Patent Description:
The present invention relates to containers having a flexible liner disposed within the interior of the container and a membrane valve disposed on a flexible membrane which closes the container.

Food and drink products and other perishable items are often packaged in sealed composite containers. In some cases, these may be rigid or semi-rigid paper containers such as those are often used to store foodstuffs such as, but not limited to, potato chips, peanuts, candies, cookies, wafers, and/or crackers. In some embodiments, the container may be cylindrical. The bottom end of the container may comprise a sealed paper bottom and the top end of the container may be sealed with a flexible membrane.

When a container is sealed, its internal pressure will be equal that the external atmospheric pressure. However, the container internal pressure and the external atmospheric pressure may vary during, for example, shipping to higher or lower altitude locations. As altitude increases, atmospheric pressure decreases, and vice versa. For example, at an altitude of <NUM> feet, atmospheric pressure is approximately <NUM> PSI. However, at an altitude of <NUM> feet, atmospheric pressure is approximately <NUM> PSI. Thus, transportation of a sealed container to a lower altitude may result in negative pressure (lower internal pressure than external pressure) and transportation of a sealed container to a higher altitude may result in positive pressure (higher internal pressure than external pressure).

In containers, positive pressure may cause bulging, failed heat seals, exploded/distended container sidewalls, or extended/distended paper bottoms. Negative pressure (vacuum effect) may cause internal distortion, failed heat seals, imploded container sidewalls, or imploded paper bottoms.

<CIT> discloses a composite container for vacuum packaging of products having a generally tubular body portion having opposite ends and an inner surface. A liner is attached to the body portion for receiving the products inside the liner and the body portion of the container. The liner has a memory and is able to move between a position adjacent the body portion to a position about the products placed therein when a vacuum is applied to the products. When the vacuum is removed from the products, the liner automatically returns from the position about the products to the position adjacent the body portion so that the products can be easily removed.

<CIT> discloses a composite container for vacuum packaging of products which utilizes a loose liner system that can constrict and move away from the body portion of the container when a vacuum is formed on the product packaged in the container to prevent distortion of the shape of the container.

<CIT> and <CIT> disclose systems with integrated one-way valves.

The present invention provides a container which minimizes and, in some cases, avoids package distortion due to internal and/or external pressure changes.

The present invention relates to containers having a flexible liner disposed within the interior of the container and a membrane valve disposed on a flexible membrane which closes the container. Aspects of the invention are in accordance with the appended independent claims. Various optional features are in accordance with the appended dependent claims.

There is described herein a container comprising: a base; at least one sidewall extending upwardly from the base and terminating in a top edge, wherein the at least one sidewall is paper-based; a removable flexible membrane adhered to the top edge, wherein the membrane comprises a one-way valve; and a liner ply at least partially adhered to an interior surface of the sidewall, wherein the liner ply is configured to at least partially release from the sidewall upon a pressure differential between the pressure within the container and the external pressure.

In an embodiment, the container sidewall comprises a composite material. In an embodiment, the container is rigid. In an embodiment, the container comprises spiral-wound paperboard. In an embodiment, the liner ply comprises a polymeric material. In an embodiment, the liner ply has barrier properties. In an embodiment, the adhesive comprises a dextrin-based adhesive. In an embodiment, the adhesive is flood coated between the liner ply and the sidewall. In an embodiment, the adhesive comprises a resealable adhesive.

There is described herein a container comprising: a base; at least one sidewall extending upwardly from the base and terminating in a top edge, wherein the at least one sidewall is paper-based; a removable flexible membrane adhered to the top edge, wherein the membrane comprises a one-way valve; and a liner ply pattern adhered to an interior surface of the sidewall, wherein the liner ply is configured to flex, in the unadhered areas, toward and away from the sidewall upon a pressure differential between the pressure within the container and the external pressure.

In an embodiment, the adhesive pattern comprises diagonal adhesive strips. In an embodiment, the container comprises spiral-wound paperboard and the diagonal adhesive strips follow the spiral-wound pattern. In an embodiment, the adhesive comprises a polyvinyl acetate-based adhesive. In an embodiment, the valve is integrally formed with the top membrane. In an embodiment, the valve is externally applied to the top membrane.

While some of the objects and advantages of the present invention have been stated, others will appear as the description proceeds when taken in conjunction with the accompanying drawings, which are not necessarily drawn to scale, wherein:.

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. Terms of reference such as "top," "bottom," or "side" are used to facilitate an understanding of the present invention in view of the accompanying figures. The identified reference terms or other similar terms are not intended to be limiting, and one of ordinary skill in the art will recognize that the present invention may be practiced in a variety of spatial orientations without departing from the spirit and scope of the invention.

Turning to the figures, a container <NUM> is illustrated. Although illustrated as a tube having a circular cross section, the body of the container <NUM> may have any cross-sectional shape known in the art. For example, the container <NUM> may have the general configuration of a rectangle or square, optionally with rounded corners. Likewise, the cross-section of the container may be generally triangular or have a higher order polygonal profile or irregular shape. The container may have an elliptical or ovular general shape in other embodiments. In an embodiment, the container is configured to stand stably upright on a surface.

