CA2109287C

CA2109287C - Thermoformed packages and methods of making same

Info

Publication number: CA2109287C
Application number: CA002109287A
Authority: CA
Inventors: H. Scott Herrin
Original assignee: Individual
Current assignee: Klearfold Inc
Priority date: 1992-10-28
Filing date: 1993-10-26
Publication date: 1994-04-29
Anticipated expiration: 2013-10-26
Also published as: CA2109287A1; US20010008240A1

Abstract

The present invention relates to thermoformed containers and processes of making thermoformed containers. The containers are cost effective, can be produced from post-consumer recycled material and, in many cases, can be classified as recyclable.

Description

~1~9 ~7 THERMOFORMED PACKAGES
AND METHODS OF MAKING SAME
The invention relates to the field of packaging technology and in particular containers produced from recycled material and methods of making same.
Two piece thermoformed blister packages have become extremely popular. Often called "clamshell packages", they generally include two or more plastic members which are held together at their periphery by mechanical structures such as ridges, by glue, by the use of a solvent, or by a heat seal. Clamshell packages may also be formed from a single sheet of material. In that situation, both the cover and container are thermoformed in the single sheet separated from one another by a fold or hinge. When the sheet is folded over onto itself, the cover and container are brought into engagement so as to form a complete package. In every case, the packaged item is thereby encased between the two sealed plastic members.
These packages are generally clear allowing the consumer to view the goods being purchased. They also afford the consumer the ability to read various advertising and instructional material therethrough.
Today, clamshell packages are used in packaging consumer electronics, compact discs, batteries and the like.
Clamshell packages are also used in packaging over-the-counter pharmaceuticals, hair care products such as combs and barrettes, and in packaging toys, just to name a few.
Retailers like these packages because they allow the consumer to see the item clearly. Retailers therefor can often eliminate providing samples or removing items from their packaging so a consumer can inspect them. Similarly, clamshell packages can often be formed with an aperture or hanging means so that the package and its contents can be suspended from a pegboard-like display. Further, clamshell packages can ~ ~ G ~
_ 2 be oversized rendering the package more difficult to steal.
However, clamshell packagers are today faced with great challenges. The cost of packaging is a source of tremendous competition such that scrutiny by product manufacturers is often intense. Consequently, packagers are extremely cost sensitive. Packagers are also coming to grips with the ever increasing problems of waste plastic disposal. Plastic packages are coming under sharp criticism because of their relatively short useful life, their relatively long decomposition time, and their growth as a waste product. These problems are in addition to the normal challenges of providing an attractive, useful package for a growing diversity of products. Thus, clamshell package manufacturers are being asked to balance manufacturing needs, customers' desires and environmental concerns on a scale never before imagined.
To complicate matters, the materials useful for forming clamshell packages are often unacceptable for one reason or another. For example, polyvinyl chloride ("PVC") makes an excellent clamshell package.
The material is relatively inexpensive, clear, tough, durable and easy to seal shut using a heat sealing process. PVC is often, however, perceived to be environmentally unfriendly. Therefore, there is pressure on manufacturers to use alternative materials.
Polyethylene terephthalate ("PET"), such as "APET", can be used for clamshell packages. PET, while more expensive than PVC, is clear, durable and recyclable. However, PET cannot be easily heat sealed or solvent sealed and this limits its broad applicability.
PET derivatives such as a glycol-containing co-polyester developed by Eastman Chemical ("PETG") may be used in place of PET. PETG is considerably easier to heat and solvent seal than is PET. PETG is, however, relatively expensive. As such, there are many packaging '' 2~C~287 applications where PETG is simply too expensive to compete.
Currently, a number of legislative initiatives would limit the use of the word "recycled" or phrases such as "made with recycled materials" to plastic packages which include at least a certain percentage of "post-consumer recycled" plastic material, i.e. recycled plastic previously used in consumer applications. PET, by virtue of its extensive use in consumer product packaging, such as, for example, plastic beverage bottles, is abundant and post-consumer recycled PET is available in great volumes. Because of PET's prior consumer product usage, the material can satisfy requirements for use of "post-consumer recycled"
content. Therefore, post-consumer recycled PET can be utilized by packaging manufacturers to produce new packages which comply with pending legislative initiatives. As a result, packaging manufacturers benefit by being able to indicate that their package was made from recycled material. This is particularly important to many of today's environmentally conscious consumers. In addition, the cost of recycled PET is significantly less than virgin PET and is, in fact, competitive with virgin PVC.
On the other hand, there is relatively little post-consumer recycled PETG available. PETG is used in consumer packaging applications relatively infrequently and is not easily sorted out of mixed post-consumer recycled materials. There is a limited amount of PETG
recycled from industrial applications, but not enough for widespread use. As a practical matter, packaging manufacturers are forced to use industrial or virgin PETG for their packaging, particularly consumer packaging. These packages would not comply with many current legislative initiatives that would require post-consumer recycled material. When the cost of virgin PETG is added to the negative publicity of not providing ~ _4_ 2 ~ 2 ~ 7 recycled packages, PETG becomes a less and less attractive material for use.
A cost effective, clear, durable, sealable thermoformed package manufactured with sufficient post-consumer recycled material to allow it to indicate thatit is a "recycled package", and containing sufficient recyclable materials so as to be characterized as "recyclable", has been, to date, an unobtainable goal.
The present invention provides such a package.
In Europe, other non-thermoformed cartons such as those normally cut from a blank and folded and glued have been made utilizing a co-extruded plastic sheet comprised of a middle layer of PET and outer layers of PETG. This material was used because PETG, unlike PET, is more easily glued by the use of conventional solvents. Additionally, this co-extruded material could better utilize the advantages of "slip" agents to facilitate the handling of sheets of this material.
Slip agents, when used in sufficient concentration, allow sheets of extruded material to overcome blocking problems normally associated with both PET and PETG
sheets. Blocking is the binding of sheets of material by "friction-like" forces. Normally, sheets of plastic material rest in a feed device which feeds individual sheets into a box cutting, box folding, and/or box gluing apparatus. Blocking tends to make individual sheets stick together, resulting in problems of feeding material into the appropriate apparatus. Slip agents added to prevent blocking have been used in connection with PET and PETG extruded monolayers for some time.
However, the concentration of slip agents necessary to prevent blocking can cause discoloration. When slip agents are included only in the thin outer layers of the present co-extruded PET and PETG sheets, the resultant discoloration is so negligible that it is acceptable.
The problems of box manufacturing are different than the problems facing clamshell package manufacturers. The present inventor has realized that a 21~92~)7 co-extruded sheet of PET and PETG can be used to produce thermoformed packages with great benefit. In fact, in accordance with the present invention, thermoformed packages can be produced with all of the advantages of recycled PET or PETG alone with virtually none of their disadvantages. The thermoformed packages eliminate the need for the use of environmentally unfavorable products such as polyvinyl chloride. The cost of the overall package is greatly reduced relative to the cost of a similarly sized package made only of PETG. The packages are readily heat sealable. Furthermore, the strength, durability and cost savings realized from the use of PET, especially recycled PET, are preserved. Still further, slip agents can be employed and sufficiently clear packages are obtainable. Thus, packages made in accordance with the present invention are competitive in a much larger segment of the container market than previous containers.
The inventor has also realized that thermoformed packages of this material can be formulated such that despite the use of PETG, the overall thermoformed package can be classified as containing sufficient "post-consumer recycled" material to comply with current legislation. Thus, thermoformed clamshell packages which can be identified as "made from recycled materials", which are often themselves recyclable, and which are sufficiently inexpensive so as to encourage widespread adoption, can be produced.
It is one object of the present invention to provide a process of producing a thermoformed heat sealed plastic package which can be produced from recycled material and which are, themselves, classifiable as post-consumer recyclable.
Another object of the present invention is the provision of a process and package which are sufficiently cost effective so as to encourage widespread adoption and use by the packaging industry, ~ ~ C ~ 2 ~ 7 _ 6 thereby promoting the goals of conservation and the environment.
Another object of the present invention is the provision of thermoformed containers which can be heat sealed and methods of their production in a cost effective manner.
In accordance with these and other objects which will be readily appreciated by those of ordinary skill in the art, there is provided a process for producing a heat sealed plastic package. The process includes thermoforming a container from a co-extruded multi-layered sheet, the sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material.
The container has a cavity for storage therein, and a first flange, the first flange having an engaging surface disposed to engage a cover. The container is thermoformed such that the second layer of heat sealable polymeric material forms the engaging surface of the first flange. The process also includes providing a cover including a flange engaging surface having a layer of heat sealable polymeric material. Finally, the process involves sealing the cover to the container so as to enclose the cavity by heat sealing at least a portion of the flange engaging surface of the cover to the engaging surface of the first flange.
In one embodiment, the cover is composed of a co-extruded multi-layered sheet, the sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material, wherein the second layer forms the flange engaging surface.
In another embodiment, the cover is a second thermoformed container composed of a co-extruded multi-layered sheet, the sheet having a first layer of asubstantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material. The second container also has a cavity for storage formed ~9287 ~

