Patent Application
20140029873
The present patent application claims priority to Application No. PI1003492-7 filed with the Institute Nacional da Propriedade Industrial of Brazil on Sep. 23, 2010. The entirety of Application No. PI1003492-7 is incorporated in this application by this reference.
This present application relates to a multilayer film, specifically a multilayer film comprising a valve and the use of such film in a web and in a package. The film may be used to package products, including but not limited to powdered products, granulated products or similar products. The valve may be used to eliminate and discharge gases from inside such package.
The use of a multilayer film to form a package is known. A multilayer film comprises various layers. Each layer may have a specific function, such as a barrier layer, a printed layer or otherwise. In a web, the multilayer film may comprise a central area printed with a succession of repeating units for one wall of a package and longitudinal side areas printed with a succession of repeating units for the opposing wall of a package. The film may be formed into a package by various methods known to a person of ordinary skill in the art. Non-limiting examples of such methods include the use of a vertical form-fill-seal (VFFS) machine and the use of a horizontal form-fill-seal (HFFS) machine. On a VFFS machine, the film is folded or otherwise manipulated and longitudinally sealed to form a tube member. The tube member is then sealed across an end, transversally cut, filled with product, sealed across the opposite end and transversally cut. This series of steps is repeated until the web is transformed into individual packages. With each end seal and transversal cut, the transversal cut may separate the end seal into two seals, so that one end seal closes the mouth (or one end) of one package, the transversal cut separates the package from another subsequent package, and the other end seal closes the base (or other end) of the subsequent package. Each package may be substantially in pillow form. The package may be used for various product lines, including food and non-food powdered products, granulated products or similar products.
As a result of the packaging procedure, the film used to form the package and/or the products packaged, gas may be trapped or formed inside the package causing the package to bloat. Such bloated packages may result in problems in handling packages, storing packages, displaying packages, using packages or otherwise.
A non-limiting example of one product line is coffee powder. The multilayer film used for packages for such product line may comprise a barrier layer of, for example, metalized film, to preserve product quality, including but not limited to aroma. However, as a result of the packaging procedure, the barrier layer and/or the particular characteristics of coffee, gases form and cause the problems described above. To address these problems, numerous micro holes have been included in multilayer films used to form packages for coffee. However, such holes allow coffee particles to escape from the package, providing the consumer with the undesirable impression of a leaky package. Furthermore, such holes allow the external atmosphere to enter the package, compromising product quality.
What is needed is a multilayer film which may be used to form packages, where the multilayer film provides a route for gases to escape the package but prevents product from escaping and the external atmosphere from entering.
This need is met by a multilayer film comprising a valve. The multilayer film comprises an exterior layer and an interior layer. Each of the exterior layer and the interior layer may comprise various materials and various layers comprising various materials. The interior layer comprises at least one aperture extending through the interior layer. At various portions of the multilayer film, the exterior layer and the interior layer are bonded. At various other portions of the multilayer film, the exterior layer and the interior layer are not bonded. The non-bonded portion of the multilayer film comprises at least one channel and at least one passage.
The valve comprises the at least one aperture through the interior layer, the at least one channel between the exterior layer and the interior layer, and the at least one passage between the exterior layer and the interior layer; and the valve provides fluid communication from an outer surface of the interior layer to an atmosphere external to the multilayer film. In one embodiment, such fluid communication is provided as follows: The aperture is in fluid communication with a first area of the channel; the second area of the channel intersects the passage at an angle greater than 0 degrees and less than 180 degrees and is in fluid communication with the passage; and the passage extends laterally from a first edge of the multilayer film to an opposing second edge and a first end of the passage and a second end of the passage is each in fluid communication with an atmosphere external to the multilayer film.
In one embodiment, the multilayer film described above may be used to form a web.
In another embodiment, the multilayer film described above may be used to form a package. The package comprises a first seal connecting a first side of the multilayer film to an opposing second side of the multilayer film (or a first edge of the multilayer film to an opposing second edge of the multilayer film) to define a tube member. The package further comprises a second seal through a first wall and a second wall of the tube member such that the second seal extends laterally across the width of both the first wall and the second wall and is near one end of the tube member. A product may then be placed in the tube member sealed with the second seal. A third seal may then be provided through the first wall and the second wall of the tube member such that the third seal extends laterally across the width of both the first wall and the second wall and is near the other end of the tube member. In this embodiment, a valve for the package comprises the at least one aperture through the interior layer, the at least one channel between the exterior layer and the interior layer, and the at least one passage between the exterior layer and the interior layer.
In one embodiment of the package formed from the multilayer film, the first seal comprises a first outlet having a first area and a second area. In this embodiment, a valve for the package comprises the at least one aperture through the interior layer, the at least one channel between the exterior layer and the interior layer, the at least one passage between the exterior layer and the interior layer, and the first outlet, where a first area of the first outlet is in fluid communication with a first end of the passage and a second area of the first outlet is in fluid communication with a second end of the passage.
In another embodiment of the package formed from the multilayer film, the second seal comprises a second outlet and a third seal comprises a third outlet. In this embodiment, a valve for the package comprises the at least one aperture through the interior layer, the at least one channel between the exterior layer and the interior layer, the at least one passage between the exterior layer and the interior layer, the second outlet and the third outlet, where the second outlet is in fluid communication with a second end of the passage and the third outlet is in fluid communication with a first end of the passage.
In a further embodiment of the present application, a method of making the multilayer film described above is described. This method comprises the steps of providing a first layer as the exterior layer, providing a second layer as the interior layer, providing the bonded portion between the interior layer and the exterior layer, providing the non-bonded portion between the interior layer and the exterior layer to form the at least one channel and the at least one passage, and providing the at least one aperture in the interior layer.
