Abstract:
A woven laminated plastic bag having features that further prevent leakage of contents out of the bag, or infestation of organisms into the contents of the bag is provided. In various aspects the bag can be fabricated from woven polypropylene and/or polyethylene layer which can be laminated with a film layer, can form a pinch bottom bag, and can have one or both sides include graphics and/or printing. The bag can also provide a top end and/or a bottom end either or both of which provide a discrete area which may contain discrete graphics and/or printing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
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     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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     THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
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     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
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     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure generally relates to woven plastic bags, and more particularly to woven plastic bags with features that reduce the potential for leakage, breakage and infestation. 
     2. Background of the Invention 
     Conventional plastic bags of a wide variety of size and shape are used in various situations. Bulk materials, such as flour, sugar, rice, seed, animal feed, chemicals, powdered materials or the like, for example, typically have been packaged in woven plastic bags in the past. Pet food, bird seed and other products sold in retail stores typically have not been packaged in conventional woven plastic bags. Among other reasons for this, woven plastic bags were considered too rudimentary to be printed with high end graphics suitable for consumer type of packaging. In addition, the high speed requirements in the filling and packaging operations limited the use of the woven bags in these applications. 
     Laminated woven sacks (LWS) were developed using a woven polypropylene structure laminated to a bi-oriented polypropylene film (BOPP) that can be reverse printed with high end graphics suitable for consumer type of packaging. The LWS provides a stronger, more attractive bag than the more conventional multiwall bags used for that purpose over the last 20 years. Due to their tough strong structure, conventional LWS bags are typically sewn shut on both ends. These LWS recently met with success and have been successfully substituted for the conventional multiwall paper bags used in the pet food industry for many years. 
     One major drawback of the sewn LWS has been the closing of the bags at high speed filling lines, such as those for filling such bags with pet food. Experience has shown that sewing production lines are typically slower than the filling of the multiwall pinch bottom bags. Additionally, the sewn bags do not provide an aesthetically pleasing and useful clean display on the ends of the bags, thus making it difficult for consumers to identify or find a desired brand quickly when the bags are displayed on the shelves at the point of sale, such as when they are stacked on top of one another. In addition, the sewn ends required puncturing the plastic bags and thus result in a bag that is not sealed, leading to somewhat reduced shelf-life and possible infestation of the contents of the bag. 
     Woven plastic bags have been used and are conventional for certain applications. An example of a conventional woven plastic bag is provided in U.S. Pat. No. 4,373,979 (“the &#39;979 patent”), issued on Feb. 15, 1983. The &#39;979 patent describes the use of woven strips of highly longitudinally-oriented, high-density polyethylene or polypropylene in a bag construction in which the bag is formed from a seamed tube made of the woven plastic material. The seamed tube has gussets on either side and, when a portion is cut from the rest of the tube, a bag having two open, unsealed ends is provided. The &#39;979 patent describes the use of ultrasonic spot welds to seal portions of a bag made of such woven plastic strips, as opposed to sewing the seams of a bag or using a hot melt adhesive to seal the gusset forming pleat. The &#39;979 patent is hereby incorporated by reference herein. The &#39;979 patent purports to be an improvement for sealing a plastic bag. As noted in the &#39;979 patent, sewing one end tends to take longer, thus adding time to the manufacturing process. In addition, the sewn ends in a conventional bag tend to be a weak portion of the bag, and a likely location for rips, tearing, and subsequent loss of contents during storing, shipping and handling. In addition, such bags may not provide sufficient protection from infestation from vermin and/or insects. 
     Another example of plastic bags is disclosed in U.S. Patent Application Publication Number US 2010/0029455 A1 (“the &#39;455 publication”), published on Feb. 4, 2010, which describes production of web sections from a flexible web material that is provided with tear-off lines produced by laser beam processing at the distance of the length of the web sections to be formed. The tear-off lines weaken the flexible web material, but do not result in complete separation of the web sections from the web material, which occurs upon tearing the flexible web material. The &#39;455 publication is incorporated by reference herein. 
     More recently, some types of plastic bags have provided improvements in sealing the ends of the bags. For example, in U.S. Pat. No. 6,800,051 B2 (“the &#39;051 patent”), issued on Oct. 5, 2004, a process for sealing side fold sacks made of plastic film is described. According to the &#39;051 patent, a web of plastic tubular film is cut to provide a staggered detachment along a perforation so that one wall (e.g., the front wall) projects beyond the opposing wall (e.g., the back wall). The projecting portion of the first wall is then folded over and sealed to the opposing wall by means of a plastic adhesive such as a polyurethane adhesive or hot melt. The &#39;051 patent is hereby incorporated by reference herein. However, such bags involve plastic films, not woven plastic materials, and therefore are unable to handle the weight loads of conventional bulk bags made of paper and other materials. Such bags are useful for only certain lightweight contents, such as bread. 
     There are a variety of conventional ways of providing for reusable openings in bags. For example, U.S. Pat. No. 6,478,465 B1 (“the &#39;465 patent”), issued Nov. 12, 2002, describes a peelable opening in a multiwall, pinched bottom open mouth bag construction. The &#39;465 patent also describes the use of an adhesive layer that can be used so that the bag opening is reclosable. The &#39;465 patent is hereby incorporated by reference herein. 
     In other types of conventional plastic bags, such as those used in retail and grocery stores, the use of weakened portion provided by one or more perforations in the plastic bag wall is known. A number of approaches have been taken in connection with such bags, including those shown in U.S. Pat. No. 5,188,235 (the &#39;235 patent), issued Feb. 23, 1993, as well as in U.S. Published Patent Application No. 2005/0087542 A1 (the &#39;542 application), published Apr. 28, 2005, U.S. Pat. No. 5,979,655 (the &#39;655 patent), issued Nov. 9, 1999, and U.S. Published Patent Application No. 2006/0072856 (the &#39;856 application), issued Apr. 6, 2006. However, none of these bags are woven bags, let alone bags with multiple layers. The &#39;235 patent, the &#39;655 patent, the &#39;542 application, and the &#39;856 application are hereby incorporated by reference. 
