MXPA05010341A - Bag with elastic strip and method of making the same. - Google Patents

Abstract

Provided is a plastic bag (100) including a live elastic strip (120) that, in the elastic strip's normal condition, contracts thereby constricting an opening of the bag to assist in retaining the bag to an object. The elastic strip includes a first region (150) that is continuously attached to a sidewall of the bag between a first side edge (106) and a second side edge (108) of the bag and a second region (152, 154) that remains unattached to the sidewall. The attached region does not contract but instead forces the portion of the sidewall to which it is attached to pucker into a serpentine path. The unattached region does contract causing the portion of the sidewall to which it is adjacent to bunch together. Also provided is a method for manufacturing a plastic bag that involves stretching a live elastic tape and continuously attaching a region of the stretched tape to a web of plastic material.

Description

WO 2004/096535 Al l lili Ilflllil [11II 1 (1 (1 ll! H Illil IIII 11! [II tlllKIIg [??? illl fll! BS, H, FR, GB, GR, HU, IE, IT, LU, MC, NL, PT, RO, For two-letler codes and other abbrevialions, referred to the "Guid-SE, SI, SK, TR), OAPI patent (BF, BT, CF, CG, CI, CM, Notes on Codes andAbbreviations ance "appearing at thebegin- GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG). ning of ch regular Issue ofl e PCT Gazette. Publis cd: - with intemational search repon BAG WITH ELASTIC BAND AND METHOD FOR ITS MANUFACTURE FIELD OF THE INVENTION The present invention relates in general to a plastic sheet material and to a method for its production, and more particularly to a plastic sheet material in the form of a bag that includes a band of resilient elastic material and a method for its manufacture. The invention has particular utility in the continuous high-speed production of elasticized plastic filler bags for garbage cans, for example, wherein the elastic properties allow the liner bag to be fixed in place within the garbage can.

BACKGROUND OF THE INVENTION - Plastic garbage bags are produced and sold on a large scale in a variety of shapes and sizes. The vast majority of these bags are made of polyethylene film. The bags generally include side walls that are often joined by one or more seams, a lower end at the bottom that is closed and an open top end. The garbage bag can serve as a liner for a trash can. Conventionally, an upper edge of the bag, which defines the opening, is laminated on an upper lip of the can of trash to place the bag in the open position and to attach the bag to the trash can. It can be difficult to keep the bag in the open position and in a secured relationship with respect to the top of the trash can when the bag is loaded with garbage. The use of an elastic means to secure the open end of a lining bag to the upper edge of a garbage can is a process that is generally known. It is desirable that such upper pouch provides adequate elastic "clamping" the trash can to prevent the bag from falling into the trash when loaded with trash. A problem encountered in making such garbage bags involves the interaction between the elastic material and the film substrate of the bag. For example, the elastic material must be capable of stretching and contracting to provide the desired "hold" but the film substrate is typically not elastic. A binding method used in the incontinence products industry involves the intermittent joining of "bonding stitch" of elastic material on a substrate so that between each two bonding regions there is a discernable unbound length of activated elastic film material by hot. This basic type of pattern can be repeated to make separate intervals or "stitches" of joined and unattached sections. Once the garment has been processed, the unattached portions of the elastic material shrink to provide a gathered and elastic garment. This joining method can also be applied to produce garbage bags with the part elastic upper, as shown in the patent of E.U.A. No. 5,120,138 for Midgley and PCT international patent application number WO 00/39005 for Manchal. There is a need in the art for an improved method of continuous production of elasticized liner bags that is cost effective.