Container with recycled plastic

A container incorporating post-consumer recycled ("PCR") plastic and a method of making that type of container. The container utilizes a layer of polypropylene or EVOH or a film of fluorinated polyethylene toward the interior from the recycled plastic to prevent contaminants from the latter entering the container's contents. When utilizing EVOH, the container usually has an additional layer of polyethylene or polypropylene covering the EVOH to prevent its deterioration by moisture. Making the container involves first composing a resin including the recycled plastic. Forming the various layers listed above produces a container that includes recycled plastic and a barrier to limit the migration of contaminants from the recycled material to the container's contents. This permits the use of the resulting containers for food. For a fluorinated polyethylene film, fluorination can occur either during or after the container's formation.

BACKGROUND 
Plastic containers, for an extensive period of time, have found widespread 
use in society for holding a vast array of goods. In fact, such containers 
have become so omni present that their disposal now poses a substantial 
problem. Society no longer wishes to place the used containers into the 
very limited landfill left to it. 
Accordingly, recent years have witnessed a substantial effort to recycle 
plastic containers. This would accomplish several desirable results. 
First, it will help save the limited resources of our planet for future 
generations. Furthermore, recycling will have the obvious effect of 
conserving the landfill that remains available. 
However, much plastic finds use in containers that hold food items. Most 
desirably, recycling must employ previously used plastic in new food 
containers. In fact, various legislative bodies are considering the 
requirement that a certain portion, generally around 25 percent, of all 
containers, including specifically those intended for food, must consist 
of recycled plastic. 
The problem with utilizing recycled plastic in food containers results from 
the fact that these containers have previously held all types of 
materials. Many of these materials, for one reason or another, constitute 
contaminants should they enter food items above a negligible 
concentration. 
The essential problem arises, of course, from the fact that contaminants 
found in recycled plastic, because of their previous use, could leach out 
of the new containers and into the food. A brief acknowledgment of the 
wide variety of uses that plastic containers find shows the magnitude of 
the concern. Thus, plastic holds everything from food itself including 
milk to chemicals such as herbicides and insecticides that could prove 
toxic to humans and other animals. 
Consumers may exacerbate the problem. After emptying the contents of a 
plastic container, they may reuse it to hold chemicals of an entirely 
different, and perhaps more ominous nature, than the originally held 
ingredients. These may include everything from used motor oil to all types 
of poisons. These containers too, after their initial and subsequent uses 
by the consumer, may enter the recycling stream. Any use of the plastic 
from these containers in recycling must provide absolute assurance that 
whatever such containers may have held will pose no danger to food 
consumed by individuals. 
The United States Food and Drug Administration (FDA) has determined that a 
contaminant on a level below 0.5 parts per billion in ingested food 
presents substantially no risk of harm to humans. Thus, any use of 
recycled plastic in containers must provide assurance that it will not 
cause the exceeding of that level of undesired foreign substances in a 
person's diet. In particular, the FDA requires a demonstration, under 
adverse conditions, of protection against four classes of chemicals; these 
classes include volatile and nonvolatile, polar and non polar organic 
compounds, as well as a heavy-metal salt and a polymer-specific chemical. 
Thus, the intended manner of use of post-consumer recycled ("PCR") plastic 
must show that it will not introduce more than the-indicated amount of 
contaminant into food. 
One particular method of employing recycled resin involves placing a 
barrier layer on the inside of the previously used plastic. Such a barrier 
must prevent the passage of contaminants into a container's interior 
holding a food-like substance, generally an ethyl alcohol solution. One 
test for establishing this barrier capacity involves placing the container 
made of or with the proposed barrier and containing the alcohol solution 
in essentially pure contaminant. Alternatively, the test may involve 
placing the contaminant on the exterior of a container with the barrier 
material. 
The need for a barrier, however, only exists when the contaminant level 
within the recycled plastic exceeds certain maximum levels. Below those 
levels, as suggested in the FDA Points to Consider for the Use of Recycled 
Plastics in Food Packaging: Chemistry Considerations (May, 1992), an 
insufficient amount of contaminant could possibly leach into the 
container's contents to create a health risk. The calculation assumes that 
all of a contaminant in the PCR resin will enter the container's food. In 
the case of polyolefins, that contaminant level currently stands at 48 
parts per billion (ppb.) for a container having a PCR layer 0.020 inch 
thick. A thicker layer will have more contaminant and cause the 
permissible level to proportionately decline. Several layers with PCR 
introduce additive quantities of the contaminant. This has special 
significance since much PCR resin has a majority of polyethylene. 