In another embodiment of the present application, a method of forming a package comprising the multilayer film described above is described. This method comprises the steps of providing a web of the multilayer film, providing a first seal connecting a first side of the multilayer film to an opposing second side of the multilayer film (or a first edge of the multilayer film to an opposing second edge of the multilayer film) to define a tube member, providing a second seal through a first wall and a second wall of the tube member such that the second seal extends laterally across the width of both the first wall and the second wall and is near one end of the tube member, providing a product in the tube member sealed with the second seal, and providing a third seal through the first wall and the second wall of the tube member such that the third seal extends laterally across the width of both the first wall and the second wall and is near the other end of the tube member. In this embodiment, a valve for the package comprises the at least one aperture through the interior layer, the at least one channel between the exterior layer and the interior layer, and the at least one passage between the exterior layer and the interior layer.
In one embodiment of the method of forming a package from the multilayer film, the method further comprises the step of forming a first area of a first outlet in the first seal and the step of forming a second area of a first outlet in the first seal. In this embodiment, a valve for the package comprises the at least one aperture through the interior layer, the at least one channel between the exterior layer and the interior layer, the at least one passage between the exterior layer and the interior layer, and the first outlet, as the first area of the first outlet is in fluid communication with a first end of the passage and the second area of the first outlet is in fluid communication with a second end of the passage.
In another embodiment of the method of forming a package from the multilayer film, the method further comprises the step of forming a second outlet in the second seal and the step of forming a third outlet in the third seal. In this embodiment, a valve for the package comprises the at least one aperture through the interior layer, the at least one channel between the exterior layer and the interior layer, the at least one passage between the exterior layer and the interior layer, the second outlet and the third outlet, as the second outlet is in fluid communication with a second end of the passage and the third outlet is in fluid communication with a first end of the passage.
The embodiments described in the present application provide a route for gases to escape or to be discharged from a package but also prevent product from escaping and the external atmosphere from entering. When the pressure in the package is higher than the pressure in the external atmosphere, the gas enters the valve through the at least one aperture, flows through the at least one channel and flows through the at least one passage to the external atmosphere. In some embodiments, the gas flows through a first outlet or a second and a third outlet on its way to the passage ends and the external atmosphere. However, at the same time, product that may possibly enter the at least one aperture does not flow through the at least one channel or the at least one passage due to the configuration and position of such elements. Therefore, product does not escape the package to the external atmosphere. Furthermore, gas does not flow from the external atmosphere to the product, as the pressure in the package and the pressure in the external atmosphere tend to equalize after gas in the package is discharged to the external atmosphere (as described above). Additionally, the weight of the package and the configuration and position of the at least one passage, the at least one channel and the at least one aperture make such ingress difficult. As such, the valve may operate as a non-return/one-way/check/gas-discharge valve to allow gas egress to the external atmosphere but to prevent gas ingress from the external atmosphere.
As used throughout this application, the term “film” refers to a plastic web of any thickness and is not limited to a plastic web having a thickness of less than about 10 mil. The term “sheet” refers to a plastic web of any thickness and is not limited to a plastic web having a thickness of greater than about 10 mil.
As used throughout this application, the term “web” refers to a continuous film or a continuous sheet.
As used throughout this application, the term “package” refers to any device used to wholly or partially surround an item. A package may take many, various forms. For example, the term “package” may include bags that wholly surround an item (or items) to be packaged; the term “package” may also include films that partially surround an item (or items) to be packaged and, when used in conjunction with another material (such as a tray), wholly surround an item (or items).
As used throughout this application, the term “about” refers to approximately, rounded up or down to, reasonably close to, in the vicinity of, or the like. The term “approximate” is synonymous with the term “about.”
As used throughout this application, the term “adjacent” refers to being near or close in proximity. It includes but is not limited to being reasonably close to or in the vicinity of as well as touching, having a common boundary or having direct contact.
As used throughout this application, the term “exterior layer” refers to a layer comprising the outermost surface of a film, sheet, web, package or other article. The term “interior layer” refers to a layer comprising the innermost surface of a film, sheet, web, package or other article. Additionally, the exterior layer and the interior layer each have an inner surface and an outer surface. The term “inner surface” refers to a surface touching another layer, and the term “outer surface” refers to a surface not touching another layer.
As used throughout this application, the term “intermediate layer” refers to a layer that is positioned between two other layers. An intermediate layer has two inner surfaces.
As used throughout this application, the term “multilayer” refers to a plurality of layers in a single structure generally in the form of a film, sheet or web which may be made from a polymeric material or a non-polymeric material bonded together by any conventional means known in the art (i.e., coextrusion, lamination, coating or a combination of such). The multilayer film described in the present application comprises a film including as many layers as desired and, preferably, at least two layers.
As used throughout this application, the term “exterior multilayer film” refers to a multilayer film comprising the outermost surface of a film, sheet, web, package or other article. The term “interior multilayer film” refers to a multilayer film comprising the innermost surface of a film, sheet, web, package or other article.
As used throughout this application, the term “coextruded” refers to the process of extruding two or more polymer materials through a single die with two or more orifices arranged so that the extrudates merge and weld together into a laminar structure before chilling (i.e., quenching).
Coextrusion methods known to a person of ordinary skill in the art include but are not limited to blown film coextrusion, slot cast coextrusion and extrusion coating. The flat die or slot cast process includes extruding polymer streams through a flat or slot die onto a chilled roll and subsequently winding the film onto a core to form a roll of film for further processing.
