Foldover condiment package film

Abstract

Foldover squeeze packages for containing flowable material generally have a first sidewall and a second sidewall that are sealed to each other around their respective perimeters. The second sidewall has an outlet that permits the flowable material to exit the package. A portion or flap of the package is folded over and sealed directly to itself around the outlet. Films for forming such foldover squeeze packages include a first film and a second film. The second film has at least first and second layers, wherein the second layer is adapted for use as an interior surface of a second sidewall a squeeze package and the second layer is adapted to seal to itself without disrupting the seal between the sidewalls of the package.

Description

TECHNICAL FIELD

[0001] The present invention relates to films for forming foldover squeeze packages. More particularly, the inventive films are capable of forming a package that is folded over and sealed to itself around an outlet for the contents of the package.

BACKGROUND OF THE INVENTION

[0002] Various attempts have been made to provide a dispenser package in which a flowable product may be packaged in the quantity normally required for single or multiple uses, and from which the contained product may be dispensed. One type of such dispenser packages is a pillow package or sachet, typically made of relatively thin plastics and foils or combinations of laminated plastics and foils. These packages are most frequently encountered as containers for catsup, mustard, other condiments, homecare preparations such as hair conditioners, dyes and cremes.

[0003] Although this type of package is universally used, it is often difficult to access the contents of the package. To obtain access to the contents, the package must be held in one hand while a tearing motion and force are applied by the other hand. Creating the initial tear to break the package's seal can be difficult, often requiring the assistance of the user's teeth. Moreover, once the initial tear is created, the laminated foil and/or plastic material often tears in an uncontrolled fashion. In addition, the holding pressure exerted by one of the user's hands often forces the contents out of the envelope not only before the user is ready to apply the contents, but even before the tearing motion is complete.

[0004] The user must also use both hands to open the container. In the case of invalids, arthritis sufferers and other handicapped people, opening these packages is virtually impossible. Further disadvantages include the package's inability to function effectively with low viscosity products such as coffee cream, mouthwash or alcoholic beverages, due to the inability of the torn opening to control the direction of flow of such liquids from the package. These packages also are generally totally unrecyclable, and therefore become environmental pollutants. As above-mentioned however, should continued use of these packages be preferred, then the easy opening feature of this application may be readily and economically adhered to the package to make for an easy opening, reclosable, high-barrier package.

[0005] An easy to open package is disclosed in U.S. Patent Publication No. 2001/0030192 filed by Redmond, which is hereby incorporated by reference. The package disclosed in Redmond is a foldover squeeze package that can be sealed or adhesively attached over a small pre-made outlet aperture. The package may be made of polypropylene, high-density polyethylene, PVC or polyester. However, the package may require adhesive to seal the package to the outlet aperture which adds to the expense of manufacturing the package. Also, if adhesive is applied in the incorrect location on the film, the film may be incapable of folding over and sealing to itself.

[0006] Alternatively, the package may seal directly to itself without adhesive. However, the temperature required to seal the package to itself is too high, the heat can disrupt the seal between the sidewalls or cause the interior walls of the package to seal together. Therefore, what is needed are films capable of forming a package similar to the package disclosed in Redmond and forming a peelable seal without adhesive at a temperature that does not disrupt the integrity of the package.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide films that are capable of forming a foldover squeeze package without the use of adhesive between the flap of the package and the package sidewall.

[0008] It is a further object of the present invention to provide films that are capable sealing together to provide two sidewalls of a package.

[0009] Additionally it is an object of the present invention to provide films capable of forming a package that when folded over itself, can seal to itself, providing a peelable seal without disrupting the integrity of the package.

[0010] Additionally, it is an object of the present invention to provide films that form a package with a sidewall capable of sealing to itself, providing a peelable seal that is adapted to be weak enough to be manually pulled apart but sufficiently strong to remain closed during shipping and storage.

[0011] The films are adapted to form a foldover squeeze package without the use of adhesive. The foldover package is designed to contain a flowable material and to dispense the material in a controlled fashion. The foldover squeeze package has an outlet which dispenses the flowable material in a controlled fashion. Before opening, the outlet is sealed by a portion or flap of the package which has been folded over and sealed around the package. When access to the contents is desired, the consumer lifts the flap, automatically exposing the outlet.

[0012] The films of the present invention are capable of forming such an easy to open squeeze package without requiring localized adhesive to seal the flap around the outlet. The packages may be formed on high speed production equipment that typically forms several packages across a given width of film. The packages are formed and filled in lanes.

[0013] The packages have a first sidewall and a second sidewall that are sealed together around their perimeters. The second sidewall defines an outlet, such as an aperture or a series of perforations formed in the sidewall. The package is folded over itself and the second sidewall is sealed directly to itself around the outlet. The second sidewall is capable of heat sealing to itself in a peelable seal that allows the package to be manually unfolded, automatically exposing the outlet. If a series of perforations is used to form the outlet, unfolding the package will automatically tear the second sidewall at the perforations, creating an aperture.

[0014] The first sidewall is formed of a first film with an inner skin layer that faces the interior of the package. The second sidewall is formed of a second film with an inner skin layer that faces the interior of the package. The inner skin layers are capable of being sealed to each other in a permanent seal to form the sidewalls. The inner skin layers are formed of materials such as ionomer, low density polyethylene (LDPE), linear low density polyethylene (LLPDE), linear medium density polyethylene (LMDPE), metallocene polyethylene (mPE), or blends thereof. Alternatively, the inner skin layers may be formed of any copolymer of polypropylene or polyester.