The container <NUM> includes at least one vertical body wall which may be considered the sidewall <NUM>. The container <NUM> may also comprise a bottom wall <NUM>. In an embodiment, the container <NUM> is cylindrical or tubular. In this embodiment, the bottom wall <NUM> may be generally circular. In another embodiment, the container <NUM> may comprise multiple vertical body walls, such as four body walls, which may each be considered side walls or may be considered a front wall, a back wall, and two side walls. In this embodiment, the bottom wall may be generally square or rectangular. In an embodiment, the at least one sidewall <NUM> extends upwardly from the bottom wall <NUM>. In an embodiment, the container <NUM> is rigid, semi-rigid, or substantially inflexible.

The at least one sidewall <NUM> of the container may be composed of spiral-wound paperboard, cardboard, or any other paper-based product, in an embodiment. In another embodiment, the sidewall <NUM> may comprise another type of material, such as a molded plastic. Any material known in the art may be used in this embodiment. In an embodiment, the container sidewall <NUM> may include a barrier layer that serves as a barrier to the passage of liquids and/or gasses such as oxygen.

In an embodiment, the sidewall <NUM> has an inner surface <NUM> which extends around an open interior <NUM> of the container. The container sidewall <NUM> also has an outer surface <NUM> which forms the exterior of the container. The open interior <NUM> houses products, such as food products <NUM>, in an embodiment. While the container is well-suited for containment of food products, it should be understood that the container can be utilized for any product that would benefit from a hermetic seal. The container is particularly well-suited for any hermetically sealed container which will be exposed to or may experience changes in atmospheric pressure.

In an embodiment, the container sidewall <NUM> comprises a single ply which may be a body ply <NUM>, optionally composed of spiral-wound paperboard having a thickness of about <NUM>-<NUM> inch. In another embodiment, the container sidewall <NUM> is multi-ply.

In one embodiment, a label ply <NUM> may be adhered to the outer surface of body ply <NUM>. The label ply <NUM> may be constructed from any material known in the art, such as kraft paper, optionally in combination with various polymers or the like. In another embodiment, the label ply <NUM> may comprise a polymeric film. In certain embodiments, the label ply <NUM> may be multi-layered or may be metalized. The label ply <NUM> may be inkjet printed and may convey graphics, product information, nutritional information, instructions, and/or regulatory compliance information. In other embodiments, any printed information may be integral with the body ply <NUM> and/or printed directly thereon.

In an embodiment, the container <NUM> comprises a liner ply <NUM> at least partially adhered to the interior surface of the body ply <NUM>. In an embodiment, an adhesive layer <NUM> is disposed between the liner ply <NUM> and the body ply <NUM>.

The liner ply <NUM> may comprise a polymeric material or any other material known in the art. In an embodiment, the liner ply <NUM> comprises a polyethylene film. The liner ply <NUM> may be flexible, resilient, stretchable, and/or airtight. The liner ply <NUM> may be impermeable to liquids and gases. The liner ply <NUM> may be single ply or constructed of multiple layers (multi-ply). The liner ply <NUM> may comprise layers of kraft paper, a polymeric material, and a foil layer, or any combination thereof, in an embodiment. The liner ply <NUM> may have barrier properties.

In an embodiment, the liner ply <NUM> is adhered to the body ply <NUM> using an adhesive layer <NUM>. The adhesive layer <NUM> may, in an embodiment, be a releasable adhesive. The adhesive layer <NUM>, in an embodiment, is flood coated over the surface of the liner ply <NUM> and/or the body ply <NUM>. In this embodiment, the adhesive may have <NUM>% coverage or nearly <NUM>% coverage between the liner ply <NUM> and the body ply <NUM>. In this embodiment, the adhesive layer <NUM> may comprise a weak adhesive, such as a corn starch-based or dextrin-based adhesive, a pressure-sensitive adhesive, or any other adhesive that has a limited adhesion. In an embodiment, the adhesive layer <NUM> may comprise a cohesive. In this embodiment, the weak adhesive may allow the liner ply <NUM> to at least partially separate from the body ply <NUM> upon a pressure differential between the pressure within the container and the external pressure (i.e. a movement from a higher elevation to a lower elevation, causing negative pressure).

In an embodiment, the adhesive maintains its adhesion along the sidewall <NUM> nearest the container ends. For example, the liner ply <NUM> may continuously remain adhered to the sidewall <NUM> nearest the top end (optionally, on or near rolled edge <NUM>) and bottom end <NUM> of the cylindrical container, regardless of internal and external pressures. In an embodiment, the liner ply <NUM> is rolled into the rolled edge <NUM> and/or the seam at the bottom end <NUM> of the cylindrical container.

In an embodiment, a substantial portion of the liner ply <NUM> may separate from the body ply <NUM> upon a pressure differential between the pressure within the container and the external pressure. In another embodiment, at least <NUM>% of the liner ply <NUM> may separate from the body ply <NUM> upon a pressure differential between the pressure within the container and the external pressure. In yet another embodiment, at least <NUM>% of the liner ply <NUM> may separate from the body ply <NUM> upon a pressure differential between the pressure within the container and the external pressure. In an embodiment, the separation between the liner ply <NUM> and the body ply <NUM> occurs primarily near the midsection of the container body, between the top and bottom ends.

