The present invention relates to food packages and particularly to vertical form fill seal and horizontal form fill seal pouches suitable for use in applications where the food product must undergo a retort or aseptic process while remaining inside the package.
It is common practice in packaging many goods, including food items, to use what is generally known as form-fill-seal equipment. In the vertical form-fill-seal arrangement, flexible packaging material is fed from a rollstock to a tube former where a tube is fashioned from the web material into a vertically dependent, upwardly open tube having overlapping longitudinal edges. These overlapping edges are subsequently sealed together longitudinally and the end of the tube is sealed together by a pair of transverse heat seals which are vertically spaced apart. At this point the tube is filled with a measured quantity of the product to be packaged. Often, the packaging material may be squeezed in some cases so that the air in the headspace of the pouch is eliminated. Shortly thereafter, a second heat sealing operation, typically performed after the filled tube has been downwardly advanced, completes enclosure of the product. Simultaneously with or shortly after the transverse heat sealing step the tube is completely transversely severed by cutting in a space between the vertically spaced apart pair of transverse heat seals. Finally, the tube is downwardly advanced and the cycle is successively repeated so as to form a multiplicity of individually packaged products.
In recent years, continuous vertical form-fill-seal packaging machines with constant motion of the packaging web through the packaging machine have become available to the packaging industry. The packaging operation is performed on a continuously moving web without interrupting moving packaging web. Continuous vertical form-fill-seal packaging machines provide a significant higher output compared to intermittent operation machines because the packaging web does not need to stop when the forming, filling and sealing operations are performed. Typically, a lap-type or butt-type seal is used to form the longitudinal back-seam of the package in order to minimize the total amount packaging web that must be sealed through and because of the relatively short dwell times associated with the sealing operation. These seals must have sufficient seal strength in order to resist the physical and mechanical abuse imposed by the form-fill-seal process.
In order to store food without refrigeration, a food product may be sterilized by a hot fill operation during packaging, aseptic processing or a retort operation after packaging the product. Sterilization by hot filling or retorting imposes several restrictions on the choice of materials for the package. The heat seals of the package must survive sterilization temperatures of over 71° C. (160° F.) or typical retort conditions of steam or water at 121° C. (250° F.) or more under pressure for one half hour or more. The seals of package need to have sufficient seal strength to resist the shearing and/or compression forces resulting from the relatively high temperatures and pressures during the sterilization process. Furthermore, the packaging materials must not delaminate, shrink, or wrinkle as a result of the sterilization. Oxygen and water barrier properties of the packaging material must not be adversely affected by the conditions of sterilization or by the contents of the package. Conventional hot fill or retort pouches are not vertical form-fill-seal pouches, but rather stand-up pouches or three or four-sided sealed formed with fin-type seals. It is generally recognized by those skilled in the art that hot fill or retort pouches formed with lap-type or butt-type seals will expose a cross-section of the packaging web to the contents of the package. This exposed cross-section of the packaging film is unprotected and liquids from within the package can leach into the film structure through the exposed cross-section. The barrier properties of these packages may easily deteriorate when acidic beverages or foodstuffs, such as tomato paste and other tomato products interact with the various materials used to construct the packaging web. Pinholes in a foil or metal oxide layer can be created by oxidation in connection with these undesirable interactions. Delamination between the laminate layers can also occur because the acid in some beverages or foodstuffs chemically degrades the adhesive bond holding these layers together. Furthermore, ink layers may also delaminate from the surface of a film after chemically interacting with acidic liquids of the package contents.
Opening of the finished package can create a safety issue when tools such as scissors or knives are used to gain access to the packaged contents. Notwithstanding the risk of being injured by these tools by accidentally cutting or puncturing oneself or others, these tools may also introduce the risk of contamination from one package to another when multiply packages are opened at the same time. Thus, to mitigate these risks, it would be desirable fabricate packages that do not require the use of scissors or knives to open package.
