Patent Publication Number: US-2020298462-A1

Title: Pressure balancing nozzle for blow-molding container preform

Description:
PRIORITY 
     This application claims the benefit of and priority to U.S. Provisional Application, entitled “Pressure Balancing Nozzle For Blow-Molding Container Preform,” filed on Mar. 18, 2019 and having application Ser. No. 62/820,129, and claims the benefit of and priority to U.S. Provisional Application, entitled “Shrouded Nozzle For Reduced Stress On Container Preform Finish,” filed on Mar. 26, 2019 and having application Ser. No. 62/823,784, and claims the benefit of and priority to U.S. Provisional Application, entitled “Shrouded Nozzle For Reduced Stress On Container Preform Finish,” filed on Jun. 26, 2019 and having application Ser. No. 62/866,714, the entirety of all of said applications being incorporated herein by reference. 
    
    
     FIELD 
     Embodiments of the present disclosure generally relate to the field of plastic bottles and preforms. More specifically, embodiments of the disclosure relate to a nozzle for blow-molding a container preform that includes a stepped interior surface. 
     BACKGROUND 
     Plastic containers have been used as a replacement for glass or metal containers in the packaging of beverages for several decades. The most common plastic used in making beverage containers today is polyethylene terephthalate (PET). Containers made of PET are transparent, thin walled, and have the ability to maintain their shape by withstanding the force exerted on the walls of the container by their contents. PET resins are also reasonably priced and easy to process. PET bottles are generally made by a process that includes the blow-molding of plastic preforms which have been made by injection molding of the PET resin. 
     Advantages of plastic packaging include lighter weight and decreased breakage as compared to glass, and lower costs overall when taking both production and transportation into account. Although plastic packaging is lighter in weight than glass, there is still great interest in creating the lightest possible plastic packaging so as to maximize the cost savings in both transportation and manufacturing by making and using containers that contain less plastic. 
     A plastic container for storing liquid contents typically includes a base that extends up to a grip portion suitable for affixing a label, as well as providing a location for grasping the container. The grip portion generally transitions into a shoulder, which connects to a bell. The bell has a diameter that generally decreases as the bell extends upward from the shoulder to a neck and a finish. The finish is adapted to receive a closure, such as a bottle cap, to seal the contents within the interior of the plastic container. 
     In many instances, the closure includes a tamper evidence band that is disposed around the perimeter of the finish. The tamper evidence band generally remains positioned on the finish when an end-user loosens the closure to access the contents within the container. As such, the tamper evidence band and the finish cooperate to indicate to the end-user whether or not the closure has been previously loosened after being installed by the manufacturer. 
     Advantages of plastic containers include lighter weight and decreased breakage as compared to glass, and lower costs overall when taking both production and transportation into account. As such, there is a continuous interest in creating the lightest possible plastic container so as to maximize cost savings in both transportation and manufacturing by making and using containers that contain less plastic. 
     One difficulty that may be encountered when working with relatively light plastic containers is damaging the preforms during the blow-molding process. In some instances, conventional equipment for blow-molding lightweight preforms into containers can crack, scrape, or otherwise damage the preforms, thereby rendering such preforms useless. A finish portion of the lightweight preforms is particularly susceptible to damage due to stress-failures during the blow-molding process. For example, the relatively thin sidewalls of a lightweight preform are predisposed to bulging, or “barreling,” due to blow-mold pressure applied inside the preform. Further, the sidewalls may fatigue or become cracked when a conventional nozzle for blow-molding the preform is inserted into the finish portion of the preform. In some instances, forcibly engaging the preform during blow-molding also causes a neck portion of the preform to become undesirably compressed. As such, there is a need for equipment suitable for forming the lightest possible plastic containers without damaging the thin-walled prefottns during the blow-molding process. Embodiments disclosed herein provide nozzles that can be engaged with lightweight preforms for forming the preforms into plastic containers without damaging the finish portion or the thin walls of the preforms. 
     SUMMARY 
     A nozzle is provided for engaging with lightweight preforms for blow-molding the preforms into plastic containers without damaging the finish portion of the preforms. The nozzle includes a cylindrical portion coupled with other blow-molding equipment and configured to be advanced longitudinally inside the finish portion of a preform. The cylindrical portion may engage an interior seal with a shelf comprising a stepped interior of the finish portion. The cylindrical portion may include a tapered tip configured to tightly engage with a transition surface comprising the stepped interior of the finish portion. An exterior cylinder comprising the nozzle extends over an exterior of the finish portion and engages an exterior seal with a tamper evidence ledge of the finish portion. The exterior cylinder engages the finish portion to eliminate a pressure differential across a thin-walled region of the finish portion during stretching and/or blow-molding the container preform into a container. In some embodiments, the exterior cylinder comprises a shroud configured to extend over an exterior of the finish portion and counteract outwardly directed forces acting on the finish portion during stretching and/or blow-molding the preform to form the container. The exterior cylinder effectively reduces instances of cracking of the finish portion during forming plastic containers. 
     In an exemplary embodiment, a nozzle for forming a container preform into a plastic container comprises: a cylindrical portion coupled with other blow-molding equipment and configured to be advanced longitudinally inside a finish portion of the container preform; an exterior cylinder configured to extend over an exterior of the finish portion and engage a seal with a tamper evidence ledge of the finish portion; and an opening disposed in the cylindrical portion and configured to enable instruments to be inserted into an interior of the container preform for stretching and/or blow-molding the container preform into a container. 
     In another exemplary embodiment, the seal is disposed around an inner circumference of the exterior cylinder and configured to tightly engage with a rounded upper portion of the tamper evidence ledge. In another exemplary embodiment, the seal comprises an O-ring that is configured to tightly press against the rounded upper portion. In another exemplary embodiment, the seal comprises any of a washer, a band, or an edge portion of the exterior cylinder comprised of a material suitable for tightly sealing with the tamper evidence ledge without damaging the surfaces of the finish portion. In another exemplary embodiment, the material comprises any of rubber, silicone, PET that is softer than the PET comprising the preform, and any combination thereof. 
     In another exemplary embodiment, the cylindrical portion comprises a diameter suitable for extending into the interior of the finish portion while providing an advantageous degree of clearance between the cylindrical portion and the interior of the finish portion. In another exemplary embodiment, the exterior cylinder is configured to engage with an exterior surface of the finish portion without exerting an outwardly directed force on a thin-walled region of the finish portion. In another exemplary embodiment, the exterior cylinder is configured to engage the seal with an exterior surface of the finish portion so as to eliminate a pressure differential across a thin-walled region of the finish portion during forming the container preform into the plastic container. In another exemplary embodiment, the exterior surface comprises a rounded upper portion of the tamper evidence ledge. 
     In another exemplary embodiment, the cylindrical portion is configured to engage a seal with a shelf comprising a stepped interior of the finish portion. In another exemplary embodiment, the cylindrical portion comprises a diameter suitable for pressing the seal against the shelf while maintaining clearance between cylindrical portion and the stepped interior. In another exemplary embodiment, the seal is disposed at a forward-most location of the cylindrical portion and configured to tightly engage with the shelf. In another exemplary embodiment, the seal comprises a washer having a squared periphery that is disposed circumferentially around the seal, such that the seal may be tightly engaged with a right-angled profile shape of the shelf during stretching and/or blow-molding the container preform to form the container. In another exemplary embodiment, the seal is configured to contact the shelf without exerting outwardly directed forces on a thin-walled region of the finish portion. In another exemplary embodiment, the seal is configured to exert a contact force on the shelf along a longitudinal axis of the container preform. 