In an embodiment, the adhesive is a resealable adhesive, such as a pressure sensitive adhesive, which allows the liner ply <NUM> to at least partially re-adhere to the body ply <NUM> upon a pressure differential between the container <NUM> internal and external pressures (i.e. a movement from a lower elevation to a higher elevation, causing positive pressure). Thus, in this embodiment, the liner ply <NUM> may repeatedly release from and reseal to the body ply <NUM> as pressure differentials occur. In an embodiment, the inventive container is effective across a pressure differential of between about <NUM> inches mercury and about <NUM> inches mercury.

<FIG> shows a sectional view of an embodiment of the tubular container <NUM> wherein the liner ply <NUM> is substantially released from the body ply <NUM>. More specifically, the axially opposed end portions of the liner ply <NUM> (near the top end and bottom end of the container) remain adhered to the inner surface of the body ply <NUM>, but are separated by a medial portion <NUM> of the liner ply <NUM> disposed between the axially opposed end portions that is free and un-adhered to the body ply <NUM>. Accordingly, after the food products <NUM> have been placed inside the cavity defined by the liner ply <NUM>, the liner ply <NUM> is free to move inwardly against the food products <NUM> when a vacuum is created, balancing the pressure on the inner and outer surfaces of the liner ply <NUM>. Likewise, the liner ply <NUM> may move outwardly away from the food products <NUM> when internal pressure increases.

In another example, the adhesive layer <NUM> may be pattern applied to either the liner ply <NUM> or the body ply <NUM> interior surface prior to application of the liner ply <NUM> to the body ply <NUM>. In this embodiment, the pattern of the adhesive <NUM> between the liner ply <NUM> and the body ply <NUM> may comprise one or more adhesive-free regions <NUM> (shown in <FIG>). In an embodiment, the pattern of the adhesive layer <NUM> may be repetitive, such as a plaid, horizontal, vertical or diagonal stripes, a repeating diamond, a criss-cross, or a cross-hatched pattern. In an embodiment, the pattern may comprise diagonal lines which follow the spiral patter of a spirally-wound container. Some exemplary patterns are set forth in <FIG>, but the invention should not be limited to these patterns. Any pattern known in the art may be utilized. In some embodiments, the adhesive pattern between the liner ply <NUM> and body ply <NUM> is asymmetrical.

In the pattern adhesive embodiments, the adhesive utilized may comprise a stronger adhesive than would be used in the <NUM>% coverage embodiment. An example of a stronger adhesive which could be used in this embodiment is a polyvinyl acetate (PVA)-based adhesive such as PVAc white glue, or any other adhesive known in the art. In this embodiment, the liner ply <NUM> may at least partially separate from the body ply <NUM> only in the adhesive-free regions <NUM>, upon a pressure differential between the container <NUM> internal and external pressures. In this embodiment, the stronger adhesive may retain adhesion between the liner ply <NUM> and the body ply <NUM> in the areas where the adhesive is pattern applied, regardless of external or internal pressure differentials. That being said, the adhesive utilized in the pattern adhesive embodiments could comprise a weaker adhesive such as a dextrin-based adhesive.

<FIG> shows a sectional view of the tubular container <NUM> wherein the liner ply <NUM> is sealed with a pattern adhesive layer <NUM> and is released or substantially released from the body ply <NUM> in only the adhesive-free regions <NUM>. In an embodiment, in addition to maintaining adhesion in the patterned adhesive regions <NUM>, the liner ply <NUM> may remain adhered to the body ply <NUM> near the top end and bottom end of the container, as was described above. More specifically, the axially opposed end portions of the liner ply <NUM> remain adhered to the inner surface of the body ply <NUM>, but are separated by a medial portion <NUM> of the liner ply <NUM> disposed between the axially opposed end portions that is free and un-adhered to the body ply <NUM> in the adhesive-free regions <NUM>. Accordingly, after the food products <NUM> have been placed inside the cavity defined by the liner ply <NUM>, the portions of the liner ply <NUM> which are in the adhesive-free regions <NUM> are free to move inwardly against the food products <NUM> when a vacuum is created, balancing the pressure on the inner and outer surfaces of the liner ply <NUM>.

In either embodiment, if the container <NUM> is transported from a higher altitude to a lower altitude, the internal pressure within the container <NUM> may be less than atmospheric pressure, creating a vacuum on the interior of the can (negative pressure). The liner ply <NUM> may then at least partially detach or separate from the body ply <NUM>, or move inwardly toward the food product <NUM>, to adjust the internal volume of the container <NUM>. The stress of the internal vacuum is alleviated by the reduction in volume from the liner ply <NUM> shape change, reducing or eliminating container implosion.

Similarly, in another example, relatively hot potato chips (crisps) could be deposited within the container <NUM> and then sealed by an end closure <NUM>. Hot air may become trapped within the container <NUM>. As the temperature of the air in the container <NUM> decreases, the volume of the air decreases as well. Thus, a slight vacuum or negative pressure may form within the container. The vacuum on the interior of the container <NUM> may introduce excessive stress to the body ply <NUM> of the container <NUM>, which may result in at least partial inward bending or collapsing of the container sidewall <NUM> along the length of the container. This can result in an unacceptable appearance for the container <NUM> or an unacceptable sealing of the product <NUM> within the container <NUM> (i.e. the heat seal on one or both ends may fail or partially fail). In this scenario, the liner ply <NUM> may at least partially detach or separate from the body ply <NUM>, or move inwardly toward the food products <NUM>, to adjust the internal volume of the container <NUM>. The stress of the internal vacuum is alleviated by the reduction in volume from the liner ply <NUM> shape change, reducing or eliminating container distortion, implosion and/or collapse.

