Container having rectangular base and its manufacturing

A process for the manufacture of a container, the container having a generally rectangular base and walls extending therefrom, the base being made of a first laminated film having an inner face and an outer face, with both of said faces being heat weldable, and the walls being made of a second laminated film having an inner face and an outer face, with only said inner face of said second laminated film forming said walls being heat weldable, the process comprising:

• (a) constructing said container from a front sheet having a bottom edge and lateral edges, a rear sheet having a bottom edge and lateral edges, and a bottom sheet, the bottom sheet being folded along a midline thereof with first and second flaps extending downwards from the midline, said flaps each having a bottom edge and lateral edges, and wherein the bottom edge of the first flap is joined to the bottom edge of the front sheet and the bottom edge of the second flap is joined to the bottom edge of the rear sheet;
• and welding lateral edges of the front and rear sheets to one another with bottom portions of the lateral edges of the front and rear sheets sandwiching corresponding lateral edges of the first and second flaps;
• (b) unfolding the bottom sheet such that a central portion of the sheet assumes a rectangular shape and two peripheral portions of the bottom sheet form two overlapping triangular portions;
• and
• (c) welding the two overlapping triangular portions to one another and welding a peripheral triangular portion of the two triangular portions with a juxtaposed inner face of a correspondingly juxtaposed front and rear sheet.

A container having a rectangular base formed out of a first laminated film sheet having an inner and an outer face, and a front, a back and two side walls formed out of two second laminated film sheets, said two second laminated film sheets each being welded to one another along side edges thereof and sandwiching therebetween at a bottom portion, corresponding side edges of said first laminated film sheet which is folded downward about a midline thereof in a direction transverse to said side edges of said first laminated film sheet;

• a bottom edge of each of said two second laminated film sheets being welded to a corresponding bottom edge of said folded first laminated film sheet;
• both an inner and an outer face of said first laminated film sheet, and only an inner face of each of said two second laminated film sheets being heat weldable;
• the container has at each side wall two overlapping triangular portions being formed during a forming step out of said first laminated film sheet with a base of each triangle defining a side edge of the container's base, whereby front and rear edges of the container's base extend between said side edges, said forming step being done by a mandrel being inserted into a space defined between said welded two second laminated film sheets, the mandrel opening said container by pressing said first laminated film sheet in a downward direction and pressing said two second laminated film sheets outwardly in two generally opposite directions orthogonal to the downward direction;
• the structure being fixed by welding the two overlapping triangular portions at each side wall to one another and to the adjacent corresponding portions of said two second laminated film sheets which become the side walls of the container.

A process for the manufacture of a container having a rectangular base, the process comprising:

• a. providing a laminated first film having a first and second side, the first side being heat weldable and the second side not being heat weldable, said first film having a transverse leading edge, a top edge, and a bottom edge;
• b. providing a laminated second film having a first and second side, the first side being heat weldable and the second side not being heat weldable, said second film having a transverse leading edge, a top edge, and a bottom edge;
• c. providing a laminated third film having a first and second side, both the first and second sides being heat weldable, said third film having a transverse leading edge, a top edge, and a bottom edge;
• d. folding said laminated third film in a longitudinal direction intermediate said top and bottom edges along a fold line so as to form a first flap and a second flap, such that said top and bottom edges of said laminated third film are juxtaposed each other, said first and second flaps being joined at one ends thereof at said fold line such that said bottom edge of said laminated third film becomes a bottom edge of said first flap, and said top edge of said laminated third film becomes a bottom edge of said second flap;
• e. placing said heat weldable first sides of said laminated first and second films facing each other with respective transverse leading, top, and bottom edges in corresponding mutual alignment;
• f. inserting said folded laminated third film between said laminated first and second films with said bottom edges of said first and second flaps in alignment with said bottom edges of said laminated first and second films so that said fold is oriented towards a middle portion of said first laminated film and oriented towards a middle portion of said second laminated film, and the transverse leading edge of said laminated third film is in corresponding mutual alignment with the leading edges of said laminated first and second films;
• g. in any order heat welding a bottom edge portion of said first flap to a bottom edge portion of said laminated first film;
• heat welding a bottom edge portion of said second flap to a bottom edge portion of said laminated second film;
• heat welding a first transverse portion of said laminated first film, which extends from said bottom edge to said top edge thereof, to a first transverse portion of said laminated second film, which extends from said bottom edge to said top edge thereof, including simultaneously heat welding a first transverse portion of said first flap and a first transverse portion of said second flap to each other and to bottom portions of said first transverse portions of said laminated first and second films;
• heat welding a second transverse portion of said laminated first film, which extends from said bottom edge to said top edge thereof, to a second transverse portion of said laminated second film, which extends from said bottom edge to said top edge thereof, including simultaneously heat welding a second transverse portion of said first flap and a second transverse portion of said second flap to each other and to bottom portions of said second transverse portions of said laminated first and second films;
• h. cutting off a section of said laminated first, second and third films along a transverse cut-line proximate to a position of a heat-weld disposed along said second transverse portions of each of said laminated first, second and third films, whereby a first edge of said cut corresponds to a trailing edge of a first container blank, and a second edge of said cut corresponds to a leading edge of a next container blank and thereby simultaneously becomes the leading edge of each of the laminated first, second and third films;
• i. drawing apart portions of the non-welded portions of said cut-off laminated first film section and said cut-off laminated second film section;
• j. inserting a mandrel having spreadable jaws between said drawn apart portions of said laminated first film and said laminated second film;
• k. spreading said jaws of said mandrel to spread apart said laminated first film and said laminated second film so as to form two sets of two triangular portions on each side thereof from said first and second flaps;
• l. heat welding each set of said triangular portions together at least along a bottom portion thereof, and heat welding each set of said triangular portions to juxtaposed first sides of said laminated first and second films;
• wherein step h can be performed in any order in relation to steps d-g;
• whereby a container having a flat rectangular bottom is formed.