     Newly developed pinch laminated woven sacks overcome these drawbacks in the filling and closing operations while allowing an attractive graphic display of the bags&#39; ends at the retail outlet and also providing a strong, durable bag which remains sealed. However, such bags still remain susceptible to leakage, breakage and infestation at both ends of the seam and in the area along the top and bottom of the gussets. There is a need for such a pinch bottom laminated woven sack that includes one or more feature(s) that prevent leakage, breakage and/or infestation at both ends of the seam and in the area along the top and bottom of the gussets. Moreover, the bag needs to be strong enough to avoid leakage, breakage or infestation, which can begin with a small opening or crack that then gets larger over time, such as with additional forces or movement of the bag. At the same time, however, it is desirable to avoid “solutions’ that require additional plastic material, additional adhesive material, such as for extra strength, or that slow the speed of manufacture. Such “solutions” increase the cost of the bag. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides woven plastic bags comprising one or more features that prevent leakage and/or infestation at both ends of the seam and in the area along the top and bottom of the gussets. 
     The present disclosure provides bags that have certain sections that are separated by an angled portion or edge, a curved portion or edge, or a combination thereof, and/or bags that comprise a cut-out and corresponding tab at opposing ends of the bag proximal to the portions of the back wall that form the seam. In one embodiment, the bag comprising a front wall, a back wall having a first portion and a second portion, a first side wall having a first portion proximal to the first portion of the back wall and a second portion proximal to the front wall, a second side wall having a first portion proximal to the second portion of the back wall and a second portion proximal to the front wall, an interior surface, an exterior surface, a top end, a bottom end, a first layer and a second layer, each of the front wall, back wall, first side wall and second side wall having an interior surface, an exterior surface, a top end and a bottom end, wherein the first layer comprises a woven polymer and the second layer comprises a polymer or paper attached to the first layer, wherein the back wall projects further than the top end of the first portion of the first side wall and the top end of the first portion of the second side wall, the top end of the first portion of the first side wall and the top end of the first portion of the second side wall projects further than the top end of the second portion of the first side wall and the top end of the second portion of the second side wall, and the top end of the second portion of the first side wall and the top end of the second portion of the second side wall projects further than the top end of the front wall, wherein at least a portion of the bottom end of the front wall projects further than the bottom end of the second portion of the first side wall and the bottom end of the second portion of the second side wall, the bottom end of the second portion of the first side wall and the bottom end of the second portion of the second side wall project further than the bottom end of the first portion of the first side wall and the bottom end of the first portion of the second side wall, and the bottom end of the first portion of the first side wall and the bottom end of the first portion of the second side wall project further than the bottom end of the back wall, and wherein the top end of the first portion of the back wall and the top end of the first portion of the first side wall, the top end of the first portion of the first side wall and the top end of the second portion of the first side wall, the top end of the second portion of the first side wall and the top end of the front wall, the top end of the front wall and the top end of the second portion of the second side wall, the top end of the second portion of the second side wall and the top end of the first portion of the second side wall, the top portion of the first portion of the second side wall and the top portion of the second portion of the back wall, the bottom end of the first portion of the back wall and the bottom end of the first section of the first side wall, the bottom end of the first portion of the first side wall and the bottom end of the second portion of the first side wall, the bottom end of the second portion of the first side wall and the bottom end of the front wall, the bottom end of the front wall and the bottom end of the second portion of the second side wall, the bottom end of the second portion of the second side wall and the bottom end of the first portion of the second side wall, and the bottom end of the first portion of the second side wall and the bottom end of the second portion of the back wall are separated by an angled edge or portion, a curved edge or portion, or a combination thereof, and wherein the top end of the second portion of the back wall comprises a cut-out and the bottom end of the second portion of the back wall comprises a corresponding tab. 
     In certain embodiments the angled edge or portion is between about 15° and about 75°, or between about 30° and about 60°, with respect to the top end of the front wall. In other embodiments the angled edge or portion is about 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80° with respect to the top end of the front wall. In further embodiments the curved edge or portion is a radial edge or portion, an elliptical edge or portion, a parabolic edge or portion, or a hyperbolic edge or portion. In additional embodiments the bag comprises an easy open or easy access feature, which in certain embodiments can comprise a weakened area. 
     The present disclosure additionally provides a bag comprising a front wall, a back wall, a first side wall, a second side wall, an interior surface, an exterior surface, a top end, a bottom end, a first layer and a second layer, each of the front wall, back wall, first side wall and second side wall having an interior surface, an exterior surface, a top end and a bottom end, wherein the first layer comprises a woven polymer and the second layer comprises a polymer or paper attached to the first layer, and wherein the bag comprises a weakened area located on the front wall of the bag, the first side wall of the bag and the back wall of the bag proximal the top end of the bag. In some embodiments the first layer comprises polypropylene, high density polyethylene, low density polyethylene, polyester, or any combination thereof. In other embodiments the second layer comprises a film. In still other embodiments the second layer comprises polypropylene, polyethylene, polyethylene terephthalate, polyamide, or any combination thereof or paper. In yet other embodiments the second layer comprises oriented polypropylene, biaxially-oriented polypropylene, oriented polyethylene, biaxially-oriented polyethylene, oriented polyethylene terephthalate, biaxially-oriented polyethylene terephthalate, oriented polyamide, biaxially-oriented polyamide, coated paper or any combination thereof. In further embodiments at least a portion of the second layer comprises a printed area thereon. In still further embodiments the first layer and second layer are laminated together. In yet further embodiments the first layer and second layer are laminated together using adhesive lamination or extrusion lamination. 