In one embodiment, the liner ply <NUM> is adhered only to the sidewall <NUM> of the container <NUM>. In another embodiment, the liner ply is adhered to the sidewall <NUM> and the bottom wall <NUM> of the container <NUM>. In this embodiment, the liner ply <NUM> may have a bottom surface. The liner ply <NUM> may also have at least one sidewall extending upwardly from the optionally bottom surface and may comprise a flexible open-ended bag. In other embodiments, the liner ply <NUM> is tubular in nature, optionally extending onto the bottom wall <NUM> without having a bottom surface. Any liner ply <NUM> configuration known in the art may be useful in the invention. In an embodiment, the shape and configuration of the liner ply <NUM> is substantially similar to or the same as the shape and configuration of the container <NUM>. For example, if the container <NUM> is cylindrical, the liner ply <NUM> may also be substantially cylindrical or cylindrical. The liner ply <NUM> may have a shape and size that permit it to be disposed in the interior of the container <NUM> with which it is to be used.

In one embodiment, the container sidewall <NUM> is open on its top end and the sidewall <NUM> terminates in a top edge <NUM> which defines the open top end <NUM>. The top edge <NUM> may be a rolled edge or bead. In an embodiment, the liner ply <NUM> extends the entire length of the body ply <NUM>, including over and across the top edge <NUM>. In an embodiment, the liner ply <NUM> may be rolled into the construction of the bead. In this embodiment, the membrane lid <NUM>, discussed below, may attach to the liner ply <NUM> over the top edge <NUM>. In another embodiment, the liner ply <NUM> does not extend over the top edge <NUM> and may terminate just before the top edge <NUM>. In an embodiment, the liner ply <NUM> extends through the curl and/or seam, affixing the bottom end wall to the container sidewall. In an embodiment, the extension of the liner ply <NUM> through the top edge <NUM> and/or bottom edge of the container aids in ensuring the adhesion of the liner ply <NUM> to the body ply <NUM>.

In an embodiment, a food product <NUM> is stacked or stored within the container <NUM>. In an embodiment, the food product <NUM> does not directly contact the inner surface <NUM> of the container sidewall <NUM> due to the interference of the liner ply <NUM>. Byproducts from the food product (i.e. oil, grease) are thus prevented from contact with or migration into the container body ply <NUM>. In this way, the body ply <NUM> can be easily recycled if the liner ply <NUM> is removed from its interior. Likewise, liner ply <NUM> can also be recycled.

In a particular embodiment, use of the liner ply <NUM> may avoid the need for a barrier film or barrier layer to be applied to the interior surface <NUM> of the container body or incorporated into the body ply <NUM>, thereby reducing costs, manufacturing time, and improving the recyclability of the container.

In one embodiment, the tubular container <NUM> of the present invention includes a top end closure <NUM> and a bottom end closure <NUM>. In an embodiment, the top end of the container <NUM> may be closed via a flexible membrane <NUM> that is affixed or sealed to the top edge <NUM> of the tubular container <NUM>. The flexible membrane <NUM> may be made of a single ply or multiple plies of flexible laminate film(s), kraft paper, foil, polymers, and/or any other materials known in the art. In an embodiment, the flexible membrane <NUM> may be heat sealed or adhesively attached to the top end of the tubular container <NUM>. In an embodiment, the membrane <NUM> includes a barrier layer that serves as a barrier to the passage of liquids and/or gasses such as oxygen. The flexible membrane <NUM> may be peelably removable from the container <NUM> in order to access to contents thereof.

In an embodiment, a one-way valve <NUM> is disposed within the membrane <NUM>. In an embodiment, the valve <NUM> can be externally applied to the top membrane <NUM> after formation of the membrane or, in another embodiment, the valve <NUM> may be integrally formed with the top membrane <NUM>. In the external application of a valve <NUM>, a slit may be cut into the top membrane <NUM> and the valve <NUM> may be adhered over the slit. The externally-applied valve <NUM> may have a pressure sensitive (or other) adhesive disposed on its lower side and a release paper may be removed before using the PSA to adhere the valve <NUM> to the membrane. The valve may otherwise operate as is set forth herein.

In either embodiment, the valve <NUM> is in communication with the interior <NUM> of the container, within the interior of the liner ply <NUM>. More specifically, the valve <NUM> is disposed such that the open interior of the container may release gases through the valve and to the atmosphere. In an embodiment, the valve <NUM> is located in the center of the membrane <NUM>. In an embodiment, the valve <NUM> may be located internal of the perimeter of the liner ply <NUM>.

