Flexible pouch having an opening sleeve

1. A pouch comprising a flexible bag having an opening having an edge fastened to a first and a second opposite walls of a reinforcing sleeve projecting to the outside of the bag, the pouch being suitable for adopting a flat configuration in which said walls are situated one against the other, and a utilization configuration in which said walls form a channel that holds the opening open, the first wall presenting a first longitudinal end strip that projects laterally from the edge of the opening, while the second wall presents a sliding edge configured to slide against an inside face of said first longitudinal strip when the pouch is passing from its flat configuration to its utilization configuration.

2. A pouch as claimed in claim 1 , wherein the second wall presents an outwardly-directed lateral step at the base of the sliding edge.

3. A pouch as claimed in claim 1 , wherein the two walls are fastened together via their longitudinal edges respectively opposite from the first longitudinal strip and from the sliding edge.

4. A pouch as claimed in claim 1 , wherein the sleeve presents a segment inside the bag, which segment has spreader tabs formed in continuity respectively with each of the two walls and having free lateral ends suitable for spreading apart from each other in the utilization configuration of the pouch in order to space apart the opposite faces of the flexible bag.

5. A pouch as claimed in claim 1 , wherein, in a region remote from the opening, the bag presents a line of weakness suitable for being broken in order to form a tear that extends into the inside space of the bag.

6. A pouch as claimed in claim 1 , wherein a height by which the sleeve projects beyond the opening varies across a width of the sleeve between a minimum height measured in the vicinity of one of the lateral ends of the sleeve and a maximum height measured in the vicinity of the opposite lateral end.

7. A pouch as claimed in claim 6 , wherein the maximum height is measured in the vicinity of the lateral end of the sleeve where the first longitudinal end strip and the sliding edge are located.

8. A pouch as claimed in claim 6 , wherein when the pouch is in the flat configuration, the free edge of the sleeve opposite from the opening represents an S-shape.

9. A pouch as claimed in claim 1 , including means for holding the walls of the sleeve in their channel-forming shape.

10. A pouch as claimed in claim 1 , wherein the sleeve has two holder tongues carried respectively by the first and second walls of the sleeve on the side opposite from the opening of the pouch, each of the tongues presenting a free head that is separated from the wall that carries said tongue by a blocking slot.

11. A pouch as claimed in claim 1 , wherein the second wall presents a second longitudinal end strip that projects laterally from the edge of the opening, the sliding edge being formed on the second strip.

12. A pouch as claimed in claim 11 , wherein the second wall presents an outwardly-directed lateral step at the base of the sliding edge.

13. A pouch as claimed in claim 11 , wherein the sliding edge is inclined, at least in an initial segment close to the opening, in the direction that increases the width of the second wall on going away from the opening.

14. A pouch as claimed in claim 13 , wherein the second wall presents an outwardly-directed lateral step at the base of the sliding edge.