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A method for forming a leak free container, such as a paper cup, including a sidwall having a lap joint and a bottom wall connected to the sidewall by means of a bottom wall lap joint incorporating a portion of the sidewall lap joint wherein the method includes the step of applying caulking material

A method for forming a leak free container, such as a paper cup, including a sidwall having a lap joint and a bottom wall connected to the sidewall by means of a bottom wall lap joint incorporating a portion of the sidewall lap joint wherein the method includes the step of applying caulking material, at a predetermined location, to one of the blanks forming the bottom and sidewall which location is selected to insure sealing of any void volume formed adjacent the sidewall lap joint within the bottom wall lap joint. Preferably, the caulking material will be a hot melt adhesive and will be employed in a cup making process involving the use of polyethylene coated paper stock. Careful control of the temperature, amount, location and viscosity of the hot melt during the lap joint forming process and of the heat and temperature used in the lap joint forming steps insure that the hot melt material ends up residing in precisely the appropriate location within the void volume. Also disclosed are a variety of cup designs in which the void volume is reliably caulked by means of the disclosed method. In the preferred design, the caulking material is placed exclusively in the exterior leg of a U-shaped void volume.

대표청구항 ▼

A method for forming a leak free container from a sidewall blank and a bottom wall blank, comprising the steps of (a) joining together a pair of generally opposed edges of said sidewall blank in overlapping relationship to form a sidewall lap joint including an inner sidewall edge and an outer sidew

A method for forming a leak free container from a sidewall blank and a bottom wall blank, comprising the steps of (a) joining together a pair of generally opposed edges of said sidewall blank in overlapping relationship to form a sidewall lap joint including an inner sidewall edge and an outer sidewall edge, (b) joining the peripheral edge of said bottom wall to the bottom edge of said sidewall in overlapping relationship to form a bottom wall lap joint incorporating a portion of said sidewall lap joint in a manner to create a void volume bounded by said bottom wall and said sidewall adjacent the inner sidewall edge of the portion of said sidewall lap joint incorporated in said bottom wall lap joint, (c) prior to step (b), applying caulking material to at least one of said sidewall blank and said bottom wall blank at a location and in an amount which causes said caulking material to block and seal said void volume formed during step (b) to prevent said void volume from becoming a leak path for liquids placed in said container, and (d) sealing said sidewall lap joint and said bottom wall lap joint.