Bag and related methods

A bag comprising:

• a front panel and back panel sealed at a base of the bag and two sides extending from the base to define a containment region, the bag being open or openable at an opening region opposite the base and where a multi-panel assembly is provided comprised of
• said front panel and back panel,
• at least one side being of a gusset formation,
• a first closure panel comprising a closure element having a base at one face of the first closure panel, the closure element being configured for cooperating with a closure element associated with the back panel to provide an openable and re-closable closure of the containment region, the first closure panel having another face opposite the one face that is bondable to the front panel, and
• a non-bonding zone located on the one face of the closure panel between the one face of the first closure panel and the back panel, or located on the front panel between the one face of the first closure panel and the back panel, at which the back panel and the one face of the first closure panel are prevented from bonding to each other directly under an application of heat and pressure, the non-bonding zone extending along the length of the openable and re-closable closure, and more distal of the base of the bag than the openable and re-closable closure,
• wherein in a first mode the first closure panel is associated with the back panel, and the containment region is accessible through a first mode opening the perimeter of which is defined by the front panel and back panel and two sides, and
• wherein in a second mode, following an application of heat and pressure along the non-bonding zone to the back panel, the first closure panel, and the front panel of the multi-panel assembly, the first closure panel is bonded to the front panel and the back panel of the multi-panel assembly to define a removable header comprised of a portion of the front and the back panels, and a void in which the non-bonding zone resides, the removable header being located at a position more distal from the base than the non-bonding zone, and the void being defined by two unconnected pieces with substantially abutting adjacent edges to define a line of weakness at the void along which the multi-panel assembly is tearable to remove the header, such that a second mode opening to the containment region is able to be created between the closure element of the back panel and the closure element of the first closure panel to provide access to the openable and re-closable closure of the containment region, and the perimeter of the second mode opening that allows access to the containment region is defined by and between the two closure elements, and
• wherein each panel comprises multiple plies, the multiple plies comprise at least a first ply and a second ply, wherein the second ply is less stretchable than the first ply, and the first ply is bondable to another panel of the multi-panel assembly under an application of heat and pressure.