Glad Trash Bag Patents and an Absorbent Strip Innovation

Introduction

The designation "U.S. Patent" or "Patent Pending" is found on many household products. This designation provides notice to the public and potential inventors that the product has been patented, or is in the process of being reviewed to receive a patent, and has protection afforded by the laws enforced by the United States Patent and Trademark Office (USPTO). This paper overviews three currently issued patents: Patent #5,205,650 for the Glad Force Flex trash bag, Patent #5,006,380 for the Glad Tall Kitchen trash bag, and Patent #5,246,110 for the Glad Quick-Tie trash bag. A comparison and contrast of these three patents is explored.

This discussion is followed by a description of a proposed patent improvement: an absorbent strip in the bottom of each bag, similar to the material found in baby diapers. This absorbent strip would absorb any liquids that gather in the bottom of the bag, preventing them from leaking out. Details of this improvement are provided, along with the reasons it is important. How the improvement meets USPTO patentability requirements is also discussed, and a sketch of the proposed design is presented.

Patent Overview

Patent #5,205,650 focuses on stretchable strength in trash bags and is used today in the Glad Force Flex brand. The patent applicants begin by noting that forming bags from orientable thermoplastic polymeric film material is performed through a variety of methods to ensure the film has adequate strength for its intended purpose. However, despite these precautions, there is a chance that during use the bag will rupture when sudden forces are applied. The applicant uses the example of a bag filled with powder or granules rupturing when dropped. Although this tendency to rupture is more common in more rigid polymers, even less rigid polymers, such as low-density polyethylene, have a tendency to rupture upon sudden impact. For this reason, the applicant surmises that it would be desirable to increase the energy absorption properties of the film material used to manufacture trash bags and reduce its tendency to rupture ("United States Patent 5205650," 1993).

Patent #5,205,650 is concerned with methods of spreading tension and other forces in the film material to minimize the risk of rupture. Because the patent concerns the design of the film material itself, it is not specific to trash bags, though Glad uses this invention to manufacture its Force Flex brand. The patent applicant notes that there are a variety of uses for the film material. It can be used to manufacture a major portion of an article — for example, as strapping for parachutes to minimize the risk of rupture under impact — or it can be used for smaller portions of an article, such as the zones in bags most liable to rupture. The applicant further states that the rupture zone can be determined by theoretical considerations or, more practically, through experiments involving dropping full bags ("United States Patent 5205650," 1993).

The seam in a bag is often associated with a rupture zone. The film material adjacent to a seam is more likely to experience a rupture than elsewhere in the bag. The applicant theorizes that the forming of the seam adversely affects the film material's properties in that area. In gusseted bags, the rupture zone is most often found at the junction between side gussets and the seam. A bag may, of course, have more than one rupture zone ("United States Patent 5205650," 1993).

To address this problem, the applicant designed an orientable thermoplastic polymeric film material that can be formed into a bag with a shock-absorbing zone. This material is comprised of at least one stretched zone that extends in a direction leading substantially away from the rupture zone — in which the film material has been stretched substantially in that direction — and a plurality of substantially unstretched zones adjacent to and extending in substantially the same direction as each zone, whereby the rupture forces are transmitted away from the rupture zone by the unstretched zones and into the stretched zone or zones ("United States Patent 5205650," 1993).

For the Glad Force Flex bags, the bags are made entirely of this material design. The patent applicant would likely have applied the material only to the rupture zones adjacent to the seams; however, Glad has applied it to the bag as a whole in order to minimize ruptures anywhere in the bag.

Patent #5,006,380 concerns what the applicant describes as draw-tape bags. Glad has adopted this invention in their drawstring bags, such as the Glad Tall Kitchen trash bags. The draw tape is formed from a multilayer structure of at least two different thermoplastic materials. There are multiple reasons the inventor chose a multilayer design for the draw tape ("United States Patent 5006380," 1991).

The patent applicant surmises that using two or more materials to produce the draw tape is advantageous over a single-layer tape formed from a blend of the same materials. Multiple layers allow the use of a strong tape that gives the draw tape strength without negatively affecting the seal strength of the heat seals to the bag panels. It is also noted that strong thermoplastic materials do not have satisfactory tactile qualities due to their harder surface, which can cut the user's hand when the draw tape is used as a handle. As the draw tape is made from harder material, it becomes more uncomfortable when weight is added to the bag and force is applied. In addition, stronger materials such as high-density polyethylene do not form heat seals as readily as weaker thermoplastic materials ("United States Patent 5006380," 1991).

