Pinch grip for hot-fillable container

Abstract

The present disclosure provides a one-piece plastic container having a body defining a generally rectangular horizontal cross section. The container includes a first pair of opposing sidewalls and a second pair of opposing sidewalls. The body includes an upper portion, a sidewall portion and a base. The sidewall portion is integrally formed with and extends from the upper portion to the base. The base closes off an end of the container. The sidewall portion defines a grip portion having a pair of first walls that converge with a pair of second walls. The pair of first walls extend inboard from the first pair of opposing sidewalls. The pair of second walls extend inboard from the second pair of opposing sidewalls.

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 an integrally formed pinch grip portion.

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:

$\%\mathrm{Crystallinity}=\left(\frac{\rho -{\rho }_a}{{\rho }_c-{\rho }_a}\right)\times 100$

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'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. The container includes a first pair of opposing sidewalls and a second pair of opposing sidewalls. The body includes an upper portion, a sidewall portion and a base. The sidewall portion is integrally formed with and extends from the upper portion to the base. The base closes off an end of the container. The sidewall portion defines a grip portion having a pair of first walls that converge with a pair of second walls. The pair of first walls extend inboard from the first pair of opposing sidewalls. The pair of second walls extend inboard from the second pair of opposing sidewalls.

According to other features, the grip portion is further defined by two pairs of third walls. Each third wall converges with one wall of the pair of first walls and one wall of the pair of second walls. In one example, each of the pair of third walls defines an angle substantially between 15 and 35 degrees relative to the base. The pair of first walls converge with the pair of second walls at an angle substantially between 115 and 120 degrees.

According to still other features, the pair of first walls define an acute angle of convergence and the pair of second walls define an obtuse angle of convergence. In one example, the pair of first walls define an angle of convergence of about 16 degrees and the pair of second walls define an angle of convergence of about 110 degrees. Both the first and second pair of third walls define an angle of convergence of about 130 degrees.

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 elevational view a one-piece plastic container constructed in accordance with the teachings of the present disclosure;

FIG. 2 is a side elevational view of the container of FIG. 1;

FIG. 3 is a rear elevational view of the container of FIG. 1;

FIG. 4 is a bottom elevational view of the container of FIG. 1;

FIG. 5 is a sectional view of the container taken along line 5-5 of FIG. 2;

FIG. 6 is a sectional view of the container taken along line 6-6 of FIG. 2; 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. 1, the container 10 has an overall height A of about 288.18 mm (11.35 inches). As best shown in FIG. 4, the container 10 is substantially rectangular in cross sectional shape including a first pair of opposing sidewalls 12 each having a width B, and a second pair of opposing sidewalls 14 each having a width C. In the example shown, the first pair of opposing sidewalls 12 are shorter than the second pair of opposing sidewalls 14. First pair of opposing sidewalls 12 may be oriented at approximately 90 degree angles to the second pair of opposing sidewalls 14 so as to form the generally rectangular cross section as shown in FIG. 4. The width B is about 126.29 mm (4.97 inches). The width C is about 155.88 mm (6.26 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 128 fl. oz. (3785 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 shoulder region 22 merges into and provides a transition between the finish 20 and a sidewall portion 24. The sidewall portion 24 extends downward from the shoulder region 22 to a base portion 26 having a base 28. The sidewall portion 24 defines a grip portion 30. The construction of the grip portion 30 of the container 10 allows the sidewall portion 24 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.

Grip portion 30 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 sidewall portion 24 and grip portion 30 of the container 10.

With particular reference now to FIGS. 2, 5 and 6, the grip portion 30 will now be described in greater detail. In general, the grip portion 30 is defined by a pair of first walls 60, a pair of second walls 62 and two pair of third walls 64 and 66, respectively. The pair of first walls 60 extend inboard from the first pair of opposing sidewalls 12. In one example, the first walls 60 may define a pair of longitudinally extending raised ribs 70. The pair of second walls 62 extend inboard from the second pair of opposing sidewalls 14. As best shown in FIGS. 2 and 5, the first and second walls 60 and 62 may converge at an interface wall 72 substantially parallel to a longitudinal axis 76 of the plastic container 10. The pair of first walls 60 define interface walls 80 and 82 at a transition to the third walls 64 and 66 (FIG. 2). Similarly, the pair of second walls 62 define interface walls 84 and 86 at a transition to the third walls 64 and 66. One pair of third walls 64 extends from the second pair of opposing sidewalls 14 to the interface wall 80 and 84 of each of the pairs of first and second walls 60 and 62, respectively. The other pair of third walls 66 extends from the second pair of opposing sidewalls 14 to the interface wall 82 and 86 of each of the pairs of first and second walls 60 and 62, respectively. It is appreciated that the interface walls 72, 80, 82, 84 and 86, and other surfaces of the grip portion 30 may present a smooth transition to respective adjacent surfaces. Explained further, the interface walls 72, 80, 82, 84 and 86, and other surfaces of the grip portion 30 may define radiused transitions formed on the container 10 to enhance user comfort and durability of the grip portion 30 and the container 10 as a whole.

