Abstract: A single blank is used to make an expandable envelope construction having four side edges which can expand as the envelope construction is filled to capacity. The blank is provided with horizontal and vertical score lines and fold lines which permit the sides and bottom of the construction to collapse inwardly while the pocket enlarges in thickness and decreases in height and width. The blank has side flaps with corners at the ends which are overlaid by the back panel and closure panel in an unsecured manner to maintain the envelope in a sealed condition when expanded.

Abstract: The folder is made with a pair of sections, each of which is provided with an inside panel to form a pocket. The inside panel and the front panel of each section of the folder is provided with vertical and horizontal score lines adjacent the respective edges of the folder to permit expansion of the pockets when filled with paper or the like. The folder is also provided with a pair of score lines on opposite sides of the vertical fold line to allow the folder to triangulate along the vertical fold line when the folder is filled to capacity. When filled to capacity, the folder retains a flat appearance.