In the past, the problems associated with using stronger thermoplastic materials for the draw tape — tactile challenges and reduced heat-seal strength — were overcome by physically blending two thermoplastic materials into a single layer. The example of a draw tape made from 50 weight percent low-density polyethylene and 50 weight percent high-density polyethylene is given. This process does impart some properties from each material; however, it does not deliver the best properties of either — namely, the full strength of high-density polyethylene or the heat sealability of low-density polyethylene ("United States Patent 5006380," 1991).

Patent #5,006,380 overcomes the limitations of the single-layer, multi-material blended draw tape. Instead of a single layer, the draw tape is formed from at least two layers of two different thermoplastic materials. The first layer is made from a material that has the ability to form a strong heat seal with the thermoplastic film used for the bag — possibly even the same material as the bag panels. The second layer is made from a stronger material that does not have the same heat-sealing capability ("United States Patent 5006380," 1991). This invention allows the draw tape to have the tactile and heat-sealing advantages of low-density polyethylene, making it comfortable for consumers to use as a handle, while also providing the strength afforded by high-density polyethylene.

Patent #5,246,110 focuses specifically on plastic trash bags. The patent applicant notes that bags typically used for storing and transporting garbage or refuse are made from plastic material. In their flat condition, they consist of two rectangular panels connected on three of the four sides, with the fourth, open side used to insert matter into the bag. These types of bags are typically manufactured via a tubular extrusion process ("United States Patent 5246110," 1991).

These bags are widely used, particularly for collecting kitchen refuse. One challenge of traditional drawstring bags is that they are often difficult to close, especially when substantially full, which frequently leads to spillage. In addition, animals such as dogs may destroy the bags to access the contents. In an effort to prevent these problems, consumers sometimes tie the corners of the bag's open top together, which significantly reduces the bag's holding capacity ("United States Patent 5246110," 1991).

Past attempts to rectify this problem involved modifying the shape of the bag so that projections or tie parts would help close the open end. Although these earlier designs did improve closing performance, they also reduced the bag's capacity. Two previous patents featured tie parts projecting from the bag so that the tails could be tied together; however, these two-tie-part designs are inferior to the four-tie-part design of this patent ("United States Patent 5246110," 1991).

Another previous patent did use four tie parts; however, in that earlier design the bags were gusseted, which reduced the ratio of bag capacity to the amount of plastic used. Instead, Patent #5,246,110 features four tie parts formed "from rounded peaks, separated by concave valleys with each peak having side portions which has a convex part including convex transitional portions respectively connected to the side portions at one end thereof" ("United States Patent 5246110," 1991). This design utilizes the flat-bag system found traditionally with other trash bags, minimizing the amount of material used in manufacture while not negatively affecting storage capacity.

Distinguishing and Differentiating the Three Patents

All three patents have been applied to Glad trash bag lines. In the case of the Glad Force Flex brand, two of the three patents are applied simultaneously — Patent #5,205,650 and Patent #5,006,380. Despite being applied to the same product type, all three are entirely unique in their focus.

Patent #5,205,650 deals specifically with the rupture resistance of the bag material itself. As applied to the Force Flex brand, these trash bags offer superior stretchable strength. Although the invention could have simply been applied to zones most prone to rupturing, Glad has applied it to the entire bag, minimizing the risk of ruptures anywhere. In contrast, Patent #5,006,380 has nothing to do with the bag material at all.

Patent #5,006,380 focuses solely on the drawstring, achieving both the heat sealability and tactile qualities of low-density polyethylene while still utilizing the strength of high-density polyethylene. The bag material itself could be of the Force Flex design or a traditional thermoplastic film design. This closure option is, of course, in competition with Patent #5,246,110.

Patent #5,246,110 is a different type of closure system. Unlike the draw-tape system utilized by Patent #5,006,380, this patent does not use an additional component to facilitate closing. Instead, the design of the bag itself incorporates the closure method through four tie parts. This patent can be used with the Force Flex material design of Patent #5,205,650 or with any other traditional bag design; however, it is used in place of the draw-tape method described in Patent #5,006,380.

Conclusion

Patent #5,205,650, #5,006,380, and #5,246,110 all feature upgrades to the standard thermoplastic film trash bag. While one patent focuses on improving the impact strength of the bag material, the other two focus on closure devices. All three designs help minimize the number of spills and ruptures that occur during normal use.

One of the largest remaining challenges with trash bags is the tendency for liquids to pool in the bottom of the bag. To compound the problem, although some advancements have improved rupture resistance, none has prevented a bag from experiencing a breach via a tiny pinprick. To address these challenges, it is recommended that an absorbent strip be affixed along the entire interior bottom of the bag. This strip would capture any liquids present and prevent them from escaping regardless of where a breach might occur. This proposed patent is both original and non-obvious, and represents a meaningful advancement in trash bag design.

References

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