[0015] The second film has a composition that provides an exterior skin layer capable of sealing directly to itself providing a peelable seal. The composition of the exterior skin layer enables the exterior skin layer to form a peelable seal at a temperature lower than the temperature at which the sidewalls are sealed together. In one embodiment, the exterior skin layer has a sealing temperature of at least about 8° F. (4° C.) less than the sealing temperature of the material in the inner skin layers. In another embodiment, the exterior skin layer composition has a sealing temperature that is at least about 30° F. to about 100° F. less than the sealing temperature of the material in the inner layers. Because of this temperature difference, the peelable seal may be created without disrupting the seal between the sidewalls. The peelable seal is sufficiently weak to be pulled apart manually, but is sufficiently strong to withstand shipping and storage without opening.

[0016] As mentioned above, the exterior skin layer is formed of a material capable of sealing at a lower temperature than the material in the inner skin layers. Suitable examples of materials for the exterior skin layer include ionomer, polypropylene, ethylene vinyl acetate, linear low density polyethylene, low density polyethylene, ethylene acrylic acid, ethylene methacrylic acid copolymer, metallocene polyethylene or blends thereof. If the exterior skin layer of the second film and the inner skin layers of the film are of the same type of polymer, the polymer of the exterior skin layer is selected to have a lower melt point, and, thus a lower sealing temperature, than the material in the inner skin layers. For example, ionomer resin may be used in both the exterior skin layer and the inner skin layers. However, the ionomer resin selected for the exterior skin layer has a lower melting point than the ionomer resin for the inner skin layers.

[0017] In one embodiment, a weakening agent is included in the exterior skin layer to provide peelable properties to a seal between the exterior skin layer and itself. Such an agent weakens the seal between the exterior skin layer and itself, increasing the peelability of the seal. Examples of materials that can be used to create peelability include polybutene, talc, ionomers in polyethylene and other incompatible materials in a base resin. Peelable seals through delamination, cohesive, or adhesive failure are all examples of the concept.

[0018] Additional aspects and advantages of this invention will be apparent from the following detailed description of additional embodiments thereof, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a perspective view of a foldover squeeze package with an outlet shown in a dotted line.

[0020] FIG. 2 is a perspective view of the same package illustrated in FIG. 1 before the top portion of the package has been folded over.

[0021] FIG. 3 is a perspective of the package shown in FIG. 2 with the top portion folded over.

[0022] FIG. 4 is a cross section view of a flap portion of the package shown in FIGS. 1-3.

[0023] FIG. 5 is a partial, perspective view with a perforated score line forming a tab, before the package has been folded over itself.

[0024] FIG. 6 is a partial perspective view of the package shown in FIG. 5 with the tab torn open after the package has been unfolded.

[0025] FIG. 7 depicts a first film of the present invention.

[0026] FIG. 8 depicts a second film of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] The present invention relates to improved films for foldover squeeze packages that are easily opened and easy to use. The improved films are adapted to form squeeze packages similar to the packages disclosed in U.S. Patent Publication No. 2001/0030192, incorporated by reference above. The squeeze packages are designed to contain a flowable material and to dispense the materials in a controlled fashion. Examples of flowable materials include condiments such as ketchup, shampoo, syrups, salad dressings, confectionery items, candy, hand cream, liquid detergents, motor oil, toothpaste and pet food. The squeeze package is capable of dispensing the flowable food or beverages directly into the mouth of the user.

[0028] The films of the present invention are capable of forming an easy to open squeeze package without requiring localized adhesive. The package is formed of a first film and a second film that are sealed to each other around the perimeter of the pouch, forming the sidewalls of the pouch. The film compositions are selected so that the pouch can be folded over itself and sealed around an outlet without disrupting the seal between the two sidewalls and without sealing the sidewalls together.

[0029] The films may be manufactured from a number of suitable thermoplastic materials and are capable of forming foldover squeeze packages in high speed packaging equipment. The packaging equipment is adapted to form several packages across a given width of film. Polymers useful in the first and second film are defined below.

[0030] As used herein, the term “ethylene vinyl acetate copolymer” (EVA) refers to a copolymer formed from ethylene and vinyl acetate monomers wherein the ethylene derived units (monomer units) in the copolymer are present in major amounts by weight and the vinyl acetate in the copolymer is present in minor amounts by weight.

[0031] As used herein, the term “ionomer” refers to ionomer class materials and include selected molecular weight grades of copolymers such as ethylene/methacrylic acid or ethylene/acrylic acid combined with a metal salt, such as zinc, sodium or lithium, then acid neutralized to create ion clusters. Ionomer resins available from DuPont under the tradename Surlyn are examples of suitable ionomers.

[0032] As used herein, the term “ethylene/alpha-olefin copolymer” refers to any product prepared by the copolymerization of ethylene and any one or more alpha-olefins. Typically, the alpha-olefin is a C3-C20 alpha-monoolefin, more typically, a C4-C8 alpha-monoolefin. In one embodiment, the alpha-olefin may comprise at least one member selected from the group consisting of 1-butene, 1-hexene, and 1-octene, respectively.

[0033] As used herein, the term “metallocene polyethylene” (mPE) refers to any polyethylene manufactured using a single site (e.g. metallocene) catalyst. Metallocene polyethylene is typically ethylene/alpha olefin copolymer.

[0034] As used herein, the phrase “low density polyethylene” (LDPE) refers to ethylene homopolymer having a density ranging from about 0.91 g/cm3 to about 0.925 g/cm3. LDPE is typically produced using conventional high pressure process.

[0035] As used herein, the phrase “linear low density polyethylene” (LLDPE) refers to ethylene alpha-olefin copolymers having a density ranging from about 0.915 g/cm3 to about 0.94 g/cm3. LLDPE can be manufactured using a conventional Ziegler Natta catalyst or a single site catalyst, such as metallocene.

[0036] As used herein, the phrase “linear medium density polyethylene” (LMDPE) refers to ethylene alpha-olefin copolymers having a density ranging from about 0.925 g/cm3 to about 0.94 g/cm3. LMDPE can be manufactured using conventional Ziegler Natta catalysts or single site catalysts, such as metallocene.

