Abstract:
The present invention is directed to a method and apparatus for accommodating the pressure decrease of the fluid in a hot-filled plastic container.

Description:
This application claims the benefit of pending Provisional Patent Application Ser. No. 61/105,241, filed Oct. 14, 2008 and pending Provisional Patent Application Ser. No. 61/020,633, filed Jan. 11, 2008, the entire disclosures of each application being incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to a closure for an associated container, and more specifically to a rotatable cap closure with one or more sealing features for creating a positive pressure or accommodating a pressure drop in a plastic container associated with the occurrence of a vacuum, thereby generally preventing the deformation of the container. 
     BACKGROUND OF THE INVENTION 
     Internally threaded, plastic cap closures have found widespread application for use in connection with hot-fill plastic containers by virtue of their low manufacturing costs and sealing performance. In a conventional hot-fill process, a hot beverage product is introduced into the plastic container, typically filling most of the container. The fluid is heated during a pasteurization or sterilization process to remove bacteria or other contamination. The plastic container is hermetically sealed with a cap while the product is still hot. Since the beverage product is typically not filled to the top of the container, a headspace of air is provided between the liquid enclosed within the plastic container and an inner surface of the cap. The temperature of the liquid varies from a high of about 185 degrees Fahrenheit, the typical hot-fill temperature, to about 40 degrees Fahrenheit, the typical refrigeration temperature. A change in temperature, from hot to cold, decreases the internal pressure of the sealed container and creates a vacuum within the container primarily as a result of the thermal contraction of the liquid in the container. This decrease in pressure can distort and/or deform the geometry of the container if the container cannot structurally support the pressure difference between the external ambient pressure and the lower internal pressure of the container. Deformation of the container generally pushes the fluid upwardly and decreases the headspace volume. For example, for a typical 16-ounce container, thermal contraction equates to roughly 3% of the total liquid volume, or 0.9 cubic inches when the stored contents are cooled from about 185° to about 40° F. 
     Current containers are engineered to collapse at specific locations or are reinforced with vacuum panels and/or flexible bases to compensate for the vacuum. Vacuum-reactive mechanisms are very efficient to maintain a balanced pressure and keep the remaining structural geometry of the container from collapsing. Vacuum panels, however, are difficult to mold. Further, labeling of the container is difficult because containers employing raised and/or recessed vacuum panels possess reduced surface area. The reduction of surface area also restricts the ornamental design of the label, restricts the placement of the label, and often leads to unattractive wrinkling of the label. 
     Embodiments of the present invention described herein are directed to an apparatus and method for accommodating the pressure decrease associated with hot filling and subsequently cooling a liquid stored in a plastic container. By addressing the vacuum created within the container, vacuum panels may be eliminated or reduced. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is one aspect of the present invention to provide a method and apparatus for accommodating a pressure change in a plastic bottle that occurs during hot-filling, capping, and subsequently cooling a beverage container. In one embodiment of the present invention a plastic closure cap for containers is provided that define a headspace. When the container and beverage is cooled, the headspace air pressure reduces to a level less than the external pressure felt by the container, i.e., a vacuum is created. A diaphragm is associated with the cap to eliminate or significantly reduce the vacuum in the container. Thus, the container is able to accommodate any pressure differential between the external pressure and the reduced pressure in the container without substantially deforming. 
     It is another aspect of the embodiments of the present invention to provide a closure cap having one or more sealing features associated with the cap. When the cap is positioned on a container neck, the sealing features hermetically seal the cap to the container. As the cap is tightened onto the neck of the container, the sealing mechanism is driven downward and simultaneously compresses the air in the headspace. The increase in pressure is sufficient to compensate the reduction in pressure that occurs when the container is cooled. Distortions generally associated with the pressure decrease are thus avoided. 
     In another aspect of embodiments of the present invention to provide a plastic cap having a “slider ring” is positioned within an annular void within the cap. The slider ring can be a polymeric material having oxygen barrier properties, such as, but not limited to polypropylene, thermoplastic elastomers (TPE), or co-polymers thereof. The slider ring also may include one or more sealing features, such as a cylindrical or semi-cylindrical circumferential features. When the cap is positioned on a container neck, the slider ring hermetically seals the cap to the container, and creates a seal between the cap and the internal surface of the neck of the container. Air within the container is prevented from escaping as the cap is tightened onto the container neck which pressurizes the trapped air in the headspace. The pressure increase is designed to accommodate the pressure decrease experienced during cooling of the stored contents, thus eliminating or significantly reducing any pressure drop or vacuum in the container. 