Polyethylene terepthalate ("PET"), by comparison, may have a residue of 
215 ppb. Between those two sit polystyrene at 180 ppb. and polyvinyl 
chloride at 90 ppb. Decreasing the PCR layer thickness increases the 
allowable contaminant level. Only the thickness of the layers within the 
PCR are considered in this determination. Diluting the PCR with virgin 
resin proportionately increases the permissible contaminant level in the 
unmixed PCR. 
The current recycling process does appear to reduce the concentration of 
some contaminants in previously used resin. However, the present treatment 
of recycled materials does not seem to currently offer the hope of 
reducing the residue level of all contaminant types to below these limits. 
Accordingly, the search continues for barriers that will permit the use, 
and perhaps the required use, of recycled plastic for food containers. 
Yet, the barrier should not prohibitively increase the cost of the 
resulting containers. 
SUMMARY 
Various materials that have experienced substantial use for other purposes 
have provided the very pleasant surprise of acting as barriers to the 
migration of contaminants from recycled plastics into a container's 
interior. Ethyl vinyl alcohol (EVOH) has often acted as a barrier against 
the passage of gaseous or dissolved oxygen through plastic. Polypropylene 
by itself forms containers of improved heat resistance and clarity. 
Fluorinating a polyolefin provides it with a less tacky surface and helps 
prevent the escape of certain volatile organic liquids held in the 
container. However, a substantially continuous film of any of these 
materials either alone or in combination now appears to provide an 
effective barrier against the migration of contaminants into a container's 
interior. 
In general terms, a container has a wall which defines an interior and an 
exterior. Since a large proportion of recycled plastic takes the form of 
polyethylene, at least one layer in the container wall would typically 
include a polymer of that type. 
An effective barrier then requires a substantially continuous film of the 
appropriate material. The film occurs at the portion of the part of the 
wall wherever the layer of PCR occurs. It has a location, at that portion, 
toward the interior of the container from the first, or recycled 
polyethylene polymer, layer. 
Generally, the film should display no discontinuities to provide the best 
barrier. Minor gaps might not prove intolerable, depending upon the 
conditions, so long as the contaminant concentration reaching the 
container's interior remained below the level of unacceptability as 
discussed above. 
Regardless of the exact nature of the barrier, it should have a sufficient 
thickness and capability to prevent the passage of more than one percent 
of the contaminants in the PCR layer into the container's contents in 10 
days. As an alternative guideline, the barrier should prevent the entrance 
from the PCR layer into the container's interior of contaminants exceeding 
20 ppb. of the weight of the container's contents, also over a 10-day 
period. These limits take into consideration the "consumption factor" put 
forth by the FDA as discussed below, to keep the total ingested level 
below 0.5 ppb. of a person's diet. 
Where the continuous film has a composition of polypropylene, the 
exteriorly located layer may take the form of any polyethylene. The 
polypropylene serves most importantly to prevent migration of unacceptable 
quantities of contaminants from the polyethylene into the container's 
interior. It may also, however, serve other purposes such as physical 
protection or guarding against chemical attack from the container's 
contents. Thus, it may possibly find use for lining polyethylene not 
derived from a recycled source. 
EVOH has provided an oxygen barrier in containers made of various types of 
polyolefins. However, no one has previously recognized that it will 
provide an adequate barrier to the passage of contaminants from recycled 
plastic. This gives EVOH a new use which allows concomitantly the reuse of 
plastic in food containers rather than merely non-food applications or 
burying or other disposal. 
Fluorinating a polyethylene provides it with a Teflon-like, nonsticky 
surface with improved resistance to the escape of volatile organic 
liquids. However, where that or another polyethylene layer carries 
contaminants, the fluorinated film acts as a barrier against the 
contaminants' migration into the container. 