<FIG> shows a top view of the membrane <NUM> and valve <NUM> and <FIG> show an exploded cross-sectional view of the membrane <NUM> and the valve <NUM>, in various configurations and embodiments. Membrane structure <NUM> may comprise a first film layer <NUM> and a second film layer <NUM>. The second film layer <NUM> may be laminated to the first film layer via a permanent adhesive <NUM> which may, in an embodiment, be pattern-applied to at least one of the first <NUM> or second <NUM> film layers. In another embodiment, the permanent adhesive may be flood-coated over one or more of the layers and then deadened to create an area which is not adhered.

The first film layer <NUM> may form the outer layer of the membrane <NUM>, whereas the second film layer <NUM> may form the inner layer of the membrane <NUM>, and is thus underneath the first film layer <NUM>. The first film layer <NUM> may include a first cut line <NUM>, and the second film layer <NUM> may include a second cut line <NUM>, which is offset from the first cut line <NUM> (e.g., is spaced apart from the first cut line). While the cut lines <NUM>, <NUM> are shown in the figures as straight lines, it should be understood that the cut lines can have any shape or configuration known in the art. For example, the cut lines <NUM>, <NUM> may be curved, v-shaped, or u-shaped. The cut lines <NUM>, <NUM> may be semi-circular, in an embodiment. In an embodiment, the cut lines are aligned vertically or horizontally. In an embodiment, the cut lines are symmetrical. In other embodiments, the bottom cut line (on the layer closest to the interior of the container <NUM>) is larger than the top cut line.

A cross-section of an embodiment of the valve <NUM> is shown in <FIG>, in a closed position, and in <FIG>, in an open position. With reference to <FIG>, the valve <NUM> includes the first and second cut lines <NUM>, <NUM>, such that the first and second cut lines are contained within a perimeter <NUM> of the valve <NUM> (shown in <FIG>). The valve <NUM> may, for example be an area of the membrane <NUM> that is devoid of the permanent adhesive <NUM> adhering the first and second film layers <NUM>, <NUM> to each other. In this way, the perimeter <NUM> of the valve <NUM> may be the interface between an area including permanent adhesive <NUM> and an area devoid of permanent adhesive. The perimeter <NUM> of the valve <NUM> is illustrated as a rectangular shape, but it should be understood that the valve <NUM> can be any shape known in the art. For example, the perimeter of the valve can be triangular, circular, ovular, or any other shape known in the art.

The valve <NUM> may, in an embodiment, comprise a viscous medium, such as oil <NUM>, that is pattern-applied to at least one of the first or second film layers <NUM>, <NUM> and is disposed between the first and second film layers so as to occupy at least a portion of the valve area. The oil <NUM> may, for example, be silicone oil in some cases. The presence of the oil <NUM> may encourage the opposing surfaces of the first and second film layers <NUM>, <NUM> (e.g., the surface of each film layer that is adjacent to or most proximate the other film layer) to maintain contact with each other (with the oil disposed therebetween) by virtue of the viscosity and/or surface tension of the oil, such that the valve <NUM> is biased towards the closed position shown in <FIG> when the pressure inside the package is below a certain threshold pressure. For example, in some embodiments, the volume of oil <NUM> disposed between the first and second film layers <NUM>, <NUM> is selected such that the valve opens when the pressure inside the container <NUM> just exceeds the atmospheric pressure outside the package. An example of a desirable range of pressures inside the package for moving the first layer <NUM> towards the open position shown in <FIG> is approximately <NUM> psi to approximately <NUM> psi.

The valve <NUM> opens, as shown in <FIG>, when a gas begins to move from the interior of the container <NUM> through the second cut line <NUM>, as shown by the arrows. The gas pushes the first film layer <NUM> slightly upwardly, in some embodiments, and continues to travel through the valve area (through the oil <NUM>, if present) toward the first cut line <NUM>. The gas then passes through the first cut line <NUM>, shown by the arrow in <FIG>, and is dispelled into the atmosphere.

In addition, when the atmospheric pressure outside the package is slightly above the pressure inside the package, the valve <NUM> is configured to move from the open position shown in <FIG> to the closed position shown in <FIG>, so as to seal the valve <NUM> closed and prevent gas and/or moisture from entering the package. In some embodiments, the valve <NUM> is configured such that a desirable range of atmospheric pressures outside the package for moving the first layer <NUM> towards the closed position shown in <FIG> is approximately <NUM> psi to approximately <NUM> psi, but in any case is less than the pressure required inside the container <NUM> to open the valve <NUM>.

In some embodiments, an opposing surface of at least one of the first or second film layers <NUM>, <NUM> may further include a surface treatment <NUM> configured to decrease an amount of surface energy between the first and second film layers <NUM>, <NUM> in the valve area <NUM>. The surface energy may be characterized as the amount of energy required to adhere the opposing surfaces of the first and second film layers <NUM>, <NUM> to each other. Thus, while the addition of the oil <NUM> in the valve <NUM> between the opposing surfaces of the first and second film layers <NUM>, <NUM> serves to increase the surface energy of the interface between the opposing film surfaces, the resulting surface energy may be too great to allow the valve <NUM> to open (<FIG>) at the desired pressure level of the package interior. The inclusion of the surface treatment <NUM> for at least one of the opposing surfaces of the first and second film layers <NUM>, <NUM>, however, may counteract the increased adhesion force imparted by the oil <NUM>, thereby reducing the surface energy to a level that allows the valve to be moved from the closed configuration shown in <FIG> to the open configuration shown in <FIG> when a desired level of pressure is achieved within the package.

