Abstract:
Hot-fillable, blow molded, wide-mouth plastic containers having a pair of flex panels ( 11, 111, 211 ) for accommodating thermally induced volumetric and pressure variations while affording easy contents scoopability, and desirable labeling features. The containers are capable of being blow-molded from injection molded preforms or from extruded parisons. The containers may be hot-filled and retorted. A desirable base ( 27, 127, 227 ) for a retortable container is also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a 371 of PCT/US00/05118, which claims the benefit of the priority of U.S. patent application Ser. No. 60/122,317, filed Mar. 1, 1999 and U.S. patent application Ser. No. 60/142,177, filed Jul. 1, 1999. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to wide mouth blow molded plastic containers, and more particularly to such containers having opposed chordal vacuum flex panels which are particularly suited for hot-filling and/or retorting viscous products. 
     BACKGROUND OF THE INVENTION 
     A number of hot-fillable blow molded containers are disclosed having panels that flex due to the hot-filling process. For example, U.S. Patents to: Brown 5,141,120; Brown 5,141,121; Krishnakumar 5,472,105; Prevot 5,392,937; and Prevot D344,457 disclose hot-fillable bottles having panels providing the dual function of affording grippability and vacuum-accommodating flexure. U.S. Pat. No. 5,887,739, issued to Graham Packaging Company, L. P., and owned in common with the present application, discloses a blow-molded wide-mouth container having a plurality of vacuum-flex panels spaced apart about its periphery. U.S. Pat. No. D420,593, also owned by Graham, discloses a pinch-grip wide mouth container. While the patented Graham wide mouth containers afford the advantage of ready scoopability of contents, the flex panels and dome structural intrusions into the container may impede thorough scoopability for certain types of viscous food products. Unlike containers having conventional peripheral flex panels that afford wrap-around labeling, flex panel grip containers of the type disclosed in the above patents have limited labelable areas due to the presence of the unlabelable grip areas between the front and rear label panels. 
     In retort processing of containers filled with viscous products, such as sauces, the container is subjected to greater internal pressures and volumetric changes than occurs with hot-fill processing. This is due to the higher processing temperatures, and, therefore, the greater expansion of the contained products and associated vapor. In an attempt to provide a satisfactory retortable blow-molded plastic container, U.S. Pat. No. 4,642,968 discloses a cylindrical wide-mouth container having a bottom structure which bulges outwardly to accommodate internal forces developed during retorting. See also U.S. Pat. Nos. 5,217,737 and 5,234,126. U.S. Pat. No. 5,908,128 discloses a narrow-neck bottle having a plurality of peripheral flex panels that accommodate internal forces due to pasteurization. The &#39;128 patent does not provide ready contents scoopability because it has a narrow neck and is encumbered with a plurality of internal flex panel structural elements that interfere with contents scooping. 
     There is, therefore, a need for a wide mouth container having a simple flex panel that presents a minimum of structure that can interfere with scooping of contents yet which is effective in absorbing vacuum without undesirable structural problems. There is also a need for such a container that provides a maximum amount of surface area for labeling. Furthermore, there is a need for a retortable wide mouth container that can be produced by economical extrusion blow-molding technology. 
     OBJECTS OF THE INVENTION 
     With the forgoing in mind, an object of the present invention is to provide novel hot fillable plastic containers which have vacuum absorption panels that flex during hot-filling, capping and cooling; which are resistant to unwanted distortion; and which have a minimum of internal structure that could impede thorough contents scooping. 
     Another object of the present invention is to provide wide-mouth, blow-molded jars having flat flex panels that present minimal interference with out-scooping of contents by a consumer and that maximize labelable areas. 
     A further object of the invention is to provide a wide-mouth, blow-molded jar structure that can be used in either hot-fill processing or in retort processing. 
     Yet another object of the invention is to provide a wide-mouth, blow-molded retortable jar that can be produced by conventional extrusion blow-molding technology. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, features and advantages of the invention should become apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a side elevational view of one embodiment of a container according to the present invention, the opposite side elevational view being a mirror image thereof, 
     FIG. 2 is a front elevational view of the container shown in FIG. 1; 
     FIG. 3 is a rear elevational view of the container shown in FIG. 1; 
     FIG. 4 is a top plan view of the container shown in FIG. 1; 
     FIG. 5 is a bottom plan view of the container shown in FIG. 1; 
     FIG. 6 is side elevational view of another embodiment of the present invention; 
     FIG. 7 is a front elevational view of the container illustrated in FIG. 6; 
     FIG. 8 is a rear elevational view of the container illustrated in FIG. 6; 
     FIG. 9 is a transverse cross-sectional view taken on line  9 — 9  of FIG. 6; 
     FIG. 10 is a side elevational view of an extrusion blow-molded retortable container; embodying the present invention 
     FIG. 11 is a bottom plan view of the container illustrated in FIG. 10; 