     In additional embodiments the weakened area comprises a plurality of perforations that penetrate through at least a portion of the front wall of the bag, the first side wall of the bag and the back wall of the bag. In some embodiments the plurality of perforations forms a line. In various embodiments the plurality of perforations forms a line that extends from any position on the front wall of the bag, for example about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 97%, about 98% or about 99% of a distance across the front wall of the bag, across the first side wall of the bag, to any position on the back wall of the bag, for example about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 97%, about 98% or about 99% of a distance across the back wall of the bag. In other embodiments the plurality of perforations forms a wave pattern. In further embodiments the plurality of perforations forms a zigzag pattern. In still further embodiments the weakened area comprises a deformation in least a portion of the front wall of the bag, the first side wall of the bag and the back wall of the bag. In yet further embodiments the weakened area further comprises a scoring mark. In certain embodiments each of the first layer and the second layer of the bag comprise a weakened portion. In still other embodiments the back wall of the bag comprises a seam. 
     In certain embodiments the top end of the back wall projects further than the top end of a portion of the first side wall proximal to the back wall and the top end of a portion of the second side wall proximal to the back wall, the top end of a portion of the first side wall proximal to the back wall and the top end of a portion of the second side wall proximal to the back wall projects further than the top end of a portion of the first side wall proximal to the front wall and the top end of a portion of the second side wall proximal to the front wall, and the top end of a portion of the first side wall proximal to the front wall and the top end of a portion of the second side wall proximal to the front wall projects further than the top end of the front wall. In other embodiments at least a portion of the bottom end of the front wall projects further than the bottom end of a portion of the first side wall proximal to the front wall and the bottom end of a portion of the second side wall proximal to the front wall, the bottom end of a portion of the first side wall proximal to the front wall and the bottom end of a portion of the second side wall proximal to the front wall project further than the bottom end of a portion of the first side wall proximal to the back wall and the bottom end of a portion of the second side wall proximal to the back wall, and the bottom end of a portion of the first side wall proximal to the back wall and the bottom end of a portion of the second side wall proximal to the back wall project further than the bottom end of the rear wall. In further embodiments the top end of a portion of the first side wall proximal to the back wall and the top end of a portion of the first side wall proximal to the front wall are separated by an angled cut, and the bottom end of a portion of the first side wall proximal to the back wall and the bottom end of a portion of the first side wall proximal to the front wall are separated by an angled cut. 
     In additional embodiments the portion of the bottom end of the front wall that projects further than the bottom end of the first side wall and the bottom end of the second side wall, and the portion of the bottom end of the first side wall and the bottom end of the second side wall that project further than the bottom end of the rear wall are sealed to the outer surface of the bottom end of the rear wall. In certain embodiments the bottom end of the bag is sealed using an adhesive sealing, heat sealing, adhesive lamination, extrusion lamination, stitching, ultrasonic energy, pressure, tape, or any combination thereof. In some embodiments the bottom end of the bag is sealed using adhesive-to-adhesive sealing or adhesive-to-bag sealing. In further embodiments the bottom end of the front wall, the bottom end of the first side wall, the bottom end of the rear wall and the bottom end of the second side wall each project the same distance. In still further embodiments at least a portion of a single fold of the bottom end of the bag is sealed to the outer surface of the front wall or the outer surface of the rear wall of the bag. In yet further embodiments at least a portion of a double fold of the bottom end of the bag is sealed to the outer surface of the front wall or the outer surface of the rear wall of the bag. 
     In other embodiments the top end of the front wall, the top end of the first side wall, the top end of the rear wall and the top end of the second side wall each project the same distance. In certain embodiments at least a portion of the bottom end of the front wall projects further than the bottom end of a portion of the first side wall proximal to the front wall and the bottom end of a portion of the second side wall proximal to the front wall, the bottom end of a portion of the first side wall proximal to the front wall and the bottom end of a portion of the second side wall proximal to the front wall project further than the bottom end of a portion of the first side wall proximal to the back wall and the bottom end of a portion of the second side wall proximal to the back wall, and the bottom end of a portion of the first side wall proximal to the back wall and the bottom end of a portion of the second side wall proximal to the back wall project further than the bottom end of the rear wall. In still other embodiments the portion of the bottom end of the front wall that projects further than the bottom end of the first side wall and the bottom end of the second side wall, and the portion of the bottom end of the first side wall and the bottom end of the second side wall that project further than the bottom end of the rear wall are sealed to the outer surface of the bottom end of the rear wall. In additional embodiments the bottom end of the front wall, the bottom end of the first side wall, the bottom end of the rear wall and the bottom end of the second side wall each project the same distance. In certain embodiments the top end and the bottom end of the bag are sealed, and wherein the bag comprises at least ten pounds by weight of a filling material. 
     In some embodiments the bag further comprises a third layer comprising a polymer between the first layer and the second layer. In certain embodiments the third layer comprises a woven polymer. In other embodiments the third layer comprises polypropylene, high density polyethylene, low density polyethylene, polyester, or any combination thereof. In further embodiments the third layer comprises a polymeric film. In additional embodiments the third layer comprises polypropylene, polyethylene, polyethylene terephthalate, polyamide, or any combination thereof. In still other embodiments each of the first layer, the second layer and the third layer of the bag comprise a weakened portion. 
     In further embodiments the bag comprises printing on the front wall, the first side wall, the back wall, the second side wall, the first end, the second end, or any combination thereof. In still further embodiments at least portions of the exterior surfaces of each of the front wall and the back wall comprise a plurality of discrete areas further comprising printing thereon. In yet further embodiments a portion of the front wall and a portion of the back wall combine to form a discrete portion of the bag located at or near either the top end or the bottom end, wherein the discrete portion of the bag comprises printing thereon. 
     These and other objects of the invention will be apparent to those skilled in the art from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings are included to further demonstrate certain aspects and embodiments of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein. 
         FIG. 1  shows an outline of a step cut bag with a weakened area near the top end of the bag comprising a line of perforations extending from the front panel of the bag across the first side panel of the bag to the back panel of the bag according to one embodiment of the present disclosure. 
