HK1158594A - Bag with reinforcing features - Google Patents

Description

Bag with reinforcing member

Cross Reference to Related Applications

This application claims priority to U.S. provisional application No.61/091,143, filed on 22/8/2008, which is incorporated herein by reference in its entirety.

Disclosure of Invention

In many applications of thermoplastic bags, it is common to use thermoplastic bags as liners in trash containers or bins. Trash containers employing such liners are used in many applications from small household kitchen trash cans to large multi-gallon drums in public places and restaurants. Bags used as liners for such trash receptacles are typically made of inexpensive soft thermoplastic materials. When the container is full, the thermoplastic liner containing the waste can be removed for further disposal and replaced with a new liner.

It is desirable to minimize the cost of manufacturing disposable thermoplastic bags. Accordingly, such bags are typically mass produced in a high speed manufacturing environment. Other cost savings may be realized by reducing the amount or quality of thermoplastic material used to make the bag. However, those skilled in the art will recognize that reducing the amount or mass of thermoplastic material forming the bag limits the strength of the bag and makes the bag susceptible to tearing or rupturing. Accordingly, there is a need for thermoplastic bags designed in a manner that reduces material costs while maintaining strength and facilitating high speed manufacturing.

The thermoplastic bag may be used as a trash container liner that includes a reinforcing member to prevent rupture or puncture. In an embodiment, the bag may include opposing first and second sidewalls made of thermoplastic material that overlap and connect to each other along a bottom edge to provide an interior volume for receiving waste. The sidewalls are left unconnected along a top edge opposite the bottom edge to provide an opening for accessing the interior volume. The reinforcing member may be a strip of reinforcing material adjacent to and attached to the bottom edge. The reinforcing strip provides an additional layer to reinforce the bag in areas prone to breakage or damage. The reinforcing strip may be made of a thinner material, the same thickness material, or a thicker material than the first and second sidewalls. The reinforcing strip may be made of a material having a lower strength, the same strength, or a material having a higher strength than the first and second sidewalls. In various embodiments, the reinforcing strip may be inserted inside the bag and attached near the bottom edge, or the reinforcing strip may be folded near the outside near the bottom edge.

The present invention can provide a method for manufacturing a bag having a reinforcing tape at high speed. The manufacturing process uses a continuous web and/or strip of thermoplastic material that has previously been passed through various processing equipment that processes the web and/or strip into a plurality of individual finished bags. Because the bags are made from a continuous web processed through the processing equipment, a high speed manufacturing environment is achieved, ultimately reducing the added cost of each bag.

The present invention can provide a thermoplastic bag comprising opposing first and second sidewalls that overlap and are joined to one another along a closed bottom edge and sealed side edges to provide an interior volume. The sidewalls are left unconnected along a top edge opposite the bottom edge to provide an opening into and out of the interior volume. To provide the stiffening member, the thickness of the first and second sidewalls is thicker near the closed bottom edge than near the open top edge. In various embodiments, the first and second sidewalls may be made from the same web of thermoplastic material, or may be made from two separate webs of thermoplastic material that are joined together.

Drawings

FIG. 1 is a perspective view of a thermoplastic bag including reinforcing strips inserted into the bag near the bottom edge of the bag.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, showing the reinforcing strip inserted into the bag.

Fig. 3A-3D are cross-sectional views of the area indicated by circle 3-3 in fig. 2 showing an embodiment of a thermoplastic bag having a reinforcing strip.

FIG. 4 is a perspective view of another embodiment of a thermoplastic bag including reinforcing strips folded near the bottom edge of the bag.

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4 showing the reinforcing strip folded near the bottom edge of the bag.

Fig. 6 is a perspective view of the area indicated by circle 6-6 in fig. 1 showing a thermoplastic material suitable for use in a bag and having stretchable or deformable characteristics, the material being in an unstretched condition.

FIG. 7 is a perspective view similar to FIG. 6, showing the thermoplastic material in a semi-stretched condition.

FIG. 8 is a schematic view of a thermoplastic bag processing environment for making bags with reinforcing strips attached to the web prior to folding the web.

FIG. 9 is a schematic view of another embodiment of a bag processing environment in which folded reinforcement strips are inserted into a folded web.

FIG. 10 is a top plan view of the bag processing environment of FIG. 9 showing the insertion of folded reinforcing strips into the folded web.

FIG. 11 is a schematic view of another embodiment of a bag processing environment in which the reinforcing strips are folded over a folded web.

FIG. 12 is a front plan view of the environment of FIG. 11 schematically illustrating a first process step for reinforcing a web with reinforcing strips.

FIG. 13 is a front plan view of the environment of FIG. 11 schematically illustrating a second process step for reinforcing the web with reinforcing strips.

FIG. 14 is a front plan view of the environment of FIG. 11 schematically illustrating a third process step for reinforcing the web with reinforcing strips.

FIG. 15 is a schematic view of another embodiment of a bag processing step in which bags are made from first and second webs each having a reinforcement.

Fig. 16 is a cross-sectional view taken along line 16-16 of fig. 15, showing the components of the bag being processed.

FIG. 17 is a top plan view of another embodiment of a bag processing environment in which the folded web is partially separated and reinforcement strips are inserted into the separated web.

Fig. 18 is a cross-sectional view taken along line 18-18 of fig. 17 showing the structure of the separating web and reinforcing strips in the bag processing environment.

Fig. 19 is a cross-sectional view taken along line 19-19 of fig. 17.

FIG. 20 is a top plan view of another embodiment of a bag processing environment in which a folded web is partially separated by a V-shaped plate and a reinforcing strip is inserted into the separated web.

Fig. 21 is a cross-sectional view taken along line 21-21 of fig. 20 showing the structure of the separating web and reinforcing strips in the bag processing environment.

Fig. 22 is a cross-sectional view taken along line 22-22 in fig. 20.

FIG. 23 is a schematic view of a bag processing environment having multiple manufacturing steps or stages, including the step of attaching reinforcing strips to a web to provide reinforced thermoplastic composite bags.

Fig. 24 is a front elevation view of an embodiment of a thermoplastic bag with reinforcing strips, wherein a portion of the bag has been provided with a web-like structure that is deformable under tension as shown in fig. 6 and 7.

FIG. 25 is a schematic diagram showing a processing environment for making a thermoplastic web and reinforcing strips from the same material.