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a low-cost bag and an elastic band that extends adjacent an open upper end of the bag that can be pulled on and around the periphery of an object such as a trash receptacle for coupling and holding the bag. bag and the object. The present invention also provides a method for manufacturing said bag in a high speed manufacturing process using a "resilient" or elasticized tape. In one aspect of the invention there is provided a bag including a first side wall and a second side wall joined at a common closed bottom end and along two sealed side edges. On top of the bag, the upper edges of the two side walls form a border defining an opening through which the inner volume of the bag can be accessed. To retain the bag on an object, a prestretched band of "resilient" elastic tape, extending between the first edge, can be attached to at least one side wall. sealed and the second sealed edge proximate the open upper end in a ssed condition. The term "resilient" means that the material has an elastic quality. When the elastic band is not tensioned, or is released so that the ribbon is allowed to contract, the upper open end is pulled together and thus narrows the opening defined by the edge. Accordingly, in order to pull the upper end around an object, the elastic band must be tched to expand the opening. In another aspect of the invention, in order to manufacture the bag described in the foregoing, a ribbon of "resilient" elastic material is tched beforehand under tension, at an expanded length. The pre-tched tape is passed adjacent to a sheet of thermoplastic material that is provided in a continuous manner, termed as a fabric, and the two are joined together continuously along a continuous seam. To prevent the elastic band from contracting after the union and distortion in the fabric, the fabric is kept under constant tension so that it maintains the tched condition of the belt. The tensioned fabric and the attached tape are passed through an additional manufacturing process to make the finished bag. In order to dibute the finished bags, the fabric can be cut into a plurality of bags by means of perforations and wound on a roll in such a way that tension is maintained on the elastic band. To allow the elastic band to contract when attached to the bag, only a portion of the elastic band continuously joins between the first and second sealed edges of the bag. The unbound portion of the elastic band can be contracted when the tension of the bag is released. As the unattached portion contracts, it displaces the side walls of the bag which causes the bag to bunch or bunch and the narrowing of the open upper end. This conction prevents the bonded portion from tearing itself out of the side wall or otherwise deying the bag during web shrinkage. Therefore, an advantage of the present invention is that it provides a thermoplastic bag with an elastic band that can be manufactured quickly and inexpensively in a high-speed production facility. A related advantage is that the invention uses a resilient elastic tape that is provided in a continuous manner which simplifies the manufacturing process of the bags. Another advantage is that the invention provides a simple way of preparing a plurality of elasticised bags for packaging and dibution. These and other advantages of the present invention as well as the additional features of the invention will become apparent from the description that is provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a plastic bag having an elastic band attached thereto, Figure 2 is a perspective view of a plastic bag of Figure 1 mounted to a trash can with the elastic band used to secure the plastic bag to the trash can. Figure 3 is a perspective view of the plastic bag of Figure 1 with the elastic band tensioned under tension. Figure 4 is an enlarged detailed view of the region indicated by arrows 4-4 in Figure 1. Fig. 5 is a cross-sectional view taken along line 5-5 in Fig. 4. Fig. 6 is a cross-sectional view taken along line 6-6 in Fig. 4. Fig. 7 is a generally schematic view illuting a method for producing a bag using a continuous plastic fabric and a resilient elastic tape. Figure 8 is an enlarged exploded view of an elastic band for use with the present invention. Figure 9 is a perspective view of a plurality of plastic bags produced by the method illuted in Figure 7, rolled into a roll. Figure 10 is a perspective view of another embodiment of the present invention in the form of a plastic bag having two elastic bands mounted thereon.

Figure 11 is a perspective view of another embodiment of the present invention in the form of a plastic bag with a mooring fin having an elastic band mounted thereon. Figure 12 is a perspective view of another embodiment of the present invention in the form of a reinforced plastic bag having an elastic band mounted thereon. Figure 13 is a perspective view of another embodiment of the present invention in the form of a plastic bag of pull tape having an elastic band mounted thereon. Figure 14 is a cross-sectional view taken along line 14-14 in Figure 13.

