Note: Descriptions are shown in the official language in which they were submitted.
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HUMIDIFYING CAPSULE FOR USE WITH TOBACCO PRODUCTS
BACKGROUND OF THE INVENTION
The present invention relates to a humidifying capsule for use with tobacco
products.
The tobacco in products such as cigarettes, cigars and loose tobacco for pipe
smoking or
roll-your-own cigarettes is prone to drying out both during the pre-use
storage period and
particularly after the product packaging has been opened. This is undesirable,
since tobacco
becomes less palatable as it dries.
Expensive cigars are generally stored in specially designed humidors
specifically to address
this problem by keeping the cigars at a desired level of humidity to prevent
drying. A more
rudimentary approach is often used by consumers of loose tobacco; a piece of
apple or
potato peel placed in the tobacco pouch or tin can help to keep the tobacco
moist or can
re-moisten tobacco that has become too dry. However, this method may not be
considered
hygienic, and may taint the tobacco with unwanted scents or flavours.
Various humidification devices and moisture dispensers have therefore been
proposed for
use with tobacco products, in particular for use in tobacco pouches and tins
and cigarette
packs. Typically, the devices comprise a source of moisture that can emit
water vapour
which is surrounded by a permeable enclosure such as a housing, casing, layer
or pouch
which keeps the moisture source separate from the tobacco but allows the water
vapour to
be transmitted to the tobacco. The moisture source is often some form of water-
absorbent
medium such as cotton wool, blotting paper, sponge, florists' foam, or
polyacrylamide gel
or crystals, which is soaked with water or salt solution. The permeable
enclosure may be
rigid or flexible, and may be made permeable by the provision of perforations
or apertures
therein, or may be an inherently permeable membrane material. Examples
include: a
plastics or metal case with a slotted front face (GB 2,265,295); a pouch of
porous crepe
rubber (GB 741,475); a cylindrical tube with pin-hole perforations (GB
567,141); a flat
metal sheath with open sides for sandwiching a sheet of blotting paper (GB
308,127); a
spunbonded web of polypropylene filaments (EP 348,840); a plastic tube with
removable
end caps (US 5,957,380); a mesh screen (US 5,957,277); a container made from
propionate
(US 5,829,452); spherical capsules made from polyethylene, amorphous organic
resin and
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wax and having microscopic pores (US 3,801,011); tissue paper and fine-meshed
cloth (US
1,871,419); textile or non-woven material (WO 02/12089); a water-impermeable
sleeve
with ends closed by cotton wool (DE 20 2005 008 520); and a stainless steel
mesh tube
(DE 20 2005 010 286). Further example can be found in GB 2,345,431, GB
1,369,992, GB
119,489, EP 531,075, EP 363,194, US 1,874,989, DE 4000143, and FR 2,619,289.
Some
devices are incorporated into tobacco packages, while others are independent
devices that
can be inserted into a tobacco product container. Some devices include an
outer non-
permeable enclosure to prevent moisture loss before the device is used. For
example, US
5,957,380 describes a plastic tube containing a porous material holding a
humidiftcation
/0 solution of glycol, water and saturated salt, the tube having end caps
which are removed to
let water vapour out when the device is placed in a cigar container. US
3,801,011 describes
a humidity control device comprising a sheet-like carrier such as an adhesive
tape which
carries a layer of water-containing capsules having vapour-transmissive walls,
and which is
supplied in a sealed plastic bag.
Many of these examples are intended for re-use, in that the user is able to
hydrate the
water-absorbent medium before first use and many subsequent uses. Such devices
are
generally bulky and awkward, and comprise several parts to give the user
access to the
water-absorbent medium. Thus production of these devices can be complex and
expensive.
On the other hand, devices that are sealed and intended for only one use tend
to be made
from relatively delicate membrane materials which are at risk of puncture or
bursting.
SUMMARY OF THE INVENTION
Accordingly, a first aspect of the present invention is directed to a
humidifter for use with
tobacco products comprising: a closed capsule fabricated at least partially
from material
comprising a thermo-mechanically expanded polymer membrane having micropores
that
render the material permeable to moisturising vapour; and a source of
moisturising vapour
encapsulated within the closed capsule.
This attractively simple structure, in part made possible by the use of thermo-
mechanically
expanded polymer membranes, allows a tobacco humidifier to be provided very
easily. The
membranes are porous microstructured materials that are permeable to water
vapour and
impermeable to liquid water and which are particularly well-adapted for use as
a membrane
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to encapsulate a source of moisturising vapour in a humidifler. Among their
many useful
properties is the ability to tailor the pore structure during manufacture, so
that the rate at
which vapour can be released is selectable. Also, they are tough and strong so
a capsule
made from these membranes are unlikely to become damaged and spill liquid over
the
tobacco products is the materials are inert, so do not interact with the
tobacco. Further,
they can be readily made into a wide range of capsule shapes and sizes.
