Patent Application
20240043189
The invention relates to packaging, and more particularly, to packaging of fresh produce.
Package designs for fresh produce face many challenges, because they must enable produce to remain alive and fresh within the package for as long as possible. In most cases, packaging that is tightly gas-sealed will suffocate the produce, and lead to its early demise and spoilage. For some types of produce that are whole or have a protective skin that retains moisture, such as apples and oranges, a “ventilated” packaging, may be the preferred option, whereby the atmosphere surrounding the produce is maintained close to ambient conditions, both in terms of O2 content and humidity.
With reference to
However, many packaging materials used for MAP packaging are substantially impermeable to moisture. With reference to
What is needed, therefore, is a fresh produce packaging solution that prevents high water vapor generating produce from being prematurely desiccated, while at the same time preventing any pooling of excess moisture within the package.
The present invention is a is fresh produce package that prevents high water vapor generating produce from being prematurely desiccated, while at the same time preventing pooling of excess moisture within the package.
The disclosed package includes a laminate polymer film that permits a limited exchange of moisture with the environment, while preventing gas exchange with the environment. This allows high water vapor generating produce, such as cucumbers and peppers, to establish a moisture-controlled environment (MCE) within the package that avoids desiccation of the produce, while at the same time allowing a sufficient water vapor transport to avoid pooling of excess moisture within the package. In some embodiments, the disclosed “MCE” packaging is formed entirely by the laminate film, thereby providing a flexible bag or pouch. In other embodiments, the laminate film is applied as a lidding film to a rigid or semi-rigid container or tray made from a material that is impermeable to both gases and water vapor.
The laminate polymer film of the present invention includes a first film layer, such as a polyethylene terephthalate (PET) film layer, that serves as a gas and moisture barrier (very low moisture vapor transport rate, “MVTR”). The first film is laminated to a second film layer, such as a nylon, polylactic acid (PLA) or cellulose, that also provides a gas barrier, but has a much higher MVTR than the PET layer. The high MVTR of the second film layer arises from a molecular attraction between the polymer and water molecules, which draws excess moisture into the polymer, and upon saturation thereof allows some of the moisture to escape into the ambient environment. Gases such as O2 and CO2 have low transmission rates through the second film layer, because they do not experience a similar molecular attraction to the polymer.
In embodiments, the first film layer has an MVTR (also referred to in the art as a “water” vapor transport rate, or “WVTR”) that is no greater than 2 g-mil/100 in2-day @ 100° F. and 90% relative humidity, while the second film layer has an MVTR that is greater than 10 g-mil/100 in2-day @ 100° F. and 90% relative humidity.
Gaps or openings are provided in the first film layer of the laminate film, thereby creating moisture transport windows (MTWs) that are covered by the second film layer but not by the first film layer. By controlling the number and sizes of these MTWs, the degree of moisture transport out of the package can be controlled, such that it is optimal for the intended contents. The laminate film can also include microperforations that penetrate through both of the film layers, thereby providing a limited O2 and CO2 gas exchange that creates a modified gaseous atmosphere within the package. These embodiments are referred to herein as Moisture Controlled Environment-Modified Atmosphere (MCE-MAP) packages.
Also disclosed herein is a method of manufacture of the disclosed MCE package. In some embodiments, the first and second film layers are adhesively laminated to each other. In some of these embodiments, the adhesive is sprayed onto one of the two layers through a mask that prevents the adhesive from being applied to designated window areas. In other of these embodiments, an adhesive-applying roller is used to apply the adhesive to one of the layers. The adhesive-applying roller includes insets that prevent the adhesive from being applied to the designated window areas. Once the adhesive has been applied, the two film layers are pressed together (laminated), for example by a pair of pressing or nip rollers.
In still other embodiments, a pressure and/or heat sensitive adhesive is applied uniformly to one of the film layers, after which the layers are pressed together by a pair of rollers that include corresponding inset and/or unheated regions that create window areas where the adhesive is not activated. In similar embodiments, the film layers are heat-sealed directly to each other by a pair of rollers that include unheated regions. As a result, the film layers are not bonded to each other in the regions that pass between the inset and/or unheated regions, thereby creating the required window areas. Under such circumstances, the adhesive used must not interfere with the moisture transfer rate of the second film layer.