therein and a second flange, the second flange having an engaging surface disposed to engage the engaging surface of the first flange. This engaging surface is the flange engaging surface of the cover. The second container is thermoformed such that the second layer of heat sealable polymeric material forms the engaging surface of the second flange.
In yet another embodiment, the cover is composed of a co-extruded multi-layered sheet, the sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material. In this particular embodiment, the sheet, and consequently the cover, are substantially flat.
In still another embodiment, the cover is connected to the container along at least one side to provide a hinge.
In accordance with another aspect of the present invention, there is also provided a heat sealable plastic package which contains sufficient post-consumer recycled plastic to be classifiable as being made from recycled material comprising a thermoformed container, the container being constructed from a co-extruded multi-layered sheet, the sheet including a first layer of a substantially non-heat sealable PET material which includes post-consumer recycled PET material and a second layer of heat sealable polymeric material, the container having a cavity for storage therein, the container including a first flange, the first flange having an engaging surface disposed to engage a cover, the container being thermoformed such that the second layer of heat sealable polymeric material forms the engaging surface of the first flange, and a cover including a flange engaging surface, the flange engaging surface including a layer of heat sealable polymeric material, so that the cover and the container can be heat sealed together to enclose the cavity by heat sealing at least a portion of the flange engaging surface of the cover to the engaging surface of the first .,~

7 ~

-7a-flange of the container, wherein the total amount of the post-consumer recycled polymeric material, as a percentage of the total plastic material used in the package, is sufficient to render the package classifiable as made from recycled material.

~' ~, ~ 3~ 7 _ -8-In one embodiment, the cover is composed of a co-extruded multi-layered sheet, the sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material, the second layer forming the flange engaging surface.
In another embodiment, the cover is a second thermoformed container. The container is constructed of a co-extruded multi-layered sheet, the sheet having a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material. The second container has a cavity for storage formed therein and a second flange. The second flange has an engaging surface disposed to engage the engaging surface of the first flange. Again, when the cover is a second container, as in this embodiment, the engaging surface of the second flange is the flange engaging surface of the cover. The second container is thermoformed such that the second layer of heat sealable polymeric material forms the engaging surface of the second flange.
In another embodiment, the cover is composed of a co-extruded multi-layered sheet, the sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material. The sheet, and consequently the cover, are substantially flat.
The cover may also be formed such that it is connected to the container through a hinge.
In accordance with a particularly preferred aspect of the present invention, there is provided a heat sealable plastic package which includes a thermoformed container, the container being constructed from a co-extruded multi-layered sheet, the sheet including a first layer of a mixture of virgin PET and greater than about 10 percent post-consumer recycled PET. The second layer is composed of PETG. The first layer has a thickness of between about 4 and

