Patent Publication Number: US-8529129-B2

Title: Closure element for a pouch

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     REFERENCE REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     SEQUENTIAL LISTING 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates generally to closure mechanisms, and particularly, to a closure mechanism that includes a valve structure that may be used on a container, such as a pouch. 
     2. Description of the Background of the Invention 
     Food is or other perishables are often stored in containers such as thermoplastic pouches. A thermoplastic pouch having a resealable closure mechanism extending along an opening into an interior thereof may be repeatedly opened and closed. In order to keep the food stored inside the pouch fresh for an extended period, a user may expel excess air out of the pouch before completely sealing the closure mechanism. Some pouches allow a vacuum to be formed inside the pouch and then be sealed so as to vacuum pack the contents of the pouch. Other pouches have been developed that have a separate air evacuation route so that air may be removed from the pouch after the closure mechanism has already been sealed. 
     One closure mechanism on a pouch has a directional exhaust aperture through the closure mechanism. The closure mechanism has a first closure element attached to one pouch wall and a second closure element attached to a second pouch wall opposite to the first pouch wall. The first closure element has a first base portion and a female closure profile extending from the first base. The second closure element has a second base portion and a male closure profile extending from the second base. The female profile interlocks with the male profile in a closed position. A cantilevered valve flange extends from the first base toward the second base. The flange is spaced from the male and female closure profiles on a product side of the closure mechanism. An aperture through the first base is disposed between the female profile and the cantilevered valve flange. The cantilevered valve flange is biased in sealing engagement against the second base in the closed position to prevent air from entering the pouch through the aperture. In response to higher relative pressure from within the pouch, the valve flange separates from the second base and allows air to escape through the aperture. 
     Other closure mechanisms on pouches have a reclosable seal having opposing closure elements and a bidirectional vent. In one embodiment, the vent has an aperture through a fin extending downwardly from one of the closure elements. A portion of a pouch wall extends loosely above the aperture to prevent insects from entering the pouch through the aperture. A tamper evident partition extends between the two closure elements. In another embodiment, the pouch wall extends above the aperture on an inner side of the fin, and a tamper evident partition extends between the pouch wall and an opposing bag wall. In yet another embodiment, the aperture is through the pouch wall, and the fin extends below the aperture. 
     Another closure mechanism on a pouch has opposing front and back pouch walls, the closure mechanism sealingly mounted to the front wall, and a one-way vent through the front pouch wall adjacent to the closure mechanism. The closure mechanism is disposed on an interior portion of the front pouch wall, and a frangible portion of the front pouch wall provides access to the closure mechanism for operating the mechanism. A gap in the seal mount of the closure mechanism, an aperture through the front pouch wall within the seal mount, and a flap between the gap and the aperture form a vent from an interior of the pouch through the front pouch wall. The flap allows air to exit the interior of the pouch and prevents air from entering the interior of the pouch through the vent. 
     Still another closure mechanism on a pouch has an exhaust vent in a side wall of the pouch. The vent has a backing member extending from a closure element along an interior side of a pouch wall and an aperture through the pouch wall. The aperture is disposed opposite to the backing member such that the backing member covers the aperture. The pouch wall is sealed to the backing member around a portion of the aperture defining a passageway through which air may pass at an unsealed portion. The unsealed portion of the pouch wall allows air to escape out of the pouch through the aperture and prevents air from entering the pouch through the aperture. 
     Yet another closure mechanism on a pouch has a first closure element having a female profile extending from a base with a first pouch sidewall extending therefrom. Apertures through the base of the female profile provide communication between a space between first and second female legs that extend from the base and an opposite side of the base so that a male profile inserted into the female profile will urge any particles lodged in the space to pass through the apertures, out of the closure mechanism, and back into an interior of the pouch. 
     SUMMARY OF THE DISCLOSURE 
     According to one aspect of the disclosure, a closure mechanism for a pouch comprises a first interlocking closure element and a second interlocking closure element. A first closure profile is disposed on an interior side of the first interlocking closure element. A flange extends from the first closure profile and a first aperture is disposed therethrough. A resilient valve flap covers the first aperture and is attached to an exterior side of the flange. A channel is defined between the resilient valve flap and the flange that extends from the first aperture to an edge of the resilient valve flap. The resilient valve flap is biased to form a releasable airtight seal against the exterior side of the flange across the channel. 
