Collapsible pouches are typically used for packaging a wide variety of products involving food, beverages, personal care products, household care products, or other similar or dissimilar products which may be in the form of a liquid, lotion, gel, paste, or the like. Such a pouch is typically made from a flexible, heat-sealable, polymeric sheet or from a flexible, paperboard or metal foil sheet having a heat-sealable, polymeric lining. The pouch typically has two, opposed, flexible web portions peripherally sealed to one another so as to define an interior region, which is adapted to contain the fluent product, and also to define an opening for establishing communication between the pouch interior region and the exterior of the pouch. The opening is adapted to receive a dispensing fitment assembly, which may incorporate a dispensing valve, and a removable cover, or other similar or dissimilar features, and which typically further includes a fitment body molded from a polymeric material that can be heat-sealed to the web portions of the collapsible pouch. Such constructions are commonly referred to as Bag-On-Valve (“BOV”) packages. Some examples of BOV packages can be seen in U.S. Pat. No. RE 39,520 E, issued Mar. 20, 2007; U.S. Pat. No. 6,439,429, issued Aug. 27, 2002; and U.S. Pat. No. 6,273,307 issued Aug. 14, 2001.
It is known to utilize such BOV packages in dispensing systems that utilize a container that is pressurized with a propellant. In such pressurized systems, the pouch of the BOV package is inserted into a pressure capable container with a portion of the fitment assembly engaging an insertion opening of the container to close the container with the pouch hanging from the fitment assembly inside the container. Examples of such dispensing systems can be seen in U.S. Pat. No. Re. 35,540, issued Jun. 24, 1997 and in U.S. Pat. No. 5,169,037, issued Dec. 8, 1992. The weight of the fluent product contained in the collapsible pouch is known to cause stresses in the web portions of the pouch immediately adjacent the fitment body, particularly when the pressurized dispensing system is subjected to impact loads such as when being dropped from a height onto a hard surface. These stresses have been known to cause failures in BOV packages and there is a continuing need to make such constructions more robust in order to reduce such failures.
FIGS. 1-4 illustrate various embodiments of known Bag-On-Valve package constructions. In each of the constructions, the Bag-On-Valve package 10 includes a collapsible pouch 12 and a fitment assembly 14 as previously described. The fitment assembly 14 includes a valve assembly 16 for dispensing a fluent product, a fitment or valve body 18 for mounting the valve 16 in a dispensing passage 19, a dip tube 20 extending from the passage 19 of fitment body 18 into a lower portion of the interior of the pouch 12, and a mounting cup 22 for mounting the package 10 to a fill opening of a pressure capable container. The dispensing passage 19, valve 16 and dip tube 20 extend along a longitudinal axis 23.
The pouch 12 includes two flexible web portions 24 (one facing away from the page), as previously described, that are joined by a pair of laterally spaced, longitudinally extending edge welds 26 defined by inner and outer weld margins 28 and 30, and by a laterally extending top or end weld 32 located at a top or dispensing end 33 of the pouch 12 and bounded by inner and outer weld margins 34 and 36, with the end weld 32 being formed by welding the flexible web portions 24 to each other and to a tailpiece 40 of the fitment body 18. In this regard, the end weld 32 may be formed in a single step process wherein the tailpiece 40 of the fitment body 18 is sandwiched between the flexible web portions 24 and the end weld 32 is formed in a single welding step, or in a multi-step weld process wherein the tailpiece 40 is either first tack welded to the flexible web portions 24 with one or more subsequent weld steps forming the final end weld 32, or wherein the flexible web portions 24 are welded to each other with an opening left for the tailpiece 40 in a first step, the tailpiece 40 inserted into the opening in a second step, and the final form of the end weld 32 being accomplished in one or more subsequent weld steps. As best seen in FIGS. 1 and 2, the pouches 12 may also include gusset welds 38 to define one or more gussets 42 at the bottom of the pouch 12. The welds can be formed using a variety of methods, including heat induction, heat conduction, ultrasonic welding, friction welding, and the like.
In each of the packages 10 of FIGS. 1-4, the portion of the end weld 32 extending across the tailpiece 40 has a maximum width WT parallel to the longitudinal axis 23. In the package 10 of FIG. 1, the inner and outer weld margins 34 and 36 are straight lines that extend perpendicular to the longitudinal axis 23 and parallel to each other over the entire lateral length of the end weld 32. In the embodiments of FIGS. 2-4, the inner and outer weld margins 34 and 36 initially extend perpendicular to the longitudinal axis 23 and then slope downwardly as they extend laterally away from the longitudinal axis 23, with the width WT being maintained over a portion of the end weld 32 that extends laterally past the tailpiece 40 and the spacing between the inner and outer weld margins 34 and 36 being reduced in the sloped regions of the end weld 32. While each of these prior art BOV packages 10 may perform acceptably for their intended function, there is always room for improvement.