The present invention includes processes and resulting structures
for producing moisture absorbing desiccant entrained polymers. A
polymer is caused to assume a molten state, typically by applying
heat and melting the polymer. To achieve certain results in the
hardened end product, such as rigidity and durability, the polymer
normally acts as a moisture barrier in a solidified state, both
before and after melting. A desiccating agent is blended into the
polymer so that the desiccating agent is distributed within the
polymer. A channeling agent is also blended into the polymer so
that it is distributed within the polymer. Together, the polymer,
desiccating agent and channeling agent create a blended mixture.
The mixture is solidified so that the channeling agent forms passages
in the mixture through which moisture is communicable to desiccating
agent that is entrained within the mixture. The solidified mixture
may be used to form plug type inserts and liners for closed containers,
or it may be used for producing laminated sheeting employed as package
What is claimed and desired to be secured by Letters Patent is
1. The composition having veined domains of channeling agents comprising
at least three components:
(a) wherein component A is a polyolefin;
(b) wherein component B is a channeling agent consisting of a hydrophilic
material that is heated above its melt point during processing of
(c) wherein component B is substantially separate from component
A and forms channels;
(d) wherein component C is a desiccating agent;
(e) wherein the volume fraction of component A represents at least
about 50% by volume of the total volume of components A, B and C;
(f) wherein the preferential affinity between component B and component
C is greater than between components A, and component C;
(g) wherein at least two aggregates are formed, one aggregate is
composed of a majority of components A, and the second aggregate
is composed of a majority of component B and a majority of component
(h) wherein component B forms channels for moisture transmission
through the polymer.
2. The composition of claim 1 wherein the polyolefin is selected
from the group consisting of polyethylene and polypropylene.
3. The composition of claim 1 wherein the desiccating agent is
selected from the group consisting of silica gel and molecular sieve.
4. The composition of claim 1 wherein the composition is formed
into a shaped article.
5. The composition of claim 4 wherein the shaped article is a
sheet for use as a packaging wrap.
6. The composition of claim 1 wherein the range of desiccating
agent is between about 40% to about 60% by weight of the total composition.
FIELD OF THE INVENTION
This invention relates generally to the use of desiccant material
in packaging; more particularly, the present invention relates to
packaging material having a desiccant contained therein. Still more
particularly, the present invention relates to polymers having desiccating
agents applied to or blended or mixed therein. The invention further
relates to desiccant entrained polymers that include means by which
desiccant located within interior portions of the polymer structure
are exposed to moisture that is exterior to the polymer body. The
desiccant entrained polymer of the present invention is particularly
useful in the manufacture of containers and packaging for items
requiring moisture reduced environments.
BACKGROUND OF THE INVENTION
There are many articles that are preferably stored, shipped and/or
utilized in an environment that is as moisture free as possible.
Therefore, containers having the ability to absorb excess moisture
trapped therein have been recognized as desirable. One application
in which moisture absorbing containers are desired is for the shipment
and storage of medications whose efficacy is compromised by moisture.
The initial placement of medicines into a sealed moisture free container
is usually controllable. Furthermore, the container for the medicine
is selected so that it has a low permeability to moisture. Therefore,
the medication will normally be protected from moisture until it
reaches the end user. Once the medicine is received by the consumer,
however, the container must be repeatedly opened and closed to access
the medication. Each time the container is opened and unsealed,
moisture bearing air will most likely be introduced into the container
and sealed therein upon closure. Unless this moisture is otherwise
removed from the atmosphere or head space of the container, it may
be detrimentally absorbed by the medication. For this reason, it
is a well known practice to include a desiccating unit together
with the medication in the container.
Other items, such as electronic components, may require reduced
moisture conditions for optimal performance. These components may
be sealed in containers, but excess moisture that is initially trapped
therein must be removed. Furthermore, the housings may not be completely
moisture tight, and moisture may be allowed to seep into the container.
This moisture must also be retained away from the working components.
For these reasons, it is important to include a desiccating agent
within the housing for absorbing and retaining excess moisture.
Because of the delicacy of many of the components that are to be
protected from the moisture, it is important that the desiccant
used not be of a "dusting" nature that may contaminate
and compromise the performance of the components. Therefore, it
has been recognized as advantageous to expose a desiccating agent
to the interior space of such containers, while at the same time
shielding the working components from actual contact with the desiccating
material, including desiccant dust that may be produced therefrom.
In other instances, moisture may be released from items that have
been placed in containers or sealed in packaging wrap for shipping
and/or storage. Prime examples of such items are food stuffs that
release moisture during shipping and storage. In the instance of
containers that are sealed and substantially impermeable to moisture,
the released moisture will remain within the container about the
product. If not removed, this released moisture may have ill effects
on the very item that released the moisture. It has been found that
a substantial amount of moisture is released from certain food products
within the first forty-eight (48) hours after manufacture and packaging.
This released moisture will remain about the product until removed.
If the moisture is not removed shortly after its release, it may
cause the food to degrade into a condition that is not saleable.
In these cases, desiccants may be included together with the contained
items to continually absorb the released moisture until the product
is unpacked. In this way, a relatively dry environment is maintained
about the stored item.
The need to eliminate moisture from within sealed containers has
been previously recognized. Early attempts to achieve these goals
included the provision of desiccant materials in fabric or similar
bags that are placed in the containers, together and commingled
with the matter being shipped or stored. A consumer related problem,
however, exists when the desiccant is loose and commingled together
with consumable items. If not carefully and thoroughly processed
upon unpacking, the desiccant may not be separated from the consumables
and could harm a person if unknowingly ingested.
Several inventions have been patented that include both structures
and processes that provide means for absorbing moisture by way of
a desiccant that is included in various forms of packaging. A most
basic example is found in the disclosure of U.S. Pat. No. 3326810
issued Jun. 20 1967 to Dolan et al for a DESICCANT PACKAGE. That
patent includes disclosure of a non-dusting silica gel desiccant
bag. The bag is created from two sheet of nylon mesh that are bonded
into a bag within which the silica gel is contained. The nylon mesh
has micro-porous polyurethane bonded to it and through which moisture
passes while at the same time containing the desiccating silica
gel within the bags interior. It is explained that the micro porous
structure of the polyurethane allows the moisture to be transmitted
thereacross, but is nonpermeable to desiccant dust that may be produced
by the silica gel.
Another known method by which a desiccant is included in a container
is to provide a special side-compartment having limited exposure
to the interior of the container. Within the side-compartment, desiccating
materials or drying agents are held for the purpose of absorbing
moisture that is present within the primary portion of the container.
