Patent Publication Number: US-8528760-B2

Title: Lightweight container having mid-body grip

Description:
TECHNICAL FIELD 
     This disclosure generally relates to plastic containers for retaining a commodity, such as a solid or liquid commodity. More specifically, this disclosure relates to a one-piece blown container having mid-body grip. 
     BACKGROUND 
     As a result of environmental and other concerns, plastic containers, more specifically polyester and even more specifically polyethylene terephthalate (PET) containers, are now being used more than ever to package numerous commodities previously supplied in glass containers. Manufacturers and fillers, as well as consumers, have recognized that PET containers are lightweight, inexpensive, recyclable and manufacturable in large quantities. 
     Blow-molded plastic containers have become commonplace in packaging numerous commodities. PET is a crystallizable polymer, meaning that it is available in an amorphous form or a semi-crystalline form. The ability of a PET container to maintain its material integrity relates to the percentage of the PET container in crystalline form, also known as the “crystallinity” of the PET container. The following equation defines the percentage of crystallinity as a volume fraction: 
               %   ⁢           ⁢   Crystallinity     =       (       ρ   -     ρ   a           ρ   c     -     ρ   a         )     ×   100           
where ρ is the density of the PET material; ρ a  is the density of pure amorphous PET material (1.333 g/cc); and ρ c  is the density of pure crystalline material (1.455 g/cc).
 
     Container manufacturers use mechanical processing and thermal processing to increase the PET polymer crystallinity of a container. Mechanical processing involves orienting the amorphous material to achieve strain hardening. This processing commonly involves stretching an injection molded PET preform along a longitudinal axis and expanding the PET preform along a transverse or radial axis to form a PET container. The combination promotes what manufacturers define as biaxial orientation of the molecular structure in the container. Manufacturers of PET containers currently use mechanical processing to produce PET containers having approximately 20% crystallinity in the container&#39;s sidewall. 
     Thermal processing involves heating the material (either amorphous or semi-crystalline) to promote crystal growth. On amorphous material, thermal processing of PET material results in a spherulitic morphology that interferes with the transmission of light. In other words, the resulting crystalline material is opaque, and thus, generally undesirable. Used after mechanical processing, however, thermal processing results in higher crystallinity and excellent clarity for those portions of the container having biaxial molecular orientation. The thermal processing of an oriented PET container, which is known as heat setting, typically includes blow molding a PET preform against a mold heated to a temperature of approximately 250° F.-350° F. (approximately 121° C.-177° C.), and holding the blown container against the heated mold for approximately two (2) to five (5) seconds. Manufacturers of PET juice bottles, which must be hot-filled at approximately 185° F. (85° C.), currently use heat setting to produce PET bottles having an overall crystallinity in the range of approximately 25%-35%. 
     In some instances, it may be desirable to provide a user a grasping area on the container at which a user may engage and firmly hold the container. In one example, a container may define a handle near an upper shoulder of the container whereby a user can pass fingers or a thumb through an adjacent passage formed through the container to grasp the container. Such a configuration may be provided on a milk container for example. In other examples, it may be desirable to define a gripping portion integral with the body of the container. Furthermore, it is desirable to provide a gripping portion that contributes to the overall structural integrity of the container. 
     SUMMARY 
     Accordingly, the present disclosure provides a one-piece plastic container having a body defining a generally rectangular horizontal cross-section and including a first pair of opposing sidewalls and a second pair of opposing sidewalls. The body has an upper portion, a shoulder region, a sidewall portion and a base. The shoulder region is integrally formed with and extends from the upper portion to the sidewall portion. The base closes off an end of the container. The shoulder region defines a pair of grip portions defined in part by a respective pair of pillars. Each pillar defines oppositely facing walls that are offset inboard relative to the respective second pair of opposing sidewalls. 
     According to additional features, each grip portion is further defined by a pair of arched inset walls that transition from the second pair of opposing sidewalls, respectively to the pillars. In one example, each oppositely facing wall defines a substantially 90° angle relative to an adjacent arched inset wall at a horizontal cross-section taken through the shoulder region. Each pillar can define at least one horizontal rib and land formed thereon. According to still other features, a first and a second arched rib are defined on each of the second pair of opposing sidewalls. The first and second arched ribs cooperate to form a substantially oval geometry. The base may define an octagonal shape having a generally octagonal footprint. The shoulder portion defines a shoulder face. The pair of pillars define substantially about 20%-40% of the shoulder face. The shoulder portion can define a grip panel area at the second pair of opposing sidewalls. 