Thus, there is a need in the art for improved packages that address at least some of the above concerns, and which are simple in construction, can be made easily and inexpensively manufactured,
The present invention is concerned with easy-open packages for packaging beverages and wet food products for use with form-fill-seal machines, especially vertical form-fill-seal machines, and/or under hot fill or retort sterilization conditions. The inventive packages are formed from a web of a film comprising an oxygen barrier. The package includes a frangible first seal connecting the first side of the web to the second side of the web which defines a tube member having an inner surface, an outer surface, a first package wall, a second package wall, opposing first and second package edges, a first package end and an opposing second package end. The package further comprises a second seal provided through the first and second package walls and extending laterally across the width of both the first and second package walls at a position proximate the first package end, and a third seal provided through the first and second package walls and extending laterally across the width of both the first and second package walls at a position proximate the second package end, whereby defining a product receiving chamber by the first package wall, the second package wall, the second seal and the third seal. The frangible first seal exposes a cross-sectional edge of the multilayer film inside the product receiving chamber which is protected by a protective strip frangibly sealed to the inner surface of the tube member and covering the exposed cross-sectional edge of the multilayer film.
One particularly useful feature of the packages of the present invention is its usefulness in packaging food products currently packaged in No. 10 metal cans. These cans are expensive and bulky, and present significant inbound freight costs due to the weight of the cans, significant warehouse space issues for can inventory, and a disposal problem after use of the contained food product. Utilizing the material's of the present invention, many food products now packaged in the No. 10 can may be conveniently and quickly packaged, stored for an extended period of time, shipped, marketed, and sold to the end user such as a commercial or institutional user or a consumer. After use, the emptied package of the present invention provides a much less bulky and expensive package for disposal.
FIG, 7 illustrates a fragmentary cross-sectional view taken along lines A-A of
The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
A preferred embodiment of the package of the present invention is made from a web 10 of a film 11 having a first side edge 12a and opposing, second side edge 12b connected by a third side edge 12c and a fourth side edge 12d. First side edges 12a and second 12b are preferably parallel to each other when film 11 is in a long flat planar state. Third side edge 12c and fourth side 12d are preferably parallel to each other when film 11 is in a lay flat planar state. First and second side edges 12a, 12b are also preferably perpendicular to third and fourth side edges 12c, 12d when film 11 is in a lay flat planar state. Film 11 has four corners at the intersections of the four sides with first corner 12ac defined by the junction of first side edge 12a with third side edge 12c; second corner 12b defined by the junction of first side edge 12a with third side edge 12c; second corner 12bc defined by the junction of second side edge 12b with third side edge 12c; third corner 12ad defined by the junction of first side edge 12a with fourth side edge 12d; and fourth corner 12bd defined by the junction of second side edge 12b with fourth side edge 12d. Film 11 has a top surface 13a circumscribed by a perimeter 14 formed by sides 12a, 12c, 12b and 12d with an opposing bottom surface 13b also circumscribed by said perimeter 14.
Referring now to
Frangible lap seal 16 is preferably a heat seal forming a peelable fusion bond between surface 13a and surface 13b of film 11. The overlapped sealed film 11 defines a tube member 18 having an inner film surface 19 of said tube member 18. Connecting first package edge 22 and second package edge 23 defines a first package wall 30 and connected opposing package wall 31. A second seal 20 extends laterally across said tube member 18 adjacent the third side edge 12c of film 11 thereby forming a closed package end 21. A variety of seals may be used. Preferably second seal 20 will be a heat seal which fusion bonds the pouch film inner surface 19 to itself The second seal 20 by closing package end 21 both forms a first package edge 22 and opposing second package edge 23, and the second seal extends across the tube member 18 from the first package edge 22 to the second package edge 23. The second seal may also employ a variety of shapes, thicknesses, structures, etc, as for the previously described lap seal 16. The frangible lap seal does not need to be centered between edges 22 and 23 but preferably is positioned anywhere therebetween.
As noted above,
As also noted above,
A protective strip SO is tangibly sealed to the inner surface 19 of the tube member 18 extending along the entire length of lap seal 16 such that the exposed first side edge 12a of film 11 is entirely covered by said strip. The frangible seal 51 of strip 50 is preferably formed by heat to produce a peelable fusion seal between an outer surface 52 of the strip and the inner surface 19 defined by parallel spaced apart dotted lines 17c and 17d. Also, the width of the strip may be varied to be thicker or thinner as desired. Strip 50 may optionally be frangibly sealed to inner surface 19 by alternatives or additional means, including. e.g., by applications of suitable glue or adhesive material known in the art far sealing together films. Preferably, strip 50 is formed from multilayer film 11a and includes an inner surface 53 which is adapted to form a non-peelable heat seal to inner surface 19 of tube member 18.
