Patent ID: 7296701

Claim:
A bottle-shaped synthetic resin container comprising a body portion, and a circumferential groove extending along an outer surface of the body portion, said circumferential groove being defined by a groove bottom wall and groove side walls extending from the groove bottom to the outer surface of the body portion, both groove side walls of said circumferential groove are arranged opposite to each other and extend substantially linearly in a longitudinal-sectional plane including a center axis of the body portion, said groove side walls forming angles relative to a reference line that is perpendicular to the center axis in said longitudinal-sectional plane, the sum of which is not more than 30°, and said circumferential groove has a groove width and a groove depth, said groove width being smaller than said groove depth, wherein the angle sum, groove depth and groove width are selected such that upon enhanced contraction deformation of the container in the center axis direction, upper and lower edges of the circumferential groove are brought into contact with each other to preserve buckling strength and pressure reduction resistance.