As used throughout this application, the term “blown film” refers to a film produced by the blown coextrusion process. In the blown coextrusion process, streams of melt-plastrfied polymers are forced through an annular die having a central mandrel to form a tubular extrudate. The tubular extrudate may be expanded to a desired wall thickness by a volume of fluid (e.g., air or other gas) entering the hollow interior of the extrudate via the mandrel, and then rapidly cooled or quenched by any of various methods known to those of skill in the art.
As used throughout this application, the term “in fluid communication” refers to free movement of fluid (e.g. air or other gas) from one place to another through an open pathway for fluid. When specified parts are “in fluid communication,” fluid flowing past one specified part also flows past the other specified part with the specified parts being connected by fluid flow and/or the specified parts communicating through fluid flow
As used throughout this application, terms such as “preferably” and “typically” are not used to limit the scope or to imply that certain features are critical, essential or even important to the structure of function. Rather, these (and similar) terms are merely intended to highlight alternative or additional features that may or may not be used in a particular embodiment.
As used throughout this application, the term “layer” refers to a discrete film or sheet component which is coextensive with the film or sheet and has a substantially uniform composition. In referring to a monolayer film, “film,” “sheet” and “layer” are synonymous.
As used throughout this application, the term “aperture” refers to hole, vent, score, slit, slot, perforation, puncture, orifice, opening, inlet or otherwise. Such aperture may be formed by mechanical means, by optical ablation or by other method known to a person of ordinary skill in the art.
As used throughout this application, the term “optical ablation” refers to a method of localized vaporization or decomposition of polymeric material by means of a controlled laser beam which may be used to form an aperture in a thermoplastic material.
As used throughout this application, the term “polymer” refers to a material which is the product of a polymerization or copolymerization reaction of natural, synthetic or combined natural and synthetic monomers and/or co-monomers and is inclusive of homopolymers, copolymers, terpolymers, etc. In general, the layers of the multilayer film described in the present application may comprise a single polymer, a mixture of a single polymer and non-polymeric material, a combination of two or more polymers blended together, or a mixture of a blend of two or more polymers and non-polymeric material. It will be noted that many polymers may be synthesized by the mutual reaction of complementary monomers. It will also be noted that some polymers are obtained by the chemical modification of other polymers such that the structure of the macromolecules that constitute the resulting polymer may be thought of as having been formed by the homopolymerization of a hypothetical monomer.
As used throughout this application, the term “thermoplastic” refers to a polymer or polymer mixture that softens when exposed to heat and then returns to its original condition when cooled to room temperature. In general, thermoplastic materials may include natural or synthetic polymers. Thermoplastic materials may further include any polymer that is cross-linked by either radiation or chemical reaction during manufacturing or post-manufacturing processes.
As used throughout this application, the term “bonded portion” refers to a portion of a multilayer film, sheet, web, package or other article in which layers are bonded, adhered, joined, attached, affixed, connected or otherwise such that no consequential space, gap, open area or otherwise is formed between the layers. Such bonded portion may be formed via heat and pressure, adhesive or other method known to a person of ordinary skill in the art.
As used throughout this application, the term “non-bonded portion” refers to a portion of a multilayer film, sheet, web, package or other article in which layers are not bonded, adhered, joined attached, affixed, connected, laminated or otherwise such that a consequential space, gap, open area or otherwise is formed between the layers. Such non-bonded portion may be formed via an area void of adhesive, an adhesive skip, a pattern-applied adhesive or other method known to a person of ordinary skill in the art.
As used throughout this application, the term “laterally” refers to traversing from side to side, along the length of, from one point to another or otherwise. It is not limited to the machine direction and/or the transverse direction.
As used throughout this application, the term “sealant layer” refers to a layer or layers of a film, sheet, web, package or otherwise involved in the sealing of the film, sheet, web, package or otherwise to itself, to another layer of the same or another film, web, sheet, package or otherwise, and/or to another article, such as a tray. In general, the sealant layer is an interior layer of any suitable thickness that provides for the sealing of the film, sheet, web, package or otherwise to itself or to another layer. With respect to packages having only fin-type seals, as opposed to lap-type seals, the phrase “sealant layer” generally refers to the interior layer of a film, sheet, web, package or otherwise. The sealant layer may also serve as a food contact layer in the packaging of foods.
As used throughout this application, the term “sealant material” refers to any material suitable for a sealant layer. Sealant material includes but is not limited to heat sealable polymeric material such as a polyolefin (e.g., polyethylene or polypropylene) or blend of such. Such polyolefins include, for example, polyethylenes such as low density polyethylene (LDPE), high density polyethylene (HDPE), ethylene alpha-olefin copolymers (EAO) (also referred to as “copolymers of ethylene and at least one alpha-olefin”) (including, for example, plastomers), very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), polypropylene homopotymers, polypropylene copolymers, polybutylene homopolymers, polybutylene copolymers or homogeneous polyolefin resins, such as those made with constrained geometry catalysts or metallocene single-site catalysts, including, for example, copolymers of ethylene or propylene with at least one C4-8 or higher alpha-olefins (e.g., 1-butene, 1-hexene or 1-octene or combinations of such) with a majority of polymeric units derived from ethylene or propylene. Ethylene vinyl acetate (EVA) copolymers, ethylene butyl acrylate copolymers (EBA), ethylene methyl acrylate copolymers (EMA), ethylene methacrylic acid copolymers (EMAA), ethylene ethyl acrylate copolymers (EEA), ethylene acrylic acid copolymers (EAA), polyesters and ionomers are also examples of sealant materials. Suitable sealant materials also include those disclosed in U.S. Pat. Nos. 6,964,816; 6,861 ,127; 6,815,023; 6,773,820; 6,682,825; 6,316,067; 5,759,648; and 5,663,002 and U.S. Patent Application Publications 2005/0129969 and 2004/0166262, each of which is incorporated in its entirety in this application by this reference. Sealant materials may also comprise polyamides such as nylon, polyesters such as polyethylene terephthalate (PET), polystyrene, polycarbonates, cyclic olefin copolymers, polyacrylonitrile or copolymers or blends of such. Specific examples of sealant materials include but are not limited to ethylene alpha-olefin copolymers commercially available from The Dow Chemical Company (Midland, Mich.) under trade names Affinity™, Attane™ or Elite™ (including 1-octene as an alpha-olefin) and from ExxonMobil Chemical Company (Houston, Tex.) under a trade name Exact™ (including 1-hexene, 1-butene and 1-octene as comonomers) and ionomers commercially available from E. I. du Pont de Nemours and Company (Wilmington, Del.) under a trade name Surlyn®.