Examples of such inventions are found in U.S. Pat. No. 4834234
issued May 30 1989 to Sacherer et al for a CONTAINER FOR TEST STRIPS.
Sacherer provides a drying agent cell or compartment within the
cap portion of a container for test strips that are used in the
analysis of body fluids. Those strips must be maintained in a moisture
reduced environment for which Sacherer's invention is intended.
It is disclosed that the drying agent cell is covered by a water
vapor-permeable cardboard disc that separates that cell from the
interior of the container. It is the cardboard disc that provides
a barrier between the desiccant or drying agent and the container's
interior space. A similar example is found in U.S. Pat. No. 5114003
issued May 19 1992 to Jackisch et al for a TABLET VIAL WITH DESICCANT
IN BOTTOM. Jackisch includes disclosure of a desiccant canister
that is secured to the bottom inside of a container's base. The
desiccant canister within which the desiccating material is contained
is initially sealed to prevent the absorption of moisture. Immediately
prior to use, the desiccant canister is punctured and communication
of moisture across the container is allowed to the desiccant.
Oftentimes, separate capsules of desiccant that are expensive to
produce are provided within the packaging. U.S. Pat. No. 4783206
issued Nov. 8 1988 to Cullen et al for an ADSORBENT CARTRIDGE describes
an elongated hollow cylindrical body fabricated of polyethylene,
polyester or polypropylene. It is intended that the sides of the
body member of the cartridge be moisture impermeable and that membrane
disc coverings be provided as end caps to the cartridge's body through
which moisture, odors and other gases are permeable. A desiccating
agent is enclosed within the cartridge thereby maintaining the desiccant
separate from other items commonly contained within the common container.
By the cartridge's construction, it is intended that moisture pass
only through the end caps constructed of spun-bonded polyolefin,
and not the rigid, high density plastic side walls of the cartridge.
A DRYING CAPSULE is disclosed in U.S. Pat. No. 2638179 issued
May 12 1953 to Yard. The drying capsule of Yard includes a desiccant
that is encapsulated within a moisture permeable skin. The desiccant,
which is contained within the capsule, absorbs moisture from the
skin, and not directly from the outside atmosphere. The gelatin
capsule is used as a regulator for governing the rate at which moisture
is absorbed by the desiccating agent. In some instances, the desiccating
agent may be very vigorous in its action and would absorb moisture
too quickly if not coated by the prescribed capsule or skin. It
is also the capsule that provides a barrier between the desiccant
agent and the items to be stored together therewith.
The patented inventions described above each provide a compartment
within which a desiccating agent is contained and separated from
a primary storage compartment of a container by a physical barrier.
The compartment within which the desiccant is carried may, or may
not be fixed to prevent relative movement between it and the storing
container. An important and primary function of the enclosure about
the desiccant is to provide a barrier between the desiccant agent
and the primary storage compartment while at the same time permitting
the transmission of moisture thereacross. In each instance, there
is no means for preventing the formation of desiccant dust, but
instead a means for keeping it separate and apart from the other
products is provided. The potential for the barrier being compromised
is ever present and the possibility of desiccant dust contaminating
the stored items is possible.
It is also known to entrain desiccant directly into plastics and
rubbers. An example of such entrainment is found in U.S. Pat. No.
3245946 issued Apr. 12 1966 to O'Connor et al for RUBBER AND
PLASTIC FORMULATIONS AND PROCESS. Therein, the entrainment of a
desiccating agent into rubber, plastic, and resin formulations during
their production is utilized to contain moisture produced during
the manufacture of those materials that would otherwise adversely
affect the produced material. There is no contemplation that the
included desiccant will have residual capabilities that may be utilized
in subsequently manufactured products beyond the material's original
A flexible desiccant body is disclosed in U.S. Pat. No. 4013566
issued Mar. 22 1977 to Taylor. Therein, a desiccant material is
homogeneously distributed and bound in a moisture transmissive aliphatic
epoxy polymer matrix. Therein, it is specifically recognized that
polypropylene bags are not suited as containment materials because
of potential attrition problems due to melting or thermoplasticity
of the bags during use. It is explained that an important aspect
of the Taylor invention is that the polymer be elastomeric so that
it retains flexibility and the capability to absorb vibrations and
mechanical shocks. Furthermore, it should be moisture transmissive
so that the desiccant material bound within the matrix may receive
trapped moisture within the solid body. It is explicit from the
Taylor disclosure that polypropylene, because of its characteristics
as a moisture barrier, would not be used as a moisture transmissive
polymer matrix of this invention and within which a desiccant agent
would be entrained. Furthermore, it is expressly stated that such
polymers as polyethylene would not be utilized because of their
rigid nature which may result in cracking, attrition and insufficient
water absorption capacity.
Another instance in which desiccant agents have been combined with
polymers is found in layered plastic sheeting in which an interior
oxygen impermeable layer must be protected against moisture which
compromises the oxygen barrier characteristics of that interior
layer. Examples of such utilization of a desiccant in a layered
structure may be found in United States patents that are assigned
to the American Can Company of Greenwich, Conn. and to the Kuraray
Co., Ltd. of Kurashiki, Japan. Those U.S. Pat. Nos. include 4407897;
4425410; 4464443 and 4792484. In the disclosure of these several
patents, the laminated structure has an interior layer that serves
as an oxygen barrier and is manufactured from such polymers as ethylene-vinyl
alcohol (EVOH); in each instance, the EVOH is provided solely as
an oxygen barrier. These EVOH layers serve as oxygen barriers as
long as their moisture content remains below certain levels. In
at least one application described in those patents, the layered
packaging is used for food products that must be sterilized in a
retorting process in which the food product, together with the packaging
is steam treated. During the steam treatment process, the protective
outer layers which are commonly manufactured from polypropylene
and polyethylene and moisture impermeable at lower temperatures,
permit the transmission of moisture thereacross at the elevated
temperatures of the retorting process. This moisture must be removed
and carried away from the EVOH layer after the retorting procedure
to regenerate that layer's oxygen barrier characteristics. To effect
the removal of moisture from the layer, desiccant is added to the
adhesive layers adjacent to the EVOH layer. The sole purpose of
the desiccant included in the structure of these several patents
is to control the moisture levels within the oxygen barrier layer
within the interior of the layered sheets. It is not contemplated,
nor intended that any desiccant included within the laminate structure
would have desiccating abilities outside the exterior moisture barrier
layers of the laminate; those exterior layers typically being constructed
from polyethylene, polypropylene, or a blend of the two. In any
event, the only purpose of the described inventions of those patents
to maintain the interior EVOH layer of the laminate at relatively
low moisture levels to assure its performance as an oxygen barrier.