Turning now to FIG. 5, a horizontal cross section through the grip portion 30 is shown. An extension line 60′ projected from the first walls 60 defines an angle α₁ relative to a line 14′ parallel to the second pair of opposing sidewalls 14. In one example, α₁ may be between 6 and 20 degrees. An extension line 62′ projected from the second walls 62 defines an angle α₂ relative to the second pair of opposing sidewalls 14. In one example, α₂ may be between about 25 and 45 degrees. The inventors have shown through testing that one preferred configuration includes an angle α₁ of about 8 degrees and an angle α₂ of about 35 degrees. As a result, it can be shown that the first walls 60 may define an angle of convergence α₃ of about 16 degrees. Similarly, it can be shown that the second walls 62 may define an angle of convergence α₄ of about 110 degrees. Further, it can be shown that the first walls 60 converge with the second walls 62 at an angle α₅ between about 115 and 120 degrees, and more preferably about 117 degrees.

The grip portion 30 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 pair of opposing sidewalls 12 at the grip portion 30 such that a thumb engages a detent 88 formed on one of the first walls 60 and the remaining fingers engage another detent 88 formed on the other of the first walls 60. Because the first walls 60 have been slanted inboard at the angle α₁, a consumer is offered improved leverage during gripping for better control of the container 10. In one example, a span S₁ defined at the innermost location of the first walls 60 is about 72.28 mm (2.85 inches). A span S₂ defined between the innermost raised ribs 70 of the first walls 60 is about 80.59 mm (3.17 inches). A span S₃ defined at the outermost location of the first walls 60 is about 83.13 mm (3.27 inches). A depth D₁ defined at the grip portion 30 from the first pair of opposing sidewalls 12 to the interface wall 72 is about 53.34 mm (2.10 inches). A depth D₂ defined at the grip portion 30 from the first pair of opposing sidewalls 12 to land 48 is about 76.20 mm (3.0 inches). It is appreciated that the cross-sectional illustration of FIG. 5 may not be drawn to scale.

With particular reference now to FIG. 6, a vertical cross section through the grip portion 30 is shown. An extension line 64′ and 66′ projected from the third walls 64 and 66 defines an angle α₆ relative to a line 28′ parallel to the base 28. In one example, α₆ may be between about 15 and 35 degrees. The inventors have shown through testing the one preferred configuration includes an angle α₆ of about 25 degrees. It can be shown that the first pair of third walls 64 may define an angle of convergence of α₇ of about 130 degrees. Likewise, the second pair of third walls 66 may also define an angle of convergence α₇ of about 130 degrees. It is appreciated that the cross-sectional illustration of FIG. 6 may not be drawn to scale.

The resultant geometrical configuration of the respective first, second, and third walls 60, 62, 64 and 66 of the grip portion 30 provides improved localized strength at the grip portion 30 as well as creates a geometrically rigid structure. The resulting localized strength increases the resistance to creasing, buckling, denting, bowing and sagging of 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 it is able to withstand the additional pressures associated with faster filling speeds. Through testing, it has been shown that a container formed by current commercially available processes may be filled at a fill speed of 90 bottles per minute (bpm). In contrast, the container 10 may be filled at a fill speed of 110 bpm. As is shown, about an 18% improvement in fill rate is realized with the container 10 having the grip portion 30 versus current commercially available containers.

Additionally, this resultant localized strength prevents the grip portion 30 from popping out or deforming when the container is dropped during packaging and shipping. Through testing, it has been shown that a container formed by current commercially available processes can withstand a drop test up to 2.3 feet before the grip portion experiences deformation or pop out. In contrast, the container 10 having grip portion 30 can withstand a drop test up to 2.9 feet before the grip portion experiences pop out. As is shown, about a 20% improvement is realized with the container 10 having the grip portion 30 versus current commercially available containers.