DETAILED DESCRIPTION OF THE MODALITIES OF THE INVENTION Turning now to the drawings, where similar reference numerals refer to similar elements, there is shown in Figure 1 an illustrative bag 00 having a first side wall 102 and a second side wall 104 joined along a closed bottom end 110 common. The lower end 1 10 can be joined by a thermal seal or can be folded into a U-fold or a J-fold. The first and second side walls 102, 104 are joined along a first sealed edge 106 and a second sealed edge 108 and define an open upper end 112. Each side wall 102, 104 includes a respective upper edge 114, 15 with the upper edges 114, 115 forming a border 116 defining an opening 118 through which the inner volume of the bag 100 can be accessed. The side walls can be made of any suitable material such as a thermoplastic material suitable for the high-speed production of waste and food storage bags that include but are not limited to high density polyethylene, low density polyethylene, linear low density polyethylene and / or combinations thereof. Above the bag 100, attached to the first side wall 102 near the open upper end 12 is a band of elastic material 120 extending between the first sealed edge 106 and the second sealed edge 108. The elastic band is parallel to an X axis 130 running along the width of the bag. The elastic band 120 can be placed approximately from 13 mm to approximately 13 cm (0.5-5 inches) from the upper end 112. The attachment of the elastic band 120 to the first side wall can be accomplished by adhesive, heat sealing, stitching or other methods well known in the art. The elastic band is illustrated in a normal condition where the band is not tensioned along the direction of the X-axis 130. Placing the elastic band in the normal condition causes the first side wall to be piled up, thereby closes the opening 8 and causes the bag 100 to acquire a puckered appearance.

With reference to Figure 2, the bag 100 is attached to a garbage can 140. The band allows easy access to the inner volume of the bag and provides a holding force to facilitate assembly of the bag to an object, such as a trash can, in an open position. The bag 100 is shown with the upper end 112 wrapped around an upper lip 142 of the garbage can where the remainder of the bag 100 is inserted into the cavity 144 within the garbage can 140. To fix the bag 100 to the canister 140, the elastic band 120 may allow the upper end 112 to close around the perimeter of the garbage can 140 and thus provide a holding force. To install the bag 100, the upper end 112 can be expanded from its closed position shown in Figure 1. With reference to Figure 3, to expand the opening 1 4, the elastic band 120 can be placed in tension as length of the X axis 130, which in turn causes the elastic band to stretch and expand. The stretching of the elastic band 120 can allow the first and second side walls 102 and 104 to separate. With reference to figure 4, the elastic band 120 is joined to the first side wall 102. The elastic band 120 may include a joined region 150 that is placed between a pair of unbonded edge regions 152, 154. The joined region 150 and the two unlinked regions 152 and 154 are parallel to each other. As illustrated in FIG. 5, the joined region 150 of the elastic band 120 is securely attached adjacent the first side wall 102 while the unbonded edge regions 152 and 154 overlap in a manner that is unattached. release to the first side wall 102. With reference to Figure 1, it is noted that the joined region 150 and the two unattached regions 152 and 154 extend the full width of the bag 100 between the first edge 106 sealed and the second edge 108 sealed. With reference to Figure 4, the joined region 150 and the unbonded regions 52 and 54 of the elastic band 120 have approximately the same height, measured along a Y axis 132, with respect to each other. The Y axis 132 is perpendicular to the X axis 130. For example, the elastic band 120 may be approximately 19 mm (0.75 in.) High with the 150 region attached which is approximately 6 mm (0.25 in.) High. The heights of the two unlinked regions 152 and 154 are approximately 6 mm (0.25 inch) each. Preferably, the total surface area of the joined region 150 of the elastic band 120, i.e., the surface area of the elastic band that joins the first side wall, is equal to or less than the total surface area of the elastic band. unbonded region of the elastic band 120, that is, the first and second regions 152, 154 not joined in this case, according to the following expression: (As / Au) < 1, where As is the surface area of the bound region 150 and Au is the combined surface area of the unlinked region 152, 154. The relationships expressed in the above can be applied to an elastic band with a height between about 13 mm (0.5 inches) to about 3.8 cm (1.5 inches), for example. In others modalities may vary the relationship between the surface area of the bound region and the surface area of the unbound region. With reference to Figure 4, when the tension causing the elastic band 120 to stretch is released, unbonded regions 152, 154 of the contraction of the elastic band cause the side band 102 to bunch up. The joined region 150, which is fixedly attached to the side wall 102, does not contract substantially. Instead, as illustrated in FIG. 6, to adapt the contracted unbonded regions and the piled-up side wall, the joined region 150 of the elastic band and the side wall 02 are shirred in a serpentine path. In other embodiments, the elastic band may include a bound region and a single unbound region. In other embodiments, the number of joined regions and / or regions that are not linked may vary. With reference to Figure 7, an embodiment of a manufacturing process for manufacturing the bag described in the foregoing is illustrated. The manufacturing process can be carried out by automated machinery 200 which operates continuously at high speeds. The elastic material is initially provided as a tape 220 wound on a roll 222. The tape has a continuous length and a width defined in advance, which is defined by the two side edges 226, 228. The belt 220 is unrolled and aligned in a direction 202 of the machine which is superimposed on a continuous web of fabric. 