Patent Application
20120121213
Not applicable.
1. Field of the Invention
The present invention relates to improvements in the construction and manufacture of polymeric bags. In particular, the present invention relates to improvements to trash bags.
2. Description of the Related Art
Polymeric bags are ubiquitous in modern society and are available in countless combinations of varying capacities, thicknesses, dimensions and colors. The bags are available for numerous applications including typical consumer applications such as long-term storage, food storage, and trash collection. Like many other consumer products, increased demand and new technology have driven innovations in polymeric bags improving the utility and performance of such bags. The present invention is an innovation of particular relevance to polymeric bags used for trash collection.
Polymeric bags are manufactured from polymeric film produced using one of several manufacturing techniques that are well-known in the art. However, the two most common manufacturing methods for creating polymeric film are blown-film extrusion and cast-film extrusion. Both blown-film extrusion and cast-film extrusion offer certain advantages versus the other. The ultimate selection of a method of manufacture is often driven by considerations such as the desired properties for the final product as well as by financial considerations.
In both blown-film extrusion and cast-film extrusion, an extruder is used to push molten polymeric material through a die. In the case of blown-film extrusion, the film during processing is tubular in shape. In cast-film extrusion, the film during processing is substantially flat. Certain dies also allow for the manufacture of polymeric films having multiple layers co-extruded through a single die. An early die designed to produce multi-layer blown-film tubes is described in U.S. Pat. No. 4,185,954 entitled Die for Extruding Tubes Composed of Plurality of Layers. Furthermore, other types of co-extrusion dies are available which allow for different polymer blends to be extruded through a single die to provide distinct sections across the width, or circumference, of the extruded film. Such dies, for example, may be used with polymer blends having different color additives to provide stripes in the extruded blown-film.
As previously stated, the present invention relates to polymeric trash bags, which are available in several popular configurations such as drawstring trash bags and wave-cut trash bags, the latter of which have two or more flaps extending from the top of the bag. Both drawstring and wave-cut trash bags are popular among consumers and, given their popularity, recent innovations have attempted to improve the bags' performance.
One common complaint, which is applicable to many different types of trash bags, revolves around the tendency of the trash bag to fall into the trash can during use. Specifically, the top of the trash bag, which is placed over the top of the can, often has a tendency to fall into the trash can as the weight of the trash pulls the bag downward into the can.
To address this issue, certain trash bags now provide features intended to enhance the ability of the bag to “grip” the outside of the trash can near the top of the trash can. With respect to drawstring trash bags, elastic drawstrings have been introduced which stretch outward and retract in order to grip the outside of a trash receptacle. However, the physical properties and strength of the panels comprising the trash bags, specifically the area near the top of the bag at or around the hem area, can make it difficult to stretch the mouth of the bag over the perimeter of the trash receptacle.
One prior art attempt to address this problem is to provide perforations or notches near the upper corners of the bag thereby allowing the ends of an elastic drawstring to be separated from the bag proper and stretched over and around the upper opening of a trash receptacle. However, the perforations or notches result in large openings at the top of the bag when it is closed. Additionally, when compared with traditional drawstring trash bags, the perforations and/or notches in the bag can increase the risk that tears will propagate away from the cutouts when stress is placed on the bag.
In view of the foregoing, it would be desirable to provide a trash bag that is easier to extend over the upper opening of a trash can, keeps the structural integrity of the bag intact, and overcomes challenges of the prior art. Additionally, it would also be desirable to provide a trash bag that effectively grips trash cans. The present invention addresses these and other needs.
In one embodiment of the present invention, a trash bag is comprised of a first panel and a second panel joined along a first side edge, a second side edge, and a bottom edge. The top edge of the first panel and second panel defines an upper opening of the bag. The first panel has a normal thickness and further comprises a reduced gauge portion. The reduced gauge portion of the first panel has a thickness that is less than the normal thickness of the first panel. In some embodiments of the present invention, the reduced gauge portion of the first panel extends substantially across a width of the first panel. Additionally, the reduced gauge portion of the first panel may have a substantially uniform height.
In certain embodiments of the present invention, the thickness of the reduced gauge portion may be less than or approximately equal to 80% of the normal thickness of the first panel. Furthermore, in some embodiments of the present invention, the thickness of the reduced gauge portion may be less than or approximately equal to 50% of the normal thickness of the first panel. Additionally, the second panel may also have a normal thickness with a reduced gauge portion of the second panel having a thickness that is less than the normal thickness of the second panel.