The polymer may be polytetrafluoroethylene, polybutylene terephthalate, or
polyethylene
oxide, for example. Other polymers are not excluded, however.
The source of moisturising vapour may be a volume of liquid water or,
alternatively, may
be water absorbed in a water-absorbing medium contained within the closed
capsule. This
gives a large choice of humidifier compositions, which can be selected
according to factors
such as cost, ease of manufacture, and control over vapour release. Hence the
design is
very flexible. Liquid water will likely be the least expensive way of
providing a source of
moisturising vapour for vapour release. However, a variety of water-absorbing
media offer
alternatives, including the use of one or more of polyacrylamide granules, an
alginate,
microcrystalline cellulose, ispaghula husk, saturated silica gel, rice, a
starch gel, a pectin,
natural sponge, synthetic sponge, a sepeolite, bentonite or other clay
material, gelatin, agar
agar, and a modified cellulosic gum. Also, the moisture source need not be
water; other
liquids suitable for moisturising tobacco may also be used.
In some embodiments, the closed capsule may be wholly fabricated from the
material
comprising thermo-mechanically expanded polymer membrane. This minimises the
component materials of the humidifier, and allows many shapes of capsule to be
readily
provided. For example, the capsule may have a corrugated or folded surface.
Alternatively,
the capsule may have a shape comprising a plurality of fingers radiating from
a central core
region. More generally, the capsule may have a shape intended to maximise its
surface area
for a given volume. The rate of vapour release depends on the area through
which the
vapour can escape the capsule, so a larger area for a given volume will
decrease the time in
which the available moisture can be released, giving a faster moisture
rejuvenation for the
tobacco.
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In other embodiments, the capsule comprises a moulded plastic tray that is
substantially
impermeable to moisturising vapour, and a layer of material comprising a
thermo-
mechanically expanded polymer membrane sealed to the moulded plastic tray to
close it.
This configuration exploits the desirable properties of the membranes for
vapour release
while offering an alternative construction to bonding or stitching together
several pieces of
membrane material
The hurriidifier may further comprise one or more water-soluble flavorants,
fragrances or
additives dissolved in the encapsulated source of moisturising vapour. A
smoker can
/0 thereby customise his tobacco by adding a fragrance or other characteristic
of his choice in
a very simple manner.
Also, the humidifier may further comprise a removable outer layer that is
substantially
impermeable to the passage of water vapour, the outer wrapper disposed over
the material
comprising a thermo-mechanically expanded polymer membrane and intended to be
removed before use of the humidifier. This keeps the moisture inside the
capsule until the
humidifier is needed, so that the humidifier can be supplied as a separately
packaged item
for use at any required time with any tobacco product that needs moisturising.
The removable outer layer may completely enclose the closed capsule, for
example as a bag,
envelope or sachet inside which the capsule is sealed.
Optionally, the humidifier may further comprise a visual humidity indicator on
an exterior
surface of the removable outer layer. If the hurriidifier is kept with the
tobacco product, the
smoker can use the indicator to determine when a release of moisturising
vapour would be
beneficial.
The hurriidifier may be incorporated into a package for tobacco products. A
second aspect
of the present invention is directed to a package for tobacco products
comprising a
humidifier according to the first aspect. The hurriidifier may be disposed on
an interior
surface of the package, for example, or may be provided loose inside the
package.
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A third aspect of the present invention is directed to a package for tobacco
products
containing one or more tobacco products and a humidifier according to the
first aspect.
The humidifter may be disposed on an interior surface of the package. The
package
may be a container for cigarettes, cigars or cigarillos, or a receptacle for
loose tobacco, such
as a pouch or a tin.
A fourth aspect of the present invention is directed to a method of
fabricating a humidifier
for use with tobacco products, the method comprising: forming a closed capsule
at least
partially from material comprising a thermo-mechanically expanded polymer
membrane
/0 having micropores that render the material permeable to moisturising
vapour; and injecting
a liquid source of moisturising vapour into the closed capsule.
The method may further comprise placing inside the capsule a liquid-absorbing
medium
before the capsule is closed. The liquid-absorbing medium may be one or more
of
polyacrylamide granules, an alginate, microcrystalline cellulose, ispaghula
husk, saturated
silica gel, rice, a starch gel, a pectin, natural sponge, synthetic sponge, a
sepeolite, bentonite
or other clay material, gelatin, agar agar, and a modified cellulosic gum.
The liquid source of moisturising vapour may be liquid water.
