Patent Publication Number: US-9428306-B2

Title: Gastight valve strip for a reclosable container

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of copending U.S. patent application Ser. No. 13/471,576, filed May 15, 2012, which is a divisional of U.S. patent application Ser. No. 12/383,127, filed Mar. 20, 2009, now U.S. Pat. No. 8,197,139, issued Jun. 12, 2012, which is a continuation-in-part of application Ser. No. 11/818,591, filed Jun. 15, 2007, now U.S. Pat. No. 7,874,731, issued on Jan. 25, 2011, which are incorporated by reference herein in their entirety. 
    
    
     REFERENCE REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     SEQUENTIAL LISTING 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a gastight valve strip that may be used on a reclosable container. 
     2. Description of the Background of the Invention 
     Food or other perishables are often stored in reclosable containers such as thermoplastic pouches. To keep food stored inside a pouch fresh for an extended period, a user may evacuate gas out of the pouch before completely sealing a closure mechanism of the pouch. Other reclosable pouches have been developed that have a valve that allows gas to be evacuated from the pouch after the closure mechanism has already been sealed. 
     Some pouch valves have a patch of thermoplastic material covering an aperture in a pouch wall and sealed over a limited area of the pouch wall around a periphery of the patch. The patch has an aperture therethrough that is offset from the aperture in the pouch wall. Pressure from outside of the pouch forces the patch against the pouch wall, keeping the valve closed. However, pressure from within the pouch forces the patch to separate from the pouch wall to allow air to flow through both apertures and out of the pouch. Another valve has a highly cohesive fluid in the space between the offset apertures to resist separation of the patch and the pouch wall. Still another valve has a porous layer of material secured over the aperture in the pouch wall, wherein the porous layer has a smaller area than the patch. 
     Other valves have a cover flap disposed over an aperture in a pouch wall, wherein the cover flap lacks an aperture. The valves have an unsealed edge that provides a path for escaping air. One such valve has a separator layer disposed between an adhesive layer disposed on an inner surface of the cover flap and an aperture in the pouch wall. The separator layer is smaller than the cover flap, but larger than the aperture, and is shaped so that the adhesive layer makes asymmetrical contact with the pouch wall around a periphery of the cover flap. Pressure from within the pouch forces a portion of the cover flap having a smaller adhesive contact area to separate from the pouch wall. The valve may also have an intermediate gas permeable layer between the separator layer and the aperture. 
     Another valve has a cover flap that is disposed across an entire width of a pouch wall. The flap overlays one or more apertures in the pouch wall to allow air to escape from within the pouch and to prevent air from entering the pouch. 
     Yet another valve for a pouch has a patch that is disposed across an entire width of a pouch wall and is sealed to the pouch wall around a periphery of the patch. A first plurality of apertures extending through the pouch wall is offset from a second plurality of apertures extending through the patch. An adhesive is disposed between the first and second pluralities of apertures. Pressure from within the pouch overcomes the adhesive and forces the patch to separate from the pouch wall to allow air to escape from within the pouch. 
     A still further valve has a patch that is sealed around a periphery of the valve over an inner or outer surface of a plastic tube. The patch may be oriented axially along a length of the tube, or circumferentially around the tube. The patch has a vent opening that is offset from a vent opening through the tube surface. A vent seal zone is defined between the patch and the tube surface. The tube is sealed on both ends such that pressure from within the tube forces the patch to separate from the tube surface to allow air to escape from within the tube. 
     Yet another valve has first and second zipper flanges sealed to an inside surface of a pouch wall. A line of apertures is disposed through the pouch wall, wherein the first zipper flange is attached to the pouch wall on a first side of the apertures and the second zipper flange is attached to the pouch wall on a second, opposite side of the apertures. An air path is formed between the first and second zipper flanges and the apertures. Pressure from within the pouch forces the second flange away from the first flange and pressure from outside the pouch forces the second flange into contact with the first flange. Alternatively, the second flange is eliminated, and the pouch wall on the second side of the line of apertures makes contact with the first flange. In another variation, one or more apertures disposed through the first flange are covered in flap fashion by the second flange. 
     Multiple layers of film material may be joined together, for example, by ultrasonic vibration, heat sealing, an adhesive, or by other means, as known to one skilled in the art, to form gastight sealed regions between the multiple layers. In one instance, multiple layers of film are bonded together by an intermittent ultrasonic bond. The intermittent bond has a number of bond points, spaced close together along a line to provide a leak-proof seal between the layers. Material displaced from each of the bond points may make contact with or may be close enough to material displaced from an adjacent bond point to block passage of fluid therebetween. 
     Sealed regions between multiple layers of film material may be formed by application of an adhesive between the layers. Adhesives generally provide an enduring gastight seal, but environmental conditions may cause the gastight seal to degrade. For example, an adhesive may suffer from loss of tact in cold conditions, or may become excessively fluid in hot or microwave conditions, resulting in flow of the adhesive into areas of the container where the adhesive may not be intended to go, such as into contact with food. A thermal seal may be more resistant than an adhesive seal to degradation caused by environmental conditions. A thermal seal between multiple layers of film material may be created by application of energy in the form of heat and/or ultrasonic vibration to a target sealing region. The applied energy may cause material within the target region to become molten, and to thereby bond the layers in a gastight seal. However, the molten material may flow away from the target region, and cause expansion and/or shrinkage of the film material surrounding the target region, which may form wrinkles in one or more layers of the film material outside of the target region. 
