Patent Publication Number: US-2019193924-A1

Title: Structure and method of sealing a closure assembly onto the neck finish of a plastic pressure container

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/726,736, filed Oct. 6, 2017, which is a continuation of U.S. patent application Ser. No. 15/088,977, filed Apr. 1, 2016, now U.S. Pat. No. 9,845,186, which claims priority to U.S. Provisional Application No. 62/141,647, filed Apr. 1, 2015, all of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     Field of Disclosed Subject Matter 
     The disclosed subject matter relates generally to containers adapted to hold pressurized contents, for example aerosol mixtures. The disclosed structures and methods can be used for sealing a closure assembly onto the neck finish of a plastic pressure container. 
     Description of Related Art 
     Pressure containers can be used to store and dispense pressurized contents, such as aerosol mixtures and carbonated beverages or the like. Pressure containers commonly must be capable of withstanding internal pressures of the magnitude of 40-200 psi. Accordingly, metal containers having a cylindrical tube and upper and lower ends have been used for pressure containers. However, metallic containers have certain disadvantages, such as a tendency to rust over time and to scratch surfaces with which the metal containers may come into contact. 
     Attempts have been made to develop plastic pressure containers. However, the high internal pressures for pressure containers is significantly greater than pressures that are typically encountered in other packaging applications for which plastic material has been used, such as the packaging for unpressurized liquids. Accordingly, design considerations for plastic pressure containers are significantly different than for lower pressure packaging applications such as plastic beverage containers. An example of a plastic pressure container for storing and dispensing an aerosol mixture is provided in U.S. application Ser. No. 13/251,830, which is incorporated herein in its entirety. 
     As such, there is a continued need for a blow molded plastic pressure container assembly that provides an effective mount and seal between the finish portion of the plastic container and the closure assembly. The present disclosure satisfies these and other needs. 
     SUMMARY 
     The purpose and advantages of the disclosed subject matter will be set forth in and apparent from the description that follows, as well as will be learned by practice of the disclosed subject matter. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof, as well as from the appended drawings. 
     To achieve these and other advantages and in accordance with the purpose of the disclosed subject matter, as embodied and broadly described, the disclosed subject matter provides a plastic pressure container. The container includes a main body portion, a finish portion and a closure assembly. The main body portion defines an interior space. The finish portion is unitary with the main body portion and defines a mouth in communication with the interior space. The finish portion includes an inner surface, an outer surface, and an upper rim proximate the mouth. The inner surface has an inner undercut defined therein proximate the upper rim. The outer surface has an outer undercut defined therein proximate the upper rim. The closure assembly is mounted to the finish portion in engagement with both the inner undercut and the outer undercut. 
     As embodied herein, the main body portion and finish portion can be fabricated from a material comprising polyethylene terephthalate. Alternatively, and as embodied herein, the main body portion and finish portion can be fabricated from polyethylene naphthalate (PEN), polyethylene furanoate (PEF), or other polyester based polymers. The inner undercut can extend substantially along an entire inner circumference of the inner surface of the finish portion. The outer undercut can extend substantially along an entire outer circumference of the outer surface of the finish portion. 
     As embodied herein, the plastic pressure container can include a sealing member disposed between the finish portion and the closure assembly. The finish portion can include at least one rib. In some embodiments, the finish portion can include at least two ribs. The finish portion can define a longitudinal axis, and at least one of the inner undercut and the outer undercut can define an engagement surface that is substantially perpendicular to the longitudinal axis. The closure assembly can be mounted to the finish portion by a crimped engagement. The plastic pressure container can contain an aerosol mixture comprising a propellant. 
     It is to be understood that both the foregoing general description and the following detailed description and drawings are examples and are provided for purpose of illustration and not intended to limit the scope of the disclosed subject matter in any manner. 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to illustrate and provide a further understanding of the structure and method of the disclosed subject matter. Together with the description the drawings serve to explain the principles of the disclosed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter of the application will be more readily understood from the following detailed description when read in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a side view of an exemplary embodiment of a plastic pressure container having a main body portion, finish portion, and closure assembly as described above and claimed herein. It will be apparent that variations to the size and shape of the plastic pressure container can be provided. 
