Abstract:
A lightweight polyester preform is disclosed for the production of light weight polyester containers by blow molding. The preforms and the resulting blown containers have threads on an exterior surface adjacent an upper end. Adjacent to and located below the threads is a support ring. The support ring is used in handling and conveying a preform from injection molding to a blow mold and in blow molding the container from the preform. It also is used in handling and conveying the preform from storage to the blow mold. To lightweight the preform, and subsequent container, the support ring is designed to have a minimum weight, but a sufficient strength for the handling of the preform in the production of the blow molded container. The support ring is reduced in weight by about 10% to about 70% from a conventional preform support ring.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Application 61/689,790 filed Jun. 12, 2012, the contents of which are incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to light weight preforms for the production of blow molded containers. More particularly, the invention is directed primarily to polyester container preforms where a part of the lightweight structure is a preform support ring of a decreased weight and a polyester material. The preform support rings have a structure which is solely sufficient to support the preform through handling and the blow molding of the preform to the container and subsequently handling the container through the use of a minimum amount of polyester material. 
       BACKGROUND 
       [0003]    There is an interest in producing containers with as low a weight as reasonably possible. An economic reason is to save on the amount of structural material in a container. This lowers the cost of the container and the overall cost of the product in the container. There additionally is a companion interest in using lightweight closures. In many countries there also is an ecological advantage in that an ecological tax is levied on the material content of a container and closure. Consequently, there is considerable attention given to the issue of container weight and the associated closure. They are designed to minimize weight thus costs. The extra weight in a blow molded container will usually be in the base and in the neck finish. The base must be sufficiently strong to support the filled container throughout filling, shipping and use. This includes the stacking of the containers whether within stacked cartons or stacked as individual containers. This is more so the case for containers for carbonated beverages. The neck finish must be sufficiently strong to withstand the filling and capping operations as well as subsequent shipping and use. This issue of decreasing the weight of blow molded containers has been approached in various ways. 
         [0004]    In U.S. Pat. No. 7,976,767 the preform is light weighted through the use of thinned neck finish areas that are molded into the preform at the time of injection molding the preform. The thicker areas will be sufficiently strong to provide a sufficient strength to the overall neck finish. This will compensate for a lack of strength in the thinned areas. U.S. Pat. No. 7,708,159 is directed to making containers with a lower center of gravity. This is accomplished by reducing the weight of the neck portion by decreasing its height and by making the tamper evident bead discontinuous. The primary objective is to lightweight the container. In U.S. Pat. No. 7,279,207 the container is light weighted by the container not having a neck finish to be sealed with a threaded closure, but rather by a flat seal, such as a foil seal. This significantly decreases the height of the neck finish and thus the weight of the container. However, such a container could not be used for carbonated beverages and in other uses where a substantial closure is needed. In US 2010/0116771 the increased light weight technique is to decrease the dimension of the neck sufficient to attach a closure using the support ring as a part of the tamper evident closure structure. This requires strengthening the support ring but may lower material content of the neck/spout. This will add weight to the support ring. In US 2011/0100946 a polyester container is light weighted by utilizing internal threads in order to decrease the linear dimension of the neck. There is a support ring that is used for the conventional purpose of handling the preform through the container blow molding process and the subsequent use of the support ring as a part of the container closure. When used as a part of the container closure the support ring in whole or in part secures the closure onto the container neck. This requires that the support ring have an added strength in order to provide for the two functions. It must be sufficient to support the preform through the blow molding process and when it is being removed from the mold as well as assist in sealing the container. Additionally, utilizing this technique closures threaded onto the exterior of the neck finish cannot be used. This includes the containers commonly used in the carbonated beverage industry, one of the larger users of blow molded containers. 
       SUMMARY 
       [0005]    The present invention is directed to reducing the amount of material in the support ring of the preform and thus of the resulting container. The support ring is engineered to dimensions and strength to handle the preform through the container blow molding process, but is not of dimensions and strength for other purposes such as to additionally be used as a part of the technique to close the container. That would require different dimensions and additional material. In the present invention the material of the support ring is reduced about 10% to about 70% from the support rings on various prior art containers. The total savings for the preform will depend also on other parts of the preform. This will include the thickness of the base portion and other parts of the finished container. Thus the only clear way to look at additional weight savings is through the weight savings of the preform alone. 