As used throughout this application, the term “polyethylene” or “PE” refers (unless indicated otherwise) to ethylene homopolymers and copolymers. Such copolymers of ethylene include copolymers of ethylene with at least one alpha-olefin and copolymers of ethylene with other units or groups such as vinyl acetate or otherwise. The term “polyethylene” or “PE” will be used without regard to the presence or absence of substituent branch groups.
As used throughout this application, the term “high density polyethylene” or “HDPE” refers to both (a) homopolymers of ethylene which have densities from about 0.960 g/cm3 to about 0.970 g/cm3 and (b) copolymers of ethylene and an alpha-olefin (usually 1-butene or 1-hexene) which have densities from about 0.940 g/cm3 to about 0.958 g/cm3. HDPE includes polymers made with Ziegler or Phillips type catalysts and polymers made with single-site metallocene catalysts. HDPE also includes high molecular weight polyethylenes. In contrast to HDPE, whose polymer chain has some branching, are “ultra high molecular weight polyethylenes,” which are essentially unbranched specialty polymers having a much higher molecular weight than the high molecular weight HDPE.
As used throughout this application, the term “low density polyethylene” or “LDPE” refers to branched homopolymers having densities between 0.915 g/cm3 and 0.930 g/cm3, as well as copolymers containing polar groups resulting from copolymerization (such as with vinyl acetate or ethyl acrylate). LDPE typically contains long branches off the main chain (often termed “backbone”) with alkyl substituents of two to eight carbon atoms.
As used throughout this application, the term “copolymer” refers to a polymer product obtained by the polymerization reaction or copolymerization of at least two monomer species. Copolymers may also be referred to as bipolymers. The term “copolymer” is also inclusive of the polymerization reaction of three, four or more monomer species having reaction products referred to terpolymers, quaterpolymers, etc.
As used throughout this application, the term “copolymer of ethylene and at least one alpha-olefin” (also referred to as “ethylene-alpha olefin copolymer”) refers to a modified or unmodified copolymer produced by the co-polymerization of ethylene and any one or more alpha-olefins. Suitable alpha-olefins include, for example, C3 to C20 alpha-olefins such as propene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene and combinations of such. The co-polymerization of ethylene and an alpha-olefin may be produced by heterogeneous catalysis, such as co-polymerization reactions with Ziegler-Natta catalysis systems, including, for example, metal halides activated by an organometallic catalyst (e.g., titanium chloride) and optionally containing magnesium chloride complexed to trialkyl aluminum. Heterogeneous catalyzed copolymers of ethylene and an alpha-olefin may include linear low density polyethylene (LLDPE), very low density polyethylene (VLDPE) and ultra low density polyethylene (ULDPE) (commercially available as, for example, Dowlex™ from The Dow Chemical Company (Midland, Mich.)). Additionally, the co-polymerization of ethylene and an alpha-olefin may also be produced by homogeneous catalysis, such as co-polymerization reactions with metallocene catalysis systems which include constrained geometry catalysts, (e.g., monocyclopentadienyl transition-metal complexes). Homogeneous catalyzed copolymers of ethylene and alpha-olefin may include modified or unmodified ethylene alpha-olefin copolymers having a long-chain branched (i.e., 8-20 pendant carbons atoms) alpha-olefin co-monomer (commercially available as, for example, Affinity™ and Attane™ from The Dow Chemical Company (Midland, Mich.)), linear copolymers (commercially available as, for example, Tafmer™ from the Mitsui Petrochemical Corporation (Tokyo, Japan)), and modified or unmodified ethylene alpha-olefin copolymers having a short-chain branched (i.e., 3-6 pendant carbons atoms) alpha-olefin co-monomer (commercially available as, for example, Exact™ from ExxonMobil Chemical Company (Houston, Tex.)). In general, homogeneous catalyzed ethylene alpha-olefin copolymers may be characterized by one or more methods known to those of skill in the art, including but not limited to molecular weight distribution (Mw/Mn), composition distribution breadth index (CDBI), narrow melting point range and single melting point behavior.
As used throughout this application, the term “modified” refers to a chemical derivative, such as one having any form of anhydride functionality (e.g., anhydride of maleic acid, crotonic acid, citraconic acid, itaconic acid, fumaric acid, etc.), whether grafted onto a polymer, copolymerized with a polymer or blended with one or more polymers. The term is also inclusive of derivatives of such functionalities, such as acids, esters and metal salts derived from such.
