Food or edible material: processes – compositions – and products – Packaged or wrapped product
Reexamination Certificate
1999-03-16
2001-04-10
Hendricks, Keith (Department: 1761)
Food or edible material: processes, compositions, and products
Packaged or wrapped product
C426S118000, C426S805000, C383S100000
Reexamination Certificate
active
06214392
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an article comprising a multilayer film suitable for packaging end use, especially a multilayer film suitable for use in the packaging of relatively hard, granular bulk products, such as dry pet food. The article comprises a heat seal of the film to itself or another film, preferably, in the form of a gusseted bag. The present invention also relates to packaged products in which the package comprises the article of the invention.
BACKGROUND OF THE INVENTION
In the packaging of granular bulk products, such as dry pet food, it has been found that if such products are packaged in a sealed plastic bag, the bags, when stacked on a pallet, tend to either burst or topple over. The air inside the package causes the bag to appear to be inflated, i.e., “balloon,” as it is placed under increasing pressure. The ballooning is the result of pressurization within the bag, as the bag is flattened to a point at which the atmosphere sealed therewithin is placed under pressure. The result is that the pressure within the bags causes bags to burst, or causes the stack to topple, or both.
Typically, the bags contain relatively large amounts of packaged product, e.g., from 5 to 20 or more kilograms of granular product. It would be desirable to provide a means for packaging bulk granular product in plastic bags, with the packaged product being stackable without causing the bags to burst or topple over.
SUMMARY OF THE INVENTION
It has been discovered that the packaging of stackable, palletizable bulk product in plastic bags can be carried out if the plastic bag is provided with a vent. The vent allows air to pass out of the plastic bag as the pressure increases from stacking. As a result, the bag is not pressurized, and does not tend to burst or topple. Moreover, if the vent also allows air to enter the bag, the appearance of the bags will remain uniform even though the bags have been subjected to varying pressure during storage and shipment, as a function of the position of the bag in a stack of bags. Allowing air to return into the bag provides the bags with a uniform appearance when displayed for sale.
However, there is the possibility that the vent will allow the bulk product to escape from the bag, as well as the possibility that foreign objects can enter the package through the vent. The escape of bulk product, and the entry of foreign objects, is reduced by providing the bag with a pair of seals each of which has a vent therein, with the vents being offset from one another. The offset vents result in a tortuous path into and out of the plastic bag. As a result, the escape of the bulk product, and the entry of foreign objects, is reduced or eliminated.
As a first aspect, the present invention is directed to a packaged product comprising a packaging article comprising a non-perforated flexible packaging film and a product surrounded by the packaging article. The packaging article comprises a first seal paired with a second seal, with both the first and second seals being of the film to at least one member selected from the group consisting of itself and another film. A discontinuity (i.e., gap) in the first seal provides a first vent, and a discontinuity in the second seal provides a second vent. The first vent is offset from the second vent.
Preferably, the first seal is a heat seal and the second seal is a heat seal.
Preferably, the first vent has a length of from about ⅛ inch to 3 inches, and the second vent has a length of from about ⅛ inch to 3 inches; more preferably from about ¼ to about 2 inches; still more preferably, from about ½ inch to about 1½ inches.
Preferably, the first vent is offset from the second vent by a distance of at least about 1 inch; more preferably, from about 1 inch to about 50 inches; more preferably, from about 1 inch to about 30 inches; more preferably, from about 1 inch to about 20 inches; more preferably, from about 1 inch to about 15 inches; more preferably, from about 3 inches to about 15 inches; more preferably, from about 5 inches to about 15 inches. As used herein, the term “offset” is a distance determined measuring from the inside end of one vent to the inside end of the other vent. Offset vents do not overlap one another, to provide a tortuous path into and out of the package.
Preferably, paired seals are separated by a distance of from about ½ inch to about 4 inches; more preferably, from about ¾ inch to about 2 inches; more preferably, from about 1 inch to 1½ inches. Preferably, the paired seals are linear and parallel to one another. Alternatively, they can be curved seals, which also are preferably parallel to one another.
Preferably, the product has a weight of at least about 5 kilograms; more preferably, at least about 10 kilograms; more preferably, at least about 12 kilograms; more preferably, at least about 16 kilograms; more preferably, at least about 20 kilograms. Preferably, the product has a weight of no more than about 50 kilograms.
Preferably, the product comprises granular, dry edible particulates. Preferably, the granular, dry edible particulates comprise at least one member selected from the group consisting of livestock feed, sugar, coffee, cookies, cereal, cake mix, crackers, chips, powdered milk, charcoal, cement, fertilizer, lime, pesticide, herbicide, and plant food. More preferably, the product comprise granular, dry pet food.
Preferably, the packaging article is a member selected from the group consisting of an end-seal bag and a side-seal bag. In one preferred embodiment, the packaging article comprises side gussets, and preferably further comprises a longitudinal lap seal. In another preferred embodiment, the packaging article comprises a bottom gusset, and preferably further comprises a first side seal and a second side seal.
Preferably, the first seal is a seal of the film to itself, and the second seal is a seal of the film to itself. Preferably, the first seal is a seal of an inside layer of the film to itself, and the second seal is a seal of the inside layer of the film to itself.
Preferably, packaging article comprises a multilayer film having: (A) a first film layer which is an inside film layer comprising at least one member selected from the group consisting of ethylene/alpha-olefin copolymer and polystyrene; (B) a second film layer comprising at least one member selected from the group consisting of ethylene/unsaturated ester copolymer, anhydride-modified ethylene/alpha-olefin copolymer, anhydride-modified ethylene/ester copolymer, acid-modified ethylene/alpha-olefin copolymer, acid-modified ethylene/acid copolymer, and polystyrene; (C) a third film layer comprising at least one member selected from the group consisting of ethylene/alpha-olefin copolymer and polystyrene; (D) a fourth film layer which comprises at least one member selected from the group consisting of ethylene homopolymer, ethylene/alpha-olefin copolymer, ethylene/vinyl alcohol copolymer, polyvinylidene chloride, polyamide, polyester, polyalkylene carbonate, polyacrylonitrile, and ethylene/unsaturated ester copolymer.
Preferably, at least 85 percent of the film, based on total film volume, consists of at least on member selected from the group consisting of polyolefin homopolymer, polyolefin copolymer, ethylene/ester copolymer, polystyrene, styrene/butadiene copolymer, EVOH, PVDC, and polyacrylonitirile (more preferably, from about 87 to about 100; still more preferably from about 89 to about 100; yet still more preferably, from about 90 to about 100; even yet still more preferably, from about 92 to about 100; and even still more preferably, from about 95 to about 100 volume percent).
Preferably, the film has a total thickness of at least 2 mils, and an impact strength of at least about 1.5 ft-lbs (preferably, at least 1.6 ft-lbs; more preferably, at least 1.7 ft-lbs). Preferably, the film has an impact strength of from about 1.5 to about 20 ft-lb; more preferably, from about 2 to about 5 ft-lb. Preferably, the film has a ball burst impact st
Cryovac Inc.
Dauerman Sherry A.
Hendricks Keith
Hurley Jr. Rupert B.
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