The method of making a container utilizing either polypropylene, EVOH, or a 
fluorinated polyolefin as a barrier against contaminants first involves 
composing a resin incorporating post-consumer recycled thermoplastic 
containing polyethylene. Then occurs the molding of the container having a 
wall defining ah interior and an exterior. 
The actual molding includes forming from the resin incorporating the PCR a 
layer of at least part of the wall. In the case of a polypropylene or EVOH 
barrier, a second layer is formed at the part of the wall having the PCR 
resin. The second layer has a substantially continuous film of 
polypropylene or EVOH, as the case may be. This film of the polypropylene 
or the EVOH occurs at the portion of the wall wherever the first layer 
with the PCR resin occurs. The film of the polypropylene or EVOH must have 
a location toward the interior of the container from the first layer with 
the PCR in order to act as a barrier to the migration of possible 
contaminants within the PCR. 
Oftentimes, where the barrier utilizes EVOH, the making of the container 
also involves forming a third layer which places a continuous film of 
polyethylene or polypropylene at the location of the EVOH but toward the 
interior of the container. This provides EVOH with protection against 
moisture which shows a tendency to degrade its capability of blocking the 
passage of gases into the container. An adhesive on either side of the 
EVOH will prevent or at least reduce delamination of the various layers 
from each other. 
The use of a fluorinated polyolefin as a barrier does not necessarily 
involve the formation of a separate identifiable layer of the barrier 
compound. Rather, the requisite film of fluorinated polyolefin proceeds 
through the formation of a continuous film of the fluorinated 
polyethylene. This film should occur at a portion of the part of the wall 
of the container wherever the layer of recycled resin occurs. Naturally, 
it lies towards the interior of the container from the PCR. The formation 
of this film of fluorinated polyethylene typically occurs through the 
direct fluorination of polyethylene already present in the container. This 
requires merely the contacting of the polyethylene with the fluorine gas 
at reactive temperatures. This may specifically occur either during or 
after the molding of the container itself.

DETAILED DESCRIPTION 
The FDA has determined that contaminant concentrations of less than 0.5 
ppb. in the food stream does not cause an appreciable likelihood of harm 
to humans. Incorporating various assumptions including a "consumption 
factor" of 0.33 in the Points to Consider . . . paper alluded to above, 
the FDA has determined the level of contaminants in various types of 
materials used in containers that will not result in exceeding the limit 
for consumption of food held by the container. In the case of polyolefins, 
that level amounts to 48 ppb. for 0.020 in. layer. In other words, if a 
polyolefin contains less than 48 ppb. of contaminant, then the FDA has 
determined that food in contact with that polyolefin as a container wall 
0.020 in. thick will not receive the contaminants in an amount that will 
cause the exceeding of the 0.5 ppb. dietary limit. Decreasing the 
consumption factor proportionately increases the tolerable contaminant 
level. Thus, a consumption factor of 0.10 will give a limit of about 150 
ppb./0.020 in. for the polyolefin. The polyolefin simply has insufficient 
contaminant to leach into the food in an amount that could cause danger to 
humans ingesting that food. Accordingly, if the post-consumer reground 
polyolefin resin had less than 48 ppb. of any deleterious contaminant, 
then it could find direct use in a food container where it would make 
direct contact with the food itself. 
However, assuring that the PCR resin will only contain contaminants below 
this level does not appear feasible. No selection process even appears on 
the horizon that would separate PCR polyolefins with no contaminant above 
that level from those with excessive amounts of unacceptable chemicals. 
Further, no method of reprocessing PCR polyolefin resin has the ability of 
economically reducing all contaminants below the acceptable level. 
Accordingly, the use of PCR resin necessitates the employment of a barrier 
that will prevent the migration of contaminants from the PCR resin of a 
container wall into the food held by that container. 
Polypropylene, EVOH, and fluorinated polyethylene have each shown the 
ability to act as a barrier to the migration of contaminants into a food 
product held in a container. Each has kept contaminants of all types from 
entering food-like materials inside of a plastic bottle in excessive 
quantities. 
