Note: Descriptions are shown in the official language in which they were submitted.
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FILMS HAVING A DESICCANT MATERIAL INCORPORATED
THEREIN AND METHODS OF USE AND MANUFACTURE
Field of the Invention
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 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 methods of using the film having a desiccant material
incorporated
therein.
Background of the Invention
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 may
also be
very sensitive to atmospheric moisture.
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.
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
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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.
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
inside
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-unite packages.
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.
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 product or medical device, the food
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.
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
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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.
~ 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.
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.
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 typically have different levels of
hydration,
humidity levels may remain a certain level without decreasing until the level
of
hydration changes.
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
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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.
Desiccant materials may also be used that form no hydrates, such as common
salt (NaCI) 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 continue to take up
water.
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:
Ca0 + H20 ~ Ca(OH)Z
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.
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.
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.
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 andlor 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.
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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.
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.
Other examples of typical packages or .products that would benefit from
desiccant material are electrostatic shielding packaging for electronic parts,
such as
printer cartridges, circuit boards, televisions, DVDs, printers, modems,
personal
computers, telecommunications equipment, etc., and in pharmaceutical and/or
nutriceutical packaging, such as inside pill bottle caps. 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.
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
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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
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.
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 and/or other products that may suffer from the deleterious effects
of
moisture. Specifically, diagnostic strips that are useful in health care may
be
packaged using a film having a desiccant material contained within a layer of
the film
to maintain the utility of the diagnostic strip. The desiccant material is
utilized to
control the moisture level within a package made by the film of the present
invention.
The desiccant materials may be utilized as an alternative to high cost and
marginally
effective desiccant sachets or beads that may ruin the product within the
package if
the desiccant sachet breaks open or is otherwise allowed to contaminate the
product
within the package.
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 may
contaminate products contained within packages if the sachets accidentally
release the
desiccant material into the package. Moreover, sachets or beads may be
unsightly and
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, they 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.
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
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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.
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.
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
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.
FIG. 2 illustrates a cross-section of a film structure having a film layer
comprising a desiccant material incorporated therein in another embodiment of
the
present invention.
FIG. 3 illustrates a perspective view of a package made by the film structure
in
an alternate embodiment of the present invention.
FIG. 4 illustrates a cross-section of the package along line IV-IV, in the
alternate embodiment of the present invention.
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Detailed Description of the Presently Preferred Embodiments
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.
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,
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.
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 calcium 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
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material apparent to one having ordinary skill in the art. Chemical desiccant
materials
are preferred, such as calcium oxide.
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. 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.
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.
Specifically, the film 1 may comprise a quantity of a masterbatch of polymer
and desiccant material. The masterbatch comprises 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.
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.
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
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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.
In addition, the film layer 110 may be between about 1 mils 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 mils and 5 mils thick. Most preferably, the film layer 110 can be
between
about 1.5 mils and about 3.5 mils thick.
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 presently preferred 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.
Preferably, tie or adhesive layer 112 may be a blend of low density
polyethylene (LDPE) and ethylene acrylic acid copolymer (EAA). Barrier layer
114
may be made of a 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 pin-holing and therefore reduce the transmission of gases
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 barner layer may be
other
thicknesses depending on the barrier material that is utilized. The EAA of tie
or
adhesive layer 112 may aid in binding the polyolefinic material of the heat
sealant
layer to the metal foil layer 114. Film layer 116 may be a blend of LDPE and
EAA
and may be similar, if not identical, to film layer 112. Film layer 118 may be
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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 polyethylene
terephthalate (PET), oriented polypropylene (OPP), polyethylene, nylon, foil,
metallized substrates, or any other material apparent to one having ordinary
skill in
the art.
As stated above, the barrier layer 114 may be a metal foil that may be any
thickness to reduce the transmission of moisture through the film. The number
of
pinholes present in a metal foil 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 can be
utilized in
packages made from the film structure 100.
Metal foil 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.
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 useful in the medical
field. A
single diagnostic test strip may be contained within the package 200 so that
when
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opened and the diagnostic test strip is removed, there are no other test
strips within the
package 200 to be contaminated by moisture.
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 first sealant layer 110 of a polyolefinic material and
a desiccant
material; a second layer 112 of a blend of low density polyethylene and
ethylene
acrylic acid copolymer; a third layer 114 of a foil material; a fourth layer
116 of a
blend of low density polyethylene and ethylene acrylic acid copolymer; a fifth
primer
layer 11 ~; and a sixth layer 120 of PET. The product 206, such as a
diagnostic test
strip, is contained within the package 200 in the space 204.
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. 3
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.
The film layers of the film structure 100 may be made via cast coextrusion,
extrusion coating and/or extrusion lamination, adhesive lamination, blown-film
co,extrusion 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 into a monolayer
film or
a multilayer film. The remainder of the film structure may be extrusion or
adhesive
laminated together with the monolayer film or mulitilayer film. The desiccant
heat
sealant layer can be laminated to the remainder of the film structure,
including the
barrier layer of the film structure.
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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:
1. Blown film monolayer extrusion or multilayer coextrusion wherein the
sealant film is extrusion laminated to a barrier material. This method is
preferred.
2. Blown film monolayer extrusion or multilayer coextrusion wherein the
desiccant sealant film 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.
3. Cast film monolayer extrusion or multilayer coextrusion wherein the
sealant film is extrusion laminated to a barrier layer.
4. Cast film monolayer extrusion or multilayer coextrusion wherein the
desiccant sealant film is adhesive laminated to barrier materials with the use
of
adhesives and/or primers to bond the desiccant sealant film to the barrier
layer.
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.
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.
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Examples
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
The following Table 1 illustrates preferred materials and gauges for the film
structure 100, as described above and illustrated with respect to FIG. 2.
Table 1.
Material Gauge
PET 0.48 mils
INK 0.1 mils
LDPE/EAA blend 0.5 mils
Foil 0.35 mils
LDPE/EAA blend 0.5 mils
LDPE/Ca0 blend 1.5 mils
Example 2
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.
Table 2.
Material Gauge
PET 0.48 mils
INK 0.1 mils
LDPEBAA blend 0.5 mils
Foil 0.35 mils
LDPE/EAA blend 0.5 mils
LDPE/Ca0 blend 2.5 mils
Example 3.
The following 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
14
CA 02492054 2004-12-17
WO 2004/000541 PCT/US2003/019298
package 200 may be for diagnostic test strips. 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.2
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.