     It is yet another aspect of embodiments of the present invention is to provide a plastic cap closure having a flexible bellows. The flexible bellows extend within the neck of the container to reduce or eliminate the vacuum. During attachment of the closure to the neck of the container, the bellows is compressed to force air positioned therein into the container which creates a pressure increase within the container. The pressure increase is sufficiently large such that when the container is cooled, a pressure decrease sufficient enough to distort the container will not form. 
     Still yet another aspects of embodiments of the present invention is to provide a closure cap having one or more sealing features within the cap and/or a method of applying the cap to a container which limits the head pressure during the sealing process. More specifically, when sealed under excessive pressure, the container can expand and/or reform. Thus, one embodiment of the present invention reduces the headspace pressure to substantially prevent bursting of the container. An optimal headspace pressure is contemplated that is less than the burst pressure of the container and less than the container distortion pressure. For example, the closure cap may at least partially vent the air entrained in the headspace to maintain the optimal headspace pressure, or can alternatively vent during removal of the cap to allow easier removal of the cap from the container. Alternatively, the capping process can be conducted to achieve the optimal pressure, as for example, by capping at an optimally preferred temperature and/or with an optimally preferred headspace volume. 
     It is yet another aspect of embodiments of the present invention to employ a movable diaphragm that accommodates the pressure decrease. The diaphragm includes a head that transitions from a first position of use, adjacent to an inner surface of the cap, to a second position of use, within the neck of the container, to compensate any pressure decrease or increase. In order to allow for the head of the diaphragm to move downwardly, air is communicated from outside the container into a space between the head of the diaphragm and the inner surface of the cap. The air is prevented from contacting the contents of the container by a non-permeable portion of the diaphragm. When the cap is removed from the container, the head of the diaphragm, preferably, transitions automatically upwardly to engage the inner surface of the cap. 
     It is still yet another aspect of the present invention to provide a container that is easy to label or add indicia thereto. By omitting the need for vacuum panels, embodiments of the present invention provide greater label contact area. The containers, thus, are designed to be more distinctive in shape without requiring about 50% of the visible surface area being dedicated to vacuum panels. Furthermore, containers of the present invention are designed around structural integrity instead of collapse, thus resulting in lighter bottles and material savings. 
     Although these aspects of the invention have been described separately, one of skill in the art will appreciate that some or all variations of the inventions may be combined. Further, the Summary of the Invention is neither intended not should be construed as being representative of the full extent and scope of the present invention. The present invention is set forth in various levels of detail in the Summary of the Invention and as well in the attached drawings and in the detailed description of the invention and not limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the present invention will be come more readily apparent from the Detailed Description, preferably when taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts one embodiment of the present invention that utilizes a sealing slider ring wherein a cap is shown initially engaged on a container neck; 
         FIG. 2  shows the embodiment of  FIG. 1  wherein the cap is shown fully interconnected to the container neck; 
         FIG. 3  is a detailed view of  FIG. 2 ; 
         FIG. 4  depicts another embodiment of the present invention that utilizes a bellows shown initially contacts the container neck; 
         FIG. 5  shows the embodiment of  FIG. 4  wherein the cap is shown fully interconnected to the container neck; 
         FIG. 6  is a partial cross-sectional view of the cap of another embodiment of the present invention shown positioned on a container neck prior to sealing; 
         FIG. 7  is a partial cross-sectional view of the cap shown in  FIG. 6  fully interconnected to a container neck; 
         FIG. 8  is a bottom perspective view of a cap of another embodiment of the present invention that employs a selectively deflectable diaphragm; 
         FIG. 9  is a cross-sectional perspective view of the cap shown in  FIG. 8  wherein the diaphragm has been omitted for clarity; 
         FIG. 10  is a cross-sectional perspective view of the diaphragm shown in  FIG. 8 ; 
         FIG. 11  is a front elevation view of the cap of  FIG. 8  shown initially engaged on a container neck; 
         FIG. 12  is a front cross-section of  FIG. 11 , wherein the diaphragm is shown positioned in a first position of use; 
         FIG. 13  is a perspective view of  FIG. 12 ; 
         FIG. 14  is a front elevation view of the cap of  FIG. 8  shown completely sealed onto a container neck; 
         FIG. 15  is a front cross-section of  FIG. 14 , wherein the diaphragm is shown positioned in a first position of use; 
         FIG. 16  is a perspective view of  FIG. 15 ; 
         FIG. 17  is a front elevation view of the cap of  FIG. 8  shown completely interconnected to the container neck; 
         FIG. 18  is a cross-sectional view of  FIG. 17  wherein the diaphragm is shown in a second position of use, thereby accommodating a pressure decrease in the sealed container; 
         FIG. 19  is a perspective view of  FIG. 18 ; 
         FIG. 20  is a front elevation view of the cap shown in  FIG. 8  shown removed from the container neck; and 
         FIG. 21  is a cross-sectional view of  FIG. 20  wherein the diaphragm has rebounded to its first position of use. 
     