2~ ~S2~7 g about 40 mils and the second layer having a thickness of between about 0.5 and about 20 mils. The container has a cavity for storage therein and a first flange. The first flange has an engaging surface disposed to engage a cover. The container is thermoformed such that the second layer of PETG forms the engaging surface of the first flange.
The package includes a cover having a flange engaging surface having a layer of PETG.
The cover and the container are sealable so as to enclose the cavity by heat sealing at least a portion of the flange engaging surface of the cover to the engaging surface of the first flange.
The present invention provides thermoformed packages and method of their production. Through the use of the present invention, highly cost effective, heat sealable, thermoformed packages can be produced.
Heat sealing is particularly advantageous to packaging manufacturers since providing an effective seal to a thermoformed package is often either difficult, or requires the use of costly material. The present invention also provides a package which can be instrumental in encouraging the industry to make better use of recycled materials by offering packages made from those materials which will themselves be compliant with current legislative initiatives regarding recycling. As such, packaging manufacturers will benefit from the good will attendant to labeling their packages as being both recyclable, and derived from recyclable material.
Finally, the practice of the present invention allows packaging manufacturers to be socially and environmentally conscious while, at the same time, meeting the needs of the industries they serve.
In accordance with another aspect of the present invention, there is provided a heat sealable plastic package including a thermoformed container having a cavity for storage therein, and a first flange, the first flange having an engaging surface disposed to 21~ 7 engage a cover; and a cover including a flange engaging surface. The cover and the container can be heat sealed together to enclose the cavity by heat sealing at least a portion of the flange engaging surface of the cover to the first flange of the container. At least one of the cover or the container is constructed from a co-extruded multi-layered sheet. The sheet includes a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material.
The other of the cover or the container is constructed of at least one layer of heat sealable polymeric material.
In another aspect of the present invention, the heat sealable plastic package just described includes a container which is constructed from the co-extruded multi-layered sheet and a cover which is constructed from at least one layer of heat sealable material. Alternatively, the heat sealable plastic package can include a cover which is constructed from the co-extruded multi-layered sheet and a container which is constructed from at least one layer of a heat sealable material.
More preferably, at least one layer of heat sealable material is a single layer of, for example, PETG or chemically modified PET.
Preferred embodiments of the present invention will be described in greater detail with reference to the accompanying drawings, wherein like members bear like reference numerals and wherein:
Fig. 1 is a perspective view of a clamshell package in accordance with the present invention wherein the cover is composed of a colored sheet which is substantially flat.
Fig. 2 is a perspective view of the package of Fig. 1 with the cover being peeled away from the container.
Fig. 3 is a perspective view of another embodiment of a clamshell package in accordance with the -11- hi~928r7 present invention wherein the cover is connected to the container of the package along at least one side to provide a hinge.
Fig. 4 is a perspective view of the package of Fig. 3 in an open position so as to allow access to the cavity.
Fig. 5 is a perspective view of another clamshell package in accordance with the present invention wherein the cover is a second thermoformed container.
Fig. 6 is a perspective view of the thermoformed clamshell package of Fig. 5 with the container and cover separated to reveal the contents thereof.
The clamshell packages of the present invention can take a wide variety of shapes, sizes and configurations. For simplicity, however, three types will be discussed herein. The first type of clamshell package illustrated in Figs. 1 and 2 comprises a container having a cover or backing member comprised of a substantially flat sheet.
With reference to Fig. 1, the sealed clamshell container 10 in accordance with this aspect of the present invention includes a container 12 and a cover 20. Both the container 12 and the cover 20 are preferably produced from sheets of co-extruded multi-layered sheets. Each sheet includes a first layer of substantially non-heat sealable polymeric material and a second layer of a heat sealable polymeric material. As described in more detail herein, the first layer is typically PET and the second layer is typically PETG.
The material used to thermoform the container 12 and the cover 20 may be, but need not be, identical in composition, in content of recycled material, and/or in thickness. A three layered co-extruded material may also be used whereby the substantially non-heat sealable material is sandwiched between two layers of generally heat sealable material.