     In an exemplary embodiment, an assembly for forming a plastic container comprises: a finish portion of a container preform configured to rotatably engage with a closure and to seal contents within an interior of a container formed from the container preform; a shelf comprising a stepped interior of the finish portion; a nozzle including a cylindrical portion and a interior seal configured to engage with the shelf; an opening disposed in the cylindrical portion and configured to enable instruments to be inserted into the container preform for stretching and/or blow-molding the container preform into the plastic container; and an exterior cylinder including a seal configured to engage an exterior surface of the finish portion. 
     In another exemplary embodiment, the exterior cylinder is configured to engage the seal with an exterior surface of the finish portion so as to eliminate a pressure differential across a thin-walled region of the finish portion during forming the container preform into the plastic container. In another exemplary embodiment, the exterior surface comprises a rounded upper portion of a tamper evidence ledge comprising the finish portion. In another exemplary embodiment, the shelf comprises a mirror-polished surface capable of receiving the interior seal. In another exemplary embodiment, the shelf includes a right-angled profile shape that is circumferentially disposed within the interior of the finish portion. In another exemplary embodiment, the interior seal comprises a washer having a squared periphery that is disposed circumferentially around the interior seal, such that the interior seal may be tightly engaged with the right-angled profile shape during stretching and/or blow-molding the container preform to form the container. 
     In an exemplary embodiment, a nozzle for forming a container preform into a plastic container comprises: a cylindrical portion coupled with other blow-molding equipment and configured to be advanced longitudinally inside a finish portion of the container preform; a shroud configured to extend over an exterior of the finish portion and support one or more threads of the finish portion; and an opening disposed in the cylindrical portion and configured to enable instruments to be inserted into an interior of the container preform for stretching and/or blow-molding the container preform into a container. 
     In another exemplary embodiment, the cylindrical portion is configured to engage a seal with a shelf comprising a stepped interior of the finish portion. In another exemplary embodiment, the cylindrical portion comprises a diameter suitable for pressing the seal against the shelf while maintaining clearance between cylindrical portion and the stepped interior. In another exemplary embodiment, the seal is disposed at a forward-most location of the cylindrical portion and configured to tightly engage with the shelf. 
     In another exemplary embodiment, the nozzle further comprises a tapered tip configured to tightly engage with a transition surface comprising a stepped interior of the finish portion. In another exemplary embodiment, the tapered tip extends to a circular edge that is configured to forcibly contact the transition surface. In another exemplary embodiment, the circular edge comprises a rigid material and is configured to dig into material comprising the transition surface so as to establish a tight seal between the nozzle and an interior of the preform. In another exemplary embodiment, the circular edge is configured to be pressed against the transition surface such that the force of contact is directed along a longitudinal axis of the container preform. 
     In another exemplary embodiment, the shroud comprises a cylindrical member having an inner diameter suitable for extending over the one or more threads. In another exemplary embodiment, the shroud is configured to support the finish portion during stretching and/or blow-molding the preform to form the container. In another exemplary embodiment, the shroud is configured to counteract any outwardly directed forces acting on the finish portion during stretching and/or blow-molding the preform to form the container. 
     In another exemplary embodiment, the nozzle further comprises a flat sealing surface surrounding the cylindrical portion and configured to contact a top-most surface of the finish portion. In another exemplary embodiment, the flat sealing surface is configured to be tightly pressed against the top-most surface with a degree of force capable of maintaining a suitable pressure inside the preform for blow-molding without undesirably compressing a neck portion of the preform. 
     In an exemplary embodiment, an assembly for forming a plastic container comprises: a finish portion of a container preform configured to rotatably engage with a closure and to seal contents within an interior of a container formed from the preform; a shelf comprising a stepped interior of the finish portion; a nozzle including a cylindrical portion configured to extend into the stepped interior; an opening disposed in the cylindrical portion and configured to enable instruments to be inserted into the container preform for stretching and/or blow-molding the container preform into the plastic container; and a shroud configured to support an exterior of the finish portion. 
     In another exemplary embodiment, the shroud comprises a cylindrical member having an inner diameter suitable for extending over the finish portion. In another exemplary embodiment, the shroud is configured to support the finish portion during stretching and/or blow-molding the preform to form the container. In another exemplary embodiment, the shroud is configured to counteract any outwardly directed forces acting on the finish portion during stretching and/or blow-molding the preform to form the container. 
     In another exemplary embodiment, the assembly further comprises a seal coupled with the cylindrical portion and configured to engage a shelf disposed in the stepped interior. In another exemplary embodiment, the shelf comprises a mirror-polished surface capable of receiving the seal. In another exemplary embodiment, the shelf includes a right-angled profile shape that is circumferentially disposed within the stepped interior. In another exemplary embodiment, the seal comprises a washer having a squared periphery that is disposed circumferentially around the cylindrical portion, such that the seal tightly engages the right-angled profile shape during stretching and/or blow-molding the container preform to form the container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings refer to embodiments of the present disclosure in which: 
         FIG. 1  illustrates a side view of an exemplary container suitable for storing pressurized contents; 
         FIG. 2  a side plan view of an exemplary embodiment of a preform suitable for being blow-molded to form a container in accordance with the present disclosure; 
         FIG. 3  illustrates a close-up cross-sectional view of a sidewall portion of a finish comprising the preform illustrated in  FIG. 2 , according to the present disclosure; 
         FIG. 4  illustrates a cross-sectional view of a container preform including a stepped interior surface that is engaged with an exemplary embodiment of a nozzle for forming lightweight containers according to the present disclosure; 
         FIG. 5  illustrates a close-up cross-sectional view of a sidewall portion of the preform of  FIG. 4  that is engaged with an exemplary embodiment of a nozzle for forming lightweight containers, in accordance with the present disclosure; 
         FIG. 6  illustrates a cross-sectional view of a container preform including a stepped interior surface that is engaged with an exemplary embodiment of a nozzle for forming lightweight containers according to the present disclosure; 
         FIG. 7  illustrates a close-up cross-sectional view of a sidewall portion of the preform of  FIG. 6  that is engaged with an exemplary embodiment of a nozzle for forming lightweight containers, in accordance with the present disclosure; 
         FIG. 8  illustrates a cross-sectional view of a container preform including a stepped interior surface that is engaged with an exemplary embodiment of a shrouded nozzle for forming lightweight containers according to the present disclosure; 
         FIG. 9  illustrates a close-up cross-sectional view of a sidewall portion of the preform of  FIG. 8  that is engaged with an exemplary embodiment of a shrouded nozzle for forming lightweight containers, in accordance with the present disclosure; 
         FIG. 10  illustrates a cross-sectional view of a container preform including a stepped interior surface that is engaged with an exemplary embodiment of a shrouded nozzle for forming lightweight containers according to the present disclosure; 
         FIG. 11  illustrates a close-up cross-sectional view of a sidewall portion of the preform of  FIG. 10  that is engaged with an exemplary embodiment of a shrouded nozzle for forming lightweight containers, in accordance with the present disclosure; 
         FIG. 12  illustrates a cross-sectional view of a container preform including a stepped interior surface that is engaged with an exemplary embodiment of a shrouded nozzle for forming lightweight containers according to the present disclosure; and 
         FIG. 13  illustrates a close-up cross-sectional view of a sidewall portion of the preform of  FIG. 12  that is engaged with an exemplary embodiment of a shrouded nozzle for forming lightweight containers, in accordance with the present disclosure. 