    
    
     To assist in the understanding of the present invention the following list of components and associated numbering found in the drawings is provided herein: 
     
       
         
               
               
             
               
               
             
           
               
                   
               
               
                 # 
                 Component 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 2 
                 Container neck 
               
               
                 6 
                 Cap 
               
               
                 10 
                 Slider ring 
               
               
                 14 
                 Inner surface 
               
               
                 18 
                 Inner surface of the neck 
               
               
                 22 
                 Interior portion 
               
               
                 26 
                 Bellows 
               
               
                 30 
                 Sealing mechanism 
               
               
                 34 
                 Headspace 
               
               
                 38 
                 Container outer surface 
               
               
                 42 
                 Container top surface 
               
               
                 46 
                 Container thread 
               
               
                 100 
                 Closure 
               
               
                 102 
                 Closure Upper End 
               
               
                 104 
                 Skirt Portion of Closure 
               
               
                 110 
                 First seal element 
               
               
                 112 
                 Second seal element 
               
               
                 114 
                 Seal Retention Feature 
               
               
                 116 
                 Seal Retention Leg 
               
               
                 118 
                 Seal Retention Arm 
               
               
                 120 
                 Upper Surface of Seal Retention Arm 
               
               
                 122 
                 Lower Surface of Seal Retention Arm 
               
               
                 124 
                 Retaining Lip 
               
               
                 126 
                 Closure Internal Thread System 
               
               
                 128 
                 Closure Skirt Projection 
               
               
                 130 
                 Inner Top Surface of Closure 
               
               
                 132 
                 Inner Skirt Surface of Closure 
               
               
                 134 
                 Lower End of Seal Retention Leg 
               
               
                 136 
                 First Sealing Groove 
               
               
                 138 
                 Second Sealing Groove 
               
               
                 140 
                 First Seal 
               
               
                 142 
                 Second Seal 
               
               
                 144 
                 Fully Seated Closure Position 
               
               
                 146 
                 First Side of Retention Leg 
               
               
                 148 
                 Second Side of Retention Leg 
               
               
                 300 
                 Cap 
               
               
                 304 
                 Diaphragm 
               
               
                 308 
                 Side wall 
               
               
                 312 
                 Main panel 
               
               
                 316 
                 Inner surface 
               
               
                 320 
                 Fin 
               
               
                 324 
                 Head portion 
               
               
                 328 
                 Threads 
               
               
                 332 
                 Threads 
               
               
                 336 
                 T/E band 
               
               
                 340 
                 Bridge 
               
               
                 344 
                 T/E catch 
               
               
                 348 
                 Grip 
               
               
                 352 
                 Gap 
               
               
                 356 
                 Upper catch 
               
               
                 360 
                 Lower catch 
               
               
                 364 
                 Inner skirt 
               
               
                 368 
                 Outer skirt 
               
               
                 372 
                 Convolution 
               
               
                 376 
                 Seal 
               
               
                 380 
                 Catch ring 
               
               
                 384 
                 Vent 
               
               
                 388 
                 Rebound disk 
               
               
                 392 
                 Neck 
               
               
                 396 
                 Inner portion 
               
               
                 400 
                 Inclined surface 
               
               
                 404 
                 Air 
               
               
                   
