One-way valve score design

In flexible package, a one-way valve may include a substrate forming a portion of the flexible package and having at least one inlet score, a top sheet having at least one outlet score and secured thereto by an adhesive to define a valve chamber in which the substrate and the top sheet are not permanently adhered to each other, and a liquid film within the valve chamber and adhering the top sheet to the substrate within the valve chamber until a pressure differential exists causing gases to pass through the one-way valve. The inlet scores and the outlet scores may be non-linear, or may be linear scores that are not parallel to each other to prevent the scores from collapsing on themselves and preventing gas flow when the package buckles.

BACKGROUND OF THE INVENTION

Field of the Invention

This disclosure relates to packaging for products that tend to release gasses after filling and sealing. More particularly, this disclosure relates to flexible one-way gas release valve integrated into a lamination and attached to a packaging wall or a peelable seal.

Description of the Related Art

It is common in the marketplace to package products, and in particular food products, in flexible packaging containers. The food product may be deposited into an unsealed portion of the package, and then the package is sealed to maintain the food product within the interior of the package and isolate the food product from the ambient atmosphere surrounding the flexible package. For some food products, it may be desirable to reduce the gas present in the package at the time the flexible package is sealed to reduce the exposure of the food product to oxygen and maintain its freshness until a consumer opens the package.

Some food products stored in flexible packaging in this way may continue to release gasses after the package is sealed. For example, fresh roasted coffee goes through an “off-gassing” period that lasts 3-10 hours after the roast during which gas pressure created inside the beans during the roast are slowly released as the gas permeates through the shells. If the coffee is packaged during the off-gassing period, the gas released by the beans will increase the pressure within the flexible packaging. The increased pressure can create a pressure differential with the ambient atmosphere surrounding the package that could cause the packaging material or the seals to burst and compromise the integrity of the flexible package and expose the food product, namely the coffee, to the ambient atmosphere.

To release the gases and alleviate the corresponding pressure buildup within the flexible packaging, one-way valves may be integrated into the packaging material. The packaging material may be a lamination that typically comprises a top layer and a bottom layer adhered together by an adhesive, except in the area of a valve chamber of the one-way valve. Usually, the one-way valves require a film or lubricant in the valve chamber to increase adhesion between the laminate layers, thereby preventing gas from entering or exiting the container until the pressure in the interior of the flexible packaging creates a sufficient pressure differential with the ambient atmosphere. When a minimum pressure differential is reached, the pressure from the interior overcomes the adhesiveness of the film or lubricant in the valve chamber to allow the gas to escape from the flexible packaging until the internal pressure is reduced and the pressure differential drops below the minimum required to open the one-way valve.

An example of such a one-way valve is disclosed in U.S. Pat. No. 7,527,840 issued to Zeik on May 5, 2009, entitled “Flexible Laminate Having an Integrated Pressure Release Valve” (hereinafter “the Zeik patent”). The Zeik patent discloses a one-way valve in which a first lamina has an inlet channel in fluid communication with an interior of a container, a second lamina has an outlet channel in fluid communication with the ambient atmosphere surrounding the container, and a liquid film separates the first and second lamina in a valve region. The liquid film prevents external air from entering the valve region while allowing gas within the container to escape through the valve region when a sufficient pressure differential exists between the interior and the exterior of the container.

BRIEF SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, a one-way valve for a flexible package is disclosed. The one-way valve may include a substrate forming a portion of the flexible package and having at least one inlet score, a top sheet having at least one outlet score, an adhesive disposed between the substrate and the top sheet and adhering the top sheet to the substrate. The substrate, the top sheet and the adhesive define a valve chamber in which the substrate and the top sheet are not permanently adhered to each other, and the at least one inlet score fluidly connects an interior of the flexible package to the valve chamber and the at least one outlet score fluidly connects the valve chamber to an ambient atmosphere surrounding the flexible package. The one-way valve may further include a liquid film occupying at least a portion of the valve chamber and adhering the top sheet to the substrate within the valve chamber to prevent gas within the flexible package from passing through the one-way valve when a pressure differential between an internal pressure of the flexible package and an ambient air pressure is less than a minimum gas release pressure differential. The at least one inlet score is not a single linear inlet score and is not a plurality of linear inlet scores that are parallel to each other, and the at least one outlet score is not a single linear outlet score and is not a plurality of linear outlet scores that are parallel to each other.