     
    
    
     While the present disclosure is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The invention should be understood to not be limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure. 
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one of ordinary skill in the art that the invention disclosed herein may be practiced without these specific details. In other instances, specific numeric references such as “first bottle,” may be made. However, the specific numeric reference should not be interpreted as a literal sequential order but rather interpreted that the “first bottle” is different than a “second bottle.” Thus, the specific details set forth are merely exemplary. The specific details may be varied from and still be contemplated to be within the spirit and scope of the present disclosure. The term “coupled” is defined as meaning connected either directly to the component or indirectly to the component through another component. Further, as used herein, the terms “about,” “approximately,” or “substantially” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. 
     In general, there is a continuous interest in creating the lightest possible plastic container so as to maximize cost savings in both transportation and manufacturing by making and using containers that contain less plastic. One difficulty often encountered when working with lightweight plastic containers is damaging the preforms during the blow-molding process. For example, the relatively thin sidewalls of a lightweight preform may become bulged due to blow-mold pressure applied inside the preform. In some instances, the sidewalls may fatigue or become cracked when a conventional nozzle for blow-molding the preform is inserted into the finish portion of the preform. Further, in some instances, forcibly engaging the preform during blow-molding undesirably compresses a neck portion of the preform. Embodiments disclosed herein provide nozzles that can be engaged with lightweight preforms for stretching and/or blow-molding the preforms into plastic containers without damaging the finish portion of the preforms. 
       FIG. 1  illustrates a side view of an exemplary container  100  typically used for storing liquid contents, such as water, juice, and particularly carbonated contents. The container  100  comprises a base  104  that extends up to a grip portion  108 . In some embodiments, the base  104  may be of the petaloid variety, although other configurations of the base may be incorporated into the container  100 , without limitation. The grip portion  108  comprises a plurality of grip portion ribs  112  (i.e., sidewall ribs). As illustrated in  FIG. 1 , the plurality of grip portion ribs  112  generally vary in depth, and swirl or angulate around the grip portion  108 . A label portion  116  is connected to the grip portion  108  and comprises one or more label panel ribs (not shown). The label panel portion  116  transitions into a shoulder  124 , which connects to a bell  128 . 
     In the embodiment illustrated in  FIG. 1 , the bell  128  comprises a plurality of design features  132 . In other embodiments, however, the bell  128  may include various other design features, or may be smooth and generally unornamented. The bell  128  connects to a neck  136 , which connects to a finish  140 . As shown in  FIG. 1 , the bell  128  comprises a diameter that generally decreases as the bell  128  extends upward from the shoulder  124  to the neck  136  and the finish  140 . The finish  140  is adapted to receive a closure, such as by way of non-limiting example, a container cap or closure  144 , so as to seal contents within the container  100 . The finish  140  generally defines an opening that leads to an interior of the container  100  for containing a beverage, or other contents, such as any of a variety of carbonated soft drinks. The finish  140  may be of the Carbonated Soft Drink (CSD) variety or may be configured to receive closures suitable for sealing noncarbonated contents within the interior of the container  100 . 
     As shown in  FIG. 1 , a tamper evidence closure  144  may be threadably engaged with the finish  140  of  FIG. 3 . The closure  144  generally includes interior threads that are configured to engage with threads disposed on the finish  140 , as described herein. During tightening of the closure  144  onto the finish  140 , a plug seal of the closure  144  extends into the opening of the container  100  and enters into a pressed relationship with the finish  140  whereby contents may be sealed in the interior of the container  100 . 
     As further shown in  FIG. 1 , the closure  144  includes a tamper evidence band  148  to provide an indication of whether or not the closure  144  has been loosened after being installed by a manufacturer. In some embodiments, the tamper evidence band  148  may be attached to the closure  144  by a multiplicity of thin connections. The tamper evidence band  148  may include a cam that is configured to fixedly engage with a tamper evidence ledge disposed on the finished  140  during loosening of the closure  144 . Once the closure  144  is installed onto the finish  140  by a manufacturer and later an end-user loosens the closure  144 , the cam engages the tamper evidence ledge, breaking the thin connections between tamper evidence band  148  and the closure  144 . The tamper evidence band  148  remains positioned on the tamper evidence ledge after the closure  144  is removed from the container  100 . As such, the tamper evidence band  148  cooperates with the tamper evidence ledge to indicate to the end-user whether or not the closure  144  has been previously loosened after being installed by the manufacturer. 
       FIG. 2  illustrates an exemplary embodiment of a preform  160  suitable for being blow-molded to form a plastic bottle, such as the container  100 , according to the present disclosure. The preform  160  preferably is made of material approved for contact with food and beverages such as virgin PET or recycled PET and can be of any of a wide variety of shapes and sizes. The preform  160  shown in  FIG. 2  is of the type which will form a 12-16 oz. beverage bottle, but as will be understood by those skilled in the art, other preform configurations may be used depending upon the desired configuration, characteristics and use of the final article. The preform  160  may be made by injection molding methods, without limitation. 
     The preform  160  includes a finish portion  164  and a body portion  168 , formed monolithically (i.e., as a single, or unitary, structure). Advantageously, the monolithic arrangement of the preform  160 , when blow-molded into a bottle, provides greater dimensional stability and improved physical properties in comparison to a preform constructed of separate neck and body portions that are bonded together. 
     The finish portion  164  begins at an opening  172  to an interior of the preform  160  and extends to and includes a tamper evidence ledge  176 . The finish portion  164  is further characterized by the presence of one or more threads  180  configured to provide a means to fasten a closure, such as a cap, to the bottle produced from the preform  160 . As such, the threads  180  are configured to rotatably engage with similar threads disposed within the cap to provide a way to seal contents within the bottle. In the embodiment illustrated in  FIG. 2 , each of the threads  180  generally extends along a section of the circumference of the finish portion  164  and approaches the tamper evidence ledge  176 . Thus, when the threads of a cap are engaged with the threads  180 , and the cap is rotated in a clockwise direction, the cap advances toward the tamper evidence ledge  176 . 
     With continuing reference to  FIG. 2 , each of the one or more threads  180  begins at a thread start  184  and extends along an angular section of the finish portion  164 . The thread start  184  is configured to guide the thread  180  into a space, or valley, between adjacent threads of the cap so as to threadably engage the cap with the finish portion  164 . Further, the threads  180  generally are disposed adjacently to one another, separated by a valley  188 , and are spaced uniformly around the circumference of the finish portion  164 . In some embodiments, wherein three threads  180  are disposed around the finish portion  164 , the thread starts  184  of adjacent threads  180  are spaced at substantially 120-degree intervals around the perimeter of the finish portion  164 . As will be appreciated, however, more or less than three threads  180  may be incorporated into the finish portion  164  without deviating beyond the scope of the present disclosure. 
     In some embodiments, a plurality of gaps may be disposed in the threads  180  and positioned uniformly around the perimeter of the finish portion  164 . Preferably, the gaps of adjacent threads  180  are vertically aligned so as to form channels extending longitudinally along the finish portion  164 . The channels advantageously operate to relieve pressure within the container  100  when the container  144  is loosened. As will be appreciated, the channels may provide a direct route for gases escaping the interior of the container  100 , rather than the gases being forced to travel around the finish portion  164  between adjacent threads  180 . 