In some embodiments, for example, the surface treatment <NUM> may comprise at least one of a printed ink, a coating, or a texture that is applied to one or both of the opposing surfaces of the first and second film layers <NUM>, <NUM>. The surface treatment (e.g., the printed ink, coating, or texture) may serve to create bumps or ridges that extend from the surface of the respective film layer <NUM>, <NUM> that is treated toward the opposing surface of the other film layer. In the depicted example of <FIG>, for example, the surface treatment <NUM> has been applied to the inner surface of the first film layer <NUM>, such that the ridges extend from the first film layer <NUM> towards the second film layer <NUM>. Accordingly, the surface energy of the interface between the first and second film layers <NUM>, <NUM> may be decreased due to the reduced contact area between the two film layers. For example, instead of substantially the entire opposing surface of the first film layer <NUM> in the valve <NUM> contacting substantially the entire opposing surface of the second film layer <NUM> in the valve <NUM>, in which case the surface energy would be at a maximum, the ridges created by the surface treatment <NUM> in some embodiments may reduce the contact area to the sum of the areas over which each of the ridges contacts the corresponding locations of the opposing surface of the respective film layer. The type of surface treatment, the number of ridges created, and/or the amount of inherent separation between the first and second film layers <NUM>, <NUM> caused by the extension of the ridges may be selected to achieve a desired surface energy that results in the opening of the valve at the desired package pressure. In addition, the pattern of the ridges may be selected to further tune the opening and closure of the valve, depending on the requirements of the package. In some cases, the thickness of the surface treatment (e.g., thickness of the coating used), the roughness imparted by the surface treatment (e.g., based on the chemical makeup of the surface treatment), and the location of the surface treatment may also affect the resulting surface energy.

In the depicted embodiments of <FIG>, the surface treatment <NUM> of the first or second film layers is located only in the valve area <NUM>. However, in other embodiments, the surface treatment may extend outside the valve area <NUM>. For example, in some cases, the surface treatment may extend along the entire film, or the surface treatment may be applied to an area that is larger than the valve area <NUM>. In this way, alignment of the valve area with the location of the surface treatment during lamination of the film layers <NUM>, <NUM> may be easier to achieve, such as during the manufacturing process.

Likewise, in an embodiment, rather than utilizing a surface treatment, particles may be present within the valve structure, optionally within the oil <NUM>. The particles may create a separation between the first and second film layers <NUM>, <NUM> and/or decrease the surface energy of the interface between the first and second film layers <NUM>, <NUM>.

The flexible laminate structure may include first and second film layers <NUM>, <NUM> made of various different materials, depending on the particular application (e.g., depending on the type of product stored in the package). The first and/or second film layers <NUM>, <NUM> may, for example, include a polymer. In some embodiments, for example, one of the first or second film layers <NUM>, <NUM> may comprise polyethylene terephthalate (PET). In other embodiments, one of the first or second film layers <NUM>, <NUM> may include oriented polypropylene (OPP). Other materials that may be used for the first or second film layers <NUM>, <NUM> may include polyethylene (PE), metal foil (e.g., aluminum), metallized oriented polypropylene (mOPP), metallized polyethylene terephthalate (mPET), and copolymer polypropylene (CPP), to name a few. Accordingly, typical laminate structures may include, for example, PET/Foil/PE, PET/Foil/PET/PE, PET/mPET/PE, PET/mOPP/PE, OPP/mOPP/PE, PET/PE, OPP/PE, OPP/OPP, OPP, mOPP, PET/CPP, and PET/Foil/CPP.

In this regard, in some cases, the flexible laminate structure described above may be made using a first or second film layer <NUM>, <NUM> (or both) that includes two or more sub-layers, as shown in <FIG>. One or both of the first and second film layers <NUM>, <NUM> may, for example, be a <NUM>-ply film, a <NUM>-ply film, a <NUM>-ply film, or include additional plies, depending on the particular application (e.g., depending on the type of product to be stored in the package), with some example structures as noted above. In <FIG>, for example, a flexible laminate structure showing the integrated valve in a closed configuration is illustrated that has a single-ply first film layer <NUM> and a <NUM>-ply second film layer <NUM>. Sub-layers having different characteristics (e.g., different thicknesses, different materials, etc.) may be used in some cases to achieve certain oxygen and/or moisture transmission rates, so as to promote the freshness and/or shelf life of the product stored in the package. For example, the first film layer <NUM> may be a single-ply layer of PET, whereas the second film layer <NUM> may be a <NUM>-ply film with sub-layers of foil/PET/PE.

In an embodiment, if the container <NUM> is transported from a higher altitude to a lower altitude, the internal pressure within the container <NUM> may be greater than atmospheric pressure, creating greater pressure on the interior of the container <NUM> than is present outside the container <NUM> (positive pressure). The one-way valve may allow release of the interior pressure without compromising the hermetic seal of the container <NUM>, reducing or eliminating heat seal failures and outward container <NUM> or bottom end <NUM> distortion (i.e. distended sidewalls, bottom walls, etc.).

