Abstrict Film structures, packages and methods of making the same are provided
wherein the film structures have a desiccant material incorporated
into a sealant layer of the film structures and further wherein
the sealant layer of the film structures comprise a material for
making a peelable seal when the film structures are heat sealed
to other film structures. The film structure is utilized for a package
to hold a product that may be sensitive to the presence of moisture.
The product may preferably be pharmaceutical or nutriceutical products,
although any moisture-sensitive product is contemplated by the present
invention.
Claims We claim:
1. A first film structure comprising: a plurality of layers wherein
a first layer comprises a desiccant material blended therein and
further wherein said first layer comprises a material for making
a peelable seal when the first layer is heat-sealed to a second
film structure.
2. The first film structure of claim 1 wherein said desiccant material
is a chemical desiccant material.
3. The flexible film structure of claim 1 wherein said desiccant
material is selected from the group consisting of calcium oxide,
magnesium oxide, barium oxide, barium hydroxide, strontium oxide,
aluminum oxide, partially hydrated aluminum oxide, magnesium sulfate,
sodium phosphate di-basic, ammonium chloride, potassium carbonate,
potassium aluminum disulfate, magnesium chloride, diammonium sulfate,
sodium nitrate, calcium chloride, calcium sulfate, sodium chloride,
potassium bromide, molecular sieves, clays and blends of these materials.
4. The first film structure of claim 1 wherein said first film
structure further comprises a barrier layer wherein said barrier
layer comprises a material selected from the group consisting of
metal foil, nylon, high density polyethylene, oriented or cast polypropylene,
metallized oriented polypropylene, oriented polyester and high density
fluorocarbon polymer.
5. The first film structure of claim 4 further comprising a first
tie layer of a polymeric material disposed between said barrier
layer and said sealant layer.
6. The flexible film structure of claim 5 wherein said first tie
layer of polymeric material comprises ethylene acrylic acid copolymer.
7. The flexible film structure of claim 1 further comprising: a
second layer of a polymeric material.
8. The flexible film structure of claim 7 wherein said second layer
is an outer layer of the first film structure and further comprises
a polymeric material selected from the group consisting of polyethylene
terephthalate, oriented polypropylene, polyethylene, nylon, foil,
metallized substrates and high density fluorocarbon polymer.
9. The first film structure of claim 7 wherein said first layer
is an inner heat sealant layer and further wherein said first flexible
film structure comprises a barrier layer disposed between the outer
layer and the inner heat sealant layer and further comprising a
second tie layer disposed between said outer layer and said barrier
layer.
10. The first film structure of claim 9 further comprising: a first
tie layer disposed between said inner heat sealant layer and said
barrier layer.
11. The first film structure of claim 10 further comprising: a
second tie layer disposed between said outer layer and said barrier
layer.
12. The first film structure of claim 10 wherein said first and
second tie layers each comprise ethylene acrylic acid copolymer.
13. A package comprising: a first film structure wherein said first
film structure comprises a plurality of layers wherein a first layer
comprises a first desiccant material; a second film structure heat
sealed to said first film structure; and a space inside the package
for a moisture-sensitive product, wherein said package further comprises
a material for making a peelable seal between said first film structure
and said second film structure when said first film structure is
heat-sealed to said second film structure.
14. The package of claim 13 wherein said desiccant material is
a chemical desiccant material.
15. The package of claim 13 wherein said desiccant material is
selected from the group consisting of calcium oxide, magnesium oxide,
barium oxide, barium hydroxide, strontium oxide, aluminum oxide,
partially hydrated aluminum oxide, magnesium sulfate, sodium phosphate
di-basic, ammonium chloride, potassium carbonate, potassium aluminum
disulfate, magnesium chloride, diammonium sulfate, sodium nitrate,
calcium chloride, calcium sulfate, sodium chloride, potassium bromide,
molecular sieves, clays and blends of these materials.
16. The package of claim 13 wherein said second film structure
comprises a heat sealable layer for heat sealing to the first layer
of said first flexible film structure.
17. The package of claim 13 wherein said second film structure
comprises a plurality of layers wherein a first layer of said second
film structure comprises a second desiccant material wherein said
first layer of said first film structure and said first film layer
of said second film structure are heat-sealed together.
18. The package of claim 13 wherein said first film structure comprises:
an outer layer of polyethylene terephthalate; a core layer of a
barrier material forming a barrier layer; a first tie layer disposed
between said first layer and said barrier layer; and a second tie
layer disposed between said barrier layer and said outer layer.
19. The package of claim 16 wherein said second film structure
comprises a second layer of a polymeric material.
20. The package of claim 19 wherein said second film structure
is thermoformed to form said space for said second moisture-sensitive
product.
21. The package of claim 13 wherein said first film layer of said
first film structure comprises said material for making the peelable
seal between said first film structure and said second film structure
when said first film structure is heat-sealed to said second film
structure.
22. The package of claim 13 wherein said second film structure
comprises said material for making the peelable seal between said
first film structure and said second film structure when said first
film structure is heat-sealed to said second film structure.
23. A method of making a first film structure comprising the steps
of: extruding a first film layer comprising a blend of a polymeric
material, a desiccant material, and a material for making a peelable
seal when the first film structure is heat-sealed to a second film
structure; and laminating said film layer to a second film layer.
24. The method of claim 23 wherein said first film layer is extruded
via a blown film extrusion process.
25. The method of claim 23 wherein said first film layer is extruded
via a cast extrusion process.
26. The method of claim 23 wherein said first film layer is adhesively
laminated to said second film layer.
27. The method of claim 23 wherein said first film layer is extrusion
laminated to said second film layer.
28. The method of claim 23 further comprising the step of: coextruding
a tie layer with said first film layer comprising the blend of the
polymeric material, the desiccant material, and the material for
making a peelable seal when the first film structure is laminated
to a second film structure; laminating said tie layer and said first
film layer to said second film layer.
29. The method of claim 23 wherein said second film layer comprises
a barrier material to form a barrier layer.
30. The method of claim 29 wherein said barrier layer comprises
a material selected from the group consisting of metal foil, nylon,
high density polyethylene, oriented polypropylene, metallized oriented
polypropylene, metallized polyester and high density fluorocarbon
polymer.
31. A package having a space therein for a moisture-sensitive product
made from the first film structure made via the method of claim
23 wherein said first film layer is a heat sealant layer and wherein
said heat sealant layer is heat-sealed to said second film structure.
32. A method of making a flexible film structure, comprising the
step of: extrusion coating a film layer comprising a blend of a
polymeric material, a desiccant material, and a material for making
a peelable seal when the first film structure is laminated to a
second film structure.
33. The method of claim 32 wherein said second film layer is a
moisture barrier layer.
34. The method of claim 33 wherein said moisture barrier layer
comprises a material selected from the group consisting of metal
foil, nylon, high density polyethylene, oriented polypropylene,
metallized oriented polypropylene, metallized polyester and high
density fluorocarbon polymer.
35. The method of claim 32 wherein said first film layer comprising
the blend of the polymeric material, the desiccant material, and
the material for making a peelable seal when the first film structure
is laminated to a second film structure.
