Bag comprising machine direction oriented film
A packaging container comprising an outer layer of machine direction oriented polyethylene (1) bonded to an inner layer of polyethylene (2) by a bonding layer such as adhesive (3). The machine direction oriented polyethylene (1) serves to stiffen the package and provide resistance to heat when the inner sealant layers of polyethylene (2) are heat sealed together. The resulting package (4) simplifies recycling due to the substantial polyethylene composition. Further, additions of degradable additive may be combined with the machine direction oriented polyethylene (1) and polyethylene (2) to enhance degradation.
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BACKGROUND1. Field
This invention relates to flexible bags having a polyethylene, machine direction oriented polyethylene wall structure.
2. Prior Art
Flexible packaging has played an increasing role in containing a wide variety of products ranging from liquid and dry chemicals to food products. Due to this wide variety of products, the flexible packaging industry is constantly changing the characteristics of the bag structures to meet the changing needs of the packers and consumers. Desired bag characteristics include optical clarity, rigidity, toughness, heat resistance, and recyclability.
Free standing, or stand-up pouches, offer better retail presentation since the printed front panel of the pouch is directly in front of the consumer when either hanging from a store rack or sitting on a store shelf. Stand-up pouches, like the one disclosed in U.S. Pat. No. 3,738,565 to Ackley (1973) demonstrate the need for free standing bags. Stand-up pouches often rely on a lamination of polyester, nylon, or polypropylene to polyethylene. The polyester, nylon, or polypropylene offer good clarity, rigidity, and heat resistance while the polyethylene offers a sealant layer to seal the bag closed using heat and pressure. The heat resistance on the outer layer is used to resist sticking to the high temperature sealing jaws of the packer machine. A sealant layer of polyethylene, although needed to seal the bag closed, does not have the rigidity desired in many packaging applications to stand up on a display shelf. A polyethylene to non-polyethylene lamination, however, is problematic for recycling due to the incompatible materials found in the bag.
Other modifications to the bag film structure have been made in the past to achieve different bag characteristics. U.S. Pat. No. 5,827,586 to Yamashita (1998) and U.S. Pat. No. 6,306,472 to Buelow (2001) are examples of film modifications that were needed. Neither of these address the rigidity and recyclability concerns of today's stand-up pouches.
Machine Direction Oriented film or MDO is polyethylene having more heat resistance and rigidity than standard polyethylene film. MDO film is sometimes sold as a sealant layer to packaging facilities to laminate to more rigid plastic films such as the previously mentioned polyester or polypropylene. By laminating MDO film to polyethylene, the entire package can be made of compatible plastics for recycling and still have the desired rigidity and heat resistance of other commonly used laminations.
The preferred embodiment of this invention uses MDO film on the outer wall and a standard polyethylene film on the inside wall of the flexible package.
1 Machine direction oriented polyethylene layer
2 Polyethylene sealant layer
3 Adhesive layer
4 Stand-up pouch
DETAILED DESCRIPTIONThe laminated film of the preferred embodiment of the present invention is shown in
The resulting package simplifies recycling due to the substantial polyethylene (2) and machine direction oriented polyethylene (1) composition. Further, additions of degradable additive may be combined with the machine direction oriented polyethylene (1) and polyethylene (2) to enhance degradation.
Claims
1. A flexible packaging container comprising:
- a. an outer layer of substantially machine direction oriented polyethylene,
- b. a middle bonding layer of material found in the category containing adhesive,
- c. an inner layer of polyethylene,
- whereby said outer layer of said machine direction oriented polyethylene stiffens said flexible packaging container and said inner layer of polyethylene facilitates heat sealing to a corresponding inner layer of polyethylene of said flexible packaging container side wall.
Type: Application
Filed: Jul 21, 2011
Publication Date: Feb 9, 2012
Inventor: Brian E. Votaw
Application Number: 13/136,036
International Classification: B65D 30/08 (20060101);