Abstract: Apparatus for forming a disc envelope from a prepunched, flexible, plastic blank having two sections connected at the heads thereof and containing a drive hole at the same location in each section. The drive holes are located on respective hubs which are located at the same position on respective folding plates. The end edge of a mandrel is pressed against the blank in the area between the two sections while the folding plates are moved from a horizontal to a vertical position pulling the drive holes taut on the hubs and thereby locating the center fold between the two sections of the blank flap folding apparatus and sealing apparatus are attached to and swing into operating position with the respective folding plates to form the side flap folds and seal the folded flaps.