US-12617585-B2 - Recyclable woven plastic bags with quad-seal and/or K-seal

US12617585B2US 12617585 B2US12617585 B2US 12617585B2US-12617585-B2

Abstract

A recyclable 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 a woven polyethylene, polypropylene, or combination thereof layer which can be laminated using polyethylene, polypropylene, or combination thereof resin with a film layer formed from polyethylene, polypropylene, or combination thereof, can form a sealed corner bag and/or a diagonal sealed bag, and can have one or more 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.

Inventors

Jacobo Bazbaz
Alberto Zaroli
Vladimir Marin
Brian Walther
Markus Kronigsfeld

Assignees

POLYTEX FIBERS LLC

Dates

Publication Date: 20260505
Application Date: 20240816

Claims (20)

1 . A bag comprising: a front wall, a back wall, a first side wall, and a second side wall, each having a top end and a bottom end; wherein the first side wall and the second side wall are disposed on opposite sides of the bag and connect the front wall to the back wall; wherein each of a first edge of the front wall and a first edge of the first side wall, a first edge of the back wall and a second edge of the first side wall, a second edge of the back wall and a second edge of the second side wall, and a second edge of the front wall and a first edge of the second side wall is heat sealed to form a bag corner and thereby form a folded tube; wherein each of the front wall, back wall, first side wall and second side wall comprise (i) a first layer comprising woven strips comprising a first material that comprises polyethylene, polypropylene, or a combination thereof and (ii) a second layer laminated to the first layer, said second layer comprising a second material that comprises a polyethylene film, a polypropylene film, or a combination thereof, wherein the first material and the second material comprise the same material and the bag is recyclable; and wherein each of the bag corners exhibit less than a 3% failure rate when the bag is subjected to a drop test in accordance with ASTM D5276.
2 . The bag of claim 1 , wherein the second layer is laminated to the first layer by a film layer comprising a third material that comprises polyethylene, polypropylene, or a combination thereof, and wherein the first material, the second material, and the third material comprise the same material.
3 . The bag of claim 1 , wherein the second layer forms an exterior surface of the bag.
4 . The bag of claim 1 , wherein the front wall, the back wall, the first side wall, and the second side wall further comprise a third layer comprising a polyethylene laminate resin, a polypropylene laminate resin, or a combination thereof, and the third layer forms an interior surface of the bag.
5 . The bag of claim 4 , wherein the front wall, the back wall, the first side wall, and the second side wall further comprise a fourth layer comprising a polyethylene film, a polypropylene film, or a combination thereof and a fifth layer comprising a polyethylene laminate resin, a polypropylene laminate resin, or a combination thereof, wherein the fifth layer laminates the fourth layer to the first layer.
6 . The bag of claim 1 , wherein the bag comprises no more than approximately 20% of other material, the other material being different from the first material and the second material.
7 . The bag of claim 1 , wherein the first layer forms an interior surface of the bag.
8 . The bag of claim 1 , wherein the first layer further comprises a high-density polyethylene fabric, a high-density polypropylene fabric, or a combination thereof.
9 . The bag of claim 8 , wherein the second layer further comprises a low-density polyethylene fabric, a low-density polypropylene fabric, or a combination thereof.
10 . The bag of claim 1 , wherein the first layer further comprises a low-density polyethylene fabric, a low-density polypropylene fabric, or a combination thereof.
11 . The bag of claim 10 , wherein the second layer further comprises a high-density polyethylene fabric, a high-density polypropylene fabric, or a combination thereof.
12 . The bag of claim 1 , wherein at least one of the top end or the bottom end is heat sealed to close the bag.
13 . The bag of claim 1 , wherein a portion of the top end of the front wall is folded over the top end of the bag and an interior surface portion of the front wall is sealed to a portion of an exterior surface portion of the back wall proximal the top end of the back wall, to form a sealed closure of the top end of the bag, wherein at least a portion of a surface of the front wall is adapted to be separable from a portion of the back wall by applying a peel strength and wherein the peel strength is associated with a plurality of surface treatments applied to at least the interior surface portion of the front wall or the exterior surface portion of the back wall.
14 . The bag of claim 13 , wherein the peel strength is lower when the front wall or the back wall is pulled in a first direction than when the front wall or the back wall is pulled in a second direction different from the first direction.