[0037] As used herein, the phrase “high density polyethylene” (HDPE) refers to ethylene alpha-olefin copolymers or ethylene homopolymer having a density of about 0.94 g/cm3 or greater. HDPE can be produced with several classes of catalysts, such as Ziegler-Natta catalysts and metallocene catalysts.

[0038] As used herein, the term “polybutene” refers to those polymeric entities comprised of butene and another monomeric unit such as ethylene, propylene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene units, with the butene monomeric unit comprising the major component of the copolymer. This polymer is sometimes referred to as polybutylene.

[0039] As used herein, “ethylene vinyl alcohol copolymer” (EVOH) includes saponified or hydrolyzed ethylene vinyl acetate copolymers, and refers to a vinyl alcohol copolymer having an ethylene comonomer. EVOH is typically prepared by, for example, hydrolysis of vinyl acetate copolymers, or by chemical reactions with polyvinyl alcohol. The degree of hydrolysis is typically greater than about 50% and more typically greater than about 85%.

[0040] As used herein, “polypropylene” refers to those polymeric entities that are propylene homopolymers and propylene copolymers. Propylene copolymers comprise propylene copolymerized with a lesser amount of another monomeric unit, typically ethylene.

[0041] As used herein, the phrase “tie layer” refers to any internal layer, of a multilayer film. A tie layer may be used between two layers to adhere the two layers to one another.

[0042] FIG. 1 illustrates a perspective view of one embodiment of a squeeze package 10 with a first sidewall 30 and a second sidewall 40. The second sidewall 40 defines an outlet 20 shown in dotted lines. The first and second sidewalls are joined together along three edges, filled with liquid or other flowable product and sealed along a fourth edge.

[0043] As shown in FIG. 1, a portion or flap 50 of the squeeze package is folded over and sealed in a peelable seal to the second sidewall of the package. The second sidewall is capable of adhering directly to itself to form the peelable seal. As used herein, the “directly adhered” is defined as adhesion of one film layer to itself or another film layer, without the use of adhesive. When access to the contents of the package is desired, the flap is peeled away, automatically exposing the outlet for the flowable material.

[0044] FIG. 2 illustrates a perspective view of the squeeze package shown in FIG. 1 before the flap of the squeeze package is folded over and sealed to the second sidewall of the package. The outlet of the squeeze package shown in FIGS. 1-3 is a hole 20 that has been punched into the second sidewall of the package. When a portion of the squeeze package is folded over, the folded over portion or flap is sealed to the area of the second sidewall defining hole 20, as shown in FIG. 4. The flap is sealed to the package sidewall so that the flap can be manually unfolded to expose the hole.

[0045] In another embodiment, shown in FIGS. 5-6, the second sidewall 40 of the package contains a fault line score pattern that forms a tab 60. In this embodiment, the flap 50 is folded over and sealed to the area inside the score pattern so that when the flap 50 is unfolded, the tab is torn away from the second sidewall 40 at the score pattern and an outlet 20′ is created. Such score lines may be created by laser cuts and may be made in increments of less than a thousandth of an inch deep in thin films. Alternatively, instead of being formed by perforations, the tab 60 may be cut into the sidewall. In another embodiment, the outlet may be spout. The flap may be folded over and sealed around the spout.

[0046] The first sidewall comprises a first film and the second sidewall comprises a second film. A cross section of an embodiment of first film 100 with seven layers is illustrated at FIG. 7. First film 100 includes an inner skin layer 122 that is adapted to provide an interior surface of the package. First film 100 further includes an exterior skin layer 110 that is adapted to provide an exterior surface of a package. The first film also includes five core layers 112, 114, 116, 118, 120. While the first film is described as having multiple layers, the first film may be a single layer film containing only the inner skin layer.

[0047] A cross section of an embodiment of second film 200 with seven layers is illustrated at FIG. 8. The second film generally comprises at least two layers, an exterior skin layer and an inner skin layer. As used herein, the term exterior skin layer refers to a layer that forms an exterior surface, such as layer 210, of the squeeze package and the term inner skin layer refers to a layer that forms an interior-facing surface of the squeeze package, such as layer 222. The embodiment shown in FIG. 8 includes five core layers 212, 214, 216, 218, 220.

[0048] The relative sealing temperatures of resins useful in the films are discussed below. The melting temperatures of the resins making up a film sealing layer determine the layer's sealing temperature. Three conditions affect the creation of a seal: time, temperature and pressure. A film layer will begin to seal to itself when the layer itself approaches the melting temperature, but before the melting temperature is reached. Thus the sealing temperature is a temperature at or below the melting temperature. However, note that to create a seal in a desired amount of time, the manufacturing equipment may be set at a temperature setting higher than the sealing temperature. It may also be desirable to allow the sealing layer to reach a temperature about 10° F. to about 20° F. above the sealing temperature to ensure a complete seal. For embodiments in which it is desirable to “overshoot” the sealing temperature in this manner, materials for the inner skin layers and the exterior skin layer should be selected to provide the exterior skin layer with a sealing temperature of at least about 20° F. to about 30° F. less than the sealing temperature of the inner skin layers. The resins appropriate for use in the exterior skin layer and the inner skin layers are discussed in more detail below.

[0049] The composition of the inner skin layer of the first film and the composition of the inner skin layer of the second film are selected to allow the inner skin layers to be heat sealed together in a permanent seal on packaging equipment. The inner skin layers are sealed around the perimeter of the sidewalls to form the package. The temperature for sealing the inner skin layers together is referred to herein as the sidewall sealing temperature or first sealing temperature. In one embodiment, the first sealing temperature ranges from about 200° F. (93° C.) to about 280° F. (138° C.). In another embodiment, the first sealing temperature ranges from about 210° F. (99° C.) to about 280° F. (138° C.).