FIG. 26 is a cross-sectional view similar to FIG. 2 showing a thermoplastic bag having a reinforced bottom edge made from a single extruded web.

FIG. 27 is a cross-sectional view similar to FIG. 2 showing a thermoplastic bag having a reinforced bottom edge made from first and second extruded webs joined together.

Detailed Description

Referring to fig. 1, an embodiment of a flexible bag 100 is shown. Although flexible bags are generally capable of holding a variety of different contents, the particular bag 100 shown in fig. 1 may be used as a liner for a trash can or similar trash receptacle. The bag 100 may be made from a first sidewall 102 and an opposing second sidewall 104 that covers the first sidewall to provide an interior volume 106 therebetween. The first and second sidewalls 102, 104 may be connected along a first side edge 110, a parallel or non-parallel second side edge 112, and a closed bottom edge 114 extending between the first and second side edges. The sidewalls 102, 104 may be joined along the first and second side edges 110, 112 and the bottom edge 114 by any suitable process, such as heat sealing.

To access the interior volume 106, for example to deposit waste or trash, the top edges 120, 122 of the first and second sidewalls 102, 104 remain unattached to each other to define an opening 124 located opposite the closed bottom edge 114. When placed in a trash receptacle, the top edges 120, 122 of the first and second sidewalls 102, 104 can be folded over the edges of the trash receptacle.

The first and second sidewalls 102, 104 may be made of a flexible or conformable thermoplastic material formed or drawn into a smooth, thin-walled web or sheet. Examples of suitable thermoplastic materials may include polyethylene (e.g., high density polyethylene, low density polyethylene, linear low density polyethylene), polypropylene, ethylene vinyl acetate, nylon, polyester, ethylene vinyl alcohol, ethylene methyl acrylate, or other materials, and may be formed from combinations of these materials, and may be formed as a single layer or as multiple layers. When used as a trash can liner, the thermoplastic material may be opaque, but in other applications may be transparent, translucent, or colored. Furthermore, the material for the side walls may be a gas impermeable material.

To reinforce bag 100 to reduce cracking or puncturing, the bag may include a reinforcing member in the form of reinforcing strip 130 attached to bag bottom edge 114 proximate bag bottom edge 114. In the illustrated embodiment, the reinforcement strip 130 may be inserted into the interior volume 106 between the first and second sidewalls 102, 104. The reinforcing strip 130 may extend between the first and second side edges 110, 112 to be coextensive with the bottom edge 114. Referring to fig. 2, the reinforcing strip 130 provides an additional layer of material over the area of the bag 100 that is susceptible to breakage due to gravity pressing the weight of the contents against the bottom edge 114. This area is prone to breakage because, when replacing the liner in a trash receptacle, the user can grab the bag 100 around the opening 124 and drag the bag along the floor or ground, causing the bottom edge 114 to wear.

The reinforcement strip 130 may be made of a variety of suitable thermoplastic materials, including, for example, polyethylene such as high molecular weight high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, ethylene vinyl acetate, nylon, polyester, ethylene vinyl alcohol, ethylene methyl acrylate, or other materials, and may be formed from combinations thereof and formed into a single layer or multiple layers. In various embodiments, the material of the reinforcing strip may have a higher strength and abrasion resistance than the material of the bag sidewalls 102, 104. Making the reinforcing strip from a stronger and/or tougher material helps prevent the bag from breaking and/or puncturing.

The reinforcement strip 130 may be formed as a single, elongated strip of rectangular material that may be attached to the bottom edge. Referring to fig. 2, the rectangular reinforcing strip 130 may be folded in half along its length to form a first half 132 and a second half 134. The folded reinforcement strip 130 may be inserted into the interior volume 106 and the first and second halves 132, 134 may be attached to the respective first and second sidewalls 102, 104. The reinforcing strip may be attached to the side walls by a variety of suitable methods, including heat sealing the materials together or using an adhesive.

Referring to fig. 3A, the sidewall may have a thickness 150. The thickness 150 may have a first range of about 0.0005 inches (0.0013 cm) to about 0.0014 inches (0.0036 cm), a second range of about 0.0006 inches (0.0015 cm) to about 0.001 inches (0.0025 cm), and a third range of about 0.0007 inches (0.0018 cm) to about 0.00085 inches (0.0021 cm). In one embodiment, the thickness 150 may be about 0.0008 inches (0.0020 cm). The band 130 may have a thickness 152. The thickness 152 may have a first range of about 0.0001 inches (0.00025 cm) to about 0.0006 inches (0.0015 cm), a second range of about 0.00025(0.00064 cm) to about 0.0005 inches (0.0013 cm), and a third range of about 0.00035 inches (0.00089 cm) to about 0.00045 inches (0.0011 cm). In one embodiment, the thickness 152 may be 0.0004 inches (0.001 cm).

Referring to fig. 3B-3D, to facilitate attachment of the reinforcing strip 130 to the bag sidewall, in various embodiments, the reinforcing strip and/or the sidewall may be fabricated as a multi-layer structure. Referring to fig. 3B, the belt 130 may include a first layer 156, a second layer 157, and a third layer 158. The first layer 156 and the third layer 158 may comprise polyethylene (e.g., low density polyethylene or very low density polyethylene), ethylene vinyl acetate copolymer and ethylene methyl acrylate, or other materials. The second layer 157 may comprise polyethylene, for example, high density polyethylene, linear low density polyethylene, high molecular weight high density polyethylene, low density polyethylene, or other materials. The sidewalls 102, 104 may include a first layer 160, a second layer 161, and a third layer 162. The first layer 160 and the third layer 162 may comprise polyethylene (e.g., low density polyethylene or very low density polyethylene), ethylene vinyl acetate copolymer, and ethylene methyl acrylate, or other materials. The second layer 161 may comprise polyethylene, such as high density polyethylene, linear low density polyethylene, high molecular weight high density polyethylene, low density polyethylene, or other materials. The first layer 156 of the band 130 may be in direct contact with the first layer 160 of the sidewall. The first layer 156 can better bond with the first layer 160 if the first layer 156 of the tape is the same as or compatible with the first layer 160 of the sidewall.