     According to another aspect of the disclosure, a closure element for a pouch comprises a closure profile and a flange that extends from the closure profile and has a first aperture disposed therethrough. The flange has first and second opposite sides and the closure profile is arranged on a first side of the flange. A resilient valve flap covers the first aperture and is attached to the flange. A channel is defined between the resilient valve flap and the flange that extends from the aperture to an edge of the resilient valve flap. The resilient valve flap is biased to form an airtight seal against the second side of the flange across the channel. 
     According to yet another aspect of the disclosure, a resealable valve comprises a flange extending from a closure element and including an aperture disposed therethrough and in fluid communication with an interior side of the closure element. The aperture extends through the flange from the interior side of the flange. A resilient valve flap covers the aperture on the exterior side of the flange and is attached to the exterior side of the flange. A channel is defined between the resilient valve flap and the flange that extends from the aperture to an edge of the resilient valve flap. The resilient valve flap is biased to form a releasable airtight seal against the exterior side of the flange across the channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a reclosable pouch; 
         FIG. 2  is an isometric view of an embodiment of a first closure element; 
         FIG. 3  is a plan view of the embodiment of  FIG. 2 ; 
         FIG. 3A  is a cross-sectional view of the embodiment of  FIG. 2  in a sealed state taken generally along the lines  3 A- 3 A of  FIG. 2  and  FIG. 3 ; 
         FIG. 4  is a cross-sectional view of the embodiment of  FIG. 2  in an unsealed state taken generally along the lines  3 A- 3 A of  FIG. 2  and  FIG. 3 ; 
         FIG. 5  is a fragmentary cross-sectional view of the embodiment of  FIG. 2  attached to a pouch that has an attached textured wall taken generally along the lines  5 - 5  of  FIG. 1  with portions behind the plane of the cross section omitted for clarity; 
         FIG. 6  is a fragmentary cross-sectional view of the embodiment of  FIG. 2  attached to a pouch that has a textured second sidewall taken generally along the lines  5 - 5  of  FIG. 1  with portions behind the plane of the cross section omitted for clarity; 
         FIG. 7  is an isometric view of another embodiment of a first closure element in a sealed state; 
         FIG. 8  is an isometric view of the embodiment of  FIG. 7  in an unsealed state; 
         FIG. 9  is a cross-sectional view of the embodiment of  FIG. 7  in a sealed state taken generally along the lines  9 - 9  of  FIG. 7 ; 
         FIG. 10  is a cross-sectional view of the embodiment of  FIG. 7  in an unsealed state taken generally along the lines  10 - 10  of  FIG. 8 ; and 
         FIG. 10A  is a cross-sectional view of yet another embodiment of a first closure element in an unsealed state taken generally along the lines  10 - 10  of  FIG. 8 . 
     
    
    
     Other aspects and advantages of the present disclosure will become apparent upon consideration of the following detailed description, wherein similar structures have similar reference numerals. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a reclosable thermoplastic pouch  50  includes first and second pouch sidewalls  52  and  54  joined around three edges  56   a - 56   c  by heat sealing, or another sealing method known in the art, to define a primary opening  57 . Alternatively, the bottom edge  56   b  may be a fold line between the first and second side walls  52  and  54 . A closure mechanism  58  is attached to inner surfaces  60  and  62  of the first and second sidewalls  52  and  54 , respectively, proximate to the primary opening  57 . The closure mechanism  58  and the first and second sidewalls  52  and  54  define a pouch interior  64 . The closure mechanism  58  allows the pouch  50  to be repeatedly opened and closed. When occluded, the closure mechanism  58  provides an airtight seal such that a vacuum may be maintained in the pouch interior  64  for a desired period of time, such as days, months, or years, when the closure mechanism is sealed fully across the primary opening  57 . The closure mechanism  58  comprises first and second complementary interlocking closure elements  70 ,  72  that are attached, respectively, to the inner surfaces  60  and  62  of the first and second sidewalls  52  and  54 . 