         FIG. 2  is an enlarged detail in cross-section side view of the finish portion and closure assembly (with valve omitted for clarity) of the plastic pressure container shown in  FIG. 1  prior to crimping the closure assembly onto the finish portion. 
         FIG. 3  is an enlarged cross-section view of the finish portion and closure assembly of the plastic pressure container shown in  FIG. 1  after crimping the closure assembly onto the finish portion. As shown in  FIG. 3 , the closure assembly is mounted to the finish portion in engagement with both the inner undercut and the outer undercut of the finish portion. 
         FIG. 4  is an enlarged detail in side view of the finish portion of the plastic pressure container, illustrating exemplary dimensions. 
         FIG. 5  is a cross-section view of the finish portion of the plastic pressure container, along line  5 - 5  in  FIG. 4 . The finish portion includes, as illustrated in  FIG. 5 , an inner surface having an inner undercut defined therein proximate the upper rim, and an outer surface having an outer undercut defined therein proximate the upper rim. Exemplary dimensions are illustrated. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments of the disclosed subject matter, an example of which is illustrated in the accompanying drawings. The disclosed subject matter will be described in conjunction with the detailed description of the system. 
     The disclosed subject matter provides improved sealing between a closure assembly and a finish portion of a plastic pressure container. The disclosed subject matter includes a hybrid sealing system, wherein the closure assembly can be crimped on both the inside and outside surfaces of a plastic neck finish. As such, the finish portion of a plastic pressure container is disposed between a sidewall of the closure assembly on both the inside and outside surfaces in order to secure the closure assembly to the finish portion on both surfaces of the finish portion. Such configuration thus provides multiple points of contact between the closure assembly and the finish portion of the plastic pressure container, thereby increasing the overall surface for engagement between the closure assembly and the finish portion. As embodied herein the closure assembly can be mounted on the plastic neck finish and in engagement therewith, for example, on both the inside and outside surfaces. 
     As embodied here, the plastic pressure container can be used to store and dispense a variety of liquid and gaseous components. The plastic pressure container can store and dispense pressurized components, for example components having pressures from about 40 psi to about 160 psi. By way of example, and as reference herein for illustration and not limitation, the plastic pressure container can include an aerosol mixture including a liquid propellant. In such applications, the plastic pressure container can be capable of withstanding pressures from about 80 psi to about 100 psi or greater (e.g., up to 160 psi). As further example, the plastic pressure container can include a carbonated liquid. In such applications, the plastic pressure container can be capable of withstanding pressures from about 40 psi to about 60 psi. 
     In accordance with one aspect the disclosed subject matter, a plastic pressure container is provided. The container includes a main body portion, a finish portion and a closure assembly. The main body portion defines an interior space. The finish portion is unitary with the main body portion and defines a mouth in communication with the interior space. The finish portion includes an inner surface, an outer surface, and an upper rim proximate the mouth. The inner surface has an inner undercut defined therein proximate the upper rim. The outer surface has an outer undercut defined therein proximate the upper rim. The closure assembly is mounted to the finish portion in engagement with both the inner undercut and the outer undercut. 
     Solely for purpose of illustration, an exemplary embodiment of a plastic pressure container is shown in  FIG. 1 . The examples herein are not intended to limit the scope of the disclosed subject matter in any manner. Particularly, and as illustrated, the plastic pressure container  10  includes a main body portion  12 , a finish portion  14 , and a closure assembly  24  for an aerosol product, wherein the closure assembly  24  includes a valve suitable for dispensing aerosol products is depicted. The plastic pressure container  10  further includes a bottom portion  18 , and can contain a variety of suitable contents  30  such as aerosol products and pressurized fluids, e.g., liquids or gaseous contents. 
     As embodied herein, the main body portion  12  defines an interior space within the plastic pressure container  10 . The interior space can create a chamber for holding suitable contents, such as aerosol products and pressurized fluids, e.g., liquid or gaseous contents  30 . 