Tests actually performed on various materials to determine their 
effectiveness as barriers involved first the construction of 12-ounce 
bottles having wall thicknesses generally in the range of 0.030 to 0.035 
inch. Bottles were formed from high density polyethylene ("HDPE") and 
polypropylene. Multilayered bottles undergoing testing included HDPE with 
an EVOH barrier layer, HDPE with a nylon barrier layer, HDPE with a 
fluorinated inner surface, and HDPE with different polypropylene barriers. 
More specifically, the HDPE and the polypropylene bottles had a uniform 
composition throughout. Fluorinated HDPE, of course, had only a thin, 
possibly monomolecular, layer of fluorination on the interior surface; it 
received this by contacting the polyethylene with fluorine gas at elevated 
temperatures after molding. 
The HDPE/EVOH bottles had a construction of five coextruded layers. These 
included, with the respective target percentages stated in parentheses and 
starting from the exterior: 
HDPE(23.5)/ADH(1.5)/EVOH(3.5)/ADH(1.5)/HDPE(70). A second of series of 
HDPE/EVOH used HDPE(20%)/Regrind(66%)/ADH(1%)/EVOH(2%)/ADH(1%)/HDPE (10%). 
The adhesive ("ADH") took the form of a modified polyethylene sold as 
Tymor by Morton. The HDPE/nylon bottles had the same construction and 
percentages as for first HDPE/EVOH bottles except that the adhesive took 
the form of an ethylene vinyl acetate sold as Plexar by Quantum Chemical 
Corporation, and of course nylon replaced EVOH. 
The multilayered bottles including the polypropylene included first an 
outer layer of polyethylene and an inner, protective layer of random 
polypropylene copolymer with about one percent ethylene content. One 
series of these bottles utilized about 30 percent polypropylene on the 
interior layer while a second series utilized only about ten percent of 
polypropylene to impose a more severe test on the material. A further 
series of tests utilized a layer of polypropylene providing about 30 
percent of the bottle's weight but including a blend of about 25 percent 
of ethylene found in domains. 
The testing employed contaminants in each of the four classes recommended 
by the FDA. Toluene filled the role of a volatile, nonpolar organic 
material as well as a polymer-specific contaminant for the polyolefins. 
Chloroform represented a volatile, polar organic material; methyl 
salicylate filled the role of a nonvolatile, polar material; and 10 
percent lindane in toluene represented the nonvolatile, non polar organic 
material. Aside from the lindane as indicated above, the other 
contaminants found use at substantially full strength. 
The bottles with the ethyl alcohol solution underwent exposure to toluene, 
chloroform, and the solution of lindane in toluene by dipping them in the 
various liquids. The viscosity of the methyl salicylate required wiping it 
onto the bottles' exteriors. All of the bottles had an eight percent ethyl 
alcohol solution inside. 
After exposure, the bottles remained capped and stored for periods of one, 
three, and ten days at 25.degree. C. and 49.degree. C. The FDA has 
suggested these temperatures since both lie above those at which the 
containers would actually be used. Thus, the 25.degree. test applies to 
containers for food that would remain refrigerated during storage. This 
would include orange juice and milk for example. The 49.degree. test 
applies to containers holding food at room temperature. This would include 
cranberry juice. The higher temperatures supposedly induce greater 
migration than would occur under the normal and appropriate conditions 
that the containers would face. 
After these residence times, the alcohol solution in the various bottles 
underwent analysis to determine the contaminant concentrations in them. 
The results showed preliminarily that, in effect, the lindane did not 
migrate through any of the polymers. Accordingly, the lindane tests did 
not proceed under all of the conditions of the other contaminants. 
Results of a substantially different nature occurred for the other 
contaminants. Thus, methyl salicylate, toluene, and chloroform migrated 
readily through the polyethylene bottles into the alcohol solution. 
Virtually no migration occurred through the pure polypropylene except for 
a minor amount of chloroform after 10 days' storage and at high 
contamination levels on the containers+ exterior. Appreciable migration 
occurred for the contaminants (excepting lindane) through the nylon 
barrier especially after 10 days. 