         FIG. 2  shows the top portion of the bag of  FIG. 1  after closing the top end of the bag. 
         FIG. 3  shows the first step in opening the closed bag from  FIG. 2 . 
         FIG. 4  shows the second step in opening the closed bag from  FIG. 2 . 
         FIG. 5  shows the third step in opening the closed bag from  FIG. 2 . 
         FIG. 6  shows the fourth step in opening the closed bag from  FIG. 2 . 
         FIG. 7  shows the top portion of the bag of  FIG. 1  after closing the top end of the bag and a location for optional application of adhesive to keep the top portion of the gusseted portion of the first side panel closed. 
         FIG. 8  shows an outline of a step cut bag with a weakened area near the top end of the bag comprising a line of perforations extending from the front panel of the bag across the first side panel of the bag to the back panel of the bag, and angled corners at the top and bottom of the portions of the first and second side panels on either side of the gusset fold, according to one embodiment of the present disclosure. 
         FIG. 9  shows an outline of a bag with a step cut top end and a flush cut bottom end, and a weakened area near the top end of the bag comprising a line of perforations extending from the front panel of the bag across the first side panel of the bag to the back panel of the bag according to one embodiment of the present disclosure. 
         FIG. 10  shows an outline of a bag with a flush cut top end and a flush cut bottom end, and a weakened area near the top end of the bag comprising a line of perforations extending from the front panel of the bag across the first side panel of the bag to the back panel of the bag according to one embodiment of the present disclosure. 
         FIG. 11  shows an outline of a bag with a step cut top end and a step cut bottom end, with an angled portion between the two sections of the side wall at both ends of the bag, and a tab at one end of the bag and a cut-out feature at the other end of the bag that extend into the seam. 
         FIG. 12  shows an outline of the top portion of a bag with a step cut top end, with radial (circular) portions between the back panel of the bag and the side wall, between the two sections of the side wall, and between the side wall and the front panel of the bag at the top end of the bag, and a cut-out feature at the top end of the bag that extends into the seam. 
         FIG. 13A  shows an outline of a portion of one end of a bag with a step cut end, corresponding to a mirror image of the region marked as “A” in  FIG. 11 , detailing an alternate embodiment with angled portions between the back panel of the bag and the side wall, between the two sections of the side wall, and between the side wall and the front panel of the bag, and a tab feature at one end of the bag that extends into the seam.  FIG. 13B  shows an image of the top end of the bag depicted in  FIG. 13A  upon sealing the seam.  FIG. 13C  shows an image of the bottom end of the bag depicted in  FIG. 13A  upon sealing the seam. 
         FIG. 14A  shows an outline of a portion of one end of a bag with a step cut end, corresponding to a mirror image of the region marked as “A” in  FIG. 11 , detailing an alternate embodiment with a combination of radial (circular) and angled portions between the back panel of the bag and the side wall, between the two sections of the side wall, and between the side wall and the front panel of the bag, and a tab feature at one end of the bag that extends into the seam.  FIG. 14B  shows an image of the top end of the bag depicted in  FIG. 14A  upon sealing the seam.  FIG. 14C  shows an image of the bottom end of the bag depicted in  FIG. 14A  upon sealing the seam. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a planar view of an embodiment of a substantially flat sheet of material from which a “step cut” bag  1  is to be formed is shown. Shown on the sheet are front wall  2 , rear wall  3 , seam  4 , first side wall  5  having gusset portion  6 , and second side wall  7  having gusset portion  8 . As shown in  FIG. 1 , the bag  1  has a first or top end  9  and a second or bottom end  10 , and thus each of the front wall  2 , rear wall  3 , first side wall  5  and second side wall  7  has a first or top end and a second or bottom end. It will be apparent, however, that the orientation of the bag ends  9  and  10  are unimportant and the “top” and “bottom” references are useful but may change depending upon the orientation from which one views the bag. Bag  1  is considered a “step cut” bag because the front wall  2 , the first side wall  5  and the second side wall  7 , and the rear wall  3  are cut so that the front wall  2 , the first side wall  5  and the second side wall  7 , and the rear wall  3  have different lengths on one end (or both ends) of the bag. As shown in  FIG. 1 , the first side wall  5  and the second side wall  7  are cut to different lengths on either side of the gusset portion  6  and  8 , respectively. As shown in  FIG. 1  the first end  9  of bag  1  has portions  3   a  and  3   b  of the rear wall  3  of the bag that extend further from the body of the bag  1  than do portions  5   a  and  7   a  of the first side wall  5  and second side wall  7 , respectively, which in turn extend further from the body of the bag  1  than do portions  5   b  and  7   b  of the first side wall  5  and second side wall  7 , respectively, which in turn extend further from the body of the bag  1  than does the top end of the front wall  2  of the bag  1 . In addition, the bottom end of the front wall  2  at the second end  10  of bag  1  extends further from the body of the bag  1  than do portions  5   c  and  7   c  of the first side wall  5  and second side wall  7 , respectively, which in turn extend further from the body of the bag  1  than do portions  5   d  and  7   d  of the first side wall  5  and second side wall  7 , respectively, which in turn extend further from the body of the bag  1  than do portions  3   c  and  3   d  the bottom end of the rear wall  3  of the bag  1 . Therefore, in the embodiment shown in  FIG. 1  both of the ends of the bag  1  have a “step cut.” Also shown is weakened portion  20 , which in this embodiment is near the first end  9  of the bag  1  and comprises a plurality of perforations  21  extending from a first end  21   a  on the front wall  2  of the bag  1  across the first side wall  5  of the bag  1  to a second end  21   b  on the rear wall  3  of the bag  1 . The weakened area is generally on or near the fold line (not shown) for closing or sealing the first end  9  of the bag  1 . This weakened portion can be opened with less force than required to open or tear other portions of the bag  1 . 