         [0006]    The invention comprises a lightweight thermoplastic preform for the production of lightweight thermoplastic containers comprising an elongated thermoplastic body having an open end and a closed end, the open end having an opening defined by a sidewall of the thermoplastic body, threads on an exterior surface of the sidewall adjacent the open end, a support surface located below the threads, the support surface extending a distance from the sidewall, the support surface having defined dimensions whereby the weight of the preform can be reduced about 10% to about 70% utilizing the defined dimensions. 
         [0007]    The defined dimensions of the support ring surface for the lightweight thermoplastic container can include a varied thickness of the support ring surface, a varied width of the support ring surface, a discontinuity of the support ring surface and void regions in the support ring surface. There also can be a combined utilization of one or more of a varied thickness, a varied width, discontinuity and void regions. This will reduce the material content and thus the weight of the support ring surface. 
         [0008]    When the defined dimensions include a support ring surface with a varied thickness there can be reinforcing segments on a lower surface of the support ring surface, on the upper surface of the support ring surface, or on both the lower and the upper surfaces of the support ring surface. In addition the reinforcing segments can comprise information such as a logo, product name or information as to the opening of the associated container or as to use of the product in the container. 
         [0009]    The lightweight thermoplastic preform can have an elongated thermoplastic body that is generally cylindrical having a circular cross-section or a polygonal cross-section of three or more sides. The threads are for the attachment of a closure to a container formed from the preform. 
         [0010]    The lightweight thermoplastic preform preferably is comprised of a polyester, a preferred polyester being a polyethylene terephthalate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of a preform with a lower elongated body, an open upper end, threads adjacent the open upper end and a support surface below the threads, the support surface containing voids. 
           [0012]      FIG. 2  is a side elevation view of the preform of  FIG. 1 . 
           [0013]      FIG. 3  is a vertical cross-section of the preform of  FIG. 1 . 
           [0014]      FIG. 4  is a top plan view of the preform of  FIG. 1 . 
           [0015]      FIG. 5  is a bottom plan view of the preform of  FIG. 1 . 
           [0016]      FIG. 6  is a cross-section view of the preform of  FIG. 2  along line  6 - 6  of  FIG. 2 . 
           [0017]      FIG. 7  is a first alternate embodiment of the preform of  FIG. 1  where there is a plurality of support surface reinforcements on an upper surface of the support surface. 
           [0018]      FIG. 8  is a bottom plan view of the preform of  FIG. 7 . 
           [0019]      FIG. 9  is a top plane view of the preform of  FIG. 7 . 
           [0020]      FIG. 10  is a second alternate embodiment of the preform of  FIG. 1  where there is a plurality of support surface reinforcements on a lower surface of the support surface. 
           [0021]      FIG. 11  is a bottom plan view of the preform of  FIG. 10 . 
           [0022]      FIG. 12  is a top plan view of the preform of  FIG. 10 . 
           [0023]      FIG. 13  is a third alternate embodiment of the preform of  FIG. 1  where there is a plurality of support surface reinforcements on a lower surface of the support surface. 
           [0024]      FIG. 11  is a bottom plan view of the preform of  FIG. 10 . 
           [0025]      FIG. 12  is a top plane view of the preform of  FIG. 10 . 
           [0026]      FIG. 13  is a fourth alternate embodiment of the preform of  FIG. 1  where the support surface is of a decreased width. 
           [0027]      FIG. 14  is a bottom plan view of the preform of  FIG. 13 . 
           [0028]      FIG. 15  is a top plane view of the preform of  FIG. 13 . 
           [0029]      FIG. 16  is a fifth alternate embodiment of the preform of  FIG. 1  where the support surface is comprised of a plurality of reinforced segments. 
           [0030]      FIG. 17  is a bottom plan view of the preform of  FIG. 16 . 