     Additional benefits and advantages of the present disclosure will become apparent to those skilled in the art to which the present disclosure relates from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a one-piece plastic container constructed in accordance with the teachings of the present disclosure. 
         FIG. 2  is a front elevational view of the container of  FIG. 1 . 
         FIG. 3  is a side elevational view of the container of  FIG. 1 . 
         FIG. 4  is a sectional view of the container taken along line  4 - 4  of  FIG. 2 . 
         FIG. 5  is a sectional view of the container taken along line  5 - 5  of  FIG. 2 . 
         FIG. 6  is a bottom view of the container of  FIG. 1 ; and 
         FIG. 7  is a sectional view of an exemplary mold cavity used during formation of the container of  FIG. 1  and shown with a preform positioned therein. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature, and is in no way intended to limit the disclosure or its application or uses. 
       FIGS. 1-6  show one preferred embodiment of the present container. In the Figures, reference number  10  designates a one-piece plastic, e.g., polyethylene terephthalate (PET), hot-fillable container. As shown in  FIG. 2 , the container  10  has an overall height A of about 262.28 mm (10.33 inches). As best shown in  FIGS. 1 and 4 , the container  10  is substantially rectangular in cross sectional shape including first sides  12  each having a width B ( FIG. 3 ), and opposing second sides  14  each having a width C ( FIG. 2 ). In the example shown, the first sides  12  are shorter than the second sides  14 . Opposing first sides  12  may be oriented at approximately 90-degree angles to the second sides  14  so as to form the generally rectangular cross section as shown in  FIG. 4 . The width B is about 93.99 mm (3.7 inches). The width C is about 119.00 mm (4.69 inches). The widths B and/or C may be selected so that the container  10  can fit within the door shelf of a refrigerator. In this particular example, the container  10  has a volume capacity of about 46 fl. oz. (1360 cc) to about 96 fl. oz. (2839 cc), and more preferably about 64 fl. oz. (1893 cc). Those of ordinary skill in the art would appreciate that the following teachings of the present invention are applicable to other containers, such as cylindrical, triangular, hexagonal, octagonal or square shaped containers, which may have different dimensions and volume capacities. It is also contemplated that other modifications can be made depending on the specific application and environmental requirements. 
     As shown in  FIGS. 1-4 , the one-piece plastic container  10  according to the present teachings defines a body  16  and includes an upper portion  18  having a finish  20 . Integrally formed with the finish  20  and extending downward therefrom is a shoulder region  22 . The body  16  can further define a mid-body  23  at the shoulder region  22 . The shoulder region  22  merges into and provides a transition between the finish  20  and a sidewall portion  24 . A grip panel area  25  can be provided at the mid-body  23 . The sidewall portion  24  extends downward from the shoulder region  22  to a base portion  26  having a base  28 . The exemplary container  10  may also have a neck  29  ( FIG. 2 ). The neck  29  may have an extremely short height, that is, becoming a short extension from the finish  20 , or an elongated height, extending from the finish  20  and the shoulder region  22 . 
     The shoulder region  22  defines a pair of grip portions  30 A and  30 B at the mid-body  23 . The construction of the grip portions  30 A and  30 B of the container  10  allows the shoulder region  22  to provide increased rigidity and structural support to the container  10 . The base  28  functions to close off the bottom portion of the container  10  and, together with the finish  20 , the shoulder region  22  and the sidewall portion  24 , to retain the commodity. 
     With specific reference now to  FIGS. 1 and 2 , the finish  20  defines an opening  32 . The finish  20  of the plastic container  10  may include a threaded region  33  having threads  34 , and a support ring  35 . The threaded region  33  provides a means for attachment of a similarly threaded closure or cap (not illustrated). Alternatives may include other suitable devices that engage the finish  20  of the plastic container  10 . Accordingly, the closure or cap (not illustrated) engages the finish  20  to preferably provide a hermetical seal of the plastic container  10 . The closure or cap (not illustrated) is preferably of a plastic or metal material conventional to the closure industry and suitable for subsequent thermal processing, including high temperature pasteurization and retort. The support ring  35  may be used to carry or orient a preform P ( FIG. 7 ) through and at various stages of manufacture. For example, the preform P may be carried by the support ring  35 , the support ring  35  may be used to aid in positioning the preform P in the mold, or an end consumer may use the support ring  35  to carry the plastic container  10  once manufactured. 
     The sidewall portion  24  further includes a series of horizontal ribs  36 . Horizontal ribs  36  are uninterrupted and circumscribe the entire perimeter of the sidewall portion  24  of the container  10 . Horizontal ribs  36  extend continuously in a longitudinal direction from the shoulder region  22  to the base  28 . Defined between each adjacent horizontal rib  36  are lands  38 . Lands  38  provide additional structural support and rigidity to the sidewall portion  24  of the container  10 . 