After the two film layers have been laminated together, a device such as a laser or a die-cutting plate or roller is used to cut out and remove panels of the first film layer from within the window areas, while leaving the second film layer intact throughout the laminate film. In the case of a laser, the laser process conditions are adjusted such that it penetrates through the first film layer, but does not fully penetrate the second film layer. In the case of a die-cutting plate or roller, the die-cutting edges or blades extend above the surface of the plate or roller far enough to penetrate through the first film layer, but not far enough to penetrate completely through the second film layer. In embodiments, the window areas are slightly larger than the MTWs, thereby ensuring that no part of the cut panels is adhered to the second film layer.
The MCE package of the present invention is then created by cutting out a section of the laminate film in an appropriate size and shape, and bonding selected regions or “seams” of the laminate film to each other, and/or to an underlying rigid or semi-rigid container. In embodiments, the first film layer is made from a material such as PET that can be readily heat sealed, and the attachment of the “seams” of the laminate film is by heat sealing of the first film layer of the laminate film. In these embodiments, it is not necessary that the second film layer be readily heat sealable.
A first general aspect of the present invention is a laminate film suitable for incorporation in a moisture controlled fresh produce container. The laminate film includes a first film layer having a water vapor transport rate that is no greater than 3 g-mil/100 in2-day @ 100° F. and 90% relative humidity, a second film layer laminated to the first film layer, the second film layer having a water vapor transport rate that is greater than 10 g-mil/100 in2-day @ 100° F. and 90% relative humidity, and at least one moisture transport window (MTW), said MTW being a region of the laminate film that includes the second film layer, but does not include the first film layer.
In embodiments, the first film layer is a layer of heat-sealable polyethylene terephthalate (PET) film.
In any of the above embodiments, the second film layer can be a layer of nylon film. or the second film layer can be a cellulose or polylactic acid layer of film.
Any of the above embodiments can further include a plurality of microperforations suitable for establishing a modified gaseous atmosphere within the fresh produce container.
A second general aspect of the present invention is a fresh produce container that includes an interior surrounded by container walls, at least one of the container walls being at least partially formed by a laminate film according to any embodiment of the first general aspect.
In some embodiments, all of the container walls comprise the laminate film, while in other embodiments the laminate film is a lidding film applied to an underlying rigid or semi-rigid tray.
In any of the above embodiments, attachment of the laminate film so as to form the container can be by heat-sealing of the first film layer. In some of these embodiments the heat-sealing includes heat-sealing together of seam regions of the first film layer. And in any of these embodiments where the laminate film is a lidding film applied to an underlying rigid or semi-rigid tray, the heat-sealing can include heat-sealing of attachment regions of the first film layer to an upper rim of the underlying rigid or semi-rigid tray.
A third general aspect of the present invention is a method of making the laminate film of any embodiment of the first general aspect. The method includes providing a first film having a water vapor transport rate that is no greater than 3 g-mil/100 in2-day @ 100° F. and 90% relative humidity, providing a second film having a water vapor transport rate that is greater than 10 g-mil/100 in2-day @ 100° F. and 90% relative humidity, laminating the first film to the second film so as to create a laminated film comprising a first film layer of the first film and a second film layer of the second film, the first and second film layers being mutually attached to each other except within at least one window area of the laminated film, applying a cutting device to the laminated film, the cutting device being directed at the first film layer and configured to cut through the first film layer but not to cut completely through the second film layer, thereby forming a cut through the first film layer that defines and surrounds a removable panel of the first film layer that is entirely within the window area of the laminated film, and removing the removable panel from the laminated film, thereby forming a moisture transport window (MTW) within the window area that is covered by the second film layer, but within which the first film layer is absent.
In some of these embodiments, the attachment of the first film layer to the second film layer is by an adhesive. In some of these embodiments, the method includes applying the adhesive to an adhesive-applying roller having at least one inset, and applying the adhesive-applying roller to an adhesive-receiving film that is one of the first film and the second film before lamination together thereof, the adhesive not being applied to the adhesive-receiving film in gap areas that pass beneath the at least one inset, the at least one window area being formed in the gap areas during the subsequent adhesive lamination of the first film layer to the second film layer.