An example of a desiccating agent being combined with a polymer
binding material is found in U.S. Pat. No. 4665050 issued May
12 1987 to Degen et al for SELF-SUPPORTING STRUCTURES CONTAINING
IMMOBILIZED INORGANIC SORBENT PARTICLES AND METHOD FOR FORMING THE
SAME. Therein, it is explained that sorbent particles are mixed
into a softened, but not melted thermoplastic material such as polyethylene
or polypropylene. By only softening the polymer medium, "blinding"
of the sorbent material is prevented. That is, exterior portions
of the sorbent material must be exposed and not blocked by the surrounding
polymer. In this manner, moisture is transmitted into the sorbent
material at those locations that are not covered by the binding
polymer. It is explained that the polymer should only be softened
to an extent that it becomes slightly tacky and does not become
so viscous as to flow.
The combination of a moisture-absorbent substance with a thermoplastic
resin is disclosed in U.S. Pat. No. 5078909 entitled MOISTURE-ABSORBENT
COMPOSITIONS AND MOLDED ITEMS that issued Jan. 7 1992 to Shigeta
et al. Therein, it is contemplated that a thermoplastic resin, which
may include polyethylene, polypropylene, as well as others may be
employed in the formation of the composition. The inclusion of various
additives are contemplated in the Shigeta disclosure which may include
color indicators that respond to the moisture content of the composition,
as well as foaming agents that may be mixed together with the other
substances to produce a composition that is light in weight and
has high moisture absorption properties both in its outer and inner
Prior to the present invention, the establishment of channels throughout
a desiccant entrained polymer has not been known. The present invention,
has been developed in response to a recognized need for structures
constructed from polymers that normally act as moisture barriers
in their solid, rigid state, but when produced according to the
present invention have a desiccant entrained therein which is capable
of absorbing moisture exterior to the polymer.
SUMMARY OF THE INVENTION
The apparatus and method of the present invention makes it possible
to provide a polymer matrix within which a desiccant agent is entrained
in the structure of the product itself or in an appropriate insert
therefore. In each instance, a means is provided by which moisture
is communicable to most, if not all of the entrained desiccant,
including that which is located most internally within the matrix.
As has been described above with respect to previously patented
inventions, it is known to entrain a desiccant within a polymer
base for the purpose of fixing the desiccant with respect to the
polymer and then using the combination in the manufacture of other
items. The sole purpose of the earlier combinations was to reduce,
if not eliminate, desiccant dust that may precipitate from desiccant
particles confined in other ways. Many types of packaging and containers
are manufactured from plastics and are selected based on the properties
and performance characteristics of the plastic in each application.
In some instances, flexibility is important when the packaging is
utilized as plastic wrap for articles or in the construction of
pouch or bag-type containers. In these cases, plastic sheeting is
often utilized that may be folded or otherwise positioned about
an object and then sealed to prevent foreign matter from contaminating
the enclosed items. In some instances, the housed item may be moisture
sensitive and for that reason it is desirable to have packaging
with desiccating abilities that will absorb moisture trapped within
the interior of the package and retain it within its structure away
from the item so that the item is protected and preserved.
In other applications, containers may be desirably constructed
from a rigid material that maintains its form and resists breakage
and deformation of the container. Like the plastic wrap, items may
be stored within the rigid containers that also require minimized
moisture conditions. For that reason, it is desirable to similarly
entrain or combine desiccating agents within these plastics which
harden and form a rigid structure or container. Many of the plastic
or polymer matrixes within which the desiccant agent will be entrained
is substantially moisture impermeable so that desiccant entrained
within the interior of the plastic, and not exposed at the surface
of the plastic body, will be unable to absorb and retain moisture.
One solution has been to locate the desiccant at the polymer's surface.
This, however, has not proved to be entirely satisfactory in that
greater amounts of desiccant may be required to remove sufficient
amounts of moisture to protect the items that are to be packaged.
For that reason, the present invention has been developed as a result
of desiring to entrain desiccating agent throughout a greater portion
of a rigid plastic body or container, while at the same time providing
means by which moisture may be communicated to most, if not all
of the desiccant that has been entrained therein. To do so will
permit a plastic structure to be more greatly loaded with desiccant
thereby enhancing absorption capacities.
As previously stated, a primary drawback of entraining a desiccant
within a rigid polymer matrix is the creation of a moisture impermeable
polymer encasement about the individual desiccant particles contained
within the structure. The present invention discloses both a structure
and a method by which passages are established throughout the polymer
matrix that communicate the entrained desiccant particles to the
appropriate areas of the exterior of the plastic body in a manner
that permits moisture to migrate from outside the plastic structure
to interior locations where the desiccant particles are positioned.
Furthermore, these channels or veins through which the moisture
is permitted to travel may be occupied by agents or compounds that
absorb and transport moisture at rates even greater than those achieved
by the desiccant. These transporting agents, however, are unable
to absorb significant quantities of moisture and retain those quantities
therein. For that reason, the transporting agents are used to act
as bridges from the surface of the plastic bodies inwardly to the
desiccant particles positioned within the plastic structure.
It has been discovered that certain compounds, which are referred
to herein as channeling agents, may be combined with a polymer base
matrix that is used in the formation of rigid bodies, including
at least portions of closeable containers. In practice, the polymer
base material into which the desiccant agent and channeling agent
are blended and mixed include as examples, polyethylene and polypropylene,
each of which are particularly suited for use in the construction
of rigid containers. Most often, these containers will be injection
or blow molded from molten polymer.
The desiccant and channeling agent may be added to the polymer
when the polymer base is in a molten state prior to forming it into
a container so that these additive agents may be blended and thoroughly
mixed throughout the base polymer material. After thoroughly blending
the several materials together and the mixing process is subsequently
stopped, the channeling agent will separate from the polymer base
and form veins or channels that act as moisture communicating passages
throughout the polymer. Ethylene-vinyl alcohol (EVOH) and polyvinyl
alcohol (PVOH) have been found to be particularly suited as channeling
agents. Each of these alcohols may be mechanically mixed with base
polymers, such as polypropylene and polyethylene, and then allowed
to separate into domains while still in the molten state. The polymer
base and channeling agents do not separate out into distinct levels
or phases, one above the other, but instead establish veined domains
of channeling agent that extend across the polymer base thereby
establishing channels or passages through the polymer. The channels
are open at the surface of the polymer structures and thereby provide
access for moisture to interior portions of the polymer matrix.