230 thermoplastic material, such as high density polyethylene, adjacent to an upper edge 232. The fabric 230 can be provided from a roll 234 of fabric material that is continuously unwound and advanced through the machine 200 along the direction 202 of the machine. To provide the first and second side walls, the fabric can be folded in half, along the direction 202 of the machine to produce two layers that pass through the machine. In other embodiments, a second fabric of thermoplastic material can be advanced through the machine adjacent to and superimposed by the first fabric 230. The tape 220 can be stretched from its normal condition before it is attached to the fabric. To stretch the tape 220, nip rolls 214 can be provided which pull the tape at a faster speed compared to the speed at which the tapes of the roll 222 are unwound. Preferably, a stretch of between about 30% is introduced. and approximately 50% to the tape before the tape is attached to the fabric. In another embodiment, the ribbon 220 can be stretched after it has passed through the constricting rolls 214 but before it is joined to the fabric 230. A separate region 224 along the width of the band 220 elastic is continuously attached to the fabric by a joining device 204. The tape attaching device can join the elastic tape 220 by thermal sealing, adhesive bonding, stitching or other known joining method commonly in the art. After the tape 220 has been attached to the fabric 230, tension can be maintained on the tape 230 by holding the fabric stretched along the direction 202 of the machine as it advances through the machine 200. In one embodiment , a second ribbon can be unwound from a second roll, it can be aligned in the machine direction overlapping the fabric, and it can be attached to it. For example, the second tape can be joined on a surface of the fabric opposite the surface to which the first tape is to be joined. In embodiments in which the fabric has been folded or multiple fabrics are provided to generate a first and second side walls, the second tape may be attached to the second side wall. As the fabric 230 and the tape 220 advance in the machine direction 202, a bag seal device 206 forms a plurality of side seals 236 on the fabric 230 perpendicular to the machine direction 202. The adjacent side seals 236 are in a predetermined spaced relation to each other. Preferably, the side seals are of a width of approximately 6 mm (0.25 inches) and extend completely through the fabric between the upper edge 232 and the lower end 237. A piercing operation on the fabric 230 can be performed by a perforating device 208 in the form of a blade to produce perforations through the side seals 236. Each perforation 240 is extends longitudinally along the respective lateral seal 236. The two adjacent perforations 240 define a bag assembly along the fabric 230. The fabric 230 can be torn along each perforation 240 to define a pair of side edges, a side edge on two adjacent bags, and to segment elastic band 220 The tear strength of each perforation 240 can be such as to allow the perforation 240 to be manually torn and prevent the perforation 240 from tearing as it advances through the machine 200. In one embodiment, the processed fabric 230 can be wound continuously in a roll 238 by a winder 210. Prior to the winding operation, the fabric 230 can pass through a V-bender assembly 212 that bends the fabric 230 into a smaller size. In the embodiment in which the fabric 230 is wound on a roll 238, the tension of the fabric 230 is preferably maintained so that the elastic tape 220 remains in the stretched condition. The elastic band when in its normal condition has a given width and thickness. Since the belt is stretched under tension during the manufacturing process, the width and thickness can be reduced as the total length increases. To produce a bag with an elastic band of a predetermined width and thickness, an undrawn belt with a larger width and thickness must initially be provided. In the modalities in which the finished bags are distributed on a roll with the perforations intact, the bags can be be coils wound tightly to prevent the elastic bands from contacting their normal positions. For example, with reference to Figure 9, the processed fabric 230 and the bound elastic tape are wound around an axis 240 so that the successive layers of the fabric and the tape are buried and keep the inner layers in the stretched condition. In some embodiments, to facilitate coiling, a core can be provided in the winding operation in which the bag can be rolled. Once the outermost bag is unwound from the roll 238 and separated along the perforation line, tension is removed from the bag and the elastic band contracts to close the opening. The elastic tape 220 may be able to experience rapid stretching and at the same time retain its elasticity. In modalities in which the bag is distributed with the elastic band in its stretched condition, the tape can be constructed in such a way that it does not show significant pleating over extended periods of time (for example, of the order of one year or more). The resistance to pleating of the elastic band can facilitate the use of the bag in situations that require the elastic to be stretched for important periods of time. In addition, the tape can be constructed to resist being bound to the fabric, for example, by a thermal seal. The resilient elastic tape can be made of any suitable material such as EVA (ethylene-vinyl acetate copolymer), VLDPE (very low density polyethylene), Lycra ™ by DuPont, EPDM (ethylene-propylene monomer rubber and diene), and rubber, for example.