The thickness 164 of the multi-layer sidewall 130 may be the same as the thickness 150 of the single-layer sidewall 102 described above. The thickness 166 of the multi-layer band 130 may be the same as the thickness 152 of the single-layer insert 130 as described above. The thickness of the first and third layers 160, 162 may be a weight percentage of the thickness 164 of the sidewalls. The total weight percent of the first and third layers 160, 162 can have a first range of about 1% to about 99%, a second range of about 15% to about 75%, and a third range of about 30% to about 50%. In one embodiment, the total weight percent of the first and third layers 160, 162 may be about 40%, such that the first layer 160 is about 20%, the second layer 161 is about 60%, and the third layer 162 is about 20%. In other embodiments, the first and third layers may have different thickness weight percentages, for example, 30% for the first layer and 10% for the third layer. The thickness of the first and third layers 156, 158 may be a weight percentage of the belt thickness 166. The total weight percent of the first and third layers 156, 158 can have a first range of about 1% to about 99%, a second range of about 15% to about 75%, and a third range of about 30% to about 50%. In one embodiment, the total weight percent of layers 156, 158 may be about 40%, such that first layer 156 is about 20%, second layer 157 is about 60%, and third layer 158 is about 20%. In other embodiments, the first and third layers may have different thickness weight percentages, for example, 30% for the first layer and 10% for the third layer. Referring to fig. 3C, a single layer sidewall may be combined with a multi-layer tape. Referring to fig. 3D, the multi-layered sidewall may be combined with a single-layered tape. In other embodiments, the sidewalls and/or the tape may have two, four, five, six, or more layers.

Referring again to fig. 2, the first half 132 of the stabilizing strip 130 may extend only a partial distance along the first sidewall 102, adjacent the first sidewall, from the closed bottom edge 114 toward the opening 124 of the bag 100. The bag 100 may have a height 138 measured between the closed bottom edge 114 and the opening 124. The first half 132 may have a height 139 measured from the closed bottom edge 114 toward the opening 124. The height 138 may have a first range of about 20 inches (50.8 centimeters) to about 48 inches (121.9 centimeters), a second range of about 23 inches (58.4 centimeters) to about 33 inches (83.8 centimeters), and a third range of about 26 inches (66 centimeters) to about 28 inches (71.1 centimeters). In one embodiment, the height 138 may be 27.375 inches (69.5 centimeters). The height 139 may have a first range of about 1 inch (2.54 cm) to about 10 inches (25.4 cm), a second range of about 3 inches (7.6 cm) to about 8 inches (20.3 cm), and a third range of about 4 inches (10.2 cm) to about 6 inches (15.2 cm). In one embodiment, the height 139 may be 5 inches (12.7 centimeters). As shown, the second half 134 may extend a similar distance along the second sidewall 104. It should be appreciated that because the reinforcement strip extends over only a portion of the side walls, the reinforcement strip includes substantially less material than the side walls. Thus, material of the reinforcement strip is saved by using the reinforcement strip in the desired area. In addition, this becomes advantageous by concentrating a minimum amount of such materials in the best application location when the reinforcement strip is made of a higher strength, more expensive material.

Referring now to fig. 4 and 5, another embodiment of a thermoplastic bag 200 including a reinforcing strip 230 is shown. The bag 200 may include a first sidewall 202, the first sidewall 202 overlying and connected to a second sidewall 204 to provide an interior volume 206. The first and second sidewalls 202, 204 may be connected along a first side edge 210, a spaced apart second side edge 212, and a closed bottom edge 214 extending between the first and second side edges. To access the interior volume 206, the top edges 220, 222 of the respective first and second sidewalls remain unconnected to provide an opening 224.

To reinforce the bottom edge 214 from cracking and puncturing, a reinforcing strip 230 may be attached to the bag 200. In the illustrated embodiment, the reinforcing strip 230 may be attached to the exterior of the bag 200 and may extend from the first side edge 210 to the second side edge 212 along the bottom edge 214. The reinforcing strip 230 may be manufactured as an elongated rectangular strip that may be folded in half along its length near the bottom edge 214 such that the first half 232 may extend adjacent the outer surface of the first sidewall 202 and the second half 234 may extend adjacent the outer surface of the second sidewall 204. Thus, in this embodiment, the reinforcing strip may be located outside the bag, as opposed to the embodiment of figures 1 and 2 where the reinforcing strip is located inside the bag. The reinforcing strip 230 provides an additional layer of material along the bottom edge 214. Additionally, the first half 232 and the second half 234 may extend only half way toward the top opening 224, such that the additional material is primarily placed in areas that are prone to breakage. The reinforcing strip may have a range of dimensions as described above. In various embodiments, the reinforcement strip 230 may be made of a material having higher strength and wear characteristics than the material of the sidewalls 202, 204 described herein. In addition, the reinforcing strip may be fabricated as a single layer or as multiple layers as described herein.

In addition to the reinforcing strip, the bag may include other features that aid in its use as a liner for a trash receptacle. For example, referring again to fig. 1 and 2, to close the opening 124 of the bag 100 when, for example, the trash receptacle liner is discarded, the bag may be fitted with a pull strip 140. To accommodate the pull strip 140, referring to fig. 2, the first top edge 120 of the first sidewall 102 can be folded toward the inner volume 106 and attached to the sidewall inner surface to form a first hem 142. Similarly, the second top edge 122 of the second sidewall 104 can be similarly folded toward the interior volume and attached to the second sidewall to form a second hem 144. The pull strip 140, which may be fixedly attached at the first and second side edges 110, 112, passes loosely through the first and second hems 142, 144 along the first and second top edges 120, 122. To provide access to the pull strip 140, first and second notches 146, 148 may be provided through the respective first and second top edges 120, 122. Pulling the pull strip 140 through the notches 146, 148 tightens the top edges 120, 122, closing the opening 124. Depending on the circumstances, a pull strip closure may be used with any of the embodiments described herein.

Referring again to the embodiment of fig. 4 and 5, other closure mechanisms, such as tie flaps, may be used to close the opening 224 of the bag. The tie sheets 260, 262 may be extensions of the top edges 220, 222 of the respective sidewalls 202, 204, which may be tied together when the bag 200 is removed from the basket and discarded. Depending on the circumstances, the tie-sheet closure can be used with any of the embodiments described herein. In addition to tie-down tabs and pull-out straps, other suitable closure mechanisms may include twist-tie loops (twist ties) and mechanical clips. Furthermore, to secure the bag to the trash can, an elastic band may be attached around the foldable bag opening, tightening around the edge of the trash can. In those embodiments where the bag is used in applications other than trash can liners, other suitable closure mechanisms can include interlocking fastening strips, low tack or peelable adhesives, or various over-turned (flod-top) structures.

