Patent Application
20080310776
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1. Field of the Invention
The present invention relates generally to pouches, and particularly to a flow channel that may be used to evacuate a pouch.
2. Description of the Background of the Invention
Pouches are typically used for storage and preservation of perishable contents such as food. Perishable contents may be made to last longer with less degradation if stored under vacuum. Evacuable thermoplastic pouches have been designed to work with a vacuum source to allow storage of contents under vacuum. However, a problem with evacuating a thermoplastic pouch is that the pouch has flexible walls that are forced together into contact with one another as a result of the evacuation. Regions of the pouch interior may thus be blocked from the vacuum source by the contacting walls, making those regions difficult or impossible to evacuate. In response to this problem, evacuable thermoplastic pouches have been designed with various flow channels that function to prevent the pouch walls from coming into contact and blocking off regions of the pouch from the vacuum source.
One such pouch has a thick textured porous sheet that is affixed to an inner surface of a pouch wall over an aperture in the pouch wall. The sheet has dimensions similar to the pouch wall and functions to prevent the pouch walls from adhering to one another during evacuation. The sheet provides flow paths from the pouch interior to the aperture to prevent the pouch walls from adhering, thus preventing evacuation of the pouch. Another pouch has a strip of mesh or woven material that extends from the pouch interior to a mouth of the pouch. The strip of mesh may be inserted by a user or affixed to the pouch interior during manufacture. The strip may alternatively be comprised of a plurality of tubes held together to form the strip.
A further pouch has a strip of flexible plastic material attached to an interior of the pouch. The pouch has an aperture that extends through a wall of the pouch proximate an end of the pouch. The strip has a flat base and a plurality of ribs disposed lengthwise on one side of the base. A first end of the strip is attached to the interior of the pouch opposite the aperture. A second end of the strip is attached to a region of the interior that is at an opposite end of the pouch from the aperture. The ribs provide fluid communication between the aperture and the entire length of the strip.
Other pouches have protuberances that are extruded integrally with a sidewall or embossed onto a sidewall of the pouch between an interior of the pouch and an evacuation aperture. Each protuberance has a body that extends away from the sidewall between a base end and a distal end. The body has parallel side walls or is generally tapered from the base end to the smaller distal end. The protuberances may take the form of discrete shapes or may be joined to form ridges. The protuberances may also be arranged irregularly or formed into patterns. Channels formed between the protuberances provide fluid communication between the evacuation aperture and the interior of the pouch.
Yet another pouch has one or more wall panels that are formed from a material that is pressed between rollers to impart a corrugated cross-section to the material. Grooves and ridges formed by the rollers are imparted on an angle with respect to the direction of forming. The material is folded upon itself to form the pouch with the wall panels, wherein the pouch has grooves and ridges in each wall panel that intersect with grooves and ridges on an opposing wall panel. The intersecting grooves and ridges prevent the wall material from flattening under evacuation, thereby creating air channels throughout the pouch.
Still another pouch has a pattern of channels on a sidewall that is created by pressing a melt-extruded resin between rollers. The channels have baffles that allow gases to escape from the pouch, yet trap liquid within the pouch. Another pouch has at least one sidewall that has a zigzag pattern of channels or ridges formed therein or thereon, respectively.
Pouches that have flow channels may have regions of the pouch interior blocked from a vacuum source by an opposing sidewall that has entirely collapsed into a channel due to the inherent flexibility of the opposing sidewall material. Narrower flow channels can lessen blockage caused by the collapsed opposite sidewall, but also have decreased flow volume. Sidewalls made of more rigid material can also lessen blockage by limiting collapse, but necessarily have less flexibility.
According to one aspect of the invention, a pouch includes first and second opposing pouch walls and a plurality of flow channel protuberances that defines a flow channel between the first and second pouch walls and is disposed on an inner surface of at least one of the first or second pouch walls. At least one of the plurality of protuberances includes a first component that extends from the at least one of the first or second pouch walls and a second component that extends at a non-zero angle from the first component. The flow channel extends between an opening of the pouch and a portion of an interior of the pouch that is spaced from the opening.
According to another aspect of the invention, a pouch includes first and second opposing pouch walls. A flow channel profile is disposed on an inner surface of the first pouch wall, and a complementary groove is disposed on an inner surface of the second pouch wall to releasably engage with the flow channel profile to define a flow channel between the first and second pouch walls. The flow channel extends between an opening of the pouch and a portion of an interior of the pouch that is spaced from the opening.
According to yet another aspect of the invention, a pouch includes a pouch wall and a flow channel profile, wherein the flow channel profile includes a first component extending from the pouch wall and a second component extending at a non-zero angle from the first component. The flow channel profile is disposed on an inner surface of the pouch wall to define a flow channel disposed between the pouch wall and an opposing surface and that extends between an opening of the pouch and a portion of an interior of the pouch that is spaced from the opening.
Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description, wherein similar structures have similar reference numerals.