     SUMMARY OF THE INVENTION 
     According to one aspect, the present invention provides a gastight valve strip for a reclosable container. The reclosable container has a container aperture through a sidewall of the container. The valve strip includes a first film layer having a periphery, a second film layer opposing the first film layer and being attached to the first film layer, the first and second film layers adapted to be disposed over a container aperture through a sidewall of the reclosable container, the second film layer comprising an attachment surface being adapted to be sealed to the sidewall of the reclosable container, the attachment surface comprising a patterned portion that defines a region of flow channels, wherein opposing surfaces of the first and second film layers form a substantially gastight seal therebetween upon contact of the first and second film layers to each other, a first film layer aperture extending through the first film layer, the first film layer aperture being in fluid communication with an exterior side of the valve strip, and a second film layer aperture extending through the second film layer, the second film layer aperture being offset and spaced apart from the first film layer aperture, wherein the second film layer aperture is configured to be in fluid communication with the container aperture through the patterned portion of the attachment surface, the patterned portion extending along the attachment surface and into the second film layer aperture, in which at least a portion of a surface of the second film layer opposite to the attachment surface comprises a patterned portion to provide flow channels in fluid communication with the second film layer aperture, such that a vacuum pressure dispersed over the first film layer aperture and the flow channels separates the first film layer and the second film layer, to allow gas to exhaust from the reclosable container through the container aperture. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a reclosable pouch incorporating a valve and illustrating valve layers peeled up for clarity; 
         FIG. 1A  is an isometric view of a reclosable pouch illustrating a textured pattern on a sidewall; 
         FIG. 2  is a fragmentary cross-sectional view of an embodiment of a valve taken generally along the lines  2 - 2  of  FIG. 1A , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 3  is a fragmentary cross-sectional view taken generally along the lines  3 - 3  of  FIG. 1A , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 4  is a fragmentary cross-sectional view taken generally along the lines  3 - 3  of  FIG. 1A , with the first and second layers of the valve of the first embodiment separated and with portions behind with the plane of the cross section omitted for clarity; 
         FIG. 4A  is a fragmentary cross-sectional view of another embodiment of a valve taken generally along the lines  3 - 3  of  FIG. 1A , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 4B  is a fragmentary cross-sectional view of a further embodiment of a valve taken generally along the lines  3 - 3  of  FIG. 1A , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 4C  is a fragmentary cross-sectional view of the valve of  FIG. 3  illustrating embossing on an interior surface of a pouch sidewall, with portions behind the plane of the cross section omitted for clarity; 
         FIG. 5  is a fragmentary cross-sectional view of another embodiment of a valve taken generally along the lines  3 - 3  of  FIG. 1A , with first and second layers thereof separated and with portions behind the plane of the cross section omitted for clarity; 
         FIG. 6  is a fragmentary plan view of a first sidewall of a pouch illustrating a further embodiment of a valve; 
         FIG. 6A  is a plan view of a first sidewall of a pouch illustrating a still further embodiment of a valve; 
         FIG. 6B  is a fragmentary plan view of a first sidewall of a pouch illustrating another embodiment of intermittent spot seals; 
         FIG. 6C  is a cross-sectional view of one possible embodiment of the intermittent spot seal of  FIG. 6B  taken generally along the lines  6 C- 6 C of  FIG. 6B ; 
         FIG. 6D  is a cross-sectional view of another possible embodiment of the intermittent spot seal of  FIG. 6B  taken generally along the lines  6 D- 6 D of  FIG. 6B ; 
         FIG. 6E  is a close-up view of an intermittent spot seal that comprises individual circular spots; 
         FIG. 6F  is a close-up view of an intermittent spot seal that comprises individual triangular spots; 
         FIG. 6G  is a fragmentary plan view of an embodiment of a valve; 
         FIG. 6H  is a fragmentary plan view of another embodiment of a valve; 
         FIG. 7  is a fragmentary cross-sectional view taken generally along the lines  7 - 7  of  FIG. 6 , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 8  is a fragmentary cross-sectional view taken generally along the lines  2 - 2  of  FIG. 1A  and illustrating yet another embodiment of a valve, with portions behind the plane of the cross section omitted for clarity; 
         FIG. 8A  is a fragmentary cross-sectional view taken generally along the lines  8 A- 8 A of  FIG. 6A  and illustrating another embodiment of a valve, with portions behind the plane of the cross section omitted for clarity; 
         FIG. 9  is a fragmentary cross-sectional view taken generally along the lines  2 - 2  of  FIG. 1A  and illustrating a still further embodiment of a valve, with portions behind the plane of the cross section omitted for clarity; 
         FIG. 9A  is a fragmentary cross-sectional view taken generally along the lines  9 A- 9 A of  FIG. 6A  and illustrating another embodiment of a valve, with portions behind the plane of the cross section omitted for clarity; 
         FIG. 10  is an isometric view of the reclosable pouch illustrating still another embodiment of a valve with valve layers peeled up for clarity; 
         FIG. 11  is an isometric view of the reclosable pouch illustrating a yet further embodiment of a valve with valve layers peeled up for clarity; 
         FIG. 12  is a fragmentary cross-sectional view taken generally along the lines  12 - 12  of  FIG. 11 , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 13  is a partial cross-sectional view depicting layers and plies for a valve and taken generally along the lines  3 - 3  of  FIG. 1A , with portions behind the plane of the cross section omitted for clarity; 
         FIGS. 14 and 15  are partial cross-sectional views, similar to the view of  FIG. 13  illustrating alternative constructions of layers and plies for valves herein; 
         FIG. 16  is an isometric view of another embodiment of a valve on a container; 
         FIG. 17A  is a cross-sectional view taken generally along the lines  17 - 17  of  FIG. 16 , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 17B  is a cross-sectional view taken generally along the lines  17 - 17  of  FIG. 16  and illustrating yet another embodiment of a valve, with portions behind the plane of the cross section omitted for clarity; 
         FIG. 18  is an isometric view of a still further embodiment of a valve on a container; 
         FIG. 19  is a fragmentary cross-sectional view taken generally along the lines  19 - 19  of  FIG. 18 , with portions behind the plane of the cross section omitted for clarity; 
         FIG. 20  is a plan view of an embodiment of an independently constructed valve applied to a container; 
         FIG. 21  is a cross-sectional view taken generally along the lines  21 - 21  of  FIG. 20 ; 
         FIG. 22  is a plan view of another embodiment of an independent constructed valve applied to a container; and 
         FIG. 23  is a cross-sectional view taken generally along the lines  23 - 23  of  FIG. 22 . 
     
    
    
     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. 
     DETAILED DESCRIPTION 
     While the present invention may be embodied in many forms, several embodiments are discussed herein, with the understanding that embodiments illustrated are to be considered only as an exemplification of the invention and are not intended to limit the disclosure to the embodiments illustrated. For example, while a reclosable pouch and a reclosable hard-walled container are shown, any other container, such as reclosable or non-reclosable, soft- or hard-walled, to which a valve can be applied to evacuate gas therefrom, can also be used with the present invention. 
     Turning now to the figures, a reclosable thermoplastic pouch  50 , illustrated in  FIG. 1 , includes a first sidewall  52 , a second sidewall  54 , and a valve  40 . The first and second sidewalls  52  and  54  are joined around the three side edges  56   a - 56   c  by heat sealing, adhesive, ultrasonic vibration, or other sealing method known in the art, to define an opening  56  leading to an interior  58 . Alternatively, bottom side edge  56   b  may be a fold line between the first and second sidewalls  52  and  54 . A closure mechanism  60  extends across a full width  62  of the pouch  50 , proximate to the opening  56 . The closure mechanism  60  allows the pouch  50  to be repeatedly opened and closed. When occluded, the closure mechanism  60  preferably provides a gastight seal, such that a vacuum may be maintained in the pouch interior  58  for a desired period of time, such as days, months, or years, when the closure mechanism is sealed fully across the opening  56 . 
