Abstract: An improved easy opening pinch bottom or gusset bag is provided. The bag includes opposed front and back panels and opposed pairs of front and rear gusset panels foldably connected to one another. The rear gusset panels and the rear panel are of a sufficient dimension to fold over the front panel to close the bag. A tear strip is secured to the front panel at a location to be overlapped by the rear gusset panels and the rear panel when the bag is closed. The portions of the rear gusset panels and the rear panel that will lie adjacent the tear strip in the closed condition of the bag are provided with short perforation lines to facilitate the initial advancement of the tear strip through the rear gusset panels and the rear panel. These perforation lines extend only a short distance so that the overall strength of the bag is not adversely affected.

Abstract: Heat transfer paper is provided having applied to at least one surface thereof from about 1/2 to 5 pounds per side of a high-volume, liquid swellable material selected from the group consisting of clays and starches.

Abstract: Tearing, blistering, delamination and other defects in deep drawn plastic laminated paperboard containers are eliminated by adding controlled amounts of warmed moisture to the paperboard immediately prior to forming thereof. Water is heated to a desired temperature and is applied by in-line processing equipment to the unlaminated side of the paperboard which functions to both soften and paperboard and preheat the laminate. By heating both the male and female parts of a die press employed for forming the preheated, softened laminate into the container, preheating the laminate using warm water prior to forming and, continuously controlling the moisture added to the paperboard, the degree of stress imposed on the plastic layer of the laminate and the resulting defects in the formed container are significantly reduced.