Pressurized refill container resistant to sprue cracking

A refillable plastic container for pressurized applications able to withstand at least 10 refill cycles including a caustic wash at a temperature of at least 60.degree. C. and subsequent filling with a pressurized liquid at 4.0 atmospheres without crack failure, the container comprising:

• a body having a substantially transparent biaxially-oriented sidewall, the body further including a base having a standing ring around a push-up dome with a dome center adjacent a central axis of the container, and the dome having an outwardly concave exterior surface that extends from the standing ring and continues adjacent the central axis without an outwardly convex dish in order to prevent sprue cracking in the dome of the container, wherein the base has a wall thickness defined by a ratio of the thickness of the dome center (T.sub.s) to the thickness of the standing ring (T.sub.c) on the order of 1.4 to 1.9.

A refillable plastic container for pressurized applications able to withstand at least 10 refill cycles including a caustic wash at a temperature of at least 60.degree. C. and subsequent filling with a pressurized liquid at 4.0 atmospheres without crack failure, the container comprising:

• a body having a substantially transparent biaxially-oriented sidewall, the body further including a base having a standing ring around a push-up dome with a dome center adjacent a central axis of the container, wherein an exterior gate is disposed at the central axis of the base, the dome having an outwardly concave exterior surface with a continuous downward slope that extends from the standing ring to the gate without an outwardly convex dish in order to prevent sprue cracking in the dome of the container.

A refillable plastic container for pressurized applications able to withstand at least 10 refill cycles including a caustic wash at a temperature of at least 60.degree. C. and subsequent filling with a pressurized liquid at 4.0 atmospheres without crack failure, the container comprising:

• a body having a substantially transparent biaxially-oriented sidewall, the body further including a base having a standing ring around a push-up dome with a dome center adjacent a central axis of the container, and the dome having an outwardly concave exterior surface that extends from the standing ring and continues adjacent the central axis without an outwardly convex dish in order to prevent sprue cracking in the dome of the container, wherein the dome and standing ring form a thickened base portion having an average crystallinity of no greater than about 10%, and the sidewall has an average crystallinity of about 15 to 25%.