A fifth aspect of the present invention is directed to a method of fabricating
a humidifier
for use with tobacco products, the method comprising: forming a partially
assembled
capsule at least partly from material comprising a thermo-mechanically
expanded polymer
membrane having micropores that render the material permeable to moisturising
vapour;
forming a block of frozen water; placing the block of frozen water inside the
partially
assembled capsule; and sealing the partially assembled capsule around the
frozen water to
form a closed capsule encapsulating the frozen water. This approach avoids any
drawbacks
that may be associated with using liquid water in the production process. The
frozen water
may be contained within a water-absorbing medium such as one or more of
polyacrylamide
granules, an alginate, microcrystalline cellulose, ispaghula husk, saturated
silica gel, rice, a
starch gel, a pectin, natural sponge, synthetic sponge, a sepeolite, bentonite
or other clay
material, gelatin, agar agar, and a modified cellulosic gum.
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BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention and to shoxv how the same may be
carried into
effect reference is now made by way of example to the accompanying drawings in
which:
Figure 1 shows a cross-sectional view of a humidifier according to an
embodiment of the
presentinvention;
Figure 2 shows a cross-sectional view of a humidifier according to a further
embodiment of
the invention;
Figure 3 shoxvs a cross-sectional view of a humidifier according to a yet
Curther embodiment
of the invention;
Figure 4 shows a cross-sectional view of a humidifier'provided with an
impermeable outer
layer according to an embodiment of the invention;
Figure 5 shows a plan view of the humidifier of Figure 4;
Figure 6 shows a plan vie-w of humidifier provided with an impermeable outer
layer
according to an alternative embodiment;
Figures 7, 8 and 9 show examples of tobacco product packaging incorporating
humidity
indicators according to embodiments of the invention;
Figure 10 shows a cross-sectional view of a humidifier according to another
embodiment;
Figure 11 illustrates an example method. of fabricating a humidifier according
to an
embodiment of the invention; and
,Figures 12A to 12E illustrate steps in an alternative method of fabricating a
humidifier
according to an embodiment of the invention.
DETAILED DESCRIPTION
The present invention proposes the use of thermo-mechanically expanded
amorphous-
locked polytetrafluoroethylene (referred to henceforth as ePTFE) as a porous
membrane
for a humidifier intended for use with tobacco products. This material is
often known by
trade names including GORE-TEX (RTM). The present invention recognises that
this
material is well-suited for use as a porous membrane for this particular
application.
A humidifying device requires a source.of moisture to be enclosed in an outer
layer or
casing, which layer needs to be permeable to water vapour given off by the
moisture source
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but impermeable to the passage of liquid water, which would make the tobacco
too wet,
and also ruin products like cigarettes and cigars.
ePTFE has the necessary properties of permeability to water vapour and
impermeability to
liquid water (hence its common use in "breathable" waterproof garments). In
addition, the
porous microstructure of ePTFE can be precisely controlled during manufacture
(by
controlling the temperature and rate of expansion). It contains many
microscopic pores
(micropores) which are too small for droplet of liquid water (or other liquids
that might be
used for moisturising tobacco) to pass through, but which transmit water
vapour (or
>0 vapour of another moisturising liquid). Therefore, for use in a humidifier,
the rate of water
vapour release can be controlled by selection of an ePTFE with a suitable pore
size and
density. Also, the material has the form of a flexible sheet material, so it
can be used to
manufacture humidifiers of any desired shape and size. Pieces of the membrane
can be
bonded by an adhesive or cement material. ePTFE bonds to itself very readily
because the
bonding agent can penetrate a significant distance into the pores which form a
large
network through the ePTFE, and after drying, hardening or curing of the
bonding agent,
the two joined pieces are locked together. Alternatively, the ePTFE can be
laminated with
layers of fabric (such as nylon, polyester or polypropylene, for example) to
create a fabric-
like material. This can be stitched together (with treatment of the seams to
improve
waterproofing if required). Reference to ePTFE or to a material comprising
ePTFE in the
present document includes both ePTFE alone and a laminated ePTFE fabric.
Also, ePTFE is a particularly strong, tough material. This arises from the
fabrication
process, in which the expansion of the material increases the strength of its
polymeric
matrix. For use in a humidifier, this is a valuable property because the
membrane of the
humidifier is highly resistance to puncture or bursting. Combined with the
ability to make
secure seams and joins between individual pieces of ePTFE, as described in the
preceding
paragraph, this allows robust humidifiers in a wide range of shapes to be
produced.
ePTFE further has a high level of chemical inertness and a resistance to
undesirable
physical changes over a wide range of temperatures. These are further
beneficial properties
for use with tobacco products, where any interaction between the tobacco and a
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humidifying element in contact or near-proximity is undesirable, both from a
health
perspective, and for maintaining the quality of the tobacco product.