The multilayered polypropylene and EVOH bottles and the fluorinated bottles 
acted as very substantial barriers to the migration of the other 
contaminants in addition to lindane. Although they allowed the passage of 
some chloroform, they blocked the vast proportion of it. Additionally, the 
cleaning process similar to that used for recycled plastic appears to have 
a very substantial effect in removing isopropanol, a volatile polar 
organic compound. It probably will have the same effect on chloroform 
which falls in the same class of compounds. Moreover, the elevated 
temperatures needed for molding, based on the same reasoning will likely 
drive off additional chloroform. Further, the plastic appears to only 
absorb relatively minimal amounts of this class of compounds. Thus, 
CHCl.sub.3 displays some ability to migrate even through these barriers; 
in reality however, because of the above, it should pose very little risk. 
The bottles with the thinner (0.001 inch) layer of EVOH permitted the 
passage of somewhat more methyl salicylate over 10 days than did the 
thicker layer of EVOH. The 25 percent blend of polyethylene within the 
polypropylene permitted the passage of very minor amounts of the 
contaminants. The tests had exposed the bottles to extremely high levels 
of contaminants. Yet, the polypropylene, whether in layers or forming 
solid bottles, as well as the EVOH and fluorinated bottles, effectively 
blocked very large amounts of contaminants from reaching the interior of 
the containers they protected. This polypropylene appeared in a uniform 
copolymer form or in blends. 
Accordingly, the use of polypropylene, EVOH, and fluorinated polyethylene 
as a barrier against contaminants from PCR resin in a container would 
appear propitious. A simple type of container making use of a 
polypropylene appears generally at 11 in FIG. 1. The container 11 includes 
the bottom 12, the side 13, and the neck 14 at the top. 
As seen in FIGS. 1 and 2, the construction of the container 11 utilizes the 
thicker exterior layer 16 covered by the thinner barrier layer 17 on the 
inside. The post-consumer recycled resin appears in the outer layer 16. 
Typically, the PCR resin is composed primarily, if not exclusively, of 
polyethylene, most often high density polyethylene. The inner, or barrier, 
layer 17 includes the polypropylene. 
A container construction more typical than that in FIGS. 1 and 2 appears in 
FIG. 3. The inner layer 20 again has a composition of polypropylene. The 
outer layer 21 takes the form of the PCR. The middle layer 22, in this 
construction, includes reground trim scrap. This comes from prior bottles, 
flash, and the like which can include portions of all three layers from 
prior moldings. 
As an alternate construction the middle layer 22 may contain the PCR. The 
outer layer 21 may then include virgin resin with a pigment. Again, the 
inner layer 20 has the polypropylene. 
Whether having the structure of FIGS. 2 or 3, the container has the inner 
layer 17 or 20, respectively, of polypropylene. At the very minimum, the 
layer of polypropylene 17 or 20 must provide a substantially continuous 
film toward the interior of the bottle. Specifically, it must lie more 
towards the inside of the bottle than does the PCR layer 16 or 21 and 22. 
This will keep contaminants from the PCR layers from entering and 
contaminating the food in the interior of the container. Typically, the 
polypropylene layer 17 or 20 should provide a thoroughly continuous film. 
This gives the best protection. 
Extrapolating from the above, a polypropylene layer constituting even as 
little as one percent of the container's weight may serve as an adequate 
barrier. Where the polypropylene amounts to 10 percent of the container's 
weight, substantial assurance results for even higher levels of 
contaminants. 
In general, the barrier should lie towards the interior of the container 
from virtually any layer containing PCR. This holds true, of course, 
whether the barrier takes the form of polypropylene, EVOH, or the 
fluorinated polyethylene. This configuration permits the barrier to stand 
between the contaminants in the PCR and the contents of the container. As 
discussed below, however, this configuration does not require the location 
of the barrier at the very interior of the container wall. In fact, the 
wall may include additional layers lying on the inside of the barrier. 
With regards to EVOH, in particular, a layer of polyolefin often appears 
useful in order to prevent deterioration of the gas-barrier properties of 
this material. 
As discussed above, a polyolefin having less than 48 ppb. of contaminants, 
according to the FDA, does not require a barrier of any type. This results 
from the conclusion that the amount of contaminant that might enter the 
food stream from such material would pose no hazard to humans. If the 
container wall only included materials having contaminants having less 
than 48 ppb., it would require no barrier whatsoever. 
