The described embodiments generally relate to beverage containers that are constructed from multiple layers of material.
An example embodiment is a bottle with a neck and a base that includes an outer layer made from plastic. An inner layer is located inside the outer layer and contacts the outer layer at the neck. The inner layer is made from a plastic material that shrinks or flexes to accommodate a change in its interior volume due to, for example, a beverage cooling within the interior volume. The inner layer may separate or otherwise move away from the outer wall to accommodate the change in volume. For example, there may be a space between the outer shell and the inner layer. A gas, such as air, may occupy the space between the outer layer and the inner layer. The gas may be drawn from the atmosphere around the bottle, or may be generated between the outer layer and the inner layer by, for example, a gas-introduction system in fluid connection with the space between the outer layer and the inner layer.
The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art(s) to make and use the invention.
The present invention(s) will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings. References to “one embodiment,” “an embodiment,” “an exemplary embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
Plastic beverage containers, such as bottles, made from materials such as Polyethylene terephthalate (“PET”) are widely used in the beverage industry to package beverages. PET bottles are a low-cost and lightweight alternative to bottles made from other plastic materials and materials such as glass or aluminum. Many beverages are filled into bottles at an elevated temperature. This practice, commonly known as “hot fill,” is used to prevent contamination of beverages. This allows the beverage to be filled into a bottle without the need for additional sterilization. After the bottle is filled and capped, the beverage is allowed to cool from the elevated filling temperature. As the beverage cools it—along with correspondingly cooling air within the bottle—undergoes thermal contraction in volume.
Because the bottle is sealed while it cools, in order to accommodate this contraction of volume the walls of the bottle may deform so that the volume of the interior of the bottle reduces along with the reduction in volume of its contents.
Some bottles may be designed to resist such deformation, for example by including ribs or thick walls. However this can require substantial additional material and added cost, and may result in a significant negative pressure within the bottle. Some bottles may be designed with movable walls and panels that are designed to flex inwardly to accommodate the interior reduction in volume attendant to thermal contraction of the bottle contents. However this can require unwanted interruptions and irregular surfaces in the visual and tactile aspects of the bottle. Such surface structures can also make a bottle hard or awkward for a user to squeeze, which some users may want to do to facilitate drinking from the bottle (e.g., through a reclosable spout).
Embodiments described herein, however, accommodate a hot-filled bottle's interior reduction in volume attendant to thermal contraction of the bottle contents without resisting the change in volume. The resulting bottle does not require exterior movable walls and panels, and does not change exterior shape due to the thermal contraction of the beverage. For example, a bottle can include a multi-layer wall construction, where the plastic inner layer of the bottle wall can move independently away from the plastic outer layer of the bottle wall to accommodate a change in internal volume of the bottle. In other words, there may be a space between the outer layer and the inner layer. And although the inner layer deforms, by shrinking or flexing, and pulls away from the outer layer so that the internal volume of the bottle changes, the outer layer maintains its shape. Therefore the outer shape of the bottle remains constant throughout the thermal contraction of its contents, while the inner layer shrinks or flexes to accommodate the thermal contraction.
As shown in
Because inner layer 114 separates and moves away from outer layer 112 and shrinks, flexes, or otherwise deforms to accommodate thermal contraction of beverage 10, outer layer 112 does not appreciably deform or otherwise change shape due to the thermal contraction of beverage 10, and therefore bottle 100 maintains its original exterior appearance. All of the volume reduction within bottle 100 due to thermal contraction of beverage 10 is accommodated by inner layer 114. In an embodiment, inner layer 114 remains attached to outer layer 112 at neck 126 (e.g., via interlayer 116), even after thermal contraction of beverage 10. In some embodiments, inner layer 114 remains attached to outer layer 112 at base 122 (e.g., via interlayer 116) even after thermal contraction of beverage 10. Such attachment may help to maintain the position of inner layer 114 within outer layer 112 after inner layer 114 moves away from outer layer 112. As discussed in further detail below, in some embodiments, various techniques may be used to ensure that inner layer 114 shrinks or flexes in a controlled manner away from outer layer 112 (e.g., uniformly, or in a controlled pattern), thus keeping deformation of inner layer 114 and correspondence or difference between the shapes of inner layer 114 and outer layer 112 controlled. When bottle 100 is opened for the first time, and the interior of inner layer 114 is exposed to ambient pressure, inner layer 114 will expand in volume and move towards outer layer 112.