36. A package having a space therein for a moisture-sensitive product
made from the film structure made via the method of claim 32 wherein
said first layer is a heat sealant layer and further wherein said
heat sealant layer is heat sealed to a second film structure.
37. A first film structure comprising: a plurality of layers wherein
a first layer comprises a desiccant material blended therein; a
second layer disposed adjacent to said first layer forming an inner
sealant layer; and a peelable film component disposed within said
first or second layer of said film structure.
38. The first film structure of claim 37 wherein said desiccant
material is a chemical desiccant material.
39. The flexible film structure of claim 37 wherein said desiccant
material is selected from the group consisting of calcium oxide,
magnesium oxide, barium oxide, barium hydroxide, strontium oxide,
aluminum oxide, partially hydrated aluminum oxide, magnesium sulfate,
sodium phosphate di-basic, ammonium chloride, potassium carbonate,
potassium aluminum disulfate, magnesium chloride, diammonium sulfate,
sodium nitrate, calcium chloride, calcium sulfate, sodium chloride,
potassium bromide, molecular sieves, clays and blends of these materials.
40. The first film structure of claim 37 wherein said first film
structure further comprises a barrier layer wherein said barrier
layer comprises a material selected from the group consisting of
metal foil, nylon, high density polyethylene, oriented or cast polypropylene,
metallized oriented polypropylene, oriented polyester and high density
fluorocarbon polymer.
Description FIELD OF THE INVENTION
[0001] The present invention relates to a film having a desiccant
material incorporated therein. More specifically, the present invention
relates to a film structure having a desiccant material within a
sealant layer of the film structure wherein said film structure
is utilized in a package for a product that may be sensitive to
the presence of moisture. In addition, the present invention relates
to methods of manufacturing and methods of using the film having
a desiccant material incorporated therein.
BACKGROUND OF THE INVENTION
[0002] It is generally known to utilize plastic packaging to reduce
exposure of products to atmospheric conditions, such as to moisture
or oxygen, which may damage the products. For example, packaging
for foodstuffs is well known, in that moisture and oxygen may cause
the foodstuffs to become spoiled and inedible or otherwise undesirable.
In addition, many products in the medical field, such as pharmaceutical
and nutriceutical products, may also be very sensitive to atmospheric
moisture.
[0003] Typically, moisture-sensitive products may be encased in
thermoplastic material that is relatively impermeable to water molecules.
Specifically, many polymeric materials are utilized as barriers
to moisture transmission. For example, a film of high density polyethylene
(HDPE), or polyvinylidene chloride-methyl acrylate (PVdC-MA) copolymer
may be utilized to restrict the movement of water molecules through
the film. Oriented polypropylene, metallized oriented polypropylene,
or metallized polyester would also be useful as moisture barrier
material. In addition, metal foil is known to prevent the transmission
of oxygen and/or moisture through polymeric packaging having a layer
of metal foil contained therein.
[0004] Although these moisture barrier polymers may be useful in
restricting the movement of moisture into a package, some moisture
molecules can still make their way into the package to deleteriously
affect the product contained therein. In addition, even when barrier
materials are effective at restricting the transmission of water
molecules through a package, certain features of the package may
still allow for the transmission of water molecules. For example,
where a barrier material is incorporated into a central layer of
a film structure and the film structure is sealed to another film
structure having a barrier material as a central layer, the edges
of the package may not be protected by the barrier layers. This
may allow moisture to make its way into a package along the edges
of a heat sealed package.
[0005] One solution to maintaining a particularly low or virtually
nonexistent level of moisture within a package is to incorporate
sachets of desiccant material into the internal space of the package
to remove the moisture from the headspace of the package. A sachet
may effectively maintain a very low level of moisture in internal
spaces of packages, but may have difficulty maintaining the same
consistent moisture levels after the package has been opened and
a product has been removed. For example, a typical package of moisture-sensitive
products may contain a plurality of the products. A sachet of desiccant
material incorporated into the package may only guarantee that moisture
level of the package is maintained at a constant or minimal moisture
level until the package is opened and the first product is thereby
removed. The remaining products will be instantly exposed to atmospheric
moisture when the seal of the package is broken. Although the sachet
may remove some moisture from the headspace of the package after
the package is opened, the remaining moisture-sensitive products,
having already been exposed to moisture, may already be damaged.
This may be especially true in bulk packaged materials where sachets
are most often used. Desiccant materials are typically incorporated
into liddings of jars or in sachets of multi-unit packages.
[0006] In addition, sachets of desiccant material may become saturated
with atmospheric moisture relatively quickly thereby decreasing
or eliminating their effectiveness. Moisture-sensitive products,
therefore, stand a greater chance of being damaged by moisture in
this case.
[0007] Moreover, the desiccant material contained in the sachets
is typically in powder or granular form and may leak or otherwise
spill from the sachets thereby contaminating the product or products
contained within the package. For example, if the desiccant material
contacts a food, pharmaceutical or nutriceutical product or medical
device, the food, pharmaceutical or nutriceutical product or medical
device may become contaminated with the desiccant material, which
may be damaging to the health of an individual that consumes the
food product or uses the medical device.
[0008] Additionally, although desiccant material is generally known
to reduce the moisture content within a package, typical desiccant
materials are "physical" desiccant materials, such as
molecular sieves, that bind water molecules within pore spaces of
a material. Typically, physical desiccant materials absorb water
at all humidity levels, but will cease to absorb water when interstices
of the physical desiccant material are filled. Therefore, physical
desiccant materials may be ineffective at high humidity levels.
[0009] An additional type of desiccant material may be hydrate
forming agents such as salts. Typical salts that may be utilized
as desiccant material are magnesium sulfate, sodium phosphate di-basic,
ammonium chloride, potassium carbonate, potassium aluminum disulfate,
magnesium chloride, diammonium sulfate, sodium nitrate, calcium
chloride, and calcium sulfate, although many others are known as
well. Typically, the drying capacity is greatly influenced by the
relative humidity within a package. Generally, no water is taken
up by the hydrate-forming agent until the relative humidity reaches
a value at which the first hydrate forms. In the case of calcium
chloride, for example, the first hydrate occurs at less than about
two percent relative humidity (R.H.). Water is then taken up by
the hydrate forming salt until the first hydrate is completely formed
by the salt. No further water is taken up by the salt until the
relative humidity reaches a second level where the second hydrate
forms. This process continues through as many hydrates as the agent
forms at which point the substance begins to dissolve and a saturated
solution is formed. The saturated solution will then continue to
take up water.
[0010] Although these salts may be effective at removing water
molecules from a quantity of gas that may be contained within the
headspace of a package, since the salt only binds the water molecules
within the salt, the water molecules may easily escape back into
the package. This is known as breathing, and may cause deliquescence
(water droplets and liquidization) inside the package. Typically,
this can happen if the salt becomes saturated and if the temperature
of the package increases, or if the pressure of the package decreases,
which may occur during shipment or storage of the package.
