Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
2002-06-05
2004-11-09
Pyon, Harold (Department: 1772)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S354000, C428S035700, C428S516000, C428S522000, C220S062220, C206S557000
Reexamination Certificate
active
06815057
ABSTRACT:
This invention relates to thermoplastic polymeric films useful in the packaging of food products, especially, cheese and other dairy products. More specifically, the invention is in the field of polymeric thermoplastic films that are thermoformable i.e., may be softened through the application of heat, distorted to a desired shape, and cooled.
Polymeric films are useful in the packaging field for the packaging of products, especially food products. Films used for the packaging of food, generally contain multiple layers in which each layer adds certain desired physical or chemical properties to the completed film. Food packaging methods utilizing polymeric films can be exemplified in many ways, i.e., enveloping the product in a polymeric clear film or placing the product in a rigid structure which is formed from a polymeric thermoplastic film. It is the latter of these methods to which this invention is directed.
The use of thermoformable film structures to form rigid structures such as trays or tubs is known. It is also known that these rigid structures usually require a lidding component. The lidding component can be a flexible sheet material which is adhered to the structure to form a closing and sealing lid. The lidding component can also be a rigid plastic cap. The lidding component can also be a combination of the two.
The use of formed, rigid structures and lidding, in general, is known and applicable to the packaging of food products. For examples, jellies, jams, dressing, yogurt and pudding are commonly packaged in individual servings in formed trays with peelable sheet materials used for lids sealed to the trays. Larger trays and accompanying lids have been used in the packaging of complete servings of prepared foods. However, in the packaging of some food products such as a processed cheese loaf, the packaging is limited to a corrugated box in which the cheese loaf is placed. This type of packaging has the following disadvantages (a) lack of portion control, i.e., smaller individual servings; (b) lack of reclosability; and (c) lack of resealability.
Therefore, there is a need to develop a package for this type of product that will overcome the disadvantages of the old package and yet meet the processing and packaging requirements of the product.
The package for the cheese product must withstand relatively severe processing conditions either at the points where the package is being filled or sealed or at the point where the package and/or its contents is to be used. Such packaging typically encounters substantial heat at the point where the package is filled and sealed, and may be subjected to significant heat at the point where the package is used. At the point of packaging, the packaging may be subjected to, for example, hot-filled product at approximately 165° F. The package must also provide protection to the contained food from the permeation of substances into the package from the outside environment. Substances which can have undesirable affects on the contained product are, for example, oxygen, moisture, contaminants and light. It is especially important to protect the packaged contents from oxygen, moisture and light, in addition to the typical containing and protecting functions of the package. The rigid package also serves as a cheese mold to shape the final product when cooled. The package also needs cheese release or the ability to allow easy removal of the cheese loaf by the consumer without significant residue and adhesion of the product to the container walls.
Resins for providing these individually desired protective properties are known and are available, and are commonly used in packaging applications. For example, oxygen penetration can be successfully impeded through the use of vinyl alcohol polymers such as ethylene vinyl alcohol copolymer and vinylidene chloride copolymers. Moisture penetration may be prevented by use of certain polymers, for example, polyolefins.
Description of the Prior Art
Ramesh, et al., U.S. Pat. No. 5,763,095 discloses a multilayer film having a combination of relatively low oxygen transmission and relatively high carbon dioxide transmission. The film includes at least one layer containing a nylon copolymer.
van der Ploeg, et al., U.S. Pat. No. 4,472,339 discloses a process of manufacturing a plastic cheese mold, comprising: providing a mold having a cavity defined in it, which cavity is shaped to define the exterior wall of the container, and which mold is further comprised of a mandrel, or the like, fitted into the cavity, wherein the mold defines an outer, inwardly facing wall of the cavity and the mandrel, or the like, defines an opposite, inner, outwardly facing wall, and the mold and the mandrel, or the like, being shaped to define a relatively thin walled opening between the outer and opposite inner walls thereof; applying a porous non-woven layer of polyolefin fibers to the inner wall of the mold; and filling the cavity by injection molding with a liquid mass of polyolefin material at an elevated temperature selected for the polyolefin material to heat seal to the fibers of the non-woven layer.
Lulham, et al., U.S. Pat. No. 5,595,623 discloses a method of making a film comprising: blending from about 5% to about 95% by weight of ethylene vinyl acetate copolymer having from about 3% to about 18% by weight of vinyl acetate with from about 5% to about 95% by weight of ethylene/alpha-olefin copolymer having a density of less than about 0.915 g/cc; extruding said blend through a circular coextrusion die; immediately blowing the extrudate to a diameter appropriate for achieving the desired thickness for the final film; cooling the coextruded film; and collapsing the cooled film.
Temple, U.S. Pat. No. 4,977,931 discloses a packing material, generally in sheet form, made from a combination of a support sheet and a water-retentive material that is intimately connected to the support sheet. Moisture or exudate originating from a product enclosed by the packing material is absorbed and retained by the water-retentive material without affecting the physical strength of the support sheet or the packaged product. In a preferred embodiment, the support sheet is made of paper or a polymeric material, such as polyethylene, and the water retentive material is formed from polyacrylonitrile, or a polyacrylonitrile based co-polymer, treated with an alkaline aqueous solution of aliphatic or cycloaliphatic monofunctional or polyfunctional alcohols that have melting points greater than or equal to 110° C. The packaging material is ideal for the packaging of moisture sensitive foods, such as cheese.
It is an object of this invention to provide novel thermoplastic film structures, sheet materials and novel packages made from said thermoplastic film structures and said sheet materials.
The rigid structures which are molded from the thermoplastic film structures of the present invention are capable of withstanding hot-fill temperatures of about 165° F. The rigid structures are also capable of protecting the package contents from penetration, moisture and light and in certain preferred embodiments from oxygen.
It is a specific object of the invention to provide a laminated multiple layer thermoplastic film structure comprising a three layer coextruded portion which is laminated to a coextruded sealant film structure containing a cheese release additive.
It is another specific object of the invention to provide a novel film structure having an oxygen barrier resin core layer in the sealant film structure.
It is another specific object of the invention to provide a rigid structure which is produced from the thermoplastic film structures of the present invention wherein said structure is capable of withstanding a hot-fill temperature of about 165° F.
It is another specific object of the present invention to provide a package comprising a rigid structure which is made from the film structures of the present invention and a lidding component.
Definition of Terms
Unless specifically set forth and defined or otherwise limited, the following terms as
Buelow Duane H.
Douglass Kevin
Hodson Jay D.
McDermott Will & Emery LLP
Miggins Michael C.
Pechiney Emballage Flexible Europe
Pyon Harold
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