In some embodiments, the elastic tape 220 may be provided as a multi-layered structure, as illustrated in Figure 8. For example, the tape 220 may be made from a core layer 72 placed between two coating layers 170, 174. The coating layers 170, 174 can facilitate the bonding of the tape to the fabric while the core 172 can provide the desired elastic properties. With reference to Figure 10, another embodiment of a bag 300 is shown. The bag 300 includes a first side wall 302 and a second side wall 304 that are joined at a common bottom end 310, a first edge 306 sealed and a second edge 306. 308 sealed. This configuration of the bag 300 thus defines an upper end 302 with an opening 314 through which the inner volume can be accessed. Elastic bands 320, 332 are attached to the interior portions of the first and second side walls 302, 304, respectively, adjacent to the upper end 312. Preferably, the elastic bands 320, 322 extend through the side walls 302, 304 between the first sealed edge 306 and the second sealed edge 308. As illustrated, when the elastic bands are allowed to contract to their normal position, the joined side walls are joined together so that they close the opening to the interior volume and give the bag a shirred appearance. With reference to Figure 11, another embodiment of a bag 500 is illustrated which has fins that are tied to facilitate removal and disposal. Specifically, the bag 500 includes a first and second side walls 502, 504 joined by a common bottom end 510, a first edge 506 sealed and a second edge 508 sealed. This design of the bag in this manner defines an upper end 512 having an opening 514 through which the inner volume of the bag can be accessed. Each of the sidewalls 502, 504 includes a fin portion 518, 519 extending from a respective upper edge 516, 517 of the sidewalls 502, 504. The bag 500 may include a band of elastic material 520 that is adjacent. to the upper part 512 open and extending through the first side wall 502 between a first sealed edge 506 and a second sealed edge 508. A second band 522 of elastic material which extends through the second side wall 504 between the first sealed edge 506 and the second sealed edge 508 may also be included. When the elastic bands 520, 522 are in the normal position, as shown in Figure 11, the bag 500 acquires a shirred appearance. To expand the opening, the elastic bands 520, 522 can be stretched along their longitudinal axes. To close the opening 514, they can be joined by knotting the fin portions 518 and 519. With reference to Figure 12, another embodiment of a bag 600 is shown. The bag 600 of Figure 12 is a bag with reinforcements. The bag 600 includes first and second side walls 602, 604 which are joined by a pair of common side reinforcements 606, 608. The bag 600 also includes a closed lower end 610 and an open upper end 6 2 defining an opening 614. It is attached through the first side wall 602 adjacent to the open upper end 612 with an elastic band 620. When the elastic band is allowed to contract to its normal position, as shown in Figure 12, the first side wall 602 is gathered together which provides the bag 600 with a puckered appearance. To expand the opening 614 through the upper end 612, the elastic band 620 can be stretched along its longitudinal axis. With reference to Figure 13, another embodiment of an elastic upper bag 700 is illustrated. The bag 700 of Figure 13 is a belt bag for pulling. The bag 700 includes first and second side walls 702704 which are joined by a common bottom end 710 and sealed side edges 706, 708. The bag includes an upper end 712 having an opening 714 through which the inner volume of the bag can be accessed. An elastic band 720 is attached through the first side wall 702 adjacent the open end 712. When the elastic band 720 is allowed to contract to its normal position, as illustrated in Figure 13, the first side wall 702 is gathered together, which gives the bag 700 a shirred appearance. To expand the opening 714, through the upper end 712, the elastic band 720 can be stretched along its longitudinal axis. To substantially close the open upper end 712, the first and second drawing tapes 730, 732 can be accessed through a plurality of notches 718 and can be operated to constrict the opening 714.

