Patent ID: 8435027

Claim:
A preform molding apparatus for forming a preform having a neck ring, a mouth neck part and a body part, comprising: a preform mold comprising: a mouth neck part mold having a first section for molding an outer surface of the mouth neck part, a second section for molding an upper surface and an outer-vertical surface of the neck ring, and a first sliding surface extending linearly downwardly from a portion of the second section defining the outer-vertical surface, a body part mold having a third section for molding an outer surface of the body part, a fourth section for molding an entire lower surface of the neck ring, and a second sliding surface extending linearly downwardly from an outer edge of the fourth section and slidably contacting with the first sliding surface, and a core mold for molding an inner surface of the preform, wherein when a molten resin material is solidified and shrunk, the mouth neck part mold and the body part mold move relative to each other according to an amount of shrinkage of the molten resin material while sliding at the first and second sliding surfaces to thereby mold the neck ring.