     Referring to  FIG. 2 , the upper portion of the bag  1  from  FIG. 1  is shown after sealing the first end  9  of the bag  1 . Visible in  FIG. 2  is front wall  2 , back wall  3  having portions  3   a  and  3   b , seam  4 , first side wall  5  having gusset portion  6 , and weakened portion  20  comprising a plurality of perforations  21  terminating at second end  21   b.    
     Bag  1  can be opened as shown in  FIG. 3  through  FIG. 6 .  FIG. 3  once again shows the upper portion of the bag  1  from  FIG. 2 , and visible is front wall  2 , back wall  3  having portions  3   a  and  3   b , seam  4 , first side wall  5  having gusset portion  6 , and weakened portion  20  comprising a plurality of perforations  21  terminating at second end  21   b . Bag  1  is opened by initially pulling on the portions  3 ′ and  3 ″ of the rear wall  3  on both sides of the plurality of perforations  21 , which creates a tear in the weakened portion  20  of the bag  1  and begins separating the portions of the first side wall  5  that are separated by the gusset portion  6 . In  FIG. 4  the portions  3 ′ and  3 ″ of the rear wall  3  on both sides of the plurality of perforations  21  are further pulled apart, resulting in the expansion of the tear in the weakened portion  20  toward the second end  21   b  of the plurality of perforations  21 . Additionally visible in  FIG. 4  are front wall  2 , back wall  3  having portions  3   a  and  3   b , seam  4 , and first side wall  5  having gusset portion  6 . In  FIG. 5  the portions  3 ′ and  3 ″ of the rear wall  3  on both sides of the plurality of perforations  21  are pulled completely apart, resulting in the expansion of the tear in the weakened portion  20  further toward the second end  21   b  of the plurality of perforations  21  and to the first end  21   a  of the plurality of perforations (not visible in  FIG. 5 ). This results in uncovering the top end  6   a  of the gusset portion  6  of the first side wall  5 , which can then be pulled open. Additionally visible in  FIG. 5  are front wall  2 , back wall  3  having portions  3   a  and  3   b , and seam  4 . In  FIG. 6  the plurality of perforations  21  are pulled completely apart, resulting in the expansion of the tear in the weakened portion  20  to the second end  21   b  of the plurality of perforations  21 . This results in a large opening in bag  1  that can be used to pour out the contents of the bag  1 . Additionally visible in  FIG. 6  are front wall  2 , back wall  3  having portions  3   a ,  3   b ,  3 ′ and  3 ″, seam  4 , first side wall  5  and gusset portion  6  having a top end  6   a.    
     Referring to  FIG. 7 , the upper portion of the bag  1  from  FIG. 1  is shown after sealing the first end  9  of the bag  1 , with optional adhesive  30  located near the top end of the first side wall  5 , which serves to keep the top end of the first side wall  5  closed (see arrows). Although not visible in  FIG. 7 , the optional adhesive can also be applied near the top end of the second side wall. Although shown as a spot in  FIG. 7 , the adhesive can be applied in any manner that results in the closure of the top end of the first side wall  5 , for example as a strip that runs from the edge of the intersection of the first side wall  5  and the back wall  3  to the edge of the intersection of the first side wall  5  and the front wall  2 . Also visible in  FIG. 7  is front wall  2 , back wall  3  having portions  3   a  and  3   b , seam  4 , first side wall  5  having gusset portion  6 , and weakened portion  20  comprising a plurality of perforations  21  terminating at second end  21   b.    
     Once the bag  1  is sealed at one end, it can be filled with the desired materials. For example, it has been found that a bag  1  with dimensions of 16.5 inches by 6.5 inches by 39.5 inches can durably hold up to about fifty five (55) pounds of material without showing undue stress, undue tearing, undue breakage, undue deformation, or leakage or the like. It is believed that any bulk material can be contained by bag  1 , and in certain embodiments the contents can weigh up to 100 pounds or so without undue risk of tearing or damage to bag  1 . Once the bag  1  is filled, the second end typically needs to be sealed. The second end of the bag  1  can be sealed in a similar manner as that described above. Alternatively, the bag  1  can have its second end sealed by conventional means such as sewing. Still another approach is to stitch the second end, and then seal the second end in a manner like that described above (not shown). Although not shown, those skilled in the art will understand and appreciate that a second end of bag  1  can be sealed using any conventional technique once bag  1  has been filled with the selected amount of the desired material. 
     Referring to  FIG. 8 , a planar view of an embodiment of a substantially flat sheet of material from which a “step cut” bag  101  is to be formed is shown. Shown on the sheet are front wall  102 , rear wall  103 , seam  104 , first side wall  105  having gusset portion  106 , and second side wall  107  having gusset portion  108 . As shown in  FIG. 8 , the bag  101  has a first or top end  109  and a second or bottom end  110 , and thus each of the front wall  102 , rear wall  103 , first side wall  105  and second side wall  107  has a first or top end and a second or bottom end. It will be apparent, however, that the orientation of the bag ends  109  and  110  are unimportant and the “top” and “bottom” references are useful but may change depending upon the orientation from which one views the bag. Bag  101  is considered a “step cut” bag because the front wall  102 , the first side wall  105  and the second side wall  107 , and the rear wall  103  are cut so that the front wall  102 , the first side wall  105  and the second side wall  107 , and the rear wall  103  have different lengths on one end (or both ends) of the bag. As shown in  FIG. 8 , the first side wall  105  and the second side wall  107  are cut to different lengths on either side of the gusset portion  106  and  108 , respectively. As shown in  FIG. 8  the first end  109  of bag  101  has portions  103   a  and  103   b  of the rear wall  103  of the bag that extend further from the body of the bag  101  than do portions  105   a  and  107   a  of the first side wall  105  and second side wall  107 , respectively, which in turn extend further from the body of the bag  101  than do portions  105   b  and  107   b  of the first side wall  105  and second side wall  107 , respectively, which in turn extend further from the body of the bag  101  than does the top end of the front wall  102  of the bag  101 . In addition, the bottom end of the front wall  102  at the second end  110  of bag  101  extends further from the body of the bag  101  than do portions  105   c  and  107   c  of the first side wall  105  and second side wall  107 , respectively, which in turn extend further from the body of the bag  101  than do portions  105   d  and  107   d  of the first side wall  105  and second side wall  107 , respectively, which in turn extend further from the body of the bag  101  than do portions  103   c  and  103   d  the bottom end of the rear wall  103  of the bag  101 . Therefore, in the embodiment shown in  FIG. 8  both of the ends of the bag  101  have a “step cut.” In addition, the portions  105   a  and  105   b ,  107   a  and  107   b ,  105   c  and  105   d , and  107   c  and  107   d  are not separated by a straight line, but rather an angled cut (see circles). Although in  FIG. 8  this cut is shown as about 45°, the angle can vary in different embodiments (not shown). This angled cut serves to further prevent leakage of contents out of the bag, or infestation of organisms into the contents of the bag. Also shown is weakened portion  120 , which in this embodiment is near the first end  109  of the bag  101  and comprises a plurality of perforations  121  extending from a first end  121   a  on the front wall  102  of the bag  101  across the first side wall  105  of the bag  101  to a second end  121   b  on the rear wall  103  of the bag  101 . The weakened area is generally on or near the fold line (not shown) for closing or sealing the first end  109  of the bag  101 . This weakened portion can be opened with less force than required to open or tear other portions of the bag  101 . 