As used throughout this application, the term “polypropylene” or “PP” refers to a homopolymer or copolymer having at least one propylene monomer linkage within the repeating backbone of the polymer. The propylene linkage can be represented by the general formula: [CH2—CH(CH3)]n.
As used throughout this application, the term “ionomer” refers to a partially neutralized acid copolymer, such as a metal salt neutralized copolymer of ethylene and acrylic or methacrylic acid.
As used throughout this application, the term “polyester” refers to a homopolymer or copolymer having an ester linkage between monomer units which may be formed, for example, by condensation polymerization reactions between a dicarboxylic acid and a diol. The ester linkage can be represented by the general formula: [O—R—OC(O)—R′—C(O)]n where R and R′ are the same or different alkyl (or aryl) group and may be generally formed from the polymerization of dicarboxylic acid and diol monomers containing both carboxylic acid and hydroxyl moieties. The dicarboxylic acid (including the carboxylic acid moieties) may be linear or aliphatic (e.g., lactic acid, oxalic acid, maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and the like) or may be aromatic or alkyl-substituted aromatic (e.g., various isomers of phthalic acid, such as paraphthalic acid (or terephthalic acid), isophthatic acid and naphthalic acid). Specific examples of a useful diol include but are not limited to ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butane diol, neopentyl glycol, cyclohexane diol and the like. Polyesters may include a homopolymer or copolymer of alkyl-aromatic esters including but not limited to polyethylene terephthalate (PET), amorphous polyethylene terephthalate (APET), crystalline polyethylene terephthalate (CPET), glycol-modified polyethylene terephthalate (PETG) and polybutylene terephthalate; a copolymer of terephthalate and isophthalate including but not limited to polyethylene terephthalate/isophthalate copolymer; a homopolymer or copolymer of aliphatic esters including but not limited to polylactic acid (PLA); polyhydroxyalkonates including but not limited to poly hydroxy propionate, poly(3-hydroxybutyrate) (PH3B), poly(3-hydroxyvalerate) (PH3V). poly(4-hydroxybutyrate) (PH4B), poly(4-hydroxyvalerate) (PH4V), poly(5-hydroxyvalerate) (PH5V), poly(6-hydroxydodecanoate) (PH6D); and blends of any of these materials.
As used throughout this application, the term “polystyrene” or “PS” refers to a homopolymer or copolymer having at least one styrene monomer linkage (such as benzene monomer (i.e., C6H5) with an ethylene substituent) within the repeating backbone of the polymer. The styrene linkage can be represented by the general formula: [CH2—CH2(C6H5)]n. Polystyrene may be formed by any method known to a person or ordinary skill in the art.
As used throughout this application, the term “barrier” refers to any material which controls a permeable element of the film, sheet, web, package or otherwise against aggressive agents and includes but is not limited to oxygen barrier, moisture (e.g., water, humidity, etc.) barrier, chemical barrier, heat barrier, light barrier and odor barrier. The term “barrier layer” refers to a layer of the film, sheet, web, package or otherwise which controls such permeable element.
As used throughout this application, the term “ethylene vinyl alcohol copolymer” or “EVOH” refers to copolymers comprised of repeating units of ethylene and vinyl alcohol. Ethylene vinyl alcohol copolymers can be represented by the general formula: [(CH2—CH2)m—(CH2—CH(OH))]n. Ethylene vinyl alcohol copolymers may include saponified or hydrolyzed ethylene vinyl acetate copolymers. EVOH refers to a vinyl alcohol copolymer having an ethylene co-monomer and prepared by, for example, hydrolysis of vinyl acetate copolymers or by chemical reactions with vinyl alcohol. The degree of hydrolysis is preferably at least 50% and, more preferably, at least 85%. Preferably, ethylene vinyl alcohol copolymers comprise from about 28 mole percent to about 48 mole percent ethylene, more preferably, from about 32 mole percent to about 44 mole percent ethylene, and, even more preferably, from about 38 mole percent to about 44 mole percent ethylene. Specific non-limiting examples of EVOH include EVAL™ H171 available from EVAL Company of America (Houston, Tex.); Evasin® EV-3801 V available from Chang Chun Petrochemical Co., Ltd. (Taipei, Taiwan); and Soarnol® ET3803 available from Soarus L.L.C. (Arlington Heights, Ill.). As used throughout this application, the term “polyamide” or “PA” or “nylon” refers to a homopolymer or copolymer having an amide linkage between monomer units which may be formed by any method known to those skilled in the art. The amide linkage can be represented by the general formula: [C(O)—R—C(O)—NH—R′—NH]n where R and R′ are the same or different alkyl (or aryl) group. Examples of nylon polymers include but are not limited to nylon 6 (polyeaprotactam), nylon 11 (polyundecanolactam), nylon 12 (polyauryllactam), nylon 4,2 (polytetramethylene ethylenediamide), nylon 4,6 (polytetramethylene adipamide), nylon 6,6 (polyhexamethylene adipamide), nylon 6,9 (polyhexamethylene azelamide), nylon 6,10 (polyhexamethylene sebacamide), nylon 6,12 (polyhexamethylene dodecanediamide), nylon 7,7 (polyheptamethylene pimelamide), nylon 8,8 (polyoctamethylene suberamide), nylon 9,9 (polynonamethylene azelamide), nylon 10,9 (polydecamethylene azelamide), and nylon 12,12 (polydodecamethylene dodecanediamide). Examples of nylon copolymers include but are not limited to nylon 6,6/6 copolymer (polyhexamethylene adipamide/caprolactam copolymer), nylon 6,6/9 copolymer (polyhexamethylene adipamide/azelaiamide copolymer), nylon 6/6,6 copolymer (polycaprolactam/hexamethylene adipamide copolymer), nylon 6,2/6,2 copolymer (polyhexamet ylene ethylenediamide/hexamethylene ethylenediamide copolymer), and nylon 6,6/6,9/6 copolymer (polyhexamethylene adipamide/hexamethylene azelaiamide/caprolactam copolymer). Examples of aromatic nylon polymers include but are not limited to nylon 4,1, nylon 6,1, nylon 6,6/6I copolymer, nylon 6.6/6T copolymer, nylon MXD6 (poly-m-xylylene adipamide), poly-p-xylylene adipamide, nylon 6I/6T copolymer, nylon 6T/6I copolymer, nylon MXDI, nylon 6/MXDT/I copolymer, nylon 6T (polyhexamethylene terephthalamide), nylon 12T (polydodecamethylene terephthalamide), nylon 66T, and nylon 6-3-T (poly(trimethyl hexamethylene terephthalamide).
