A desiccant system and a method for producing the same wherein
a container is provided with a desiccant sheet that is trapped within
the container and a water vapor impermeable cover for the container
making a water impermeable seal thereto. The sheet may have a first
substrate, and optionally, a second substrate, and desiccant particles
adhered to the first substrate or trapped between the first substrate
and the second substrate. A binder material may fuse the desiccant
particles to one another and to the substrates. The sheet may be
trapped within the bottle due to its tendency to unfurl to a flat
condition, or it may be adhered to an inner surface of the bottle.
What is claimed is:
1. A desiccant system comprising: a bottle having sidewalls thereof;
and a desiccant sheet having characteristics that cause said desiccant
sheet to unfurl within said bottle to a substantially flat configuration
wherein said desiccant sheet comprises: a first substrate that faces
contents to be placed in said bottle, the first substrate being
water vapor permeable; and a composite layer formed on the first
substrate, the composite layer including desiccant particles and
binder particles having an average particle size of about 10 to
about 30 microns, a portion of the binder particles adhering the
desiccant particles to one another and a portion of the binder particles
adhering the desiccant particles to the first substrate.
2. A desiccant system of claim 1 wherein said desiccant sheet comprises
silica particles having an average particle size of about 5 to about
3. A desiccant system of claim 1 wherein the desiccant particles
are present in said desiccant sheet at about 70% to about 90% by
weight of the composite.
4. A desiccant system of claim 1 wherein said desiccant sheet comprises
about 17% by weight binder particles.
5. A desiccant system of claim 1 wherein the composite is applied
at a density of about 300 g/m.sup.2.
6. A desiccant system of claim 1 wherein the first substrate comprises
a bi-component fiber web wherein the particles of the composite
layer are trapped within the bi-component fiber web.
7. A desiccant system of claim 1 wherein said desiccant sheet further
includes a second substrate and wherein the composite layer is formed
between the first and second substrate such that the second substrate
is in contact with the sidewalls of said bottle when said desiccant
sheet is unfurled within said bottle.
8. A desiccant system of claim 1 further including an adhesive
for securing said desiccant sheet within said bottle.
9. A desiccant system of claim 1 wherein edges of said desiccant
sheet are sealed by one of application of a sealant, supplemental
heating, and welding.
10. A desiccant system of claim 1 further including a cap or cover
to said bottle.
11. A desiccant system of claim 1 wherein said desiccant sheet
covers a significant portion of an interior of said bottle.
12. A desiccant system of claim 11 wherein said desiccant sheet
cushions contents of said bottle.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to desiccant systems. More particularly,
it relates to systems wherein the contents of a bottle, such as,
for example, pharmaceuticals (pills, tablets, capsules) are stored
in a low humidity environment.
2. Prior Art
There are a variety of ways to package desiccant materials used
to provide humidity control in bottles or enclosures such as those
used to store moisture-sensitive scientific instruments, specialty
chemicals, or pharmaceuticals. Generally, these consist of packets
that are filled with desiccant materials, canisters containing such
materials, or solids such as tablets or cylinders containing desiccant.
All of these approaches have respective disadvantages.
First, desiccant packages take up space. Thus, they reduce the
volume of material that can be stored within an enclosure. In some
cases, this may not be a major disadvantage. However, once a sealed
enclosure is opened, these desiccant packs can fall out and are
often lost. In fact, in some cases, individuals not aware of their
purpose tend to discard these packs. Thus, the contents are no longer
safeguarded against excessive moisture. In those cases where the
desiccant package is retained, it is often removed from the package
and exposed to dust, atmospheric moisture and other forms of contamination
before being returned to the package. Thus, unwanted bacterial contamination
may take place and the contents may no longer be appropriate for
If small desiccant cylinders are permitted to remain in a bottle
containing, for example pills, there is a chance of them being accidentally
ingested. While this in itself may not be dangerous, the failure
of someone to take a critically required medication, because that
person believes it has already been taken, may be extremely dangerous.
Desiccant canisters, while avoiding some of these problems, are
expensive to manufacture. The costs involved in making an entire
enclosure of a desiccant material are inherently significant.
Accordingly, there is a need for a system for placing and retaining
a desiccant in a container so as to overcome the disadvantages inherent
in existing desiccant systems.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a desiccant
and container system wherein the usable space available in the container
is not significantly reduced by the presence of the desiccant.
It is another object of the invention to provide a desiccant and
container system wherein the desiccant material is not easily lost
It is a still another object of the invention to provide a desiccant
container system that is easy to manufacture and low in cost.