Such attachment may be effected by, for example, controlling the thickness of inner layer 114 and outer layer 112 as bottle 100 is formed. For example, forming inner layer 114 thicker at neck 126 and base 122 may give it increased rigidity such that inner layer 114 at neck 126 and base 122 is less apt to deform, and thus less apt to separate from outer layer 112 at those positions when undergoing thermal contraction. In this case, all thermal contraction of beverage 10 will be accommodated by portions of inner layer 114 between neck 126 and base 122. In some embodiments inner layer 114 remains attached to outer layer 112 at neck 126, and not at base 122, or at base 122 and not at neck 126, or at both neck 126 and base 122. Space 30 is the space between outer layer 112 and inner layer 114. Space 30 may be distributed evenly between outer layer 112 and inner layer 114. However, in some embodiments and circumstances, space 30 may not necessarily be distributed evenly between outer layer 112 and inner layer 114. For example, if bottle 100 is upright, space 30 may be relatively even around body 120, but if bottle 100 is on its side, space may be concentrated upward, since the weight of beverage 10 may put inner layer 114 closer to outer layer 112 on the downward side of bottle 100. Space 30 may be filled with a gas. In some embodiments, this gas may be ordinary air, which is a blend of oxygen, nitrogen, and trace gases. In other embodiments, space 30 may be filled with other gases or gas mixtures, such as nitrogen gas, argon gas, carbon dioxide gas, or any other suitable gas or gas mixture.
In a three-layer wall as shown, for example, in
Some benefits of the above-described bottle 100 are that bottle 100 can be designed with relatively thin walls that do not include any ribs or panels in outer layer 112 to resist or accommodate deformation caused by volume and/or pressure reduction within bottle 100 due to thermal contraction of beverage 10. Another benefit of these embodiments is that space 30 may provide insulating properties to beverage container 1. Heat transfer may be reduced across space 30, and thus a chilled beverage 10 in bottle 100 will reach equilibrium with the outside temperature at a slower rate. Another benefit of the above embodiments is that resulting bottle 100 is “squeezable” by a consumer, and the aesthetics and feeling of bottle 100 in the hand of a consumer during squeezing is improved when compared to those of ordinary plastic bottles that may be squeezed. This is because the same ribs, panels, and other structure that are used to inhibit or control deformation in some plastic hot-fill bottles also tend to resist deformation from squeezing, making a bottle hard and awkward for a user to squeeze, often result in in a cracking or crinkling sound and feeling during squeezing. Embodiments of bottle 100 as described here have a smooth exterior and will have minimal or no cracking and crinkling and lower resistance to squeezing.
As discussed above, delamination between two of outer layer 112, inner layer 114, and interlayer 116 occurs when inner layer 114 deforms to accommodate the contraction of cooling beverage 10 in sealed bottle 100. Controlling the delamination can be accomplished in a variety of ways. For example, in an embodiment one or more of interlayers 116 may be a release material that weakens attachment of inner layer 114 to outer layer 112, thereby promoting release, or delamination, of inner layer 114 from outer layer 112 as described above. Release material interlayer 116 may be co-injected between outer layer 112 and inner layer 114 (e.g., when the preform of bottle 100 is being created). Selective injection of the release material can be used to control the position of delamination of inner layer 114 from outer layer 112. For example, release material interlayer 116 may be confined to cylindrical body 120, which would result in delamination being concentrated in that section of bottle 100.
Alternatively or additionally, to promote delamination, two or more of outer layer 112, inner layer 114, and interlayer 116 may be formed from materials that do not form a strong bond with each other. The weakness of the bonds between such incompatible materials promotes delamination when beverage 10 cools and contracts as described above. The placement of the incompatible materials in bottle 100 can be varied to promote or inhibit delamination in various sections of bottle 100. Further the thicknesses of outer layer 112, inner layer 114 and interlayer 116 throughout the body may be varied to promote or inhibit delamination at various positions. As discussed above, thicker layers resist the inward forces caused by the pressure differential between the inside of bottle 100 and the ambient atmospheric pressure. Thus, thicker portions of the walls of bottle 100 deform less and are more resistant to delamination. Thinner portions of the layers, by contrast, may tend to delaminate easier than thicker portions. So by forming, for example, inner layer 114 thinner in cylindrical body 120 than in shoulder 124, inner layer 114 may delaminate from outer layer 112 (with or without interlayer 116) in cylindrical body 120 and not in shoulder 124 of bottle 100
Alternatively or additionally, to control delamination, inner layer 114 may include one or more vertical ribs 115 (e.g., on an inner surface of inner layer 114). As shown in
Vertical ribs 115 may help provide a way to control deformation of inner layer 114. For instance, evenly-spaced ribs around inner layer 114 may help minimize a tendency for delamination of inner layer 114 to concentrate in any one location, by inhibiting the degree of deformation that can occur between adjacent ribs 115.