[0011] In addition, salts may not allow moisture levels within
a package to fall to a level that is necessary to protect the moisture-sensitive
product that may be contained within the package. Typically, since
salts have different levels of hydration, humidity levels may remain
at certain level without decreasing until the level of hydration
changes.
[0012] However, these salts may be utilized to maintain certain
humidity levels within the headspace of a package. For example,
certain products may require that a certain level of moisture or
humidity be maintained within the package headspace. Headspace humidity
control for products can be manipulated by incorporation of the
appropriate hydrate forming agents.
[0013] Desiccant materials may also be used that form no hydrates,
such as common salt (NaCl) or potassium bromide (KBr). For example,
common salt will absorb no water at a relative humidity below about
75 percent. When 75 percent relative humidity is reached, a saturated
solution is formed which continues to take up water.
[0014] The present invention may utilize chemical desiccant technology,
which is more preferable because the moisture level within a package
may be maintained at an extremely low level. Chemical desiccant
materials chemically react with water molecules to form a new product,
wherein the water molecules are chemically incorporated into the
new product. For example, calcium oxide binds water in the following
reaction:
CaO+H.sub.2O.fwdarw.Ca(OH).sub.2
[0015] Because the reaction noted above requires very high energy
levels to reverse, it is, for all practical purposes, irreversible.
Chemical desiccant materials typically absorb water at all humidity
levels, and will continue to take up water at high relative humidity
levels. These chemical desiccant materials, therefore, may reduce
levels of moisture within the package headspace to zero or near
zero, which is often desired to maintain maximum dryness of the
product.
[0016] An example of a moisture-sensitive product that would benefit
from the present invention are medical diagnostic testing equipment,
such as diagnostic test strips. Medical diagnostic test strips are
typically used to test for the presence of particular compounds
in a biological fluid, such as blood or urine. For example, diagnostic
test strips may detect the presence of narcotics or other substances.
[0017] A diagnostic test strip is typically dipped into a sample
of the biological fluid and if the individual has traces of narcotics
in the sample of the biological fluid then the diagnostic test strip
may change colors to indicate the presence of the narcotics.
[0018] In addition, diagnostic test strips may be useful to detect
particular levels of naturally occurring compounds that may be present
within biological fluids. For example, high levels of protein in
blood and/or urine may indicate a disease state. Diagnostic strips
are useful to test not only for protein levels, but a plurality
of other indicators for levels of various disease indicators. Diagnostic
strips may also be utilized to detect certain biological conditions,
such as pregnancy.
[0019] Diagnostic strips, like the ones described above, are typically
extremely sensitive to moisture, and must be removed from atmospheric
conditions in order to work properly. In the medical field, it is
extremely important to get accurate readings using diagnostic testing
strips. An inaccurate reading may make it difficult to diagnose
a particular disease state, or may make a doctor misdiagnose a particular
disease-state entirely. In addition, an inaccurate reading may jeopardize
an individual that may test positive for a particular narcotic,
especially if the positive result is a false reading. Therefore,
it is of utmost importance that diagnostic strips be as accurate
as possible.
[0020] Therefore, diagnostic test strips are typically sealed away
from atmospheric conditions. For example, diagnostic test strips
are typically wrapped or otherwise contained within a material that
is impervious to moisture and oxygen that may cause damage to the
diagnostic test strips. A thick plastic or glass plastic package,
jar, vial or other container is typically used to house diagnostic
test strips prior to use. In addition, sachets of desiccant material
are typically incorporated into packaging for diagnostic test strips.
However, these packages suffer from the problems as detailed above.
[0021] Moreover, other examples of moisture-sensitive products
that would benefit from the present invention are pharmaceutical
and/or nutriceutical products, such as pills, tablets, and other
like pharmaceutical or nutriceutical products, that may be contained
within a bottle, or may be individually packaged in individual cavities
that have been thermoformed or otherwise disposed within a sheet
of packaging materials. For example, the pills, tablets or other
pharmaceutical or nutriceutical products may be contained within
multi-unit packages, wherein a rigid or semi-rigid base structure
having multiple cavities contains a plurality of pills, tablets,
or other pharmaceutical or nutriceutical products. A film or sheet
of a multilayer film structure may then be disposed as lidstock
over the rigid or semi-rigid base structure to seal the cells containing
the pills, tablets or other pharmaceutical or nutriceutical delivery
systems. Alternatively, individual cavities for pharmaceutical or
nutriceutical pills or tablets may be formed by heat-sealing two
flexible films together completely around one or more pharmaceutical
or nutriceutical pills or tablets.
[0022] Other examples of typical packages or products that would
benefit from desiccant material are other medical kits, such as
home pregnancy test kits and medical instruments. In addition, other
products include electrostatic shielding packaging for electronic
parts, such as printer cartridges, circuit boards, televisions,
DVDs, printers, modems, personal computers, and telecommunications
equipment, etc. Further, other packaging that would benefit from
desiccant material is packaging for foods, such as cheese, peanuts,
coffee, tea, crackers, spices, flour, bread, etc. In addition, other
products that would benefit from desiccant material incorporated
into the packaging are shoes, boots, film products and cameras,
and products that may be shipped by sea, such as high-value wood
like mahogany that would be damaged if exposed to ambient humidity
typically found in cargo ships.
[0023] A need, therefore, exists for polymeric plastic packaging
that may be used in packaging to preserve products that may be sensitive
to atmospheric moisture. The packaging may comprise films having
a desiccant material incorporated directly into a sealant layer
of the film. In addition, films are needed that effectively control
the level of moisture within packaging without using sachets or
desiccant beads that may become ineffective over time, or that may
contaminate products contained within the packaging. Moreover, films,
methods of use and manufacture are needed to overcome the additional
disadvantages as noted above with respect to sachets, beads or physical
desiccants.
SUMMARY OF THE INVENTION
[0024] The present invention relates to multilayer plastic polymeric
flexible packaging films having a desiccant material incorporated
within a layer of the film. More specifically, the present invention
relates to a polymeric flexible film having a desiccant material
incorporated within a layer of the film that is utilized as a package
for a product that may be sensitive to the presence of moisture.
In addition, the present invention relates to methods of manufacturing
and using the polymeric film having a desiccant material incorporated
therein.
[0025] It is, therefore, an advantage of the present invention,
to provide a polymeric plastic packaging film having a desiccant
material incorporated therein for packages that may contain moisture
sensitive products. These products may be, for example, foodstuffs,
pharmaceutical and/or nutriceutical products and/or other products
that may suffer from the deleterious effects of moisture. Specifically,
pharmaceutical and/or nutriceutical products that are useful in
healthcare may be packaged using a film having a desiccant material
contained within a layer of the film to maintain the utility of
the pharmaceutical or nutriceutical products. The desiccant material
is utilized to control the moisture level within a package made
by the film of the present invention.
[0026] In addition, it is an advantage of the present invention
to provide a film having a desiccant material incorporated therein
that would eliminate the need to incorporate into high cost and
marginally effective sachets or beads of desiccant material that
can contaminate products contained within packages if the sachets
accidentally release the desiccant material into the package. Moreover,
sachets or beads are typically higher in cost and may be relatively
unsightly. Further, they may take up space within a package that
could otherwise be used for product. If the desiccant material within
the sachets or beads are ingested, it may become a health hazard.