           [0031]      FIG. 18  is a top plane view of the preform of  FIG. 16 . 
           [0032]      FIG. 19  is a sixth alternate embodiment of the preform of  FIG. 1  where the support surface is reinforced with an embossed message. 
           [0033]      FIG. 20  is a bottom plan view of the preform of  FIG. 19 . 
           [0034]      FIG. 21  is a top plane view of the preform of  FIG. 19 . 
           [0035]      FIG. 22  is a seventh alternate embodiment of the preform of  FIG. 1  where the support surface contains a plurality of voids. 
           [0036]      FIG. 23  is a bottom plan view of the preform of  FIG. 22 . 
           [0037]      FIG. 24  is a top plane view of the preform of  FIG. 22 . 
           [0038]      FIG. 25  is an eight alternate embodiment of the preform of  FIG. 1  where the support surface has a varied width. 
           [0039]      FIG. 26  is a bottom plan view of the preform of  FIG. 25 . 
           [0040]      FIG. 27  is a top plan view of the preform of  FIG. 25 . 
           [0041]      FIG. 28  is a ninth alternate embodiment of the preform of  FIG. 1  where the support surface has an L-shape. 
           [0042]      FIG. 29  is a bottom plan view of the preform of  FIG. 28 . 
           [0043]      FIG. 30  is a top plan view of the preform of  FIG. 28 . 
           [0044]      FIG. 30A  is a cross-section of the support ring of  FIG. 28 . 
           [0045]      FIG. 31  is a tenth alternate embodiment of the preform of  FIG. 1  where the support surface has support segments. 
           [0046]      FIG. 32  is a bottom plan view of the preform of  FIG. 31 . 
           [0047]      FIG. 33  is a top plan view of the preform of  FIG. 31 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0048]    The invention will now be described in more detail in its preferred embodiments with reference to the attached drawings. The described invention is susceptible to modifications with regard to specific uses, but all such modifications will be obvious and will be considered to be within the concepts of the presently described embodiments. 
         [0049]      FIGS. 1 to 6  show the first embodiment of the light weight preform.  FIG. 1  is a perspective view of the preform  10 ,  FIG. 2  a side elevation view of the preform  10  and  FIG. 3  a longitudinal cross-section of the preform  10 . The preform  10  is comprised of a body  12 , a shoulder  14  and an upper portion neck  20  with threads  24  for attaching a closure when the preform is blown into a container. The preform neck  20  has a top rim  22  and an interior surface  21 . The neck finish includes the threads  24 . Below the threads  24  are a sealing ring  26  and a support ring  16 . The sealing ring can provide for a seal between the closure for the resulting container. The support ring has the purpose of supporting the preform after being formed usually by injection molding and during removal from the injection molding process and during subsequent conveying and handling while being transported to and inserted into a blow mold. In the blow mold the preform is heated and a high pressure gas is blown into the preform to stretch it to the internal shape of the mold portion of the blow mold. The preform support ring  16  is shown having void spaces  18  to reduce the weight of the support ring, but yet maintain sufficient strength in handling the preform in the blow molding of the preform to the container. 
         [0050]      FIGS. 4 to 6  show primarily the upper part of the preform  10  of  FIG. 1  in more detail. This primarily is the neck  24 .  FIG. 4  is a top plan view, which in addition to the showing the body  12 , shows the support ring  16  with void spaces  18  to thus light weight the support ring. The void spaces  18  will decrease the weight of the support rings by up to about 42%. Also shown are threads  24  and portions of seal ring  26  in spaces between the threads.  FIG. 5  is a bottom plan view which shows the body  12 , support ring  16  with void spaces  18  and the seal ring  26 .  FIG. 6  is a perspective view of the upper portion  20  of the preform  10  showing the interior surface  21 , upper edge  22 , threads  24 , the seal ring  26  and the support ring  16  with void spaces  18 . 