2~ 7 As shown in more detail in Fig. 2, the container 12 includes a cavity 14 in which material is stored. Container 12 includes a first flange 16 which, in this embodiment, completely surrounds the aperture or entranceway to container 12. The first flange 16 includes an engaging surface 18 which is disposed such that it can directly engage cover 20. As cover 20 and container 12 are to be heat sealed to each other in accordance with the processes of the present invention, it is necessary that the engaging surface 18 be composed of the second layer of heat sealable polymeric material, typically PETG. Usually, this means that the inside of container 12, i.e. the layer which will contact the contents of the container, is composed of the second layer of heat sealable polymeric material.
Cover 20 includes a flange engaging surface 22. The flange engaging surface 22 of cover 20 is brought into intimate contact with the engaging surface 18 of first flange 16 of container 12 before container 12 and cover 20 are sealable to one another.
As it is preferred in accordance with the present invention that cover 20 and container 12 be heat sealed to one another, it is usually necessary that the flange engaging surface 22 of cover 20 also be composed of the second layer of heat sealable polymeric material, namely PETG. In this way, when cover 20 and container 12 are brought together such that engaging surface 18 and flange engaging surface 22 are actually disposed adjacent one another and in intimate contact, two layers of substantially heat sealable material are disposed such that a heat seal can be formed.
In accordance with one aspect of the present invention, cover 20 is substantially flat.
"Substantially flat" as used herein does not mean that cover 20 must be a totally flat plane.
The second type of clamshell package is illustrated in Figs. 5 and 6 and comprises two independently thermoformed members whose peripheries are ' 21~92~7 placed in intimate contact with each other and then sealed. As illustrated in Fig. 6, it is possible that both the container and the cover are substantially identically shaped. However, that need not be the case, 5 especially with regard to the shape of the cavity.
As illustrated in Fig. 5, package 30 in accordance with this aspect of the present invention results from the joining of a container 32 and a cover 40. However, unlike package 10 illustrated in Fig. 1, cover 40 is not a substantially flat sheet.
Rather, cover 40 has been thermoformed into a specific shape. In this particular instance, cover 40 is identically shaped or, more correctly, is the mirror image of container 32. Of course, the size and shape of 15 container 32 and cover 40 can vary widely.
As illustrated in Fig. 6, container 32 includes a cavity 34 for retaining items such as, in this case, batteries 60. Container 32 includes a first flange 36, the first flange including an engaging 20 surface 38 for engaging cover 40. In a particularly preferred embodiment of the process of the present invention, container 32 and cover 40 are to be heat sealed to one another. Therefore, the engaging surface 38 of first flange 36 iS composed of the second 25 heat sealable layer of the co-extruded material used to form container 32.
Cover 40 is a second thermoformed container thermoformed from a second co-extruded multi-layered sheet. Like the co-extruded multi-layered sheet 30 thermoformed to produce container 32, the co-extruded multi-layered sheet used to thermoform cover 40 includes a first layer of substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material. Cover 40 also referred to herein as 35 a second container 40 includes a cavity 44 and a second flange 46. Second flange 46 has an engaging surface 48 which is disposed to engage engaging surface 38 of 2 G~?.~2~7 container 32. In this context, engaging surface 48 forms the flange engaging surface of cover 40.
After material to be packaged in thermoformed package 30 is placed into one or more of the cavities 34 and/or 44, container 32 and second container or cover 40 are brought into intimate contact. At that point, the engaging surface 48 of the second flange 46 engages the engaging surface 38 of the first flange 36 of container 32. Both the engaging surface 48 and the engaging surface 38 are composed of the second heat sealable layer of the co-extruded material used in accordance with the present invention and, therefore, these two are disposed such that they may be heat sealed together. As shown in Figs. 5 and 6, the thermoformed packages in accordance with the present invention may also include a hole, cut out, aperture or hanging means 50 which may be used to suspend the completed package 30 from a pegboard like display.
The third form of clamshell package includes a container and cover which are intimately connected to one another. Generally, a single sheet of material is thermoformed such that it contains the cover and the container. The sheet can then be folded, creased or bent such that the cover and container are brought into intimate contact with each other. See Figs. 3 and 4.
Of course, as illustrated in Fig. 3, this type of clamshell package may further include additional structure forming a specific hinge. As shown in Fig. 3, clamshell package 70 includes a container 72 and a cover 80.
As shown in Fig. 4, container 72 and cover 80 are attached to one another, or, more correctly, integrally formed such that they are attached even before package 70 is sealed. As previously described, in a preferred embodiment, both container 72 and cover 80 are thermoformed from the same co-extruded sheet of material. Thereafter, the sheet is folded, creased or bent such that the cover and container are brought into intimate contact with each other such that they can be sealed. More preferably, additional structure may be included so as to provide a hinge 90.
Hinge 90 allows for the repeated engagement and disengagement of container 72 and cover 80. In addition, hinge 90 as shown in Fig. 3 correctly aligns first flange 76 and second flange 86 such that they may be easily sealed together.
As illustrated in Fig. 4, container 72 includes a cavity 74 and a first flange 76. As previously described, first flange 76 includes an engaging surface 78 which is composed of a second heat sealable layer of the co-extruded sheet material used to form container 72.
Cover 80 includes a cavity 84 and a second flange 86. Second flange 86 includes an engaging surface 88 also composed of the second heat sealable layer of the co-extruded material used to form package 70. Engaging surface 88 is the flange engaging surface of cover 80. When cover 80 is folded atop of container 72 at hinge 90, engaging surface 78 of first flange 76 of container 72 is brought into intimate contact with engaging surface 88 of second flange 86 of cover 80 such that container 72 and cover 80 may be sealed and, more preferably, heat sealed together. In the embodiment shown in Figs. 3 and 4, cavity 84 is larger than cavity 74 and encompasses not only cavity 74, but also the structure which defines cavity 74.
Also as shown in Figs. 3 and 4, clamshell packages in accordance with the present invention can be provided with a cutaway 92 and a recessed ridge structure 94 for providing access of a digit so as to aid in easily manipulating and opening and closing package 70. Other similarly functioning structures such as tabs, cutouts, and the like are also contemplated.
The sheet material used to form at least a portion of the thermoformed clamshell packages of the ' 21 ~g2~7 present invention comprises a plurality of co-extruded layers. The first layer is composed of a substantially non-heat sealable polymeric material. It should be understood that the term "substantially non-heat S sealable polymeric material" as used in the first layer generally refers to PET. Of course, this term can also refer to other types of polymers which are difficult to heat seal.
The PET used for the thermoformed packages of the present invention may be virgin or new. However, new PET is more expensive than recycled PET. Moreover, the use of virgin material may severely limit the ability of a package manufacturer to advertise the package as being "recycled" or "made from recycled material". Therefore, it is preferred that at least about 10% of the PET used for the first layer be post-consumer recycled material. More preferably, the first layer includes greater than 25% post-consumer recycled PET.
The greater the content of recycled PET, the greater the benefits to the manufacturer in terms of cost and compliance with various legislative initiatives. Furthermore, the greater the amount of recycled material used in the first layer, the greater the benefits to the environment. Therefore, it is particularly preferred in accordance with the present invention to utilize at least 50% post-consumer recycled PET in the thermoformed packages of the present invention. Ideally, about 100% of the first layer is post-consumer recycled PET. Of course, under some circumstances, it may be necessary to restrict the amount of recycled PET utilized because of particularly demanding packaging requirements.
Almost any type or grade of PET may be used.
However, PET resulting from certain extruding processes is preferred. For example, in conventional recycling procedures, PET containers, for example, are chopped into flake, melted, extruded as a cord or ribbon, sliced ~ ~ 3 ~ ~ ~ 7 into beads, and then re-extruded. This process provides a great deal of uniformity to the recycled material.
However, it also places the material under a good deal of stress and increases the cumulative heat history of the material. Over time, and as the material is repeatedly recycled, such extrusion processes may lessen the clarity, durability, and appearance of the material.
Therefore, it is particularly preferred in accordance with the present invention be use a material which has been extruded directly from flake into a sheet. This eliminates at least one cutting and extrusion step from the process and vastly reduces the stress and heat exposure of the material. PET produced in accordance with this process can be obtained from Genesis Plastics, Charleroi, Pennsylvania 15022, a division of Nicon Plastics, Inc. under the trademark "GENEX".
The thickness of the first layer will depend upon the particular application. Weight, cost, workability, strength, and clarity must all be balanced.
Although a wide variety of thicknesses are possible, the first layer of substantially non-heat sealable polymeric material generally ranges in thickness from between about 4 to about 40 mils thick. More preferably, the first layer in accordance with the present invention has a thickness of between about 6 and about 25 mils and, most preferably, between about 8 and about 15 mils.
The second substantially heat sealable layer is generally composed of PETG. Of course, other relatively heat sealable materials such as chemically modified PET, PVC, and certain urethanes can also be used. Chemically modified PET is relatively expensive and is composed of PET that has been treated so as to render it relatively heat sealable. PVC, while inexpensive, may effect the recyclability of the resulting package.
Because of the cost involved, it would be advantageous to use 100% recycled heat sealable material such as PETG to form the second layer. However, due to the general lack of recycled PETG and, in particular, post-consumer recycled PETG, it is usually necessary that the second layer be composed of a mixture of recycled and virgin PETG or virgin PETG alone. PETG is available from Eastman Chemical, Kingsport, Tennessee, under the trademark "KODAR" PETG copolyester 6763.
The thickness of the PETG containing second layer can also vary widely. Preferably, in accordance with the present invention, the second layer of substantially heat sealable material can have a thickness of between about 0.5 and about 20 mils. More preferably, the thickness of the second layer ranges from between about 1 to about 4 mils and, most preferably, between about 1 and about 2 mils.
In accordance with the present invention, it is particularly advantageous to minimize the thickness of the second heat sealable layer. Most of the structural integrity of the thermoformed package of the present invention comes from the first layer. A major reason for including PETG in a co-extruded material used to form the package is its ability to be heat sealed relatively easily when compared to, for example, PET.
As such, and because of its cost, the amount of PETG
used can be minimized. Moreover, if the relative proportion of PETG in the thermoformed package of the present invention is kept to a minimum, the predominance of post-consumer recyclable PET relative to the amount of PETG in the resulting container will allow the entire package to be classified as post-consumer recyclable.
As previously discussed, it is not necessary that the cover and container be produced from identical material. The cover could be produced from a layer of virgin PET having one thickness and a layer of 10%
recycled PETG having a second thickness while the container could be produced from a first layer of 100%
recycled PET which is thicker than the first layer of the cover. The second layer of the container could be -19- 2~C92~7 produced from virgin PETG which is thinner than the second layer of the cover.
The third layer is, in accordance with the present invention, generally of the same thickness and composition as the second layer. Of course, there is no reason why the second and third layers could not be different in terms of thickness and material. For example, the second layer by virtue of its role in heat sealing may be purposefully thicker than the third layer so as to provide more material in which to effectuate an effective seal.
Both PETG and PET can be, and usually are, clear when used in thermoformed clamshell packages.
However, both materials may be colored. This may be particularly useful in conjunction with a clamshell package having a substantially flat cover member which can be made of a particular color so as to provide contrast to the package's contents. See Figs. 1 and 2.
Furthermore, both PET and PETG can be imprinted.
Therefore, it is possible to imprint letters, words, advertising copy, titles, and instructions, as well as figures on the thermoformed package.
In the most preferred embodiments described herein, and, as a general rule, it is preferable that both the cover and the container of the present invention be constructed of the co-extruded multi-layered sheets described herein. Of course, however, that is not essential. It is possible in accordance with the present invention that either the cover or the container, but not both, be composed of at least a single layer of heat sealable material such as PETG or chemically modified PET. It is possible that this at least one layer of heat sealable polymeric material is a co-extruded material different than that described generally herein. More preferably, however, the cover or the container is manufactured from a single layer or monolayer of extruded heat sealable polymeric material having a thickness of between about 4 and -20- 2 ~ ~ 9 2 ~ 7 about 80 mils at most and, more preferably, a thickness of between about 8 and about 30 mils. The heat sealable material is as previously described.
Packages so constructed are not as advantageous as other previously described, as generally thicker layers of more expensive materials are required.
In addition, the use of heat sealable materials, such as PVC, may eliminate other advantages such as recyclability. The cover or container which is not constructed from the at least one layer of heat sealable material as described herein is composed of the co-extruded multi-layered sheet material previously described.
Both the processes of co-extrusion and thermoforming are well known in the plastics art.
Extrusion can be defined as converting plastic powder or granules into a continuous uniform melt and forcing this melt through a die which yields a desired shape. The melt material must then be cooled back to its solid state as it is held in the desired shape. In accordance with the present invention, the desired shape is that of a sheet or film.
There are a wide variety of extruding devices used in plastics extrusion. For example, a single-screw extruder can be used. Single-screw extruders are amongst the most common and versatile extruders used in the industry today because of their ability to process a wide range of materials with great cost advantage. A
more complete discussion of extrusion can be found in Chapter 4 of the 1991 "Modern Plastic Encyclopedia", Volume 67, No. 11 published by McGraw-Hill of Hightstown, New Jersey. The entire text of Chapter 4 entitled "Primary Processing" is hereby incorporated by reference.
Thermoforming, or the deforming of a thermoplastic sheet with heat and pressure (or vacuums) to force the hot sheet against a mold base, is a common method of converting thermoplastic into useful products.