In other embodiments, the thermoplastic sidewall of the bag may be configured to stretch or deform to accommodate bulky or large objects and/or to further provide puncture or rupture resistance. For example, referring again to FIG. 1, the thermoplastic sheets comprising the sidewalls 102, 104 can be formed with a plurality of patterns that allow the sidewalls to stretch or deform. U.S. patent nos. 6,139,185; U.S. publication No. 2004/0134923; U.S. Pat. Nos. 6,394,651, 6,394,652; U.S. patent nos. 6,150,647; U.S. patent nos. 6,513,975; or U.S. patent No.6,695,476, which is incorporated herein by reference in its entirety, discloses examples of such patterns and similar features.

Referring to fig. 6 and 7, each pattern 170 may form a "deformable mesh structure under tension", which may include a plurality of first regions 172 and a plurality of second regions 174. The second region 174 may be formed as a rib-like element in the sidewall material such that the first and second regions come together or contract in the untensioned state shown in fig. 6. When a pulling force is applied, as indicated by arrow 176 in fig. 7, the second region 174 is able to straighten or geometrically deform such that the first and second regions 172, 174 can become substantially coplanar with one another. It will be appreciated that this will cause the pattern to stretch or elongate, thereby increasing the total area of the side wall. In addition to accommodating large objects, such a mesh structure that can deform under tension provides shock absorption when an object is suddenly thrown or dropped into a bag.

The bag with the reinforcement member can be manufactured in a number of different ways. To minimize the added cost of the bag, the manufacture can be done in a high speed automated process. For example, referring to FIG. 8, a schematic diagram of an embodiment for high speed automated bag manufacturing is shown wherein reinforcement strips are disposed inside the bag; i.e. in the inner volume. In the illustrated embodiment, manufacturing may begin with a first step 300 of unwinding a web 302 of thermoplastic sheet material from a spool 304 and feeding the web in a machine direction 306. The unwound web 302 may have a rectangular profile including a width 308 perpendicular to the machine direction 306 measured between a first edge 310 and an opposing second edge 312. In other manufacturing environments, the web 302 may first be provided in other forms, or even extruded directly from a thermoplastic production process.

In a subsequent attachment step 320, a continuous strip 322 of thermoplastic material for forming the reinforcing strip may be fed towards the web 302 and may be redirected to be fed parallel and synchronously with the feeding of the web in the machine direction 306. The thermoplastic tape 322 may be first supplied from a spool, as with the web, or may be directly extruded. During redirection, the belt 322 may be positioned approximately half way between the first and second edges 310, 312 of the web 302 by the roller 324.

To facilitate attachment of the belt 322 to the web 302, the roller 324 may be heated. Heating the strip of thermoplastic material 322 may transform the strip material into a phase or physical state that makes it more susceptible to bonding to the web of thermoplastic material 302. In addition to using heated rollers 324, hot air may be directed onto the web and/or belt. In addition, in some embodiments where the belt 322 is extruded just prior to attachment to the web, the belt material may be maintained at a sufficiently high temperature to be easily bonded to the web.

In a subsequent folding step 330, the web 302 may be folded about its width 308 in line with the machine direction 306 to provide adjacent first and second folded halves 332, 334. The folding step 330 may move the second edge 312 adjacent to the first edge 310 such that both edges correspond to the open top edge of the finished bag. The half width portion of the web 302 (with the strip 322 attached thereto) corresponds to the reinforced bottom edge portion of the finished bag, which can be moved in a direction parallel to the machine direction 306. In addition, the superposed halves 332, 334 of the web 302 correspond to the first and second side walls of the finished bag.

Additional processing steps may be added to make the finished bag. For example, in the edge processing step 340, heat seals 342 may be formed by heat seal device 344 along the width of the folded web 302 perpendicular to the machine direction 306. In the perforation step 350, the heat seal 342 may be perforated by, for example, a perforation knife 352. The folded, sealed and perforated web may then be wound into a spool 360 for dispensing. It should be appreciated that the finished bag 362 may be unwound and separated from the spool 360 for use as a trash receptacle liner. In another embodiment, the web may be folded one or more times prior to the perforating step. In another embodiment, the web 302 may be cut into individual bags after the side seals 342. The web may be folded one or more times before the cutting step. The individual bags may be staggered and may be wound on a spool.

Referring to fig. 9 and 10, another embodiment of an automated manufacturing process for making bags with internal reinforcing strips is shown. In the illustrated process, the thermoplastic web 400 may be folded into adjacent first and second halves 402, 404 that are connected at a common bottom edge 414. The process feeds the folded web 400 in the machine direction 406 toward the expansion attachment assembly 420 so that the bottom edge 414 may be parallel to the machine direction. The expansion assembly 420 may include suspended rigid expansion rods 422 that may extend between the first and second web halves 402, 404 proximate the bottom edge 414, thereby separating the halves. Prior to expanding the assembly 420, a continuous strip of thermoplastic material 430 may be directed perpendicular to the machine direction 406 between the first and second web halves 402, 404. The belt 430 may be folded lengthwise to provide a first belt half 432 and a corresponding second belt half 434. The folded strip 430 may be reoriented adjacent the bottom edge 414 extending parallel to the machine direction by appropriately arranged rollers 424 or similar devices. The extension rods 422 may also separate the first and second belt halves 432, 434 of the folded belt 430 from each other and adjacent the respective first and second web halves 402, 404 of the web 400.

To attach the first and second belt halves 432, 434 of the folded belt to the first and second web halves 402, 404 of the web, two opposing rollers 440 may be disposed behind the spreader bar 422 in the machine direction 406. The roll 440 may be heated and/or hot air 444 may be applied to the web and/or belt. The roller 440 may be positioned near the bottom edge 414 of the web 400. Vertically arranged separation plates 442 may be located between the rollers 440. The separation plate 442 may be suspended between the first and second web halves 402, 404 of the folded web 400 near the common bottom edge 414. The separation plate 442 may be narrower in width than the extension rod 422. Thus, as the web 400 passes through the extension bar 422 in the machine direction 406, the first and second web halves 402, 404 move toward each other, but are still separated by the separation plate 442.