     For example, the plastic pressure container embodied herein can include an aerosol mixture. The aerosol mixture preferably includes a propellant, which could be a liquefied gas propellant or a compressed or soluble gas propellant. Liquefied gas propellants that could be used include hydrocarbon propellants such as propane, isobutene, normal butane, isopentane, normal pentane and dimethyl ether, and hydrofluorocarbon propellants such as difluoroethane (HFC-152a), tetrafluoroethane (HFC-134a), and tetrafluoropropene (HFO-1234ze). Compressed and soluble gas propellants that could be used include carbon dioxide (CO 2 ), nitrous oxide (N 2 O), nitrogen (N 2 ) and compressed air. 
     Alternatively, the plastic pressure container can include other pressurized contents that do not include a propellant. For example, and not limitation, the plastic pressure container can hold a carbonated liquid, such a soft drink or beer, or a flavor concentrate. 
     As embodied herein, and as depicted in  FIG. 1 , the finish portion  14  can be unitary with the main body portion  12 . The finish portion  14  can define a mouth that is in communication within the interior space. For the purpose of further illustration, and not limitation,  FIGS. 2-5  provide additional views of the finish portion. 
     With reference to  FIGS. 2 and 3 , the finish portion includes an inner surface  20 , an outer surface  30 , and an upper rim  40  proximate the mouth. An inner undercut  22  is defined within the inner surface  20 . The inner undercut  22  is proximate the upper rim  40 . The inner undercut  22  can extend substantially along an entire inner circumference of the inner surface  20  of the finish portion  14 . The inner undercut  22  thus can define an inner diameter (e.g., as illustrated by diameter D 2  of  FIG. 5 ) below the upper rim  40 . The upper rim  40  can also define an inner diameter (e.g., as illustrated by diameter D 1  of  FIG. 5 ) proximate the mouth. As depicted in  FIGS. 2 and 3 , the inner diameter at the inner undercut  22  can be greater than the inner diameter at the upper rim  40 . 
     Additionally, as embodied herein, an outer undercut  32  is defined within the outer surface  30  of the finish portion  14 . The outer undercut  32  is proximate the upper rim  40 . The outer undercut  32  can extend substantially along an entire outer circumference of the outer surface  30  of the finish portion  14 , for example, as depicted in  FIG. 4 . 
       FIG. 5  provides a detailed view of the finish portion  14 , and depicts exemplary embodiments of the inner undercut  22  and the outer undercut  32 . As depicted in  FIG. 5 , the inner undercut  22  can be contoured or curved. The pronouncement or complexity of the contour of the inner undercut  22  can vary as needed. For example, as embodied herein, the contour of the inner undercut can be more linear or more curved than as depicted in  FIGS. 2-5 . With reference to  FIG. 5 , for purpose of illustration, an angle a of the inner undercut  22  can be defined by line x, which is tangential to the inner undercut. The angle a of the inner undercut  22  can be the angle between line x and a vertical line y. By way of example, angle a can range between a minimum of about 10° and a maximum of about 50°. 
     As embodied herein, the outer undercut  32  can be contoured or curved. Alternatively, the outer undercut can have a polygonal shape in cross-section, for example a triangular or rectangular shape. The dimension between the outer undercut  32  and the upper rim  40 , as defined by distance D 5  in  FIG. 5 , can be based on, for example, the configuration of the valve assembly  24 . In certain embodiments, this dimension is compatible with existing crimping systems and methods. 
     The depth of the inner undercut  22  and the outer undercut  32 , respectively, can be based on various design specification, including the pressure of the contents in the plastic pressure container, and the material and construction of the closure assembly. 
     For purpose of example, and not limitation, reference will be made to exemplary dimensions for a finish portion and pressure container as depicted in  FIG. 5 . For illustration, the exemplary dimensions will be based on a pressure container having a diameter D 1  of about 1 in. at the upper rim  40  and a maximum volume of about 1 L. Such a container is in accordance with industry standards, and thus could provide compatibility with existing manufacturing and packaging processes. However, this example is not intended to limit the scope of this disclosure, and a person of ordinary skill in the art would recognize that these techniques and dimensions can be adapted to various-sized pressure containers in accordance with the disclosed subject matter. 
     Ranges for selected dimensions depicted in  FIGS. 4 &amp; 5  are reproduced in Table 1 below. Table 1 also provides an Example embodiment to illustrate exemplary ratios between the various dimensions. In Table 1, the depth of the outer undercut is equal to one-half of the difference between outer diameter D 3  at the upper rim  40  and outer diameter D 4  at the outer undercut  32 . 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Exemplary dimensions of the finish portion. 
               