     The closure mechanism  60  comprises first and second complementary interlocking closure elements  200 ,  202  (illustratively shown in  FIG. 12 ) that are disposed along the respective inner surfaces  152  and  154  of the first and second sidewalls  52  and  54 . The first interlocking closure element  200  includes one or more interlocking closure profiles  200   a  (illustratively shown in  FIG. 12 ), and the second interlocking closure element  202  also includes one or more interlocking closure profiles  202   a  (illustratively shown in  FIG. 12 ). The first and second interlocking closure profiles  200   a ,  202   a  may be male and female closure profiles, respectively, as shown. However, the configuration and geometry of the interlocking profiles  200   a ,  202   a  or closure elements  200 ,  202  disclosed herein may vary. 
     In a further embodiment, one or both of the first and second complementary interlocking closure elements  200 ,  202  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  200   a ,  202   a  in order to provide a tactile sensation, such as a series of clicks, as a user draws the fingers along the closure mechanism  60  to seal the closure elements across the opening. In another embodiment, the first and second interlocking closure profiles  200   a ,  202   a  include textured portions along the length of each profile to provide tactile and/or audible sensations when closing the closure mechanism  60 . In addition, protuberances, for example, ridges (not shown), may be disposed on the inner surfaces  152 ,  154  of the respective first and second sidewalls  52 ,  54 , proximate to the opening  56 , 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  60 . 
     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  200   a ,  202   a  or closure elements  200 ,  202 , to fill in any gaps or spaces therein when occluded. The ends of the interlocking profiles  200   a ,  202   a  or closure elements  200 ,  202  may also be welded or sealed to provide an end-stomp seal between the first and second closure elements  200 ,  202  by, for example, crushing, ultrasonic vibration, and/or application of heat, as is known in the art. Illustrative interlocking profiles, closure elements, sealing materials, tactile or audible closure elements, and/or end-stomps 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, Tilman et al. U.S. Pat. No. 7,290,660, Anderson U.S. Patent Application Publication No. 2004/0091179, now U.S. Pat. No. 7,305,742, Pawloski U.S. Patent Application Publication No. 2004/0234172, now U.S. Pat. No. 7,410,298, and Anzini et al. U.S. Patent Application Publication No. 2006/0093242 and No. 2006/0111226, now U.S. Pat. No. 7,527,585. 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, now U.S. Pat. No. 7,886,412, U.S. patent application Ser. No. 11/818,585, now U.S. Pat. No. 7,857,515, Ser. No. 11/818,593, now U.S. Pat. No. 7,784,160, and Ser. No. 11/818,586, now U.S. Pat. No. 7,946,766, each filed on Jun. 15, 2007, and U.S. patent application Ser. No. 12/146,015, filed on Jun. 25, 2008, which was published as U.S. Patent Application Publication No. 2009/0324141 on Dec. 31, 2009, now U.S. Pat. No. 8,530,676. 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. 
     The resealable pouch 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. 
     A first layer  64  of a film material may be disposed on the first sidewall  52 . A second layer  66  of film material may also be disposed on the first sidewall  52  between the first sidewall and the first layer  64 . Each of the first and second layer  64 ,  66  may be disposed on a portion of the first sidewall  52 , or across the full width  62  of the first sidewall  52 , as illustrated in  FIG. 1 . Further, each of the first and second layer  64  and  66  may be comprised of one or more plies of material. An exterior  68  of the pouch  50  is also shown in  FIG. 1 . 
     Referring next to an embodiment of the valve  40 , as seen in  FIG. 2 , the second layer  66  has an overlap region  70  that overlaps the first sidewall  52 . The overlap region  70  comprises the entire second layer  66 . A projection  72  of the overlap region  70  of the second layer  66  is shown by the area outlined by the dashed lines in  FIG. 1 . 
     Referring now to  FIGS. 1 and 2 , a first aperture  74  extends through the first layer  64  and a second aperture  76  extends through the second layer  66 . The first layer  64  is attached to the second layer  66  at a portion of the second layer. Illustratively, the first layer  64  is attached to the second layer  66  around the entire periphery of the second layer, or along one or more peripheral edges  94 ,  98 ,  194 ,  198  of the second layer. The first and second layers  64  and  66  are attached to each other by a thermal seal  78   a  along the peripheral edge  94  and by a thermal seal  78   b  along the peripheral edge  98 . The thermal seals  78   a ,  78   b  may be continuous, as shown in  FIG. 6 , or may be intermittent spot seals  178   a ,  178   b , as shown in  FIG. 6A . Each of the thermal seals  78   a ,  78   b ,  178   a ,  178   b  may be a heat seal, a seal created by ultrasonic vibration, or some other thermal seal as is known in the art. 
     The second layer  66  is sealed to the first sidewall  52  at a periphery of the overlap region  70  of the second layer  66 , including, for example, around a periphery of the overlap region or on at least a portion of the overlap region. In the embodiment of  FIG. 2 , a thermoplastic weld layer  80  is disposed coextensively with the second layer  66  between the sidewall  52  and the second layer  66  to seal the entire second layer  66  to the first sidewall  52 . The thermoplastic weld layer  80  may be composed of any suitable thermoplastic material, such as, for example, polypropylene. 
     A third aperture  82  extends through the thermoplastic weld layer  80  and a fourth aperture  84  extends through the first sidewall  52 , as illustrated in  FIG. 2 . The second, third, and fourth apertures,  76 ,  82 , and  84  are arranged to be coincident along a line perpendicular to the sidewall  52 , to allow fluid communication of the second aperture  76  with the interior  58  of the pouch  50 . The first aperture  74  in the first layer  64  is in fluid communication with the exterior  68  of the pouch  50 . 
     One or both sidewalls, such as the second sidewall  54 , may also be embossed or otherwise textured with a pattern  254 , as illustrated in  FIGS. 1A and 4C . One or both surfaces of the second sidewall  54 , for example, the inner surface  154 , may be embossed or textured between the bottom side edge  56   b  and the closure mechanism  60 , or a separate textured or embossed patterned wall may be used to provide flow channels (not shown) within the pouch interior  58 . In one embodiment, the second sidewall  54  is embossed with a diamond pattern  254 , for example, as shown in  FIGS. 1A and 4C , wherein the pattern extends from just beneath the closure mechanism  60  to the bottom side edge  56   b  and opposes the second aperture  76  that is in fluid communication with the interior  58  of the pouch  50 . The flow channels may provide fluid communication between the pouch interior  58  and the valve  40  when gas is being drawn through the valve  40 . Illustrative flow channels useful in the present invention include those disclosed in Zimmerman et al. U.S. Patent Application Publication No. 2005/0286808, now U.S. Pat. No. 7,726,880, and Tilman et al. U.S. Pat. No. 7,290,660. Other flow channels useful in the present invention include those disclosed in, for example, U.S. patent application Ser. No. 11/818,584, filed on Jun. 15, 2007, now U.S. Pat. No. 7,887,238. 