In other of these embodiments, the method includes positioning a mask above an adhesive-receiving film layer that is one of the first film layer and the second film layer before lamination together thereof, said mask including at least one blocked region through which access is to the underlying adhesive-receiving film layer is blocked, and spraying the adhesive through the mask and onto the adhesive-receiving film layer, the at least one window area being formed during the subsequent adhesive lamination of the first film layer to the second film layer in an area to which the adhesive was not applied to the adhesive-receiving layer because of the blocking region of the mask.
In still other of these embodiments, the adhesive is pressure and/or temperature activated, and does not interfere with a moisture transfer rate of the second film layer, and the method includes applying the adhesive uniformly to an adhesive-applied film layer that is one of the first film layer and the second film layer before lamination together thereof, aligning the first and second film layers with each other, and applying at least one of heat and pressure to the aligned first and second film layers by passing the aligned first and second film layers between a pair of laminating rollers that are configured to apply at least one of heat and pressure to the aligned first and second film layers, said laminating rollers having aligned deactivated regions that are configured not to apply the at least one of heat and pressure to the aligned first and second film layers, the at least one window area being formed during the lamination of the first film layer to the second film layer due to a failure to activate the adhesive in regions of the aligned first and second film layers to which the deactivated regions of the laminating rollers were applied.
In any of the above embodiments, the cutting device can be a laser, or a die-cutting plate or roller.
In any of the above embodiments, the removable panel can be removed from the laminated film at least partly by gravitational force.
And in any of the above embodiments, the removable panel can be removed from the laminated film at least partly by application of suction thereto.
The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter.
The present invention is a is fresh produce package that prevents high water vapor generating produce from being prematurely desiccated, while at the same time preventing pooling of excess moisture within the package.
With reference to
With reference to
In embodiments, the first film layer has an MVTR (also referred to in the art as a “water” vapor transport rate, or “MVTR”) that is no greater than 3 g-mil/100 in2-day @ 100° F. and 90% relative humidity, while the second film layer has an MVTR that is greater than 10 g-mil/100 in2-day @ 100° F. and 90% relative humidity.
Gaps or openings 404 are provided in the first film layer 400 of the laminate film, thereby creating moisture transport windows (MTWs) 404 that are covered by the second film layer 402 but not by the first film layer 400. By controlling the number and sizes of these MTWs 404, the degree of moisture transport out of the package 200, 206 can be controlled, such that it is optimal for the intended contents 106. The laminate film 202 can also include microperforations 104 that penetrate through both of the film layers 400, 402, thereby providing a limited gas exchange that creates a modified gaseous atmosphere within the package. These embodiments are referred to herein as MCE-MAP packages.
Also disclosed herein is a method of manufacture of the disclosed MCE package. In some embodiments the first 400 and second 402 film layers are adhesively laminated to each other. With reference to
A second, high water transport layer 402, such as a nylon, PLA or cellulose film layer 402, is fed from a second feed roller 510 and bonded to the first film layer 400 by laminating rollers 512 that apply pressure and/or heat to bond the second layer 402 to the first layer 400. The resulting laminate film 202 is taken up by a receiving roller 514.
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The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. Each and every page of this submission, and all contents thereon, however characterized, identified, or numbered, is considered a substantive part of this application for all purposes, irrespective of form or placement within the application. This specification is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.
Although the present application is shown in a limited number of forms, the scope of the invention is not limited to just these forms, but is amenable to various changes and modifications. The disclosure presented herein does not explicitly disclose all possible combinations of features that fall within the scope of the invention. The features disclosed herein for the various embodiments can generally be interchanged and combined into any combinations that are not self-contradictory without departing from the scope of the invention. In particular, the limitations presented in dependent claims below can be combined with their corresponding independent claims in any number and in any order without departing from the scope of this disclosure, unless the dependent claims are logically incompatible with each other.
This application claims the benefit of U.S. Provisional Application No. 63/394,688, filed Aug. 3, 2022, which is herein incorporated by reference in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63394688 | Aug 2022 | US |
