1. Field of the Invention
The present invention relates to a container for particulate material, and, more particularly, to such a container having a filling valve with an effective seal for containing the particulate material.
2. Description of the Prior Art
The prior art, as exemplified by U.S. Pat. Nos. 2,189,847, 3,216,647, 3,894,682 and 3,904,107 is cognizant of multiwall paper bags formed with a filling valve for the insertion of particulate material. Such an industrial bag is shown in U.S. Pat. No. 3,216,647 wherein a tube of thermoplastic film is collapsed after filling for sealing purposes.
A particular problem associated with the prior art devices is that of tearing of the thermoplastic film during the filling operation due to the weight of the contents as well as the separation of thermoplastic film from the adjacent portions of the bag.