With reference to Figure 14, to provide a channel in which the first pull tape 730 can pass, the first side wall 702 includes a first hem flap 740. The first hem flap 740 is folded back inside the bag 700 and is attached to the interior of the first side wall 702 in a first hem seal 742 to define a first hem 744. The first pull tape 730 is located within the first hem 744. The second pull tape 732 is located in a second hem 754 generated by the second side wall 704, a second hem tab 750 and a second hem seal 752. To join the elastic band 720 to the first side wall 702, a third hem seal 760 can be formed between the first hem tab 740 and the elastic band 720 on the inside of the first side wall 702. The third hem seal 760 about one third 770 of the elastic band 720 is continuously attached to the first side wall 702 and a first hem tab 740 while two-thirds of each elastic band 772, 774 remain unattached. With reference to Figure 13, when allowed to contract to the normal position, the unattached portions 772 and 774 can provide the bag 700 with a puckered appearance. In this way, the present invention provides a plastic bag having a resilient elastic band that can be manufactured quickly and inexpensively in large volumes. The resilient elastic band can be continuously sealed across the width of the bag. The bag will it can pull on itself and can be fastened around the periphery of an object. The present invention also provides a method for processing such bags in large volumes by continuously sealing under tension the resilient elastic tape through a material web which will subsequently be divided into separate bags. The resilient elastic tape may be pre-stretched prior to its attachment to the fabric, which may subsequently be required in tension during the remaining processing steps. All references, including publications, patent application and patents mentioned herein are incorporated herein by reference to the same extent indicated individually and specifically so that it is incorporated by reference and where it has been fully established in the I presented. The use of the terms a ("a" and "an") and "the" ("the") and reference similar in the context describing the invention (especially in the context of the following claims) should be considered to encompass both the singular as the plural, unless otherwise indicated in the present or that clearly contradicts what is contradicted by the context. The mention of the ranges of values herein is intended to simply serve as a shorthand reference method individually to each separate value that falls within the range, unless otherwise stated herein, and each separate value is incorporated in the specification as if it was mentioned individually in it. All the methods described herein can be performed in any adequate order unless otherwise stated in the present or otherwise clearly contradicted by the context. The use of any and all exemplary or exemplary language (eg "such as") that is provided herein is intended merely to clarify the invention better and has no limitation on the scope of the invention, unless that is claimed in another way. No language of the specification should be considered as indicative of an unclaimed element, essential for the practice of the invention. Preferred embodiments of this invention are described herein, and include the best mode known to the inventors to carry out the invention. Of course, variations of these preferred embodiments should become apparent to those ordinarily skilled in the art upon reading the foregoing description. The inventors expect those skilled in the art to use such variations as appropriate and the inventors designed for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents to the subject matter mentioned in the claims appended thereto as permitted by applicable law. In addition, any combination of the elements described in the foregoing in all possible variations thereof is encompassed by the invention unless otherwise indicated in this document or otherwise contradicted by the context.

