Graham Packaging issued US patent for 'Pasteurizable and hot-fillable plastic container' that features sidewall, base portion that both remain relatively stable under various conditions of pressurization, temperature that occur during such processes

March 13, 2014 () – Graham Packaging Company, L.P. (York, PA) has been issued patent number 8662332, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Wurster, Michael P. (York, PA); Howell, Justin A. (New Cumberland, PA); Kelly, Michael T. (Manchester, PA); Waltemyer, Robert (Felton, PA); Lewis, Benton A. (Manchester, PA).

This patent was filed on October 6, 2009 and was published online on March 4, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "This invention relates to blow molded plastic containers, and particularly blow molded plastic containers that are designed to accommodate the pressurization and vacuum forces that are inherent in the pasteurization and/or hot fill processes.

"Many products that were previously packaged using glass containers are now being supplied in plastic containers, such as containers that are fabricated from polyesters such as polyethylene terephthalate (PET).

"PET containers are typically manufactured using the stretch blow molding process. This involves the use of a preform that is injection molded into a shape that facilitates distribution of the plastic material within the preform into the desired final shape of the container. The preform is first heated and then is longitudinally stretched and subsequently inflated within a mold cavity so that it assumes the desired final shape of the container. As the preform is inflated, it takes on the shape of the mold cavity. The polymer solidifies upon contacting the cooler surface of the mold, and the finished hollow container is subsequently ejected from the mold.

"The use of blow molded plastic containers for the purpose of packaging liquids that are processed by hot filling and/or pasteurization processes has been known for some time. The hot fill process involves filling the containers while the liquid product is at an elevated temperature, typically 68.degree. C. to 96.degree. C. (155.degree. F.-205.degree. F.) and usually about 85.degree. C. (185.degree. F.) in order to sterilize the container at the time of filling. Containers that are designed to withstand the hot fill process are known as 'hot fill' or 'heat set' containers. Such containers are typically designed with sidewalls that include one or more vacuum panels that are designed to flex due to the temperature changes and consequent volumetric expansion and contraction that takes place during processing.

"Pasteurization subjects a container to greater internal pressures and volumetric changes than occurs with hot-fill processing. This is due to the higher processing temperatures, and, therefore, the greater volumetric expansion and contraction of the contained products and associated vapor.

"Hot fill and pasteurizable containers must be designed to be strong enough in the areas outside of the vacuum panel regions so that the deformation that occurs as a result of the volumetric shrinkage of a product within the container is substantially limited to the portions of the container that are designed specifically to accommodate such shrinkage. Ideally, this is done while keeping the container as lightweight as possible, because PET resin is relatively expensive.

"The sidewall portions of hot fill and pasteurizable containers must be designed to prevent excessive deformation, particularly in containers that are not designed to be substantially circular or round as viewed in horizontal cross-section. In addition, the base of such containers must be designed to be stable and to prevent excessive deformation. PET hot fill and pasteurizable containers typically have a modified champagne style base that defines an outer standing ring on which the container is designed to be supported when placed on a flat horizontal surface, and a central, elevated push-up region. The push-up region of such containers has a tendency to deform when the container is under pressure, which can cause the material near the standing ring to roll or deflect outwardly, thus compromising the stability of the base.

"A need exists for an improved blow molded plastic container for use in hot fill and pasteurizable applications that has a sidewall and base portion that both remain relatively stable under various conditions of pressurization and temperature that occur during such processes."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "Accordingly, it is an object of the invention to provide an improved blow molded plastic container for use in hot fill and pasteurizable applications that has a sidewall and base portion that both remain relatively stable under various conditions of pressurization and temperature that occur during such processes.

"In order to achieve the above and other objects of the invention, a blow molded plastic container according to a first aspect of the invention includes a main body portion that is shaped so as to be substantially round in horizontal cross-section. It further includes a champagne-type base portion that has a generally circular standing ring and an elevated push-up portion that is positioned radially inward of the standing ring. The push-up portion has a bottom wall portion that is shaped to define a central region and an annular, substantially straight and substantially vertical rise portion that is positioned immediately radially inward of the standing ring, and that includes a plurality of radially oriented waves, each of said waves extending radially outwardly from said central region to said vertical rise portion.

"According to a second aspect of the invention, a blow molded plastic container includes a main body portion that is shaped so as to be substantially round in horizontal cross-section and a champagne-type base portion. The base portion defines a generally circular standing ring and an elevated push-up portion that is positioned radially inward of the standing ring. The push-up portion has a bottom wall portion that is shaped to define a central region; and a plurality of radially oriented waves. Each of the waves extends radially outwardly from the central region toward the standing ring and is shaped so as to subtend a substantially constant angle along its length.

"These and various other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention."

For the URL and additional information on this patent, see: Wurster, Michael P.; Howell, Justin A.; Kelly, Michael T.; Waltemyer, Robert; Lewis, Benton A.. Pasteurizable and Hot-Fillable Plastic Container. U.S. Patent Number 8662332, filed October 6, 2009, and published online on March 4, 2014.

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