2~ ~a~87 ~ -21-Thermoforming is an extension of the original technologies used to forge metal sheets and, in some cases, paper. All of the variations and forming techniques used in thermoforming have common ground in S getting movement or stretching of a heated sheet of plastic by applying vacuum, air pressure, or mechanical drawing or a combination of these three thereto. A more complete discussion of thermoforming can be found in pages 332-336 of the aforementioned Modern Plastics Encyclopedia. See also Plastic Engineering Handbook of the Society of the Plastic Industry, Inc., Fourth Edition, Edited by Joel Frados, available from Van Nostrand Reinhold Company, Copyright 1976 and, in particular, pages 156-203 and 272-325. The text of both are hereby incorporated by reference.
The foregoing will be better understood with reference to the following examples. The examples are for the purposes of illustration. They are not to be considered limiting as to the scope and nature of the present invention.
Example 1 Co-extruded material having three layers as described herein is unwound from a roll at an unwind station of a thermoforming machine such as those commonly available from Sencorp. A sheet from the roll is preheated to a temperature of between about 265'F and about 325'F. The sheet is then moved into a thermoforming press where a mold having the desired shape of the container is heated to between about 130'F
and about 140'F. The mold is brought into intimate contact with the preheated sheet and the sheet is stretched around the mold to form the desired shape.
The mold is then withdrawn and the deformed sheet is moved to a trim press where the container is cut from the sheet. The material between the formed container walls and the cut forms the flange. This flange will be used in sealing a container to a cover. Thereafter, the trimmed thermoformed container is moved to a removal and 21~2~7 stacking station where it is separated from the remainder of the sheet and conveniently stacked with other similarly thermoformed components.
Example 2 A thermoformed container and cover produced in accordance with the process of Example 1 are filled with material and brought into intimate contact such that the engaging surface of the flange of the container is in intimate contact with the flange engaging surface of the cover. The assembly is then sealed in, for example, a Kabar high frequency RF press (15 kw press). First, a heated platen having a temperature of approximately 200'F is lowered onto the periphery of the package (the flange) for approximately 1 1/2 seconds to initially hold the container and cover in place. The platen lightly presses the flange of the cover and flange of the container together to begin the sealing process. Then high frequency RF is applied for approximately 3.5 seconds to complete the heat sealing process. During some RF sealing procedures, excess flange is simultaneously cut in a process known in the art as "tear sealing". When tear sealing, the platen is lowered to begin the heat sealing process, RF is subsequently applied, and the outer periphery of the now formed package is cut away and removed.
The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. The invention which is intended to be protected herein, however, is not to be construed as limited to the particular embodiments disclosed, since these are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others without parting from the spirit and scope of the invention.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for producing a heat sealed plastic package comprising the steps of thermoforming a container from co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material, said container having a cavity for storage therein, said container including a first flange, said first flange having an engaging surface disposed to engage a cover, said container being thermoformed such that said second layer of heat sealable polymeric material forms the engaging surface of said first flange; providing a cover including a flange engaging surface having a layer of heat sealable polymeric material; and sealing said cover to said container so as to enclose said cavity by heat sealing at least a portion of said flange engaging surface of said cover to said engaging surface of said first flange.

2. The process of producing the heat sealed plastic package of claim 1, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material, wherein said second layer forms said flange engaging surface.

3. The process of producing the heat sealed plastic package of claim 1, wherein said cover is a second thermoformed container composed of a co-extruded multi-layered sheet, said sheet having a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material, said second container having a cavity for storage formed therein, said second container including a second flange, said second flange having a flange engaging surface disposed to engage said engaging surface of said first flange, and said second container being thermoformed such that said second layer of heat sealable polymeric material forms the flange engaging surface of said second flange.

4. The process of producing the heat sealed plastic package of claim 1, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material, said sheet being substantially flat.

