Abstract: A base configuration for use with biaxially stretched blow molded PET containers is provided. In particular, the base includes a concave spherical portion disposed at a central position on the base. A first protruding circular member is formed around the circumference of the concave spherical portion. An annular groove is disposed around the first protruding circular member. A second protruding circular member is formed around the circumference of the annular groove. Five legs extend radially outward from the second protruding circular member. The outer surface of each leg subtends an angle of 72 degrees, and a curved rib is formed between every pair of legs, the ribs having an umbrella bone structure and each of the ribs subtending an angle of 0 degree, whereby the base of the container has an increased internal pressure resistance and thus prevents cracking in the base.

Abstract: A base configuration for use with biaxially stretched blow molded PET containers is provided. In particular, the base includes a concave spherical portion disposed at a central position on the base. A protruding annular member is formed around the circumference of the concave spherical portion, and five legs extend radially outward from the annular member. The outer surface of each leg subtends an angle ranging from 40-72 degrees, and a curved rib formed between every pair of legs, the rib subtending an angle ranging from 32-0 degrees, whereby the base of the container has an increased internal pressure resistance and thus prevents cracking in the base.