     Referring next to  FIG. 3 , the first aperture  74  is offset from the second, third, and fourth apertures  76 ,  82 , and  84 . The first and second layers  64  and  66  are in direct contact in an intermediate seal region  86  between the offset first and second apertures  74  and  76 . Although the first and second apertures  74  and  76  are shown in  FIG. 3  to be offset from one another along the width  62  of the pouch  50 , in all of the embodiments described herein, the first and second apertures may be offset in any relative orientation that allows for direct contact of the first and second layers  64  and  66  in the intermediate seal region  86  between the first and second apertures. A substantially gastight seal is formed between the first and second layers  64  and  66  by direct contact of the first layer to the second layer. 
     In one embodiment, the first and second sidewalls  52 ,  54  and/or the closure mechanism  60  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  60  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 ppolyethylene terephthalate (BPET), high density polyethylen (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 to and parallel to the closure mechanism  60 , to provide an additional cohesive seal between the sidewalls  52 ,  54  when the pouch  50  is evacuated. One or more of the sidewalls  52 ,  54  in other embodiments may also be formed of an 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  60  may be extruded primarily of molten PE with various amounts of slip component, colorant, and/or talc additives in a separate process. The fully formed closure mechanism  60  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. Pat. No. 7,290,660. 
     With reference to  FIG. 4 , and not wishing to be bound by theory, the operation of the embodiment of  FIGS. 2 and 3  will now be described, it being believed that the other embodiments discussed herein operate in a similar fashion. Gas pressure from the exterior  68  of the pouch  50  that is greater than or equal to a gas pressure of the interior  58  of the pouch  50  compresses the pouch  50  and forces the first and second layers  64  and  66  into contact with each other, thereby forming a substantially gastight seal. Further, an opening region  88  of the first layer  64  disposed directly over the second aperture  76 , is subject to any pressure imbalance between the interior and exterior  58  and  68  of the pouch  50 . Increased gas pressure from the interior  58  of the pouch  50  forces the opening region  88  of the first layer  64  away from the second layer  66  and, thereafter, a remainder of the first layer  64  is forced away from the second layer  66 . Separation of the opening region  88  from the second aperture  76  allows higher pressure gas from within the interior  58  of the pouch  50  to spread away from the second aperture into a space  158  formed between the layers  64  and  66 . An expanding zone of higher pressure gas applies a pressure imbalance to a corresponding expanding region of the first layer  64 . When the expanding zone of higher pressure gas reaches the first aperture  74 , the higher pressure gas escapes through the first aperture to the exterior  68  of the pouch  50 . At this point, gas can escape freely from the interior  58  of the pouch  50  to the exterior  68  of the pouch following a path  90 , as depicted by the curved line and arrow in  FIG. 4 . 
     The valve  40  provides a fluid path with direct fluid communication between the interior  58  and the exterior  68  of the pouch  50 . Although not shown, in some embodiments, a second valve may be disposed in or through the closure mechanism  60  or in one of the side edges  56   a - 56   c  of the pouch. Illustrative second valves useful in the present invention include those disclosed in, for example, Newrones et al. U.S. Patent Application Publication No. 2006/0228057, now U.S. Pat. No. 7,837,387. Other valves useful in the present invention include those disclosed in, for example, U.S. patent application Ser. Nos. 11/818,586, and 11/818,592, each filed on Jun. 15, 2007, now U.S. Pat. Nos. 7,946,766 and 7,967,509, respectively. 
     In use, application of a vacuum pressure over the exterior of the first and second apertures  74  and  76  causes the interior  58  of the pouch  50  below the first and second apertures to have a greater pressure than the exterior. Vacuum pressure may be applied by an evacuation pump or a device or any other source of vacuum pressure known in the art, for example, by placing a vacuum cup of the evacuation pump in contact with an outer surface of the pouch and drawing a vacuum on an interior of the vacuum cup, thereby creating an expansive pressure imbalance and holding down the first and second layers  64  and  66  around the pressure imbalance. Illustrative evacuation pumps or devices useful in the present invention include those disclosed in, for example, U.S. patent application Ser. No. 11/818,703, filed on Jun. 15, 2007, now U.S. Pat. No. 8,096,329, and U.S. patent application Ser. No. 12/008,164, filed on Jan. 9, 2008, which was published as U.S. Patent Application Publication No. 2009/0175747 on Jul. 9, 2009, now U.S. Pat. No. 8,192,182. 
     In another embodiment, as illustrated in  FIG. 4A , a region on a surface of the second layer  66  that faces the first layer  64  and that is disposed between the first and second apertures  74 ,  76 , and bounded by the second aperture  76 , may also be embossed or otherwise textured with a pattern  65  to define a region of flow channels  67 . In a further embodiment, as illustrated in  FIG. 4B , a region on a surface of the first layer  64  that faces the second layer  66  and that is disposed between the first and second apertures  74 ,  76 , and at least partially overlapping the second aperture  76 , may also be embossed or otherwise textured with the pattern  65  to define the region of flow channels  67 . In these embodiments, the first and second layers  64  and  66  are in direct contact in an intermediate seal region  87  between the first aperture  74  and the region of flow channels  67 , which is in fluid communication with the interior  58  of the pouch  50 . In use, application of vacuum pressure over the exterior of the first aperture  74  and a portion of the region of flow channels  67  causes gas resident within the region of flow channels  67  to have a greater pressure than the exterior. 
     It is further contemplated that the pouch  50  may include a one-way valve disposed on at least one of the first and second pouch sidewalls and flow channels disposed on at least one of the first and second pouch sidewalls and in fluid communication with the one-way valve, and may be provided as a component of a kit or package that comprises a vacuum pump to evacuate gas from the interior of the pouch through the one-way valve. 
     Although not shown, a porous or adhesive layer disposed between one or more of the valve layers  64 ,  66  may also be desired in any of the embodiments disclosed herein. Examples of adhesives useful in the present invention include those described in, for example, Hamilton U.S. Pat. No. 7,004,632 or Mizuno U.S. Pat. No. 5,989,608. Examples of a porous material useful in the present invention include those described in, for example, Mizuno U.S. Pat. No. 5,989,608 or Shah et al. U.S. Patent Application Publication No. 2004/0223667, now U.S. Pat. No. 7,137,738. 