By the present invention, the desiccant material is incorporated
directly into the packaging film in a rigid solid state in the packaging
film substrate.
[0027] Moreover, it is an advantage of the present invention to
provide a film wherein the desiccant material is incorporated into
the sealant layer of the film and wherein the film is easily extruded.
In addition, many different types of desiccant materials may be
utilized, thereby allowing for particular relative humidity levels
within the packages.
[0028] The present invention further reduces packaging costs by
allowing for the use of thinner and, therefore, less expensive barrier
materials, such as aluminum foil. For example, many flexible foil
packages made using films of the present invention can have barrier
layers having thicknesses that may be reduced by about 50% or more.
Moisture can enter a package through a film structure where two
film structures are heat-sealed together. The present invention
reduces the moisture absorption by blocking this entry point.
[0029] In addition, it is an advantage of the present invention
to provide a film structure, and a package made therefrom, comprising
a sealant film having a desiccant material and a peelable seal material
that allows the film structure to be easily peeled from another
film structure when the film structure is heat sealed to the other
film structure. This allows moisture-sensitive products to be contained
within a package and be protected from moisture while being easily
openable.
[0030] Additional features and advantages of the present invention
are described in, and will be apparent from, the detailed description
of the presently preferred embodiments and from the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 illustrates a cross-section of a film of the present
invention comprising a desiccant material incorporated therein in
an embodiment of the present invention.
[0032] FIG. 2 illustrates a cross-sectional view of a film structure
having a film layer comprising a desiccant material incorporated
therein in another embodiment of the present invention.
[0033] FIG. 3 illustrates a perspective view of a package made
by the film structure in an alternate embodiment of the present
invention.
[0034] FIG. 4 illustrates a cross-sectional view of the package
along line IV-IV, in the alternate embodiment of the present invention.
[0035] FIG. 5 illustrates a perspective view of an alternate package
comprising a desiccant sealant film of the present invention.
[0036] FIG. 6 illustrates a cross-sectional view of the package
of FIG. 5 of the present invention along line VI-VI.
[0037] FIG. 7 illustrates a perspective view of an alternate package
comprising a desiccant sealant film of the present invention.
[0038] FIG. 8 illustrates a cross-sectional view of the package
of FIG. 7 of the present invention along line VIII-VIII.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0039] The present invention relates to films, film structures,
packages and methods of using and/or manufacturing the films, film
structures and packages of the present invention. Specifically,
the films comprise a desiccant material incorporated into the films
as an integrated component. More specifically, the desiccant material
is contained within a heat sealant layer of a film structure. The
film structure may be utilized to produce a package for a moisture-sensitive
product wherein said package has a first film structure in face-to-face
contact with a second film structure and wherein said film structures
are heat sealed together around the edges of the package while the
product is contained therein. Although many types of moisture-sensitive
products may be contained within the packages made from the films
or film structures of the present invention, the packages made therefrom
are especially useful for packaging diagnostic test strips, medical
kits, instruments, and pharmaceutical and/or nutriceutical packaging.
[0040] Now referring to the drawings, wherein like numerals refer
to like parts, FIG. 1 illustrates a film 1 of the present invention.
The film 1 may be made from a polymeric material, such as a polyolefinic
material. Preferably, the film may comprise polyethylene selected
from the group consisting of ultra low density polyethylene, low
density polyethylene, linear low density polyethylene, medium density
polyethylene, and high density polyethylene, and may be made via
any known method of making polyethylene, such as via Ziegler-Natta
catalysts, or single-site catalysts, such as metallocene catalysts.
Moreover, the film may preferably comprise ethylene copolymers,
such as ethylene alpha-olefin copolymers, ethylene-methyl acrylate
copolymer, ethylene vinyl acetate copolymer, ethylene acrylic acid
copolymer, ethylene methyl acrylic acid copolymer, ionomer (Surlyn),
and other like polymers. In addition, the film may comprise polypropylene
homopolymer or copolymer, either alone or blended with polyethylene
or polyethylene copolymers, as noted above. In addition, the film
may comprise modified polymeric materials, such as modified via
maleic anhydride, or other like modifiers for polymeric materials
having particular characteristics. Specific materials that may be
useful as the sealant layer include DuPont APPEEL.RTM. and BYNEL.RTM..
[0041] The film 1 may further comprise a desiccant material 10
blended therein, such as any known desiccant material that may blend
with polymeric resins that can be made into films. Specifically,
desiccant materials that may be useful for the present invention
include, but are not limited to calcium oxide, magnesium oxide,
barium oxide, strontium oxide, aluminum oxide, partially hydrated
aluminum oxide, magnesium sulfate, sodium phosphate di-basic, ammonium
chloride, potassium carbonate, potassium aluminum disulfate, magnesium
chloride, diammonium sulfate, sodium nitrate, calcium chloride,
calcium sulfate, sodium chloride, potassium bromide, molecular sieves,
clays, or any other desiccant material useful for the present invention.
Chemical desiccant materials are preferred, such as calcium oxide,
magnesium oxide, barium oxide and strontium oxide.
[0042] Chemical desiccant materials are preferred because chemical
desiccant materials irreversibly bind water molecules within the
crystalline product via a chemical reaction. The water molecules
typically cannot be released into the package at higher temperatures
or lower pressures. In addition, chemical desiccant materials may
more effectively remove humidity from the headspace of a package
made from the film 1.
[0043] Hydrate-forming salts may also be used, and may effectively
maintain constant relative humidity levels within the headspace
of a package made from the film 1. For example, magnesium sulfate
may be blended with polyethylene or another polymeric material to
form a package that may maintain a relative humidity level inside
said package at about 35%. However, other levels of humidity may
be maintained depending on the hydration levels or state of the
magnesium sulfate within the polymer material.
[0044] A preferred chemical desiccant material that is useful for
the present invention is calcium oxide. Another preferred chemical
desiccant material is barium oxide, which irreversibly forms barium
hydroxide via a chemical reaction. In addition, the barium hydroxide
can further be utilized as a desiccant material because the barium
hydroxide can be utilized as a hydrate forming desiccant mateiral
wherein the barium hydroxide may form coordinated structure with
eight water molecules at various humidity levels.
[0045] The desiccant material can be incorporated into the film
1 at a level of between about one weight percent and about 90 weight
percent. More preferably, the desiccant material can be incorporated
into the film 1 at a level of between about 20 weight percent and
about 60 weight percent. Most preferably, the desiccant material
can be incorporated into the film 1 at a level of about 30 weight
percent.
[0046] Specifically, the film 1 may comprise a quantity of a masterbatch
of polymer and desiccant material. For example, the masterbatch
may preferably comprise polyethylene having calcium oxide blended
therein. Specifically, the masterbatch comprises about 50 percent
by weight polyethylene and about 50 percent by weight calcium oxide.