Alternatively, the desiccant material may be added on top of a
polymer base during a thermal forming process of sheets of plastic
Various types of desiccating agent are known in the art and most
may be used in mixtures with polymer bases. Similarly, most can
also be used in the mixtures of the present invention that contain
both polymer and channeling agents. There are three primary types
of desiccating agents. The first type comprises chemical compounds
that form crystals that contain water. Examples of such desiccant
are anhydrous salts which tend to absorb water or moisture and form
a stable salt. In this reaction with the moisture, a stable compound
is formed within which the moisture is held and prevented from release.
A second type of desiccant compounds are those which are considered
to be reactive. These compounds typically undergo a chemical reaction
with water or moisture and form new compounds within which the water
is combined. These newly formed compounds are generally irreversible
at low temperature and require a significant amount of energy to
be regenerated so that they may be reused as a desiccant. These
reactive type desiccants are mainly used in solvent drying and as
additives to polymers which must themselves be maintained in a moisture
reduced state. One application in which these reactive type compounds
are particularly suitable was described above with respect to the
multi-layer sheeting within which a layer of EVOH is laminated between
two shielding layers of what is normally moisture impermeable material
such as polypropylene or polyethylene. As earlier noted, however,
these types of sheeting or wrap are used to package food products
which must subsequently be sterilized in a retorting process wherein
the packaged good is exposed to hot sterilizing steam. At the elevated
temperatures, the exterior layers permit moisture to pass therethrough
and compromise the oxygen barrier effectiveness of the EVOH interior
layer. Because of the reactive desiccant that has been entrained
either in the EVOH are proximate thereto, that moisture is absorbed
into the desiccant and retained therein away from the EVOH layer
thereby reconstituting its oxygen barrier characteristics.
The third type of desiccants obtain their moisture absorbing capabilities
through physical absorption. The absorption process is accomplished
because of a fine capillary morphology of the desiccant particles
which pulls moisture therethrough. The pore size of the capillaries,
as well as the capillaries' density determine the absorption properties
of the desiccant. Examples of these physical absorption desiccants
include molecular sieves, silica gels, clays and starches. Because
these types of physical absorption desiccants are both inert and
non-water soluble, they are preferred for many applications. Among
other reasons, these innocuous characteristics are particularly
compatible with food products and medicinal products that may be
enclosed within containers formed from the desiccant entrained polymers,
or at least exposed thereto. As stated previously, however, any
of the three types may be employed within the polymer bases of the
present invention for the purposes of producing a desiccant entrained
polymer. Suitable desiccating agents include silica gel, molecular
sieve and naturally occurring clay compounds which would also include
montmorillimite clay. Similarly, all three types of desiccant may
be compatible with most channeling agents that are employed.
In practice, the polymer based matrix, the desiccating agent, and
the channeling agent will be mixed together while at least the polymer
base is in a molten, and typically liquid state. Because of the
relatively fine size of the desiccant particles, it is advantageous
to have many small channels or passages throughout the polymer base,
as opposed to a few large channels that will expose less surface
area within the polymer solid. For that reason, dimer agents may
be optionally added to the mixture reducing viscosities and increasing
the mixing compatibility of the base polymer and channeling agent.
By increasing their compatibility, the channeling agent separates
from the polymer with which it has been mixed into finer, more capillary-like
veins, instead of larger, more artery-like veins. In this way, the
more widely dispersed and finer passages expose more of the desiccant
particles bound within the polymer matrix.
It has also been found advantageous to select desiccating agents
having a polarity that causes an infinity between the desiccant
and the channeling agent. An example of such a polar desiccant is
silica which is attracted and more compatible with the EVOH channeling
agent than it is with the polypropylene or polyethylene polymer
base. For this reason, during the separating process when the channels
are formed throughout the polymer base, the desiccating agent will
also migrate toward the channeling agent domains to which it is
attracted. In this manner, the channeling agent is truly permitted
to act as a bridge between moisture located exteriorly to the polymer
structure and the desiccant that is located within the polymer.
This is particularly true with respect to desiccant that is bound
within the channeling agent filled passages. Polar plastisizers
such as glycerin may be further added to the mixture which enhance
the dispersion or mixing of desiccant into the channeling agent.
EVOH and PVOH are hydrophilic and truly act as a moisture bridge
through the hydrophobic polypropylene or polyethylene polymer base
because of its relatively fast rate of transmission of moisture
thereacross. The desiccating agent which is primarily concentrated
within the channeling agent picks up the moisture from the transmitting
channeling agent and retains it therein. In this way, the moisture
is quickly pulled throughout the channels or passages and made available
to the desiccating particles or agents which are dispersed throughout
the plastic body.
It has been found that the higher the desiccant concentration in
the mixture, the greater the absorption capacity will be of the
plastic structure created therefrom, however, that body will be
more brittle and the mixture will be more difficult to either thermally
form, extrude or injection mold. For that reason, it has been found
to be advantageous to have a maximum desiccant load of approximately
sixty percent by weight with respect to the polymer base. It is
preferred to maintain the load within a forty-five to fifty percent
range for optimal performance in certain applications such as those
that require a rigid structure. Similarly, in the instance of polypropylene
being used as the polymer base or phase, its content should be maintained
at about forty percent by weight, or greater to assure its performance
Because the desiccant entrained polymer is more brittle than polymer
without the desiccant, it has been found advantageous to mold containers
so that an interior portion of the container is desiccant entrained
while the exterior portions are formed from more pure polymer. In
this form, the containers will not only be more durable and less
brittle, but it will also act as a moisture barrier that resists
the transmission of moisture from the exterior into the interior
of the container. In this manner, the moisture absorption capacity
of the desiccant agent is potentiated by exposing it exclusively
to the interior of the container from which it is desired that moisture
be withdrawn and retained therefrom.
As has been previously discussed, the desiccant entrained polymer
of the present invention has many applications. A preferred use,
however, is the construction of rigid containers that are suitable
for containing relatively small volumes of product such as food
stuffs and medicines. In many cases, these types of products must
be shipped and stored in reduced moisture environments. Therefore,
it has been found to be particularly advantageous to mold container
bodies from polymers such as polypropylene and polyethylene to exploit
their moisture barrier characteristics. Desiccant entrained polymer
inserts may be constructed according to the present invention for
inclusion within the interior of the container. One form of insert
is a plug of any suitable shape formed from desiccant entrained
polymer. While the plug would serve its purpose by being merely
deposited within the moisture barrier container, it may also be
fixed to an interior location so that it does move about within
the interior space. In one particular embodiment, it is anticipated
that a plug formed into a disc may be shaped and sized to be pressed
fit into the bottom of a polymer formed container.