As used throughout this application, “polyvinylidene chloride” or “PVDC” refers to copolymers of vinylidene chloride. PVDC may be formed from polymerization of vinylide chloride with various monomers including but not limited to acrylic esters and unsaturated carboxyl groups. Vinylidene chloride copolymers include but are not limited to vinylidene chloride-vinyl chloride copolymers, vinylidene chloride-methyl acrylate copolymers and vinylidene chlortde-acrylonitrile copolymers. Vinylidene chloride copolymer is also known as saran.
As used throughout this application, “metalized film” and “metal-oxide coated film” refer to any thermoplastic material upon which is deposited a layer of metal or metal oxide. Examples of thermoplastic materials include polyolefin resins such as polyethylene, polypropylene, polyisoprene, polybutene, poly-3-methyl-1-butene, poly-4-methyl-1-pentene, polybutadiene, polystyrene and copolymers of constituent monomers of the foregoing polymers (e.g. ethylene propylene copolymer; linear low density polyethylenes containing 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene or the like as a comonomer; block copolymer of propylene and ethylene; styrene butadiene copolymer and mixtures, graft products, cross-linked products, block copolymers, etc.), ethylene vinyl acetate copolymer and its saponification products, halogen-containing polymers (e.g. polyvinylidene chloride, polyvinyl chloride, polyvinyl fluoride, polyvinylidene fluoride, polychloroprene, chlorinated rubber, etc.), polymers of unsaturated carboxylic acids and their derivatives (e.g. polyalkyl methacrylate, polyalkyl acrylate, polyacrylonitrile, copolymers of constituent monomers of the foregoing polymers with other monomers, such as acrylonitrile styrene copolymer, ABS resins, ethylene alkyl acrylate copolymer, ethylene glycidyl methacrylate copolymer, ethylene methacrylic acid copolymer and its ionic cross-linked products, etc.), polyacetal, polycarbonate, polyester (e.g. polyethylene terephthalate, polybutylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide, polyphenylene oxide, polysulfone, etc. Among these thermoplastic materials, polyester, polypropylene and polyamide may be preferred for the metalized film in the multilayer film described in the present application. The metal or metal oxide deposited as a layer on the thermoplastic material may be composed of any suitable metal. Layers may be simple metals, such as aluminum, titanium, chromium, nickel, zinc, copper, bronze, gold, silver, or alloys of such, or may be metal oxides such as aluminum oxide, silicon oxide, ferrite, indium oxide, etc. The metals and metal oxides may be deposited as a layer on a surface of the thermoplastic material according to procedures known to a person of ordinary skill in the art. Such procedures include but are not limited to electroplating, sputtering and vacuum vapor-deposition. The thickness of the metal or metal oxide deposited may be about 20 to about 1000 Angstroms.
As used throughout this application, the term “oriented” refers to a film, sheet, web or otherwise which has been elongated in at least one of the machine direction or the transverse direction. Such elongation is accomplished by procedures known to a person of ordinary skill in the art. Non-limiting examples of such procedures include the single bubble blown film extrusion process and the slot case sheet extrusion process with subsequent stretching, for example, by tentering, to provide orientation. Another example of such procedure is the trapped bubble or double bubble process. (See, for example, U.S. Pat. Nos. 3,546,044 and 6,511,688, each of which is incorporated in its entirety in this application by this reference.) In the trapped bubble or double bubble process, an extruded primary tube leaving the tubular extrusion die is cooled, collapsed and then oriented by reheating, reinflating to form a secondary bubble and recooling. Transverse direction orientation may be accomplished by inflation, radially expanding the heated film tube. Machine direction orientation may be accomplished by the use of nip rolls rotating at different speeds, pulling or drawing the film tube in the machine direction. The combination of elongation at elevated temperature followed by cooling causes an alignment of the polymer chains to a more parallel configuration, thereby improving the mechanical properties of the film, sheet, web, package or otherwise. Upon subsequent heating of an unrestrained, unannealed, oriented article to its orientation temperature, heat-shrinkage (as measured in accordance with ASTM Test Method D2732, “Standard Test Method for Unrestrained Linear Thermal Shrinkage of Plastic Film and Sheeting,” which is incorporated in its entirety in this application by this reference) may be produced. Heat-shrinkage may be reduced if the oriented article is first annealed or heat-set by heating to an elevated temperature, preferably to an elevated temperature which is above the glass transition temperature and below the crystalline melting point of the polymer comprising the article. This reheating/annealing/heat-setting step also provides a polymeric web of uniform flat width. The polymeric web may be annealed (i.e., heated to an elevated temperature) either in-line with (and subsequent to) or off-line from (in a separate process) the orientation process.