         [0051]      FIGS. 7 to 9  disclose a first alternate embodiment of the preform  10 . The body of the preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 7  shows a top plan view of the first alternate embodiment,  FIG. 8  a bottom plan view, and  FIG. 9  a perspective view of the upper portion  20  of the preform  10 . In these views there is shown the upper portion neck which remains part  20 , the threads  24 , the seal ring  26 , the upper edge  22  and the inner surface  21 . The support ring is  36  with upper supports  30 ,  32 ,  34 , and  38 . The support ring has a weight of up to about 55% less than a usual support ring. Also shown in this view is the upper portion  20  of body  12  and the shoulder  14  of the preform  10 . 
         [0052]      FIGS. 10 to 12  disclose a second alternate embodiment of the preform  10 . The body  12  of the preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 10  shows a top plan view of the second alternate embodiment,  FIG. 11  a bottom plan view, and  FIG. 12  a perspective view of the upper portion  20  of the preform  10  of the second alternate embodiment. In these views there is shown the neck upper portion  20 , the threads  24 , the seal ring  26 , the upper neck edge  22  and the inner surface  21  of the neck. The support ring is  46  with a plurality of lower supports  48 . Although there is shown a large number of supports  48  these can range from about four to the number shown in  FIGS. 10 to 12 . This support ring  46  has a weight of up to about 45% less than a usual support ring. Also shown in this view is the upper part of body  12  and the shoulder  14  of the preform  10 . 
         [0053]      FIGS. 13 to 15  disclose a third alternate embodiment of the preform  10 . The body of the preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 13  shows a top plan view of the third alternate embodiment,  FIG. 14  a bottom plan view, and  FIG. 15  a perspective view of the upper portion  20  of the preform  10 . In these views there is shown the neck upper portion  20 , the threads  24 , the seal ring  26 , the neck upper edge  22  and the neck inner surface  21 . The support ring  56  is comprised of two disc sections attached at given points. These are sections  56   a  and  56   b  attached at connectors  57 . The support ring  56   a / 56   b  can have a weight of up to about 43% of that of a usual support ring. Also shown in the  FIG. 15  view is the upper part of body  12  and the shoulder  14  of the third alternate embodiment of preform  10 . 
         [0054]      FIGS. 16 to 18  disclose a fourth alternate embodiment of the preform  10 . The body of the preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 16  shows a top plan view of the fourth alternate embodiment,  FIG. 17  a bottom plan view, and  FIG. 18  a perspective view of the neck upper portion  20  of the fourth alternate embodiment of preform  10 . In these views there is shown the upper portion of the preform  20 , the threads  24 , the seal ring  26 , the neck upper edge  22  and the neck inner surface  21 . The support ring  66  is comprised of a disc supported by a plurality of lower supports  64 . Although there is shown seven supports these can be fewer than seven supports and more than seven supports. This support ring structure has a weight of up to about 64% less than a usual support ring. Also shown in  FIG. 18  is the upper part of body  12  and the shoulder  14  of the fourth alternate embodiment preform  10 . 
         [0055]      FIGS. 19 to 21  disclose a fifth alternate embodiment of the preform  10 . The body of this fifth alternate embodiment of preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 19  shows a top plan view of the fifth alternate embodiment,  FIG. 20  a bottom plan view, and  FIG. 21  a perspective view of the upper portion  20  of the fifth alternate embodiment of preform  10 . In these views there is shown the upper portion which remains part  20 , the threads  24 , the seal ring  26 , the neck upper edge  22  and the neck inner surface  21 . The support ring is  76  with a plurality of reinforcing letters  78  on a lower surface. The reinforcing letters  78  are molded into the support ring  76  at the time of forming the preform. The letters also can be embossed into the support ring. In addition the letters can be on the upper surface of the support ring  76 . The lettering can be a brand name or some form of advertising. The support ring  76  has a weight of up to about 11% less than a usual support ring. Also shown in  FIG. 21  is the upper part of body  12  and the shoulder  14  of the fifth alternate embodiment of preform  10 . 
