Flexible bag having a convertible bottom, method and machine for manufacturing same

A process for manufacturing a bag made of flexible material whereby:

• a first strip of flexible material is unreeled as a continuous sheet extending in a longitudinal direction,
• a fold is made using a folding means on the first strip along a transversal folding crease to fold a first flap onto a second flap against an internal face of the first strip,
• the first flap and the second flap are brought together along their edges,
• the strip is cut using a first cutting means by a transversal cut to form a section before or after the folding of the flaps one onto the other with the section forming the bag,
• a cheek and a hem are formed on each edge of the flaps before folding and adhesive is applied to the hems at least over one length of the first or second flap on one seam face using application means,
• a crease marking line is marked on each of the first flap and the second flap such that the folding crease is between the crease marking lines,
• wherein the folding brings the hem on each edge against each other and by the seam face in such a way as to obtain bonding between the hems and to bring the first and the second flaps together along the edges by means of bellows formed by the cheeks,
• at least one reinforcement layer is unreeled and cut using a second cutting means to obtain a system with at least one reinforcement panel,
• a first application of adhesive is applied using the first adhesive application means at least one of the first strip and the system with at least one reinforcement panel,
• before folding, the first strip and the system with at least one reinforcement panel are bonded together on the internal face of the first strip with the first application of adhesive in such a way that the system with at least one reinforcement panel is situated between the first and second flaps, and
• wherein to form the system with at least one reinforcement panel, two reinforcement panels are successively cut and placed, one on the first flap and the other on the second flap leaving a gap between them at the folding crease.

A process for manufacturing a bag made of flexible material whereby:

• a first strip of flexible material is unreeled as a continuous sheet extending in a longitudinal direction,
• a fold is made using a folding means on the first strip along a transversal folding crease to fold a first flap onto a second flap against an internal face of the first strip,
• the first flap and the second flap are brought together along their edges,
• the strip is cut using a first cutting means by a transversal cut to form a section before or after the folding of the flaps one onto the other with the section forming the bag,
• a cheek and a hem are formed on each edge of the flaps before folding and adhesive is applied to the hems at least over one length of the first or second flap on one seam face using application means,
• a crease marking line is marked on each of the first flap and the second flap such that the folding crease is between the crease marking lines,
• wherein the folding brings the hem on each edge against each other and by the seam face in such a way as to obtain bonding between the hems and to bring the first and the second flaps together along the edges by means of bellows formed by the cheeks,
• at least one reinforcement layer is unreeled and cut using a second cutting means to obtain a system with at least one reinforcement panel,
• a first application of adhesive is applied using the first adhesive application means at least one of the first strip and the system with at least one reinforcement panel,
• before folding, the first strip and the system with at least one reinforcement panel are bonded together on the internal face of the first strip with the first application of adhesive in such a way that the system with at least one reinforcement panel is situated between the first and second flaps, and
• using a third adhesive application means to apply adhesive to each of the cheeks or to a central part of the flaps in corner areas such that after formation of the bag the corner areas of the central part of the flaps are between the folding crease and one of the crease marking lines on the flaps.

A process for manufacturing a bag made of flexible material, the process comprising:

• unreeling a first strip of flexible material as a continuous sheet extending in a longitudinal direction;
• folding a first flap of the first strip along a transversal folding crease onto a second flap of the first strip such that edges of the first flap and the second flap are brought together and the second flap is against an internal face of the first strip;
• marking a crease marking line on each of the first flap and the second flap such that the folding crease is between the crease marking lines;
• forming a cheek and a hem on each edge of the first flap and the second flap and applying a first adhesive to the hems at least over a face seam of the first flap or a face seam of the second flap before folding the first flap onto the second flap;
• applying a second adhesive to each of the cheeks or to one or more corner areas of a central part of the first flap and a central part of the second flap such that after formation of the bag the corner areas of the central part of the flaps are between the folding crease and one of the crease marking lines on the flaps;
• cutting the first strip along a transversal cut, before or after the folding of the flaps one onto the other, to form a section of the first strip that forms the bag;
• wherein the folding of the first flap onto the second flaps brings the hem on each edge against each other so that the flaps are bonded together at the seam face to which the first adhesive is applied and the cheeks form bellows between the first flap and the second flap along the edges;
• unreeling and cutting at least one reinforcement layer to form a system with at least one reinforcement panel;
• applying a third adhesive to at least one of the first strip and the system with at least one reinforcement panel;
• and
• bonding the system with at least one reinforcement panel on the internal face of the first strip with the third adhesive before folding the first flap onto the second flap such that the system with at least one reinforcement panel is on the first flap or the second flap.