This invention pertains generally to bags for holding matter and more particularly to bags adapted to be substantially leak proof. The invention finds particular applicability in the fields of garbage collection and food storage.
The many styles of flexible bags serve a wide variety of applications in the modern world. For example, one common use of bags is as liners for garbage cans and similar refuse containers. These refuse containers that employ liners can be found at many locations from small household kitchen garbage cans to larger, multi-gallon drums located in public places and restaurants. Bags that are intended to be used as liners for such refuse containers are typically made from low-cost, pliable thermoplastic material. The liquid impervious nature of the thermoplastic material is highly desirable for retaining liquids and juices that are often the by-products of discarded garbage. Still, leaks may develop even in the sturdiest of bags due to puncturing of the thermoplastic sidewall material or failure at the seams. Such leakage, as will be appreciated, allows liquids to drain to the bottom of the garbage can or directly onto the floor or ground when the bag is being removed.
Another common use for flexible bags is in the field of food storage. Again, such bags are typically made of a pliable thermoplastic material where the liquid impervious nature of the thermoplastic material helps retain liquids and juices that may be associated with the stored food items thereby both preserving the food items and avoiding messes arising from leakage. Of course, because of particularly harsh applications or through common wear and tear, storage bags used in the food industry may still develop leaks undermining the foregoing accomplishments.
The invention provides a bag adapted for improved leak resistance. The bag includes a flexible sidewall that provides the interior volume. To absorb and retain liquids from items stored in the bag, the bag includes an absorbent-adhesive mixture comprised of an absorbent agent such as a super absorbent polymer that is capable of absorbing and retaining many times its own weight in fluids and can be located in a suitable position within the bag. In addition to the absorbent agent, the absorbent-adhesive mixture can also include an adhesive that helps the mixture remain attached to the bag even when expanding with absorbed liquids. Attachment is beneficial to capture liquids so they do not bypass the absorbent materials.
For additional liquid absorption, the bag can also include a substrate made out of a material such as a non-woven material. The absorbent-adhesive mixture can be applied between the flexible sidewall of the bag and the substrate to attach the two together. Thus, in an aspect, the invention provides a multilayered construction including a pliable sidewall, an absorbent-adhesive mixture, and a substrate. The materials of the absorbent agent and the substrate can be selected to absorb and retain different liquids and thereby improve the leak resistance of the bag.
In further aspects, the bag can include additional features such as odor-neutralizing compositions to reduce or eliminate odors, including foul odors, that may be emitted by the bag's contents. Another possible feature for inclusion is that the sidewalls of the bag can be configured to stretch in order to accommodate objects without ripping or tearing during insertion, thereby further avoiding potential leakage.
Hence, an advantage of the invention is that it provides a thermoplastic bag that is adapted to absorb liquids and thereby avoid leaking. Another advantage is that, in another aspect, the bag can include odor-neutralizing compositions to combat odors that may be generated by the contents of the bag. These and other advantages and features of the invention will become apparent from the detailed description and the accompanying drawings.
Now referring to the drawings, wherein like reference numbers refer to like elements, there is illustrated in
To absorb and retain liquids and juices that often are contained in or the by-product of inserted garbage, an absorbent-adhesive mixture 130 and a substrate 140 can be placed in the interior volume 106. In the illustrated embodiment, the absorbent-adhesive mixture 130 and the substrate 140 are combined into a layered strip 128 that is located along the closed bottom edge 114 where liquids and juices under the influence of gravity are likely to collect. Specifically, the absorbent-adhesive mixture 130 is provided as a thin layer immediately adjacent the thermoplastic sidewalls 102, 104 with the substrate 140 extending over and covering the absorbent-adhesive mixture. In other embodiments, however, the absorbent-adhesive mixture and the substrate can be applied separately and in different locations in the internal volume. The absorbent-adhesive mixture 130 and the substrate 140 function to absorb and retain the liquids that could otherwise leak through seams, punctures, or tears in the pliable sidewalls 102, 104, or spill out through opening 124.
Referring to
The adhesive 134 can be any suitable adhesive that demonstrates, at least initially, viscous properties that enable intermixing of the super absorbent polymer particles 132. The mixture of super absorbent polymers 132 and adhesive 134 forms a gel or paste that can be easily applied to the inner surfaces of the sidewalls. The adhesive should retain some fluid or elastic properties for an extended period of time to accommodate swelling of the super absorbent polymer that may occur during liquid absorption. Examples of suitable types of adhesive include hot-melt, natural or synthetic waterborne, solventborne, extrudable, and pressure sensitive adhesives, and multi-component glues. Other attachment devices may be used, such as, mechanical or chemical devices including tapes, two-sided tapes, hook and loop fasteners, hydrogen bonding, entrapment, heat sealing, and electrostatic charge.
