Patent ID: 8733621

Claim:
A method of manufacturing a container of paper material, in particular for foodstuffs, the container comprising a sheet portion of flexible material defining a substantially flat bottom wall ( 2 ) and a side wall ( 3 ) emerging from said bottom wall ( 2 ), said bottom wall ( 2 ) and side wall ( 3 ) forming a cavity ( 7 ) with an upwardly facing opening in the normal use position of the container, the side wall ( 3 ) in the use condition of the container being confined at the lower part thereof by the bottom wall ( 2 ) and at the upper part by an edge ( 8 ) defining a contour of the cavity opening ( 7 ), the side wall ( 3 ) in section along a plane substantially perpendicular to the bottom wall ( 2 ) being defined by a stretch ( 9 ) joining said bottom wall to the opening contour, the method comprising the steps of: making said bottom wall ( 2 ) provided with an upper surface ( 2 a ) and a lower surface ( 2 b ) opposite to each other; making said side wall ( 3 ) emerging from the bottom wall ( 2 ) and defining, in cooperation with the bottom wall ( 2 ), a holding region ( 21 ) whose bottom is defined by said lower surface ( 2 b ), characterised in that it further comprises the following step: overturning the side wall ( 3 ) on the opposite side relative to the bottom wall ( 2 ) for defining a cavity having an upwards facing opening ( 7 ) in the normal use position of the container, said cavity having a bottom defined by said upper surface ( 2 a ); characterised in that said step of making said side wall ( 3 ) comprises a sub-step of making said stretch ( 9 ) joining said bottom wall ( 2 ) to a contour ( 22 ) of the holding region ( 21 ) in such a manner that the stretch ( 9 ) has at least one curved portion ( 10 a ) before the overturning step.