In another aspect of the present disclosure, a method of producing a one-way valve for a flexible package is disclosed. The method may include forming at least one inlet score on a substrate of the flexible package and forming at least one outlet score on a top sheet of the one-way valve, wherein the at least one inlet score is not a single linear inlet score and is not a plurality of linear inlet scores that are parallel to each other, and the at least one outlet score is not a single linear outlet score and is not a plurality of linear outlet scores that are parallel to each other. The method may further include applying an adhesive to a substrate outer surface of the substrate that defines a boundary around the at least one inlet score, wherein the substrate, the top sheet and the adhesive define a valve chamber in which the substrate and the top sheet are not permanently adhered to each other, and the at least one inlet score fluidly connects an interior of the flexible package to the valve chamber and the at least one outlet score fluidly connects the valve chamber to an ambient atmosphere surrounding the flexible package. The method may also include applying a liquid film to at least a portion of the substrate outer surface within the boundary defined by the adhesive to adhere the top sheet to the substrate within the valve chamber to prevent gas within the flexible package from passing through the one-way valve when a pressure differential between an internal pressure of the flexible package and an ambient air pressure is less than a minimum gas release pressure differential.

Additional aspects are defined by the claims of this patent.

DETAILED DESCRIPTION

FIG. 1illustrates an exemplary flexible package10that may contain a food product (not shown), such as roasted coffee. The flexible package10may be formed from a single layer or multi-layer polymeric sheet or laminate substrate12that is folded and sealed to isolate an interior of the flexible package10and the food product enclosed therein from an ambient atmosphere surrounding the flexible package10. The flexible package10may be partially formed and closed while leaving an opening at top edge14to allow the food product to be deposited into the flexible package10. After the food product is deposited, a seal16may be formed at the top edge14to segregate the interior of the flexible package10from the exterior. Of course, other methods and sequences for forming and closing the flexible package10and depositing the food product therein will be apparent to those skilled in the art and are contemplated by the inventor.

As discussed above, some food products such as roasted coffee may release gases after being sealed in the flexible package10such that an internal pressure within the flexible package10may increase over time. In order to release the gas and reduce the internal pressure before the substrate12, the seal16and/or other seals (not shown) of the flexible package rupture, the flexible package10is provided with a one-way valve18that may allow the gases to escape from the interior of the flexible package10while preventing air, and in particular oxygen, from the ambient atmosphere from entering the interior of the flexible package10. The one-way valve18may be formed by providing one or more inlet scores20through the substrate12, and affixing a top sheet22having one or more outlet scores24to a substrate outer surface26of the substrate12in a position that overlays the inlet scores20.

The cross-sectional view ofFIG. 2illustrates the one-way valve18of the flexible package10in greater detail. The top sheet22and a corresponding portion of the substrate12may combine to form a laminate28. As discussed above, the substrate12may be a single layer or multiple layers of laminated material. The substrate12may be formed from an organic polymer sheet material or materials such as polyolefin, polyamides, polyesters, polycarbonates, high density polyethylene (HDPE), polyvinyl chloride (PVC), ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVOH), polyvinylidene chloride (PVDC), and the like and combinations thereof. In addition to the organic polymer sheet(s), the substrate12may include a metallized polymer film such as metallized polyethylene terephthalate laminated on the interior of the substrate12and in direct contact with the food product enclosed therein. The top sheet22may similarly be formed from one or more layers of organic polymer sheets, with the polymer sheets being transparent in some implementations to allow product and packaging information to be printed on a top sheet inner surface30.

The top sheet22is adhered to the substrate outer surface26of the substrate12by an adhesive32such as a permanent adhesive that will maintain the top sheet22affixed to the substrate outer surface26within a range of pressure differentials to which the one-way valve18will be exposed based on the expected internal pressures and ambient pressures. The adhesive32defines a boundary around the inlet scores20and the outlet scores24, and the substrate outer surface26, the top sheet inner surface30and the adhesive32combine to define a the valve chamber34of the one-way valve18. The valve chamber34is an area in which the substrate outer surface26and the top sheet inner surface30are not permanently adhered to each other. Instead, a liquid film36occupies some or all of the valve chamber34between the substrate outer surface26and the top sheet inner surface30, and in particular the area between the inlet scores20and the outlet scores24. The liquid film36helps the top sheet22adhere to the substrate12in the region corresponding to the valve chamber34, and may be a lubricant that does not dry or harden over the useful life of the flexible package10. The liquid film36may be silicon oil, hydrocarbon oil, glycerin, polyhydric alcohol (polyol), water or other appropriate lubricant that may temporarily yield when a predetermined opening pressure differential exists between the interior pressure and the ambient pressure surrounding the flexible package10.