Moreover, a container might include a layer with more than 48 ppb. and thus 
have a barrier between this PCR and the interior of a container. However, 
including between the barrier and the container's interior a further layer 
of a resin having contaminants but below the 48 ppb. level should pose no 
hazard either. The barrier would prevent the migration of the undesired 
chemicals from the highly contaminated PCR while the low level of such 
contaminants lying toward the interior of the barrier by themselves would 
give rise to no concern. 
Further FIG. 1 shows the polypropylene layer 17 covering the entire 
interior of the container 11. That, of course, follows since the PCR layer 
16 appears over the entire exterior of the container 11. An alternate 
construction might place the PCR resin over only a portion of the 
container, such as the bottom 12 and only the lower portion of the side 
wall 13. In this instance, having polypropylene cover similarly the 
interior of the bottom and also the lower portion of the side wall for at 
least the portion including the PCR might suffice to provide the required 
barrier against contaminants. In other words, where the PCR does not 
appear over the entire container 11, the polypropylene may itself need not 
cover the entire container 11 in order to provide an adequate barrier 
against the contaminants. 
Furthermore, the inner layers 17 and 20 will most likely not have 
absolutely pure polypropylene. It typically includes some polyethylene or 
other comonomers. And, it may also take the form of a blend which has 
domains of other molecules, especially polyethylene as discussed in U.K. 
patent specification 1,346,234 to the Mitsui Petrochemicals Inds., Ltd. 
Naturally, the amount and type of contaminants will have an effect upon the 
thickness required of the barrier layer to provide the effective 
continuous film of polypropylene that will adequately protect against the 
contaminants from the PCR. The method of determining the exact thickness 
required should not pose any particular difficulty. Containers 
incorporating layers of different thicknesses of the type of polypropylene 
desired can undergo the types of testing described above to determine the 
amount of contaminants that could pass through. This would show the 
required thickness for preventing the passage of unacceptable layers of 
contaminants. 
Typically, the polypropylene layer 17 or 20 will constitute at least about 
one percent of the weight of the entire container 11. It may even have a 
thickness that will provide 10 percent or more of the container's weight. 
To prove practicable, the container should incorporate at least about 15 
percent of its weight in PCR resin. Some states, in fact, have under 
consideration a requirement that the container include at least 25 percent 
by weight PCR. That, of course, would fall in the outer layer 16 in FIG. 
2. The layer 16 could also include virgin polyethylene or other polymers 
to constitute the remaining amount of the container wall. 
In FIG. 3, the PCR appears in the two outer layers 21 and 22. These will 
hold the required quantity of PCR. If the PCR amounts to 25 percent, then 
the outer layer, for example, could take the form of only recycled 
polyethylene and constitute 15 to 20 percent by weight of the entire 
container. The inner layer 22 would then provide the remaining 5 to 10 
percent of the desired recycled polyethylene. It could also include 
reground polypropylene and virgin resin. 
When the inner layer 20 constitutes about 30 percent by weight of the 
container and the exterior layer 21 amounts to 15 to 20 percent, then the 
middle layer 22 will amount to about 50 to 55 percent by weight of the 
container. In general, of course, the desired amount of PCR resin as well 
as the available trim scrap will determine the amount of the virgin 
plastic introduced into the outer layer 16 of FIG. 2 or the middle layer 
22 of FIG. 3. Naturally, the amount of PCR resin may increase and form 
substantially all of the container 11. That, of course, would necessitate 
a barrier layer 17 or 20 of sufficient thickness to prevent the migration 
of an unacceptable level of the contaminants from this type of outer 
layer. 
In the structure shown in FIG. 2, the outer layer 16 may, in fact, include 
no PCR resin. In other words, it may simply only have virgin resin 
possibly with ground trim scrap. In this fashion, the polypropylene 17 may 
provide protection against the bottle's contents crazing the surface of 
the outer layer 16. It may also provide a barrier where the bottle makes 
contact with contaminants from the exterior which may travel through the 
outer layer 16 similar to the tests discussed above. 
FIG. 4 gives a cross-sectional view of a simplified structure using EVOH as 
a barrier to contaminants from PCR. There, the inner layer 25 is the EVOH 
while the outer layer 26 includes the PCR. It may have only the PCR or it 
may also incorporate virgin resin and ground trim scrap. Again, to prove 
practical, it should have at least 15 percent and most likely 25 percent 
by weight of the entire container in the form of PCR resin. 