     Referring to  FIG. 9 , a planar view of an embodiment of a substantially flat sheet of material from which a bag  201  is to be formed is shown. Shown on the sheet are front wall  202 , rear wall  203 , seam  204 , first side wall  205  having gusset portion  206 , and second side wall  207  having gusset portion  208 . As shown in  FIG. 9 , the bag  201  has a first or top end  209  and a second or bottom end  210 , and thus each of the front wall  202 , rear wall  203 , first side wall  205  and second side wall  207  has a first or top end and a second or bottom end. It will be apparent, however, that the orientation of the bag ends  209  and  210  are unimportant and the “top” and “bottom” references are useful but may change depending upon the orientation from which one views the bag. The top end  209  of bag  201  is has a “step cut” because the front wall  202 , the first side wall  205  and the second side wall  207 , and the rear wall  203  are cut so that the front wall  202 , the first side wall  205  and the second side wall  207 , and the rear wall  203  have different lengths. As shown in  FIG. 9 , the first side wall  205  and the second side wall  207  are cut to different lengths on either side of the gusset portion  206  and  208 , respectively. As shown in  FIG. 9  the first end  209  of bag  201  has portions  203   a  and  203   b  of the rear wall  203  of the bag  201  that extend further from the body of the bag  201  than do portions  205   a  and  207   a  of the first side wall  205  and second side wall  207 , respectively, which in turn extend further from the body of the bag  201  than do portions  205   b  and  207   b  of the first side wall  205  and second side wall  207 , respectively, which in turn extend further from the body of the bag  201  than does the top end of the front wall  202  of the bag  201 . In the embodiment shown in  FIG. 9 , the bottom end of the front wall  202 , the first side wall  205 , the second side wall  207 , and the rear wall  203  at the second end  210  of bag  201  each extend the same distance from the body of the bag  201 . Therefore, in the embodiment shown in  FIG. 9  the bottom end  210  of the bag  201  has a “flush cut.” Although not shown, in certain embodiments the top end of the bag can be flush cut, and the bottom end of the bag can be step cut. Also shown is weakened portion  220 , which in this embodiment is near the first end  209  of the bag  201  and comprises a plurality of perforations  221  extending from a first end  221   a  on the front wall  202  of the bag  201  across the first side wall  205  of the bag  201  to a second end  221   b  on the rear wall  203  of the bag  201 . The weakened area is generally on or near the fold line (not shown) for closing or sealing the first end  209  of the bag  201 . This weakened portion can be opened with less force than required to open or tear other portions of the bag  201 . 
     Referring to  FIG. 10 , a planar view of an embodiment of a substantially flat sheet of material from which a flush cut bag  301  is to be formed is shown. Shown on the sheet are front wall  302 , rear wall  303 , seam  304 , first side wall  305  having gusset portion  306 , and second side wall  307  having gusset portion  308 . As shown in  FIG. 10 , the bag  301  has a first or top end  309  and a second or bottom end  310 , and thus each of the front wall  302 , rear wall  303 , first side wall  305  and second side wall  307  has a first or top end and a second or bottom end. It will be apparent, however, that the orientation of the bag ends  309  and  310  are unimportant and the “top” and “bottom” references are useful but may change depending upon the orientation from which one views the bag. The top end  309  of bag  301  has a “flush cut” because the front wall  302 , the first side wall  305  and the second side wall  307 , and the rear wall  303  are cut to the same length. In the embodiment shown in  FIG. 10 , the bottom end of the front wall  302 , the first side wall  305 , the second side wall  307 , and the rear wall  303  at the second end  310  of bag  301  each extend the same distance from the body of the bag  301 . Therefore, in the embodiment shown in  FIG. 10  the bottom end  310  of the bag  301  also has a “flush cut.” Also shown is weakened portion  320 , which in this embodiment is near the first end  309  of the bag  301  and comprises a plurality of perforations  321  extending from a first end  321   a  on the front wall  302  of the bag  301  across the first side wall  305  of the bag  301  to a second end  321   b  on the rear wall  303  of the bag  301 . The weakened area is generally on or near the fold line (not shown) for closing or sealing the first end  309  of the bag  301 . This weakened portion can be opened with less force than required to open or tear other portions of the bag  301 . 
