Easy-open composite containers for packaging various products, particularly products under pressure such as refrigerated dough products and the like, constitute a significant commercial consumer product. Typically, these containers are formed of a spirally-wound paperboard or board stock bodywall layer and an interior liner layer for preventing leaking of the contents from the container. The spirally-wound bodywall layer usually includes a butt joint formed by adjacent edges of the bodywall layer and which forms a spiral seam extending from one end of the container to the other end. The exterior label layer surrounds the bodywall layer and covers or bridges the spiral seam to reinforce such seam and prevent premature opening along the spiral seam.
Commercially significant containers of this type are disclosed in commonly assigned U.S. Pat. No. 3,981,433 which is directed to a one-step easy-open container including an inner liner layer, a bodywall layer and an outer label layer, all of which are spirally-wound to form a spiral easy-open seam in the bodywall layer. In this type of container, when the outer label layer is either totally removed or that portion bridging the spiral butt joint of the bodywall layer is torn away from the spiral seam, the pressurized dough products expands outwardly and causes the spiral seam of the bodywall layer to open. This allows access to the dough and the interior of the container through the spiral easy-open seam in the container.
The outer label layer surrounding the spiral seam in containers of this type is an important structural component of the container because the outer label layer bridges the spiral seam and maintains it in closed position. Accordingly, in order to easy-open the container, that portion of the label layer which bridges the easy-open spiral seam of the bodywall layer must be stripped away to expose the spiral seam for easy-opening. Alternatively, the label layer may be totally peeled away from and removed from the bodywall layer of the container. This is desirable if a coupon or other advertising material is positioned under the label layer for removal by the purchaser of the container when opening of the container.
Various mechanisms have been provided to aid in such easy-opening including provision of a tear tab for starting the peeling or removal of the label layer so that the label layer may be torn toward a "collar cut" extending around the periphery of the label layer near one end of the container for completely removing the label layer from the bodywall layer during easy-opening. Also, tear strips have been provided between the label layer and the bodywall layer in bridging relation to the easy-open spiral seam of the bodywall layer to act as a tearing medium for tearing away that portion of the label layer which bridges the easy-open spiral seam of the bodywall layer. However, with both procedures for removing the label layer from the spiral easy-open seam of the bodywall layer, tearing of the label layer in a desired direction has created problems and often such tearing does not accomplish the desired purpose of either removing the entire label layer or just a bridging portion of the label layer from the spiral seam of the bodywall layer for easy-opening of the container. Tearing is also affected by the direction of pulling or tear pressure applied by the user which is sometimes dictated by being right-handed or left-handed or by having the container in an upright position or in an upside-down position.