High-Clarity, Cast Polypropylene Produce Pouch and Method
A high-clarity, cast polypropylene produce pouch with first and second sidewalls and a bottom panel joined to form a pouch wherein the first and second sidewalls and the bottom panel are formed from cast polypropylene. The bottom panel can be a bottom gusset panel. The first and second sidewalls and the bottom gusset panel can have edges joined by side welding or heat sealing. Zipper or slide closures can close the first and second sidewalls. A method for forming a high-clarity, cast polypropylene produce pouch comprises creating a polypropylene (PP) resin, passing the polypropylene (PP) resin through a cast extruding machine and extruding molten polypropylene (PP) to produced extruded polypropylene (PP), rolling the extruded polypropylene (PP) in a cooling roller, and applying a surface-modifying corona treatment to the extruded polypropylene (PP).
The present invention relates generally to flexible containers. More particularly, disclosed herein is a flexible, self-standing produce pouch of high-clarity, cast polypropylene film for containing loose produce, particularly fruits and vegetables.
BACKGROUND OF THE INVENTIONPrior art bags or pouches for fruits, vegetables, and other produce are often crafted from an extruded tube of thermoplastic film. The thermoplastic film is assembled by heat sealing and processed to yield a finished pouch. Processing steps commonly include hole punching, perforating, and potentially further manufacturing steps designed to produce a specified pouch. Pouches are commonly crafted with rectangular or tapered shapes. Some pouches have zipper or slide closures with engaging male and female strips that can be selectively engaged to seal the mouth of the pouch. Other pouches are designed for being tied or fastened in a closed configuration. Pouches can incorporate handles and can be vented to help preserve freshness and to permit rinsing.
Produce pouches are commonly formed from coextruded and blown high and low density polyethylene, polyester, or polypropylene film, which may be laminated. The manufacturing process typically includes the step of sealing a bag by applying enough heat to the surface of the bag to melt the material and cause it to adhere to itself.
To heat seal bags manufactured from coextruded polyethylene, the packaging industry developed a heat sealing mechanism under which a filament generates sufficient heat to reach the melting point of the material. The inside layer of material must melt while the outer layers must be cooled so that they do not melt and cause the bag to lose its shape. Cooling can be achieved by, for example, blasts of cold air following the application of heat.
To avoid the manufacturing problems associated with heat sealing coextruded polyethylene, the packaging industry has used laminated film. Laminated film consists of layers of different material that are brought together. The layers may consist of such materials as polyethylene, polyester, paper, foil and polypropylene. The outside layer of laminated film can be a heat resistant material, such as polyester, or can be coated for heat resistance. The use of laminated film and high temperature jaws for heat sealing streamlines the manufacturing process. However, the laminated film is approximately three times the cost of coextruded polyethylene.
The prior art has also recognized that it is desirable to have produce bags or pouches that are capable of standing up when filled. Self-standing bags are desirable for a number of reasons. For example, a principal display panel can then be caused to face consumers. Further, arranging the bags in a standing position takes less space, can prevent damage and loss to the contained goods, and can be more attractive to consumers.
It is further known that retail produce merchandisers now seek high-clarity packaging for many commodities, including grapes, cherries, and other loose fruit and vegetable products. High-clarity pouches give a consumer a greater ability to view the contained goods and can increase the perceived cleanliness and quality of the fruit, vegetable, or other produce contained by the pouch. However, although desirable, high-clarity packaging can entail increased production costs. Of course, produce growers and shippers desire cost-effective packaging. Moreover, existing high-clarity constructions often do not tolerate changes in temperature well and suffer losses in clarity, strength, and durability, all quite undesirable to produce growers, shippers, sellers, and consumers.
Accordingly, it will be recognized that a high-clarity packaging solution that is innovative in construction while remaining efficient in cost and demonstrating an ability to tolerate temperature variations with limited or no loss in performance would represent a useful advance in the art of produce packaging.