[0050] In one embodiment, the compositions of the inner skin layers are identical. Alternatively, the inner skin layers may have compositions that differ from each other as long as the layers are heat sealable to each other at the desired temperature. The inner skin layers may contain thermoplastic polymers such as ionomer, ethylene vinyl acetate, polypropylene, ethylene/alpha olefins, copolymer polyester and blends thereof. Suitable ionomer resins include those available from Dupont, under the tradename Surlyn, such as product numbers 1857, AD9464-3, 1705, 1650, 1652 and 1601. Suitable ethylene/alpha olefin resins include LDPE, mPE, LDPE, LLDPE, and LMDPE. In one embodiment, the inner skin layers comprise LLDPE with a melt index ranging from about 0.5 to about 6.0. LLDPE resins with a high melting temperature can be selected. For example, commonly available LLDPE resins melt at about 250° F. or higher. These resins are useful in embodiments in which it is desirable to have the inner skin layers seal at a temperature over 20° F. greater than the sealing temperature of the exterior skin layer.

[0051] In another embodiment, the inner skin layers comprise ionomer with melt index ranging from about 0.5 to about 6.0. Examples of suitable LLDPE resins include those available from Dow Chemical Company (“Dow”) under the tradename Dowlex, such as product numbers 2045G, 2256H and 2056G, and those available from Huntsman under the tradename REXell, such as product number 8101. Another suitable LLDPE resin is available from Nova under the tradename NOVAPOL. LDPE with a melt index ranging from about 0.5 g/10 minutes to about 6.0 g/10 minutes may alternatively be used for the inner skin layers. Suitable examples of LDPE resins include those available from Equistar under the tradename Petrothene M2520; those available from CPChem under the tradename Marlex or Marflex; those available from Eastman under the tradenames HIFOR and MXSTEN. An example of a suitable mPE resin is the resin available from Dow under the tradenames and product numbers Affinity PL1850 and Elite 5100G. Other suitable mPE resins are sold by Exxon Mobil under the tradenames and product numbers Exact 3132 and 3131 and Exceed 1018CA. Suitable polypropylene polymers include propylene homopolymer and copolymers having a melt index ranging from about 3 g/10 minutes to about 12 g/10 minutes. Examples of suitable polypropylene copolymer resins for use in the inner skin layers are the resins available from Montel under the tradename SA861 and from Exxon under the tradename and product number Escorene PD9012E1. Inner skin layers containing polypropylene may also contain additives, such as the additive available from Ampacet under the product number 701402. Suitable copolymer polyester resins include those sold by Eastman under the tradename Eastobond and those sold by Dupont.

[0052] The exterior skin layer or second layer of the second film is adapted for use as an exterior surface of the squeeze package. In addition, the exterior skin layer has a composition that permits the layer to seal to itself to form a peelable seal. As used herein a peelable seal refers to a seal that is sufficiently weak to be peeled apart manually but remains intact during storage and until ready for use. A peelable seal is generally a seal that can be peeled apart with the application of force equal to less than three pounds per linear inch. The exterior skin layer further comprises a composition that is capable of forming this peelable seal at a temperature below the sidewall sealing temperature so that the peelable seal may be formed without affecting the integrity of the seal between the first and second sidewalls and without sealing the sidewalls to each other.

[0053] The exterior skin layer comprises a heat activated resin. The exterior skin layer may also comprise a weakening agent, such as polybutene, to give the peelable seal the desired peelability. In one embodiment, the exterior skin layer has a composition that enables the layer to seal with itself at a temperature that is at least about 8° F. (4° C.) below the sidewall sealing temperature. In another embodiment, the exterior skin layer is capable of forming a seal with itself at a temperature that is at least about 20° F. less than the sidewall sealing temperature. In another embodiment, the heat activated resin forms a seal at a temperature that is at about 30° F. (10° C.) to about 100° F. (16° C.) less than the sidewall sealing temperature. In one embodiment, the exterior skin layer seals to itself at a temperature that is at least about 30° F. (17° C.) less than the sidewall sealing temperature. In yet another embodiment, the exterior skin layer has a composition selected to enable the exterior skin layer to seal to itself at a temperature at least about 50° F. (28° C.) less than the sidewall sealing temperature. The seal is typically formed between two portions of the exterior skin layer at temperatures ranging from about 150° F. (66° C.) to about 260° F. (127° C.). The specific sealing temperature depends on the composition of the exterior skin layer.

[0054] Suitable heat activated resins include EVA, LDPE, mPE, LLDPE, ethylene acrylic acid, polyethylene, ethylene methacrylic acid, polypropylene or blends thereof. Ionomer is a preferred polymer for use as a heat activated resin in the exterior skin layer. Ionomer with a melt index ranging from about 0.5 g/10 minutes to about 6.0 g/10 minutes may be used in the exterior skin layer. Suitable examples of ionomer include those discussed above in connection with the exterior layer. EVA copolymer resin containing between 4.5 and 23% by weight vinyl acetate with a melt index ranging from about 0.5 g/10 minutes to about 6.0 g/10 minutes may be used in the exterior skin layer. Suitable examples of EVA resins include those available from Dupont under the tradenames Elvax 3170 and 3169 and those available from Equistar under the tradename 720.01. Polypropylene having a melt index ranging from about 3 g/10 minutes to about 12 g/10 minutes may be used in the exterior skin layer. Examples of suitable polypropylene resins include those discussed above in connection with the inner skin layers.

[0055] As mentioned above, the exterior skin layer composition is selected to seal to itself at a temperature below the sidewall sealing temperature. In embodiments of the films where the inner skin layers comprise LLDPE with a seal temperature of about 252° F. (122° C.), examples of suitable polymer resins for the exterior skin layer in this embodiment include: ionomer, a blend of ionomer and polybutene a blend of EVA and polybutene; and a blend of ionomer, EVA and polybutene. An exterior skin layer comprising a blend of EVA and polybutene forms a peelable seal at about 185° F. (85° C.). An exterior skin layer comprising ionomer or a blend of ionomer, EVA and polybutene forms a peelable seal at about 200° F. (93° C.). A blend of ionomer and with polybutene forms a peelable seal at about 190° F.