5. The process of producing the heat sealed plastic package of claim 1, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material, said cover is connected to said container along at least one side to provide a hinge.

6. The process of producing the heat sealed plastic package of claims 1 through 5, wherein said first layer has a thickness of between about 4 and about 40 mils.

7. The process of producing the heat sealed plastic package of claim 6, wherein said first layer has a thickness of between about 6 and about 25 mils.

8. The process of producing the heat sealed plastic package of claim 7, wherein said first layer has a thickness of between about 8 and about 15 mils.

9. The process of producing the heat sealed plastic package of claim 1, wherein said second layer has a thickness of between about 0.5 and about 20 mils.

10. The process of producing the heat sealed plastic package of claim 9, wherein said second layer has a thickness of between about 1 and about 4 mils.

11. The process of producing the heat sealed plastic package of claim 10, wherein said second layer has a thickness of between about 1 and about 2 mils.

I 12. The process of producing the heat sealed plastic package of claim 1, wherein said first layer is composed of PET.

13. The process of producing the heat sealed plastic package of claim 1, wherein said first layer is composed of a mixture of virgin PET and post consumer recycled PET.

14. The process of producing the heat sealed plastic package of claim 13, wherein said mixture contains greater than 10 percent post-consumer recycled PET.

15. The process of producing the heat sealed plastic package of claim 14, wherein said mixture contains greater than 25 percent post-consumer recycled PET.

16. The process of producing the heat sealed plastic package of claim 15, wherein said mixture contains at least 50 percent post-consumer recycled PET.

17. The process of producing the heat sealed plastic package of claim 15, wherein said first layer is composed of 100 percent post-consumer recycled PET.

18. The process of producing the heat sealed plastic package of claim 1, wherein said second layer is composed of PETG.

19. The process of producing the heat sealed plastic package of claim 18, wherein said second layer is a mixture of virgin PETG and recycled PETG.

20. The process of producing the heat sealed plastic package of claim 1 further comprising a third layer of a polymeric material co-extruded with said multi-layered sheet, said third layer being disposed such that said first layer is sandwiched between said second and said third layer.

21. The process of producing the heat sealed plastic package of claim 20, wherein said third layer is composed of heat sealable polymeric material.

22. The process of producing the heat sealed plastic package of claim 21, wherein said second layer of heat sealable polymeric material and said third layer of heat sealable polymeric material are composed of the same polymeric material.

23. The process of producing the heat sealed plastic package of claim 21, wherein said third layer has a thickness of between about 0.5 and about 20 mils.

24. The process of producing the heat sealed plastic package of claim 23, wherein said third layer has a thickness of between about 1 and about 4 mils.

25. The process of producing the heat sealed plastic package of claim 24, wherein said third layer has a thickness of between about 1 and about 2 mils.

26. The process of producing the heat sealed plastic package of claim 21, wherein said third layer is composed of PETG.

27. The process of producing the heat sealed plastic package of claim 26, wherein said third layer is a mixture of virgin PETG and recycled PETG.

28. The process of producing the heat sealed plastic package of claim 1, wherein said cover is sealed to said package using high frequency RF.

29. The process of producing the heat sealed plastic package of claim 13, wherein said PET was produced using a post-consumer recycled material extruded directly from flake into a sheet.

30. The process of producing the heat sealed plastic package of claim 4, wherein said substantially flat cover is composed of a colored co-extruded multi-layered sheet.

31. The process of producing the heat sealed plastic package of claim 4 further comprising the step of imprinting letters or figures on said substantially flat cover.

32. A process for producing a heat sealed plastic package comprising the steps of thermoforming a container from co-extruded multi-layered sheet, said sheet including a first layer of PET and a second layer of PETG, said container having a cavity for storage therein, said container including a first flange, said first flange having an engaging surface disposed to engage a cover, said container being thermoformed such that said second layer forms the engaging surface of said first flange; providing a cover including a flange engaging surface having a layer of PETG; and sealing said cover to said container so as to enclose said cavity by heat sealing at least a portion of said flange engaging surface of said cover to said engaging surface of said first flange.

33. The process of producing the heat sealed plastic package of claim 32, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of PET and a second layer of PETG, wherein said second layer forms said flange engaging surface.

34. The process of producing the heat sealed plastic package of claim 32, wherein said cover is a second thermoformed container composed of a co-extruded multi-layered sheet, said sheet having a first layer of PET and a second layer of PETG, said second container having a cavity for storage formed therein, said second container including a second flange, said second flange having a flange engaging surface disposed to engage said engaging surface of said first flange, and said second container being thermoformed such that said second layer of PETG forms the flange engaging surface of said second flange.

35. The process of producing the heat sealed plastic package of claim 32, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of PET and a second layer of PETG, said sheet being substantially flat.

36. The process of producing the heat sealed plastic package of claim 32, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of PET and a second layer of PETG, said cover being connected to said container along at least one side so as to provide a hinge.

37. A heat sealable plastic package which contains sufficient post-consumer recycled plastic to be classifiable as being made from recycled material comprising:
a thermoformed container, said container being constructed from a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable PET material which includes post-consumer recycled PET
material and a second layer of heat sealable polymeric material, said container having a cavity for storage therein, said container including a first flange, said first flange having an engaging surface disposed to engage a cover, said container being thermoformed such that said second layer of heat sealable polymeric material forms the engaging surface of said first flange; and a cover including a flange engaging surface, said flange engaging surface including a layer of heat sealable polymeric material; so that said cover and said container can be heat sealed together to enclose said cavity by heat sealing at least a portion of said flange engaging surface of said cover to said engaging surface of said first flange of said container, wherein the total amount of said post-consumer recycled polymeric material, as a percentage of the total plastic material used in the package, is sufficient to render the package classifiable as made from recycled material.

38. The heat sealable plastic package of claim 37, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material which includes post-consumer recycled material and a second layer of heat sealable polymeric material, said second layer forming said flange engaging surface.

39. The heat sealable plastic package of claim 37, wherein said cover is a second thermoformed container, said container being constructed of a co-extruded multi-layered sheet, said sheet having a first layer of a substantially non-heat sealable polymeric material which includes post-consumer recycled material and a second layer of heat sealable polymeric material, said second container having a cavity for storage formed therein, said second container including a second flange, said second flange having a flange engaging surface disposed to engage said engaging surface of said first flange, said second container being thermoformed such that said second layer of heat sealable polymeric material forms the flange engaging surface of said second flange.

40. The heat sealable plastic package of claim 37, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material which includes post-consumer recycled material and a second layer of heat sealable polymeric material, said sheet being substantially flat.