In some embodiments of the present invention, a first hem is provided in the first panel with a first drawstring contained within the first hem. Additionally, a second hem may be provided in the second panel with a second drawstring contained within the second hem. In some embodiments, the first drawstring may be elastic or both the first and second drawstring may be elastic. Furthermore, in such embodiments, a reduced gauge portion of the first panel may be provided that includes substantially all of the first hem and may further include an area of the first panel below the first hem. Similarly, a reduced gauge portion of the second panel may be provided that includes substantially all of the second hem and may further include an area of the second panel below the second hem.
A full and complete understanding of the present invention may be obtained by reference to the detailed description of the present invention and certain embodiments when viewed with reference to the accompanying drawings. The drawings can be briefly described as follows.
The present disclosure illustrates several embodiments of the present invention. It is not intended to provide an illustration or encompass all embodiments contemplated by the present invention. In view of the disclosure of the present invention contained herein, a person having ordinary skill in the art will recognize that innumerable modifications and insubstantial changes may be incorporated or otherwise included within the present invention without diverging from the spirit of the invention. Therefore, it is understood that the present invention is not limited to those embodiments disclosed herein. The appended claims are intended to more fully and accurately encompass the invention to the fullest extent possible, but it is fully appreciated that certain limitations on the use of particular terms are not intended to conclusively limit the scope of protection.
Referring initially to
The unsealed top edge 112 of the respective panels 102 and 104 defines the upper opening of the drawstring trash bag. A pair of drawstrings 140 are disposed within hems 142 located proximate the top edge 112 of the respective first panel 102 and second panel 104. The drawstrings 140 may be traditional high-density polyethylene drawstrings or, in some embodiments, may be elastic drawstrings. The drawstrings are generally loose within the hems 142 and sealed near the upper corners of the drawstring trash bag 100 by short seals 120 and 122. Therefore, when the drawstrings 140 are pulled through the drawstring cutouts 144 of the bag 100, the respective upper corners of the bag 100 are pulled together, facilitating closure of the bag.
In the depicted embodiment of
To facilitate the drawstrings 140 in being stretched over certain trash receptacles while still keeping the structural integrity of the bag intact, a reduced gauge portion 150 generally extends across the width of the drawstring trash bag 100 and may generally encompass the hems 142 and may also encompass a small area below the hems 142 as well. The reduced gauge portion 150 has a thickness, or gauge, that is less than the remainder of the trash bag panels 102 and 104. The thickness of the remainder of the trash bag panels 102 and 104 may be referred to herein as the normal gauge or normal thickness of the respective trash bag panels 102 and 104. However, it is understood that the thickness of thin polymeric films may vary and that certain variations in thickness may be expected. Therefore, the gauge and thickness of a polymeric film is usually expressed in terms of an average thickness across a certain area.
In a typical embodiment of the present invention as shown in
In some embodiments of the present invention, the reduced gauge portion 150 may be comprised of the same polymer blend as the remainder of the trash bag panels 102 and 104. For example, in many embodiments of the present invention the trash bag panels 102 and 104 may be comprised primarily of linear-low density polyethylene (LLDPE), which typically makes up over 80% of the polymer blend used for the trash bag panels 102 and 104. IN certain embodiments, the reduced gauge portion 150 may comprise the same polymer blend, comprising at least 80% of LLDPE. However, in other embodiments of the present invention, the polymer blend of the reduced gauge portion 150 may be a modified polymer blend, different from the polymer blend used for the trash bag panels 102 and 104. The modified polymer blend may have a lower modulus of elasticity than the remainder of the panels 102 and 104 facilitating the reduced gauge portion 150 of the drawstring trash bag 100 to be stretched over the outside of a trash receptacle. Additionally, the modified polymer blend may provide greater elastic recovery improving the grip of the drawstring trash bag 100 on the outside of the trash receptacle after being placed over it. It is contemplated that several different polymers may be used in the modified polymer blend, including but not limited to, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ethylene-vinyl acetate (EVA), ethylene-acrylic acid (EAA), very low density polyethylene (VLDPE), and ultra low density polyethylene (ULDPE). As an example, in some embodiments of the present invention, a modified polymer blend of the reduced gauge portion 150 may comprise at least 20% ULDPE or VLDPE. However, in certain preferred embodiments, the modified polymer blend may have at least 50% ULDPE or VLDPE.
Referring now to
Referring now to
As previously noted, the specific embodiments depicted herein are not intended to limit the scope of the present invention. Indeed, it is contemplated that any number of different embodiments may be utilized without diverging from the spirit of the invention. Therefore, the appended claims are intended to more fully encompass the full scope of the present invention.