[0056] In one embodiment, the inner skin layers comprise LLDPE with a melt index ranging from about 0.5 to about 6.0 and which seals at a temperature of about 252° F. The exterior skin layer comprises about 90% ionomer, 5% polybutene, 5% slip/antiblock additive and seals at a temperature of about 190° F.

[0057] For an inner skin layer of LDPE with a melt index ranging from about 0.5 to about 6.0, which seals at a temperature of 225° F. (107° C.), examples of suitable polymer resins for the exterior skin layer include ionomer, EVA, and mPE with a melt index ranging from about 0.5 to about 6.0. Each of these polymers is selected to have a sealing temperature below about 210° F. (99° C.).

[0058] For an inner skin layer of ionomer with a melt index ranging from about 0.5 to about 6.0 which seals at a temperature of 208° F. (98° C.), examples of suitable polymer resins for the exterior skin layer include ionomer, EVA and mPE, each having a melt index ranging from about 0.5 to about 6.0 and a sealing temperature about 10° F. to about 20° F. less than the sealing temperature of the sidewall sealing temperature.

[0059] As discussed above, the exterior skin layer may further contain any weakening agent known in the art to weaken a film layer, so that a seal between the exterior skin layer and itself has the desired level of peelability. As discussed above, the seal is sufficiently weak so that it may be manually pulled apart, but sufficiently strong so that it remains intact during storage and shipping. Suitable examples of weakening agents include polybutene, talc, ionomers, mica, silica and polypropylene. For example, the exterior skin layer could comprise any of the following: ionomer blended with ethylene polymer; ionomer with ethylene copolymers such as ethylene vinyl acetate, ethylene methylacrylate, and polybutene with polyethylene, mPE, ethylene copolymers or ionomer; polypropylene blended into polyethylene, mPE or polyethylene copolymers; any one of talc, mica or silica blended into ionomer, polyethylene, mPE, or ethylene copolymers. In one embodiment, the exterior skin layer contains an amount of polybutene ranging from about 3% to about 30% by weight of the exterior skin layer. In embodiments with an exterior skin layer containing ionomer, the exterior skin layer may contain polybutene in an amount up to about 15% by weight of the exterior skin layer. In embodiments with an exterior skin layer containing EVA, the exterior layer may contain polybutene in an amount ranging from about 10% to about 30% by weight. In another embodiment, the exterior skin layer contains EVA in an amount ranging from about 15% to about 20% by weight of the layer.

[0060] Suitable examples of polybutene resins include polybutene-1 such as those available from Basell under the tradenames PB1600SA and PB8640. The exterior skin layer may further contain additives such as antiblock, slip and other additives known in the art.

[0061] The first film and second film may have additional layers that are positioned as core layers. The compositions of the additional core layers depend on the properties desired for the squeeze package. For example, the first and second films may have one or more layers of a material such as EVOH, polypropylene homopolymer, polypropylene copolymer, HDPE, MDPE, polyamide (nylon), polyester (“PET”), polyvinylidene chloride (“PVDC”) and liquid crystalline polymer. An EVOH layer may be used to provide the film with oxygen barrier properties. One or more polypropylene layers may be used provide the film with moisture barrier properties. HDPE or MDPE layers may be used to provide stiffness. Polyamide or polyester layers may be used to provide the film with toughness and oxygen barrier properties. PVDC or liquid crystalline layers may be used provide moisture and oxygen barrier properties. Other properties may also be obtained through such layers. Examples of suitable HDPE resins include those available from CPChem under the tradename Marlex LX2419, 9662, 9659; and those available from Equistar under the tradenames Alathon M6210, L15885, M6020. Examples of suitable EVOH resins include those available from Nippon Gohsei under the tradenames Soarnol DC3203F and ET 3803; and those available from Eval Company of America under the tradenames F101B and H101B. An example of a polypropylene homopolymer resin suitable for a barrier layer includes the resin available from Amoco under the tradename 10-6721, with a melt index of 7.0 g/10 minutes and a density of 0.900 g/cm3. If polypropylene is used in the barrier layer, the barrier layer may also contain a small amount of additive, such as clarifying agents, slip additive, antiblock or other additives know in the art. An example of a suitable additive is the additive available from Milliken under the tradename 8C41-10. In one embodiment, the barrier layer contains additive in an amount less than about 10% by weight of the barrier layer. In another embodiment, the barrier layer contains additive in an amount less than about 5% by weight of the barrier layer.

[0062] In addition, the first film may also have an exterior-facing surface layer of polymers such as HDPE, MDPE, polypropylene, PET or polyamide to enable the film to receive printing.

[0063] One or more of the layers in each film may contain white concentrate such as TiO2. In embodiments of the films containing HDPE layers, the white concentrate may be included in each HDPE layer in an amount ranging up to about 40% by weight of the HDPE layer. White concentrate provides the film with light barrier properties. White concentrates are typically loaded with up to about 90% by weight titanium dioxide. Suitable white concentrates include those available from Ampacet under the tradename 110359. The film may also contain other concentrates known to provide alternate colors or light barriers, such as red color or black for light barrier.

[0064] The first and second film may further include tie layers to adhere two layers to one another. For films containing polyethylene, suitable tie layer materials include maleic anyhydride grafted polyethylene, anhydride grafted ethylene vinyl acetate and LLDPE based maleic anhydride grafted polyethylene. Suitable resins for use in the tie layers include those available from Dupont under the tradenames Bynel 4104 and 41E529; and those available from MSI under the tradename Plexar 360E. In the case of a film containing a barrier layer of polypropylene homopolymer, a suitable tie layer may be a layer of polypropylene copolymer, such as the resin available from Fina under the tradename Z9470. In addition, the first film may have an exterior-facing surface layer of HDPE or polypropylene to enable the film to receive printing.