At least the first seal 16 of package 15 and seal 51 protective strip 50 each comprise a frangible seal. “Frangible seal” and like terminology is used herein to refer to a seal, and especially heat seals, which are engineered to be readily peelable without uncontrolled or random tearing or rupturing the packaging materials which may result in premature destruction of the package and/or inadvertent contamination or spillage of the contents of the package. A frangible seal is one that can be manually peeled and/or fractured apart to open the package at the seal without resort to a knife or other implement to open the package. In the present invention, the frangible seal must have a seal strength sufficient to prevent failure of the seal during the normal hot fill and/or retort process and further normal handling and transport of the packaged article. The seal strength must also be low enough to permit manual opening of the seal. Preferably seal parameters such as choice of materials and sealing conditions will be used to adjust the seal strength to the desired level for the particular package and application. The frangible seals of the present invention may have peelable seal strengths of between 100 grams and 2000 grams, or between 200 grams and 1500 grams, or between 200 grams and 1200 grams. In contrast, non-peelable seals have seal strengths greater than 2000 grams, or greater than 2500 grams, or greater than 3000 grams. Typically, the end seals of the present invention are non-peelable.
Many varieties of peelable seals are known in the art and are suitable for use with the present invention. Peelable seals are generally made from thermoplastic films having a peelable system designed therein. Suitable peelable films and/or peelable systems are disclosed in U.S. Pat. No. 4,944,409 (Busche et al.); U.S. Pat. No. 4.875, 587 (Lulham et al.); U.S. Pat. No. 3,655,503 (Stanley et al.); U.S. Pat. No. 4,058,632 (Evans et al.); U.S. Pat. No. 4,252,846 (Romesberg et al.); U.S. Pat. No. 4,615.926 (Hsu et al.) U.S. Pat. No. 4,666,778 (Hwo); U.S. Pat. No. 4,784,885 (Carespodi); U.S. Pat. No. 4,882,229 (Hwo); U.S. Pat. No. 6,476,137 (Longo); U.S. Pat. No. 5,997,968 (Dries, et al.); U.S. Pat. No. 4,189,519 (Ticknor); U.S. Pat. No. 5,547,752 (Yanidis): U.S. Pat. No. 5,128,414 (Hwo); U.S. Pat. No. 5,023,121 (Pockat, et al.); U.S. Pat. No. 4,937,139 (Genske,et al.); U.S. Pat. No. 4,916,190 (Hwo); U.S. Pat. No. 4,550,141 (Hoh); U.S. Pat. No. 7,314,669 B2 (Galloway) and U.S. Pat. No. 8,147,934 B2 (Berbert), the disclosures of which are incorporated herein in their entirety by reference thereto, Preferred films for use in fabricating packages according to the invention may be selected from multilayer, shrinkable or non-shrinkable films capable of forming a peelable seal. In one preferred embodiment, at least one heat-sealing layer is peelable and/or fracturable and comprises a blend of at least two resins selected from the group consisting of polyethylene, polypropylene, polybutene, ethylene butene copolymer, ethylene vinyl acetate copolymer, propylene ethylene copolymer, ethylene acrylic acid copolymer, ethylene n-butyl acrylate, ethylene methyl acrylic acid copolymer, and ethylene methylacrylate copolymer. In another preferred embodiment, a layer adjacent to and in contact with one of the heat-sealing layers is peelable and/or fracturable and comprises a blend of at least two resins selected from the group consisting of polyethylene, polypropylene, polybutene, ethylene butene copolymer, ethylene vinyl acetate copolymer, propylene ethylene copolymer, ethylene acrylic acid copolymer, ethylene n-butyl acrylate, ethylene methyl acrylic acid copolymer, and ethylene methylacrylate copolymer. It is also contemplated that at least one heat sealing layer and the layer adjacent to and in contact with said heat sealing layer are each peelable and/or fracturable and comprises a blend of at least two resins selected from the group consisting of polyethylene, polypropylene, polybutene, ethylene butene copolymer, ethylene vinyl acetate copolymer. propylene ethylene copolymer, ethylene acrylic acid copolymer, ethylene n-butyl acrylate, ethylene methyl acrylic acid copolymer, and ethylene methylacrylate copolymer.