     The body portion  168  includes a neck portion  192  that extends to a tapered portion  196  of the body portion  168 . The tapered portion  196  comprises a smooth transition from a diameter of the neck portion  192  to a relatively smaller diameter of a cylindrical portion  200  of the preform  160 . The cylindrical portion  200  is a generally elongate member that culminates in an end cap  204 . In some embodiments the body portion  168  may be generally cylindrical, and the end cap  204  may be conical or frustoconical and may also be hemispherical, and the very terminus of the end cap  204  may be flattened or rounded. 
     In some embodiments, a wall thickness of the cylindrical portion  200  may be substantially uniform throughout the cylindrical portion  200  and the end cap  204 . A wall thickness of the tapered portion  196 , however, generally decreases from the wall thickness of the cylindrical portion  200  to a relatively thinner wall thickness of the neck portion  192 . As will be appreciated, the wall thickness of the cylindrical portion  200  is relatively greater than the wall thickness of the neck portion  192  so as to provide a wall thickness at the desired dimensions of a finished product after the preform  160  is blow-molded into the shape and size of a bottle. As such, the wall thickness throughout most of the body portion  168  will depend upon the overall size of the preform  160  and the wall thickness and overall size of the resulting container. 
       FIG. 3  illustrates a close-up cross-sectional view of a sidewall of the finish portion  164  illustrated in  FIG. 2 . As will be appreciated, the finish  164  comprises a cylindrical body that begins at the opening  172  to the interior of the container  100  and extends to and includes the tamper evidence ledge  176 . The finish portion  164  includes a bevel  208  disposed at the beginning of the opening  172 . The bevel  208  is configured to enter into sliding contact with a plug seal of the closure  144  so as to prevent contents from leaking out of the container  100  formed from the preform  160 . In some embodiments, the bevel  208  operates to guide the plug seal onto a sealing surface  212  disposed on an interior of the finish portion  164 . In general, the bevel  208  and the sealing surface  212  comprise portions of the interior of the finish portion  164  that extend circumferentially around the opening  172 . 
     As will be appreciated, the sealing surface  212  must comprise a sufficiently smooth surface capable of cooperating with the plug seal to retain contents under pressure, such as carbonated contents, within the container  100 . To this end, it is contemplated that the sealing surface  212  may be highly polished so as to be substantially free of surface defects and thus conditioned to form a tight seal with the plug seal of the closure  144 . Preferably, the sealing surface  212  is to be polished to a degree of smoothness that is commonly associated with a mirror finish. As such, it is contemplated that the sealing surface  212  comprises a mirror polished region along the interior of the finish portion  164 . Further, in some embodiments, the bevel  208  may also be conditioned to comprise a mirror polished region at the beginning of the opening  172 . Any of various techniques may be used to mirror polish either or both of the sealing surface  212  and the bevel  208 , without limitation. 
     As shown in  FIG. 3 , the sealing surface  212  extends away from the bevel  208 , deeper into the opening  172  to a transition surface  216 . The transition surface  216  comprises a region within the interior of the finish portion  164  wherein the interior diameter of the opening  172  generally narrows from the diameter of the sealing surface  212  to a smaller diameter of a handing surface  220 . In the embodiment illustrated in  FIG. 3 , the transition surface  216  comprises a reverse curve surface that includes a concave portion  224  that extends from the sealing surface  212  and joins with a convex portion  228  that extends to the handing surface  220 . As will be recognized, the handling surface  220  includes a diameter of the opening  172  that is configured to receive various forms of equipment used to configure the preform  160  into the container  100 . 
     It is contemplated that the transition surface  216  is to be capable of cooperating with the plug seal of the closure  144  to form a tight seal between the closure  144  and the container  100 . In some embodiments, the concave portion  224  may be configured to forcibly receive an end of the plug seal so as to form a tight seal therebetween. Further, in some embodiments, the convex portion  228  may be configured to forcibly receive the end of the plug seal. As such, the transition surface  216  may include a smooth surface that is polished similarly to the sealing surface  212 . It is envisioned that the transition surface  216  may be mirror polished, as described hereinabove with respect to the sealing surface  212 . 
     Moreover, in some embodiments, the plug seal of the closure  144  may be configured to extend into the opening such that the plug seal cooperates with the handling surface  220  to seal the container  100 . In such embodiments, the plug seal may include a sidewall shape that mates with the concave and convex portions  224 ,  228 . As will be appreciated, therefore, the handling surface  220  may be mirror polished similarly to the sealing surface  212  and the transition surface  216 . It is contemplated that mirror polished surface may be achieved by way of any of various suitable polishing techniques, such as mechanical machining and buffing, chemical treatments, plasma treatments, and the like, without limitation. 
     In some embodiments, such as the illustrated embodiment of  FIG. 3 , a secondary transition surface  244  may be disposed between the handling surface  220  and an interior surface  248  of the body portion  168 . In general, the secondary transition surface  244  comprises a region within the interior of the finish portion  164  wherein the interior diameter of the opening  172  narrows from the diameter of the handling surface  220  to a smaller diameter of the interior surface  248 . In the embodiment illustrated in  FIG. 3 , the secondary transition surface  244  comprises a reverse curve surface that includes a concave portion  252  that extends from the handling surface  220  to a convex portion  256  that extends to the interior surface  248 . 
     In some embodiments, the secondary transition surface  244  may be configured to cooperate with the plug seal of the closure  144  to form a tight seal between the closure  144  and the container  100  suitable for storing pressurized contents, such as carbonated beverages, within the container  100 . As such, the concave portion  252  may be configured to tightly receive an end of the plug seal to form a tight seal therebetween. In some embodiments, the convex portion  256  may be configured to forcibly receive and compress the end of the plug seal. To this end, the secondary transition surface  244  preferably includes a smooth surface that is polished similarly to the sealing surface  212 . It is envisioned that the secondary transition surface  244  may be mirror polished, as described hereinabove with respect to the sealing surface  212 . 
     In some embodiments, the plug seal of the closure  144  may be configured to extend into the opening  172  such that the plug seal extends beyond the secondary transition surface  244  and thus cooperates with the portion of the interior surface  248  near the convex portion  256 . In some embodiments, the interior surface  248  may have a diameter that tightly compresses the end of the plug seal to seal the pressurized contents within the container  100 . It is contemplated that, in some embodiments, the plug seal may include a sidewall profile that mates with the concave and convex portions  252 ,  256 . As such, the interior surface  248  preferably is mirror polished similarly to the mirror polish of the sealing surface  212 . As disclosed hereinabove, the mirror polished surface may be achieved by way of any of various suitable polishing techniques, such as mechanical machining and buffing, chemical treatments, plasma treatments, and the like, without limitation. 
     In the embodiment illustrated in  FIG. 3 , the surfaces  212 ,  220 ,  248  generally comprise a stepped interior of the finish portion  164 . As such, the stepped interior comprises a graduated narrowing of the opening  172  that extends from the bevel  208 , through the finish portion  164 , to the tamper evidence ledge  176 . It is contemplated that the stepped interior comprises multiple sidewall portions of the finish  164  that may be configured to advantageously minimize the quantity of resin comprising the finish portion  164 , as compared to finish portions comprising a substantially uniform diameter. 