     Referring to  FIG. 11 , a planar view of an embodiment of a substantially flat sheet of material from which a “step cut” bag  401  is to be formed is shown. Shown on the sheet are front wall  402 , rear wall  403 , seam  404 , first side wall  405  having first gusset portion  406 , and second side wall  407  having second gusset portion  408 . As shown in  FIG. 11 , the bag  401  has a first or top end  409  and a second or bottom end  410 , and thus each of the front wall  402 , rear wall  403 , first side wall  405  and second side wall  407  has a first or top end and a second or bottom end. It will be apparent, however, that the orientation of the bag ends  409  and  410  are unimportant and the “top” and “bottom” references are useful but may change depending upon the orientation from which one views the bag. Bag  401  is considered a “step cut” bag because the front wall  402 , the first side wall  405  and the second side wall  407 , and the rear wall  403  are cut so that the front wall  402 , the first side wall  405  and the second side wall  407 , and the rear wall  403  have different lengths on both ends of the bag. As shown in  FIG. 11 , the first side wall  405  and the second side wall  407  are cut to different lengths on either side of the gusset portion  406  and  408 , respectively. As shown in  FIG. 11  the first end  409  of bag  401  has portions  403   a  and  403   b  of the rear wall  403  of the bag that extend further from the body of the bag  401  than do portions  405   a  and  407   a  of the first side wall  405  and second side wall  407 , respectively, which in turn extend further from the body of the bag  401  than do portions  405   b  and  407   b  of the first side wall  405  and second side wall  407 , respectively, which in turn extend further from the body of the bag  401  than does the top end of the front wall  402  of the bag  401 . In addition, the bottom end of the front wall  402  at the second end  410  of bag  401  extends further from the body of the bag  401  than do portions  405   c  and  407   c  of the first side wall  405  and second side wall  407 , respectively, which in turn extend further from the body of the bag  401  than do portions  405   d  and  407   d  of the first side wall  405  and second side wall  407 , respectively, which in turn extend further from the body of the bag  401  than do portions  403   c  and  403   d  the bottom end of the rear wall  403  of the bag  401 . Therefore, in the embodiment shown in  FIG. 11  both of the ends of the bag  401  have a “step cut.” However, the skilled artisan will readily appreciate that in other embodiments (not shown), one or both ends of the bag can be a different type of step cut, or another type of cut altogether, for example a flush cut end as described herein. As shown in  FIG. 11 , the portions  403   a  and  405   a ,  405   b  and  402   a ,  402   a  and  407   b ,  407   a  and  403   b ,  403   c  and  405   d ,  405   c  and  402   c ,  402   c  and  407   c , and  407   d  and  403   d , respectively, are separated from one another not by straight lines and right angles but by curved portions or edges, which in  FIG. 11  are shown as radial (circular) elements. Although one particular size and shape of radial portion is shown in  FIG. 11 , for the features between the foregoing portions, those skilled in the art will appreciate that in other embodiments (not shown), these radial portions can be as small or as large as desired. In addition, the portions  405   a  and  405   b ,  407   a  and  407   b ,  405   c  and  405   d , and  407   c  and  407   d , respectively, are not defined or separated by a radial portion or edge, but rather an angled portion or edge (see circles). Although in  FIG. 11  this angled portion is shown as about 45° with respect to the top end of the front wall, the angle can vary in different embodiments (not shown). These radial and angled portions serve to further prevent breakage, leakage of contents out of the bag, or infestation of organisms into the contents of the bag, by providing extra material at one end of the bag that improves sealing. Further shown in  FIG. 11  is cut-out  411  and corresponding tab  412  at opposing ends of the seam  404 . Since the bag  401  is formed from a continuous sheet of material, the formation of the cut-out  411  (removal of material) at one end of the bag  401  results in a tab  412  (extra material) at the other end of the bag  401 . The cut out  411  and tab  412  extend into the seam  404 , and also serve to further prevent breakage, leakage of contents out of the bag, or infestation of organisms into the contents of the bag. This is because since extra material can be present between the seam  404  of the bag and the edge of the rear panel  403   b  of the bag that is not sealed, a hole can be present that can serve as an access point into or out of the sealed bag. But the presence of the cut-out  411  and the tab  412  ensures that the ends of any such hole will be sealed, preventing access into or out of the sealed bag. The cut-out  411  and tab  412  can be any depth/height desired, and can extend further into the seam as desired (not shown). Although in  FIG. 11  the cut-out  411  and tab  412  are shown as extending from within the seam  404  to the edge of the rear panel  403   b  of the bag, in other embodiments (not shown) the cut-out and tab can extend from within the seam  404  only a portion of the distance to the edge of the rear panel  403   b  of the bag  401 . Furthermore as shown, the tab and cut-out are illustrated as primarily rectangular in shape. It is understood that the shape is not limited to rectangles but can also be configured as an angular or rounded cut-out and matching tab as long as the configuration fits together to form a seal effective to prevent leakage or infestation. Additionally, in other embodiments (not shown), the bag can comprise an easy open or easy access feature, such as the weakened portion near the top of the bag as shown herein above (for example in  FIG. 8 ), or the easy open features detailed in United States Patent Application Publication Number US 2013/0206631 and United States Patent Application Publication Number US 2013/0209002, each of which is incorporated by reference herein in its entirety. 