SUMMARY OF THE INVENTIONWith a knowledge of the present state of the art, the present inventors set forth with the basic object of providing a pouch for produce and other goods that provides a high-clarity packaging solution.
A further object of embodiments of the invention is to provide a produce pouch with high-clarity characteristics that better tolerates temperature variations.
An additional object of the invention is to provide a produce pouch that can be manufactured and sold with cost efficiency.
Still another object of embodiments of the invention is to provide a high-clarity produce pouch that is capable of being self-standing when retaining goods.
These and further objects and advantages of the present invention will become obvious not only to one who reviews the present specification and drawings but also to those who have an opportunity to experience an embodiment of the high-clarity, cast produce pouch disclosed herein in operation. However, it will be appreciated that, although the accomplishment of each of the foregoing objects in a single embodiment of the invention may be possible and indeed preferred, not all embodiments will seek or need to accomplish each and every potential advantage and function. Nonetheless, all such embodiments should be considered within the scope of the present invention.
One will appreciate that the foregoing discussion broadly outlines the more important goals and features of the invention to enable a better understanding of the detailed description that follows and to instill a better appreciation of the inventors' contribution to the art. Before any particular embodiment or aspect thereof is explained in detail, it must be made clear that the following details of construction and illustrations of inventive concepts are mere examples of the many possible manifestations of the invention.
In the accompanying drawing figures:
The various notes, dimensions, and details on the drawings are incorporated herein by reference but should not be interpreted as limiting the invention in any manner.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTSThe produce pouch disclosed herein is subject to a wide variety of embodiments. However, to ensure that one skilled in the art will be able to understand and, in appropriate cases, practice the present invention, certain preferred embodiments of the broader invention revealed herein are described below and shown in the accompanying drawing figures.
Turning more particularly to the drawings, a produce pouch according to the present invention is indicated generally at 10 in
As best seen perhaps in
When the produce pouch 10 is in an open configuration as depicted in
The produce pouch 10 has a mouth defined by the upper edges of the first and second sidewalls 12 and 14. The mouth can be selectively closed by use of a zipper closure 18. As seen, for example, in
To permit air and liquid flow within and through the open inner volume defined by the first and second sidewalls 12 and 14 and the bottom gusset panel 16, a plurality of vents 30 can be spaced over the sidewalk 12 and 14 and the bottom gusset panel 16. In this example, the vents 30 comprise round through-holes, but it will be recognized that other shapes would be readily possible. In the depicted embodiment, however, vents 30 are not disposed over predetermined portions of the first and second sidewalk 12 and 14 such as upper and central segments thereof, to permit the application and display of display material 32.
Of course, the locations and content of the display material 32 can vary irnfinitely and can include, for instance, branding, product information, and pricing codes. Display material 32 can be centrally disposed on one or both sidewalk 12 and 14, on the bottom gusset panel 16, and potentially above the closure mechanism.
Still further, a handle 24 can be cut through each of the first and second sidewalk 12 and 14 in aligned locations, such as adjacent to the upper edges thereof In this example, the handle 24 is disposed below the zipper closure 18, but it could be disposed above the zipper closure 18 as shown and described hereinbelow. As seen in
With further reference to
The first and second sidewalk 12 and 14 and the bottom gusset panel 16 are preferably formed as cast polypropylene (PP), which has been found by the present inventors toy provide a plurality of improved performance characteristics carrying forth the goals of the invention. By way of example and not limitation, cast polypropylene permits the sidewalk 12 and 14, the bottom gusset panel 16, and the produce pouch 10 in general to exhibit high clarity, good durability, and desired improvements in performance despite fluctuations in temperature. Moreover, the cast polypropylene sidewalls 12 and 14 and bottom gusset panel 16 exhibit high resistance to chemical caustics and solutes and are reusable as necessary.