The masterbatch is further blended into another polymeric material,
such as low density polyethylene, in a ratio of about 60 percent
by weight masterbatch and 40 percent by weight low density polyethylene.
Therefore, the film 1 may preferably have a desiccant material content
of about 30 weight percent in the film 1. Alternatively, the masterbatch
is blended with a modified ethylene vinyl acetate copolymer or modified
ethylene methyl acrylate copolymer, such as DuPont APPEEL.RTM. resins,
to provide the sealant film structures with a peelable seal feature.
[0047] It should be noted that although the film 1 is illustrated
as a single independent layer, film 1 may be incorporated into a
multilayer structure such as via coextrusion with other film layers,
extrusion or coextrusion coating, adhesive lamination, extrusion
lamination or any other method of making multilayer film structures
having a sealant layer comprising a desiccant material with other
film layers.
[0048] FIG. 2 illustrates a film structure 100 of the present invention,
incorporating a film layer 110 having a desiccant material incorporated
therein, as detailed above with relation to the film 1. Specifically,
the film layer 110 may comprise a polyolefinic material, such as
polyethylene, as described above, or polypropylene. Preferably,
the polyolefinic material comprises polyethylene. The desiccant
material may comprise a chemical, physical, or hydrate-forming desiccant
material, although a chemical desiccant material is preferred.
[0049] In addition, the film layer 110 may be between about 1 mil
and about 10 mils thick and may form a sealant layer or a product
contacting layer in a package made from the film structure 100.
More preferably, the film layer 110 may be between about 1 mil and
5 mils thick. Most preferably, the film layer 110 can be between
about 1.5 mils and about 3.5 mils thick.
[0050] The film layer 110 may further comprise a component that
provides a peelable seal when used as a sealant layer that is heat
sealed to another film structure or to itself. A preferable resin
blend that allows for a peelable seal is DuPont APPEEL.RTM., which
is either modified ethylene vinyl acetate copolymer or modified
ethylene methyl acrylate copolymer, each of which is designed to
provide a peelable seal when heat-sealed to other film layers, such
as polyvinylchloride (PVC). Alternatively, a seal-poisoning component
may be utilized, wherein a material, such as polybutylene, may be
blended with the sealant resins to provide "poisoned seals"
when sealant layers made from such resins are heat-sealed to other
film layers, which can provide adequate sealing protection but can
be easily separable using digital pull-apart forces. In addition,
a desiccant material, such as calcium oxide (CaO) can be used as
the peelable seal component, such that when heat-sealed to another
film component, the film structure may be relatively easily separable
using digital pull-apart forces.
[0051] The material that provides the peelable seal, such as DuPont
APPEEL.RTM., may be present in the film structure at a weight percent
of between about 20 and about 60 weight percent of the film layer
110. More preferably, the peelable seal component may be present
in the film structure at between about 30 and about 50 weight percent
of the film layer 110. Most preferably, the peelable seal component
may be present in the film structure at about 40 weight percent
of the film layer 110. The peelable seal component may be blended
with another sealant layer resin, such as PVC, polyethylene terephthalate
(PET), and polyethylene, such as polyethylene that is selected from
the group consisting of ultra low density polyethylene, low density
polyethylene, linear low density polyethylene, medium density polyethylene,
and high density polyethylene. Further, the polyethylene may be
made via any known method of making polyethylene, such as via Ziegler-Natta
catalysts, or single-site catalysts, such as metallocene catalysts.
Moreover, the other sealant layer resin may comprise ethylene copolymers,
such as ethylene alpha-olefin copolymers, ethylene-methyl acrylate
copolymer, ethylene vinyl acetate copolymer, ethylene acrylic acid
copolymer, ethylene methyl acrylic acid copolymer, ionomer (Surlyn),
and other like polymers. In addition, the other sealant layer resin
may comprise polypropylene homopolymer or copolymer, either alone
or blended with polyethylene or polyethylene copolymers, as noted
above.
[0052] Alternatively, the peelable seal component may not be present
in the heat sealant layer, as described above, but may be present
in a heat sealable layer of a second film structure that is heat-sealed
to the film structure containing the desiccant material. This allows
the peelable film component to be present in either the film structure
containing the desiccant material or the second film structure that
the film structure containing the desiccant material is heat-sealed
to. In addition, the peelable seal component of the present invention
may be contained within the first tie layer of the film structure
containing the desiccant material, or alternatively, to a tie layer
of the second film structure that the film structure containing
the desiccant material is heat-sealed to. Therefore, it should be
noted that the peelable film component can be contained within any
layer or any film structure that allows the film structure containing
the desiccant material to be pulled from the second film structure
with digital pull-apart forces, while maintaining protection from
moisture prior to pulling the film structures apart.
[0053] The remaining film layers of a film structure of the present
invention may be any material that may be utilized to form a package
with the film layer 110 as a sealant layer or a product contacting
layer. Moreover, any number of layers may be incorporated into the
film structure 100 as may be needed to form a package having desired
characteristics. The preferred film structure of the present invention
includes the heat sealant layer 110 as noted above. The heat sealant
layer 110 may be adhered to a barrier layer 114 by a tie or adhesive
layer 112. In addition, the film structure 100 may comprise an outer
layer 120 adhered to said barrier layer via a second tie or adhesive
layer 116 disposed between said outer layer 120 and said barrier
layer 114. Finally, the film structure 100 of the present invention
may comprise a primer layer or printed layer 118 disposed between
said outer layer 120 and said tie adhesive layer 116.
[0054] Preferably, tie or adhesive layer 112 may be a coextrusion
of low density polyethylene (LDPE) and ethylene acrylic acid copolymer
(EAA), wherein said LDPE is disposed adjacent to the sealant layer
110 and the EAA is disposed adjacent to the barrier layer 114 as
described below, although other polymeric materials may be utilized
that adhere the heat sealant layer 110 to the barrier layer 114.
Barrier layer 114 may be made of a polyvinylidene chloride-methyl
acrylate copolymer, Honeywell ACLAR.RTM. (a high density fluorocarbon
polymer), metal foil, such as aluminum foil, nylon, high density
polyethylene, polypropylene, such as oriented polypropylene and
metallized oriented polypropylene, or metallized polyester, and
may be any thickness that may be necessary to reduce the transmission
of water molecules through the film structure 100. Preferably, the
barrier layer 114 may be about 0.35 mils when the barrier layer
114 is aluminum foil. Of course, the barrier layer may be other
thicknesses depending on the barrier material that is utilized.