[0065] The inventive films may have any thickness suitable for the desired properties of the film. Films used in packages containing a flowable product, typically have a thickness ranging from about 1 mil (25 micron) to about 4 mils (102 micron), more typically from about 2 mils (51 micron) to about 3 mils (76 micron). The skin layers should have sufficient thickness to provide the desired sealing strength and uniformity. In one embodiment, the skin layers have thickness of at least about 0.1 mil (2.5 microns). In another embodiment, the skin layers have a thickness of about 0.6 mil (15 micron). Each skin layer may comprise at least about 5% of the total film thickness. For example, in an embodiment of the second film with seven layers, with film layers represented by the construction A/B/C/D/E/F/G, the film layers have corresponding percentage thicknesses as follows: 20/20/6/10/6/15/23.

[0066] The films in accordance with the present invention can be manufactured using film fabrication technologies well-known in the art. For example, all of the film layers may be coextruded using cast film or blown film manufacturing techniques. Alternatively, the exterior skin layer may be formed by solvent deposition or lamination or lamination to the film. However, one method of manufacture of the multilayer film of the present invention is via simultaneous coextrusion, of all the layers of the multilayer film.

[0067] The films in accordance with the present invention can be use to form foldover squeeze packages without any additional adhesive applied to the film. The films are also capable of forming a package with a sidewall that can be peelable sealed to itself without disrupting the integrity of the package itself.

EXAMPLES

Example 1

[0068] A sample package was prepared from two films, each with seven layers coextruded in a blown film process. The second film had a film construction as identified below in Table A. 1 TABLE A % % By Wt. of Melt Layer Thickness Polymer Type Layer Index Density A 20.0% ionomer 90.0% 1.6 0.950 slip/antiblock 5.0% 25.0 0.960 Polybutene 5.0% 1.0 0.910 B 20.0% HDPE 65.0% 1.0 0.963 white concentrate 35.0% 1.6 2.030 C 6.0% LLDPE-maleic 100%.0% 2.0 0.925 anhydride D 10.0% EVOH 32% 100.0% 3.2 1.190 E 6.0% LLDPE-maleic 100.0% 2.0 0.925 anhydride F 15.0% 65.0% 1.0 0.963 white concentrate 35.0% 1.6 2.030 G 23.0% LLDPE 77.0% 1.0 LDPE 20.0% 2.0% 0.925 slip/antiblock 3.0% 1.080

[0069] The first film had a film construction that was the same as the construction described above for the second film, except that the A layer of the second film comprised 65% by weight of HDPE and 35% by weight white concentrate.

[0070] A package was prepared from the two films, with the LLDPE layers (the G layers) of the first and second films sealed together at 252° F. (122° C.) to create first and second sidewalls. This seal was permanent and would not peel without tearing the film. The second sidewall contained an outlet aperture that was closed off by a flap. The flap was a folded over portion of the package and a peelable seal was created around the outlet aperture by sealing the ionomer/polybutene layer (A layer) of the second sidewall to itself. The peelable seal was formed at 190° F. (88° C.) and did not affect the seal between the sidewalls of the package. The peelable seal formed by the second film peeled with the application of less than 2.5 lbs/in (0.43 kg/cm). The peelable seal of the second sidewall provided good retention of seal strength over time.

Example 2

[0071] A package was prepared of two films, each with seven layers coextruded in a blown film process. The first film was the same as the first film identified for Example 1. The second film was the same as the second film identified in Example 1 except that the A layer comprised 56% ionomer, 33% EVA, 6% slip/antiblock and 5% polybutene. The package was prepared as described above in Example 1.

[0072] The LLDPE layers of the first and second films were sealed together at 252° F. (122° C.) to create first and second sidewalls. The seal between the LLDPE layers was sufficiently strong that it would not peel without tearing the film. The second sidewall contained an outlet aperture that was closed off by a flap. The flap was a folded over portion of the package and a peelable seal was created around the outlet. The second film formed this seal at a temperature of about 190° F. (93° C.) without affecting the integrity of the seal between the LLDPE layers. The peelable seal formed by the second film peeled with the application of less than 2.5 lbs/in (0.43 kg/cm). The peelable seal of the second sidewall provided good retention of seal strength over time.

Example 3

[0073] A package was prepared of two films, each with seven layers coextruded in a blown film process. The first film was the same as the first film identified for Example 1. The second film was the same as the second film identified in Example 1 except that the A layer comprised ionomer. The package was prepared as described above in Example 1.

[0074] The LLDPE layers of the first and second films were sealed together at 252° F. (122° C.) to create first and second sidewalls. The seal between the LLDPE layers was sufficiently strong that it would not peel without tearing the film. The second sidewall contained an outlet aperture that was closed off by a flap. The flap was a folded over portion of the package and a peelable seal was created around the outlet. The second film formed this seal at a temperature of about 200° F. (93° C.) without affecting the integrity of the seal between the LLDPE layers. The peelable seal formed by the second film peeled with the application of less than 2.5 lbs/in (0.43 kg/cm). The peelable seal of the second sidewall provided good retention of seal strength over time.

Example 4

[0075] A package was prepared of two films, each with seven layers coextruded in a blown film process. The first film was the same as the first film identified for Example 1. The second film was the same as the second film identified in Example 1 except that the A layer comprised EVA and polybutene. The package was prepared as described above in Example 1.

[0076] The LLDPE layers of the first and second films were sealed together at 252° F. (122° C.) to create first and second sidewalls. The seal between LLDPE layers was permanent would not peel without tearing the film. The second film was directly sealed to itself in a peelable seal at a temperature of 185° F. (85° C.) without affecting the integrity of the seal between the LLDPE layers. The peelable seal formed by the second film peeled with the application of less than 2.5 lbs/in (0.43 kg/cm). The peelable seal of the second sidewall provided sufficient retention of seal strength over time for closing off the outlet aperture during storage and shipping.