            
           
           
               
               
               
               
            
               
                 Dimension 
                 Minimum 
                 Maximum 
                 Example 
               
               
                   
               
               
                 Inner diameter at inner undercut (D2) 
                 1.020 in. 
                 1.120 in. 
                 1.084 in. 
               
               
                 Angle of inner undercut (a) 
                 10° 
                 50° 
                 35° 
               
               
                 Depth of outer undercut 
                 0.035 in. 
                 0.060 in. 
                 0.055 in. 
               
               
                 Distance between outer undercut and 
                 0.050 in. 
                 0.200 in. 
                 0.098 in. 
               
               
                 upper rim (D5) 
               
               
                   
               
            
           
         
       
     
     As embodied herein, the finish portion  14  can further include a flange  70  on the outer surface  30 . The flange  70  can be configured as a support ledge, which can be used for part transfer during manufacture and assembly of the finish portion and/or pressure container. The flange  70  can also provide extra strength and support to the assembled pressure container, e.g., by counteracting internal pressures within the container. 
     As embodied herein, the finish portion  14  can further include various features for fitting a removable lid or cap onto the plastic pressure container. By way of example the finish portion  14  can include one or more threads, clips, ribs, ridges, and the like for engagement with a removable lid or cap. 
     As embodied herein, the main body portion  12  and finish portion  14  can be fabricated from a material comprising polyethylene terephthalate. Alternatively, and as embodied herein, the main body portion and finish portion can be fabricated from polyethylene naphthalate (PEN), polyethylene furanoate (PEF), or other polyester based polymers. 
     With further reference to  FIG. 1 , the closure assembly  24  can include a valve  24 A or the like for dispensing contents. The closure assembly is mounted to the finish portion  14  of the plastic pressure container  10 .  FIGS. 2 and 3  provide detailed views of the engagement between the finish portion  14  and the closure assembly  24 .  FIG. 2  shows the engagement of the finish portion  14  and the closure assembly  24  prior to crimping, whereas  FIG. 3  shows the engagement of the two components after crimping. As depicted in  FIG. 3 , the closure assembly  24  is in engagement with both the inner undercut  22  and the outer undercut  32  of the finish portion  14 . 
     As embodied herein, for purpose of illustration only and not limitation, the closure assembly  24  can be a metal closure assembly, for example, a metal valve cup. As such, the encapsulated plastic of the finish portion  14  can have controlled deformation due to the metal boundary restricting both sides of the finish portion  14 . Further, the entire laminate structure (i.e., metal/plastic/metal) likewise will move in unison when exposed to high filling and service conditions. The laminate structure also provides strength to withstand stresses and strains from crimping and filling operations, and the hermetic seal created between the plastic and metal can be sufficiently stable to inhibit a pathway for leakage of the contents from the container. Alternatively or additionally, the closure or closure assembly can be a plastic closure assembly. For example, the closure or closure assembly can be wholly plastic, wholly metallic, or contain both plastic and metallic components. The closure or closure assembly can have any configuration features suitable for dispensing the aerosol product or pressurized fluid, e.g., gaseous or liquid contents, of the plastic pressure container. 
     In embodiments having a metal closure assembly, and with reference to  FIGS. 2 and 3 , the closure assembly  24  can include a metallic panel  50 . A valve stem (not depicted) can be mounted to the metallic panel  50 . The metallic panel  50  can include an annular downwardly extending portion  52  that includes an outer wall portion  54 , which is oriented so as to be substantially straight and vertical, permitting convenient insertion of the blank closure assembly  24  into the opening. The metallic panel  50  also preferably includes a flange portion  56  that is congruent with and seals against the upper rim  32  of the finish portion  14 . 
     The closure assembly  24  can be mounted to the finish portion by a crimped engagement. As depicted in  FIG. 3 , when crimped, the flange portion  56  is congruent with and engaged within both the inner undercut  22  and the outer undercut  32 . For example, the finish portion  14  can define a longitudinal axis, and at least one of the inner undercut  22  and the outer undercut  32  can define an engagement surface that is substantially perpendicular to the longitudinal axis. A variety of crimping techniques can be used to facilitate crimped engagement with both the inner undercut  22  and the outer undercut  32 , as described below. 
     As embodied herein, and with reference to  FIGS. 2 and 3 , the plastic pressure container can further include a sealing member  60  disposed between the finish portion  14  and the closure assembly  24 . The sealing member can be a gasket or an O-ring, and can be fabricated from Buna-N, neoprene, Viton, butyl, silicone, or other suitable materials. The finish portion  14  can optionally include at least one rib  62  extending along the surface against which the sealing member will engage. In some embodiments, for example, as depicted in  FIGS. 2 and 3 , the finish portion  14  can include at least two ribs  62 . The rib(s)  62  can be disposed on the upper rim  40  of the finish portion  14 . The rib(s)  62  can extend substantially along an entire circumference of the upper rim  40 . 