The tie or adhesive layer 112 may aid in binding the polyolefinic
material of the heat sealant layer to metal foil that may be used
as the barrier layer 114. Tie or adhesive layer 116 may be a coextrusion
of LDPE and EAA and may be similar, if not identical, to film layer
112 wherein the EAA is disposed adjacent to the barrier layer 114
and the LDPE is disposed adjance to the film layer 118 or film layer
120 as described below. Film layer 118 may be a primer layer and/or
a printed layer. If the film layer 118 is a printed ink or pigment
layer, it may form a printed label or other printed indicia on the
film structure 100. Finally, film layer 120 may be an outer abuse
layer, and may comprise Honeywell ACLAR.RTM., polyethylene terephthalate
(PET), oriented polypropylene (OPP), polyethylene, nylon, foil,
metallized substrates, or any other material apparent to one having
ordinary skill in the art. Optionally, a secondary sealant layer
(not shown) may be disposed adjacent to the sealant layer 110 and
may protect the product from the desiccant material contained in
the sealant layer 110. The optional secondary sealant layer may
form the product contacting layer of the film structure 100 and
may be about 0.5 mils or less. However, the secondary sealant layer
may be any polymeric material that helps to protect the product
from contacting the desiccant material.
[0055] As stated above, the barrier layer 114 may be a metal foil
or Honeywell ACLAR.RTM. that may be any thickness to reduce the
transmission of moisture through the film. The number of pinholes
present in a metal foil, for example, is inversely related to the
foil thickness. Therefore, a thicker foil tends to have fewer pinholes.
However, if the desiccant material of the present invention is in
the heat sealant layer 110 thinner foil or ACLAR.RTM. can be utilized
in packages made from the film structure 100.
[0056] Metal foil or ACLAR.RTM. is typically utilized to provide
an effective barrier against moisture transmission through a film
structure. However, metal foil can be relatively expensive and difficult
to process. Therefore, the desiccant sealant layer 110 is effective
at reducing or eliminating the transmission of moisture that may
pass through relatively thin metal foil. Desiccant films, therefore,
add significant protection to the inside space of a package made
from the film structure 100 in addition to the inherent barrier
protection provided by metal foil. Barrier layers may be relatively
thinner when a film structure incorporates a desiccant sealant layer
into the film structure, thereby saving on cost.
[0057] FIG. 3 illustrates a package 200 made from a film structure
of the present invention. Specifically, the package 200 is made
from the film structure 100 as illustrated with respect to FIG.
2 described above. Specifically, the package 200 may comprise two
film structures that are heat sealed together via a heat seal 202
that is formed around a perimeter of the package 200. Alternatively,
the package 200 may comprise a single film structure that is folded
and heat sealed around the perimeter of the package 200. The package
200 may further comprise a space 204 to contain a product 206. The
product 206 may be sensitive to moisture, so that a desiccant material
contained within the film structure or film structures reduces or
eliminates the amount of water molecules within the space 204. A
preferable product contained within the package 200 may be a diagnostic
test strip or kit useful in the medical field. A single diagnostic
test strip or instrument may be contained within the package 200
so that when opened and the diagnostic test strip or instrument
is removed, there are no other test strips or instruments within
the package 200 to be contaminated by moisture.
[0058] FIG. 4 illustrates a cross-section of the package 200 along
line IV-IV, in an embodiment of the present invention. The cross-section
shows two film structures 210 212 that are heat sealed together
at heat seals 202. The two film structures may be identical, and
may comprise the same film layers as described above with respect
to film structure 100. Specifically, the two film structure 210
212 may comprise a plurality of layers: a sealant layer 110 of a
polyolefinic material and a desiccant material; a tie or adhesive
layer 112 comprising, for example, a blend of low density polyethylene
and ethylene acrylic acid copolymer; a barrier layer 114 comprising,
for example, a foil, ACLAR.RTM. or metallized material; a tie or
adhesive layer 116 comprising, for example, a blend of low density
polyethylene and ethylene acrylic acid copolymer; a printed or primer
layer 118; and an outer or abuse layer 120 comprising, for example,
PET. The product 206 such as a diagnostic test strip or instrument,
is contained within the package 200 in the space 204.
[0059] While foil can reduce or effectively eliminate water transmission
through film structures 210 212 of the package 200 it cannot completely
eliminate the transmission of moisture through the edges of the
film structure. For example, FIG. 4 illustrates the cross-section
of the package 200 along line IV-IV. As shown, the metal foil layer
114 of each film structure 210 and 212 are displaced from the portions
of the film structure 210 and 212 that are heat sealed together.
Therefore, there is an area 214 that is not protected by the metal
foil layer 114 that may transmit water molecules into the space
204. If the desiccant material is incorporated into the heat sealant
layer 110 then the desiccant material effectively blocks moisture
from passing into the interior space 204 of the package 200 thereby
protecting the moisture-sensitive product contained therein. In
addition, if the desiccant material is in the heat sealant layer
that contacts a moisture-sensitive product or other contacts the
interior space 204 the desiccant material can remove moisture molecules
that may be contained within the interior space 204.
[0060] FIG. 5 illustrates a package 300 in an alternate embodiment
of the present invention. More specifically, the package 300 may
comprise a base structure 302 having multiple cavities 303 disposed
therein for containing moisture-sensitive products therein. In addition,
the base structure 302 may be formed by a polymeric material that
provides an effective moisture barrier. For example, the material
may comprise a film layer 310 (as shown in FIG. 6) made from ACLAR.RTM.,
a high density fluorocarbon film having excellent water vapor barrier
properties. In addition, the base structure 302 comprises cavities
303 for storing or otherwise containing the moisture-sensitive products
305. The cavities 303 may preferably be formed in the base structure
302 using a thermoforming process or any other process for forming
the cavities 303 in the base structure 302. The moisture-sensitive
products 305 may preferably be pharmaceutical or nutriceutical products,
although any other moisture-sensitive product is contemplated by
the present invention.
[0061] The base structure 302 may be heat-sealed to a lidstock
structure 304. The lidstock structure may correspond to the film
structure described above with reference to FIG. 2. Specifically,
the heat sealant layer 110 of the lidstock structure 304 may be
heat-sealed to a forming layer 312 of the base structure 302 that
acts as a heat sealant layer for the base structure 302. The sealant
layer 110 may comprise the desiccant material so that moisture cannot
enter the cavities 303 along an edge 326 to damage any moisture-sensitive
products contained therein. Moreover, the sealant layer 110 may
further comprise a peelable seal component to allow a seal formed
by heat sealing the desiccant lidstock structure 304 to the base
structure 302 to be easily peelable. For example, the sealant layer
110 may comprise DuPont APPEEL.RTM. modified polymeric resin that
allows the sealant layer 110 to separate from the forming layer
312 of the base structure 302 using digital pull-apart forces. Alternatively,
both the heat sealant layer 110 of the lidstock structure 304 and
the forming layer of the base structure 302 may comprise an amount
of the desiccant material.
[0062] The package, as shown in FIGS. 5 and 6 may have perforations
306 such that the peelable film may only expose one cavity containing
the moisture-sensitive product when the sealant film is peeled from
the base structure. When the peelable sealant film structure is
peeled from the base structure, the peelable sealant film structure
may break at the perforations 306 thereby maintaining the barrier
properties of the other products contained within the other cavities.
The perforations 306 may alternately go all the way through the
package 300 such that each individual cavity may be removed from
the remaining cavities within the package by breaking the package
300 at the perforations 306.