At this stage, it should be appreciated that the first web half 402 and the adjacent first belt half 432 are both guided between the heated roller 440 and the separation plate 442, while the second web half 404 and the adjacent second belt half 434 are guided between the opposite roller 440 and the separation plate 442. The roll 440 may be heated and/or hot air 444 may be applied to the web and/or belt. The first web half 402 and the first belt half 432 may be welded together, while the second web half 404 and the second belt half 434 may be welded together. As the separation plate 442, the connected first web half and belt half, and the connected second web half and belt half may remain separate and connected by the common bottom edge 414. The web 400 may be directed along the machine direction 406 to further processing steps to provide finished bags.

Referring to fig. 11, another embodiment of a manufacturing process for applying the outer reinforcing tape 530 near the bottom edge 514 of the plastic bag is schematically shown. According to the process shown in fig. 11, the continuous web 500 may be folded into first and second web halves 502, 504 connected along a common bottom edge 514. Initially, the process may direct the folded web 500 in a machine direction 506. The bottom edge 514 may be parallel to the machine direction 506. The unfolded strip of reinforcement material 530 may be oriented to move parallel to the folded web 500 along the machine direction 506, near the bottom edge. The orientation of the reinforcing strip may be accomplished by reorienting members 520, such as rollers, pulling nip rollers (pull-nips) or suitably arranged stationary rod-like members. As shown in fig. 12, the unfolded reinforcing strip 530 may be moved parallel and adjacent to the second web half 504. A portion of the reinforcement strip 530 may extend beyond the bottom edge 514.

The reinforcing strip 530 may be folded into first and second strip halves 532, 534 in the machine direction 506 such that the strip portion previously extending beyond the bottom edge 514 may be folded onto the bottom edge. Folding of the reinforcing strip 530 may be accomplished by another reorienting member 522, such as a roller, a pulling nip roller, or a rigid rod. Referring to fig. 13, the portion of the web 500 near the bottom edge 514 may be positioned between the outer folded reinforcing strips 530 such that the first web half 502 is adjacent to the first strip half 532 and the second web half 504 is adjacent to the second strip half 534.

To attach the stabilizing strip 530 to the web 500, the strip and web may be guided in the machine direction 506 between a pair of opposing rollers 540. The rollers 540 may be heated and/or hot air 544 may be applied to the web and/or belt. As shown in fig. 14, a roller 540 may be disposed proximate the bottom edge 514 of the web 500 to press the first and second belt halves 532, 534 toward the respective first and second web halves 502, 504. The first and second belt halves 532, 534 may be welded to the respective first and second web halves 502, 504. To avoid welding the web halves 502, 504 together, a separation plate 542 may be suspended between the web halves and the roller 540. The web 500 with the reinforcing strip 530 externally attached to the bottom edge 514 may then be moved in the machine direction 506 for additional processing.

Referring to FIG. 15, another embodiment of a manufacturing process for making thermoplastic bags with reinforcing components from a plurality of separate webs of material is shown. According to the process, a first thermoplastic web 602 may be unwound from a web or sheet spool 600 and directed in a machine direction 606. The web 602 may have a width 608 defined between first and second edges 604, 605 perpendicular to the machine direction 606. To provide a portion of the reinforcement member, a strip 610 of thermoplastic reinforcement material that is narrower in width than the first web may be directed toward the first web and redirected to move adjacent the second edge 605 in a machine direction 606 that is parallel to the second edge 605. The first belt 610 may be attached to the first web 602 by, for example, a pair of rollers 612, which may be heated, and/or hot air may be applied to the web and/or the belt. In the illustrated embodiment, the rollers 612 may be arranged to accomplish both the redirection and the attachment of the belt to the web.

The second web 622 of thermoplastic material may be unwound from the second material spool 620 and directed toward the first web 602. The second web may have a width 628 defined between the first and second edges 624, 625. To provide another portion of the stiffening feature, the second belt 630 may be directed toward the second web 622 and redirected to move parallel and adjacent to the second edge 625. The reorientation of the belt 630 may be accomplished by a pair of rollers 632, suitably arranged. The belt 630 may be attached to the second web 622 by, for example, the pair of rollers 632, which may be heated, and/or hot air 634 may be applied to the web and/or the belt.

The second web 622 with the second belt 630 attached thereto may be redirected by a pair of rollers 640 to move parallel and adjacent to the first web 602 in the machine direction 606. The first and second webs 602, 622 may be oriented such that the first and second bands 610, 630 may face each other. To attach the webs 602, 622 together, the webs may be guided between a pair of rollers 642, which may be arranged near the second edges 605, 625 of the respective webs. The roll 642 may be heated and/or hot air 644 may be applied to the web 602 and/or the web 622. The second edges 605, 625 of the web and the respective portions of the first and second strips 610, 630 may be welded together along the second edges 605, 625. Referring to fig. 16, the first and second webs 602, 622 may be joined along second edges 605, 625, and the remainder of the webs may be separable.

The joined webs 602, 622 may be fed in the machine direction 606 for further processing to produce finished bags. For example, the webs 602, 622 may be joined together by intermittent heat seals 650 formed by heat seal 652 along the web widths 608, 628. The web may be perforated along the heat seal 650 by a perforation device 654. The finished bag 660 may be separated along perforations 655. In another embodiment, the web may be cut into individual bags after side sealing, and the bags may be interleaved and wound on a spool, as described herein. As described herein, the web may be folded one or more times prior to the perforating or cutting step. The finished bag 660 can include opposing first and second sidewalls 662, 664 that define an interior volume 666. It should be appreciated that the opposing first and second sidewalls 662, 664 are the final products of the first and second webs 602, 622. Likewise, the bottom edge 668 of the finished bag 660 may be reinforced by the final product of the first and second strips 610, 630.

In another embodiment, the process shown in fig. 15 and the bag shown in fig. 15 may be modified such that the first and second belts 610, 630 may be positioned outside of the first and second webs 602, 622 and sidewalls 662, 664.