Preferred films may also provide a beneficial combination of one or more or all of the below noted properties including high puncture resistance (e.g.. as measured by the ram and/or hot water puncture tests), low shrinkage values, low haze, high gloss, high seal strengths and printability. Since the inventive packages may advantageously be used to hold oxygen or moisture sensitive articles, it is preferred to use a thermoplastic film which includes an oxygen and/or moisture barrier layer. The terms “barrier” or “barrier layer” as used herein means a layer of a multilayer film which acts as a physical barrier to moisture or oxygen molecules.
It is particularly preferred to include an oxygen barrier material in the film used in the present invention. Oxygen barrier materials which may include, but are not limited to, ethylene vinyl alcohol copolymers (EVOH), polyacrylonitriles, polyamides and vinylidene chloride copolymers (PVDC). For some applications, the oxygen barrier material may also include metal foils, such as aluminum foil and barrier coatings deposited onto a polymer layer such as silica, alumina and the like. The phrase “barrier coating” refers to a coating that may be applied to one or both surfaces of a film by any known method such as sputtering, vacuum deposition or electroplating (all of which involve some act or method of “depositing” a continuous inorganic material, metal, metal oxide, metal alloy, silicon or silicon oxide layer onto the surface of a polymer substrate). The metal used can vary, though aluminum, zinc, gold, silver or appropriate alloys of such are preferred, with aluminum or aluminum-containing alloys being particularly preferred. As will be recognized by those skilled in the art, while the metal coating predominantly consists of the identified metal (such as aluminum), amounts of other additives may be present to improve assorted physical and optical properties of the deposited metal layer. In some occasions, pure aluminum (or the metal of choice) may be used. Other additives maybe used in minor amounts such that aluminum (or the metal of choice) is the major component. Vacuum deposition is a preferred method of metallization in terms of processing and cost. Preferred values for the average thickness of the metal coating layer are within the range of about 1.0 to 100 nanometers, with the preferred average thickness being within the range of about 3 to 25 nanometers. (1 micron equals 10-7 meters, and 1 nanometer equals 10-8 meters.) Regardless, the metal coating preferably has a thickness less than the polymer substrate on which it is deposited, preferably substantially less than said substrate. In contrast. typical metal foils used in packaging film application have a thickness of between 4.3 to 150 microns, as noted in “Foil, Aluminum” in The Wiley Encyclopedia of Packaging Technology, 2nd. Ed., by Foil Division of the Aluminum Association, Inc., pp. 458-463, which is incorporated herein by reference. For an aluminized coating layer, the key conditions are optical density (metal deposition) of approximately 0.75 to 4, preferably 1.0-3.0.
In accordance with the present invention, the oxygen barrier material in the film provides the package with an oxygen transmission rate of less than about 1.0 cm3/100 in2/24 h at 73° F., 0% RH and 1 atm (or about 15.5 cm3/m2/24 h at 23° C., 0% RH and 1 atm), preferably, less than about 0.5 cm3/100 in2/24 h at 73° F. 0% RH and 1 atm (or about 7.75 cm/m2/24 h at 23° C., 0% RH and 1 atm), and most preferably, about 0.2 cm3/100 in2/24 h at 73° F. 0% RH and 1 atm (or about 3.1 cm3/m2/24 h at 23° C., 0% RH and 1 atm).
In accordance with the present invention, the multilayer, barrier film for use in forming packages may be either heat shrinkable or non-heat shrinkable. In this application, the term “heat shrinkable” means that a film has an unrestrained shrinkage of at least 10% in each of the transverse direction (TD) and machine direction (MD) measured at 90° C. (194° F.), Preferably, a heat shrinkable film has an unrestrained shrinkage of at least 20% in each direction and most preferably the shrink is at least 40% or more in both directions. Measuring the unrestrained shrink value of a thermoplastic film is accomplished by a procedure described below, which is derived from ASTM D2732. In contrast, the term “non-heat shrinkable” means that a film has an unrestrained shrinkage of less than 20% in each of the transverse direction (TD) and machine direction (MD) measured at 90° C. (194° F.). Preferably, a non-heat shrinkable film has an unrestrained shrinkage of less than 15% in each direction and most preferably is less than 10% or more in both directions.