As used throughout this application, the term “tie material” refers to a polymeric material serving a primary purpose or function of adhering two surfaces to one another, presumably the planar surfaces of two film layers. For example, a tie material adheres one film layer surface to another film layer surface or one area of a film layer surface to another area of the same film layer surface. The tie material may comprise any polymer, copolymer or blend of polymers having a polar group or any other polymer, homopolymer, copolymer or blend of polymers, including modified and unmodified polymers (such as grafted copolymers) which provide sufficient interlayer adhesion to adjacent layers comprising otherwise nonadhering polymers. As a non-limiting example, pattern-applied adhesive may be preferred for the tie material between the exterior layer and the interior layer in the multilayer film described in the present application.
As used throughout this application, the term “duct” refers to a channel, conduit, canal, passage, passageway or the like.
As used throughout this application, the term “registered” refers to the placement of a component. In the multilayer film and package described in the present application, various channels and/or passages may be registered. As such, in forming a package, various channels and/or passages may be located in the body of the package, not fully or solely contained by a seal or seals of the package.
Referring now to the drawings, with elements depicted as illustrative and not necessarily to scale and with the same (or similar) reference numbers denoting the same (or similar) features throughout the drawings,
In
As shown in
Interior layer 66 may be a sealant layer and may comprise sealant material, as described and defined above. Interior layer 66 may be a multilayer film. A non-limiting example of such interior multilayer film comprises a first layer of polyethylene, a second layer of polyethylene and a third layer of polypropylene. Another non-limiting example of an interior multilayer film comprises a first layer of sealant material (as described and defined above) and a second layer of polyester. A further non-limiting example of an interior multilayer film comprises a coextruded polypropylene/polyethylene, with a first layer of polypropylene and a second layer of polyethylene.
Exterior layer 60 may be a barrier layer and may comprise barrier material. Examples of barrier material include but are not limited to ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyester, polypropylene, polyamide, metalized film, metal-oxide coated film, foil, nanocomposite, polyvinytidene chloride, polyglycolic acid, polyacrylonitrile, polyalkylene carbonate, methyl acrylate copolymer, polyethylene or blends of the above. Exterior layer 60 may be a multilayer film. A non-limiting example of such exterior multilayer film comprises a first layer of polyester and a second layer of foil, metalized film or metal-oxide coated film. Another non-limiting example of an exterior multilayer film comprises a first layer of polyester, polypropylene or polyamide and a second layer of ethylene vinyl alcohol copolymer. A further non-limiting example of an exterior multilayer film comprises a first layer of polyethylene, a second layer of polyethylene, a third layer of ethylene vinyl alcohol copolymer, a fourth layer of polyethylene and a fifth layer of polyethylene. An additional non-limiting example of an exterior multilayer film comprises a first layer of polyethylene or polypropylene, a second layer of polyamide, a third layer of ethylene vinyl alcohol copolymer, a fourth layer of polyamide and a fifth layer of polyethylene or polypropylene.
Considering the examples of interior multilayer films and exterior multilayer films described above, non-limiting examples of various structures for multilayer film 10 include the following (with “/” used to denote the layer boundaries and with components of the exterior multilayer film listed first)
Additionally, for any structure of multilayer film 10 (again, not limited to the example structures described above), any aperture or apertures formed in interior layer 66 do not adversely affect barrier properties of multilayer film 10. For example, any aperture or apertures in interior layer 66 terminate at interior layer inner surface 68, do not continue into exterior layer 60 and/or do not extend beyond exterior layer inner surface 62.
Referring again to the drawings,
In the figures and the above description, the multilayer film of the present application is shown and described as including up to three channels and as including one passage. However, the multilayer film may comprise any number of channels (and corresponding apertures) and any number of passages. The number of channel(s) and passage(s) is limited only by the dimensions of the multilayer film and the dimensions of the channel(s) and the passage(s). The channel(s) may be of any length, as measured from channel first end to channel second end or as measured from channel first are to channel second area, and the passage(s) may be of any length, as measured from passage first end to passage second end (e.g., from the first edge of the multilayer film to the opposing second edge of the multilayer film). As a non-limiting example, the channel(s) may have a length of from about 0.5 centimeters to about 10 centimeters, as measured from channel first end to channel second end or as measured from channel first area to channel second area. The channel(s) and the passage(s) may be of any width, and the width may vary from one area to another. As a non-limiting example, a channel may have the same width at the channel first area and the channel second area, as depicted in the figures. As an alternative non-limiting example, the channel first area may have a wider width (e.g., to allow for wider gas escape) than the channel second area. If multiple channels are present, a first channel may have a different length and/or width from a second channel; a second channel may have a different length and/or width from a third channel; a third channel may have a different length and/or width from a fourth channel; and so on. Similarly, if multiple passages are present, a first passage may have a different width from a second passage; however, each passage will have the same length (i.e., extending laterally from the first edge of the multilayer film to the opposing second edge of the multilayer film).
