sidewall comprising a first surface that is outwardly curved along a first radius having an imaginary center positioned within the vial, wherein the base in its entirety is positioned below the first surface and is substantially flat such that at least 80% of the base surface area comprises a standing base surface occupying a single plane.

A polymer vial comprising a base having a base surface area, a sidewall extending up from the base, the base and sidewall defining an interior configured to house product, the sidewall narrowing at an upper section of the vial to form a neck leading to an opening that provides access to the interior, a lower portion of the sidewall comprising a first surface that is outwardly curved along a first radius having an imaginary center positioned within the vial, wherein the base is positioned below the first surface and is substantially flat such that at least 80% of the base surface area comprises a standing base surface occupying a single plane, the vi al further comprising a second surface that extends from and is positioned below the first surface, the second surface being inwardly curved along a second radius having an imaginary center positioned outside of the vial, the second surface terminating at a peripheral edge of the base from which the standing base surface extends inwardly towards a central axis of the vial, the standing base being configured to contact and rest on a flat support surface so as to orient the vial in an upright position, the standing base being completely flat with a possible exception of slight relief in a gate area, as an artifact of a molding process for making the vial, wherein the sidewall of the vial adjacent the base thereof has a thickness that is the same as, or less than, a thickness of the base of the vial.