Referring to
A closure mechanism 62 extends across the pouch 50 proximate the mouth 58. The closure mechanism 62 allows the pouch 50 to be repeatedly opened and closed. When occluded, the closure mechanism 62 provides an airtight seal such that a vacuum may be maintained in the pouch interior 60 for a desired period of time, such as days, months, or years, when the closure mechanism is sealed fully across the mouth 58. The closure mechanism 62 comprises first and second closure elements (not shown) that are attached respectively to the inner surfaces 72 and 84 of the first and second sidewalls 52 and 54. The first closure element includes one or more interlocking closure profiles (not shown), and the second closure element also includes one or more interlocking closure profiles (not shown). The first and second interlocking closure profiles may be male and female closure profiles, respectively. However, the configuration and geometry of the interlocking profiles or closure elements disclosed herein may vary.
In a further embodiment, one or both of the first and second closure elements (not shown) may include one or more textured portions, such as a bump or crosswise groove in one or more of the first and second closure profiles in order to provide a tactile sensation, such as a series of clicks, as a user draws the fingers along the closure mechanism 62 to seal the closure elements across the mouth 58. In another embodiment, the first and second interlocking closure profiles (not shown) include textured portions along the length of each profile to provide tactile and/or audible sensations when closing the closure mechanism 62. In addition, protuberances, for example ridges (not shown), may be disposed on the inner surfaces 72, 84 of the respective first and second sidewalls 52, 54 proximate the mouth 58 to provide increased traction in a convenient area for a user to grip, such as a gripping flange, when trying to open the sealed pouch 50. Further, in some embodiments, a sealing material such as a polyolefin material or a caulking composition such as silicone grease may be disposed on or in the interlocking profiles or closure elements to fill in any gaps or spaces therein when occluded. The ends of the interlocking profiles or closure elements may also be welded or sealed by ultrasonic vibrations as is known in the art. Illustrative interlocking profiles, closure elements, sealing materials, tactile or audible closure elements, and/or end seals useful in the present invention include those disclosed in, for example, Pawloski U.S. Pat. No. 4,927,474, Dais et al. U.S. Pat. Nos. 5,070,584, 5,478,228, and 6,021,557, Tomic et al. U.S. Pat. No. 5,655,273, Sprehe U.S. Pat. No. 6,954,969, Kasai et al. U.S. Pat. No. 5,689,866, Ausnit U.S. Pat. No. 6,185,796, Wright et al. U.S. Pat. No. 7,041,249, Pawloski et al. U.S. Pat. No. 7,137,736, Anderson U.S. Patent Application Publication No. 2004/0091179, Pawloski U.S. Patent Application Publication No. 2004/0234172, Tilman et al. U.S. Patent Application Publication No. 2006/0048483, and Anzini et al. U.S. Patent Application Publication Nos. 2006/0093242 and 2006/0111226. Other interlocking profiles and closure elements useful in the present invention include those disclosed in, for example, U.S. patent application Ser. No. 11/725,120, filed Mar. 16, 2007, and Attorney Docket Nos. J-4712, J-4714B, and J-4673 (U.S. Patent Application Nos. to be assigned), each filed on the same day as the present application. It is further appreciated that the interlocking profiles or closure elements disclosed herein may be operated by hand, or a slider (not shown) may be used to assist in occluding and de-occluding the interlocking profiles and closure elements.
An exterior 64 of the pouch 50 is also shown in
Although not shown, in some embodiments an evacuation pump or device may be used to evacuate fluid from the pouch 50 through, for example, the valve 68 disposed in one of the sidewalls 52, 54, or in the closure mechanism 62 or one of the side edges 56a-56c of the pouch. Illustrative evacuation pumps or devices useful in the present invention include those disclosed in, for example, Attorney Docket No. J-4705, (U.S. Patent Application No. to be assigned), filed on the same day as the present application.
In a first embodiment shown in
Referring to
Further, a solid material that includes fixed or supported portions is displaced at an unsupported portion in response to a force applied to the unsupported portion. The amount of displacement depends upon, for example, the span of the unsupported portion, the amount and distribution of force applied thereto, and/or a material property of the solid material called the flex modulus. For example, in the pouch 50 being evacuated, unsupported portions of each of the first and second sidewalls 52, 54 may sag into the flow channel 74 by an amount that depends upon spacing between respective ends of the protuberances 70, the flex modulus for the material in each of the first and second sidewalls, and/or the level of vacuum drawn on the pouch. Assuming a given composition for the first and second sidewalls 52, 54, and a given level of vacuum drawn on the pouch, the amount of sag of each of the first and second sidewalls therefore depends on the spacing between respective ends of the protuberances 70. The increased surface area 82 makes contact over an increased area of the inner surface 84 of the second sidewall 54, thereby leaving less of the second sidewall 54 disposed over the flow channel 74 unsupported during evacuation of the pouch 50. Inhibiting sag of the first and second sidewalls 52, 54 into the flow channels 74 allows the flow channels to remain open for a longer period of time while fluid is being evacuated therefrom and from the pouch.