[0063] Alternatively, the package 300 illustrated in FIG. 5 may
have a lidstock structure 304 as described above with reference
to FIG. 6 and a base structure that may be similar to the base
structure 302 described above. However, the base structure 302
may further comprise a heat sealant layer disposed adjacent to the
forming layer. The heat sealant layer may comprise a heat sealant
material comprising modified EVA or modified EMA, such as DuPont
APPEEL.RTM., or BYNEL.RTM., LDPE, EVA, ionomer, single site catalyzed
polyethylene, or the like. In addition, the heat sealant layer of
the base structure may comprise the desiccant sealant material,
such as, for example, calcium oxide, or the like. Having the desiccant
material in both the sealant layer 110 of the peelable sealant structure
304 and the base structure will make it more difficult for moisture
to travel through the edge of the package to the cavities within
the package. In addition, depending on the polymeric material that
is utilized in the heat sealant layer of the base structure, the
film may not be peelable as described above with respect to FIG.
6 when a heat-seal is formed between the lidstock structure 304
and the base structure 302. In this case, a notch or similar feature
may be provided in the package that allows the package to be torn
to gain access to the cavities disposed therein and, hence, the
moisture-sensitive products contained therein.
[0064] In an alternative package, the lidstock structure 304 may
not have a desiccant material disposed within the heat sealant layer.
The desiccant material may be contained only within heat sealant
layer of the base structure 302. For example, the base structure
may comprise a layer of ACLAR.RTM. and a forming layer of PVC disposed
adjacent the layer of ACLAR.RTM.. Disposed adjacent to the forming
layer of PVC may be a heat sealant layer comprising an amount of
the desiccant material blended with a polymeric material as described
above that is useful for a heat sealant layer.
[0065] The base structure may have a forming layer on either or
both sides of the ACLAR.RTM. layer. In addition, if a heat sealant
layer is incorporated into the base structure, the heat sealant
layer may be disposed directly adjacent to the ACLAR.RTM. layer
or, as described above, may be disposed adjacent to a forming layer.
Still further, a desiccant sealant layer may be provided adjacent
an extrusion coated layer of APPEEL.RTM., that may be disposed adjacent
to a layer of ACLAR.RTM. that may be disposed adjacent to a layer
of PVC.
[0066] FIG. 7 illustrates an alternate package 350 of the present
invention, whereby the base structure 302 is not utilized, but the
package is formed by identical desiccant sealant film structures
that are heat sealed together to form the package 350. Products
may further be vacuum packed so that the products are held in place
in individual cavities 353 by the desiccant sealant films forming
completely around the moisture-sensitive product. This may be especially
useful for brittle or otherwise easily-damaged products 355 that
would break if allowed to freely sit within a package. In addition,
perforations 356 may be contained within the package 350 so that
individual cavities may be separated from the other cavities.
[0067] FIG. 8 illustrates a cross-section of the package shown
in FIG. 7 along line VIII-VIII. As can be seen, the package consists
of two identical desiccant sealant film structures 352 354 that
are placed in face to face relationship with each other and heat-sealed
to form the cavities 353 to contain the products 355 therebetween.
A heat seal 358 is provided around the products 355 such that each
product is contained within an individual cavity. As noted above,
the package 350 may be vacuum-packed so that the sealant film structures
are tight around the products 355. Alternatively, the product may
be loosely contained within a cavity formed by the sealant film
structure that is disposed on a bottom of the package, similar to
the package described in FIGS. 5 and 6.
[0068] Each sealant film structure 352 354 may comprise the desiccant
sealant layer 110 the first tie or adhesive layer 112 the barrier
layer 114 the second tie or adhesive layer 116 the optional printed
or primer layer 118 and the outer abuse layer 120. The desiccant
sealant layer 110 may provide protection for the moisture sensitive
product 355 contained with cavities 353 from moisture that may attempt
to enter the package 350 along the edges of the package 350.
[0069] In addition, the film structures 352 354 may be made having
a peelable film component in the desiccant sealant layer 110 such
that the two film structures 352 354 are peelable from each other
using digital pull-apart forces. Alternatively, notches 368 may
be provided in the package 350 so that film structures 352 354
may be torn and the moisture-sensitive product contained therein
may be exposed. Alternatively, the film structure may be designed
to be torn without the notches 368.
[0070] The film structures 100 304 352 and 354 may be made via
cast coextrusion, extrusion coating and/or extrusion lamination,
adhesive lamination, blown-film coextrusion or monolayer extrusion
or any other film-making method generally known to those having
ordinary skill in the art. Preferably, the heat sealant layer may
be made by compounding the desiccant material into the polymeric
resin, and extruding or coextruding via blown extrusion, cast extrusion,
or extrusion lamination into a monolayer film or a multilayer film.
The remainder of the film structures may be extrusion or adhesive
laminated together with the monolayer film or multilayer film. The
desiccant heat sealant layer can be laminated to the remainder of
the film structure, including the barrier layer of the film structure.
[0071] As noted in the above paragraph, several methods exist for
constructing an effective flexible package using the present invention.
These methods include, but are not limited to:
[0072] 1. Blown film monolayer extrusion or multilayer coextrusion
of a desiccant sealant film that is extrusion laminated to a barrier
material. The sealant film may be utilized as either the lidding,
the base or both of the package. This method is preferred.
[0073] 2. Blown film monolayer extrusion or multilayer coextrusion
of a desiccant sealant film that is adhesive laminated to a barrier
material with the use of adhesives and/or primers to bond the desiccant
sealant film to the barrier layer. The film made by this method
may be utilized as either the lidding, the base or both of the package.
[0074] 3. Cast film monolayer extrusion or multilayer coextrusion
of a desiccant sealant film that is extrusion laminated to a barrier
layer. The film made by this method may be utilized as either the
lidding, the base or both of the package.
[0075] 4. Cast film monolayer extrusion or multilayer coextrusion
of a desiccant sealant film that is adhesive laminated to barrier
materials with the use of adhesives and/or primers to bond the desiccant
sealant film to the barrier layer. The film made by this method
may be utilized as either the lidding, the base, or both of the
package.
[0076] 5. Extrusion or coextrusion coating wherein the desiccant
sealant layer and/or an adhesive layer are extrusion or coextrusion
coated directly onto the barrier layer. The film made by this method
may be utilized as either the lidding, the base, or both of the
package.
[0077] Of course, any other methods of making films, film structures,
and packages of the present invention may be utilized as may be
apparent to one having ordinary skill in the art. Moreover, although
film structures having barrier materials incorporated therein as
a barrier layer of the film structures are preferred, other film
structures such as those not having a barrier material or barrier
layer may also be produced as apparent to one having ordinary skill
in the art.
[0078] In addition, in an alternate embodiment of the present invention,
the desiccant material may further be utilized to provide an indicator
showing whether the desiccant material has reached its capacity.