     As embodied herein, the plastic pressure container can be fabricated by any suitable method. In certain aspects, a method of sealing a closure assembly onto the neck finish of a plastic pressure container is provided. For example, the plastic pressure container can be fabricated by creating a perform by injection molding, where the preform includes the finish portion  14  having an inner undercut  22 , an outer undercut  32 , and, optionally, one or more ribs  62 . Because the finish portion  14  is configured to include both an inner undercut  22  and an outer undercut  32  for engagement with the closure assembly  24 , each undercut can be shallower (i.e., smaller undercut dimension) than if a single undercut were provided, yet still provide sufficient engagement surface. In this manner, the use of shallower undercut can simplify manufacturing of the finish portion  14  by injection molding. 
     Furthermore, the finish portion  14  of the preform can be crystallized to further strengthen the finish for engagement with the closure assembly. For example, the finish portion  14  can be crystallized using heat that is localized at only the finish portion of the preform. During crystallization, the inner undercut portion can be supported to maintain the geometry. For example, a plug can be inserted into the mouth of the finish portion  14  to provide support to the inner undercut  22  and maintain the inner diameter of the inner undercut  22 . As embodied herein, the plug can be provided in a single cylindrical to support the finish portion  14  at a location above the inner undercut  22 . Additionally, one or more pins can be used to support the outer undercut  32  during crystallization. 
     After the finish portion has been crystallized, the main body portion  12  can be blow molded to its final dimensions. With reference to  FIG. 1 , the main body portion  12  can be generally bottle shaped, or can have any alternative suitable shape. The main body portion  12  can be unitary with the finish portion  14  and can include a bottom portion  18 . 
     Once the main body portion  12  has been blow molded, the interior space can be filled with any suitable contents  30 , and the closure assembly  24  can be mounted onto the finish portion  14  and crimped to engage the closure assembly  24  with the finish portion  14 . With reference to  FIGS. 2 and 3 , a tool can be used to apply pressure to crimp the outer wall portion  54  of the closure assembly  24  outwardly into the position that is shown in  FIG. 3 , such that a portion of the outer wall portion  54  is seated securely against the inner undercut  22 . Additionally, the flange portion  56  can be crimped such that a portion of the flange portion  56  is seated securely against the outer undercut  32 . Thus, the closure assembly  24  can be mounted such that the closure assembly  24  is in engagement with both the inner undercut  22  and the outer undercut  32 . In this manner, the closure assembly  24  can be firmly secured against dislodgement from the finish portion  14  that could otherwise result from the internal pressurization of the container. 
     During crimping, pressure can be applied to both of the inner surface  20  and the outer surface  30  of the finish portion  14  in order to crimp the closure assembly  24  against both of the inner undercut  22  and outer undercut  32 . Therefore, during crimping, the finish portion  14  can be supported at both the inner surface  20  and the outer surface  30 . Providing support to both surfaces can reduce the amount of stress placed on the finish portion  14  during the crimping process and thus prevent or minimize cracking and deformation of the finish portion  14 . 
     While the disclosed subject matter is described herein in terms of certain preferred embodiments, those skilled in the art will recognize that various modifications and improvements can be made to the disclosed subject matter without departing from the scope thereof. Moreover, although individual features of one embodiment of the disclosed subject matter can be discussed herein or shown in the drawings of the one embodiment and not in other embodiments, it should be apparent that individual features of one embodiment can be combined with one or more features of another embodiment or features from a plurality of embodiments. 
     Each of the components described herein can be made of any suitable material (e.g., plastics, composites, metal, etc.) and technique for its intended purpose. In addition to the various embodiments depicted and claimed, the disclosed subject matter is also directed to other embodiments having any other possible combination of the features disclosed and claimed herein. As such, the particular features presented herein can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter includes any suitable combination of the features disclosed herein. Furthermore, although reference is made to a plastic pressure container throughout this disclosure, containers made of other suitable materials can likewise include the features disclosed herein. Similarly, the container need not be a pressure container, and the closure assembly can include a wide variety of suitable closures, such as a cap, lid, or other feature for dispensing the contents of the container. Thus, the foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the method and system of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents.