Preform for a monobase container

Abstract From the Canadian patent

An preform for blow molding a one-piece plastic container of the champagne base variety having an annular peripheral chime surrounding an inward sloping base portion for containing carbonated beverages. The preform defining interior and exterior walls which are ever decreasing in diameter from the neck to the base so that the preform may be easily removed from a mating core and injection mold cavity used therewith thereby avoiding the need for a split mold to form the preform. The preform including a thickened annulus adjacent the transition between sidewall and base forming portions thereof and an exterior weight reducing annular concavity between the thickened annulus and the closed end …