     A secondary opening  67   a ,  67   b , allows fluid communication between the interior  64  and an exterior  66  of the pouch  50 . The secondary opening  67   a  may extend through either the first or second sidewall  52 ,  54 . The secondary opening  67   b  may extend through a side edge  56   a - 56   c , for example, through the bottom edge  56   b . One or more valves  68   a ,  68   b  may optionally be disposed in or covering each respective secondary opening  67   a ,  67   b  to allow air to be evacuated from the pouch interior  64  and/or to maintain a vacuum when the closure mechanism  58  has been sealed. As shown in  FIG. 1 , the valves  68   a ,  68   b  may, for example, be disposed on the first sidewall  52  spaced from the closure mechanism  58 . The valve  68   a ,  68   b  provides a fluid path with fluid communication between the pouch interior  64  and the exterior  66  of the pouch. Illustrative valves useful in the present disclosure include those disclosed in, for example, Newrones et al. U.S. Patent Application Publication No. 2006/0228057, Buchman U.S. Patent Application Publication No. 2007/0172157, and Tilman et al. U.S. Patent Application Publication No. 2007/0154118. Other valves useful in the present disclosure include those disclosed in, for example, U.S. patent application Ser. No. 11/818,586, now U.S. Pat. No. 7,946,766, No. 11/818,591, now U.S. Pat. No. 7,874,731, and No. 11/818,592, now U.S. Pat. No. 7,967,509, each filed on Jun. 15, 2007. 
     The first complementary interlocking closure element  70  includes a first closure profile  70   a  and a first flange  70   b  extending from the first closure profile. The second complementary interlocking closure element  72  includes a second closure profile  72   a  and may include a second flange  72   b  extending from the second closure profile. In one embodiment, the first closure profile  70   a  has a first flange  70   b  extending from an edge  70   c  thereof, as shown in  FIGS. 2-4 . The first flange  70   b  includes an interior side  78  and an exterior side  80 . A first aperture  82 , as seen in  FIGS. 3-4 , is disposed through the first flange  70   b  to provide fluid communication between the interior side  78  and the exterior side  80  of the first flange. Although the first aperture  82  is illustrated, for example, in  FIG. 3  to be circular, the first aperture may have any convenient shape such as elliptical, triangular, square-shaped, pentagonal, hexagonal, or other shapes. A plurality of first apertures  82  may be distributed along a partial length of the closure mechanism  58 , or along the entire length of the closure mechanism, as shown in  FIG. 1 . 
       FIGS. 3A and 4  depict the resilient valve flap  86  in a sealed state and an open state, respectively. As best seen in  FIG. 3A , a raised lip  84  may extend from the exterior side  80  of the flange  70   b  around a periphery of the first aperture  82 . A resilient valve flap  86  that covers the first aperture  82  is sealed to the exterior side  80  of the first flange  70   b . The resilient valve flap  86  may be sealed against the exterior side  80  of the first flange  70   b  by a sealing layer  286 , as shown in  FIGS. 2-6 . The sealing layer  286  may utilize any sealing method known in the art, for example, a heat seal, an adhesive, or a thermoplastic weld layer. The raised lip  82  displaces the resilient valve flap  86  away from the exterior side  80  of the first flange  70   b . This displacement  88 , best seen in  FIG. 3A , biases the resilient valve flap  86  to form a releasable seal against the raised lip  84 . As best seen in  FIG. 4 , a channel  90  is defined between the resilient valve flap  86  and the exterior side  80  of the first flange  70   b  where the resilient valve flap and the exterior side are not sealed to one another. The channel  90  extends from the first aperture  82  to an edge  92  of the resilient valve flap  86 . 
     In this embodiment, the resilient valve flap  86  may function as a one-way check valve. For example, the pouch  50  may have the closure mechanism  58  occluded with a positive pressure difference across the resilient valve flap  86  from the exterior  66  to the interior  64  of the pouch, wherein the positive pressure difference allows the resilient valve flap to remain in a biased sealed position, as shown in  FIG. 3A . However, a positive pressure difference across the resilient valve flap  86  from the interior  64  to the exterior  66  may cause the resilient valve flap to separate from the raised lip  84  if the positive pressure difference is greater than a threshold level required to overcome the sealing bias of the resilient valve flap, as shown in  FIG. 4 . 
