Patent Application
20120099807
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 has 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 might 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, during use of the product, 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, trash bag manufacturers have come up with several methods 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 thermoplastic bag comprises a first panel and a second panel. The first panel and second panel are joined along a first side edge, a second side edge, and a bottom edge. A top edge of the first panel and second panel defines an upper opening of the bag. The first panel is substantially comprised of a first polymer blend with an elastic portion of the first panel comprised of a second polymer blend. The elastic portion of the first panel extends across a width of the first panel. The second polymer blend has a lower modulus of elasticity than the first polymer blend.
It is contemplated that the present invention may be utilized in ways that are not fully described or set forth herein. The present invention is intended to encompass these additional uses to the extent such uses are not contradicted by the appended claims. Therefore, the present invention should be given the broadest reasonable interpretation in view of the present disclosure, the accompanying figures, and the appended claims.
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 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
A modified polymer blend is used for an elastic portion 150 of the drawstring trash bag 100. The elastic 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 of the drawstring trash bag 100 below the hems 142. The modified polymer blend has a lower modulus of elasticity than the remainder of the panels 102 and 104 facilitating the elastic portion 150 of the drawstring trash bag 100 to be stretched over the outside of a trash receptacle. Additionally, the modified 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 while keeping the structural integrity of the bag intact. It is contemplated that several different polymers may be used in the elastic portion 150 including, but not limited to, ethylene-vinyl acetate (EVA), ethylene-acrylic acid (EAA), very low density polyethylene (VLDPE), and ultra low density polyethylene (ULDPE). In some embodiments of the present invention, the modified blend may comprise at least 20% ULDPE or VLDPE. However, in certain preferred embodiments, the modified polymer blend has at least 50% ULDPE or VLDPE.
Referring now to
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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.