An alternative produce pouch 10 pursuant to the invention disclosed herein is depicted in
As shown in
When the produce pouch 10 is in an open configuration as depicted in
As in the embodiment of
A plurality of vents 30 are again spaced over the sidewalls 12 and 14 and, the bottom gusset panel 16 to permit air and liquid flow within and through the open inner volume defined by the first and second sidewalls 12 and 14 and the bottom gusset panel 16. As before, the vents 30 comprise round through-holes. Vents 30 are not disposed over predetermined portions of the first and second sidewalls 12 and 14, such as upper and central segments thereof, to permit the application and display of display material 32.
Again looking to
While the produce pouch illustrated in
Further embodiments of the produce pouch 10 are contemplated as in
As noted previously, the first and second sidewalls 12 and 14 and the bottom gusset panel 16 are preferably formed as cast polypropylene (PP). As contemplated hereunder, the production process can proceed as shown schematically in
The resin blend so formed can be passed through a cast extruding machine prior to undergoing molten plastic extrusion in an extruding step in the cast extruding machine and/or in a secondary extruding machine. The resulting product can then pass through a primary cooling roller, potentially followed by a secondary cooling roller. Gauge control can be undertaken to measure and confirm thickness and other parameters of the cooled and rolled product. A surface-modifying corona treatment can then be applied to the material, such as by use of a low temperature corona discharge plasma, to achieve desired surface energy characteristics of the polypropylene (PP) material. The resulting product can then be trimmed, wound, slit, and packed with the for sidewalls 12 and 14 and the bottom gusset panel 16 joined, such as by heat sealing, side welding, or any other effective practice. A 72-hour curing time can be provided prior to slitting. Printing can be applied as appropriate and may be done with high temperature ink where necessary. It will be understood that the processing time for the material will depend on, among other things, machine capacity. In one practice of the invention, for example, the full processing capacity is 22,000 pounds per 24 hour period.
With certain details and embodiments of the present invention for high-clarity, cast produce pouch 10 disclosed, it will be appreciated by one skilled in the art that numerous changes and additions could be made thereto without deviating from the spirit or scope of the invention. This is particularly true when one bears in mind that the presently preferred embodiments merely exemplify the broader invention revealed herein. Accordingly, it will be clear that those with certain major features of the invention in mind could craft embodiments that incorporate those major features while not incorporating all of the features included in the preferred embodiments.
Therefore, the following claims are intended to define the scope of protection to be afforded to the inventor. Those claims shall be deemed to include equivalent constructions insofar as they do not depart from the spirit and scope of the invention. It must be further noted that a plurality of the following claims may express certain elements as means for performing a specific function, at times without the recital of structure or material. As the law demands, these claims shall be construed to cover not only the corresponding structure and material expressly described in this specification but also all equivalents thereof that might be now known or hereafter discovered.
Claims
1. A high-clarity, cast polypropylene (PP) produce pouch comprising:
- a pouch with first and second sidewalls wherein the first and second sidewalls have edges that joined to form a pouch;
- wherein the first and second sidewalls are formed from cast polypropylene (PP) film.
2. The high-clarity, cast polypropylene (PP) produce pouch of claim 1 further comprising a bottom gusset panel joined to the first and second sidewalls.
3. The high-clarity, cast polypropylene (PP) produce pouch of claim 2 wherein the first and second sidewalls and the bottom gusset panel have edges that are joined by side welding.
4. The high-clarity, cast polypropylene (PP) produce pouch of claim 2 wherein the first and second sidewalls and the bottom gusset panel have edges that are joined by heat sealing.
5. The high-clarity, cast polypropylene (PP) produce pouch of claim 1 wherein the produce pouch has a mouth defined by edges of the first and second sidewalls and further comprising a closure mechanism for selectively joining the first and second sidewalls to close the mouth.
6. The high-clarity, cast polypropylene (PP) produce pouch of claim 5 wherein the closure mechanism comprises a zipper closure.