     In some embodiments, the stepped interior may be configured to compressibly receive a plug seal of the closure  144  that comprises graduated seals configured to tightly engage with the graduated narrowing of the opening  172 . For example, the stepped interior can include one or more sealing surfaces that are each configured to tightly engage with one of the graduated seals of the plug seal to contribute to forming a tight seal between the closure  144  and the container  100 . As will be appreciated, therefore, the graduated seals of the plug seal generally include diameters that are suitable for engaging with the graduated narrowing of the opening  172  so as to seal pressurized contents, such as carbonated beverages, within the container  100 . It is contemplated that the one or more sealing surfaces comprise mirror-polished surfaces that are joined together by transition surfaces. Further, the transition surfaces are contemplated to comprise mirror-polished surfaces that cooperate with the one or more seals of the plug seal so as to contribute to forming the tight seal between the closure  144  and the container  100 . 
     In the exemplary embodiment shown in  FIG. 3 , the sealing surface  212  is configured to compressibly receive a first seal comprising the plug seal, and the handing surface  220  is configured to compressibly receive a second seal of the plug seal. Further, the interior surface  248  may be configured to compressibly receive a third seal comprising the plug seal. According, the sealing surface  212  includes a first diameter configured to tightly compress the first seal of the plug seal, and the handling surface  220  includes a second diameter configured to tightly compress the second seal. The interior surface  248  includes a third diameter configured to tightly compress the third seal of the plug seal. As will be appreciated, the third diameter is equal to or less than the second diameter, and the second diameter is equal to or less than the first diameter. Further, the transition surface  216  comprises a change in diameter of the opening  172  that transitions from the first diameter of the sealing surface  212  to the second diameter of the handling surface  220 . The secondary transition surface  244  comprises a change in diameter of the opening  172  that transitions from second diameter of the handling surface  220  to the third diameter of the interior surface  248 . As disclosed hereinabove, the transition surfaces  216 ,  244  comprise mirror-polished surfaces that may be formed by way of any of various suitable polishing techniques. 
     With continuing reference to  FIG. 3 , the tamper evidence ledge  176  comprises a rounded upper portion  232  and a substantially flat lower portion  236 . The rounded upper portion  232  facilitates passing the tamper evidence band  148  of the closure  144  over the tamper evidence ledge  176  during assembly of the closure  144  onto the container  100 . The flat lower portion  236  is configured to retain the tamper evidence band  148  positioned below the tamper evidence ledge  176  during loosening of the closure  144 . For example, when the closure  144  is initially installed onto the container  100  by a manufacturer, the tamper evidence band  148  easily passes over the tamper evidence ledge  176  due to the rounded upper portion  232 . When an end-user later loosens the closure  144 , the flat lower portion  236  retains the tamper evidence band  148  below the tamper evidence ledge  176 , causing the tamper evidence band  148  to break loose from the closure  144 . Thus, the flat lower portion  236  of the tamper evidence ledge  176  and the tamper evidence band  148  of the closure  144  cooperate to indicate to the end-user that the closure  144  has not been previously loosened after being installed by the manufacturer. It should be understood, however, that the tamper evidence ledge  176  is not limited to being coupled with tamper evidence bands, as described above, but rather the tamper evidence ledge  176  may be configured to operate with any of various devices for indicating whether or not the container has been previously opened. 
     Disposed between the tamper evidence ledge  176  and the threads  180  is a handling valley  240  that extends circumferentially around the finish portion  164 . The handling valley  240  comprises a portion of the finish portion  164  that has a wall thickness and a diameter that are substantially similar to the wall thickness and diameter of the neck portion  192 , below the tamper evidence ledge  176 . As such, the handling valley  240  and the neck portion  192  advantageously enable gripping fingers to engage with and support the container  100  during air-conveying the container  100  along a manufacturing assembly. For example, a first pair of gripping fingers can extend into the handling valley  240  to support the container  100  at a first station of a manufacturing line. Then, upon being conveyed to a second station, a second pair of gripping fingers can extend around the neck portion  192 , below the tamper evidence ledge  176 , while the first pair of gripping fingers are removed from the handling valley  240 . Similarly, upon arriving at a third station, a third pair of gripping fingers can engage with the handling valley  240  while the second pair of gripping fingers are removed from the neck portion  192 . Thus, the container  100  can be transported along the manufacturing line by alternatingly engaging gripping fingers with the handling valley  240  and the neck portion  192 . 
     As will be appreciated, the handling valley  240  provides a separation between the tamper evidence ledge  176  and the threads  180  suitable for receiving the pair of gripping fingers, as described above. In general, the separation must be large enough to allow the gripping fingers to easily pass between the tamper evidence ledge  176  and the threads  180 . As such, any of various separations, greater than the width of the gripping fingers, may be disposed between the tamper evidence ledge  176  and the threads  180 , without limitation and without deviating beyond the scope of the present disclosure. 
     Turning now to  FIG. 4 , a nozzle  260  for blow-molding the preform  160  into a container, such as the container  100 , is shown inserted into the finish portion  164  and engaged with the stepped interior. The nozzle  260  generally comprises a cylindrical portion  264  that may be coupled with other blow-molding equipment  262  and is configured to be advanced along a longitudinal axis  266  of the preform  160  so as to tightly engage with the finish portion  164 . The nozzle  260  includes an opening  268  whereby instruments may be inserted into the preform  160  for stretching and/or blow-molding the preform  160  into the container  100 . In the illustrated embodiment of  FIGS. 4-5 , the cylindrical portion  264  comprises a diameter suitable for extending into interior of the finish portion  164  while maintaining an advantageous degree of clearance between the mirror-polished surfaces  212 ,  220 ,  248  and the cylindrical portion  264 . As will be appreciated, preventing contact between the cylindrical portion  264  and the surfaces  212 ,  220 ,  248  substantially eliminates potential damage occurring to the mirror-polished surfaces within the finish portion  164 . 
     As shown in  FIGS. 4-5 , the nozzle  260  further includes an exterior cylinder  270  that is configured to extend over the threads  180  of the finish surface  164  and engage with the tamper evidence ledge  176 . A seal  272  is disposed around an inner circumference of the exterior cylinder  270  and configured to tightly engage with the rounded upper portion  232  of the tamper evidence ledge  176 . In some embodiments, the seal  272  comprises an O-ring that is configured to tightly press against the rounded upper portion  232  without damaging the surface or the threads  180  of the finish portion  164 . It is contemplated, however, that the seal  272  is not to be limited to O-rings, but rather the seal  272  may comprise any device capable of sealing the nozzle  260  to the tamper evidence ledge  176  for the purpose of stretching and/or blow-molding the preform  160  into the container  100 . In some embodiments, for example, the seal  272  may include a washer, a band, or an edge portion of the exterior cylinder  270  comprised of a material suitable for tightly sealing with the tamper evidence ledge  176  without damaging the surfaces of the finish portion  164 . The material comprising the seal  272  may be any material that is generally suitable for sealing with the PET comprising the preform  160 , such as, by way of non-limiting example, rubber, silicone, relatively softer PET that the PET comprising the preform  160 , any combination thereof, and the like. 
     As best shown in  FIG. 5 , the sealing surface  212  of the finish portion  164  is surrounded by a thin-walled region  276 . In the case of lightweight preforms, such as the preform  160 , the thin-walled region  276  is susceptible to being damaged by contact with conventional blow-molding nozzles. In particular, outwardly-directed forces on the thin-walled region  276 , such as due to forcible contact between the surface  212  and a conventional nozzle or internal pressure during blow-molding the preform  160 , tends to damage the sealing surface  212  and/or crack the thin-walled region  276 . Such outwardly directed forces may be eliminated, however, by engaging the seal  272  with an exterior surface of the finish portion  164 , such as the rounded upper portion  232  of the tamper evidence ledge  176 , as described herein. As will be appreciated, engaging the seal  272  with the tamper evidence ledge  176  during stretching and/or blow-molding the preform  160  allows the pressure outside the finish portion  164  to equalize with the internal pressure applied to blow the preform  160  into the container  100 . In absence of a pressure differential across the thin-walled region  276  of the finish portion  164 , outward forces on the finish portion  164  are eliminated. As such, engaging the seal  272  with the tamper evidence ledge  176  allows for tighter sealing between the preform  160  and the nozzle  260  as well as facilitating greater internal pressure within the preform  160  without cracking the thin-walled region  276  of the finish portion  164 . 