In a manner similar to that used with respect to the disc insert
described immediately above, a liner may be formed from the desiccant
entrained polymer that has an exterior surface substantially conforming
to an interior surface of the polypropylene container body. Like
the disc, the liner may be sized so that it may be press-fit into
position within the polymer body where it is held sufficiently snugly
to prevent its unintended disengagement therefrom. Alternatively,
either the plug or liner may be initially constructed and allowed
to harden, and then the container body subsequently constructed
thereabout so that the greater shrinkage characteristics of the
polymer body not containing desiccant tightly shrink-fits the container
body about the plug or liner so that neither becomes easily disengaged
from the other. In still a further embodiment, the insert taking
the form of either a plug or a liner may be substantially simultaneously
comolded with the polymer container body so that each is integrally
joined with the other. In the event of a comolding process, the
viscosities of the desiccant laden insert and the polymer container
body should be approximately equal to facilitate the proper and
desired location of the two phases of liquid or molten material
that are molded together.
In yet another embodiment, the desiccant entrained polymer may
be used to form sheeting that is joined with a nen-desiccant entrained
polymer sheet. In at least one embodiment, the sheets are effectively
laminated one to the other so that an exterior layer may be established
adjacent to the desiccant entrained layer which is substantially
moisture impermeable. The laminate sheet may then be used to wrap
an item which is to be stored in a moisture-reduced environment.
One means by which the joinder process may be accomplished is through
a thermal extrusion procedure.
In each of the embodiments of the present invention described herein,
advantages and enhancements over the prior art methods and structures
stem from the discovery of the ability to create passages throughout
a desiccant entrained polymer so that a rigid body may be constructed
from the polymer while also exposing the entrained desiccant to
moisture exterior to that structure. Furthermore, the discovery
of employing EVOH and similar type compounds as a channeling agent
that also acts as a moisture bridge between the exterior of the
polymer body and interiorly located desiccant greatly enhances the
structures' ability to quickly remove moisture located exteriorly
to the entrained structure, while at the same time taking advantage
of a greater portion of the desiccating capacities of the desiccating
agent entrained therein.
One embodiment of the present invention includes a process for
producing a moisture absorbing desiccant containing polymer. The
process comprises causing a polymer that acts as a moisture barrier
in a solidified state to assume a molten state. A desiccating agent
is blended into the polymer so that the desiccating agent is distributed
within the polymer. A channeling agent is blended into the polymer
so that the channeling agent is distributed within the polymer thereby
creating a blended mixture. The mixture is solidified so that the
channeling agent forms passages in the mixture through which moisture
is communicable to desiccating agent entrained within the mixture.
In one embodiment, the blended mixture is used to form a plug for
inclusion within a container constructed of a moisture barrier substance.
In another, the mixture is used to form a liner for inclusion within
a container constructed from a moisture barrier substance. In still
another embodiment, the mixture is used to form a desiccating sheet.
The desiccating sheet may optionally be combined with a barrier
sheet constructed of a moisture barrier substance for use as a packaging
In another embodiment, the present invention includes a process
for providing a moisture absorbing insert for a container. A desiccating
agent and a channeling agent are blended into a polymer that acts
as a moisture barrier in a solidified state thereby forming a mixture.
The mixture is solidified so that the channeling agent forms passages
in the mixture through which moisture is communicable to the desiccating
agent entrained within the mixture.
Another embodiment of the present invention includes a method for
making a desiccating container that includes forming a container
from substantially moisture impermeable material so that a moisture
barrier is created between an interior and exterior of the container.
An insert is formed from desiccant bearing material, the insert
having an exterior surface configured for mating engagement with
at least a portion of an interior surface of the container. The
insert is installed into the interior of the container so that at
least a portion of the exterior surface of the insert abuttingly
engages the interior surface of the container. The engagement fixes
the insert relative to the container and resists disengagement of
the insert from the container.
In still a further embodiment of the present invention, a desiccating
enclosure is provided that includes a container formed from substantially
moisture impermeable material so that a moisture barrier is created
between an interior and exterior of the container. A liner is formed
from desiccant bearing material so that the liner has an exterior
surface configured for mating engagement with at least a portion
of an interior surface of the container. The liner is inserted into
the interior of the container so that at least a portion of the
exterior surface of the liner abuttingly engages the interior surface
of the container and the engagement fixes the liner relative to
the container and resists disengagement of the liner from the container.
Another embodiment of the present invention is a desiccating insert
for a closeable container. The desiccating insert is configured
for installation into a closable container and is constructed from
thermoplastic that is entrained with a desiccating agent. The desiccating
agent is distributed substantially evenly throughout an interior
of the insert. The insert has channels extending from an exterior
surface of the insert into the insert's interior through which moisture
is passable thereby exposing portions of the desiccating agent located
within the interior of the insert to moisture located exteriorly
to the insert for absorbing and retaining that exteriorly located
Among those benefits and improvements that have been disclosed,
other objects and advantages of this invention will become apparent
from the following description taken in conjunction with the accompanying
drawings. The drawings constitute a part of this specification and
include exemplary embodiments of the present invention and illustrate
various objects and features thereof.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of a plug, insert, or tablet constructed
from channeled, desiccant entrained polymer showing, in an exaggerated
scale, the openings of the channels at the exterior surface of the
FIG. 2 is an exaggerated, cross-sectional view of a solidified
plug formed from a polymer mixture having a channeling agent and
a desiccating agent blended therewith.
FIG. 3 is an exaggerated, partial cross-sectional view of a solidified
plug formed from a polymer mixture having a channeling agent, a
desiccating agent, and a dimer agent blended therewith.
FIG. 4 is an exaggerated, partial cross-sectional view of a solidified
plug formed from a polymer mixture having a channeling agent, a
polarized desiccating agent, and a dimer agent blended therewith.
FIG. 5 is an exaggerated cross-sectional view of a portion of a
container having a desiccant entrained plug insert located in the
bottom of a container constructed from a polymer that acts as a
FIG. 6 is an exaggerated cross-sectional view of a portion of a
container having a desiccant entrained plug that has been comolded
into the bottom of a container that is constructed from a polymer
that acts as a moisture barrier.
FIG. 7 is an exaggerated cross-sectional view of a portion of a
container having a desiccant entrained liner insert located within
the interior of a container constructed from a polymer that acts
as a moisture barrier.
FIG. 8 is an exaggerated cross-sectional view of a portion of a
container having a desiccant entrained liner that has been comolded
at the interior of a container that is constructed from a polymer
that acts as a moisture barrier.
FIG. 9 is an exaggerated cross-sectional view of a desiccating
sheet or area located adjacent to a barrier sheet constructed from
a polymer that acts as a moisture barrier.
FIG. 10 is an exaggerated cross-sectional view of a desiccating
sheet or area that has been comolded at an interior of a barrier
sheet so that the products are integrally molded together and comprise
one unified laminate.