Referring next to
The flow channel protuberances 70 may also depend from a first side 94 of a base member 96, as illustrated in
Referring next to
Referring now to
Referring next to
Illustratively, the second component 108 may extend laterally away from the first component 106 perpendicular to the first component 106, as shown in profiles 100a and 100e in
Referring next to
The flow channel profiles 100a-100e and 200a-200c may be straight or curved. The profiles 100a-100e and 200a-200c may be parallel to one another, or in other embodiments not shown, may extend radially away from the opening 66a-66c in an expanding sunburst configuration, or may have any other configuration such that the continuous flow channels 74 provide fluid communication between the opening 66a-66c and a portion of the pouch interior 60 spaced from the opening when the pouch 50 is under vacuum pressure.
Although not shown, one or both sidewalls, such as the second sidewall 54, may also be embossed or otherwise textured with a pattern, such as a diamond pattern, on one or both surfaces spaced between the bottom edge 56b and the closure mechanism 62, or a separate textured and embossed patterned wall may be used to provide additional flow channels (not shown) within the pouch interior 64. Illustrative flow channels useful in the present invention include those disclosed in Zimmerman et al. U.S. Patent Application Publication No. 2005/0286808 and Tilman et al. U.S. Patent Application Publication No 2006/0048483.
In one embodiment, the first and second sidewalls 52, 54 and/or the closure mechanism 62 are formed from thermoplastic resins by known extrusion methods. For example, the sidewalls 52, 54 may be independently extruded of thermoplastic material as a single continuous or multi-ply web, and the closure mechanism 62 may be extruded of the same or different thermoplastic material(s) separately as continuous lengths or strands. Illustrative thermoplastic materials include polypropylene (PP), polyethylene (PE), metallocene-polyethylene (mPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), biaxially-oriented polyethylene terephthalate (BPET), high density polyethylene (HDPE), polyethylene terephthalate (PET), among other polyolefin plastomers and combinations and blends thereof. Further, the inner surfaces 152, 154 of the respective sidewalls 52, 54 or a portion or area thereof may, for example, be composed of a polyolefin plastomer such as an AFFINITY™ resin manufactured by Dow Plastics. Such portions or areas include, for example, the area of one or both of the sidewalls 52, 54 proximate and parallel to the closure mechanism 60 to provide an additional cohesive seal between the sidewalls when the pouch 50 is evacuated of fluid. One or more of the sidewalls 52, 54 in other embodiments may also be formed of air-impermeable film. An example of an air-impermeable film includes a film having one or more barrier layers, such as an ethylene-vinyl alcohol copolymer (EVOH) ply or a nylon ply, disposed between or on one or more of the plies of the sidewalls 52, 54. The barrier layer may be, for example, adhesively secured between the PP and/or LDPE plies to provide a multilayer film. Other additives such as colorants, slip agents, and antioxidants, including for example talc, oleamide or hydroxyl hydrocinnamate may also be added as desired. In another embodiment, the closure mechanism 62 may be extruded primarily of molten PE with various amounts of slip component, colorant, and talc additives in a separate process. The fully formed closure mechanism 62 may be attached to the pouch body using a strip of molten thermoplastic weld material, or by an adhesive known by those skilled in the art, for example. Other thermoplastic resins and air-impermeable films useful in the present invention include those disclosed in, for example, Tilman et al. U.S. Patent application publication No 2006/0048483.
The protuberances 70, and flow channel profiles 100, 100a-100e, and 200a-200c as disclosed herein may be composed of any thermoplastic material such as would be used for the first and second sidewalls 52 and 54 of the pouch 50 as disclosed herein. Illustratively, the protuberances 70, and flow channel profiles 100, 100a-100e, and 200a-200c may, for example, be composed of a polyolefin plastomer such as an AFFINITY™ resin manufactured by Dow Plastics.
The resealable pouch 50 described herein can be made by various techniques known to those skilled in the art including those described in, for example, Geiger, et al., U.S. Pat. No. 4,755,248. Other useful techniques to make a resealable pouch include those described in, for example, Zieke et al., U.S. Pat. No. 4,741,789. Additional techniques to make a resealable pouch include those described in, for example, Porchia et al., U.S. Pat. No. 5,012,561. Additional examples of making a resealable pouch as described herein include, for example, a cast post applied process, a cast integral process, and/or a blown process.
Flow channels within a pouch may be used to evacuate fluid from the pouch, thereby allowing pouch contents, such as food, to remain fresher for extended periods of time. Flow channels allow a vacuum source to reach interior regions of the pouch that are spaced from the vacuum source. The flow channels herein are defined by structures having first and second components that together provide an increased surface area that prevents collapse of an opposing pouch wall when the pouch is subjected to vacuum evacuation.
Numerous modifications to the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is presented for the purpose of enabling those skilled in the art to make and use the invention and to teach the best mode of carrying out same. The exclusive rights to all modifications which come within the scope of the appended claims are reserved. All patents, patent publications and applications, and other references cited herein are incorporated by reference herein in their entirety.