Referring now to fig. 17-19, another embodiment of steps or stages in an automated manufacturing environment is shown in which reinforcement strips may be placed next to and may be attached to a flexible thermoplastic web or sheet to be processed into finished bags. The web 700 (which may be folded into first and second web halves 702, 704 placed adjacent to each other) may be positioned and directed along the machine direction 706 toward the expanded frame 720. An expansion frame 720 (which may be made of various plastic or metal rods and plates attached together) may be disposed between the folded web 700 to partially separate the folded web halves 702, 704 fed along the machine direction 706. The extension frame 720 may include a backplane 722. When the first and second web halves 702, 704 are separated by the expanding frame 720, the crease 714 connecting the web halves and corresponding to the bottom edge of the finished bag may move toward the panel 722 and move adjacently along the panel 722. As shown in fig. 18, the bottom plate 722 may form a portion of the web halves 702, 704 into an attachment 723. The attachment portion 723 is relatively flat as it passes over the base plate 722.

Referring to fig. 17-19, a strip 730 of reinforcing material may be directed toward the upstream end of the expanded frame 720, wherein the strip may be positioned proximate to the attachment 723 of the web halves 702, 704. The belt 730 may also be directed downward toward the bottom plate 722 of the frame 720, where it may be aligned with the fold 714 and the attachment 723, and redirected to move parallel to the machine direction 706, the fold 714, and the attachment 723. Thus, in the embodiment shown in fig. 18 and 19, the strap 730 may be located between the attachment portion 723 and the backplane 722 of the expansion frame 720.

To attach the reinforcing strip 730 and the web 700, the expansion frame 720 may include a roller 724. The roller 724 may be supported by the bottom plate 722 and disposed downstream thereof in the machine direction 706 through the bottom plate 722, where the belt is initially guided between the separated web halves 702, 704. The roller 724 may be heated. A second roller 726 may be located below the frame 720 and opposite the first roller 724. The roller 726 may be heated. The opposing rollers 724, 726 may be arranged perpendicular to the machine direction 706. The hot air 727 may be applied to the belt 730 and/or the web 700. Thus, when the rollers 724, 726 are heated, and/or hot air is activated, the web material 700 and the stabilizing strip 730 may be bonded or heat sealed together. In other embodiments, roller 724 may not be used, and roller 726 may press against plate 722 through stiffener tape 730 and web 700 to attach the tape to the web. In another embodiment, the hot air 727 may not be used and the rollers may be heated. In another embodiment, hot air may be used and the rollers may not be heated. In other embodiments, the process equipment used to attach the web 700 to the belt 730 may be located downstream of the folding frame 720 in the machine direction.

Referring to fig. 20-22, another embodiment of the steps or stages for placing the soft thermoplastic web 800 and the strip 830 of thermoplastic reinforcing material together in a high speed manufacturing environment is shown. The initially provided web 800 may be folded lengthwise into adjacent first and second web halves 802, 804, which may be directed for movement along a machine direction 806.

To separate adjacent web halves 802, 804, a V-shaped plate 820 made of a material such as metal or plastic may be disposed between the first and second web halves, with the angled apex 821 of the V-shaped plate against the machine direction 806. V-shaped plate 820 may be made of any suitable material, such as metal or plastic, and may include angled first and second legs 822, 824, which may be reinforced by a support bar 826 disposed transverse to the "V". V-shaped plate 820 may partially separate adjacent first and second web halves 802, 804 as web 800 is directed in machine direction 806. In addition, when web half separation occurs, bottom fold 814 connecting the web halves and corresponding to the bottom edge of the finished bag may move toward and extend adjacently along the bottom of V-shaped plate 820. As shown in fig. 21, V-shaped plate 820 may form a portion of web halves 802, 804 into attachment 823. The attachment portion 823 is flat due to its penetration through the V-shaped plate 820.

Likewise, after separation of the web halves, a strip of reinforcing material 830 may be directed toward the V-plate 820 and down between the angled legs 822, 824 to a location proximate the crease 814 and attachment 823 of the web 800. The belt 830 may be reoriented by, for example, a bar or roller 828 to extend parallel to the machine direction 806 and parallel and adjacent to the fold 814 and attachment 823. The belt 830 may actually be attached to the web 800 within the extension of the V-plate or downstream. The belt 830 may be attached to the web 800 using heated rollers and/or hot air as described herein. After passing through V-shaped plate 820, first and second web halves 802, 804 may be folded adjacent to each other about crease 814.

In addition to the step or stage of positioning and/or attaching the reinforcing strips to the thermoplastic web, the manufacturing environment may include any number of additional processing steps or stages for manufacturing the finished bag. Referring to fig. 23, a number of additional processing steps are schematically shown, such as: (1) the web is unwound 900; (2) attaching a withdrawal tape 910; (3) forming the pattern 920 to provide a mesh structure that is deformable under tension as described with reference to fig. 5 and 6; and (4) side sealing, perforating or cutting 930. The tape positioning and/or attaching step 940 may be accomplished between any of the foregoing processing steps, or between other processing steps as the case may be, or may be dispersed among different processing steps as the case may be, for example, tape positioning may be performed before the tape drawing step and tape attachment may be performed after the tape drawing step.

Referring to fig. 24, a thermoplastic bag 1000 is shown wherein the step of positioning and attaching the reinforcing strip may be performed prior to the step of forming a mesh structure that is deformable under tension. In this embodiment, a reinforcing strip 1030 may be disposed along the closed bottom edge 1014 of the bag 1000 and may extend between the first and second edges 1010, 1012. The open top edge 1016 (located opposite the closed bottom edge 1014) of the bag 1000 may be fitted with a drawstring 1040 accessible through the notch 1042 for cinching closed the open top edge.