In an embodiment, a removable overcap <NUM> is disposed over the membrane seal <NUM>. In another embodiment, the top end closure comprises an overcap <NUM> without a flexible membrane. In an embodiment, the overcap <NUM> is configured to snap-fit onto the rolled rim <NUM> of the container sidewall <NUM>. The overcap may be made of paper, plastic, metal, foil, any combination thereof, or any other material(s) known in the art. The overcap <NUM> may comprise a barrier treatment and/or barrier layer. In an embodiment, the overcap <NUM> is configured to seal closed the opening <NUM> of the container <NUM> and/or enclose the interior of the container. In an embodiment, the overcap <NUM> is removable and replaceable. In an embodiment, the overcap <NUM> may be porous or breathable to allow for off gassing via the valve <NUM>. In another embodiment, the overcap <NUM> may have a larger inner dimension to provide space for released gas via the valve <NUM>.

Regardless of the shape of the container <NUM>, the overcap <NUM> is designed to snugly fit over the edge <NUM> of the container sidewall <NUM> to enclose the container contents. In an embodiment, if the container <NUM> is cylindrical, the overcap <NUM> is generally circular or disk-shaped and conforms to the dimensions of the container <NUM>.

The bottom end closure <NUM> of the tubular container <NUM> may be constructed of metal, paper, plastic, or any other material known in the art. The bottom end closure <NUM> may be heat sealed onto the container body.

In an embodiment, one or more tamper evidence features may be presented within the container structure. Many tamper evidence features are known in the art and are encompassed within the invention.

As an advantage to the invention, if/when a vacuum is created within the container <NUM> (negative pressure), the flexible nature of the liner ply <NUM> allows it to separate from the body ply <NUM> and move inwardly against the food products <NUM>, equalizing the pressure on the inside and outside of the container <NUM>. As the liner ply <NUM> moves inwardly, a space <NUM> may develop between the liner ply <NUM> and the body ply <NUM>. In an embodiment, the container sidewall <NUM> comprises a relatively porous paperboard construction, which allows for a sufficient migration of air to travel therethrough such that the space <NUM> between the liner ply <NUM> and the body ply <NUM> remains at atmospheric or ambient pressure. Thus, the container sidewall <NUM> is not subjected to negative pressure over an extended period, which could cause the container <NUM> to collapse.

In an embodiment, the container <NUM> of the invention is hermetically sealed, preventing the ingress or egress of gases, liquids, or other particles, until the container <NUM> is opened by a consumer. When the container <NUM> is opened by the consumer, such as by removing the flexible membrane <NUM>, any existing vacuum may be released and the liner ply <NUM> may withdraw at least partially from the food products <NUM> and toward the container sidewall. This withdrawal of the liner ply <NUM> may aid in removal of the food products <NUM> from the container <NUM>.

The container <NUM> of the present invention provides numerous advantages. The container <NUM> also provides a product which is fully recyclable. The liner ply <NUM> can be removed from the container <NUM> after use and can be recycled as a plastic. The container <NUM> can be recycled as paper. The overcap <NUM> can be recycled as paper or plastic, depending on its construction. The use of a barrier material or barrier layer within the container <NUM> can be eliminated due to the presence of the liner ply <NUM>, saving manufacturing time, costs, and resources. Further, the food product <NUM> contained within the inventive container <NUM> is better protected from breakage and damage due to the cushioning provided by the liner ply <NUM>. Still further, the container <NUM> is better adaptable to changes in atmospheric and/or processing conditions which alter pressure on the interior or exterior of the container <NUM>, as described herein. The inventive container <NUM> avoids or reduces implosion, heat seal failures and/or externally extended paper bottoms.

The container <NUM> of the present invention may be manufactured according to the following process. A continuous strip of paperboard body ply material <NUM> is advanced through an adhesive applicator which applies an adhesive to the inner surface of the body ply. The adhesive applicator can be a standard roller type applicator that applies adhesive to the entire inner surface of the body ply <NUM>, in one embodiment, or can be a pattern applicator, in another embodiment.

The body ply <NUM> and adhesive layer <NUM> applied thereto may then be passed underneath a heater which evaporates at least part of the water content of the adhesive to render the adhesive substantially tacky. After heating the adhesive layer <NUM> on the body ply <NUM>, the body ply <NUM> and the liner ply <NUM> are fed to a shaping mandrel from opposite directions. The body ply <NUM> is passed under a skive adhesive applicator which applies the skive adhesive to the beveled surface of the skived second edge of the body ply <NUM>. The surface of the liner ply <NUM> that contacts the body ply <NUM> may be subjected to a corona treatment station. The opposite surface of liner ply <NUM> may be coated with lubricant from a roller <NUM>, which allows the liner ply to slide smoothly during the winding operation. The body ply <NUM> and the liner ply <NUM> are then wrapped around the shaping mandrel from opposite sides of the mandrel. Each ply is first wrapped under the mandrel and then back over the top in a helical fashion with the liner ply <NUM> wound against the surface of the mandrel, forming a tube.

The tube is then advanced down the mandrel by a winding belt. Optionally, an outer label ply <NUM> is passed over an adhesive applicator and wrapped around the body ply <NUM>. The label ply <NUM> could alternatively be applied before the winding belt. At a cutting station, the continuous tube is cut into discrete lengths before being removed from the mandrel.

