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

A method for making a polymer vial by injection stretch blow molding, the method comprising:

• a. providing a mold, the mold comprising a first mold part, a second mold part, and a base mold, wherein the first mold part and the second mold part are 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 the second mold part mirror each other, wherein the base mold comprises a substantially flat molding surface and is configured to form a base of the vial, the first mold part, the second mold part, and the 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 the second mold part, wherein the base mold is axially distal to a location of the base mold when the mold is in the blowing position;
• C. moving the base mold axially towards the first mold part and the 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 mold cavity and conforms to respective surfaces of the first mold part, the second mold part, and the base mold when the mold is in the blowing position, wherein the substantially flat molding surface of the base mold is positioned entirely axially below respective molding surfaces of the first mold part and second mold part,
• wherein each of the first mold part and the 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 and the second curved mold surface following a radius with an imaginary center positioned outside the mold cavity.

A method for making a polymer vial by injection stretch blow molding, the method comprising:

• a. providing a mold, the mold comprising a first mold part and a second mold part, the first mold part and the 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 the 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, the second mold part, and the 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, wherein neither the first mold part nor the second mold part form any of the base of the vial, and the base mold forms no part of the sidewall 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 a location of the base mold 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 mold cavity and conforms to respective surfaces of the first mold part, the second mold part, and the base mold when the mold is in the blowing position, wherein the substantially flat molding surface of the base mold is positioned entirely axially below respective molding surfaces of the first mold part and the second mold part,
• 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.

A method for making a polymer vial by injection stretch blow molding, the method comprising:

• a. providing a mold, the mold comprising a first mold part and a second mold part, the first mold part and the 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 the 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, the second mold part, and the 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, wherein each of the first mold part and the 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 and the second curved mold surface following a radius with an imaginary center positioned outside the mold cavity, wherein no portion of the substantially flat molding surface of the base mold extends axially above the second curved mold surface;
• 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 a location of the base mold 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 mold cavity and conforms to respective surfaces of the first mold part, the second mold part, and the base mold when the mold is in the blowing position, wherein the substantially flat molding surface of the base mold is positioned entirely axially below respective molding surfaces of the first mold part and the second mold part,
• 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.