A preform 20 comprises a neck portion 22 having an opening 21, a cylindrical barrel portion 23, and a bottom portion 24 larger in diameter than the barrel portion 23, and has a corner portion 25 at a boundary between the barrel portion 23 and the bottom portion 24.

A container includes a body that at least partially defines a product storage region. The container further includes a neck that extends upwardly from the body and that has an opening that opens into the product storage region to allow filling of the product storage region with contents and discharge of those contents. The container further includes a floor and a heel. Some areas of the container have varying material distribution or wall thickness.

An injection moulded thermoplastic preform for blow moulding to form a container, the preform comprising a lower closed base portion, a hollow body portion, a hollow transition portion between the lower closed base portion and the hollow body portion, and an upper open end portion adjacent to an upper part of the hollow body portion, wherein the closed base portion comprises a central portion which extends over at least 50% of an internal radius of a lower end of the hollow body portion and is either substantially flat or has a shallow concave or convex internal curvature, and the transition portion comprises an upwardly and radially outwardly tapering portion extending away from the central portion to connect to the hollow body portion, the tapering portion being inclined at an angle of from 1 to 20 degrees to a longitudinal axis of the preform and the tapering portion increasing in thickness from the central portion to the hollow body portion. Also disclosed is a method of injection moulding the thermoplastic preform.

A container having varying material distribution or wall thickness is disclosed.

A preform 20 comprises a neck portion 22 having an opening 21, a cylindrical barrel portion 23, and a bottom portion 24 larger in diameter than the barrel portion 23, and has a corner portion 25 at a boundary between the barrel portion 23 and the bottom portion 24.

An injection moulded thermoplastic preform for blow moulding to form a container, the preform comprising a lower closed base portion, a hollow body portion, a hollow transition portion between the lower closed base portion and the hollow body portion, and an upper open end portion adjacent to an upper part of the hollow body portion, wherein the closed base portion comprises a central portion which extends over at least 50% of an internal radius of a lower end of the hollow body portion and is either substantially flat or has a shallow concave or convex internal curvature, and the transition portion comprises an upwardly and radially outwardly tapering portion extending away from the central portion to connect to the hollow body portion, the tapering portion being inclined at an angle of from 1 to 20 degrees to a longitudinal axis of the preform and the tapering portion increasing in thickness from the central portion to the hollow body portion. Also disclosed is a method of injection moulding the thermoplastic preform.