               
             
          
         
       
     
     It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein. 
     DETAILED DESCRIPTION 
     Referring now to the drawings,  FIGS. 1-3  depict a closing sequence for one embodiment of the present invention. More specifically, a neck  2  of a plastic bottle is shown with a threaded cap  6  positioned on an uppermost portion. A sealing ring  10  that seals the cap  6  to the neck  2  during the closing sequence is also shown. In operation, the cap  6  is placed on the neck portion  2  of the container after the container is hot-filled with a beverage. A seal is created by the sealing ring  10  to prevent the escape of gas located between the fluid and the inner surface  14  of the threaded cap  6 . As the cap  6  is rotated, the air between the inner surface  14  and the fluid (i.e., headspace) is pressurized. The seal formed between the interior  18  of the neck  2  of the container and the sealing ring  10  positioned on the interior portion  22 , or fin of the cap  6 . As the cap  6  is screwed downward, the seal between the neck  2  and the cap  6  prevents any gas from escaping, and a positive pressure is created within the headspace of the container. 
     Referring now to  FIGS. 4 and 5 , a pressure compensating member in the form of a bellows  26  is shown. More specifically, the neck  2  of a plastic bottle is shown with the threaded cap  6  positioned on an uppermost portion. The cap  6  includes a bellows system  26  with a sealing mechanism  30  at one end thereof. In operation, the cap  6  is placed on the neck portion  2  of the container after the container is hot-filled with a beverage. Upon contact the seal  30  is created that prevents the escape of gas located in the headspace  34 . As the cap  6  is rotated, the bellows  26  is compressed and forces the air therein into the headspace  34 . The seal  30  is formed between the interior of the neck  2  of the container and the bellows  26  positioned on one end of the bellows  26 . As the cap is screwed onto the neck  2 , the seal  30  between the neck  2  and the bellows  26  prevents any gas from escaping, and a positive pressure is created within the headspace  34 . 
     Referring now to  FIGS. 6 and 7 , a threaded cap  100  representing another embodiment of the present invention is shown. More specifically, the cap  100  is comprised of an upper end  102  with a skirt portion  104  extending therefrom, and may include an anti-pilfer band interconnected to the skirt  104  by a score line. The cap  100  is may be comprised of a plastic material, preferably, an injection moldable thermoplastic plastic material having oxygen barrier properties. Alternatively, the cap may be comprised of metallic materials or a combination thereof. 
     A seal retention feature  114  positioned substantially concentrically within the plastic closure cap  100 , and held within the cap  100  by a retaining lip  124  and a closure upper end  102 . In one embodiment, the seal retention feature  114  includes a seal retention arm  118  and a seal retention leg  116 . The seal retention leg  116  has a lower end  134 , a first side  146  and opposing second sides  148 . The seal retention arm  118  has an upper surface  120  and lower surface which generally oppose each other. The seal retention arm  118  and seal retention leg  116  can be separate and distinct elements which are joined together to form the seal retention feature  114 , or the seal retention arm  118  and leg  116  leg can be elements of the seal retention feature  114 . In one embodiment, the cross-section of the retention feature  114  can resemble an inverted letter “L”. The retention feature  114  can be any polymeric material, preferably, a plastic material capable of being injected molded. More preferably, the polymeric material is a thermal plastic having oxygen barrier properties, or a material having thermoplastic properties, that can be injected molded. 
     In a one embodiment, first  110  and second seal elements  112  are operably interconnected to the retention feature  114 . The first seal element  110  is positioned in a first seating groove  136  on the retention leg  116  between an inner skirt surface  132  and the retention leg  116 . Preferably, the first seal element  110  is positioned nearer the lower end  134  of the seal retention leg  134  than the lower surface  122  of seal retention arm  118 . The second seal element  112  is positioned in second seating groove  138  on the retention arm  118  between the inner top surface  130  and the retention arm  118 . Preferably, the second seal element  112  is positioned nearer the retention leg  116  than the inner skirt surface  132 . 