15 . The bag of claim 1 , wherein the top end and the bottom end are sealed, and wherein the bag comprises between 10 and 60 pounds by weight of a filling material.
16 . The bag of claim 1 , wherein each of the bag corners exhibit less than a 3% failure rate when the bag is subjected to a drop test in accordance with ASTM D5276 including hanging a filled bag at 145° F. for 72 hours followed by a 6 point drop test from a height of at least 4 feet, followed by storage at −27° F. for 24 hours followed by another 6 point drop test from a height of at least 4 feet.
17 . The bag of claim 1 , wherein each of the bag corners exhibit less than a 3% failure rate when the bag is subjected to a drop test in accordance with ASTM D5276 including hanging a filled bag at 145° F. for 144 hours followed by a 10 point drop test from a height of at least 4 feet followed by storage at −27° F. for 72 hours followed by another 10 point drop test from at height of at least 4 feet.
18 . The bag of claim 1 , wherein each of the front wall, the back wall, the first side wall, and the second side wall further comprise a third layer comprising a third material that comprises a polyethylene laminate resin, a polypropylene laminate resin, or a combination thereof and a fourth layer comprising a fourth material that comprises a polyethylene film, a polypropylene film, or a combination thereof, wherein the first material, the second material, the third material and the fourth material comprise the same material and the bag is recyclable, and wherein the fourth layer forms an interior surface of the bag, the second layer forms an exterior surface of the bag, and the third layer bonds the first layer and the second layer.
19 . A bag comprising: a front wall, a back wall, a first side wall, and a second side wall, each having a predetermined size and a top end and a bottom end; wherein the first side wall and the second side wall are disposed on opposite sides of the front wall and the back wall and connect the front wall to the back wall; wherein corners between each of the front wall, the first side wall, and the second side wall, and between the back wall, the first side wall, and the second side wall, are heat sealed; wherein the front wall, the back wall, the first side wall, and the second side wall comprise a plurality of seals arranged at the bottom end and extending between approximately 30° and approximately 45° from an edge of each of the front wall, the back wall, the first side wall, and the second side wall to form diagonal seals at the bottom end, each of the plurality of seals being a heat seal; wherein each of the front wall, back wall, first side wall and second side wall comprise (i) a first layer comprising woven strips comprising a first material comprising polyethylene, polypropylene, or a combination thereof, (ii) a second layer laminated to the first layer, said second layer comprising a second material comprising a polyethylene film, a polypropylene film, or a combination thereof, (iii) a third layer comprising a third material comprising a polyethylene laminate resin, polypropylene laminate resin, or a combination thereof, and the third layer forms an interior surface of the bag, (iv) a fourth layer comprising a fourth material comprising a polyethylene film, a polypropylene film, or a combination thereof, and (v) a fifth layer comprising a fifth material comprising a polyethylene laminate resin, a polypropylene laminate resin, or a combination thereof, wherein the fifth layer laminates the fourth layer to the first layer, and wherein the first material, the second material, the third material, the fourth material, and the fifth material comprise the same material; and wherein the diagonal seals exhibit less than a 3% failure rate when the bag is subjected to a drop test in accordance with ASTM D5276.
20 . The bag of claim 19 , wherein the second layer is laminated to the first layer by a film layer comprising polyethylene, polypropylene, or a combination thereof.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS This application claims the benefit of priority of and is a continuation of U.S. patent Ser. No. 17/367,072 filed Jul. 2, 2021, and entitled RECYCLABLE WOVEN PLASTIC BAGS WITH QUAD-SEAL AND/OR K-SEAL, the entire disclosure of which is hereby incorporated by reference in its entirety for all purposes. FIELD OF THE INVENTION The present disclosure generally relates to recyclable woven plastic bags, and more particularly to recyclable woven plastic bags formed with a quad-seal and/or K-seal. BACKGROUND 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 '979 patent”), issued on Feb. 15, 1983. The '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 '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 '979 patent is hereby incorporated by reference herein. The '979 patent purports to be an improvement for sealing a plastic bag. As noted in the '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 '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 '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 '051 patent”), issued on Oct. 5, 2004, a process for sealing side fold sacks made of plastic film is described. According to the '051 patent, a web of plastic tubular film is cut to provide a stagger