Typically, EVOH does not sit on either the interior or exterior surface of 
a container. This results from the fact that moisture can degrade its 
ability to act as a gas barrier. Accordingly, FIG. 5 shows a wall 
structure similar to FIG. 4 except that it has the layer 29 of polyolefin 
lying on the inside of and protecting the EVOH layer 30. This keeps the 
moisture from the interior of the container from attacking the EVOH. The 
polyolefin may take the form of either polyethylene or polypropylene. The 
former probably represents the preferred choice since it costs less. 
Either may constitute around 10 percent of the container's weight. The 
extra layer 31 again contains the PCR resin. 
Plastic attached directly to EVOH displays a tendency to delaminate. 
Accordingly, the wall structure of FIG. 6 provides an adhesive, generally 
in the form of a modified polyethylene, as the two layers 33 and 34 
surrounding the EVOH 35. Using a different polyolefin as the interior 
layer 36 would indicate choosing a specific adhesive for the layer 34. 
Again a layer of polyolefin 36 lies toward the inside of the EVOH 35 to 
protect it (as well as its adhesive 34) from the contents of the 
container's interior. The PCR resin layer 37 lies to the outside and 
attaches to the outer layer of adhesive 33. 
The wall structure shown in FIG. 7 differs from that in FIG. 6 by including 
the layer of ground trim scrap 41. This would include components from all 
of the other layers and prior moldings. It sits between the PCR resin 42 
and the outer layer of adhesive 43 which attaches it to the EVOH 44. The 
inner layer of the adhesive 45 then attaches the EVOH to the layer of 
polyethylene 46. A discussion of the general forms of adhesive that may 
find use as the layers 33 and 34 in FIG. 6 and 43 and 45 in FIG. 7 appears 
in U.S. Pat. Nos. 4,182,457 to M. Varnada et al. and 4,254,169 to G. O. 
Schroeder. Typically, the bottle will include about two to four percent by 
weight of the EVOH; more generally, it should fall within the range of 
around 1.5 to 13 percent. Each of the adhesive layers will constitute 
about one to two percent of the container's weight. 
Typically, the inner layer 29, 36, and 46 of FIGS. 5, 6, and 7, 
respectively, provide about 30 percent of the container's weight. As 
suggested above, the polyolefin would typically appear as polyethylene. 
The PCR resin in the layer 26 of FIG. 4, the layer 31 of FIG. 5, the layer 
37 of FIG. 6, and the layers 41 and 42 of FIG. 7 provide the requisite 
amount of recycled resin. Minimally, this amounts to about 15 percent, but 
may even rise to 25 percent or more. These layers may include virgin resin 
and, in the intermediate layer 41 of FIG. 7, ground scrap. 
In the structure shown in FIG. 7, the intermediate layer 41 may constitute 
about 30 to 35 percent of the weight of the container and, typically, 
include approximately five to ten percent virgin resin, 20 to 30 percent 
reground scrap. The outer layer 42 provides around 30 to 35 percent of the 
bottle's weight and will contain approximately 15 to 20 percent of the 
bottle's weight of PCR and 15 to 20 percent of the bottle's weight of 
regrind. This, of course, permits the inner layers 41, and 43 to 46 to 
protect the container's contents from contaminants. For a colored 
container, the outer layer 42 may contain pigment, reground and virgin 
resin; The PCR will then appear in the layer 41. 
FIG. 8 shows a portion of a container wall having the layer 51 of plastic 
containing post-consumer recycled resin. The fluorinated polyethylene film 
52 has a location toward the interior of the container from the 
PCR-containing layer 51. FIG. 8 diagrams the film 52 as entirely separate 
from the layer 51. In fact, of course, the film 52 may include a surface 
portion of the layer 51 which has undergone fluorination to create the 
continuous film of fluorinated polyethylene. The container wall in FIG. 9 
similarly has the layer 55 of PCR-containing resin. The film 56 of 
fluorinated polyethylene again protects against migration of contaminants 
into the container's interior. However, the additional layer 57 may 
include trim scrap from prior moldings or even virgin resin such as 
polyethylene. In fact, in this instance the film 56 results from the 
fluorination of the polyethylene in the intermediate layer 57 rather than 
the PCR layer 55. As a particular example, the intermediate layer 57 may 
represent approximately 20 percent of the container's weight while the 
outer layer 55 provides the remaining 80 percent. As suggested by these 
numbers, the fluorinated film 56 constitutes a minuscule portion of the 
container's weight. 