The inlet scores20may be formed in the substrate12by laser scoring, mechanical puncturing or other appropriate methods for forming channels through the substrate12that place a substrate inner surface38and the interior of the flexible package10in fluid communication with the substrate outer surface26and the valve chamber34. The outlet scores24may be formed in a similar manner in the top sheet22to place the top sheet inner surface30and the valve chamber34in fluid communication with a top sheet outer surface40and the ambient atmosphere surrounding the flexible package10. The inlet scores20through the substrate12and the outlet scores24through the top sheet22are preferably offset and not aligned in a direction orthogonal to a plane defined by the laminate28. The liquid film36occupies enough of the valve chamber34to prevent air from the ambient atmosphere surrounding the flexible package10from entering the flexible package10through the one-way valve18. The liquid film36also enhances the adhesiveness of the top sheet22to the substrate12in the area of the valve chamber34so that gas42emitted by the food product inside the container does not escape until the internal pressure creates a pressure differential with ambient air pressure that exceeds a minimum gas release pressure differential. Exceeding the minimum gas release pressure differential will cause the liquid film36to temporarily yield and release at least a portion of the gas42until the internal pressure is released and the pressure differential is below the minimum gas release pressure differential.

FIG. 3shows the one-way valve18when the minimum gas release pressure differential is exceeded and the gas42flows out of the flexible package10through the one-way valve18. The gas42released by the food product inside the flexible package10has achieved a pressure sufficient to overcome the ambient air pressure and the adhesiveness of liquid film36between the substrate12and the top sheet22to create one or more pressure relief channels through the liquid film36. The flow of the gas42through the pressure relief channels is indicated by the unnumbered arrows inFIG. 3. The gas42will continue to flow out of the one-way valve18until the internal pressure is reduced sufficiently to drop the pressure differential below the minimum gas release pressure differential. At that point, the liquid film36will re-adhere the top sheet22to the substrate12within the valve chamber34to prevent further release of the gas42from the flexible package10.

As long as the substrate12of the flexible package10is relatively flat as shown inFIGS. 2 and 3, the inlet scores20and the outlet scores24provide channels sufficiently large for the flow of gas42through the one-way valve18. However, due to the inherent nature of flexible packaging, the substrate12can flex, bend and buckle when forces are applied to the flexible package10. Such buckling is illustrated inFIG. 4. When the substrate12and the top sheet22buckle and deform in the area of the valve chamber34, the inlet scores20and the outlet scores24can close on themselves, similar to a door hinge. The dimensions of the scores20,24and other components are exaggerated for clarity of illustration, but the inlet scores20may be partially closed and the outlet scores24may be completely closed. This partial or complete closure of the scores20,24can limit or completely cut off the ability for the gas42to flow through the one-way valve18. Current integrated one-way valves use linear scores in the substrate12and/or the top sheet22, and multiple linear scores that are parallel to each other. With these configurations, it is possible for the flexible package10to buckle in a manner that substantially closes all the linear scores and prevents any gas42from passing through the one-way valve18.

In one-way valves18in accordance with the present disclosure, the inlet scores20are not formed as either a single linear inlet score or as a plurality of linear inlet scores that are aligned parallel to each other. Similarly, the outlet scores24are not a single linear outlet score or a plurality of parallel linear outlet scores. Instead, the inlet scores20and the outlet scores24are provided as individual scores that cannot close on themselves along the entire length of the scores. Alternatively or in addition, multiple scores may be provided such that not all of the scores can close on themselves at the same time. With these configurations in accordance with the present disclosure, flow paths for the gas42through the one-way valve18are maintained at all times.

FIG. 5illustrates the configurations of the inlet scores20and the outlet scores24of the one-way valve18in greater detail. By using a circular or arc-shaped non-linear shape, the scores20,24cannot close on themselves along their entire length. In the illustrated embodiment, four arc-shaped inlet scores20are provided in the substrate12in an inlet score circular pattern. Four arc-shaped outlet scores24are formed in the top sheet22in an outlet score circular pattern having a larger diameter than a diameter of the inlet score circular pattern. As shown, the inlet score circular pattern is rotated approximately 45° relative to the outlet score circular pattern, but the relative positions of the circular patterns may be varied as necessary to ensure the requisite amount of flow of gas42through the one-way valve18.