The particular substrate 140 can be any suitable material. Examples of suitable substrate materials include non-woven materials made from natural or synthetic fibers including wood pulp, cotton, rayon, polyester, olefins such as, for example, polypropylene, polyethylene, nylon, or polyester and the non-woven material can be formed by any suitable operation including air laid, carded, wet formed, extrusion, using bonding methods such as chemical bond, mechanical bond, and thermal bond, and processes such as melt blown, spunbond, hydroentangled, needle punched, batting, through-air, calendar, saturation, dry-laid or wet-laid. In the illustrated embodiment, the non-woven material is provided as a flat, continuous, flexible substrate or strip that can be securely bonded by the absorbent-adhesive material 130 to the inner surface of the sidewalls along the closed bottom edge 116.
Like the super absorbent polymer 132, the non-woven substrate 140 also serves to absorb and retain fluids and juices that may be present in the bag 100. The non-woven substrate 140 can be selected or specially treated to absorb and retain certain liquids that are repulsed or exuded by the super absorbent polymer 132. For example, typically super absorbent polymers are highly hydrophilic but tend not to absorb oils or other complex liquids. The non-woven material can absorb and trap these oils and complex liquids in the interstices between the non-woven fibers and in the polymers. Hence, the combination of the absorbent-adhesive material 130 and non-woven material 140 within the bag 100 can therefore absorb and retain a variety of different liquids thereby reducing potential leakage of the same.
The non-woven substrate 140 also provides other advantageous features and purposes. For example, liquids encountering the non-woven substrate 140 can wick through the material so as to be distributed more evenly across the layer of absorbent-adhesive mixture 130. Additionally, the non-woven substrate 140 will provide support for the absorbent-adhesive mixture. More specifically, covering the layer of absorbent-adhesive mixture 130 with the non-woven substrate helps prevent the inner surfaces of the sidewalls 102, 104 from sticking to themselves or to any inserted contents because of the adhesive properties of the mixture. Furthermore, the added layers of absorbent-adhesive mixture(s) 130 and non-woven substrate(s) 140 provides the sidewalls with additional resistance to punctures, breaks, and abrasion.
In other embodiments, instead of utilizing a non-woven material, the substrate 140 can be made from other materials. For example, the substrate 140 can be made from a cellulous based material that similarly provides the absorbent properties and liquid distribution via wicking properties of a non-woven material. The substrate 140 can also be made from wovens, thermoplastic films including apertured films and coextruded films, modified films including embossed or apertured, laminations, and co-extrusions that offer similar supportive properties for the absorbent-adhesive mixture.
In the embodiments where the bags are intended for use as garbage can liners, it may be desirable to include odor neutralizing features to reduce malodorous smells generated from the contained garbage. Examples of odor neutralizing features are disclosed in U.S. patent application Ser. No. 10/717,099 (Publication No. US 2004/0134923), herein incorporated by reference in its entirety. The odor neutralizing features may positively function to absorb and thereby remove the molecules that cause the malodorous smells. Additionally or alternatively, the odor neutralizing features may themselves generate a pleasant fragrance or scent that masks odorous and malodorous smells generated by the garbage, in effect acting like a perfume. Additionally or alternatively, odor absorbers, controllers, inhibitors and synergistic combinations may be used. The materials that provide the odor neutralizing features may be applied to or included in the absorbent-adhesive mixture, the substrate or the thermoplastic sidewalls by any suitable method. Odor absorbers may include molecules possessing a certain structural configuration that enables them to absorb and thus eliminate a broad array of odoriferous molecules. Such materials include, for example, cyclodextrins, zeolites, activated carbon, kieselguhr, chelating agents, chitin, alkali metal carbonates and bicarbonates, metazene, chlorine dioxide, pH buffered materials such as carboxylic acids and the like. Some hydrogel-forming odor absorbing gelling materials, such a polyacrylate gelling material and acrylate grafted starch gelling material, are also useful and these materials also function as fluid absorbing materials. Odor inhibitors may include those components which interrupt the biological processes responsible for malodors, particularly the processes involving the decomposition of food wastes by bacterial and microbial activity. Odor inhibitors may include antimicrobial agents, chelants, and metallic salts. A synergistic combination may include a garbage bag with an odor-neutralizing composition including an odor-absorbing ingredient selected from the following group: cyclodextrin, activated charcoal, baking soda, absorbent gelling materials, zeolites, silica, and combinations thereof; a chelant; and, an antimicrobial agent.
