Abstract: A container unit comprises an integrally formed container component (1) comprising a casing (20) and a closure (10), which includes a lid (11) initially sealed with an original seal (12) . A separate bottom piece (30) for the container is permanently secured to the casing (20) of the container component containing the product, preferably by rotation-friction welding the bottom piece and the casing, both of which consist of polypropene. The component (1) is oriented with the closure (10) facing down and the product is poured in via the open end of the casing. The bottom piece is then placed in the open end of the container casing and rotation-friction welded to the casing. A partition (36) may be inserted in the casing to define a space for the product corresponding to the volume of the product.