Those skilled in the art will understand that the circular patterns may be varied in other ways to achieve desired performance characteristics of the one-way valve18. In addition to the positioning, the radii of the scores20,24may be increased or decreased to vary the relative sizes of the circular patterns as necessary to dictate the minimum gas release pressure differential at which the one-way valve18will open and release the gas42. The arc-shaped scores20,24may be provided with other curved but noncircular shapes such as elliptical, parabolic or other more complex curvatures. Additionally, each circular pattern may include more or fewer than the four scores20,24is illustrated, but providing multiple scores20,24in each circular pattern can create redundancy in the one-way valve18that can more reliably ensure the flow paths are maintained for gas42as the flexible package10buckles in various ways during use.

Other variations in the numbers, geometries and relative orientations of the scores20,24are contemplated by the inventor. For example,FIG. 6illustrates an alternative embodiment of a one-way valve50having four linear inlet scores52arranged in an inlet score square pattern, and four linear outlet scores54arranged in an outlet score square pattern. The inlet score square pattern is smaller than the outlet score square pattern, and the square patterns are rotated approximately 45° with respect to each other. The linear scores52,54and the square patterns may have larger or smaller relative sizes as necessary, and the square patterns may have different relative orientations. By providing a plurality of linear scores52,54that are not parallel to each other, some of the linear scores52,54may close on themselves when the flexible package10buckles and deforms, while others of the linear scores52,54will deform in different ways that do not close the linear scores52,54and allow the gas42to flow through the one-way valve50.

The square patterns discussed above are one example of providing a plurality of nonparallel linear scores in a one-way valve to ensure flow of gas42through the valve.FIG. 7illustrates another alternative embodiment wherein a one-way valve60includes three linear inlet scores62arranged in an inlet score triangle pattern, and three linear outlet scores64arranged in an outlet score triangle pattern. The inlet score triangle pattern is smaller than the outlet score triangle pattern, and the triangle patterns are rotated approximately 60° with respect to each other. The linear scores62,64and the triangle patterns may have larger or smaller relative sizes as necessary, and the triangle patterns may have different relative orientations. The linear scores62,64will respond to deformations and buckling of the flexible package10in a similar way as the linear scores52,54described above where some may collapse and close while others remain open to provide flow passages for the gas42. In further alternative embodiments, more or fewer linear scores may be provided in the one-way valves50,60and arranged in other geometric patterns that will ensure constant flow through the one-way valve.

FIGS. 8 and 9provide examples of one-way valves having non-linear scores that will not close along their entire length when the flexible package10is deformed.FIG. 8illustrates a one-way valve70having zigzag-shaped inlet scores72formed in the substrate12and zigzag-shaped outlet scores74formed in the top sheet22. The zigzag-shaped scores72,74are formed by series of linear segments that are not parallel to each other such that portion of the zigzag-shaped scores72,74may collapse and close when the flexible package10buckles while other portions of the zigzag-shaped scores72,74will remain open for gas flow.

InFIG. 9, a one-way valve80includes serpentine-shaped inlet scores82formed in the substrate12and serpentine-shaped outlet scores84formed in the top sheet22. The changes in direction in the serpentine-shaped scores82,84ensure that portions of the serpentine-shaped scores82,84will be open when the flexible package10deforms and buckles in a similar manner as the segments in the zigzag-shaped scores72,74having different orientations.

INDUSTRIAL APPLICABILITY

The one-way valves18,50,60,70,80in accordance with the present disclosure may serve to protect the flexible package10from over pressurization in the interior by ensuring continuous paths for the flow of gas42from the interior of the flexible package10to the ambient atmosphere surrounding the flexible package10. The illustrated embodiments are exemplary only, and other variations are contemplated where the substrate12and the top sheet22do not have either a single linear score or a plurality of linear scores that are arranged parallel to each other. For example, the inlet scores and the outlet scores of the one-way valves do not have to be of similar geometries or configurations such as matching circular, square or triangular shapes. Consequently, the inlet scores may be serpentine-shaped and the outer scores may be arc-shaped and arranged in a circular pattern in a particular implementation of a one-way valve. Other combinations of variations are contemplated so long as the necessary operation of the one-way valve is achieved when the flexible package buckles and deforms.

The flexible package10formed from the folded and sealed substrate12is exemplary of flexible containers in which one-way valves in accordance with the present disclosure may be implemented. The one-way valve may also be useful in rigid plastic or metal containers for food products such as coffee having a flexible peelable membrane seal adhered to a rim surrounding an open end of the container. Inlet scores in accordance with the present disclosure may be formed in the membrane seal that will act as a substrate. A top sheet having outlet scores in accordance with the present disclosure may be affixed to the membrane seal with an adhesive, and a liquid film may be deposited there between to form the one-way valve that will allow gas to escape from the container.