In addition, this may further provide an indication whether the
package integrity has been compromised. Generally, desiccant materials
become cloudy when they have absorbed water, especially when incorporated
into films that are transparent. In addition, when the desiccant
material absorbs moisture, the package becomes heavier, less transparent
and more opaque. An image or a message may be provided in a film
structure containing the desiccant material. When the image or message
is obscured to a certain point, such as when the image or message
cannot be viewed anymore because of the cloudiness of the package,
an individual may know that the desiccant material has reached its
capacity, or is close to reaching its capacity, thereby indicating
that the package, and therefore the product, is relatively old,
or the package has been compromised and moisture has entered the
package. Alternatively, the package may contain a moisture indicator
visible through at least a portion of the package, such as a window
or the like, to form or change colors, thereby indicating the presence
of excess moisture.
EXAMPLES
[0079] The following examples are illustrative of preferred embodiments
of the present invention, as described above, and are not meant
to limit the invention in any way.
Example 1
[0080] The following Table 1 illustrates preferred materials and
gauges for the film structure 100 as described above and illustrated
with respect to FIG. 2.
1 TABLE 1 Material Gauge PET 0.48 mils INK 0.1 #/ream LDPE/EAA
Coextrusion 0.5 mils Foil 0.35 mils LDPE/EAA blend 0.5 mils LDPE/CaO
blend 1.5 mils
Example 2
[0081] The following Table 2 illustrates preferred materials and
gauges for the film structure 100 as described above and illustrated
with respect to FIG. 2 in an alternate embodiment of the present
invention.
2 TABLE 2 Material Gauge PET 0.48 mils INK 0.1 #/ream LDPE/EAA
Coextrusion 0.5 mils Foil 0.35 mils LDPE/EAA blend 0.5 mils LDPE/CaO
blend 2.5 mils
Example 3
[0082] Example 3 is a preferred embodiment of the package 200
described above and illustrated with respect to FIG. 3. The package
may be made from film structures noted above, and preferably with
respect to Examples 1 and/or 2. Specifically, the package 200 may
be for diagnostic test strips or instruments. Each package may be
about 5.25 in. long and about 2.25 in. wide. The heat seals that
are created around the perimeter of the packages are about 0.25
in. wide. Taking into consideration the heat seals, each package
would have a total exposed internal surface of about 16.6 in..sup.2
Examples 4-6
[0083] The following table 3 illustrates preferred film structures
and gauges for a sealant film layer that is extruded as a monolayer
film or coextruded with a second layer, such as a tie or adhesive
layer, and is then laminated to other film layers, such as a barrier
layer, another tie or adhesive layer, an optional printed or primer
layer, and an abuse layer, to form the film structures 304 352
or 354 as described above with reference to FIGS. 5-8 in alternate
embodiments of the present invention. Each of the sealant films
is made via a blown extrusion method, although other methods are
available, such as cast extrusion.
3TABLE 3 Example Film materials Gauge 4 39% DuPont Appeel 2044
2.0 mil 60% Ampacet X101499 LLDPE of 60% by weight calcium oxide
1% Ampacet slip 7012125 5 49% DuPont Appeel 1184 2.0 mil 50% Ampacet
X101499 LLDPE of 60% by weight calcium oxide 1% Ampacet slip 7012125
6 59% DuPont Appeel 1181 2.5 mil 40% Ampacet X101499 LLDPE of 60%
by weight calcium oxide 1% Ampacet slip 7012125
[0084] After the sealant films are made using blown extrusion,
the films should be wrapped immediately with a moisture barrier
material to avoid being contaminated by moisture in the atmosphere.
Example 7
[0085] Table 4 illustrates an embodiment of the present invention,
whereby the sealant film layer, described above as Example 4 is
laminated to other film layers to form a sealant film structure.
4 TABLE 4 Film layer Materials Gauge Inner heat Example 4 described
above. 2.0 mils sealant layer First tie or EAA/LDPE Coextrusion
0.5 mils adhesive layer Barrier layer Foil 70 gauge Second tie or
EAA/LDPE Coextrusion 0.5 mils adhesive layer Print layer Ink 0.1
#/ream Outer abuse PET 48 gauge layer
[0086] The peel strength was measured as 300 grams with a heat
seal made at 320.degree. F. at 50 psi for 1.0 second.
Example 8
[0087] Table 5 illustrates an embodiment of the present invention,
whereby the sealant film layer, described above in Example 5 is
laminated to other film layers to form a sealant film structure.
5 TABLE 5 Film layer Materials Gauge Inner heat sealant Example
5 described above. 2.0 mils layer First tie or EAA/LDPE Coextrusion
0.5 mils adhesive layer Barrier layer Foil 70 gauge Second tie or
EAA/LDPE Coextrusion 0.5 mils adhesive layer Print layer Ink 0.1
#/ream Outer abuse layer PET 48 gauge
[0088] The peel strength was measured as 600 grams with a heat
seal made at 320.degree. F. at 50 psi for 1.0 second.
Example 9
[0089] Table 6 illustrates an embodiment of the present invention,
whereby the sealant film layer, described above in Example 6 is
laminated to other film layers to form a sealant film structure.
6 TABLE 6 Film layer Materials Gauge Inner heat Example 6 described
above. 2.5 mils sealant layer First tie or EAA/LDPE Coextrusion
0.5 mils adhesive layer Barrier layer Foil 70 gauge Second tie or
EAA/LDPE Coextrusion 0.5 mils adhesive layer Print layer Ink 0.1
#/ream Outer abuse PET 48 gauge layer
[0090] The peel strength was measured as 900 grams with a heat
seal made at 320.degree. F. at 50 psi for 1.0 second.
Example 10
[0091] Each of the sealant film structures, described above with
reference to Examples 7-9 can be utilized as lidding material and
may be heat-sealed to another film structure, such as a base structure
of a layer of ACLAR.RTM. and one or more layers of PVC, with an
alternative heat sealant layer, which has been thermoformed by the
application of heat and/or pressure to form individual cavities
for containing moisture-sensitive pharmaceutical or nutriceutical
products.
Example 11
[0092] Alternatively, each of the sealant film structures, described
above with reference to Examples 7-9 can be heat-sealed to identical
film structures to provide packages having spaces therein for moisture-sensitive
products, such as pharmaceutical or nutriceutical products.
Example 12
[0093] Table 7 illustrates an alternative film structure that may
be heat sealed to the sealant film structures described above with
reference to Examples 7-9. The sealant film structures can be heat
sealed to a base structure having a heat sealant layer comprising
an amount of a desiccant material.
7 TABLE 7 Film layer Materials Gauge Inner heat Example 6 described
above 2.5 mils sealant layer Extrusion APPEEL .RTM. .5 mils Coating
Forming layer PVC 6 mils Barrier layer ACLAR .RTM. 1 mil
[0094] Alternatively, the forming layer of PVC and the barrier
layer of ACLAR.RTM. may be switched. In addition, the extrusion
coating layer of APPEEL.RTM. may be replaced with an adhesive layer
such that the inner heat sealant layer may be adhesive laminated
to the remainder of the film structure.
[0095] It should be understood that various changes and modifications
to the presently preferred embodiments described herein will be
apparent to those skilled in the art. Such changes and modifications
may be made without departing from the spirit and scope of the present
invention and without diminishing its attendant advantages. It is,
therefore, intended that such changes and modifications be covered
by the appended claims. |