Double container

Abstract

A double container includes an inner container and an outer container, has a mouth portion, a body portion and a bottom portion disposed in this order from top to bottom along a direction of a bottle axis, and includes an outside air introduction hole. The bottom wall portion of the bottom portion includes a ground contact portion and a recessed portion. A peripheral wall portion of the depressed portion extends inward in a radial direction as it goes upward. A plurality of ridge portions protruding radially inward are provided on the peripheral wall portion of the depressed portion at intervals in a circumferential direction. The peripheral wall portion of the depressed portion or the ridge portion extends inward in the radial direction via a step portion as it goes upward.

1 . A double container comprising:
 an inner container which decreases in volume and deforms with decrease in contents therein; and   an outer container in which the inner container is installed,   wherein a mouth portion, a body portion, and a bottom portion are disposed in this order from top to bottom along a direction of a bottle axis,   the double container includes an outside air introduction hole which introduces outside air between the outer container and the inner container with decrease in the contents,   a bottom wall portion of the bottom portion includes   a ground contact portion located at an outer peripheral edge portion, and   a depressed portion having a cylindrical shape with a top, the depressed portion which is positioned inside the ground contact portion in a radial direction and recessed upward,   a peripheral wall portion of the depressed portion extends inward in the radial direction as it goes upward,   a plurality of ridge portions protruding inward in the radial direction are provided on the peripheral wall portion of the depressed portion at intervals in a circumferential direction, and   the peripheral wall portion of the depressed portion or the plurality of ridge portions extend inward in the radial direction via a step portion as it goes upward.   
     
     
         2 . The double container according to  claim 1 ,
 wherein the peripheral wall portion of the depressed portion extends inward in the radial direction via the step portion as it goes upward, and   the plurality of ridge portions which protrude inward in the radial direction and divide the step portion in the circumferential direction are provided on the peripheral wall portion of the depressed portion at intervals in the circumferential direction.   
     
     
         3 . The double container according to  claim 2 ,
 wherein upper and lower surfaces of a ceiling wall portion of the depressed portion are flat surfaces.   
     
     
         4 . The double container according to  claim 2 ,
 wherein in a wall portion which defines the plurality of ridge portions, a top wall facing the radial direction is positioned inside the step portion in the radial direction.   
     
     
         5 . The double container according to  claim 1 ,
 wherein the plurality of ridge portions extend inward in the radial direction via the step portion as it goes upward.   
     
     
         6 . The double container according to  claim 5 ,
 wherein upper and lower surfaces of a ceiling wall portion of the depressed portion are flat surfaces.   
     
     
         7 . The double container according to  claim 5 ,
 wherein the step portion is positioned inside the peripheral wall portion of the depressed portion in the radial direction.   
     
     
         8 . The double container according to  claim 1 ,
 wherein the body portion has a narrowed portion, the narrowed portion which extends inward in the radial direction from an outside to an inside along a direction of a bottle axis, and which is formed to be elastically deformable,   the narrowed portion is formed by connecting a concave curved surface portion and a convex curved surface portion in this order from top to bottom without a step, the concave curved surface portion which is recessed inward in the radial direction, and the convex curved surface portion which bulges outward in the radial direction, and   in a vertical cross-sectional view along the direction of the bottle axis, a difference between a radius of curvature of the concave curved surface portion and a radius of curvature of the convex curved surface portion is 20% or less with respect to a larger one of the radii of curvature.   
     
     
         9 . The double container according to  claim 8 , wherein the radius of curvature of the concave curved surface portion is greater than the radius of curvature of the convex curved surface portion in the vertical cross-sectional view. 
     
     
         10 . The double container according to  claim 8 , wherein a vertical reinforcement groove extending in the direction of the bottle axis is formed in the convex curved surface portion.