     In a preferred embodiment, the first seal element  110  and second seal element  112  are o-rings or other similar sealing devices well known in the art. More specifically the o-ring described herein is generally an elastomeric seal or gasket loop, with any variety of geometries and cross-sections which are designed to be seated in a groove and compressed between two or more parts to form a seal. The seal is maintained as long as the contact pressure of the o-ring exceeds the pressure being maintained by the o-ring. More specifically, the term “sealing device” generally means any compression fit device, wherein pressure cannot escape between the interior of the container and the cap seal. 
     The first seal element  110  and second seal element  112  are selected based on one or more of: chemical compatibility (with, for example, the plastic hot-fill container, the hot fill product, any lubricants, any adhesives, and any associated gases), temperature (such as, but not limited to, closure manufacturing, hot fill, post-fill, retail, and consumer-use temperatures), sealing pressure (that is, the pressure to form and maintain the seal), lubrication requirements (for the seal to slide along the container), food safety requirements (for example, governmental, agency, trade, and corporate), and cost. 
     The first seal element  110  and second seal element  112  can be any suitable thermoplastic polymer, thermoset rubber, or co-polymer or mixture thereof. Preferred thermoplastic polymers are generally: elastomer (TPE) styrenics; polyolefins (TPO), low density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), ultra low-density polyethylene (ULDPE); polyurethanes (TPU) polyethers and polyesters; etheresterelastomers (TEEEs) copolyesters; polyamides (PEBA); melt processible rubbers (MPR); vulcanizates (TPV); and mixtures and/or co-polymers thereof. Preferred thermoset rubbers are generally: butadiene rubber (BR); butyl rubber (IIR or PIB); chlorosulfonated polyethylene (CSM); epichlorohydrin rubber (ECH or ECO); ethylene propylene diene monomer (EPDM); ethylene propylene rubber (EPR); floroelastomers (FKM); nitrile rubber (NBR); perfluoroelastomer (FFKM); polyacrylate rubber (ASM); polycholorprene (CR); polyisoprene (IR); polysulfide rubber (PSR); silicon rubber (SiR); styrene butadiene rubber (SBR); and mixture and/or co-polymers thereof. 
       FIG. 6  depicts a neck of an associated container  2  which is filled with a hot-filled product wherein the cap  100  is initially positioned on the neck of the container. The neck  2  has opposing inner  18  and outer  38  surfaces, a top surface  42 , and thread system  46 . As shown, the closure cap  100  is positioned on the hot-fill container  2  prior to engagement of the closure cap  100  internal thread  126  and container threads (not shown). Prior to positioning the closure cap  100  on the container  2 , the second sealing feature  112  is not in contact with the inner top surface  130 . 
     After positioning the cap  100  on the neck of the container  2 , a downward pressure is applied to the closure cap  100  to form a first seal  140  between the first seal element  110  and the inner surface  18 . Likewise, the applied pressure forms a second seal  142  between the second seal element  112  and the inner top surface  130 . One or more of the first  140  and second  142  seals creates a first headspace volume and first headspace pressure by hermetically sealing the closure  100  to the container  2 . 
     Following or occurring about simultaneously with the formation of the first  140  and second  142  seals, the internal thread  126  and thread  46  systems are engaged by rotating the cap  100 . As the rotation continues, the inner surface  130  advances towards container top surface  42 , decreasing the headspace volume. Decreasing the headspace volume increases the headspace pressure within container  2  (which can be understood and calculated by one or more of the gas laws of Charles, Boyle and Gay-Lussac). 
     The closure cap  100  is rotated until the closure cap  100  is fully seated on the container  2 , fully sealing the container  2  as depicted in  FIG. 7 . In the fully seated position  144 , the upper surface  120  is adjacent to the inner top surface  130  and the top surface  42  is adjacent to the lower surface  122 . The fully sealed container has a second headspace volume significantly less than the first headspace volume and a second headspace pressure significantly greater than the first headspace pressure. The fully sealed container can experience a variety of temperatures during storage, shipment, retail displace, and consumer-use. Typically, the minimum temperature experienced is about 40 degrees Fahrenheit, when the sealed container is refrigerated. 