     In the embodiment of the nozzle  260  illustrated in  FIGS. 4-5 , a tapered tip  280  is disposed forward of the cylindrical portion  264 . The tapered tip  280  comprises a decrease in the diameter of the cylindrical portion  264  that is configured to accommodate the stepped interior of the preform  160 . As shown in  FIG. 5 , the tapered tip  280  generally provides clearance between the cylindrical portion  264  and the narrowing interior diameter of the surfaces  212 ,  220 ,  248  within the finish portion  164 . The tapered tip  280  is not limited to comprising a linearly tapering diameter of the cylindrical portion  264 , as shown in  FIG. 5 , but rather other shapes are contemplated. For example, in one embodiment, the tapered tip  280  comprises an inwardly rounded portion of the cylindrical portion  264  that is configured to prevent damage to the mirror-polished surfaces inside the finish portion  164  during insertion of the nozzle  260  into the preform  160 . In some embodiments, however, the tapered tip  280  may be omitted from the nozzle  260 , without limitation. 
       FIGS. 6-7  illustrate an exemplary embodiment of a nozzle  300  for blow-molding the preform  160  into a container, such as the abovementioned container  100 . The nozzle  300  is shown inserted into the finish portion  164 , parallel to the longitudinal axis  266 , and engaged with the stepped interior of the preform  160 . The nozzle  300  comprises a cylindrical portion  304  that may be coupled with other blow-molding equipment  262 . The cylindrical portion  304  includes a seal  308  that is configured to tightly engage with a shelf  302  disposed in the interior surface of the finish portion  164  of the preform  160 . The nozzle  300  includes an opening  312  whereby instruments may be inserted into the preform  160  for stretching and/or blow-molding the preform  160  into the container  100 . The seal  308  is disposed around the circumference of the cylindrical portion  304  and configured to tightly press against the shelf  302  without damaging the surfaces  212 ,  220  or the sidewall of the finish portion  164 . As such, it is contemplated that the preform  160  may be pressed onto the nozzle  300  during stretching and/or blow-molding the preform  160  to form the container  100 . 
     As best shown in  FIG. 5 , the shelf  302  includes profile shape  306  that is generally squared, or right-angled. Accordingly, the seal  308  includes a squared periphery  310  that is disposed circumferentially around the seal  308 , such that the seal  308  may be tightly engaged with the profile shape  306  of the shelf  302  during stretching and/or blow-molding the preform  160  to form the container  100 . It is contemplated, however, that the seal  308  is not to be limited to the configuration shown in  FIG. 5 , but rather the seal  308  may comprise any of various configurations capable of engaging with various configurations of the shelf  302 . For example, in some embodiments, the seal  308  may be an O-ring configured to be received by a concaved profile shape of the shelf  302 . As such, the seal  308  may include a washer, a band, or an edge portion of the cylindrical portion  304  comprised of a material suitable for tightly sealing with the shelf  302  without damaging the interior surfaces of the finish portion  164 . The material comprising the seal  308  may be any material that is generally suitable for sealing with the PET comprising the preform  160 , such as, by way of non-limiting example, rubber, silicone, relatively softer PET that the PET comprising the preform  160 , any combination thereof, and the like. 
     With continuing reference to  FIG. 7 , the seal  308  is configured to be pressed against the shelf  302  such that the force of contact is directed parallel to the longitudinal axis  266  and along the sidewall of the finish portion  164 . As will be appreciated, orienting the contact force parallel to the sidewall of the finish portion  164  allows for tighter sealing between the nozzle  300  and the preform  160 . Further, the force is distributed throughout an area of contact between the seal  308  and the shelf  302 . As such, the total pressure exerted on the finish portion  164  by the nozzle  300  is lower than the total pressure exerted by conventional nozzles that include O-rings. Those skilled in the art will appreciate that reducing the total pressure exerted on the finish portion  164  facilitates utilizing greater internal pressures within the preform  160  without cracking the thin-walled region  276  of the finish portion  164  during stretching and/or blow-molding the preform  160  to form the container  100 . 
     Similar to the nozzle  260  of  FIGS. 4-5 , the nozzle  300  includes an exterior cylinder  320  that is configured to extend over the threads  180  of the finish surface  164  and engage with the tamper evidence ledge  176 . A seal  324  is disposed around an inner circumference of the exterior cylinder  320  and configured to tightly engage with the rounded upper portion  232  of the tamper evidence ledge  176 . In some embodiments, the seal  324  comprises an O-ring configured to tightly press against the rounded upper portion  232  without damaging the surface or the threads  180  of the finish portion  164 . The seal  324  is not to be limited to O-rings, however, but rather the seal  324  may comprise any device capable of sealing the nozzle  300  to the tamper evidence ledge  176  for the purpose of stretching and/or blow-molding the preform  160  into the container  100 . For example, the seal  324  may comprise any of a washer, a band, or an edge portion of the exterior cylinder  320  comprised of a material suitable for tightly sealing with the tamper evidence ledge  176  without damaging the surfaces of the finish portion  164 . The material comprising the seal  324  may be any material that is generally suitable for sealing with the PET comprising the preform  160 , such as, by way of non-limiting example, rubber, silicone, relatively softer PET that the PET comprising the preform  160 , any combination thereof, and the like. 
     As described hereinabove, in the case of lightweight preforms, such as the preform  160 , the thin-walled region  276  surrounding the sealing surface  212  is susceptible to being damaged by contact with conventional blow-molding nozzles. Outward forces on the thin-walled region  276 , due to forcible contact between the surface  212  and a conventional nozzle or internal pressure during blow-molding the preform  160 , tends to damage the sealing surface  212  and/or crack the thin-walled region  276 . The nozzle  300  eliminates such outwardly directed forces, however, by engaging the seal  324  with the rounded upper portion  232  of the tamper evidence ledge  176 , in addition to engaging the shelf  302  inside the finish portion  164 . As will be appreciated, sealing the tamper evidence ledge  176  and the shelf  302  allows pressure to remain equalized across the thin-walled region  276  during stretching and/or blow-molding the preform  160  to form the container  100 . In absence of a pressure differential across the thin-walled region  276  of the finish portion  164 , outward forces on the finish portion  164  are eliminated. As such, engaging the seal  272  with the tamper evidence ledge  176  allows for tighter sealing between the preform  160  and the nozzle  300  as well as facilitating greater internal pressure within the preform  160  without cracking the thin-walled region  276  of the finish portion  164 . 