       FIG. 4  illustrates the resilient valve flap  86  that has separated from the raised lip  84  under a sufficient positive pressure difference. The channel  90  provides a fluid path, as indicated by the curved arrow  94 , for fluid such as air to escape from the interior  64  to the exterior  66  of the pouch  50 . Upon a decrease of the positive pressure difference to below the threshold level required to overcome the sealing bias of the resilient valve flap  86 , the resilient valve flap returns to a sealing position as shown in  FIG. 3A . 
     The first complementary interlocking closure element  70  may also include a third profile  96  that extends from the interior side  78  of the first flange  70   b . As shown in  FIGS. 2-6 , the third profile  96  may be hollow or have a second aperture  98  therethrough. The third profile  96  may make contact with the inner surface  62  of the second sidewall  54  when the closure mechanism  58  is occluded, and inhibits and/or prevents the inner surface from blocking the first aperture  82 , thereby providing a fluid path from the interior  64  of the pouch  50  through the aperture  82 , as depicted by the curved arrow  94 . As shown in  FIG. 1 , the pouch  50  may also include a relief such as embossing or texturing on or along an interior surface of one or both of the first and second sidewalls  52 ,  54  to provide fluid or air flow channels  74  between the sidewalls when fluid is being evacuated from the pouch  50 , or when a vacuum, for example, is being drawn through the valve  68   a ,  68   b  or through the first complementary interlocking closure element  70 . In this manner, the pouch  50  provides an evacuable system within which items, for example, food, may be stored. One or both sidewalls, such as the second sidewall  54 , may also be embossed or otherwise textured  76  with a pattern, such as, for example, the diamond pattern shown in  FIG. 1 , to provide the air flow channels  74  on one or both surfaces spaced between the bottom edge  56   b  and the second closure profile  72   a . Alternatively, a separate textured and embossed patterned wall  176 , as shown in  FIG. 5 , may be used to provide additional flow channels (not shown) within the pouch interior  64 , wherein the pattern extends from just beneath the second closure profile  72   a  to the bottom edge  56   b  and opposes the third closure profile to provide fluid communication between the interior  64  of the pouch  50  and the second aperture  98 . Illustrative flow channels useful in the present disclosure include those disclosed in Zimmerman et al. U.S. Patent Application Publication No. 2005/0286808, Buchman U.S. Patent Application Publication No. 2007/0172157, and Tilman et al. U.S. Patent Application Publication Nos. 2006/0048483 and 2007/0154118. Other flow channels useful in the present disclosure 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. 
     The first complementary interlocking closure element  70  may be attached to the inner surface  60  of the first sidewall  52 , or may illustratively be attached to an outer surface  100  of the first pouch wall  52 , as shown in  FIG. 5 . Similarly, the second complementary interlocking closure element  72  may be attached to an outer surface  102  of the second pouch wall  54 , or may illustratively be attached to the inner surface  62  of the second pouch wall, as shown in  FIG. 5 . It is contemplated further that the second complementary interlocking closure element  72  may comprise only the second closure profile  72   a  that is attached to the inner surface  62  of the second sidewall, as shown in  FIG. 6 . The textured  76  pattern can be seen in  FIG. 6  on the inner surface of the second sidewall  54  and opposing the third profile  96 . 
     The first and second closure profiles  70   a ,  72   a  may be generally hooked closure profiles, respectively, as shown in  FIGS. 2-6 . However, the configuration and geometry of the closure profiles  70   a ,  72   a  or closure elements  70 ,  72  disclosed herein may vary. 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 closure profiles  70   a ,  72   a  or closure elements  70 ,  72  to fill in any gaps or spaces therein when occluded. The ends of the interlocking profiles  70   a ,  72   a  or closure elements  70 ,  72  may also be welded or sealed by ultrasonic vibrations as is known in the art. 