         [0056]      FIGS. 22 to 24  disclose a sixth alternate embodiment of the preform  10 . The body of the sixth alternate embodiment of preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 22  shows a top plan view of the sixth alternate embodiment,  FIG. 23  a bottom plan view, and  FIG. 24  a perspective view of the upper portion  20  of the sixth alternate embodiment of preform  10 . In these views there is shown the neck upper portion  20 , the threads  24 , the seal ring  26 , the neck upper edge  22  and the neck inner surface  21 . The support ring is  86  has a plurality of circular voids  82  and elongated voids  80 . This mix of voids serves to strengthen the support ring. Although there is shown a large number of voids  80  and  82  these voids can range from about four to the number shown in  FIGS. 22 to 24  or more. The support ring has a weight reduction of up to about 42% less than a usual support ring. This is related to the weight reduction of the embodiment of  FIGS. 1 to 6 . Also shown in  FIG. 24  is the upper part of body  12  and the shoulder  14  of the preform  10 . 
         [0057]      FIGS. 25 to 27  disclose a seventh alternate embodiment of the preform  10 . The body of this seventh alternate embodiment of preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 25  shows a top plan view of the seventh alternate embodiment,  FIG. 26  a bottom plan view, and  FIG. 27  a perspective view of the neck upper portion  20  of the seventh alternate embodiment of preform  10 . In these views there is shown the upper portion which remains part  20 , the threads  24 , the seal ring  26 , the neck upper edge  22  and the neck inner surface  21 . The support ring  96  has a plurality of narrow width portions  97 . The varied width provides for the integrity of the support ring  96  to functionally support the perform  10  during subsequent processing to blow mold a container. Although there are shown five wide portions and five portions  97  of decreased width, these portions can range from about three wide and decreased width portions up to ten or more of each. Also there need not be the same number of wide and decreased width portions. As the number of wide and decreased width portions increase the support ring  96  will approach a circle. The support ring  96  has a weight of about 36% less than a usual support ring. Also shown in  FIG. 27  is the upper part of body  12  and the shoulder  14  of the preform  10 . 
         [0058]      FIGS. 28 to 30  disclose an eighth alternate embodiment of the preform  10 . The body of this eighth alternate embodiment of preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 28  shows a top plan view of the eight alternate embodiment,  FIG. 29  a bottom plan view, and  FIG. 30  a perspective view of the upper portion  20  of the eight alternate embodiment of preform  10 . In these views there is shown the upper portion which remains part  20 , the threads  24 , the seal ring  26 , the neck upper edge  22  and the neck inner surface  21 . The support ring is  116  has an L-shape as shown in a partial cross-section in  FIG. 30A . The L-shape has a top surface of  117  and a side surface of  118 . The support ring  116  has a weight of up to about 36% less than a usual support ring. Also shown in  FIG. 29  is the upper part of body  12  and the shoulder  14  of the fifth alternate embodiment of preform  10 . 
         [0059]      FIGS. 31 to 33  disclose a ninth alternate embodiment of the preform  10 . The body of the ninth alternate embodiment of preform  10  is the same as in  FIGS. 1 to 3 .  FIG. 31  shows a top plan view of the ninth alternate embodiment,  FIG. 32  a bottom plan view, and  FIG. 33  a perspective view of the upper portion  20  of the ninth alternate embodiment of preform  10 . In these views there is shown the neck upper portion  20 , the threads  24 , the seal ring  26 , the neck upper edge  22  and the neck inner surface  21 . The support ring is  126  has a plurality of support nodes  128 . This mix of nodes  128  serves to strengthen the support ring. Although there is shown a large number of nodes these nodes can range from about three to the number shown in  FIGS. 31 to 33  or more. The support ring has a weight reduction of up to about 25% less than a usual support ring. This is related to the weight reduction of the embodiment of  FIGS. 1 to 6 . Also shown in  FIG. 24  is the upper part of body  12  and the shoulder  14  of the preform  10 . 
         [0060]    As noted above the preforms preferably are polyester preforms. Useful polyesters include polyethylene terephthalate and polyethylene naphthanate. Other blow moldable resins also can be used but the polyester resins usually have a lower cost and blow molding equipment is readily available for processing polyester performs to containers.