FIG. 11 is a schematic of the process for forming desiccant entrained
plugs, liners and sheets according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE PRESENT
As required, detailed embodiments of the present invention are
disclosed herein; however, it is to be understood that the disclosed
embodiments are merely exemplary of the invention that may be embodied
in various forms. The figures are not necessarily to scale, some
features may be exaggerated to show details of particular components.
Therefore, specific structural and functional details disclosed
herein are not to be interpreted as limiting, but merely as a basis
for the claims and as a representative basis for teaching one skilled
in the art to variously employ the present invention.
Certain terminology will be used in the following description for
convenience and reference only and should not be considered limiting.
For example, the words "rightwardly", "leftwardly",
"upwardly" and "downwardly" refer to directions
in the drawings to which reference is made. The words "inwardly"
and "outwardly" refer to directions toward and away from,
respectively, the geometric center of the structure being referred
to. This terminology includes these words, specifically mentioned
derivatives thereof, and words of similar import.
Furthermore, elements may be recited as being "coupled";
this terminology's use anticipates elements being connected together
in such a way that there may be other components interstitially
located between the specified elements, and that the elements may
be connected in fixed or movable relation, one to the other. Still
further, some structural relationships or orientations may be designated
with the word "substantially". In those cases, it is meant
that the relationship or orientation is as described, with allowances
for variations that do not effect the operation or cooperation of
the so described component or components. Referring to FIG. 1 of
the accompanying drawings, an insert constructed from a desiccant
entrained polymer 20 is illustrated. For purposes of this disclosure
of the present invention, the words "entrain" and "contain"
have been used interchangeably when referring to the inclusion of
a desiccating agent 30 in a polymer 25 matrix. The insert is in
the form of a plug 55 that may be deposited into a container body
60 thereby establishing a desiccating container 61. Referring to
FIG. 2 a cross-sectional view is shown of the plug 55 that has
been constructed from a polymer mixture 40 comprising a polymer
base 25 that has been blended with a desiccating agent 30 and a
channeling agent 35. In the illustration of FIG. 2 the mixture
has solidified so that veins or channels 45 have formed throughout
the polymeric mixture 40 to establish passages 47 throughout the
solidified plug 55. As may be appreciated in both FIGS. 1 and 2
the passages 47 terminate in channel openings 48 at an exterior
surface of the plug 55.
FIG. 3 illustrates a plug 55 similar in construction and makeup
to the plug 55 of FIG. 2 however, a dimer agent 50 has also been
added to the mixture 40. The dimer agent 50 enhances the compatibility
between the polymer 25 and the channeling agent 35. This enhanced
compatibility is facilitated by a lowered viscosity of the mixture
which promotes a more thorough blending of the two compounds 2535
which resists combination into a uniform solution. Upon solidification
of the mixture 40 that has had a dimer agent 50 added thereto, the
passages 47 which are formed therethrough have a greater dispersion
and a smaller porosity thereby establishing a greater density of
passages 47 throughout the plug 55. The channels or passages 47
are created to provide pathways through which moisture can travel
from the exterior of the solidified plug 55 to interior locations
where entrained desiccant 30 is bound. These passages 47 are required
because of the hydrophobic characteristics of the polymer 25 which
resist moisture permeability therethrough and therefore acts as
a moisture barrier. For this reason, the polymer 25 itself is referred
to as a moisture barrier substance within which a desiccant 30 may
be entrained. To expose the desiccant 30 entrained within the interior
of the polymer 25 however, the channels 47 are provided. Without
the passages 47 relatively small quantities of moisture would be
absorbed by the entrained desiccating agent 30. These small amounts
derive from the limited number of desiccant particles 30 that would
be exposed at the exterior surface of the formed body and the very
small amounts of moisture that would be able to pass through the
substantially moisture impermeable polymer 25. Because of these
characteristics, the polymer 25 is referred to as a moisture barrier
even though it may not be completely impermeable to moisture. In
the illustration of FIG. 3 the passages 47 have been enhanced by
the dimer agent 50 but the desiccating agent 30 is evenly distributed
throughout the mixture 40 matrix. As a result, at least portions
of the desiccating agent 30 will be entrained within the polymer
25 which resist transmission of moisture and therefore seals those
particles of desiccating agent 30 within the polymer 25 from moisture
FIG. 4 illustrates a solidified plug 55 wherein the desiccating
agent 30 has been selected so that it is polarized and therefore
attracted to the channeling agent 35. As a result, during the solidification
process, the desiccating agent 30 aggregates in the channeling agent
35 and becomes entrained therein in a concentration higher than
in the polymer 25. As a result, a greater percentage of the desiccating
agent 30 is entrained within the channeling agent 35 and therefore
placed in communication with moisture exterior to the plug 55 thereby
improving the plug's 55 moisture absorbing characteristics. In at
least one embodiment, the channeling agent 35 is selected so that
it has a property which encourages transmission of moisture thereacross.
The rate at which moisture is transmitted across the channeling
agent 35 is greater than the rate at which moisture may be transmitted
across the polymer 25. This tends to provide a ready supply of moisture,
when present, to the desiccating agent 30 entrained within the channeling
agent 35 and to that desiccating agent 30 that is entrained within
the polymer 25 but adjacent to and exposed to the channeling agent
35. Examples of channeling agents 35 having these characteristic
are EVOH and PVOH, each of which transmit moisture at a rate greater
than the polymer 25 and the desiccating agent 30. As a result, the
channeling agent 35 acts as a bridge between moisture exterior to
the plug 55 and the desiccating agent 30 entrained within the plug's
FIG. 5 illustrates a plug 55 which has been deposited into a container
body 60 thereby establishing a desiccating container 61. The container
body 60 has an interior surface 65 and is constructed substantially
from a moisture barrier polymer 25. In this manner, moisture is
resisted from being transmitted across a wall of the container 60
when the container 60 is closed. As may be seen in FIG. 5 the plug
55 has been press fit into a bottom location of the container 60.
It is contemplated that the plug 55 may be merely deposited in the
container 60 for loose containment therein, but it is preferable
coupled to the body of the container 60 in a manner that fixes the
plug 55 to the container 60. The couple between the plug 55 and
the container body 60 is intended to prevent the dislocation and
relative movement of the plug 55 thereabout. This connection may
be accomplished by a snug press fit between the plug 55 and the
interior surface 65 of the body 60 or it may be mechanically connected
in such manners as adhesives, prongs, lips or ridges that extend
about the plug 55 to hold the plug 55 in place. In yet another embodiment,
it is contemplated that the container body 60 may be molded about
the plug 55 so that during the curing process of the container body
60 the body 60 shrinks about the plug 55 thereby causing a shrink-fit
to be established between the two components. This type of couplement
may also be accomplished in a comolding process or sequential molding
process wish the same results achieved because the desiccant entrained
plug 55 will have less shrinkage than the polymer 25 comprised container
FIG. 6 illustrates a desiccating container 61 having a desiccant
entrained plug 55 located at a bottom location of the container
60 similar to the configuration illustrated in FIG. 5 but the plug
55 and container body 60 are comolded so that a unified body 61
is formed with a less distinct interface between the plug 55 and
body 60 components.