     In a further embodiment (not shown), one or both of the first and second closure elements  70 ,  72  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  70   a ,  72   a  in order to provide a tactile sensation, such as a series of clicks, as a user draws the fingers along the closure mechanism  58  to seal the closure elements across the primary opening  57 . In addition, protuberances, for example, ridges (not shown), may be disposed on the inner surfaces  60 ,  62  of the respective first and second sidewalls  52 ,  54  proximate to the primary opening  57 , 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 . 
     Illustrative interlocking profiles, closure elements, sealing materials, tactile or audible closure elements, and/or end seals useful in the present disclosure 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 disclosure 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, and U.S. patent application Ser. No. 11/818,585, now U.S. Pat. No. 7,857,515, No. 11/818,586, now U.S. Pat. No. 7,946,766, and No. 11/818,593, now U.S. Pat. No. 7,784,160, each filed on Jun. 15, 2007. 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. It is also contemplated that a pouch useful herein may also be closed by other methods known to those skilled in the art other than, or in conjunction with, interlocking profiles, including, for example, heat sealing as disclosed in, for example, Bassett et al. U.S. Patent Application Publication No. 2007/0155607. 
     Referring to  FIGS. 7-10 , in another embodiment, a first complementary interlocking closure element  170  is similar to the first closure element  70 , but includes the following differences. A resilient valve flap  186  includes a sealing member  188  and an at least partially elastomeric latch  146 . The sealing member  188  includes a flap wall  120  and a hinged gate  124 . The flap wall  120  extends from the exterior side  80  of the first flange  70   b , and the hinged gate  124  extends from a distal end of the flap wall. The hinged gate  124  has an exterior side  126  and an interior side  128 . A hinge  122  may be disposed in the flap wall  120  or in the hinged gate  124  or at a point where the flap wall is connected to the hinged gate, as shown in  FIGS. 9 and 10 . The hinging action of the hinged gate  124  to the flap wall  120  may be facilitated by any method known in the art including, for example, by a weakened area in the flap wall or by thinning one or both of the flap wall and the hinged gate proximate to the hinge  122 . A first sealing wall  130  extends from the exterior side  80  of the first flange  70   b  and a second sealing wall  132  extends from the interior side  128  of the hinged gate  124 . In another embodiment, the sealing member  188  may comprise a hinged gate  124  that is attached to or extends from the first flange  70   b , as shown in  FIG. 10A . The hinge  122  may be disposed on the hinged gate  124  or at a point where the hinged gate is connected to the first flange  70   b , as shown in  FIG. 10A . 
     The at least partially elastomeric latch  146  includes a support wall  134  and an elastomeric strip  140 . The at least partially elastomeric latch  146  keeps the hinged gate  124  in a closed position, as shown in  FIGS. 7 and 9 . The support wall  134  extends from the exterior side  80  of the first flange  70   b  and includes a notch  136  disposed though the support wall proximate a distal end  138  thereof. The elastomeric strip  140  is sealed along a first edge  142  to the exterior side  126  of the hinged gate  124  and along a second edge  144  to the distal end  138  of the support wall  134 . The elastomeric strip  140  may be sealed to the hinged gate  124  and the support wall  134  by sealing layers  386  and  486 , respectively, as shown in  FIGS. 7-10A . The sealing layers  386  and  486  may utilize any sealing method known in the art including, for example, a heat seal, an adhesive, or a thermoplastic weld layer. In the closed position, the first sealing wall  130  engages and forms a releasable airtight seal with the second sealing wall  132 . The hinged gate  124  is biased by the at least partially elastomeric latch  146  to form a releasable airtight seal between the first and second sealing walls  130 ,  132 . 
     In this embodiment, the hinged gate  124  and the at least partially elastomeric latch  146  may function together as a one-way check valve. For example, the pouch  50  may have the closure mechanism  58  occluded with a positive pressure difference across the hinged gate  124  from the exterior  66  to the interior  64  of the pouch  50 , wherein the positive pressure difference allows the hinged gate to remain in a biased sealed position, as shown in  FIGS. 7 and 9 . However, a positive pressure difference across the hinged gate  124  from the interior  64  to the exterior  66  may cause the hinged gate to outwardly pivot from the hinge  122  and to separate the first and second sealing walls  130 ,  132  if the positive pressure difference is greater than a threshold level required to overcome the sealing bias of the at least partially elastomeric latch  146 , as shown in  FIGS. 8 and 10 . 