After the reinforcing strip 1030 and the pull strip 1040 have been attached, the bag may be subjected to a forming step in which a pattern 1070 may be formed on the opposing first and second sidewalls 1002, 1004. To prevent interference with the draw belts and closed bottom edge, and to obtain the possibility of pinching the bag with the free edge of the rotating roll and guiding it through the processing equipment, the pattern 1070 may be spaced from the open top edge 1016 and closed bottom edge 1014. Thus, these parts of the bag are not formed and the material of these locations will not be secured to each other. For example, the uppermost region of pattern 1070 may be offset from top edge 1016 by a distance 1072. Distance 1072 may have a first range of about 1.5 inches (3.8 centimeters) to about 4 inches (10.2 centimeters), a second range of about 2 inches (5.1 centimeters) to about 3.25 inches (8.3 centimeters), and a third range of about 2.5 inches (6.4 centimeters) to about 3 inches (7.6 centimeters). In one embodiment, the distance 1072 may be 2.75 inches (7 centimeters). The lowermost region of the pattern may be offset from the closed bottom edge by a distance 1074. Distance 1074 may have a first range of about 0.5 inches (1.3 cm) to about 4 inches (10.2 cm), a second range of about 1 inch (2.54 cm) to about 3 inches (7.6 cm), and a third range of about 1.5 inches (3.8 cm) to about 2.5 inches (6.4 cm). In one embodiment, the distance 1074 may be 1.75 inches (4.4 centimeters). The pouch may have a height 1076 measured between the top and bottom edges 1016, 1014. The height 1076 may have a first range of about 18 inches (45.7 centimeters) to about 48 inches (121.9 centimeters), a second range of about 22 inches (55.9 centimeters) to about 38 inches (96.5 centimeters), and a third range of about 24 inches (61 centimeters) to about 28 inches (71.1 centimeters). In one embodiment, the height 1076 may be 25.13 inches (63.8 centimeters). Pattern 1070 may have a height 1078. The height 1078 may have a first range of about 9.8 inches (24.9 centimeters) to about 45.8 inches (116.3 centimeters), a second range of about 13.4 inches (34 centimeters) to about 31.4 inches (79.8 centimeters), and a third range of about 17 inches (43.2 centimeters) to about 24.2 inches (61.5 centimeters). In one embodiment, the height 1078 may be 20.6 inches (52.3 centimeters).

The reinforcing strip 1030 attached to the bag 1000 may have a height 1080 such that the reinforcing strip extends from the bottom edge 1014 towards the top edge 1016. The height 1080 may have a first range of about 1 inch (2.54 centimeters) to about 10 inches (25.4 centimeters), a second range of about 2 inches (5.1 centimeters) to about 8 inches (20.3 centimeters), and a third range of about 4 inches (10.2 centimeters) to about 6 inches (15.2 centimeters). In one embodiment, the height 1080 may be 5 inches (12.7 centimeters). For bags in which the lowermost region of the pattern 1070 is offset from the bottom edge 1014, the pattern and the reinforcement strip 1030 partially overlap by a distance 1082. Distance 1082 may have a first range of about 0 inches (0 cm) to about 9.5 inches (24.13 cm), a second range of about 1 inch (2.54 cm) to about 7 inches (17.78 cm), and a third range of about 1.5 inches (3.8 cm) to about 3.5 inches (8.9 cm). In one embodiment, distance 1082 may be 3.25 inches (8.3 centimeters). The overlap of the pattern with the reinforcement strip portions, where the reinforcement strip blends visually into the sidewall, may provide a visually pleasing appearance.

Referring to fig. 25, a cost effective way of manufacturing the sidewall web and the reinforcement strip from the same sheet of thermoplastic material is shown. An initial continuous sheet 1100 of soft thermoplastic material may be directed in a machine direction 1102. The sheet 1100 may have an initial width 1108 measured perpendicular to the machine direction 1102 between a first side edge 1104 and a second side edge 1106. The width 1108 may have a first range of about 19 inches (48.3 centimeters) to about 58 inches (147.3 centimeters), a second range of about 24 inches (61 centimeters) to about 46 inches (116.8 centimeters), and a third range of about 28 inches (71.1 centimeters) to about 34 inches (86.4 centimeters). In one embodiment, the width 1108 may be 32.56 inches (82.7 centimeters). The sheet 1100 may be directed through a cutting device 1110 that slits or cuts the sheet along a machine direction 1102. The cuts may be positioned closer to the first edge 1104 than the second edge 1106 along the width of the sheet so that the sheet may be separated into a belt portion 1120 and a web portion 1130. The strip portion 1120 may have a width 1122 and the web portion 1130 may have a width 1132. The width 1122 may have a first range of about 1 inch (2.54 centimeters) to about 10 inches (25.4 centimeters), a second range of about 2 inches (5.1 centimeters) to about 8 inches (20.3 centimeters), and a third range of about 4 inches (10.2 centimeters) to about 6 inches (15.2 centimeters). In one embodiment, width 1122 may be 5 inches (12.7 centimeters). The width 1132 may have a first range of about 19 inches (48.3 centimeters) to about 50 inches (127 centimeters), a second range of about 23 inches (58.4 centimeters) to about 40 inches (101.6 centimeters), and a third range of about 25 inches (63.5 centimeters) to about 30 inches (76.2 centimeters). In one embodiment, the width 1132 may be 27.56 inches (70 centimeters). The separable belt 1120 can be wound on a first spool 1124 and the web can be wound on a separate second spool 1134. It should be appreciated that the first spool provides the reinforcement strip material and the second spool provides the sidewall material.

Referring to fig. 26 and 27, another embodiment of the invention is shown wherein the thermoplastic bag has reinforced bottom edges. The reinforced bottom edge may be provided by making the bag from a thermoplastic web or sheet having varying thickness. For example, referring to fig. 26, a bag 1200 may be made from a single web 1201 of soft thermoplastic material that may be folded along a closed bottom edge 1214 to provide a first sidewall 1202 and an opposing second sidewall 1204. The opposing first and second sidewalls 1202, 1204 provide an interior volume 1206 for receiving an item. To access the interior volume, the top edges 1220, 1222 of the respective sidewalls 1202, 1204 opposite the closed bottom edge 1214 can remain unconnected to provide an opening 1224 opposite the closed bottom edge 1214.

To reinforce the bag 1200, the web material 1201 providing the first and second sidewalls 1202, 1204 may have a varying thickness. For example, the web material has a material thickness, represented by thickness 1230, near bottom edge 1214 that is greater than the material thickness, represented by thickness 1232, near top edges 1220, 1222. The first thickness 1230 may have a first range of about 0.0009 inches (0.0023 cm) to about 0.0015 inches (0.0038 cm), a second range of about 0.00095 inches (0.0024 cm) to about 0.0014 inches (0.0036 cm), and a third range of about 0.001 inches (0.0025 cm) to about 0.0013 inches (0.0033 cm). In one embodiment, the thickness 1230 may be 0.0012 inches (0.0030 cm). Thickness 1232 may have a first range of about 0.0005 inches (0.0013 cm) to about 0.0014 inches (0.0036 cm), a second range of about 0.0006 inches (0.0015 cm) to about 0.001 inches (0.0025 cm), and a third range of about 0.0007 inches (0.0018 cm) to about 0.00085 inches (0.0021 cm). In one embodiment, the thickness 1232 may be about 0.0008 inches (0.0020 cm). Thus, bottom edge 1214 is reinforced with more web material, and is more resistant to cracking and/or puncturing.