41. The heat sealable plastic package of claim 37, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material which includes post-consumer recycled material and a second layer of heat sealable polymeric material, wherein said cover is connected to said container through a hinge.

42. The heat sealable plastic package of claim 37, wherein said first layer has a thickness of between about 4 and about 40 mils.

43. The heat sealable plastic package of claim 42, wherein said first layer has a thickness of between about 6 and about 25 mils.

44. The heat sealable plastic package of claim 43, wherein said first layer has a thickness of between about 8 and about 15 mils.

45. The heat sealable plastic package of claim 37, wherein said second layer has a thickness of between about 0.5 and about 20 mils.

46. The heat sealable plastic package of claim 45, wherein said second layer has a thickness of between about 1 and about 4 mils.

47. The heat sealable plastic package of claim 46, wherein said second layer has a thickness of between about 1 and about 2 mils.

48. The heat sealable plastic package of claim 37, wherein said first layer is composed of PET.

49. The heat sealable plastic package of claim 37, wherein said first layer is composed of a mixture of virgin PET and post-consumer recycled PET.

50. The heat sealable plastic package of claim 49, wherein said mixture contains greater than 10 percent post-consumer recycled PET.

51. The heat sealable plastic package of claim 50, wherein said mixture contains greater than 25 percent post-consumer recycled PET.

52. The heat sealable plastic package of claim 51, wherein said mixture contains at least 50 percent post-consumer recycled PET.

53. The heat sealable plastic package of claim 37, wherein said first layer is composed of 100 percent post-consumer recycled PET.

54. The heat sealable plastic package of claim 37, wherein said second layer is composed of PETG.

55. The heat sealable plastic package of claim 54, wherein said second layer is a mixture of virgin PETG and recycled PETG.

56. The heat sealable plastic package of claim 37 further comprising a third layer of a polymeric material co-extruded with said multi-layered sheet, said third layer being disposed such that said first layer is sandwiched between said second and said third layer.

57. The heat sealable plastic package of claim 56, wherein said third layer is composed of heat sealable polymeric material.

58. The heat sealable plastic package of claim 57, wherein said second layer of heat sealable polymeric material and said third layer of heat sealable polymeric material are composed of the same polymeric material.

59. The heat sealable plastic package of claim 57, wherein said third layer has a thickness of between about 1 and about 20 mils.

60. The heat sealable plastic package of claim 59, wherein said third layer has a thickness of between about 1 and about 4 mils.

61. The heat sealable plastic package of claim 60, wherein said third layer has a thickness of between about 1 and about 2 mils.

62. The heat sealable plastic package of claim 57, wherein said third layer is composed of PETG.

63. The heat sealable plastic package of claim 62, wherein said third layer is a mixture of virgin PETG and recycled PETG.

64. The heat sealable plastic package of claim 37, wherein said cover is capable of being sealed to said package using high frequency RF.

65. The heat sealable plastic package of claim 49, wherein said PET was produced using a post-consumer recycled material extruded directly from flake into a sheet.

66. The heat sealable plastic package of claim 40, wherein said substantially flat cover is composed of a colored co-extruded multi-layered sheet.

67. The heat sealable plastic package of claim 40 further comprising imprinted letters or figures on said substantially flat cover.

68. The heat sealable plastic package of claim 37, wherein said cover and said container are heat sealed together.

69. A heat sealed plastic package manufactured in accordance with the process of claim 1.

70. A heat sealable plastic package comprising a thermoformed container, said container being constructed from a co-extruded multi-layered sheet, said sheet including a first layer of a mixture of virgin PET
and greater than 10 percent post-consumer recycled PET
and a second layer of PETG, said first layer having a thickness of between about 4 and about 40 mils and said second layer having a thickness of between about 0.5 and about 20 mils, said container having a cavity for storage therein, said container including a first flange, said first flange having an engaging surface disposed to engage a cover, said container being thermoformed such that said second layer of PETG forms the engaging surface of said first flange; a cover including a flange engaging surface having a layer of PETG; and said cover being sealable to said container so as to enclose said cavity by heat sealing at least a portion of said flange engaging surface of said cover to said engaging surface of said first flange.

71. The heat sealable plastic package of claim 70, wherein said cover is composed of a co-extruded multi-layered sheet, said sheet including a first layer of a mixture of virgin PET and greater than 10 percent post-consumer recycled PET and a second layer of PETG, said first layer having a thickness of between about 4 and about 40 mils and said second layer having a thickness of between about 0.5 and about 20 mils, said second layer forming said flange engaging surface.

72. The heat sealable plastic package of claims 70 or 71, further comprising a third layer of a polymeric material co-extruded with said multi-layered sheet, said third layer being disposed such that said first layer is sandwiched between said second and said third layer, said third layer being composed of PETG and having a thickness of between about 0.5 and about 20 mils.

73. The heat sealable plastic package of claim 72, wherein said cover and said container are heat sealed together.

74. A heat sealable plastic package comprising a thermoformed container having a cavity for storage therein, said container including a first flange, said first flange having an engaging surface disposed to engage a cover; and a cover including a flange engaging surface; said cover and said container being capable of being heat sealed together to enclose said cavity by heat sealing at least a portion of said flange engaging surface of said cover to said first flange of said container; wherein at least one of said cover and said container is constructed from at least one layer of heat sealable polymeric material and the other of said cover and said container is constructed from a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable polymeric material and a second layer of heat sealable polymeric material.

75. The heat sealable plastic package of claim 74, wherein said container is constructed from said co-extruded multi-layered sheet and said cover is constructed from at least one layer of heat sealable polymeric material.

76. The heat sealable plastic package of claim 74, wherein said cover is constructed from said co-extruded multi-layered sheet and said container is constructed from at least one layer of a heat sealable polymeric material.

77. The heat sealable plastic package of claim 74, wherein said cover is a second thermoformed container having a cavity for storage formed therein, said second container including a second flange, and said second flange disposed to engage said first flange of said first container.

78. The heat sealable plastic package of claim 74, wherein said cover is substantially flat.

79. The heat sealable plastic package of claim 74, wherein said cover is connected to said container through a hinge.

80. The heat sealable plastic package of claim 74, wherein said at least one layer of heat sealable polymeric material is a single layer.

81. The heat sealable plastic package of claim 80, wherein said single layer of heat sealable polymeric material is selected from the group consisting of PETG, chemically modified PET, PVC and urethane.

82. The heat sealable plastic package of claim 81, wherein said at least one layer of heat sealable polymeric material is PETG.

83. The heat sealable plastic package of claim 80, wherein said single layer of heat sealable material has a thickness of between about 4 and about 80 mils.

84. The heat sealable plastic package of claim 83, wherein said single layer of heat sealable material has a thickness of between about 8 and about 30 mils.