     It should be appreciated that any temperature change may affect the headspace pressure and a reduction in temperature will decrease the headspace pressure. When the headspace pressure decreases sufficiently to create a vacuum, the hot-fill plastic container can distort. The distortions can be obviated by having the seating of cap  100  on the container  2  generate a sufficiently large headspace pressure to compensate for the decrease in headspace pressure when the container  2  is refrigerated. Thus, the headspace pressure within container  2  is sufficiently large that any decrease of the headspace pressure during cooling or refrigeration will not distort the structural geometric integrity of the plastic container. Thus, a headspace pressure can be generated which is sufficiently large that the container need not have reinforced panels and/or a flexible base to resist distortion during cooling. It is further appreciated that, the second headspace pressure needed to avoid container distortions can be calculated by the ideal gas law (or gas laws of Charles, Boyle, and/or Gay-Lassac). 
     As appreciated by one skilled in the art, the headspace pressure may be altered by at least one or more of the following: the degree to which the container is filled; the initial headspace temperature; the diameter and height of the cap; the dimensions and shape of the container; the physical properties of the container; the physical properties of the material comprising the container; the dimensions and shape of the container neck; the placement of the sealing features (or slider) within the cap; the lowest temperature the sealed container is exposed to and the composition of the gas and/or liquid in the container or headspace. 
     When the cap  100  is rotated to remove the cap from the container, the retention feature  114  contacts the retention lip  124  separating the second seal element  112  and inner top surface  130 , creating a void volume between element  112  and surface  130 . That is, the second seal element  112  and inner top surface  130  are no longer in contact and the second seal  142  no longer exists. When the seal breaks, the cap can subsequently be removed with a reduction in force. Likewise, in the closure removal process, the first seal element  110  and the inner surface  18  are separated by a void and the first seal  140  no longer exists. 
     Referring now to  FIGS. 8-21 , yet another embodiment of a cap  300  is shown that employs a selectively deformable diaphragm  304 . The cap  300  also includes a sidewall  308  that depends from a main panel  312 . The main panel  312  has an inner surface  316  with a plurality of fins  320  extending therefrom. In one embodiment of the present invention a resiliently deflectable diaphragm  304  is positioned such that in a first position of use a head portion  324  thereof rests against the inner surface  316  of the cap  300 . In a second position of use the head portion  324  is positioned in a lower position in a direction toward the stored fluid. 
     Referring now to  FIG. 9 , a cross-sectional view of the cap  300  is shown that comprises the main panel  312  with sidewall  308  extending therefrom. The sidewall  308  includes internally disposed threads  328  for selective engagement with threads  332  of a container neck (see  FIG. 17 , for example). The sidewall  308  also includes the position for attachment of a tamper evidence (“T/E”) band  336  (e.g., Pilfer Proof) via a bridge  340 . The T/E band  336  is used as a visual indicator that the cap has been loosened from the neck. The T/E band  336  also includes a T/E catch  344  that maintains the T/E band  336  on the container neck after the cap  300  is removed or twisted such that one or more of the bridge members  340  break. In order to facilitate twisting of the cap  300  the sidewall  308  may include a plurality of gripping members  348 . Extending from the inner surface  316  of the cap are the plurality of fins  320  that are spaced such that gaps  352  are provided therebetween. The fins  320  also include, in one embodiment of the present invention, an upper catch  356  and a lower catch  360  that selectively position the diaphragm which will be described in further detail below. 
     Referring now to  FIG. 10 , the diaphragm  304  of one embodiment of the present invention is shown. Preferably, the diaphragm  304  is a shaped piece of resiliently deflectable material such as polyethylene, polypropylene, or other similar plastic materials. One skilled in the art, however, will appreciate that other flexible materials can be used without departing from the scope of the invention. The diaphragm  304  includes an inner skirt  364  positioned inwardly from an outer skirt  368  with a convolution  372  therebetween. The outer skirt  368  includes a flange or sealing surface  376  interconnected thereto. A catch ring  380  is either integrally molded onto the seal  376  and/or outer skirt  368  or interconnected to the seal  376 . The catch ring  380  employs at least one vent  384  to allow air to pass from a location beyond an outer surface of the seal  376  to a position between the inner skirt  364  and the outer skirt  368 . Preferably, the diaphragm  304  has a generally flat head portion  324  that is pulled downwardly when the pressure of the fluids stored within the sealed container decreases. In one embodiment of the present invention a rebound disk  388  (or ring) is generally interconnected to the head portion  324  of the diaphragm  304  that is generally rigid and facilitates movement of the head to its upward position when the sealed container is open. 