     In the creation of a thermal seal between two or more layers of thermoplastic material, energy and/or pressure may be applied to a target sealing region to at least partially melt one or more of the layers, such that melted portions between any two layers create a bond therebetween. A consequence of applying energy and/or pressure to melt the material in the target region may be that the melted material flows away from the target region. This flow of material away from the target region may form wrinkles in one or more of the layers. Such wrinkles may be aesthetically or otherwise undesirable. For example, such wrinkles may inhibit or prevent formation of a gastight seal between the wrinkled layers. However, the creation of wrinkles may be alleviated by several techniques. For example, in the creation of a heat seal, heat may be applied to an entire layer (or layers) to pre-heat the material prior to creating the heat seal. Further, heat may be applied to multiple layers of material from both a top side and a bottom side to alleviate uneven material expansion due to temperature gradients through the material. In the creation of a seal by ultrasonic vibration, a vibrating surface may be forced against the layers of material to melt the layers and to create a bond therebetween. Wrinkling may be alleviated in a desired region of the material by angling the vibrating surface away from the desired region to push the melted material away therefrom. 
     Wrinkling may also be alleviated by the use of intermittent spot seals to create a seal region. For example, referring to  FIGS. 6B-6D , the second layer  66  may be sealed to the first sidewall  52  by an intermittent spot seal  278   a  along the peripheral edge  94  and by an intermittent spot seal  278   b  along the peripheral edge  98 . In one embodiment, illustrated in  FIG. 6A , individual sealing spots of the intermittent spot seals  278   a  and  278   b  may be coincident with individual sealing spots of the respective intermittent spot seals  178   a  and  178   b . In another embodiment, as schematically illustrated in  FIGS. 6B-6D , the individual sealing spots of the intermittent spot seal  178   a  are staggered with respect to the individual sealing spots of the intermittent spot seal  278   a , and/or the individual sealing spots of the intermittent spot seal  178   b  are similarly staggered with respect to the individual sealing spots of the intermittent spot seal  278   b.    
     Optional strips  80   a ,  80   b  of the thermoplastic weld layer material may extend along the respective peripheral edges  94 ,  98 , as illustrated by dashed lines in  FIG. 6B . Each of the optional strips may be sandwiched between the second layer  66  and the first sidewall  52 , as illustrated in  FIG. 6D . An edge seal  279  may seal the edges  56   a  and  56   c.    
     Each of the individual sealing spots that comprise the intermittent spot seals  178   b  and  278   b  that are schematically illustrated in  FIGS. 6C and 6D  has a melt region around at least a portion thereof. For example, each of the individual sealing spots of the intermittent spot seal  278   b  may comprise molten material comprised of one or more of the second layer,  66 , the optional strip of thermoplastic weld layer material  80   b , and the first sidewall  52 . 
     Illustratively referring to  FIG. 6E , a generally curved intermittent spot seal  280  between two or more layers of thermoplastic material includes generally circular individual sealing spots  282 . Each of the circular individual sealing spots  282  may be surrounded by a generally symmetric melt region  284 . If the circular individual sealing spots  282  are not spaced sufficiently from one another, portions of the symmetric melt regions  284  of the adjacent circular individual sealing spots  282  may overlap, as shown by overlap regions  286 . Wrinkles  287  that are created in the thermoplastic material surrounding the symmetric melt regions  284  may be exacerbated by the overlap regions  286 . 
     Referring to  FIG. 6F , a portion of generally curved intermittent spot seals  288  includes generally triangular individual sealing spots  290 . Each of the triangular individual sealing spots  290  may be surrounded by a generally asymmetric melt region  291 . The wrinkles  287  may be less likely to form in this example than in the example described with regard to  FIG. 6E  above because, for example, the triangular individual sealing spots  290  are spaced sufficiently far apart, such that non-overlap regions  292  remain between the asymmetric melt regions  291 . Further, corner regions  291   a  of the asymmetric melt regions  291  opposite to the corners of the triangular individual sealing spots  290  are generally thinner than side regions  291   b  of the asymmetric melt regions  291  opposite to the sides of the triangular individual sealing spots  290 . Therefore, the wrinkles  287  may be less likely to form in localized areas of the thermoplastic material opposite to the corner regions  291   a  than the side regions  291   b.    
     In another embodiment, depicted in  FIG. 5 , the first and second layers  64  and  66 , and the thermoplastic weld layer  80 , are disposed on the interior  58  of the pouch  50 . In this embodiment, the opening region  88  of the second layer  66  is disposed directly over the first aperture  74  disposed in the first layer  64 . In all of the embodiments described herein, either the first aperture  74  or the second aperture  76  may be in fluid communication with the exterior  68  of the pouch  50  or, for example, may be covered by an additional layer (not shown) to protect or to hide the aperture  74  or  76 . The aperture  74  or  76  that is in fluid communication with the exterior  68  of the pouch  50  may be a slit or a hole or opening of any cross section, for example, circular, square-shaped, triangular, rectangular, pentagonal, or any other suitable shape. 
     Referring next to  FIGS. 6 and 7 , in a further embodiment, the first and second layers  64  and  66 , the thermoplastic weld layer  80 , and the first sidewall  52  are further attached together by a surrounding thermal seal  92 . The surrounding thermal seal  92  may be a continuous seal as shown in  FIG. 6 , or may an intermittent spot seal  192  as shown in  FIGS. 6A, 6G, and 6H . The surrounding thermal seal  92  may optionally be disposed between only the first and second layers  64  and  66 . Alternatively, the first and second layer  64  and  66 , and the surrounding thermal seal  92 , surrounds the first aperture  74  and the second aperture  76 . The surrounding thermal seal  92  may be a heat seal, a seal formed by ultrasonic vibration, or a thermal seal formed by any thermal sealing method known in the art. Although shown as a circular seal in  FIGS. 6, 6A, 6G, and 6H , the surrounding thermal seal  92  may have any shape, for example, triangular, elliptical, square-shaped, pentagonal, hexagonal, etc. 
     Although the individual sealing spots that comprise the intermittent spot seals  178   a ,  178   b , and  192  are shown in  FIG. 6A  to be generally circular, the individual sealing spots may be, for example, circular, elliptical, square-shaped, triangular, rectangular, pentagonal, hexagonal, or other shapes. Referring to  FIGS. 6G and 6H , in some embodiments, the intermittent spot seal  192  may have an odd plurality of circular individual sealing spots  400 , for example, three, five, seven, nine, eleven, thirteen, fifteen, seventeen, or more, such that a substantially gastight seal can form between the layers joined by the intermittent spot seal  192 . In some cases, an odd number of the individual sealing spots  400  may inhibit the formation of a wrinkle (not shown) that spans the intermittent spot seal  192  between pairs of the individual sealing spots  400  that are aligned with one of the side edges  56   a - 56   c  of the pouch  50 . The number, size, and space of the circular individual sealing spots  400  may each be predetermined to minimize formation of wrinkles (not shown) within a perimeter of the intermittent spot seal  192  that may interfere with the formation of a substantially gastight seal in the intermediate sealing region  86  between the offset first and second apertures  74  and  76 . For example, the intermittent spot seal  192  may be configured such that the symmetric melt regions  284  surrounding the adjacent circular individual sealing spots  400  do not overlap. 