     Referring to  FIG. 12 , a planar view of the top portion of an embodiment of a substantially flat sheet of material from which a bag  501  is to be formed is shown. Shown on the sheet are front wall  502 , rear wall  503 , seam  504 , first side wall  505  having first gusset portion  506 , and second side wall  507  having second gusset portion  508 . As shown in  FIG. 12 , the bag  501  has a first or top end  509  and a second or bottom end  510  (not visible in  FIG. 12 ), and thus each of the front wall  502 , rear wall  503 , first side wall  505  and second side wall  507  has a first or top end and a second or bottom end. It will be apparent, however, that the orientation of the bag ends  509  and  510  are unimportant and the “top” and “bottom” references are useful but may change depending upon the orientation from which one views the bag. The top end  509  of bag  501  has a “step cut” because the front wall  502 , the first side wall  505  and the second side wall  507 , and the rear wall  503  are cut so that the front wall  502 , the first side wall  505  and the second side wall  507 , and the rear wall  503  have different lengths. As shown in  FIG. 12 , the first side wall  505  and the second side wall  507  are cut to different lengths on either side of the gusset portion  506  and  508 , respectively. As shown in  FIG. 12  the first end  509  of bag  501  has portions  503   a  and  503   b  of the rear wall  503  of the bag  501  that extend further from the body of the bag  501  than do portions  505   a  and  507   a  of the first side wall  505  and second side wall  507 , respectively, which in turn extend further from the body of the bag  501  than do portions  505   b  and  507   b  of the first side wall  505  and second side wall  507 , respectively, which in turn extend further from the body of the bag  501  than does the top end of the front wall  502  of the bag  501 . As shown in  FIG. 12 , the portions  503   a  and  505   a ,  505   a  and  505   b ,  505   b  and  502   a ,  502   a  and  507   b ,  507   b  and  507   a , and  507   a  and  503   b , respectively, are separated not by straight lines and right angles but by curved portions or edges, such as radial (circular) portions as shown. Although one particular size and shape of the curved portions is shown in  FIG. 12 , those skilled in the art will understand that in other embodiments (not shown) these curved edges can be of different shapes (e.g., elliptical, or different segments of a curve, etc.), and can be as small or as large as desired. These curved portions serve to further prevent breakage or leakage of contents out of the bag, or infestation of organisms into the contents of the bag. Further shown in  FIG. 12  is cut-out  511  at one end of the seam  504  (corresponding tab  512  at the other end of the seam  504  is not shown in  FIG. 12 ). Since the bag  501  is formed from a continuous sheet of material, formation of the cut-out  511  (removal of material) at one end of the bag  501  results in a tab (extra material; not shown in  FIG. 12 ) at the other end of the bag  501 . The cut out  511  and tab (not shown in  FIG. 12 ) extend into the seam  504 , and also serve to further prevent breakage, leakage of contents out of the bag, or infestation of organisms into the contents of the bag. The cut-out  511  and tab (not shown) can be any depth/height desired, and can extend further into the seam as desired (not shown). Although in  FIG. 12  the cut-out  511  (and corresponding tab, not shown) is shown as extending from within the seam  504  to the edge of the rear panel  503   b  of the bag, in other embodiments (not shown) the cut-out (and tab) can extend from within the seam  504  only a portion of the distance to the edge of the rear panel  503   b  of the bag. Additionally, in other embodiments (not shown), the bag can comprise an easy open or easy access feature, such as the weakened portion near the top of the bag as shown herein above (for example in  FIG. 8 ), or the easy open features detailed in United States Patent Application Publication Number US 2013/0206631 and United States Patent Application Publication Number US 2013/0209002, each of which is incorporated by reference herein in its entirety. 
     Referring to  FIG. 13A , shown is an outline of a portion of one end of a bag  600  with a step cut end, generally corresponding to a mirror image of the region marked as “A” in  FIG. 11 , detailing an alternate embodiment with angled portions between the front panel  602  of the bag and the first section of the side wall  607 ′, between the first section of the side wall  607 ′ and the second section of the side wall  607 ″, and between the second section of the side wall  607 ″ and the back panel  603  of the bag, respectively, and a feature  613  at one end of the bag that extends into the seam. Since the bag  600  is formed from a continuous sheet of material, the feature  613  forms a cut-out  611  (removal of material; see  FIG. 13B ) at one end of the bag and a tab  612  (extra material; see  FIG. 13C ) at the other end of the bag.  FIG. 13B  shows an image of one end of the bag depicted in  FIG. 13A  upon sealing the seam  604 , showing cut-out  611 .  FIG. 13C  shows an image of the other end of the bag depicted in  FIG. 13A  upon sealing the seam  604 , showing the tab  612 . 
     Referring to  FIG. 14A , shown is an outline of a portion of one end of a bag  700  with a step cut end, generally corresponding to a mirror image of the region marked as “A” in  FIG. 11 , detailing an alternate embodiment with a combination of radial and angled cuts between the front panel  702  of the bag and the first section of the side wall  707 ′, between the first section of the side wall  707 ′ and the second section of the side wall  707 ″, and between the second section of the side wall  707 ″ and the back panel  703  of the bag, respectively, and a feature  713  at one end of the bag  700  that extends into the seam. Since the bag  700  is formed from a continuous sheet of material, the feature  713  forms a cut-out  711  (removal of material; see  FIG. 14B ) at one end of the bag  700  and a tab  712  (extra material; see  FIG. 14C ) at the other end of the bag  700 .  FIG. 14B  shows an image of one end of the bag depicted in  FIG. 14A  upon sealing the seam  704 , showing cut-out  711 .  FIG. 14C  shows an image of the other end of the bag depicted in  FIG. 14A  upon sealing the seam  704 , showing the tab  712 . 
     Those skilled in the art will understand and appreciate that the bag according to the invention may vary in size, dimensions, and shape without departing from the scope of the invention, and that the foregoing description of the preferred embodiments is not intended to limit the scope of the invention as defined by the claims. For example, those skilled in the art will understand and appreciate that the bags shown and described in the various embodiments can have sealed and sewn ends in a tubular bag with side gussets as shown, or a block bottom and top, or a combination thereof, although not shown. Those skilled in the art will also appreciate that a weakened portion or area can be provided in a number of ways that may vary from those expressly described and shown, such as by stressing portions of the bag wall with or without deforming or perforating same, as well as varying the size, number, depth, and/or pattern of perforations and/or deformations in a bag wall. Similarly, those skilled in the art will understand that the bags shown and described in the various embodiments may be provided with a re-usable opening (not shown). Such features are conventional with prior art bags. Similarly, those skilled in the art will appreciate that terms such as “front” and “rear,” and “top” and “bottom,” are useful in describing a bag, but essentially depend on a bag&#39;s orientation when such terms are used, and are therefore not limiting as to a bag&#39;s orientation.