       FIGS. 8 and 10  illustrate the hinged gate  124  that has outwardly pivoted under a sufficient positive pressure difference to separate the first and second sealing walls  130 ,  132 . The notch  136  provides a fluid path, as indicated by the curved arrow  194 , for fluid to escape from the interior  64  to the exterior  66  of the pouch  50 . Upon a decrease of the positive pressure difference to below the threshold level required to overcome the sealing bias of the at least partially elastomeric latch  146 , the hinged wall  124  returns to a sealing position, as shown in  FIGS. 7 and 9 . Although not shown, it is contemplated that the at least partially elastomeric latch  146  may comprise only an elastomeric member that would be sealed along a first edge to the exterior side  126  of the hinged gate  124  and along a second edge to the exterior side  80  of the first flange  70   b . Such an entirely elastomeric latch may also include an aperture therethrough that would function as a fluid path for fluid to escape like the notch  136  in the at least partially elastomeric latch  146 . 
     An evacuation pump or device (not shown) may also be used to evacuate fluid from the pouch  50  through, for example, the valve  68   a ,  68   b  disposed in one of the side walls  52 ,  54 , or in or through one of the edges  56   a - 56   c , or through the closure mechanism  58 . An evacuation device may be placed over one or more of the apertures  82  to evacuate the pouch  50 . In the embodiment illustrated in  FIGS. 2-6 , the evacuation device may be placed over one or more of the plurality of apertures  82  to evacuate the pouch  50 . In the embodiments illustrated in  FIGS. 7-10A , the evacuation device covers the entire hinged gate  124  to evacuate the pouch  50 . Illustrative evacuation pumps or devices useful in the present disclosure include those disclosed in, for example, U.S. patent application Ser. No. 11/818,703, filed on Jun. 15, 2007, now U.S. Patent Application Publication No. 2008/0308177, and U.S. patent application Ser. No. 12/008,164, filed on Jan. 9, 2008, now U.S. Patent Application Publication No. 2009/0175747. 
     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. It is further contemplated that the resilient valve flap embodiments disclosed herein may also be used with containers other than thermoplastic pouches or bags similar to the valves disposed on hardwalled containers and lids, as shown in U.S. patent application Ser. No. 11/818,591, filed on Jun. 15, 2007, now U.S. Pat. No. 7,874,731. 
     In one embodiment, the first and second sidewalls  52 ,  54  and/or the closure mechanism  58  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  58  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  60 ,  62  of the respective sidewalls  52 ,  54  or a portion or area thereof, or portions or areas of the first flange  70   b , the resilient valve flap  86 , or the first and second sealing walls  130 ,  132  may, for example, be composed of an elastomer or 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  58  to provide an additional cohesive seal between the sidewalls  52 ,  54  when the pouch  50  is evacuated, or the portions or areas of the first and second sealing walls  130 ,  132  that engage one another to form an airtight seal therebetween, or the portions or areas of the resilient valve flap  86  and the raised lip  84  or the first flange  70   b  that form an airtight seal therebetween. 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  58  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  58  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 disclosure include those disclosed in, for example, Tilman et al. U.S. Patent Application Publication No. 2006/0048483. 
     INDUSTRIAL APPLICABILITY 
     A closure mechanism for a pouch is presented that includes a first interlocking closure element and a second interlocking closure element. A closure profile is disposed on an interior side of the first interlocking closure element. A flange extends from the closure profile and an aperture is disposed therethrough. A resilient valve flap is disposed over the aperture and attached to an exterior side of the flange. A channel is defined by an area of non-attachment of the resilient valve flap to the flange that extends from the aperture to an edge of the resilient valve flap. The resilient valve flap is biased to form a releasable airtight seal in the area of non-attachment of the resilient valve flap to the flange. The closure mechanism may be used with an evacuation device to expel excess air out of the pouch and to form a vacuum therein to keep food or other perishable contents stored inside the pouch fresh for an extended period of time. 
     Numerous modifications to the present disclosure 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 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.