Referring to fig. 27, another embodiment of a reinforced plastic bag 1300 made from a web having a varying thickness is shown. The bag 1300 may be made from a first sidewall 1302 of a thermoplastic material and a separate, opposing second sidewall 1304 of a similar material. The first and second sidewalls 1302, 1304 can be joined along a closed bottom edge 1314 by, for example, heat sealing. Thus, the opposing sidewalls 1302, 1304 define an interior volume 1306 for receiving items for storage. To access the interior volume 1306, the top edges 1320, 1322 of the respective sidewalls 1302, 1304 remain unconnected to provide the opening 1324. To reinforce the bag, the material of the first sidewall 1302 has a greater thickness proximate the closed bottom edge 1314 than proximate the open top edge 1320. The thickness 1330 proximate the bottom edge 1314 may have a first range of about 0.0009 inches (0.0023 cm) to about 0.0015 inches (0.0038 cm), a second range of about 0.00095 inches (0.0024 cm) to about 0.0014 inches (0.0036 cm), and a third range of about 0.001 inches (0.0025 cm) to about 0.0013 inches (0.0033 cm). In one embodiment, the thickness 1330 may be 0.0012 inches (0.0030 centimeters). The thickness 1332 proximate the top edge 1320 may have a first range of about 0.0005 inches (0.0013 cm) to about 0.0014 inches (0.0036 cm), a second range of about 0.0006 inches (0.0015 cm) to about 0.001 inches (0.0025 cm), and a third range of about 0.0007 inches (0.0018 cm) to about 0.00085 inches (0.0020 cm). In one embodiment, thickness 1332 may be approximately 0.0008 inches (0.0020 cm). The web of material forming the second sidewall 1304 may be similarly shaped such that the bottom edge 1314 is reinforced with more web material.

The web material having varying thicknesses may be formed in a variety of suitable ways. For example, the web extrusion process may be modified such that the extrusion die comprises a slot having a varying width. In another example, the additional web material may be coextruded with the primary web material such that the materials are bonded together. Another example is to blow extrude a web or sheet of thermoplastic material and then vary the cooling rate of the blown sheet in different sections. A non-uniform cooling rate will result in different portions of the sheet having different thicknesses. Other suitable methods of varying the thickness of the thermoplastic sheet may be used.

In addition to heated rollers and/or heated air, other methods for attaching the stabilizing strip to the web may be used as appropriate, such as ultrasonic techniques, adhesives, and/or mechanical modifications, such as forming a pattern as described herein.

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) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," 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 a 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.

Exemplary embodiments of the present invention are described herein. Variations of those 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.

Claims (15)

1. A thermoplastic bag, comprising:

a first sidewall made of a flexible thermoplastic web;

a second sidewall made of a flexible thermoplastic web superposed with and joined to the first sidewall to provide an interior volume, the first and second sidewalls joined along a first side edge, an opposing second side edge, and a closed bottom edge, the first and second sidewalls being unconnected along their respective top edges to define an opening opposite the bottom edge for accessing the interior volume;

wherein the bag comprises a reinforcing member disposed along the closed bottom edge.

2. The thermoplastic bag of claim 1, wherein the reinforcement member is a reinforcement strip attached along the bottom edge.

3. The thermoplastic bag of claim 2, wherein the reinforcing strip extends partially from the bottom edge toward the opening adjacent the first and second sidewalls.

4. The thermoplastic bag of claim 2, wherein the reinforcing strip is attached to the bottom edge by heat between the reinforcing strip and respective portions of the first and second sidewalls.

5. The thermoplastic bag of claim 2, wherein the reinforcing strip is folded along the bottom edge and adjacent to respective outer surfaces of the first and second sidewalls.

6. The thermoplastic bag of claim 2, wherein the reinforcing strip is inserted into the interior volume between the first and second sidewalls along the bottom edge.

7. The thermoplastic bag of claim 2, wherein the reinforcing strip extends partially from the bottom edge toward the opening in a range of about 1 inch (2.54 cm) to about 10 inches (25.4 cm).

8. The thermoplastic bag of claim 1, wherein the first and second sidewalls each have a greater thickness proximate the bottom edge than proximate the top edge.

9. The thermoplastic bag of claim 8, wherein the first and second sidewalls have a thickness of about 0.0009 inch (0.0023 cm) to about 0.0015 inch (0.0038 cm) proximate the bottom edge and about 0.0005 inch (0.0013 cm) to about 0.0014 inch (0.0036 cm) proximate the top edge.

10. A method of making a thermoplastic bag comprising:

feeding a web of flexible thermoplastic material in a machine direction;

orienting a reinforcing strip of thermoplastic material adjacent to the web; and

attaching the reinforcing strip to the web.

11. The method of claim 11, wherein the feeding step further comprises:

the web is folded about a bottom edge parallel to the machine direction to provide a first side wall folded along the bottom edge and a second side wall superimposed.

12. The method of claim 11, wherein the orienting step further comprises:

orienting a reinforcing strip proximate the bottom edge and locally adjacent the first sidewall; and

the reinforcing strip is folded over the bottom edge to be locally adjacent the second sidewall.

13. The method of claim 11, wherein the orienting step further comprises:

separating the first and second sidewalls fed in the machine direction;

approximately folding the reinforcing strip in half about a fold line;

inserting a folded reinforcing strip between the first and second side walls such that the fold line is parallel and adjacent to the bottom edge;

attaching a first half of the folded reinforcement strip to the first sidewall;

attaching a second half of the folded reinforcement strip to the second sidewall.

14. The method of claim 10, wherein the orienting step further comprises:

positioning a reinforcing strip substantially near the center of the web;

and after the attaching step: the web is folded about a bottom edge parallel to the machine direction to provide a first sidewall and a second sidewall that overlap connected along the bottom edge, such that a reinforcing strip located near the center of the web becomes the bottom edge.

15. The method of claim 10, further comprising:

extruding the web in cooperation with the feeding step; and

extruding the reinforcing strip in cooperation with the orienting step.