In an embodiment, the end closures are then attached to the ends of the tube. At least one of the ends of the container <NUM> is rolled outwardly to form a rim <NUM> which provides a suitable surface for affixing the membrane <NUM>. Another end closure, such as a paper closure, is attached to the other end of the container <NUM>. In another embodiment, the paper end closure is applied to one end of the container <NUM> prior to filling of the container with the food products <NUM>.

Methods of manufacturing a membrane <NUM> including an integrated one-way valve feature are also provided. According to embodiments of the methods, a first film layer <NUM> may be laminated to a second film layer <NUM> via a pattern-printed permanent adhesive <NUM> that is applied to at least one of the first or second film layers <NUM>, <NUM>, as described above. A first cut line <NUM> may be defined in the first film layer, and a second cut line <NUM> may be defined in the second film layer <NUM>, where the first and second cut lines are offset with respect to each other. The cut lines <NUM>, <NUM> may be defined in the flexible laminate after the first <NUM> and second <NUM> film layers have been laminated to each other, such as by using precision scoring techniques. Alternatively, a separately-formed valve <NUM> may be attached to the flexible laminate at a predefined location.

The first and/or second cut lines <NUM>, <NUM> may be made in various ways, such as via a laser. As an alternative to the use of lasers for scoring the laminate, the cut lines <NUM>, <NUM> can be formed in the laminate by mechanical scoring or cutting. For instance, a kiss roll and a backing roll may be used to form a nip through which the laminate is passed. The kiss roll may comprise a rotary cutting die defining a cutting edge that is configured to define the first and/or second cut lines <NUM>, <NUM>.

As the first and second film layers <NUM>, <NUM> are laminated to each other, an area of the laminate may be left devoid of the permanent adhesive (or deadened if adhesive has been applied) so as to define the valve area <NUM>. As described above, the first and second cut lines <NUM>, <NUM> are defined within the valve area, such that the valve area includes the first and second cut lines. In addition, oil <NUM> may be pattern-applied to at least one of the first or second film layers <NUM>, <NUM> in the area of the laminate devoid of the permanent adhesive. A surface treatment <NUM> may be effected, or particles may be disposed, with respect to at least one of the first or second film layers <NUM>, <NUM>, and the surface treatment or particles may be configured to decrease an amount of surface energy between the first and second film layers in the valve area, as described above.

In some cases, effecting a surface treatment <NUM> with respect to at least one of the first or second film layers <NUM>, <NUM> may comprise using at least one of a printed ink, a coating, or a texture, such as to form ridges or bumps between opposing surfaces of the first and second film layers. The surface treatment may be effected with respect to at least one of the first or second film layers <NUM>, <NUM> only in the valve area in some embodiments, whereas in other embodiments the surface treatment may extend outside of the valve area, such as in cases were the surface treatment is effected with respect to substantially the entire opposing surface of a respective film layer.

As described above, the first and second film layers <NUM>, <NUM> may comprise different materials, such as PET, OPP, or other polymer materials, as well as non-polymer material such as aluminum foil. Moreover, at least one of the first or second film layers <NUM>, <NUM> may comprise two or more sub-layers, such as in the example depicted in <FIG>.

After filling the container <NUM> with food products <NUM>, the formed membrane <NUM> may be applied to the end of the tubular body. Thus, the present invention provides a method of manufacturing a composite container <NUM> having an at least partially detachable liner <NUM> and one-way valve <NUM> that overcomes the disadvantages of conventional methods and containers.

The container <NUM> of the present invention is particularly advantageous for packaging food products <NUM> having an elevated temperature, which upon cooling naturally create a negative pressure inside the sealed container or food products <NUM>, regardless of whether that container will be transported from higher elevations to lower elevations or vice versa. The negative internal pressure can be alleviated due to the liner ply <NUM> construction.

The method of the present invention allows the liner ply <NUM> to partially or substantially release from the body ply <NUM> and move inwardly toward the food products to alleviate any negative pressure. The body ply <NUM> allows air to travel to the space created between the liner ply and the body ply, such that the pressures on each side of the liner ply <NUM> are balanced. The new container <NUM> is easy to manufacture, yet is capable of withstanding a rigid shape under changing atmospheric conditions and providing a hermetic seal to prevent air and moisture from contaminating the products contained therein.

Claim 1:
A container (<NUM>) comprising:
a base;
at least one sidewall (<NUM>) extending upwardly from the base and terminating in a top edge (<NUM>), wherein the at least one sidewall (<NUM>) is paper-based;
a removable flexible membrane (<NUM>) adhered to the top edge (<NUM>), wherein the membrane (<NUM>) comprises a one-way valve (<NUM>), the one-way valve (<NUM>) is in communication with the interior of the container (<NUM>) within the interior of the liner ply (<NUM>) and is configured such that the valve opens when the pressure inside the container exceeds the atmospheric pressure or is at other desired pressure level, thereby to release gases through the valve and to the atmosphere; and
a liner ply (<NUM>) at least partially adhered directly to an interior surface of the sidewall (<NUM>) with an adhesive, wherein the adhered liner ply (<NUM>) is configured to at least partially release from the sidewall (<NUM>) upon a pressure differential between a lower pressure within the container (<NUM>) and a higher external pressure.