Claims (25)

1. 22 NOVELTY OF THE INVENTION CLAIMS 1. - A method for manufacturing a bag, comprising: providing a fabric of thermoplastic material; provide a tape of resilient elastic material; stretching the tape along an axial direction; continuously joining a first region of the tape to the fabric with a second region of the tape remaining unjoined; and keeping the tape attached in the stretched condition by keeping the fabric under tension. 2. - The method according to claim 1, further comprising: winding the fabric under tension in a roll. 3. - The method according to claim 2, further characterized in that the fabric is wound around a core. 4. - The method according to claim 1, further characterized by additionally comprising: forming side seals on the fabric. 5. - The method according to claim 4, further characterized by additionally comprising: piercing the fabric and the tape along the side seals. 2. 3 6. - The method according to claim 1, further characterized by additionally comprising: passing the fabric through a folder. 7. - The method according to claim 1, further characterized in that the unbonded region of the tape includes a first and second edge portion and the joined region of the tape is placed on the first and second edge portions. 8. - The method according to claim 1, further characterized in that the joining step is carried out by a process that is selected from the group consisting of adhesive application, heat sealing, stitching and a combination thereof. 9. - The method according to claim 1, further characterized in that the tape is attached close to an upper edge of the fabric. 10. The method according to claim 1, further characterized in that it additionally comprises: folding the fabric in half to produce two superimposed layers. 11. - The method according to claim 1, further characterized by additionally comprising: providing a second adjacent fabric and superimposed on the first fabric. 12. - The method according to claim 1, further characterized in that it further comprises: providing a second tape of resilient elastic material; stretch the second fabric along 24 of an axial direction; and continuously joining a first region of the second tape to the fabric with a second region of the tape that remains unattached. 13. - A bag, comprising: a first side wall; a second side wall, the second side wall is joined to the first side wall by a closed lower end, a first edge and a second edge, whereby an open top end is defined; a band of resilient elastic material having a predefined width, a region of the band is continuously attached to the first side wall while the remaining region of the band remains unattached, the band extends from the first edge to the second edge . 14. - The bag according to claim 13, further characterized in that the band is joined by a union that is selected from the group consisting of adhesive, thermal seal, stitches and combinations thereof. 15. The bag according to claim 13, further characterized in that the joined region has a first surface area, and the unbonded region has a second surface area, the ratio of the first surface area to the second area. of the surface is not greater than about 1. 16. The bag according to claim 13, further characterized in that the band is near and parallel to the open upper end. 25 17. - The bag according to claim 13, further characterized in that it additionally comprises: a second band of resilient elastic material attached to the second side wall. 18. - The bag according to claim 13, further characterized in that the joined region corresponds to the middle portion of the band while the unbound region corresponds to the first and second edge portions of the band. 19. - The bag according to claim 13, further characterized in that the bag comprises a type selected from the group consisting of a reinforced bag, a bag of pull tape and a bag with ties to tie. 20. - The bag according to claim 13, further characterized in that the bag comprises a reinforced bag, and the first and second sealed edges comprise a first and second reinforcements, respectively. 21. - The bag according to claim 13, further characterized in that the bag comprises a bag with pull tape, wherein each of the first and second side walls include first and second respective hemming fins, the first and second Hem fins are respectively attached to the first and second side walls in the first and second respective hem seals and thus define the first and second hems, the pouch further comprises a pull strip positioned within the first and second hems. 26 22. - The bag according to claim 13, further characterized in that the bag comprises a flap bag that is tied where the first and second side walls include first and second fins that are tied or more, which extend from the upper end . 23. - A roll of bags, comprising: a plurality of bags, each bag includes a first side wall, a second side wall joined to the first side wall so as to define a closed bottom end, a first edge, a second edge and an open upper end; the plurality of pouches are distributed to define a length with the first sealed edge of at least one pouch attached to the second sealed edge of an adjacent pouch; a tape of resilient elastic material stretched longitudinally, the tape has a predefined width; a portion of the width of the tape is continuously attached to the length of the plurality of bags; wherein the length of the plurality of bags wound together about an axis normal to the first and second edges of the attached tape, whereby the roll holds the tape together in the stretched condition. 24. - The roll according to claim 23, further characterized in that the length is wound around a core. 25. The roll according to claim 23, further characterized in that the first and second joined edges of the adjacent bags are perforated.