Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1998-12-10
2003-06-17
Pyon, Harold (Department: 1772)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C428S034600, C428S035200, C428S500000, C428S515000, C428S516000, C428S517000, C428S518000, C428S520000, C428S522000, C428S523000
Reexamination Certificate
active
06579584
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to film or sheet articles which have been converted into bags, pouches, etc., which a capable of providing a high strength, high abuse package for the packaging of a wide variety of industrial and consumer products. Such packages are subjected to high levels of abuse. The present invention is particularly directed to the use of such packaging for the direct mailing of various products, especially compact disks.
BACKGROUND OF THE INVENTION
There are a wide variety of products which can benefit from being packaged in a high strength flexible film package, i.e., a flexible film package having a high tear resistance, a high burst strength, and/or other desirable characteristics which flow from the use of high strength, highly abuse-resistant packaging materials. High strength packages are resistant to puncture, tearing, failing seals, etc. Moreover such high strength flexible film packaging, due to the relatively small amount of material used in the package, can result in significantly less waste, hence less environmental impact (and easier recycling) than the more bulky alternatives such as wood crates, paper products (e.g., corrugated paper products), foams, etc. which are the most common forms of packaging where a high strength, abuse-resistant package is desired. The light weight and low bulk of such high strength flexible film packaging material also provides significant transport advantages over the more bulky packaging materials above, requiring less energy, to transport due to lighter weight, hence lower postage rates. Such packaging is also more tamper-evident and tamper-resistant than other forms of packaging, such as paper packaging. Moreover, high strength flexible film packaging products which are not reinforced with non-thermoplastic materials are more easily recycled than reinforced products, e.g., more easily than fiberglass reinforced plastic film packaging materials.
One high strength flexible film packaging material which has been in use for some time is marketed by Van Leer Flexibles, Inc. of Houston, Tex. i.e., VALERON® strength film. VALERON® strength film is made from high density oriented and cross-laminated polyethylene, and is stated as being puncture-resistant, tear-resistant, and chemical-resistant. VALERON® strength film is described as being strong, with a smooth surface. balanced tear-resistance, of uniform thickness, is printable with solvent-based and water-based inks, and is laminatable to paper, film, and other substrates. VALERON® strength film is also described as maintaining its properties in harsh environments and as having a temperature operating range of from −70° F. to over 200° F., and as being useful in the flexible packaging, shipping, construction, agricultural, photographic, and tag & label industries. VALERON® strength film is described as having much better tear resistance than single-ply film of the same overall thickness and of the same polymer which has been biaxially oriented. VALERON® strength film has also been stated to provide improvements over even other cross-laminated films because it is annealed, i.e., subjected to an elevated temperature (i.e., from 35° C. to below the lowest melting point of the thermoplastic material present, excluding any adhesive or bonding layer). The annealing process reportedly provides VALERON® strength film with a higher impact strength relative to corresponding unannealed films.
However, VALERON® strength film is an expensive product relative to other films. This expense is undoubtedly due to the costs associated with both the cross-lamination and the annealing. It would be desirable to provide high strength flexible film packaging which has performance characteristics comparable to VALERON® strength film, but which is less complex to manufacture.
SUMMARY OF THE INVENTION
The present invention is directed to a high strength flexible film package which has characteristics comparable to packages formed from the cross-laminated films discussed above, but which is substantially less complex to produce. It has surprisingly been discovered that a non-crosslaminated film having a thickness of from 1 to 2.9 mils provides a package which is highly resistant to impact and burst, i.e., has a parallel plate burst strength of at least 190 inches of water. This high burst strength is unexpected in view of the film's thin gauge, as well as it not being a cross-laminate, and even not necessarily being annealed. This thin, high strength film is simple and relatively inexpensive to produce, while providing a burst strength comparable to more complex and expensive cross-laminated, annealed packaging materials. Moreover, it has been further unexpectedly discovered that the package according to the present invention can utilize polyethylene copolymers, and hence substantially match the chemical-resistance, operating temperature range, and printability associated with cross-laminated, annealed flexible films.
As a first aspect, the present invention is directed to an article comprising a non-crosslaminated film which comprises at least one member selected from the group consisting of linear low density polyethylene, high density polyethylene, homogeneous ethylene/alpha-olefin copolymer, polycarbonate, polyester homopolymer, polyamide, ethylene/acid copolymer, ethylene/ester copolymer, ethylene/vinyl acetate copolymer, ionomer, ethylene/carbon monoxide, very low density polyethylene, low density polyethylene, polyolefin, ethylene/propylene copolymer, ethylene
orbornene copolymer, polystyrene, and ethylene/styrene copolymer. The non-crosslaminated film is bonded to itself or a second component which in turn comprises at least one member selected from the group consisting of linear low density polyethylene, high density polyethylene, homogeneous ethylene/alpha-olefin copolymer, polycarbonate, polyester, polyamide, ethylene/acid copolymer, ethylene/ester copolymer, ethylene/vinyl acetate copolymer, ionomer, ethylene/carbon monoxide, very low density polyethylene, low density polyethylene, polyolefin, ethylene/propylene copolymer, ethylene/propylene/diene terpolymer, ethylene
orbornene copolymer, polystyrene, and ethylene/styrene copolymer. The article has a parallel plate burst strength of at least 190 inches of water and a thickness of from about 1 mil to about 2.9 mils.
Preferably, the non-crosslaminated film is bonded to itself. Preferably, the film has a total thickness of from about 1.2 to 2.9 mils; more preferably, from about 1.2 to 2.8 mils. Preferably, the article has a parallel plate burst strength of from about 190 to 500 inches of water. The second component can be another film or any other object to which the non-crosslaminated film can be heat sealed or otherwise bonded or adhered. Although the film can be a monolayer film or a multilayer film, preferably the film is a multilayer film. Preferably, the film is a multilayer film comprising: (A) a first inner layer and a second inner layer, wherein each of the inner layers comprises at least one member selected from the group consisting of ethylene/vinyl ester copolymer, ethylene/vinyl acid copolymer, ionomer, and homogeneous ethylene/alpha-olefin copolymer having a density of from about 0.87 to 0.91 g/cc; and (B) a first outer layer and a second outer layer, wherein each of the outer layers comprises (a) at least one member selected from the group consisting of linear low density polyethylene, high density polyethylene, low density polyethylene, very low density polyethylene, homogeneous ethylene/alpha-olefin copolymer, olefin homopolymer, polycarbonate, polyamide, ethylene/acid copolymer, ethylene/ester copolymer, ester homopolymer, ionomer, ethylene/carbon monoxide copolymer, ethylene/propylene/diene terpolymer, ethylene
orbornene copolymer, and ethylene/styrene copolymer, as well as (b) at least one member selected from the group consisting of ethylene/vinyl ester copolymer, ethylene/vinyl acid copolymer, ionomer, and homogeneous ethylene/alpha-olefin copolymer having a density of from ab
Cryovac Inc.
Hon Sow-Fun
Hurley Jr. Rupert B.
Pyon Harold
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