In further embodiments, the thermoplastic sidewalls of the bag can be configured to stretch or yield to accommodate cumbersome or bulky objects without puncturing, thereby further preventing leaks. Referring to
Referring to
Referring to
While for garbage can liners, it will generally be preferable to locate the absorbent-adhesive mixture and the substrate along the closed bottom edge of a bag where liquids will typical flow, when the bag is intended for other applications, the materials can be provided at any location within the bag where they are likely to encounter liquids. For example, referring to
In the illustrated embodiment, the absorbent-adhesive mixture and substrate are provided as combined strips. As described before, a first strip 450 of combined materials is adhered to the first sidewall along the closed bottom edge 414 and extends between the first and second side edges 410, 412. However, a second strip 452 of the combined materials is provided proximately about the opening 424 of the bag 400. Additionally, a third strip of material 454 can be provided extending diagonally across the first sidewall 402 from the junction of the first side edge 410 and the opening 424 to the junction of the second side edge 412 and the closed bottom edge 414. In different embodiments of the bag, various combinations of strips and their locations can be included. For example, the bag may include only one strip of material extending across the opening or may include only one strip of material extending diagonally across the first sidewall.
Another embodiment of a bag including an absorbent-adhesive mixture and a substrate is illustrated in
Another embodiment of a bag including an absorbent-adhesive mixture and a substrate is illustrated in
Another embodiment of a bag including an absorbent-adhesive mixture and a substrate is illustrated in
The inventive bags may be provided with any of various closure mechanisms for closing the opening. For example, referring back to the embodiment illustrated in
Referring back to the embodiment illustrated in
Manufacturing of a bag having an absorbent-adhesive mixture and a substrate can be accomplished in a high speed, semi-automated environment such as that illustrated in
In a subsequent step 810, the draw-tape 812 can be received into hemseals that are simultaneously formed into the web material 802. The draw-tape 812 itself can be provided as a continuous strip of material that is unwound at step 814 and aligned in the machine direction 804 prior to the hemseal formation step 810. After the inserting the draw-tape 812, to provide the web material 802 with a plurality of first regions and a plurality of second regions raised with respect to the first regions and thereby provide the web with an elastic quality, in step 816, the web material can be embossed or otherwise manipulated.
Next, the absorbent-adhesive mixture 820 and substrate material 822 can be attached to the advancing web in an attachment operation 824. If the web 802 has already been folded in half and joined together or a second web has been added and joined to the first web to provide the opposing first and second sidewalls of the finished bag, the attachment operation 824 can be preceded by a opening operation 818 wherein the sidewalls are separated to allow attachment of the materials. The substrate material 822 can be provided as a continuous strip of material that is unwound in an unwinding operation 826. The absorbent-adhesive mixture 820 is first prepared by mixing in a mixing operation 828 the required amounts of the absorbent agent 830 and the adhesive 832. The absorbent-adhesive mixture 820 can then be applied along one or both of the surfaces of the substrate material 822 and the combination attached to the web 802 via the attachment operation 824. Multiple layers of absorbent-adhesive mixtures and substrates may be used.
In other possible manufacturing environments, the mixing operation 828 that premixes the absorbent agent 830 and the adhesive 832 can be eliminated. In such instances, the absorbent agent 830 can be directly applied to web material 802 then coated with the adhesive 832 to secure the absorbent agent in place. The substrate material 822 is then placed over and bonds to the adhesive 832. It is possible in other embodiments to reverse the process by applying first the adhesive 832 to the web material 802 and then applying the absorbent agent 830 over the adhesive. The substrate material 822 can then be placed over and pressed against the absorbent agent 830 forcing adhesive 832 through the adsorbent agent so as to contact and bind to the substrate. The absorbing agent and the adhesive can also be obtained in a pre-mixed form.
After the absorbent-adhesive mixture 820 and substrate material 822 have been attached to the web 802, production of the bag resumes in step 840. The bag manufacturing step 840 can involve various folding, sealing, cutting and perforating operations to manipulate the web 802 into finished bags. The finished bags can remain joined together along perforated side edges such that they can be rolled onto a core in a winding operation 842 for packaging and distribution.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US06/20759 | 5/31/2006 | WO | 00 | 2/26/2008 |
Number | Date | Country | |
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60689249 | Jun 2005 | US |