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. According to one example, the grip forming region 94 may include treatment surfaces 96. Treatment surfaces 96 may be prepared to facilitate removal of the end container from the mold cavity 90 at the grip forming region 94. Exemplary treatments for the treatment surfaces 96 may include etching, sand blasting or other processes suitable to encourage separation of the end container from the mold cavity 90. The treatment surfaces 96 cause the grip portion 30 of the resultant container to have a frosted appearance.

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 177° 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 the central longitudinal axis 76 of the 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, polyethylene naphthalate (PEN), a PET/PEN blend or copolymer, and various multilayer structures may be suitable for the manufacture of plastic 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.

Claims

1. A one-piece plastic container comprising:

a body defining a generally rectangular horizontal cross section including a first pair of opposing sidewalls and a second pair of opposing sidewalls, said body having an upper portion, a sidewall portion and a base, said sidewall portion integrally formed with and extending from said upper portion to said base, said base closing off an end of said container, said sidewall portion defining a grip portion having a pair of first walls that converge with a pair of second walls, said pair of first walls extending inboard from said first pair of opposing sidewalls, respectively and said pair of second walls extending inboard from said second pair of opposing sidewalls, respectively.

2. The one-piece plastic container of claim 1 wherein said grip portion is further defined by two pairs of third walls, wherein each third wall converges with one wall of said pair of first walls and one wall of said pair of second walls, respectively.

3. The one-piece plastic container of claim 2 wherein each of said pair of third walls defines an angle substantially between 15 and 35 degrees relative to said base.

4. The one-piece plastic container of claim 3 wherein each of said pair of third walls defines an angle substantially equal to 25 degrees relative to said base.

5. The one-piece plastic container of claim 1 wherein said pair of first walls converge with said pair of second walls at an angle substantially between 115 and 120 degrees.

6. The one-piece plastic container of claim 5 wherein said pair of first walls converge with said pair of second walls at an angle substantially equal to 117 degrees.

7. The one-piece plastic container of claim 5 wherein said pair of first walls define an angle of convergence of about 16 degrees.

8. The one-piece plastic container of claim 5 wherein said pair of second walls define an angle of convergence of about 110 degrees.

9. The one-piece plastic container of claim 5 wherein said first pair of opposing sidewalls are shorter than said second pair of opposing sidewalls.

10. A grip portion of a one-piece plastic container having a generally rectangular horizontal cross section including a first pair of opposing sidewalls and a second pair of opposing sidewalls, said grip portion comprising:

a pair of first walls that converge with a pair of second walls, said pair of first walls extending inboard from said first pair of opposing sidewalls, respectively and said pair of second walls extending inboard from said second pair of opposing sidewalls, respectively, said pair of first walls defining an acute angle of convergence and said pair of second walls defining an obtuse angle of convergence.

11. The grip portion of claim 10 wherein said pair of first walls define an angle of convergence of about 16 degrees.

12. The grip portion of claim 10 wherein said pair of second walls define an angle of convergence of about 110 degrees.

13. The grip portion of claim 10 wherein said grip portion is further defined by two pairs of third walls wherein both the first pair and the second pair of third walls define an angle of convergence of about 130 degrees.

14. A grip portion of a one-piece plastic container having a generally rectangular horizontal cross section including a first pair of opposing sidewalls and a second pair of opposing sidewalls, and a base, said grip portion comprising:

a pair of first walls that converge with a pair of second walls, said pair of first walls extending inboard from said first pair of opposing sidewalls and said pair of second walls extending inboard from said second pair of opposing sidewalls, and two pair of third walls, each third wall formed on one of said second pair of opposing sidewalls and extending to both of said first and second walls, said first, second and third walls collectively configured at relative geometrical relationships to provide structural strength in said grip portion and the container as a whole.

15. The grip portion of claim 14 wherein one pair of said third walls extends to an interface wall formed with each of said pairs of first and second walls.

16. The grip portion of claim 15 wherein the other pair of said third walls extends to an interface wall formed with each of said pairs of first and second walls.

17. The grip portion of claim 16 wherein said pair of first walls extend inboard from said first pair of opposing sidewalls at a first angle less than 20 degrees relative to said second pair of opposing sidewalls, respectively.

18. The grip portion of claim 17 wherein said pair of second walls extend inboard from said second pair of opposing sidewalls at a second angle between 25 and 45 degrees relative to said first pair of opposing sidewalls, respectively.

19. The grip portion of claim 18 wherein said two pair of third walls all define a third angle between 15 and 35 degrees relative to said base.

20. The grip portion of claim 19 wherein said first angle is substantially 8 degrees, said second angle is substantially 35 degrees, and said third angle is substantially 25 degrees.