Example 5

[0077] A package was prepared of two films prepared in a cast film process. The compositions and structure of the two film are described in Tables A and B. As used in Tables A and B, clarifying agent refers to an additive available from Milliken Chemical under the tradename 8C41-10 and slip additive refers to an additive available from Ampacet under the product number 7012402. The first film had the structure and composition as identified below in Table B. 2 TABLE B % % By Wt. of Layer Thickness Polymer Type Layer Melt Index Density A 25.0% polypropylene 99 7.0 0.906 clarifying agent 1 B   50% polypropylene 99 1.0 0.963 clarifying agent 1.0% 1.6 2.030 C 25.0% MPE 92.8 3.0 0.902 polypropylene 3.2 6.0 0.900 slip additive 2.2 4.0 0.919

[0078] The second film had the structure and composition identified below in Table C. 3 TABLE C Layer Percent of Resin Layer Percent Polymer Type Layer Melt Index Density A 20.0% 18% EVA 70.0 1.5 0.940 Polybutene 15.0 4.0 0.908 Polypropylene 15.0 6.0 0.900 B 5.0% Polypropylene 100.0% 5.0 0.890 C 50.0% Polypropylene 99.0% 7.0 0.900 clarifying agent 1.0 0.900 D 25.0% MPE 92.8 3.0 0.906 Polypropylene 3.2 6.0 0.900 slip additive 4.0% 2.2 0.919

[0079] The first film and the second film were oriented so that the C layer of the first film and the D layer of the second film were positioned adjacent to each other. The C layer of the first film and the D layer of the second film were sealed to each other to form a perimeter of a package at a temperature of about 207° F. (97° C.). The package was folded over itself and so that the A layer sealed to itself. The A layer formed a peelable seal with itself at a temperature of about 185° F. (85° C.). The peelable seal of the second sidewall provided sufficient retention of seal strength over time for closing off the outlet aperture during storage and shipping.

[0080] It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.

Claims

1. Films for forming a foldover squeeze package used to contain flowable materials such as condiments, wherein the package has a first sidewall and a second sidewall that are sealed to each other around their respective perimeters, wherein the second sidewall has an outlet that permits the flowable material to exit the package and wherein a portion of the package is folded over so that the second sidewall is sealed to itself around the outlet; the films comprising:

a first film for forming a first sidewall of a squeeze package, the first film having at least an inner skin layer providing an inner facing surface adapted for use as an interior surface of a first sidewall of a squeeze package,

a second film for forming a second sidewall of a squeeze package, the second film having at least two layers, including an inner skin layer that is adapted for use as an interior surface of a second sidewall of a squeeze package and an exterior skin layer that is adapted for use as an exterior surface of a second sidewall of a squeeze package,

wherein the exterior skin layer contains a heat activated resin,

wherein the inner skin layer of the second film is capable of sealing at its surface to the inner skin layer of the first film at a first sealing temperature to form a perimeter of a squeeze package,

wherein the exterior skin layer of the second film, when sealed directly to itself, is capable of forming a peelable seal at a second sealing temperature below the first sealing temperature without affecting the integrity of the seal between the first and second sidewalls,

wherein the exterior skin layer layer, when sealed to itself at a second temperature, forms a peelable seal that is sufficiently weak to be peeled apart manually and that is sufficiently strong to remain sealed during storage and until ready for use.

2. The films as claimed in claim 1, wherein the heat activated resin comprises at least one polymer selected from the group consisting of polypropylene, ethylene/alpha olefin, ethylene vinyl acetate, ethylene methylacrylate copolymer, polyethylene, ethylene methyl acrylic acid and blends thereof.

3. The films as claimed in claim 1, wherein the heat activated resin comprises ionomer.

4. The films as claimed in claim 1, wherein the exterior skin layer of the second film contains a weakening agent.

5. The films as claimed in claim 4, wherein the weakening agent is selected from the group consisting of ionomer blended with polyethylene; ionomer with ethylene vinyl acetate; ionomer blended with ethylene methylacrylate; polypropylene blended with polyethylene; talc; mica; and silica.

6. The films as claimed in claim 4 wherein the weakening agent is polybutene.

7. The films as claimed in claim 1 wherein the exterior skin layer contains polybutene in amount ranging from about 3% to about 30% by weight of the exterior skin layer.

8. The films as claimed in claim 1, wherein the inner skin layer of the first film comprises the same composition as the inner skin layer of the second film.

9. The film as claimed in claim 1, wherein the inner skin layer comprise linear low density polyethylene.

10. The films as claimed in claim 1, wherein the inner skin layers comprise at least one polymer selected from the group consisting of ionomer, low density polyethylene, linear low density polyethylene, linear medium density polyethylene, metallocene catalyzed polyethylene and copolymer polyester.

11. The films as claimed in claim 1, wherein the second sealing temperature is at least about 8° F. below the first sealing temperature.

12. The films as claimed in claim 1, wherein the second sealing temperature is at least about 20° F. below the first sealing temperature.

13. The films as claimed in claim 1, wherein the second sealing temperature is at least about 30° F. below the first sealing temperature.

14. The films as claimed in claim 1, wherein the second sealing temperature is at least about 50° F. below the first sealing temperature.

15. The films as claimed in claim 1, wherein the first sealing temperature ranges from about 200° F. to about 280° F. and the second sealing temperature ranges from about 150° F. to about 260° F., wherein the second temperature is at least about 20° F. below the first sealing temperature.

16. The films as claimed in claim 1, wherein the inner skin layers comprise linear low density polyethylene and wherein the exterior skin layer comprises a polymer blend selected from the group consisting of: a blend of ethylene vinyl acetate and polybutene; and a blend ethylene vinyl acetate and polybutene.