In accordance with the invention, a sheet of desiccant material
is placed in an enclosure or bottle which requires humidity control.
The sheet may be sized and shaped so that it can be rolled up, placed
through the neck of the bottle, and allowed to expand inside the
bottle against the walls thereof. Accordingly, the sheet is then
effectively secured in place within the bottle against its walls.
It cannot easily be removed from the bottle and lost. Further, it
is not subject to exposure to atmospheric moisture, contaminants
and bacteria that may be found outside the bottle. Finally, it is
not subject to being accidentally ingested.
As used herein, the term "bottle" refers to a bottle,
enclosure, or other container, and may include jars, pill bottles,
or other similar structures in which moisture sensitive products
may be packaged.
The present invention is also directed to a method for producing
the container and desiccant system described above. In accordance
with the method, a desiccant sheet of appropriate size and shape
is rolled into a cylindrical configuration, placed through the neck
of the bottle into the interior of the bottle, and then allowed
to expand against the walls of the bottle, thus securing the sheet
within the bottle. If the opening or neck of the bottle is not smaller
in size than the remainder thereof, a small amount of an adhesive
may be used to secure the sheet in place.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing aspects and other features of the present invention
are explained in the following description, taken in connection
with the accompanying drawings, wherein:
FIG. 1 is a cross section of a desiccant sheet that may be used
in the present invention.
FIG. 2 is a perspective view of a bottle having a desiccant sheet
in accordance with the invention, inserted there.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 there is shown a cross sectional view of a
desiccant sheet 10 which may be used in the present invention. Although
the present invention will be described with reference to the single
embodiment shown in the drawings, it should be understood that the
present invention can be embodied in many alternate forms of embodiments.
In addition, any suitable size, shape or type of elements or materials
could be used.
In FIG. 1 a desiccant sheet 10 includes a first substrate 12 and
a second substrate 14. Substrates 12 and 14 have, disposed between
them a composite layer 16 including particles of a desiccant material,
such as for example, silica gel, activated alumina, zeolite or similar
material, and a suitable binder material for binding at least a
portion of the desiccant particles to each other, and at least a
portion of the desiccant particles to one of the substrates 12 and
14. Substrates 12 and 14 are preferably non-woven fabrics such as
non-woven polypropylene available from Polymer Group, Inc. (PGI)
of North Charleston, S.C., USA, and having a weight of 0.5 to 1.5
ounces per square yard. For example, substrates 12 and 14 may have
weights of 1.5 and 1.0 ounces per square yard, respectively. Alternatively,
substrates 12 and 14 may have weights of 1.0 and 0.6 ounces per
square yard, respectively. It is important that at least one of
the substrates 12 and 14 be water vapor permeable so that the desiccant
particles can absorb water vapor when sheet 10 is placed in the
enclosure or bottle.
Sheet 10 may be formed by the process described in detail in U.S.
Pat. Nos. 5792513 and 6077588 which are incorporated by reference
in their entirety, as if fully set forth herein. Materials of this
general nature are sold under the trademark PLEKX.RTM., by KX Industries,
L.P. of Orange, Conn., USA, the assignee of these patents.
Although shown in this embodiment as a material with two substrates,
it will be understood that the medium may be formed with a composite
layer of desiccant particles and binder upon a single substrate,
in accordance with the process of the above mentioned patent. In
addition, multiple layer versions are possible with alternating
layers of water vapor permeable substrates and desiccants. A thin
sheet 10 is preferred.
The binder used to hold the structure of FIG. 1 together can be
low-density polyethylene ("LDPE") binder particles, such
as grade FN510 supplied by Equistar Chemicals, L.P. of Tuscola,
Ill., USA, and manufactured and sold under the trade name Microethane.RTM..
These LDPE particles are primarily in the range of 10 to 30 microns
in diameter, with some portion of the size distribution being outside
this range. This material can be combined with an additive of approximately
one half of one percent (0.5%) of synthetic amorphous precipitated
silicon dioxide, specifically a synthetic amorphous silicon dioxide
hydrate sold under the name Sipernate.RTM. 22LS, supplied by Degussa-Huls,
through its Degussa Corporation Pigment Group of Richfield Park,
The silica gel particles have an average size of 149 microns, with
an approximately normal distribution about that size. The mixture
of silica gel particles and binder may be applied at a density of
300 grams per square meter, with the binder comprising approximately
17% by weight of the mixture.
