| 摘要 |
A preform injection molded from PET includes a frustoconical section whose outer surface is formed with a series of angularly spaced ribs. When the preform is converted into a bottle by a blow molding operation, the frustoconical section of the preform is converted to a frustoconical top breast for the bottle while the external ribs of the preform are converted into internal ribs which are spaced angularly around the inner side of the top breast to increase the column strength thereof. |