The preparation of the PCR for the containers diagrammed in the figures 
typically involves the comminuting or otherwise reducing the size of the 
pieces of the previously used plastic. This puts the plastic into small, 
useful pellets or sections in which it may find further use in the making 
of new containers. 
After the size reduction of the plastic, it typically will undergo some 
form of washing. This has the effect of removing a substantial portion of 
the contaminants especially from the superficial areas of the plastic. 
After drying, the PCR goes through an extruder and filter and departs as 
pellets. 
Then, the PCR may become mixed with other resin. The additional material 
may take the form of virgin plastic or reground trim scrap or both. This 
mixing with other plastic further dilutes the contaminants. 
The plastic, whether composed entirely of PCR or a mixture of PCR with 
other resin, has become ready for molding by any one of a number of 
processes. All of these, of course, involve subjecting the plastic resin, 
including specifically the PCR, to highly elevated temperatures to melt 
them. These temperatures and the concomitant melting of the plastic may 
drive off some contaminants originally present in the PCR. Volatile 
organic compounds, such as chloroform, would likely display a substantial 
vulnerability to their partial removal in this fashion. 
The step of heating and subsequent molding may even reduce some of the 
contaminants to a level where they might not in fact need a barrier. But 
in any event, reducing the amount of contaminant in the container whether 
through the washing or the heating and molding processes reduces the 
standards that a barrier must meet. It need only prevent the migration of 
that amount of contaminant which otherwise would, if contained in the 
actual edible material, exceed the FDA limits discussed above. 
Any of the available molding techniques, of course, can find use to make 
containers from the melted resin. For a single-layer container with the 
fluorinated interior surface, this involves merely the injection or blow 
molding of the resin. This step could produce the container directly. 
Alternatively, it could create an intermediate form from which subsequent 
steps would create the desired container. Thus, extrusion and injection 
molding can both create a parison. The parison, in turn, can undergo blow 
molding to create the final container. 
Additionally, extrusion may find use to create sheets of the plastic. These 
sheets can undergo thermoforming, such as vacuum forming, to provide the 
container. 
Coextrusion will form sheets or parisons in which the different layers have 
been extruded simultaneously. Alternatively, monolayer thin sheets, or 
films, may emanate from the extruder. Placing these together can produce 
flexible plastic packaging utilizing PCR with a protective barrier. 
In any event, the creation of the containers with the fluorinated barrier 
then involves contacting the layer of polyethylene 51 with fluorine gas. 
This could occur anywhere during the actual molding of the container. 
Thus, the gas used during extrusion molding to form the parison may 
include fluorine gas. Or, the pressure for blow molding the parison into 
the final container may provide the fluorine. Effectuating the 
fluorination in this manner has the advantage of contacting the 
polyethylene layer 51 with the fluorine at the elevated temperatures of 
the molten plastic. These elevated temperatures provide conditions of high 
reactivity for the fluorine in contact with the polyethylene. Lower 
temperatures may suffice although that may require longer reaction times 
or higher fluorine concentrations in the gas mixtures. 
Producing the multilayer container of FIG. 9 proceeds in a very similar 
fashion to the production of the single-layer container of FIG. 8. This, 
however, would of course require coinjection or coextrusion of the 
multiple layers 55 and 57. This again could create either an intermediate 
parison or the final container. In the former case, further molding would 
provide the final container. Again, the fluorination to create the 
protective film 56 can occur during any of the stages of molding or 
subsequently. 
The containers of FIGS. 1 to 7 all have multiple layers of plastic. This 
typically involves the coextrusion or coinjection molding of an article 
from the original molten resins. Again, this first step may provide either 
the final container or an intermediate article. In the latter case, blow 
molding or thermoforming will provide the final container.