A preferred multilayer, barrier film for use in forming packages according to the present invention is illustrated in
Another preferred multilayer, barrier film for use in forming packages according to the present invention is illustrated in
In the above-illustrated structure, it is also contemplated that film 11 may include both an outer surface peelable and/or fracturable heat sealing layer, and a peelable and/or fracturable layer in contact with said heat sealing layer.
A preferred multilayer film for use in forming protective strip 50 according to the present invention is illustrated in
Another preferred multilayer film for use in forming protective strip 50 according to the present invention is illustrated in
In the above-illustrated structure, it is also contemplated that film 11a may include both an outer surface peelable and/or fracturable heat sealing, and a peelable and/or fracturable layer in contact with said heat sealing layer.
Turning now to
Another embodiment of the present invention is illustrated in
The following examples illustrate certain particular embodiments of films suitable for use in forming packages and protective strips and are not to be interpreted as limiting. In the following example, resin composition percentages are based on the total weight of each film layer.
A package according to the present invention, as generally illustrated in
The total thickness of film 500 was about 5.95 mils.
Film 600 had the folio ng structure and layer compositions.
A package according to the present invention was made, as generally described above for Example 1 with films 500 and 600, except for film layers 501 and 502 of film 500 had the following structure and layer compositions:
Layer 501 (Sealant): 99 wt.-% polypropylene copolymer (PP)-Pro-fax SA861 (LyondellBasell Industries Holdings, B.V., The Netherlands)+1.0 wt.-% processing additives
Layer 502 (Peelable): 81 wt.-% ethylene vinyl acetate copolymer (EVA)-DuPont™ Elvax® 3135X (E.I. du Pont de Nemours and Company, Inc., Wilmington, Del., USA)+19 wt.-% polybutene-1 (PB)-PB 8640M (LyondellBasell Industries Holdings, B.V , The Netherlands)
The packages according to the invention are preferably fabricated continuously from a continuous web or roll stock. The roll stock is slit to a desired width and fed into a bag making equipment, wherein the first and second sides of the packaging film are brought together to form a tube member in a lap-type or butt-type tape seal configuration. Simultaneously, a tape of protective strip film is fed to the inside surface of the tube member so that the first, second sides and protective strip film are sealed together longitudinally by a set of hot sealing jaws, to form a continuous single-seamed tube, or tube member having the protective strip covering the inside surface of the lap-type or butt-type tape seal. Alternatively, the first and second sides of the film may be sealed together longitudinally first followed by sealing of the protective strip of the seal over the lap-type or butt-type tape seal on the interior surface of the tube member. In yet another alternative method, the protective strip may first be pre-tacked to the edge of one side of the film prior to forming the tube member. The first and second sides of the packaging film are then brought together to form a tube member in a lap-type or butt-type tape seal configuration, followed by simultaneously sealing the first side, the second side and protective strip film together as a single-seam. In either case, an additional overlap portion is provided when the first and second sides of the film are brought together that will act as a pull flap. One or more tear notches or cuts on the outer edges of the pull flag may be added to assist with opening of the package. A second seal is provided transversely across the entire width of the tube member at a desired location spaced from the open mouth of the tube which defines a first “end seal” of the package. A food product is then introduced into the open mouth of the tube member to a desired volume. Stripper jaws then engage the film effectively stripping any food product from the area above the food product. The stripping process ensures that there is substantially zero head space inside the package between the contents of the package and the final seal. Following this process, a third seal is formed thereby hermetically closing the package. The third seal defines the second “end seal” of the package. A parallel, spaced apart, transverse cut is made within the area of the third seal to separate the package product. The length of the package can easily be varied by changing the distance between transverse seals and cuts. The width of the packages can also by easily varied by changing the width of the film by slitting the standard rollstock.
Filing Document | Filing Date | Country | Kind |
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PCT/US14/18132 | 2/25/2014 | WO | 00 |