Paperboard liquid container

Claim 1

A liquid impermeable prismatically shaped paperboard comprising four peripheral surface sheets and an adjacent piece which are disposed in a manner to be continuous in a lateral direction through fold lines; flaps forming a lid portion and a bottom portion respectively disposed in a manner to be contiguous to upper and lower edges of said peripheral surface sheets through fold lines; said lid flap having oblique fold lines therein, and tip pieces for joining extending from an outermost end thereof, said tip pieces being folded along fold lines extending therebetween thereby forming the lid portion in the shape of a roof; said bottom portion including outer bottom sheets and inner bottom sheets respectively opposing each other, tip pieces disposed at tips of the opposing bottom sheets of said container bottom portion, the opposing inner bottom sheets being formed with folds in the shape of isosceles triangles whose bases are the fold lines thereof, small pieces protruding outwardly beyond outer edges of said inner bottom sheets from central parts at which exist apexes of the isosceles-triangular folds; and said opposing inner bottom sheets being foldable inwardly, said small pieces being insertable between the two outer bottom sheets, said tip pieces of said opposing outer bottom sheets being placeable thereon, opening parts of said paperboard thereby being joinable in a manner not exposed to the interior of said container.