     In another embodiment, the intermittent spot seal  192  may be comprised of an odd plurality of triangular individual sealing spots  402 , as illustrated in  FIG. 6H . The number, size, and spacing of the triangular individual sealing spots  402  may also each be predetermined to minimize formation of wrinkles (not shown) within a perimeter of the intermittent spot seal  192 . For example, the intermittent spot seal  192  may be configured such that the asymmetric melt regions  291  surrounding the adjacent triangular individual sealing spots  402  do not overlap, and further, such that the corner regions  291   a  of the asymmetric melt regions  291  point toward a central portion within the intermittent spot seal  192 .  FIG. 6H  further illustrates that the intermittent spot seals  178   a  and  178   b  may be comprised of individual sealing spots  404  that have a different shape than the triangular individual sealing spots  402 , for example, rectangular, as shown. 
     In yet another embodiment, as seen in  FIG. 8 , first edges  94   a  and  94  of the first and second layers  64  and  66 , respectively, are attached to the first sidewall  52  by a first edge thermoplastic weld layer  96 , and second edges  98   a  and  98  of the first and second layers  64  and  66 , respectively, are attached to the first sidewall  52  by a second edge thermoplastic weld layer  100 . Alternatively, as seen in  FIG. 8A , the first edges  94   a  and  94  of the first and second layer  64  and  66 , respectively, are attached to the first sidewall  52  by the intermittent spot seal  178   a , and the second edges  98   a  and  98  of the first and second layers  64  and  66 , respectively, are attached to the first sidewall  52  by the intermittent spot seal  178   b . Illustratively, the first and second edge thermoplastic weld layers  96 ,  100  and the intermittent spot seals  178   a ,  178   b  are disposed across the full width  62  ( FIG. 1 ) of the first sidewall  52 . The first and second layers  64  and  66  and the first and second edge thermoplastic weld layers  96 ,  100  or the intermittent spot seals  178   a ,  178   b  may, alternatively, be disposed across a portion of the first sidewall  52 , or on the interior  58  of the pouch  50 . 
     A still further embodiment is depicted in  FIG. 9 , wherein the entire second layer  66  is sealed directly to the first sidewall  52 . The first edge  94   a  of the first layer  64  is attached to the first sidewall  52  by the first edge thermoplastic weld layer  96 , and the second edge  98   a  of the first layer  64  is attached to the first sidewall  52  by the second edge thermoplastic weld layer  100 . Alternatively, as depicted in  FIG. 9A , the first edge  94   a  of the first layer  64  is attached to the first sidewall  52  by the intermittent spot seal  178   a , and the second edge  98   a  of the first layer  64  is attached to the first sidewall  52  by the intermittent spot seal  178   b . The first and second layers  64  and  66  and the first and second edge thermoplastic weld layers  96 ,  100  or the intermittent spot seals  178   a ,  178   b  may alternatively be disposed on the interior  58  of the pouch  50 . 
     Referring next to  FIG. 10 , in still another embodiment, a first plurality of apertures  102  extends through the first layer  64 . A second plurality of apertures  104  extends through the second layer  66 , wherein the second plurality of apertures  104  is offset from the first plurality of apertures  102 . A third plurality of apertures  106  extends through the first sidewall  52  of the pouch  50 . The second and third pluralities of apertures  104  and  106  are arranged to be coincident along a line perpendicular to the first sidewall  52 , thereby allowing fluid communication of the second plurality of apertures  104  with the interior  58  of the pouch  50 . Alternatively, the first and second layers  64  and  66  may be disposed on the interior  58  of the pouch  50 . 
     In a yet further embodiment, as seen in  FIGS. 11 and 12 , the second layer  66  includes an overlap region  170  that overlaps the first sidewall  52  and a portion  108  that does not overlap with the first sidewall. The projection  172  of the overlap region  170  of the second layer  66  is shown by the area outlined by the dashed line in  FIG. 11 . An edge  294  of the second layer  66  is joined to a closure flange  110  that may have a first closure element  200  disposed thereon, leaving a gap  112  across the full width  62  of the pouch  50  between the first sidewall  52  and the closure flange. A second closure element  202  may also be disposed on the second sidewall  54  opposing the first closure element  200 . The closure elements  200  and  202  may be any type of complementary interlocking closure elements known in the art, as previously described herein. The second plurality of apertures  104  is in fluid communication with the interior  58  of the pouch  50  through the gap  112 . The gap  112  is sealed along first and second ends  114  and  116  between the first layer  64  and the second sidewall  54 . The first and second edge thermoplastic weld layers  96  and  100  extend partially under the second layer  66  to attach the first and second layers  64  and  66  together and to attach the first and second layers to the first sidewall  52  and the closure flange  110 , respectively. In place of the thermoplastic weld layers  96 ,  100 , the intermittent spot seals  178   a ,  178   b  may attach the first and second layers  64  and  66  together and attach the first and second layers to the first sidewall  52  and the closure flange  110 , respectively. Alternatively, the first and second layers  64  and  66  and the first and second edge thermoplastic weld layers  96 ,  100  or the intermittent spot seals  178   a ,  178   b  may be disposed on the interior  58  of the pouch  50 . 
     The first and second layers  64  and  66  of any of the valves  40  as disclosed herein may be independently composed of any thermoplastic material, such as would be used for the first and second sidewalls  52  and  54  of the pouch  50  as described herein. Each of the first and second layers  64  and  66  may be composed of the same material as the other layer or could be independently composed of different material than that of the other layer. In addition, each of the first and second layers  64  and  66  may also have multiple plies, each ply being independently composed of any thermoplastic material, such as would be used for the first and second sidewalls  52  and  54  of the pouch  50  as described herein, or a blend of any thermoplastic material, such as would be used for the first and second sidewalls of the pouch as described herein. Illustratively, the first and second layers  64  and  66  may, for example, be composed of a polyolefin plastomer, such as an AFFINITY™ resin manufactured by Dow Plastics. 