While silica gel particles are preferred, other desiccant particles
may be used. In particular, such particles include activated alumina,
zeolite, calcium sulfate, calcium oxide and other particles that
are hydrophilic and can provide a desiccant action for the contents
of a container in which sheet 10 is placed. The particles may have
a size in the range of 5 to 5000 microns.
Desiccant sheet 10 can be produced by other means. Hydrophilic
particles may be adhered to an appropriate substrate with an adhesive.
The particles may also be trapped in a bi-component fiber web. Other
methods well known in the art may be used to produce desiccant sheet
Referring to FIG. 2 a bottle 20 receives as a liner, a sheet
10 in accordance with FIG. 1. Sheet 10 is sized and shaped, such
as by slitting and sheeting, to a configuration that allows it to
be rolled up into a generally cylindrical shape, placed through
the mouth 21 of bottle 20 and then released therein to expand so
as to become a liner of at least a portion of bottle 20. Preferably,
sheet 10 is thus disposed in bottle 20 at a position separate and
apart from any cap or closure that may be applied to bottle 20.
Sheet 10 preferably has characteristics that causes it to unfurl
towards its normally flat configuration, and thus will become lodged
against the wall of bottle 20. In a bottle 20 where neck 22 is smaller
in diameter than the remainder of bottle 20 sheet 10 will be trapped
within bottle 20. While it is possible to remove sheet 10 from bottle
20 depending upon the size of neck 22 it may be difficult, require
significant manual dexterity or may require the use of special tools.
In general, sheet 10 will remain trapped in bottle 20 and will not
be lost or subject to contamination by dirt or bacteria. Accidental
ingestion is not possible.
In cases where the mouth 21 and neck 22 of a bottle are large and
of the same, or nearly the same, diameter as bottle 20 sheet 10
may be secured within bottle 20 by adhesive bonding thereto. Specifically,
a small amount of a non-toxic adhesive 25 (shown, but not required
in the embodiment of FIG. 2), may be applied to the one of substrates
12 or 14 that will come in contact with the inner surface of bottle
20. The adhesive is then allowed to set and the sheet is affixed
within bottle 20.
As noted above, a sheet 10 having a single substrate and a composite
layer with desiccant particles and binder particles fused thereto
may also be used. If such layer is used, it is generally preferable
that the single substrate be positioned so that it is facing, and
in contact with, the contents of bottle 20. In this case, the single
substrate must be water-vapor permeable. If a sheet having two substrates
is used, at least one must be water vapor permeable and should face
the contents when in place.
In use, bottle 20 is then filled with its customary contents which
may include pharmaceuticals. A suitable humidity tight cap or cover
26 of the snap-on or screw-on variety, is then placed over the receiving
end of mouth 21 to seal bottle 20. Suitable tamper resistant packaging
is then used to package bottle 20 in a manner well known in the
When bottle 20 is used by the ultimate user or consumer, the tamper-proof
packaging is removed and bottle 20 is opened by removing cap or
cover 26 from mouth 21. Periodically, a portion of the contents
is removed for use. After such removal, the bottle is again resealed
by replacing cap or cover 26 over mouth 21.
It will be understood that sheet 10 will remain within bottle 20
during all such use. Sheet 10 will not be subject to loss, contamination
by dirt or bacteria, or accidental ingestion by the consumer. Thus,
the present invention provides an inexpensive and virtually foolproof
way for keeping the contents generally free from moisture for the
life of the product placed in bottle 20 or at least until the desiccant
sheet becomes saturated. To the extent that sheet 10 covers a significant
portion of the interior of bottle 20 it will also provide a cushioning
effect for the contents thereof, tending to, for example, make the
fragmenting of pills or tablets less likely if bottle 20 undergoes
rough handling during shipping or use.
It will be understood that the present invention may be implemented
in other ways. For example, it may be possible to mold a plastic
bottle around a cylindrical sheet 10 or alternatively sheet 10
may be inserted into the mold that produces bottle 20. In either
case, a structure similar to that described in detail herein, and
having exactly the same functionality and advantages will be produced.
In certain cases, it may be advantageous to seal the edges of sheet
10 in any one of a variety of ways well known in the art, such as
for example, by application of a sealant around the periphery, or
by supplemental heating or welding (including ultrasonic welding)
of the exposed edge thereof. This will assure that desiccant particles
do not break away from sheet 10 so as to mix with the contents of
It should be understood that the foregoing description is only
illustrative of the invention. Various alternatives and modifications
can be devised by those skilled in the art without departing from
the invention. Accordingly, the present invention is intended to
embrace all such alternatives, modifications, and variances which
fall within the scope of the appended claims.