Method of forming container with high-crystallinity sidewall and low-crystallinity base
AssigneeContinental PET Technologies, Inc.
InventorsWayne N. Collette, Suppayan M. Krishnakumar, Chi Ching Lin
Life of this patent
Estimating the term…
Abstract
A method of making a polyester container having an enhanced level of crystallinity in the sidewall while maintaining a low level of crystallinity in a thickened base portion. The container is particularly useful as a refillable container which can withstand higher caustic wash temperatures and exhibits reduced flavor carryover, or as a hot-fill container. According to the method, a sidewall-forming section of a preform is initially expanded, heated to contract and crystallize the same, and than reexpanded; a base-forming portion of the preform is shielded from the heat treatment and is expanded either before or after the heat treatment step.
Claims25
A container comprising a substantially transparent, biaxially-oriented, free-standing, blow-molded polyester body, the body having a sidewall, with an upper tapered shoulder and a substantially cylindrical panel, and a base, the base being a champagne base having a thickened base portion comprising a central dome and a chime, the thickened base portion having with a wall thickness at least about 3× greater than a thickness of the panel, the panel having an average crystallinity of at least 35% and the thickened base portion having an average crystallinity of no greater than about 10%.
Dependencies are inferred from the claim text.