Preform for stretch blow-molded bottle

A preform for a plastic bottle produced by injection stretch blow molding, the preform comprising:

• a barrel section;
• a neck section continuous with an upper portion of the barrel section;
• and
• a bottom section continuous with a lower portion of the barrel section,
• said bottom section includes:
• a flat bottom surface central portion having a diameter d less than an inner diameter D of the barrel section and a thickness t2 less than a thickness t1 of the barrel section,
• a bottle bottom surface-forming portion formed by bending, at a height position h, a portion that forms a bottom edge of the bottle, the bottle bottom surface-forming portion extending to a circumference of the bottom surface central portion and including a bottle bottom edge-forming portion, and
• a curved portion interposed between a lower portion of the bottle bottom surface-forming portion and the bottom surface central portion,
• wherein the bottom section has an inverted truncated conical shape, wherein the bottle bottom surface-forming portion is continuous with the lower portion of the barrel section and inclined toward the bottom surface central portion,
• the bottle bottom edge-forming portion is an upper portion of the bottle bottom surface-forming portion and is continuous with the lower portion of the barrel section,
• an inner surface of the bottle bottom surface-forming portion is formed as a gently curved convex surface extending from a lower portion of the bottle bottom edge-forming portion to an upper portion of the curved portion such that a thickness t3 of the bottle bottom surface-forming portion is increased to be greater than the thickness t1 of the barrel section, and
• wherein the bottle bottom edge-forming portion is formed to have a thickness t4 less than the thickness t3 of the bottle bottom surface-forming portion.