17. The films as claimed in claim 1, wherein the inner skin layers comprise linear low density polyethylene and wherein the exterior skin layer comprises ionomer.

18. The films as claimed in claim 1, wherein the inner skin layer comprise linear low density polyethylene and wherein the exterior skin layer comprises a blend of ionomer and polybutene.

19. The films as claimed in claim 1, wherein the inner skin layers comprise ionomer and wherein the exterior skin layer comprises a polymer or polymer blend selected from the group consisting of: ionomer; and a blend of ethylene vinyl acetate and metallocene catalyzed polyethylene.

20. The films as claimed in claim 1, wherein the inner skin layers comprise a blend metallocene catalyzed polyethylene and polypropylene and the exterior skin layer comprises a blend of EVA, polybutene and polypropylene.

21. The films as claimed in claim 1, wherein the inner skin layers comprise a blend of LLDPE and LDPE and the exterior skin comprises layer a blend of ionomer and ethylene vinyl acetate.

22. The films as claimed in claim 1, wherein the inner skin layers comprise low density polyethylene and wherein the exterior skin layer comprises a polymer or polymer blend selected from the group consisting of: ionomer and a blend of ethylene vinyl acetate and metallocene catalyzed polyethylene.

23. The films as claimed in claim 1, wherein the inner skin layers comprise a blend of linear low density polyethylene and low density polyethylene

24. The films as claimed in claim 1, wherein the films further comprise at least one core layer.

25. The films as claimed in claim 20, wherein the core layer comprises a polymer selected from the group consisting of: ethylene vinyl alcohol copolymer; polypropylene homopolymer; polypropylene copolymer; high density polyethylene; medium density polyethylene; polyamide; polyester; polyvinylidene chloride; and liquid crystalline polymer.

26. The films as claimed in claim 1, wherein the peelable seal can be pulled apart with the application of force of less than about three pounds per linear inch.

27. A foldover squeeze package used to contain flowable materials such as condiments, comprising:

a first film sidewall with at least one film layer, including an inner skin layer that forms an interior surface of the package,

a second film sidewall with at least two layers, including an inner skin layer that forms an interior surface of the squeeze package and an exterior skin layer that forms an exterior surface of the squeeze package,

wherein the inner skin layer of the second film sidewall is capable of sealing at its surface to the inner skin layer of the first film sidewall at a first sealing temperature to form a perimeter of a squeeze package,

wherein the exterior skin layer of the second film sidewall contains a heat activated resin and is capable of sealing to itself in a peelable seal at a second sealing temperature below the first sealing temperature without affecting the integrity of the seal between the first and second film sidewalls,

wherein the exterior skin layer, when sealed to itself at a second temperature, forms a peelable seal that is sufficiently weak to be peeled apart manually and that is sufficiently strong to remain sealed during storage and until ready for use,

wherein the inner skin layers of first and second film sidewalls are adhered to each other along the perimeter of the package, and

wherein the second sidewall defines an outlet adapted to permit flowable material to exit the package in a controlled fashion;

wherein a flap of the package is folded over and sealed to itself in a peelable seal around the outlet, wherein the peelable seal is located between the exterior skin layer of the second sidewall and itself.

28. The foldover squeeze package as recited in claim 27, wherein the outlet comprises a tab defined by a score line that is adapted to be torn away from the second sidewall to open the package when the flap is pulled open.

29. The foldover squeeze package as recited in claim 27 wherein the outlet is an opening cut in the second sidewall.

30. The foldover squeeze package as recited in claim 27, wherein the heat activated resin comprises at least one polymer selected from the group consisting of: ionomer; polypropylene; ethylene/alpha olefin; ethylene vinyl acetate; ethylene methylacrylate copolymer; polyethylene; ethylene methyl acrylic acid and blends thereof.

31. The foldover squeeze package as recited in claim 27 wherein the exterior skin layer of the second film contains a weakening agent.

32. The foldover squeeze package as recited in claim 31, wherein the weakening agent is selected from the group consisting of ionomer blended with polyethylene; ionomer with ethylene vinyl acetate; ionomer blended with ethylene methylacrylate; polypropylene blended with polyethylene; talc; mica; and silica.

33. The foldover squeeze package as recited in claim 31, wherein the weakening agent is polybutene.

34. The foldover squeeze package as recited in claim 27, wherein the second sealing temperature is at least about 20° F. below the first sealing temperature.

35. The foldover squeeze package as recited in claim 27, wherein the peelable seal can be pulled apart with the application of force of less than about three pounds per linear inch.

36. The foldover squeeze package as recited in claim 27, wherein the inner skin layer the first film sidewall has same composition as the inner skin layer of the second film sidewall.

37. A method of forming a foldover squeeze package used to contain flowable materials such as condiments, the method comprising:

providing a first film with a first surface adapted for use as an interior surface of a first sidewall of a squeeze package,

providing a second film with a first surface adapted for use as an interior surface of a second sidewall of a squeeze package, the second film having at least two layers, wherein the first layer is adapted for use an interior surface of a second sidewall of a squeeze package and the second layer is adapted for use as an exterior surface of a second sidewall of a squeeze package,

forming an outlet in the second film, wherein the outlet is adapted to allow the flowable material to exit the squeeze package,

sealing the first surfaces of the first and second films together to define the perimeter of the package at a first sealing temperature,

forming a peelable seal between opposing portions of the second film around the outlet by folding a flap of the package over the outlet and sealing the flap of the package over the outlet and applying heat at a second sealing temperature below the first temperature,

wherein the peelable seal is sufficiently weak to be peeled apart manually to expose the outlet and is sufficiently strong to remain sealed during storage and until ready for use.

38. The method as recited in claim 37, wherein the second sealing temperature is at least about 20° F. below the first sealing temperature.

39. The method as recited in claim 37, wherein the peelable seal can be pulled apart with the application of force of less than about three pounds per linear inch.