       FIGS. 13-15  depict various illustrative embodiments for the first and second layers  64  and  66 . Referring to  FIG. 13 , the first layer  64  is composed of a first ply  118  and a second ply  120 . Although any suitable flexible thermoplastic materials may be used for the first and second plies  118  and  120 , in this embodiment, for example, the first ply  118  is composed of polypropylene or HDPE and the second ply  120  is composed of a polyolefin plastomer. The second layer  66  in  FIG. 13  includes a single ply and may be made of any suitable flexible thermoplastic, but illustratively, the second layer  66  is made of polypropylene, HDPE, polyolefin plastomer, or a blend of any two or all three of polypropylene, HDPE, and polyolefin plastomer. The structures of the first and second layers  64  and  66  may also be reversed such that the first layer  64  has a single ply and the second layer  66  has two plies. Other additives known to those skilled in the art may also be included in the composition of the first and second layers  64  and  66 , as desired, such as to improve handling and manufacturing characteristics. 
     As seen in  FIG. 14 , the first layer is substantially identical to that shown in  FIG. 13 , and the second layer  66  is composed of a first ply  122  and a second ply  124 . Although any suitable flexible thermoplastic materials may be used for the first and second plies  122  and  124  of the second layer  66 , in this embodiment, for example, the first ply  122  is composed of a polyolefin plastomer and the second ply  124  is composed of polypropylene or HDPE. 
     Referring next to  FIG. 15 , the first and second layers  64  and  66  are both composed of a single ply of material. Although any suitable flexible thermoplastic materials may be used for the first and second layers  64  and  66 , illustrative materials are polyolefin plastomer, polypropylene, HDPE, or a blend of any two or all three of polypropylene, HDPE, and polyolefin plastomer. 
     Although not shown, it is also contemplated that one or more of the valves  40  or valve layers, for example, the first and second layers  64  and  66 , may extend along a portion of the width  62  of the pouch  50 . For example, one or more of the valve layers may extend only along a portion of the pouch  50  proximate to one side edge of the pouch, or may be disposed away from the side edges of the pouch toward the center of the pouch, or may be offset from the center of the pouch. However, by extending the valve  40  across the entire width  62  of the pouch  50 , it is contemplated that the complexity of manufacturing the valve and/or pouch may be reduced, because the first and second layers  64  and  66  may be applied in a continuous process. 
     Referring next to  FIGS. 16 and 17A , a container  300  having a container lid  302  that includes a valve  340  and that sealingly fits on a hard-walled container body  304  is illustrated. A container useful herein includes those disclosed in, for example, Zettle et al. U.S. Pat. No. 6,032,827 or Stanos et al. U.S. Pat. No. 7,063,231. A sealing layer  306  may be applied to an inner surface  308  of a peripheral rim  310  of the lid  302  to assist in achieving a gastight seal therebetween. A second sealing layer  306   a  of the same or a different sealing material may also be applied to a surface  312  of a peripheral lip  314  of the container body  304 . Any suitable sealing material known to those skilled in the art may be used, including, for example, one or more polyolefin plastomers, including, for example, an AFFINITY™ resin manufactured by Dow Plastics. The container body  304  may have rigid sidewalls  316  to support a variety of contents  318 , for example, fresh vegetables or other perishable foodstuffs, and may be made of any suitable material known to those skilled in the art, including, for example, a thermoplastic resin. 
     In this embodiment, a first layer  364  is disposed over an opening  320  defined by an inner annular flange  368  of the lid  302 . A second layer  366  is also disposed over the opening  320 . A first aperture  374  extends through the second layer  366 , and a second aperture  376  is offset from the first aperture  374  and extends through the first layer  364 . Illustratively, a peripheral thermoplastic weld layer  396  extends partially under the first layer  364  to weld the first and second layers  364  and  366  together, and to weld the first and second layers to the inwardly projecting annular flange  368 . The annular flange  368  has an extension  370  that further extends from the annular flange toward the opening  320 . A third aperture  378  extends through the peripheral thermoplastic weld layer  396 , and a fourth aperture  380  extends through the flange extension  370 . The second, third, and fourth apertures  376 ,  378 , and  380  are aligned along a line perpendicular to the flange extension  370 , such that the second aperture  376  is in fluid communication with an interior  322  of the container body  304  when the lid  302  is applied thereto. 
     Referring to  FIG. 17B , another embodiment of the lid  302  is illustrated having an elastomeric film layer  324  that spans the opening  320  defined by the annular flange  368  of the lid  302 . The film layer  324  is made of a flexible thermoplastic material, for example, polyolefin plastomer, polypropylene, HDPE, or a blend of any two or all three of polypropylene, HDPE, and polyolefin plastomer. The film layer  324  is attached to the annular flange and the flange extension  370  by any suitable method known in the art, for example, by ultrasonic or thermal welding, by application of an adhesive, or by a thermoplastic weld layer  396   a.    
     This embodiment is similar to the embodiment discussed in regards to  FIG. 17A , except for the differences described in the following. The first layer  364  and the second layer  366  are disposed only over the extent of the flange extension  370 . A fifth aperture  382  extends through the film layer  324  and is aligned with the second, third, and fourth apertures  376 ,  378 , and  380  along a line perpendicular to the flange extension  370 , such that the second aperture  376  is in fluid communication with the interior  322  of the container body  304  when the lid  302  is applied thereto. The first and second layers  364  and  366  may be applied to the film layer  324  over the flange extension  370  by any suitable method known in the art, for example, by a surrounding seal  392  that surrounds the first and second apertures  374  and  376 . The surrounding seal  392  may be a continuous seal or may be an intermittent spot seal, as discussed previously for another embodiment herein regarding the surrounding seal  92 . 
     Further, it is also contemplated that any of the valves described herein, for example, the valve  340 , may be constructed independently of the container  300  and applied to the container, such as to the pouch  50 , the container lid  302 , or the container body  304 , after or during the manufacturing thereof. One such embodiment is illustrated in  FIGS. 18 and 19 , wherein the valve  340  is applied to the container body  304  using an adhesive layer  384 . In this embodiment, the film layer  324  of the lid  302  spans the opening  320  and includes no apertures therethrough. Although the adhesive layer  384  is shown to attach the valve  340  to the container body  304 , either of the first and second layers  364  and  366  may be, alternatively, or in addition to, attached to the sidewall  316  by any suitable method known in the art, for example, directly by a thermoplastic weld layer  396   b . The first aperture  374  extends through the second layer  366  and is offset from the second aperture  376  that extends through the first layer  364 . The third aperture  378  extends through the thermoplastic weld layer  396   b  and a fourth aperture  380   a  extends through the sidewall  316 . A fifth aperture  382   a  extends through the adhesive layer  384 . The second, third, fourth, and fifth apertures  376 ,  378 ,  380   a , and  382   a  are aligned along a line perpendicular to the sidewall  316 , such that the second aperture  376  is in fluid communication with the interior  322  of the container body  304 . Further, it is believed that the embodiments shown in  FIGS. 16-19  operate in a fashion similar to the valves  40  described above. Illustratively, after the contents  318  are placed into the container body  304  and the lid  302  is applied thereto, a source of vacuum pressure (not shown) is applied over the first and second apertures  374  and  376 . The flange extension  370  or the sidewall  316  provides a support surface for application of the source of vacuum pressure. As gas is removed from the container body  304 , the flexible material of the first and second layers  364  and  366  or the film layer  324  are compressed into the container body by atmospheric pressure. The first and second layers  364  and  366  or the film layer  324  cover and conform to the contents  318 , as the gas is removed from the container body  304 . The first and second layers  364  and  366  or the film layer  324  may be attached to the peripheral flange  368  by any suitable method known in the art, for example, by ultrasonic or thermal welding, or by application of an adhesive. 