Any of the techniques described here may be used alone or in combination to control delamination of the layers. For example, inner layer 114 and outer layer 112 may be made from incompatible materials that form a weak bond, and certain portions of bottle 100, for example layers 112, 114, 116 in neck 126 and base 122, may be made thick enough to resist delamination. In this way, delamination can be made to occur only in a desired section of bottle 100, for example, cylindrical body 120. As discussed above, the selective injection of the release material can also be used to control the position of delamination of inner layer 114 from outer layer 112 by effectively weakening the bond between inner layer 114 and outer layer 112 where desired.
In some embodiments, to further help maintain the outer shape of bottle 100, outer layer 112 may include a reinforcing band 113 (see, e.g.,
In some embodiments, bottle 100 may include a label 117. As shown in
In some embodiments, bottle 100 includes a gas introduction system 200 (see, e.g.,
In some embodiments, as shown, for example, in
In some embodiments, inner layer 114 is configured to cover or close venting openings 210 before bottle 100 is filled with a beverage. In these embodiments inner layer 114 may configured to break away from venting openings 210 and thus to allow air to enter space 30 through venting openings 210, thereby equalizing the pressure in space 30 with the ambient pressure. In some embodiments, venting openings 210 may be located in an area of bottle 100 that experiences significant stretch during the molding process, such that the area is relatively thinner than other areas of the bottle. For example, venting openings 210 may be located at an area of outer layer 112 where the material of outer layer 112 has a high total stretch ratio (e.g., at an area of outer layer 112 where the stretch ratio is in the top 10th percentile of the stretch ratios throughout the material of outer layer 112). Upon heating of inner layer 114 (e.g., approaching and, in some cases passing, its glass transition temperature) caused by, for example, the filling of bottle 100 with a hot beverage, the thin layer of material of inner layer 114 covering venting opening 210 may contract and then break open vent 210 (e.g., due at least in part to thermal orientation reversal of the material surrounding venting openings 210 caused by the heating of the material). This controlled breakage may be fine-tuned by selecting the thickness of outer layer 112 and inner layer 114 that surround the venting openings 210.
In some embodiments, alternatively or additionally, a pressure change within interior volume 20 can cause inner layer 114 to move inwardly away from venting openings 210 (e.g., due to a pressure change, for example due to thermal contraction, within interior volume 20) and to thereby break open venting openings 210 (e.g., when a threshold pressure differential between interior volume 20 and the atmosphere outside the bottle is reached). This pressure differential may be caused by the contraction of inner layer 114 after bottle 100 is filled with a hot beverage, or, it may be caused by an external source of vacuum applied to bottle 100 (e.g., before bottle 100 is filled).
In some embodiments, after cooling of beverage 10 is completed, venting openings 210 may be sealed or covered (e.g., by application of a label adhered around venting openings 210.
In some embodiments venting openings 210 may be disposed near the top of bottle 100 (e.g., in neck 126).
Also visible in
For example, as shown in
In some embodiments, venting holes may exit outer layer 112 closer to opening 128 (e.g., through a thread, between threads, through a tamper-evident formation, through a flange) such that they are covered by cap 130 when cap 130 is screwed onto bottle 100.
In some embodiments, as shown, for example, in
In some embodiments outer layer 112 may be configured to act as gas introduction system 200. For example, outer layer 114 may be configured to allow gas particles to enter and exit space 30 as needed. Outer layer 112 may, for example, be made from a porous material, which can be formed by adding a cavitation additive to the plastic material that outer layer 112 is formed from. In this way, the gas pressure in space 30 can equalize with the ambient gas pressure found outside of outer layer 112.
Embodiments of bottle 100 may be manufactured using several different methods. In a single preform method, the plastic material of outer layer 112, inner layer 114, and any interlayers 116 are simultaneously injected into a preform mold. After the injection of the layers, the resulting preform can be expanded into the desired bottle shape by inserting the preform into a female mold of the proper shape and blowing heated air into the preform. In a multi-stage preform method, at least outer layer 112 and inner layer 114 are manufactured using separate preform molds. Inner layer 114 is then inserted into outer layer 112. Inner layer 114 and outer layer 112 are then fixed to each other by any suitable method, including adhesives or plastic welding.
A method of controlling deformation of a beverage container during cooling of a beverage includes filling bottle 100 with a hot beverage and sealing bottle 100. As the beverage is allowed to cool, the beverage undergoes thermal contraction upon cooling. At least inner layer 114 separates from outer layer 112 such that inner layer 112 moves inward away from an outer layer 114 of the layers of bottle 100 to reduce an internal volume of bottle 100 in response to the thermal contraction of the beverage.
The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the claims and their equivalents.
This application claims the benefit of U.S. Provisional Patent Application No. 62/712,042 filed on Jul. 30, 2018, which is incorporated herein in its entirety by reference thereto.
Number | Date | Country | |
---|---|---|---|
62712042 | Jul 2018 | US |