7. The high-clarity, cast polypropylene (PP) produce pouch of claim 5 wherein the closure mechanism comprises a slide closure and a slider for adjusting the slide closure between open and closed configurations.
8. (canceled)
9. The high-clarity, cast polypropylene (PP) produce pouch of claim 2 wherein each of the first and second sidewalls has a body portion with a rectangular upper section and a tapered lower section and wherein the bottom gusset panel has a rectangular main section and pointed ends that taper at angles corresponding to the tapered lower sections of the first and second sidewalls whereby, when the produce pouch is in an open configuration, the bottom gusset panel establishes a foot for enabling the produce pouch to be disposed in a free-standing position.
10. The high-clarity, cast polypropylene (PP) produce pouch of claim 1 further comprising a plurality of through-holes in each of the first and second sidewalls.
11. The high-clarity, cast polypropylene (PP) produce pouch of claim 2 further comprising a handle formed by handle portions disposed through the first and second sidewalls.
12. The high-clarity, cast polypropylene (PP) produce pouch of claim 11 wherein the produce pouch has a mouth defined by edges of the first and second sidewalls and further comprising a closure mechanism for selectively joining the first and second sidewalls to close the mouth wherein the handle is disposed proximal to the closure mechanism relative to the bottom gusset panel.
13. The high-clarity, cast polypropylene (PP) produce pouch of claim 11 wherein the produce pouch has a mouth defined by edges of the first and second sidewalls and further comprising a closure mechanism for selectively joining the first and second sidewalls to close the mouth wherein the handle is disposed distal to the closure mechanism relative to the bottom gusset panel.
14. A method for forming a high-clarity, cast polypropylene (PP) produce pouch with first and second sidewalls formed from cast polypropylene (PP) film, the method comprising the following steps:
- providing a molten polypropylene (PP) resin blend;
- passing the molten polypropylene (PP) resin blend through a cast extruding machine and extruding the molten polypropylene (PP) resin blend to produce extruded polypropylene (PP);
- rolling the extruded polypropylene (PP) in a cooling roller;
- providing a curing time;
- slitting the extruded polypropylene (PP); and
- joining portions of the extruded polypropylene (PP) to form a cast polypropylene (PP) produce pouch with first and second sidewalls.
15. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the step of passing the polypropylene (PP) resin blend through a cast extruding machine is carried out at a temperature of 225-235° C. (or 437-455° F.).
16. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 further comprising applying a surface-modifying corona treatment to the extruded polypropylene (PP).
17. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the polypropylene (PP) resin blend includes an anti-blocking agent.
18. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the polypropylene (PP) resin blend includes a slipping agent
19. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the polypropylene (PP) resin blend includes an antistatic agent.
20. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the polypropylene (PP) resin blend includes a nucleating agent.
21. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 therein the polypropylene (PP) resin blend includes a propylene carrier elastomer.
22. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 further comprising the step of rolling the extruded polypropylene (PP) in a secondary cooling roller.
23. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the step of joining portions of the extruded polypropylene (PP) to form a cast polypropylene (PP) produce pouch with first and second sidewalls comprises heat sealing the portions of extruded polypropylene (PP).
24. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the step of joining portions of the extruded polypropylene (PP) to form a cast polypropylene (PP) produce pouch with first and second sidewalls comprises side welding the portions of extruded polypropylene (PP).
25. The method for forming a high-clarity, cast polypropylene (PP) produce pouch of claim 14 wherein the step of providing a curing time comprises providing an approximately 72-hour curing time.
Type: Application
Filed: Jan 29, 2014
Publication Date: Jul 31, 2014
Inventors: Duke X. W. Yu (Mississauga), Philip Beach (Southbury, CT)
Application Number: 14/167,994
International Classification: B65D 75/00 (20060101); B65D 33/25 (20060101); B65D 33/08 (20060101); B65D 33/00 (20060101);