     Another embodiment of a valve that may be constructed independently of the container  300  as a valve strip  440  and applied to the container, such as to the pouch  50 , the container lid  302 , and/or the container body  304 , after or during the manufacturing thereof is illustratively shown in  FIGS. 20 and 21 . A first layer  464  of a film material is disposed over a second layer  466  of the film material. Each of the first and second layers  464  and  466  may be comprised of one or more plies of material as described above with regard to the first and second layers  64 ,  66 . The first and second layers  464  and  466  are attached to each other, for example, by a thermal seal  478  around the periphery  480  of the first layer  464 . The thermal seal  478  may be continuous (not shown), or may be an intermittent spot seal comprising individual sealing spots  482  of any convenient shape, preferably, triangular, as illustrated in  FIG. 20 . The thermal seal  478  may be a heat seal, a seal created by ultrasonic vibration, or some other thermal seal as is known in the art. 
     A first aperture  474  extends through the first layer  464  and a second aperture  476  extends through the second layer  466 . A surrounding thermal seal  492  that connects the first and second layers  464  and  466  surrounds the first aperture  474  and the second aperture  476 . The surrounding thermal seal  492  may be a heat seal, a seal formed by ultrasonic vibration, or a thermal seal formed by any thermal sealing method known in the art. Although shown as circular in  FIG. 20 , the surrounding thermal seal  492  may be any shape, for example, triangular, elliptical, square-shaped, pentagonal, hexagonal, etc. Also, the surrounding thermal seal  492  may be continuous (not shown), or may an intermittent spot seal comprising individual sealing spots  496  of any convenient shape, preferably, triangular, as illustrated in  FIG. 20 . Further, the surrounding thermal seal  492  may be comprised of any number of individual sealing spots  496 , for example, fifteen, as illustrated in  FIG. 20 . The number, size, shape, and spacing of the individual sealing spots  496  may also each be selected to minimize formation of wrinkles (not shown) within a perimeter of the surrounding thermal seal  492 , for example, as described above. 
     A third aperture  484  extends through an exterior wall of the container  300 , such as the first sidewall  52 , the lid  302 , or the container sidewall  316 . The second layer  466  has an attachment surface  468  that is adapted to be attached facing the third aperture  484 . At least a portion of the attachment surface  468  may also be embossed or otherwise textured with a pattern  486  to define a region of flow channels  488 . The valve strip  440  may have a means for attachment  490 , for example, a strip or layer or thermoplastic weld material, a direct thermal seal, or an adhesive disposed around the periphery  494  of the attachment surface  468 . The means of attachment  490  may be coincident with or one and the same as the thermal seal  478 . 
     In use, the valve strip  440  is placed over the third aperture  484  to create an evacuable container that can be evacuated by a user through the region of flow channels  488  defined between, for example, the attachment surface  468  and the first sidewall  52 , the lid  302 , or the container sidewall  316 . The valve strip  440  may have any convenient shape, for example, including rectangular, circular, elliptical, star shaped, or as desired to match a seating surface of an evacuation source (not shown) that may be applied to the container  300  or the pouch  50 . 
     In another embodiment of a valve strip  442 , as illustrated in  FIGS. 22 and 23 , a region on a surface of the second layer  466  that faces the first layer  464  and that is disposed between the first and second apertures  474 ,  476  and bounded by the second aperture  476  may also be embossed or otherwise textured with a pattern  465  to define a region of flow channels  467 . In a further embodiment, not shown, a region on a surface of the first layer  464  that faces the second layer  466  and that is disposed between the first and second apertures  474 ,  476  and at least partially overlapping the second aperture  476  may also be embossed or otherwise textured with the pattern  465  to define the region of flow channels  467 . In these embodiments, the first and second layers  464  and  466  are in direct contact in an intermediate seal region  487  between the first aperture  474  and the region of flow channels  467 , which is in fluid communication with the third aperture  484  via the second aperture  476  and the region of flow channels  488 . In use, application of vacuum pressure over the exterior of the first aperture  474  and a portion of the region of flow channels  467  causes gas resident within the region of flow channels  467  to have a greater pressure than the exterior allowing gas to flow therethrough. 
     It is further contemplated that any of the embodiments of the valve strip  440 ,  442  may be provided as a component of a kit or a package that comprises a tool, for example, a hole punch, for creating an aperture in a wall of a container, and/or a vacuum pump to evacuate gas from the interior of the container through the aperture via the valve strip applied over the aperture. In this, or in any of the embodiments shown, the valve  40 ,  340 , or valve strip  440 ,  442  may be adhered to the pouch  50  or to the container lid  302 , film layer  324 , or container body  304 , as described herein, or by an adhesive known to those skilled in the art, such as described in Engel et al. U.S. Pat. No. 7,178,555 or Hartman et al. U.S. Patent Application Publication No. 2006/0030472, now U.S. Pat. No. 7,244,223. Further, it is contemplated that a variety of containers are suitable for application of the valves  40 ,  340 , or  440  herein described, including, for example, pouches, bowls, bottles, Ziploc® containers, storage boxes, canisters, or other containers, and any lids or covers that may be attachable thereto. 
     INDUSTRIAL APPLICABILITY 
     A container is presented that includes a valve to evacuate gas from the container. The valve may include first and second layers of film material that form a substantially gastight seal therebetween upon direct contact of the layers. An intermittent spot seal may attach the first and second layers of film material. A first aperture through the first layer is offset from a second aperture through the second layer. Vacuum pressure disposed over both of the first and second apertures, for example, causes the first layer to separate from the second layer to allow gas to exhaust from the container. 
     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 to use the invention, and to teach the best mode of carrying out the same. The exclusive rights to all modifications that 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.