     The mid-body  23  can define a first and a second arched rib  40  and  42 , respectively ( FIGS. 1 and 2 ). The arched ribs  40  and  42  can cooperate to define an oval shape at the grip panel area  25 . The arched ribs  40  and  42  are generally stiff and provide increased structural support to the container  10  at the mid-body  23 . The grip panel area  25  is intended to be the primary grip area for the container  10 . The grip panel area  25  may be enhanced by creating a grip ledge introduced above the grip panel area  25  and/or profiling the width of the pillars  50  to an appropriate width for consumer handling. 
     Each grip portion  30 A and  30 B also may include horizontal ribs  46  ( FIG. 3 ). Defined between each adjacent horizontal rib  46  are lands  48 . Lands  48  provide additional structural support and rigidity to the grip portions  30 A and  30 B of the container  10 . It should be understood that although only three horizontally extending lands  48  are illustrated, a series of horizontal lands  48  having varying lengths may be used. 
     With reference now to all of the Figures, the grip portion  30 A will be described in greater detail. For simplicity, only the grip portion  30 A will be described in detail; however, it will be appreciated that the grip portion  30 B is constructed similarly. In general, the grip portion  30 A is defined by a generally vertical pillar  50  having a pair of oppositely facing walls  52  ( FIG. 2 ). The pair of oppositely facing walls  52  are generally inset relative to the opposing second sides  14  (see  FIG. 5 ). The opposing second sides  14  transition to the vertical pillars  50  through a pair of arched inset walls  54 . In one example, the vertical pillars  50  define 20%-40% of a face  56  ( FIG. 3 ) of the shoulder region  22 . As best shown in  FIG. 5 , the oppositely facing walls  52  and the inset walls  54  can define an angle α, such as 90 degrees, at the pillar  50 . Other angles are contemplated. Such a configuration can provide a favorable customer handling point. Furthermore, the pillars  50  can evenly distribute vertical loads from the neck  29  to the body  16 . The pillars  50  also provide a vertical structural component, which yields excellent top load strength capabilities. 
     After being filled with a hot product, capped and cooled, the product within the container  10  decreases in volume. This reduction in volume produces a reduction in pressure or a vacuum. The grip panel area  25  of the container  10  controllably accommodates this pressure reduction or vacuum by being capable of pulling inward, under the influence of the reduced pressure or vacuum, as shown in phantom lines in  FIG. 5 . The overall large dimension of the grip panel area  25  facilitates the ability of the grip panel area  25  to accommodate a significant amount of the reduced pressure or vacuum. 
     As the grip panel area  25  contracts inward, the more rigid horizontal lands  48  of each grip portion  30 A and  30 B deflect radially outward, providing a more linear or bowed outward orientation. This phenomenon is also shown in phantom lines in  FIG. 5 . Additionally, when a force is applied to the top of an empty container  10 , grip panel area  25  is caused to contract inwards. This in turn causes the more rigid horizontal lands  48  to deflect radially outward, assuming a more linear or bowed outward orientation enhancing resistance to the applied force. Moreover, oppositely facing walls  52  and arched inset walls  54  provide and act as a hinge, facilitating the movement of the grip panel area  25  and the horizontal lands  48 . 
     The grip portion  30 A (and  30 B) has been configured to define a geometry convenient for a consumer to grasp and hold the container  10 . In one exemplary method of grasping the container  10 , a consumer may wrap a hand around the first sides  12  at the grip portion  30 A, such that a thumb engages one of the oppositely facing walls  52  formed on one of the pillars  50  and the remaining fingers engage the other of the oppositely facing walls  52  formed on the pillar  50 . Because the arched inset walls  54  form a curved transition into the grip portion  30 A, a consumer is offered directional guidance toward the oppositely facings walls  52  for improved leverage during gripping for better control and feel of the container  10 . 
     The resultant geometrical configuration of the mid-body  23  provides improved localized strength at the grip portions  30 A and  30 B as well as creates a geometrically rigid structure. The resulting localized strength increases the resistance to creasing, buckling, denting, bowing and sagging of the shoulder region  22 , the sidewall portion  24  and the container  10  as a whole during filling, packaging and shipping operations. Specifically, the resultant localized strength aids in preventing deformation during hot fill. As such, fillers are able to fill the container  10  quicker since the container  10  is able to withstand the additional pressures associated with faster filling speeds. 