     Turning now to  FIG. 8 , a nozzle  360  for blow-molding the preform  160  into a container, such as the container  100 , is shown inserted into the finish portion  164 . The nozzle  360  generally comprises a cylindrical portion  364  that is coupled with other blow-molding equipment  262  and is configured to be advanced along the longitudinal axis  266  of the preform  160  so as to tightly engage a top-most surface  242  of the finish portion  164  with a sealing surface  246  surrounding the nozzle  360 . The cylindrical portion  364  includes an opening  368  whereby instruments may be inserted into the preform  160  for stretching and/or blow-molding the preform  160  into the container  100 . The sealing surface  246  comprising the blow-molding equipment  262  is configured to be tightly pressed against the top-most surface  242  with a degree of force capable of maintaining a suitable pressure inside the preform for blow-molding without undesirably compressing the neck portion  192 . As best shown in  FIG. 9 , the sealing surface  246  may comprise a ring-shaped protrusion having a circumference suitable for contacting the entire circumference of the top-most surface  242  of the finish portion  164 . 
     In the illustrated embodiment of  FIGS. 8-9 , the cylindrical portion  364  comprises a diameter suitable for extending into interior of the finish portion  164  while maintaining an advantageous degree of clearance between the mirror-polished surfaces  212 ,  220 ,  248  and the cylindrical portion  364 . Experimental observation has demonstrated that preventing contact between the cylindrical portion  364  and the surfaces  212 ,  220 ,  248  substantially eliminates potential damage occurring to the mirror-polished surfaces within the finish portion  164 . 
     As shown in  FIG. 8 , the nozzle  360  further includes an exterior shroud  372  that is configured to extend over the threads  180  of the finish surface  164 . The shroud  372  generally is a cylindrical member having an inner diameter suitable for being extended over the exterior of the finish portion  164  without damaging the threads  180 . The shroud  372  is configured to provided support to the finish portion  164  during stretching and/or blow-molding the preform  160  into the container  100 , as described herein. 
     As best shown in  FIG. 9 , the sealing surface  212  of the finish portion  164  is surrounded by a thin-walled region  276 . In the case of lightweight preforms, such as the preform  160 , the thin-walled region  276  is susceptible to being damaged by contact with conventional blow-molding nozzles. In particular, outwardly-directed forces on the thin-walled region  276 , such as due to forcible contact between the surface  212  and a conventional nozzle or internal pressure during blow-molding the preform  160 , tends to damage the sealing surface  212  and/or cause stress-failures within the thin-walled region  276 . Such outwardly directed forces may be eliminated, however, by extending the shroud  372  over the exterior of the finish portion  164 . The shroud  372  is configured to counteract any outwardly directed forces acting on the finish portion  164  due to internal pressure applied to the preform  160  during stretching and/or blow-molding the preform  160  into the container  100 . In absence of a force differential across the thin-walled region  276  of the finish portion  164 , stress on the finish portion  164  is eliminated. As such, supporting the finish portion  164  by way of the shroud  372  facilitates using a greater internal pressure within the preform  160  during blow-molding without harming the thin-walled region  276  of the finish portion  164 . 
     In the embodiment of the nozzle  360  illustrated in  FIGS. 8-9 , a tapered tip  380  is disposed forward of the cylindrical portion  364 . The tapered tip  380  comprises a decrease in the diameter of the cylindrical portion  364  that is configured to further accommodate the stepped interior of the preform  160 . As shown in  FIG. 9 , the tapered tip  380  generally provides clearance between the cylindrical portion  364  and the narrowing interior diameter of the surfaces  212 ,  220 ,  248  within the finish portion  164 . The tapered tip  380  is not limited to comprising a linearly tapering diameter of the cylindrical portion  364 , as shown in  FIG. 9 , but rather other shapes are contemplated. For example, in one embodiment, the tapered tip  380  comprises an inwardly rounded portion of the cylindrical portion  364  that is configured to prevent damage to the mirror-polished surfaces inside the finish portion  164  during insertion of the nozzle  360  into the preform  160 . In some embodiments, however, the tapered tip  380  may be omitted from the nozzle  360 , without limitation. 
       FIGS. 10-11  illustrate an exemplary embodiment of a nozzle  400  for blow-molding the preform  160  into a container, such as the abovementioned container  100 . The nozzle  400  is shown inserted into the finish portion  164 , parallel to the longitudinal axis  266 , and engaged with the stepped interior of the preform  160 . The nozzle  400  comprises a cylindrical portion  404  that may be coupled with other blow-molding equipment  262 . The cylindrical portion  404  includes a seal  408  that is configured to tightly engage with a shelf  402  disposed in the interior surface of the finish portion  164  of the preform  160 . The nozzle  400  includes an opening  412  whereby instruments may be inserted into the preform  160  for stretching and/or blow-molding the preform  160  into the container  100 . The seal  408  is disposed around the circumference of the cylindrical portion  404  and configured to tightly press against the shelf  402  without damaging the surfaces  212 ,  220  or the sidewall of the finish portion  164 . As such, it is contemplated that the preform  160  may be pressed onto the nozzle  400  during stretching and/or blow-molding the preform  160  to form the container  100 . 
     As best shown in  FIG. 11 , the shelf  402  includes a profile shape  406  that is generally squared, or right-angled. Accordingly, the seal  408  includes a squared periphery  410  that is disposed circumferentially around the seal  408 , such that the seal  408  may be tightly engaged with the profile shape  406  of the shelf  402  during stretching and/or blow-molding the preform  160  to form the container  100 . It is contemplated, however, that the seal  408  is not to be limited to the configuration shown in  FIG. 11 , but rather the seal  408  may comprise any of various configurations capable of engaging with various configurations of the shelf  402 . For example, in some embodiments, the seal  408  may be an O-ring configured to be received by a concaved profile shape of the shelf  402 . Further, the seal  408  may include a washer, a band, or an edge portion of the cylindrical portion  404  comprised of a material suitable for tightly sealing with the shelf  402  without damaging the interior surfaces of the finish portion  164 . The material comprising the seal  408  may be any material that is generally suitable for sealing with the PET comprising the preform  160 , such as, by way of non-limiting example, rubber, silicone, relatively softer PET that the PET comprising the preform  160 , any combination thereof, and the like. 
     With continuing reference to  FIGS. 10-11 , the seal  408  is configured to be pressed against the shelf  402  such that the force of contact is directed parallel to the longitudinal axis  266  and along the sidewall of the finish portion  164 . As will be appreciated, orienting the contact force parallel to the sidewall of the finish portion  164  allows for tighter sealing between the nozzle  400  and the preform  160 . Further, the force is distributed throughout an area of contact between the seal  408  and the shelf  402 . As such, the total pressure exerted on the finish portion  164  by the nozzle  400  is lower than the total pressure exerted by conventional nozzles that include O-rings. Those skilled in the art will appreciate that reducing the total pressure exerted on the finish portion  164  facilitates utilizing greater internal pressures within the preform  160  without cracking the thin-walled region  276  of the finish portion  164  during stretching and/or blow-molding the preform  160  to form the container  100 . 
     In some embodiments, the nozzle  400  may be configured to engage the top-most surface  242  of the preform  160 , as shown in  FIGS. 10-11 . In the illustrated embodiment, a sealing surface  424 , comprising the blow-molding equipment  262  and surrounding the nozzle  400 , may be configured to be tightly pressed against the top-most surface  242  with a degree of force capable of maintaining a suitable pressure inside the preform  160  for blow-molding without undesirably compressing the neck portion  192 . As best shown in  FIG. 11 , the sealing surface  424  may comprise a ring-shaped protrusion having a circumference suitable for contacting the entire circumference of the top-most surface  242  of the finish portion  164 . It is contemplated, however, that in some embodiments contact between the sealing surface  424  and the top-most surface  242  may be omitted due to the seal  408  being engaged with the shelf  402 , as described herein. As will be appreciated, engaging the seal  408  with the shelf  402  obviates any need for sealing the top-most surface  242  of the preform  160 . 
