Patent Application
20110217494
This disclosure generally relates to containers for retaining a commodity, such as a solid or liquid commodity. More specifically, this disclosure relates to a blown polyethylene terephthalate (PET) container having a flexible standing ring circumferentially surrounding its base for improved container performance and reduced container weight.
This section provides background information related to the present disclosure which is not necessarily prior art.
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:
where ρ is the density of the PET material; ρa is the density of pure amorphous PET material (1.333 g/cc); and ρc 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%.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
According to the principles of the present disclosure, a blow-molded plastic container is provided having a base portion having a flexible standing ring radially extending therefrom. The flexible standing ring is disposed about a lowest most portion of the container and operable to support the container on a surface. The flexible standing ring defines an annular groove thereabout that collapses in response to internal vacuum forces and/or external loading forces. The container further comprises a body portion that extends from an upper portion to the base, such that the upper portion, the body portion and the base cooperate to define a receptacle chamber within the container into which product can be filled.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The present teachings provide for a container having a flexible standing ring that effectively absorbs the internal vacuum while maintaining its basic shape. The flexible standing ring can be described as having an integrated base fold that is flexible in the vertical direction (in a direction coaxial with a central axis A-A of the container (
As will be discussed in greater detail herein, the shape of the container of the present teachings can be formed according to any one of a number of variations. By way of non-limiting example, the container of the present disclosure can be configured to hold any one of a plurality of commodities, such as beverages, food, or other hot-fill type materials.
It should be appreciated that the size and the exact shape of the flexible standing ring are dependent on the size of the container and the required vacuum absorption. Therefore, it should be recognized that variations can exist in the presently described designs. According to some embodiments, it should also be recognized that the container can include additional vacuum absorbing features or regions, such as panels, ribs, slots, depressions, and the like.
As illustrated throughout the several figures, the present teachings provide a one-piece plastic, e.g. polyethylene terephthalate (PET), container generally indicated at 10. The container 10 comprises an integrated base fold flexible standing ring design according to the principles of the present teachings. Those of ordinary skill in the art would appreciate that the following teachings of the present disclosure are applicable to other containers, such as rectangular, 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
The exemplary container 10 may also have a neck 23. The neck 23 may have an extremely short height, that is, becoming a short extension from the finish 20, or an elongated height, extending between the finish 20 and the shoulder portion 22. The upper portion 14 can define an opening. Although the container is shown as a drinking container (
As illustrated in
Referring now to
Still referring to
With particular reference to
With particular reference to
With particular reference to
In some embodiments, foot portion 104 extends radially outwardly such that a distal portion or toe portion 108 is radially aligned with an overall shape or dimension of sidewall portion 24 and/or base portion 28 (as shown in
Flexible standing ring 100 can be characterized, in some embodiments, as an assembly having a downwardly and outwardly ring member. This arrangement results in an annular groove disposed above the ring member. The ring member further includes a lower surface that contacts the support structure, such as counter, packaging material, display shelf, and the like, and thus is located along a base portion of the container. It should be appreciated that variations of the present design of flexible standing ring 100 exist.
With particular reference to
With reference to
With reference to
With particular reference to
Turning now to
According to the foregoing, it should be appreciated that flexible standing ring 100 provides, in part, volume displacement for purposes of vacuum reduction. Specifically, as seen in
The plastic container 10 has been designed to retain a commodity. The commodity may be in any form such as a solid or semi-solid product. In one example, a commodity may be introduced into the container during a thermal process, typically a hot-fill process. For hot-fill bathing applications, bottlers generally fill the container 10 with a 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 disclosure 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 can be used that generally involves the manufacture of a preform (not shown) 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. An exemplary method of manufacturing the plastic container 10 will be described in greater detail later.
An exemplary method of forming the container 10 will be described. A preform version of container 10 includes a support ring 51, which may be used to carry or orient the preform through and at various stages of manufacture. For example, the preform may be carried by the support ring 51, the support ring 51 may be used to aid in positioning the preform in a mold cavity, or the support ring 51 may be used to carry an intermediate container once molded. At the outset, the preform may be placed into the mold cavity such that the support ring 51 is captured at an upper end of the mold cavity. In general, the mold cavity has an interior surface corresponding to a desired outer profile of the blown container. More specifically, the mold cavity according to the present teachings defines a body forming region, an optional moil forming region and an optional opening forming region. Once the resultant structure, hereinafter referred to as an intermediate container, has been formed, any moil created by the moil forming region may be severed and discarded. It should be appreciated that the use of a moil forming region and/or opening forming region are not necessarily in all forming methods.
In one example, a machine (not illustrated) places the preform heated to a temperature between approximately 190° F. to 250° F. (approximately 88° C. to 121° C.) into the mold cavity. The mold cavity 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 within the mold cavity to a length approximately that of the intermediate container thereby molecularly orienting the polyester material in an axial direction generally corresponding with the central longitudinal axis A-A of the container 10. While the stretch rod extends the preform, air having a pressure between 300 PSI to 600 PSI (2.07 MPa to 4.14 MPa) assists in extending the preform in the axial direction and in expanding the preform in a circumferential or hoop direction thereby substantially conforming the polyester material to the shape of the mold cavity 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 most of the intermediate container. The pressurized air holds the mostly biaxial molecularly oriented polyester material against the mold cavity for a period of approximately two (2) to five (5) seconds before removal of the intermediate container from the mold cavity. This process is known as heat setting and results in a heat-resistant container suitable for filling with a product at high temperatures.
Alternatively, other manufacturing methods, such as for example, extrusion blow molding, one step injection stretch blow molding and injection blow molding, using other conventional materials including, for example, high density polyethylene, polypropylene, 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.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.