     FIG. 12 is an enlarged transverse cross-sectional view taken on line  12 — 12  of FIG. 11; 
     FIG. 13 is a side elevational view of a modified embodiment of the container of FIG. 10; and 
     FIG. 14 is a rear elevational view of a further modified embodiment of the container of FIG.  10 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As illustrated in FIG. 1, the present invention provides a blow molded, hot-fillable wide mouth jar J that has a body  10  with a pair of chordal vacuum flex panels  11  with flat outer surfaces situated as shown in FIGS. 2 and 3. The flex panels  11  are connected by an arcuate front label panel  13  and an arcuate rear label panel  15  of smaller arcuate extent than the front panel  13 , so that the panels  11  are asymmetrically disposed, both converging toward the rear of the jar J depicted to the right in FIG.  1 . The flex panels  11  are planar, as manufactured, and flex in response to hot-filling, capping and cooling. Each flex panel is identical in construction to the other. 
     As illustrated in FIG. 1, the flex panel  11  is vertically elongate and is defined by two opposing upper and lower U-shaped reinforcing rib structures,  19  and  20 , respectively. Each rib structure is identical to the other and is characterized by a pair of parallel vertical legs  19   a  which are connected together by an integral peripheral brow web  19   b.    
     As illustrated in FIG. 3, the brow web  19   b  has a wall portion  19 ′ that is angulated with respect to the planar vacuum panel  11  and has a region of maximum intrusion extending centrally into the flex panel and end regions of minimum intrusion adjacent the intersections of the brow web  19   b  and the legs  19   a . The region of maximum intrusion of the brow web wall portion  19 ′ intersects the flex panel  11  at an included angle α of about 120°. 
     As depicted in FIG. 1, each brow web  19   b  has a portion, opposite the flex panel, which extends peripherally of the jar inwardly adjacent conventional peripheral label bumpers. The ends of the rib structure legs  19   a  terminate in spaced endwise relation adjacent the transverse median M of the flex panel. The brow web and legs are continuously inwardly concave throughout their entire extents. The U-shaped reinforcing rib structures  19  cooperate to prevent ovalization of the jar without interfering with the desired movement of the planar flex panels  11  in the course of providing the vacuum absorption function during hot-fill processing. The legs  19   a  provide anti-slip bights at the front and rear vertical edges of the flex panels. 
     The upper portion of the jar J has a conventional dome shape  23  which terminates in a wide mouth threaded finish  25 . When made of PET and used in hot-fill applications, the base  27  of the jar preferably has radially extending ribs (not shown) such as customarily used by Graham in connection with other of its hot-fill containers made of PET. An advantage of this jar structure is that in addition to providing the requisite vacuum absorption, it minimizes the amount-of internal structure that can impede thorough out-scooping of contents. 
     Another embodiment of the invention which provides enhanced labelability is illustrated in FIGS. 6 through 9. This embodiment is similar in most respects to the previously-described embodiment but has certain structural differences in the flex panel region that provide additional advantages. More specifically, as best seen in the transverse cross section of FIG. 9, the front label panel  113  merges smoothly and continuously into the front vertical margin of each flex panel  111  along an arcuate transition wall  130  having a relatively large radius of curvature, R c , on the order of at least about 0.5 inch. The smooth radiused transition enables a continuous label L, a portion of which is shown in phantom in FIG. 6, to be wrapped onto the front label panel  113  and into frontal vertical margins of each flex panel  111 . Desirably, a single, inwardly-concave, vertical rib  150  is provided along the intersection of the rear panel  115  and the rear of each flex panel  111 . The rib  150  provides vertical strength, and a bight that facilitates anti-slip gripping. 
     This embodiment provides the advantages of the previously-discussed embodiment, along with a larger label mounting area because the front label can be wrapped into the flex panel grip area, thereby enabling the front label to occupy one-half or more of the periphery of the jar body. If desired, the rear panel may be labelled, or logos may be molded into the rectangular framed panel regions  115   a ,  115   b ,  115   c.    
     Preferably, the planar flex panels of each disclosed embodiment taper chordally from front to rear at a dihedral angle β (FIG. 9) of from about 16° to about 32°, a 24° angle being shown in the illustrated embodiment. The chordal extent of each flex panel preferably corresponds to almost 30 percent of the transverse medial jar body circumference (ie. at least about one-half of the diameter of the container) and should be within a range of about 20 to about 40 percent. The height of each flex panel is about 50 percent greater than the chordal extent. The total labelable area of the jar illustrated in FIG. 6 is about 20 in 2 . This is about 50 percent of the total peripheral surface of the body portion of the jar. Each flex panel is preferably smooth, although each may include a mottled surface, or may be embossed with decorations or logos. The containers illustrated in FIGS. 1-9 have a volumetric capacity of 24.5 fluid ounces, and are illustrated at full scale. 
