Tubular container with invisible longitudinal overlapped side seam

A process of forming a laminate tube with an invisible longitudinal overlapped seam, comprising:

• overlap welding a first edge of one margin of a laminate sheet comprising an outer plastic layer, a barrier layer, and an inner plastic layer of the same material as the outer plastic layer to a second edge of an opposite margin of the laminate sheet, each of the first and second edges being cut obliquely at a predetermined angle of 30° up to, but not including, 90° before welding and the welding being performed in an overlapped region with an outer surface of the outer plastic layer at the second edge directly contacting and overlapping both the obliquely cut first edge and an outer surface of the inner plastic layer at the first edge such that an inner surface of the laminate tube has a hump in the overlapped region, while an outer surface of the laminate tube is smooth without a hump in the overlapped region.