Additionally, in the figures, the channels and the passage are shown as straight. However, the channel(s) and/or the passage(s) may bend or otherwise be non-linear (e.g., wavy, zigzag, etc.). Furthermore, the channel(s) and/or the passage(s) may be placed in the transverse direction, the machine direction and/or neither (e.g., diagonal across both directions). Provided the multilayer film comprises a valve (with at least one aperture, at least one channel and at least one passage) allowing for fluid communication from an interior layer outer surface to an external atmosphere and provided each intersection of a channel and a passage occurs at an angle greater than 0 degrees and less than 180 degrees, the placement and location of the channels ) and the passage(s) are limited only by the dimensions and end-use of the film. As a non-limiting example, a person of ordinary skill in the art may determine the dimensions of the channel(s) and the passage(s) based, in part, on the product to be packaged, the gas volume generated by the product and the corresponding gas volume to be discharged to the external atmosphere. As a further non-limiting example (and as further described below), if the film is to be used as a package, the location of each channel and passage is such that each channel (e.g., first channel 22, first channel 22 and second channel 42, or first channel 22, second channel 42 and third channel 52) and each passage (e.g, passage 28) is registered, i.e., placed on the film so that it will be in the body of the package, not solely in a seal or seals of the package.
Also, depending on the end-use of the film, silicone, mesh and/or other material may be placed in the channel(s) and/or the passage(s) to improve valve operation.
The multilayer films described above may be made by a variety of methods. One non-limiting example of a method of making the multilayer film is as follows. A first layer comprising thermoplastic polymer materials is provided as the exterior layer, and a second layer comprising thermoplastic polymer materials is provided as the interior layer to be adjacent to the exterior layer. As described above, the first layer and the second layer may each be a monolayer film or a multilayer film and may each be a cast film, a blown film, an extrusion-coated film, a laminated film or any other film known to a person of ordinary skill in the art. The bonded and non-bonded portions are then provided between the interior layer and the exterior layer. Such portions may be provided by the use of pattern-applied adhesive or by any other method known to a person of ordinary skill in the art. The provision of the non-bonded portion also forms the channels) (e.g., first channel 22, first channel 22 and second channel 42, or first channel 22, second channel 42 and third channel 52) and the passage(s) (e.g., passage 26).
Next, the aperture(s) (e.g., first aperture 20, first aperture 20 and second aperture 40, or first aperture 20, second aperture 40 and third aperture 50) are provided in the interior layer. As described above, mechanical means, optical ablation (e.g., laser) or other methods known to a person of ordinary skill in the art may be used to form a hole, vent, score, slit, slot, perforation, puncture, orifice, opening, inlet or otherwise in the interior layer. For example, the aperture or apertures may be made by scoring the interior layer with a score-line extending laterally from a first edge of the multilayer film to an opposing second edge. The score-line has a depth extending from an outer surface of the interior layer to an inner surface of the interior layer. A first aperture, first and second apertures, first, second and third apertures, first, second, third and fourth apertures, etc. may each be a section of the score-line. As noted above, any aperture is made so as to not adversely affect any barrier properties of the multilayer film. For example, any aperture or apertures in the interior layer terminate at the inner surface of the interior layer, do not continue into the exterior layer and/or do not extend beyond the inner surface of the exterior layer.
In general, multilayer films for packaging may be produced using a web with repeating patterns or units that then form individual packaging units. Referring again to the drawings,
As depicted in
For package 120c, first channel 22 extends laterally from first wall 126c to second wall 128c of package 120c. In other words, first channel 22 wraps around from one side of package 120c to the other. In this embodiment, first aperture 20 is in first wall 126c of package 120c. Passage 28, first channel second area 26, first channel second end 27 and first channel-passage intersection point 34 is each in second wall 128c of package 120c.
As mentioned above, other embodiments of the multilayer film may be used to form packages. For example, if multilayer film 10b of
As depicted in
In the embodiment shown in
The packages described above may be formed by a variety of methods. One non-limiting example of a method of forming a package is depicted in
Second sealing assembly 214 is then used to form second seal 134. (The arrows adjacent second sealing assembly 214 in
Following the formation of second seal 134, an amount of product is introduced into funnel 204 such that product is provided in the product receiving chamber. The filled, semi-sealed, in-process package 120 is then moved off of second end 216 of elongated tubular portion 208, such that it is supported only by web 110. (The arrow adjacent package 120 in
A first area of a first outlet and a second area of a first outlet may each be formed in first seal 122 or a second outlet may be formed in second seal 134 and a third outlet may be formed in third seal 38. As described above, such outlets are intended to be in fluid communication with ends of the passage. As such, such outlets may be gaps, interruptions or other non-sealed areas of first seal 122, second seal 134 and/or third seal 138. Such gaps or other non-sealed areas may be formed by the use of a skip in the seal bar(s) in first sealing assembly 212 and/or second sealing assembly 214. Such gaps or other non-sealed areas may also be formed based on material selection (i.e, the materials forming the outer surfaces of the exterior layer and/or interior layer of the multilayer film) or by any other method known to a person of ordinary skill in the art.
In forming package 120, VFFS machine 200 is adjusted with undue experimentation by a person of ordinary skill in the art such that none of first seal 122, second seal 134 or third seal 138 fully contains any channel(s) or passage(s) in final package 120; however, as described above, first seal 122, second seal 134 or third seal 138 may intersect channel(s) and/or passage(s). In other words, each channel and/or passage is registered, i.e., located in the body of package 120 and not solely in first seal 122, second seal 134 or third seal 138.
The above description, examples and embodiments disclosed are illustrative only and should not be interpreted as limiting. The present invention includes the description, examples and embodiments disclosed; but it is not limited to such description, examples or embodiments. Modifications and other embodiments will be apparent to those skilled in the art, and all such modifications and other embodiments are intended and deemed to be within the scope of the present invention as defined by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| PI1003492-7 | Sep 2010 | BR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US11/52311 | 9/20/2011 | WO | 00 | 10/15/2013 |