     Preferably, each container is manufactured of PET plastic from an injection-molded preform by a process such as disclosed in Graham&#39;s copending application Ser. No. 09/126,170, filed on Jul. 30, 1998, and entitled Wide Mouth Blow Molded Plastic Container, Method of Making Same, and Preform Used Therein, the disclosure of which is incorporated by reference herein. A wide-mouth container manufactured by this process is disclosed in Graham&#39;s U.S. Pat. No. 5,887,739, referenced at page 1, the disclosure of which is incorporated by reference herein. 
     The disclosed container structures can be made by stretch blow-molding from an injection molded preform of any of several well known plastic materials, such as PET, PEN, and the like. Such materials have proven particularly suitable for applications involving hot-fill processing wherein contents are charged at temperatures of greater than 190° F. before the container is capped and allowed to cool to ambient temperatures. 
     A container structure disclosed in FIGS. 10-14, which is similar to the container of FIGS. 1-5 but with certain modifications, has been found capable of withstanding the rigors of retort processing at temperatures up to 260° F. under super-baric pressure conditions. Such structure is capable of being manufactured of single or multiple layer materials by economical extrusion blow-molding processes, as well known in the art. For example, when an extruded parison having a six (6) layer wall structure of either virgin PP or HDPE, compatible regrind, adhesive, EVOH, adhesive, and virgin PP or HDPE is blow-molded into a 32 fluid ounce container structure (illustrated at approximately twice full scale in FIG. 12) the resulting extrusion blow-molded container is product-opaque; provides acceptable shelf-life for a contained viscous product, such as sauce; is economical to manufacture; and is retortable. The term retortable, as used herein, is intended to mean that a filled and capped container is capable of being heated to temperatures up to 260° F. at pressures up to 45 psi and cooled to ambient temperatures without undergoing distortion that would be commercially-unacceptable to the ultimate consumer. 
     According to the present invention, retortability is facilitated by an improved base construction which cooperates with the pair of flex panels to prevent the base from undergoing excessive outward deflection, ie, deflection below the container standing ring. To this end, as best seen in FIG. 10, a base  227  of the illustrated cross-sectional configuration has an annular peripheral standing ring  227   a  that provides upright support for the container when placed on a flat horizontal surface S. The base  227  has an outer upwardly and radially-inwardly extending annular wall portion  227   b  that tapers at an angle of 10° from the horizontal surface S. The wall portion  227   b  merges with an inner upwardly and radially-inwardly extending wall portion  227   c  that forms an angle of 45° with respect to a horizontal plane parallel to the horizontal plane of the support surface S. The outer and inner wall portions  227   b  and  227   c  are connected by an inwardly concave wall portion having a radius of curvature R 1 . The inner wall portion  227   c  merges with an inwardly convex wall portion  227   d  having a radius of curvature R 2  which is larger than radius R 1 . The convex wall portion  227   d  slants downwardly toward a central circular wall portion  227   e  coaxial with the container central axis. The central circular wall portion  227   e  is located at an elevation H 1  lower than the elevation H 2  of the apogee  227   f  of the inner tapered wall portion  227   c . As seen in FIG. 11, the base  227  has a transverse mold-parting seam  227   e  which is characteristic of an extrusion blow-molded parison. 
     Simulated retort tests were conducted on a jar of the configuration illustrated in FIGS. 10-12, which is like the jar of FIGS. 1-6, but which has continuous peripheral outwardly concave reinforcing rings  230  and  231 , respectively located above and below the upper and lower brows  219  and  220 , respectively. The jar was extrusion blow-molded of a polypropylene multi-layer wall composition noted, supra, and had the base configuration of FIG.  12  and dimensions set forth in Column A in Table I. The jar was hot-filled with water at a temperatures of 150° F.; was provided with a 10 percent headspace; and was capped. To the capped jar, 1.7 fluid ounces of hot water at 150° F. was added under pressure to simulate internal. pressures experienced during retorting. 
     During the test, it was observed that the flex panels flexed outwardly while the base  227  acted like a diaphragm and deflected downwardly with its central wall portion  227   f  remaining above the level of the standing ring surface S. It is estimated that the flex panels accommodated about 50 percent of the combined flex panel and base accomodated volumetric expansion of the jar under simulated retort conditions. The combined volumetric expansion was about 80% of the total jar volumetric expansion. The coaction of the base  227  with the pair of flex panels  211  that flexed in preference to the base, and the other disclosed structural features, enabled the jar to be retortable. 
     By way of example, and not by way of limitation, two 32 fluid ounce capacity wide-mouth jars (A and B), both of the sidewall configuration illustrated in FIG. 13, having an overall height of 7 inches, a flex panel length of 3.5 inches and width of 2.0 inches, a maximum outside body diameter of 3.7 inches, and base configurations with the dimensional relations (in inches) in Table I were tested satisfactorily under the simulated retort conditions noted above. Sample B had an outer annular wall angle of 17° instead of 10° as in Sample A. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                 Parameter 
                 A 
                 B 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 D 1   
                 3.25 
                 3.25 
               