     With reference now to  FIG. 6 , the base  28  will be further described. The base  28  generally defines an octagonal shape creating a generally octagonal footprint and having sides  60 A- 60 H. The base  28  generally includes a contact surface  62  and a circular push up  64 . The contact surface  62  is itself that portion of the base  28  that contacts a support surface that in turn supports the container  10 . As such, the contact surface  62  may be a flat surface or line of contact generally circumscribing, continuously or intermittently, the base  28 . In one embodiment, as illustrated in  FIG. 6 , the contact surface  62  is a uniform, generally octagonal shaped surface that provides a greater area of contact with the support surface, thus promoting greater container stability. The circular push up  64  is generally centrally located in the base  28 . Because the circular push up  64  is centrally located in the base  28 , there is no need to further orient the container  10  in the mold. Thus promoting ease of manufacture. 
     Returning now to  FIGS. 2 and 3 , additional exemplary dimensions for the container  10  will be described. A height D of the finish  20  may be 18.31 mm (0.72 inch). A height E of the neck  29  may be 4.7 mm (0.19 inch). A height F of the shoulder region  22  taken from the support ring  35  to the sidewall portion  24  may be 117.22 mm (4.62 inches). A height G of the sidewall portion  24  may be 95 mm (3.74 inches). A height H of the base portion  26  may be 31.75 mm (1.25 inches). As shown in  FIG. 3 , a width I at the mid-body  23  may be 81.2 mm (3.20 inches). It is appreciated that these dimensions are merely exemplary and other dimensions may be used. 
     As explained above, the plastic container  10  has been designed to retain a commodity. The commodity may be in any form such as a solid or liquid product. In one example, a liquid commodity may be introduced into the container during a thermal process, typically a hot-fill process. For hot-fill bottling applications, bottlers generally fill the container  10  with a liquid or product at an elevated temperature between approximately 155° F. to 205° F. (approximately 68° C. to 96° C.) and seal the container  10  with a closure (not illustrated) before cooling. In addition, the plastic container  10  may be suitable for other high-temperature pasteurization or retort filling processes or other thermal processes as well. In another example, the commodity may be introduced into the container under ambient temperatures. 
     The plastic container  10  of the present invention is a blow molded, biaxially oriented container with a unitary construction from a single or multi-layer material. A well-known stretch-molding, heat-setting process for making the one-piece plastic container  10  generally involves the manufacture of the preform P ( FIG. 7 ) of a polyester material, such as polyethylene terephthalate (PET), having a shape well known to those skilled in the art similar to a test-tube with a generally cylindrical cross section and a length typically approximately fifty percent (50%) that of the container height. 
     Turning now to  FIG. 7 , an exemplary method of forming the container  10  will be described. At the outset, the preform P may be placed into a mold cavity  90 . In general, the mold cavity  90  has an interior surface corresponding to a desired outer profile of the blown container. More specifically, the mold cavity  90  according to the present teachings defines a body forming region  92 , including a grip forming region  94 . In one example, a machine (not illustrated) places the preform P heated to a temperature between approximately 190° F. to 250° F. (approximately 88° C. to 121° C.) into the mold cavity  90 . The mold cavity  90  may be heated to a temperature between approximately 250° F. to 350° F. (approximately 121 ° C. to 1 77° C.). A stretch rod apparatus (not illustrated) stretches or extends the heated preform P within the mold cavity  90  to a length approximately that of the end container  10  thereby molecularly orienting the polyester material in an axial direction generally corresponding with a central longitudinal axis  96  of the preform P and the resultant container  10 . While the stretch rod extends the preform P, air having a pressure between 300 PSI to 600 PSI (2.07 MPa to 4.14 MPa) assists in extending the preform P in the axial direction and in expanding the preform P in a circumferential or hoop direction thereby substantially conforming the polyester material to the shape of the mold cavity  90  and further molecularly orienting the polyester material in a direction generally perpendicular to the axial direction, thus establishing the biaxial molecular orientation of the polyester material in the container  10 . The pressurized air holds the mostly biaxial molecularly oriented polyester material against the mold cavity  90  for a period of approximately two (2) to five (5) seconds before removal of the container  10  from the mold cavity  90 . 
     Alternatively, other manufacturing methods using other conventional materials including, for example, polypropylene, high-density polyethylene, polyethylene naphthalate (PEN), a PET/PEN blend or copolymer, and various multilayer structures may be suitable for the manufacture of the container  10 . Those having ordinary skill in the art will readily know and understand plastic container manufacturing method alternatives. 
     While the above description constitutes the present disclosure, it will be appreciated that the disclosure is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.