     Similar to the nozzle  360  of  FIGS. 8-9 , the nozzle  400  includes an exterior shroud  420  that is configured to extend over the threads  180  of the finish surface  164 . The shroud  420  generally is a cylindrical member having an inner diameter suitable for extending over the exterior of the finish portion  164  without damaging the threads  180 . The shroud  420  is configured to provide support to the finish portion  164  during stretching and/or blow-molding the preform  160  to form the container  100 , as described herein. 
     As described hereinabove, the thin-walled region  276  surrounding the sealing surface  212  of lightweight preforms, such as the preform  160 , is susceptible to being damaged by contact with conventional blow-molding nozzles. Outward forces on the thin-walled region  276 , due to forcible contact between the sealing surface  212  and a conventional nozzle or internal pressure during blow-molding the preform  160 , tends to damage the sealing surface  212  and/or cause stress-failures within the thin-walled region  276 . The nozzle  400  eliminates such outwardly directed forces, however, by extending the shroud  420  over the exterior of the finish portion  164 , in addition to engaging seal  408  with the shelf  402  inside the finish portion  164 . As will be appreciated, pressing the seal  408  against the shelf  402  directs most of the contact force along the sidewall of the finish portion  164 , parallel with the longitudinal axis  266 . At the same time, the shroud  420  counteracts any outwardly directed force components that may arise during stretching and/or blow-molding the preform  160  to form the container  100 . As such, supporting the finish portion  164  by way of the shroud  420  and sealing the preform by way of the shelf  402  facilitates using a greater internal pressure within the preform  160  without harming the thin-walled region  276  of the finish portion  164 . 
       FIGS. 12-13  illustrate an exemplary embodiment of a nozzle  440  for blow-molding the preform  160  of  FIG. 3  into a container, such as the container  100 . Similar to the nozzles described hereinabove, the nozzle  440  is configured to be inserted into the finish portion  164 , parallel to the longitudinal axis  266  of the preform  160  and engaged with the stepped interior of the preform  160 . The nozzle  440  comprises a cylindrical portion  444  that may be coupled with other blow-molding equipment  262  and includes a tapered tip  448  to tightly engage with the transition surface  216  of the finish portion  164  of the preform  160 . The nozzle  440  includes an opening  452  whereby instruments may be inserted into the preform  160  for stretching and/or blow-molding the preform  160  into the container  100 . The tapered tip  448  is disposed around the circumference of the cylindrical portion  444  and configured to tightly press against the transition surface  216  without damaging the surfaces  212 ,  220  or the sidewall of the finish portion  164 . 
     As best shown in  FIG. 13 , the tapered tip  448  extends to and terminates at a circular edge  460  that is configured to forcibly contact the transition surface  216  of the finish portion  164 . Preferably, the circular edge  460  has a diameter suitable to contact the transition surface  216  while providing clearance between the cylindrical portion  444  and the sealing surface  212 . Upon the nozzle  440  being inserted into the finish portion  164 , the circular edge  460  digs into the material comprising the transition surface  216  and thereby establishes a tight seal between the nozzle  440  and the interior of the preform  160 . As such, it is contemplated that the circular edge  460  may be sharpened or remain blunt, as desired. Further, the cylindrical portion  444  generally, and the circular edge  460  in particular may comprise any rigid material suitable for digging into the material comprising the transition surface  216 . 
     In general, the circular edge  460  of the tapered tip  448  is configured to be pressed against the transition surface  216  such that the force of contact is directed parallel to the longitudinal axis  266 , along the sidewall of the finish portion  164 . As described hereinabove, directing the contact force parallel to the sidewall of the finish portion  164  allows for tighter sealing between the nozzle  440  and the preform  160 , thereby facilitating greater internal pressures within the preform  160  without cracking the thin-walled region  276  of the finish portion  164  during stretching and/or blow-molding the preform  160  to form the container  100 . Further, the nozzle  440  includes an exterior shroud  464  configured to extend over the threads  180  of the finish surface  164 . The shroud  464  is a cylindrical member having an inner diameter suitable for extending over the threads  180  and configured to support the finish portion  164  during stretching and/or blow-molding the preform  160  to form the container  100 , as described herein. 
     As described hereinabove, the thin-walled region  276  surrounding the sealing surface  212  of lightweight preforms, such as the preform  160 , is susceptible to being damaged by contact with conventional blow-molding nozzles. Outward forces on the thin-walled region  276 , due to forcible contact between the surface  212  and a conventional nozzle or internal pressure during blow-molding the preform  160 , tends to damage the sealing surface  212  and/or cause stress-failures within the thin-walled region  276 . The nozzle  440  eliminates such outwardly directed forces by supporting the finish portion  164  with the exterior shroud  464  in addition to engaging tapered tip  448  with the transition surface  216  inside the finish portion  164 . As will be appreciated, combining exterior support of the finish portion  164  with sealing against the transition surface  216  counteracts any outwardly directed force components that may arise during stretching and/or blow-molding the preform  160  to form the container  100 . As such, a greater internal pressure within the preform  160  may be used to form the container  100  without harming the thin-walled region  276  of the finish portion  164 . 
     It is to be understood, however, that the nozzle  440  is not limited to engaging the transition surface  216 . For example, in some embodiments, the circular edge  460  of the tapered tip  448  may be configured to forcibly contact the secondary transition surface  244  while providing clearance between the cylindrical portion  444  and both the sealing and handling surfaces  212 ,  220 . In such embodiments, the circular edge  460  may be configured to dig into the material comprising the secondary transition surface  244 , such that a tight seal is established between the nozzle  440  and the interior of the preform  160  while the force of contact is directed parallel to the longitudinal axis  266 , as described herein. 
     In some embodiments, the nozzle  440  may be configured to engage the top-most surface  242  of the preform  160 , as shown in  FIGS. 12-13 . In the illustrated embodiment, a sealing surface  456 , comprising the blow-molding equipment  262  and surrounding the nozzle  440 , may be configured to be tightly pressed against the top-most surface  242  with a degree of force capable of maintaining a suitable pressure inside the preform  160  for blow-molding without undesirably compressing the neck portion  192 . As best shown in  FIG. 13 , the sealing surface  456  may comprise a ring-shaped protrusion having a circumference suitable for contacting the entire circumference of the top-most surface  242  of the finish portion  164 . It is contemplated, however, that in some embodiments contact between the sealing surface  456  and the top-most surface  242  may be omitted due to the circular edge  460  of the tapered tip  448  being engaged with the transition surface  216  or the secondary transition surface  244 , as described herein. As such, engaging the circular edge  460  with either of the transition surfaces  216 ,  244  obviates any need for sealing the top-most surface  242  of the preform  160 . 
     While the invention has been described in terms of particular variations and illustrative figures, those of ordinary skill in the art will recognize that the invention is not limited to the variations or figures described. In addition, where methods and steps described above indicate certain events occurring in certain order, those of ordinary skill in the art will recognize that the ordering of certain steps may be modified and that such modifications are in accordance with the variations of the invention. Additionally, certain of the steps may be performed concurrently in a parallel process when possible, as well as performed sequentially as described above. To the extent there are variations of the invention, which are within the spirit of the disclosure or equivalent to the inventions found in the claims, it is the intent that this patent will cover those variations as well. Therefore, the present disclosure is to be understood as not limited by the specific embodiments described herein, but only by scope of the appended claims.