     Referring now to  FIGS. 11-13 , the cap  300  of the present invention with a diaphragm  304  is shown interconnected to the neck  392  of a container. As illustrated, the seal  376  is engaged to a top portion of the neck  392 . In  FIG. 11 , the cap  300  is shown prior to tightening onto the neck  392 . Prior to tightening, the seal  376  is placed onto the top portion of the neck  392  wherein the seal  376  is positioned between the catch ring  380  and the neck  392 . The rebound disk  388  of the embodiment shown is positioned against an inner surface  316  of the cap  300 . As the cap  300  is rotated, the threads  328  of the cap will come in contact with the threads  332  of the neck  392  to transition the cap  300  downwardly onto the neck  392 . Rotating the cap will move the fin  320  downwardly to contact the convolution  372  of the diaphragm  304 . Further, as the cap is rotated a “pre-pressure”, or air volume is added to the headspace of the container. Thus, the headspace pressure can be increased during the closure of the container as the cap is screwed to the neck of the container. 
       FIGS. 14-19  illustrate the cap  300  sealingly engaged on the container neck  392  with the heated liquid therein.  FIGS. 14-16  show the cap  300  completely tightened onto the container neck  392  wherein the diaphragm  304  is in a first position of use prior to the cooling of the liquid product.  FIGS. 17-19  shows the affect of content cooling on the diaphragm  304 . To seal the container, the cap  300  is placed on the neck  392  such that the seal  376  rests on the upper end of the container neck  392 . The catch ring  380 , which is integrated or otherwise affixed to the seal  376  is also positioned over the upper surface of the container neck  392 . As the cap  300  is rotated onto the container neck  392 , the fins  320  will transition downwardly to contact the convolution  372  of the diaphragm  304 . As this happens, the upper catch  356  of the fin  320  will deflect an inner portion  396  of the catch ring  380  and transition thereby. More specifically, the upper catch ring  380  includes an inclined surface  400  that facilitates the upper catch ring&#39;s  380  transitions past the inner portion  396  of the catch ring  380 . Thereafter, the catch ring  380  is prevented from moving relative to the main panel  312  of the cap  300 , and is maintained relative thereto. 
     Referring now to  FIGS. 20 and 21 , in operation the diaphragm  304  is designed to transition downwardly when the stored product in the container cools. In order to facilitate this downward motion, air from the external environment travels through the threads of the neck  332 , through the vents  384  in the catch ring  380  and through the gaps  352  of the fins  320 . This air  404  enters a space between the main panel  312  of the cap and the head of the diaphragm  304 , provided by the pressure drop, thereby equalizing the pressure inside and outside the container. As one skilled in the art will appreciate, if the contents of the container should subsequently heat up, the pressure of the stored fluids within the container will increase and force the diaphragm  304  upwardly, thereby transitioning air from between the space through the gaps  352  in the fins, through the catch ring vents  384  and subsequently through the threads. The transfer of air into the container is more commonly seen when the cap  300  is removed from the container. 
     More specifically, the cap  300  is rotated in a direction opposite from tightening. As the cap  300  is rotated, the catch ring  380  and associated seal  376  are pulled away from the upper surface of the neck  392 , which allows any pressure differential or vacuum within the container to be quickly equalized. The pressure equalization removes the force that pulls the diaphragm  304  downwardly as seen in  FIGS. 18 and 19 . The diaphragm  304  is then able to return to its first position of use as shown in  FIG. 12 . In order to facilitate this return, a rebound disk  388  that is interconnected to the head portion  324  of the diaphragm  304  is provided. The rebound disk  388  is made of a stiffened material that is radially loaded by an inner wall of the diaphragm  304  when it is pulled downwardly. The rebound disk  388  also keeps the head of the diaphragm  304  substantially planar to allow for even pressure distribution across the same. When the pressure differential is removed, the potential energy stored within the rebound disk  388  is released to aid the resilient nature of the diaphragm  304  to return it to its first position. Also note that the catch ring  380  and seal  376  after removal of the cap  300  remains adjacent to the inner surface  316  thereof. 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.