FIGS. 7 and 8 illustrate concepts similar to those of FIGS. 5 and
6 however the proportions of the plug 55 have been extended so
that a liner 70 is formed which covers a greater portion of the
interior surface 65 of the desiccating container 61. The liner 70
is not localized in the bottom portion of the container body 60
but has walls which extend upwardly and cover portions of the walls
of the container 61. Uke the plug 55 the liner 70 may be separately
molded and subsequently combined with the container body 60 or it
may be comold therewith into the unified body illustrated in FIG.
FIGS. 9 and 10 illustrate an embodiment of the invention in which
a desiccating sheet 75 is created for combination with a barrier
sheet 80. The characteristics of the sheets are similar to those
described with respect to the plug 55 and liner 70 and container
body 60. That is, FIG. 9 illustrates an embodiment in which the
two sheets 7580 are separately molded, and later combined to form
a packaging wrap having desiccating characteristics at an interior
surface and moisture resistant characteristics at an exterior surface.
FIG. 10 illustrates a comolded process wherein an interface between
the desiccating sheet 75 and the barrier sheet 80 is less distinct
than in the embodiment of FIG. 9. This product can be produced by
a thermal forming process. In such a process, the polymer layer
is melted and partially formed into a sheet with the desiccating
agent 30 being deposited on top of that layer just prior to being
pressed or extruded through a slit-like opening in the thermal forming
machine. It is contemplated that the separate sheets 7580 of FIG.
9 may be joined together with an adhesive or other suitable means
to form a laminate from the plurality of sheets 7580. Alternatively,
the sheeting 7580 may be manufactured from a thermal extrusion
process whereby both sheets 7580 are manufactured at the same time
and effectively comolded together to form the embodiment illustrated
in FIG. 10.
FIG. 11 provides a schematic illustration of the process by which
the several embodiments of a desiccating container 61 may be formed.
The details of those processes have been described herein with respect
to the several varying structures that may be established from the
basic mixture or combination 40 of a polymer base 25 with a desiccating
agent 30 and a channeling agent 35. As disclosed, a dimer agent
50 may be optionally provided to enhance the channeling characteristics
of the mixture 40 during the solidification process.
In view of the descriptions provided above relevant to possible
embodiments of the present invention and the included figures illustrating
the same, the following embodiments are also disclosed. In one embodiment,
the present invention includes a process for producing a moisture
absorbing desiccant entrained polymer 20. A polymer 25 is caused
to assume a molten state, typically by applying heat and melting
the polymer. To achieve certain results in the hardened end product,
such as rigidity and durability, the polymer 25 normally acts as
a moisture barrier in a solidified state, both before and after
melting. A desiccating agent 30 is blended into the polymer 25 so
that the desiccating agent 30 is distributed within the polymer
25. A channeling agent 35 is also blended into the polymer 25 so
that it is distributed within the polymer 25. Together, the polymer
25 desiccating agent 30 and channeling agent 35 create a blended
mixture 40. The mixture 40 is solidified so that the channeling
agent 35 forms passages in the mixture 40 through which moisture
is communicable to desiccating agent 30 that is entrained within
the mixture 40.
The channeling agent 35 separates from the polymer 25 into veins
or channels 45 that extend through the polymer 25. When hardened
into a rigid plastic body, these channels 45 form the moisture communicating
passages 47 throughout the plastic body.
A dimer agent 50 may be optionally blended into the mixture 40
to increase the mixing compatibility of the polymer 25 and the channeling
agent 35 thereby increasing the dispersion of the passages 47 within
the solidified mixture 40. This occurs because the viscosity of
the mixture 40 is lowered and the polymer 25 and channeling agent
35 more thoroughly mix. This causes the passages 47 that are formed
to have smaller pore sized and to be more densely dispersed throughout
the solidified body of the mixture 40.
The polymer 25 is a moisture barrier that more greatly resists
diffusion of moisture thereacross than does the desiccating agent
30 or the channeling agent 35; it is not necessary that the polymer
25 be absolutely moisture impermeable, however.
The channeling agent 35 facilitates diffusion of moisture therethrough
at a rate greater than the desiccating agent 30 or the polymer 25.
The desiccating agent 30 has a greater moisture absorbing capacity
by weight than the channeling agent 35 or the polymer 25.
The desiccating agent 30 has a greater attraction for the channeling
agent 35 than for the polymer 25. As a result, upon solidification
of the mixture 40 a greater concentration of desiccating agent
30 forms in the channeling agent 35 than in the polymer 25.
The channeling agent 35 acts as a moisture bridge between passage
openings 48 at an exterior surface of the mixture 40 and desiccating
agent 30 entrained within the mixture 40.
The polymer 25 may be selected from a group that includes, but
is not limited to polypropylene and polyethylene.
The channeling agent 35 is selected from a group that includes,
but is not limited to ethylene-vinyl alcohol (EVOH) and polyvinyl
The desiccating agent 30 is of the type that physically absorbs
moisture, is inert and non-water soluble.
In a further embodiment of the present invention, a plug 55 is
formed from the mixture 40 for inclusion within a container 60 that
is constructed from a moisture barrier substance.
In one embodiment, the plug 55 is deposited into a container 60
that is constructed from a moisture barrier substance. In this manner,
a desiccating container 61 is created.
The plug 55 may be coupled to an interior surface of the container
body 60 so that the plug 55 is fixed relative to the container 60.
Alternatively, a container 60 constructed from a moisture barrier
substance may be molded about the plug 55 so that at least a portion
of the plug 55 is exposed to an interior of the container 60.
A desiccating plug 55 made according to the present invention may
also be comolded with a container 60 that is constructed from a
moisture barrier substance so that at least a portion of the plug
55 is exposed to an interior of the container 60.
In another embodiment, a liner 70 may be formed from the mixture
40 and then be included within a container 60 constructed from a
moisture barrier substance. The liner 70 typically, but not necessarily,
has an exterior surface configured for mating engagement with an
interior surface 65 of the container 60.
The liner 70 may be pressed into mating engagement with the container
60 so that a desiccating container 61 is created wherein at least
a majority of the interior surface 65 of the container is covered
by the liner 70.