85. The heat sealable plastic package of claim 74, wherein said first layer has a thickness of between about 4 and about 40 mils.

86. The heat sealable plastic package of claim 85, wherein said first layer has a thickness of between about 6 and about 25 mils.

87. The heat sealable plastic package of claim 86, wherein said first layer has a thickness of between about 8 and about 15 mils.

88. The heat sealable plastic package of claim 74, wherein said second layer has a thickness of between about 0.5 and about 20 mils.

89. The heat sealable plastic package of claim 88, wherein said second layer has a thickness of between about 1 and about 4 mils.

90. The heat sealable plastic package of claim 89, wherein said second layer has a thickness of between about 1 and about 2 mils.

91. The heat sealable plastic package of claim 74, wherein said first layer is composed of PET.

92. The heat sealable plastic package of claim 74, wherein said first layer is composed of a mixture of virgin PET and post-consumer recycled PET.

93. The heat sealable plastic package of claim 92, wherein said mixture contains greater than 10 percent post-consumer recycled PET.

94. The heat sealable plastic package of claim 93, wherein said mixture contains greater than 25 percent post-consumer recycled PET.

95. The heat sealable plastic package of claim 94, wherein said mixture contains at least 50 percent post-consumer recycled PET.

96. The heat sealable plastic package of claim 95, wherein said first layer is composed of 100 percent post-consumer recycled PET.

97. The heat sealable plastic package of claim 74, wherein said second layer is composed of PETG.

98. The heat sealable plastic package of claim 97, wherein said second layer is a mixture of virgin PETG and recycled PETG.

99. The heat sealable plastic package of claim 74, further comprising a third layer of a polymeric material co-extruded with said multi-layered sheet, said third layer being disposed such that said first layer is sandwiched between said second and said third layer.

100. The heat sealable plastic package of claim 99, wherein said third layer is composed of heat sealable polymeric material.

101. The heat sealable plastic package of claim 100, wherein said second layer of heat sealable polymeric material and said third layer of heat sealable polymeric material are composed of the same polymeric material.

102. The heat sealable plastic package of claim 101, wherein said third layer has a thickness of between about 1 and about 20 mils.

103. The heat sealable plastic package of claim 102, wherein said third layer has a thickness of between about 1 and about 4 mils.

104. The heat sealable plastic package of claim 103, wherein said third layer has a thickness of between about 1 and about 2 mils.

105. The heat sealable plastic package of claim 100, wherein said third layer is composed of PETG.

106. The heat sealable plastic package of claim 105, wherein said third layer is a mixture of virgin PETG and recycled PETG.

107. The heat sealable plastic package of claim 37, wherein said cover and said container are heat sealed together.

108. The heat sealable plastic package of claim 74, wherein said cover and said container are heat sealed together.

109. A method of using post-consumer recycled plastic material comprising the steps of:
providing a non-heat sealable post-consumer recycled material;
co-extruding a first layer from said post-consumer recycled material and at least one second layer from a heat sealable polymeric material into a sheet, the amount of said post-consumer recycled material being sufficient to render the entire sheet classifiable as recycled; and thermoforming said co-extruded sheet into a heat sealable package.

110. The method of claim 109, wherein said first layer has a thickness of between about 4 and about 40 mils.

111. The method of claim 110, wherein said first layer has a thickness of between about 6 and about 25 mils.

112. The method of claim 111, wherein said first layer has a thickness of between about 8 and about 15 mils.

113. The method of claim 112, wherein said at least one second layer has a thickness of between about 0.5 and about 20 mils.

114. The method of claim 113, wherein said at least one second layer has a thickness of between about 1 and about 4 mils.

115. The method of claim 114, wherein said at least one second layer has a thickness of between about 1 and about 2 mils.

116. The method of claim 109, wherein said first layer is composed of a mixture of virgin PET and post-consumer recycled PET.

117. The method of claim 116, wherein said mixture contains greater than 10 percent post-consumer recycled PET.

118. The method of claim 117, wherein said mixture contains greater than 25 percent post-consumer recycled PET.

I

119. The method of claim 118, wherein said mixture contains at least 50 percent post-consumer recycled PET.

120. The method of claim 109, wherein said first layer is composed of 100 percent post-consumer recycled PET.

121. The method of claim 109, wherein said at least one second layer is composed of PETG.

122. The method of claim 121, wherein said at least one second layer is a mixture of virgin PETG and recycled PETG.

123. The method of claim 109, wherein said post-consumer recycled material is provided in flake form.

124. The heat sealable plastic package of claim 37 wherein said thermoformed container and said cover are capable of being RF sealed.

125. The heat sealable plastic package of claim 37 wherein said second layer of heat sealable polymeric material is composed of PETG.

126. The heat sealable plastic package of claim 37 wherein said second layer of heat sealable polymeric material of said container is capable of being directly sealed to said flange engaging surface of said cover.

127. The heat sealable plastic package of claim 125 wherein the amount of said PETG used in combination with said PET material will still allow said package to be recycled as post-consumer PET.

128. A heat sealable plastic package which contains post-consumer recycled plastic comprising:
a thermoformed container, said container being constructed from a co-extruded multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable PET material which is composed of a mixture of virgin PET and at least 10 percent post-consumer recycled PET and a second layer of a heat sealable polymeric material, said container having a cavity for storage therein, said container including a first flange, said :

first flange having an engaging surface disposed to engage a cover, said container being thermoformed such that said second layer of heat sealable polymeric material forms the engaging surface of said first flange; and a cover composed of a co-extruded, multi-layered sheet, said sheet including a first layer of a substantially non-heat sealable PET material which is composed of a mixture of virgin PET and at least 10 percent post-consumer recycled PET material and a second layer of heat sealable polymeric material, said second layer forming a flange engaging surface; so that said cover and said container can be heat sealed together to enclose said cavity by heat sealing at least a portion of said flange engaging surface of said cover to said engaging surface of said first flange of said container.

129. The heat sealable plastic package of claim 128, wherein said second layer is composed of PETG.

130. The heat sealable plastic package of claim 129, wherein said mixture contains greater than 25 percent post-consumer recycled PET.

131. The heat sealable plastic package of claim 130, wherein said mixture contains greater than 50 percent post-consumer recycled PET.

132. The heat sealable plastic package of claim 129, wherein said second layer is a mixture of virgin PETG
and recycled PETG.

133. The heat sealable plastic package of claim 129 wherein said thermoformed container and said cover is capable of being sealed.

134. The heat sealable plastic package of claim 129 wherein said second layer of heat sealable polymeric material of said container is capable of being directly sealed to said flange engaging surface of said cover.