               
                 D 2   
                 2.38 
                 2.38 
               
               
                 D 3   
                 1.73 
                 1.73 
               
               
                 D 4   
                 0.39 
                 0.39 
               
               
                 H 1   
                 0.13 
                 .195 
               
               
                 H 2   
                 0.25 
                 .315 
               
               
                 R 1   
                 5.94 
                 7.75 
               
               
                 R 2   
                 6.35 
                 6.35 
               
               
                   
               
             
          
         
       
     
     While these dimensional relations functioned well for a 32 ounce jar, when scaling-up for larger capacity retortable jars, D 3  should be made as large as possible, and H 1  should be larger. 
     If desired, the extrusion blow-molded retortable jar shown in FIG. 10 may have a flex panel frame structure such as shown in FIG.  13 . With such frame structure, the upper and lower U-shaped reinforcing ribs  319  and  320  have shorter legs  319   a ,  320   a  separated from aligned vertically elongate ribs  319 ′. 
     Alternatively, instead of the series of vertically-spaced separately framed panels illustrated at the rear of the retortable jar embodiment illustrated in FIGS. 6-8, a jar may be provided with a single vertically-elongate arcuate rear panel  415 , as shown in FIG.  14 . The rear panel  415  is particularly suited for extrusion blow-molded retortable jars. The rear arcuate panel  415  can be molded with decorative artwork and logos. 
     In view of the foregoing it should be apparent that the various embodiments of the present invention overcome the limitations of known prior art containers and achieve the objectives set forth. 
     While several preferred embodiments have been described in detail, various modifications, alterations and changes may be made without departing from the spirit and scope of the invention as defined in the appended claims.