The liner 70 may be formed from the mixture 40 and then a container
60 constructed from a moisture barrier substance may be molded about
the liner 70 so that at least a portion of the liner 70 is exposed
to an interior of the container 60 and a majority of an interior
surface 65 of the container 60 is covered by the liner 70.
Alternatively, the liner 70 and container body 60 may be comolded
together into a unified body.
In an alternative embodiment of the present invention, a process
for producing a moisture absorbing desiccant entrained polymer sheet
75 is provided. A desiccating agent 30 is blended into the polymer
25 so that the desiccating agent 30 is distributed within the polymer
25. A channeling agent 35 is also blended into the polymer 25 so
that the channeling agent 35 is distributed within the polymer 25
thereby creating a blended mixture 40 of polymer 25 desiccant 30
and channeling agent 35. The mixture 40 is then formed into a desiccating
sheet 75 so that veins 45 of channeling agent 35 form passages 47
in the sheet 75 through which moisture is communicable to desiccating
agent 30 entrained within the mixture 40.
The desiccating sheet 75 is combined with a barrier sheet 80 that
is constructed of a moisture barrier substance for use as a packaging
The sheets 7580 may be laminated by thermal extrusion.
In yet another embodiment of the invention, a process for making
a moisture absorbing insert for a container 60 is provided. The
process includes blending a desiccating agent 30 and a channeling
agent 35 into a polymer 25 so that a mixture 40 is formed. The mixture
40 is then solidified so that the channeling agent 35 forms passages
47 in the mixture 40 through which moisture is communicable to the
desiccating agent 30 entrained within the mixture 40.
A dimer agent 50 may optionally be added to the mixture 40 to increase
the mixing compatibility of the polymer 25 and the channeling agent
35 thereby increasing the dispersion of the passages 47 within the
solidified mixture 40.
In still another embodiment of the present invention, a method
for making a desiccating container 61 is provided. The method includes
forming a container 60 from substantially moisture impermeable material
so that a moisture barrier is created between an interior and exterior
of the container. An insert is formed from desiccant bearing material.
The insert has an exterior surface that is configured for mating
engagement with at least a portion of an interior surface 65 of
the container 60. The insert is installed into the interior of the
container 60 so that at least a portion of the exterior surface
of the insert abuttingly engages the interior surface 65 of the
container 60. The engagement fixes the insert relative to the container
60 and resists disengagement of the insert from the container 60.
The insert is channeled with passages 47 so that desiccant 30 within
an interior of the insert is exposed to the interior of the container
60 for absorbing moisture.
The insert is pressed into the interior of the container 60 with
sufficient force that the insert fits tightly within the container
60 thereby resisting disengagement therefrom.
The insert is sized and shaped so that the insert fits snugly into
a receiving location within the interior of the container for retention
at the receiving location.
In another embodiment, the insert is sized and shaped into a plug
55 chat fits snugly into a receiving location at a bottom portion
of the interior of the container 60 for retention at the receiving
Alternatively, the insert is configured into a liner 70 having
an exterior surface that conforms to the interior surface 65 of
the container 60 so that a majority of the liner's 70 exterior surface
is in abutting engagement with the container's 60 interior surface
The container 60 and the liner 70 are similarly configured so that
the interior 65 of the container 60 and the exterior of the liner
70 fit snugly together so that disengagement of the liner 70 from
the container 60 is resisted.
The container 60 may be molded from a plastic that is substantially
moisture impermeable and therefore resists the transmission of moisture
across the boundary of the container 60 between its exterior and
its interior. Also, the liner 70 may be molded from a desiccant
entrained plastic 20 capable of absorbing and retaining moisture
A releasable cap means may also be provided for closing the container
60. In this way, the liner 70 is substantially sealed within the
capped container 60 by installing the cap means upon the container.
Moisture held within the interior volume of the container 60 may
then be removed by the desiccant 30.
A product may be stored in the substantially moisture free interior
of the lined container 61 by enclosing the product therein.
In yet another embodiment, a method for making a desiccating container
61 is provided. A container is formed from substantially moisture
impermeable material so that a moisture barrier is established between
an interior and exterior of the container 60. A substantially solid
tablet or plug 55 is formed from desiccant bearing material 20
the tablet 55 being suitably sized to fit within the interior of
the container 60. The tablet 55 is then deposited into the interior
of the container 60 thereby establishing a means for desiccating
the interior of the container 60 when the container 60 is closed
about the tablet 55.
In another embodiment of the present invention, a method for making
desiccating packaging is provided. An outer skin, sheet, or layer
80 is formed from a substantially moisture impermeable sheet of
material so that a moisture barrier is created between opposite
sides of the skin. An inner skin, sheet, or layer 75 is formed from
desiccant bearing material 20 at one side of the outer skin 80.
A desiccating package is formed about a product or item by sealing
the product or item within the outer moisture impermeable skin 80
and with the inner desiccating skin 75 located adjacent to the product.
A desiccating laminate may be formed by suction vacuum molding
the outer skin 80 and the inner skin 75 together to form desiccating
In one embodiment of the present invention, a desiccating enclosure
61 is provided. The enclosure includes a container 60 formed from
substantially moisture impermeable material so that a moisture barrier
is created between an interior and exterior of the container 60.
A liner 70 is formed from desiccant bearing material 20 so that
the liner 70 has an exterior surface configured for mating engagement
with at least a portion of an interior surface 65 of the container
60. The liner 70 is inserted into the interior of the container
60 so that at least a portion of the exterior surface of the liner
abuttingly engages the interior surface 65 of the container 60.
The engagement fixes the liner 70 relative to the container 60 and
resists disengagement of the liner 70 from the container 60.
In another embodiment of the present invention, a desiccating insert
for a closeable container 60 includes a desiccating insert configured
for installation into a closable container 60. The insert is constructed
from thermoplastic entrained 25 with a desiccating agent 30 that
is distributed substantially evenly throughout an interior of the
insert. The insert has passages 47 extending from its exterior surface
into its interior. Moisture is passable through the channels or
passages 47 thereby exposing portions of the desiccating agent 30
located within the interior of the insert to moisture located exteriorly
to the insert for absorbing and retaining that exteriorly located
Desiccant entrained plastic structures, and their constituent compounds
have been described herein. As previously stated, detailed embodiments
of the present invention are disclosed herein; however, it is to
be understood that the disclosed embodiments are merely exemplary
of the invention that may be embodied in various forms. It will
be appreciated that many modifications and other variations that
will be appreciated by those skilled in the art are within the intended
scope of this invention as claimed below without departing from
the teachings, spirit and intended scope of the invention.