A detailed description of ePTFE and its manufacture can be found in US
3,953,566,
"Process for producing porous products". The polymer is heated and stretched
to a
superthin layer, which causes the microscopic pores to form in the polymer
structure.
Control of the temperature and the rate and amount of stretching (expansion)
can control
the size and density of the pores, and hence also the permeability.
>0 Other polymers can also be made into membranes with micropores by a thermo-
mechanical expansion process, to give membranes similar to ePTFE and hence
also
suitable for use in the present invention. The present invention is therefore
directed to
materials comprising thermo-mechanically expanded polymer membranes in
general, where
the membranes have micropores that make the material porous or permeable to
moisturising water vapour, but not to liquid. As with ePTFE, the other
polymers may be
laminated to fabrics or used as the membrane alone. Other examples of suitable
polymers
are polybutylene terephthalate and polyethylene oxide, plus some other fluoro-
polymers.
Water is a particularly convenient moisture source for hydrating tobacco via
evaporation
from a humidifier, but according to the invention, other sources of moisture
that can be
retained by the polymer membrane until released in vapour form by evaporation
through
the micropores can also be used, if the moisture is suitable for moisturising
tobacco.
Notwithstanding the foregoing, for the sake of convenience and simplicity, the
following
description is presented in terms of ePTFE and water, but all embodiments can
be
implemented using other polymer membranes and other liquids.
According to the invention, a humidifter for use with tobacco products has the
form of a
closed pouch or capsule formed at least partially from ePTFE and fiIled with a
moisture-
releasing element that emits water vapour. In its simplest form, the moisture-
releasing
element comprises a reservoir of liquid water, which is encapsulated by the
ePTFE pouch.
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Figure 1 shows a schematic cross-sectional view of a humidifier according to a
first
embodiment. The humidifier 10 comprises a closed (sealed so as to be
impermeable to the
passage of liquid water) capsule or pouch 12 fabricated from ePTFE. For
example, two
similarly shaped sheets of ePTFE can be stitched or bonded together around
their edges to
make a closed water-tight compartment. Inside the capsule 12 is a moisture-
releasing
element 14 in the form of a volume of liquid water. The liquid water 14 slowly
evaporates
at room temperature in the known manner, and the resulting water vapour 16
passes
through the ePTFE into the surrounding environment, as indicated by the arrows
in the
Figure. Thus, if the surrounding environment includes tobacco product, the
tobacco is
>0 moisturised.
As an alternative to liquid water, the humidifier may comprise a moisture-
releasing element
14 in the form of any medium that is capable of absorbing, holding or
otherwise providing
a quantity or reservoir of water, and giving up the water as water vapour,
preferably at
room temperature. For example, a paper matrix incorporating polyacrylamide
granules may
be used. A further example of a suitable water absorbing medium is one or more
alginates.
These materials are linear copolymers produced by various brown algae
including seaweed
(such as giant kelp) and bacteria (such as Azotobacter species), which are
insoluble in water
but absorb water quickly. Thus, a quantity of alginate can be soaked with
water before
being enclosed in the capsule 12. Alginates are fully biocompatible and are
used in food
stuffs and medicines, so they are a particularly attractive option for use
with tobacco
products.
Further examples of suitable materials for making the moisture-releasing
element 14
include micro-crystalline cellulose, ispaghula husk, saturated silica gel,
rice, starch gels,
pectins, natural sponge, synthetic sponge and clay materials such as
sepeolite, bentonite or
the like, gelatin, agar agar, and modified cellulosic gums. Combinations of
these materials
may also be used. As in the previous examples, a portion of the relevant
material is soaked
with water before encapsulation in the ePTFE capsule 12.
However, the invention is not limited to these particular examples of water
absorbing
media for the moisture-releasing element. Any material which has the necessary
properties
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to allow it to absorb an adequate amount of water and then release the water
as water
vapour by evaporation can be used.
For either liquid water or water held in a water-absorbing material, the water
need not be
plain water. An aqueous salt solution may be used instead, which can give
control over the
evaporation by determining the humidity level of the surrounding environment
below
which the water vapour will be released. Other non-volatile liquid ingredients
such as
glycerol (glycerine), or propylene glycol, may alternatively be used, as these
also control
evaporation of the water.
Additionally or alternatively, the moisture-releasing element may also contain
one or more
water-soluble additives that can be carried through the ePTFE capsule by the
water vapour
and hence delivered to the tobacco. These may include flavourants and
fragrances. For
example, a moisture-releasing element containing menthol can be used to impart
a menthol
flavour and smell to the tobacco. Vanilla, coffee and other flavours may be
similarly
provided. In this way, the consumer has a mechanism for flavouring a tobacco
product
with a flavour of their choice.
A particular benefit to using ePTFE to encapsulate the water vapour source is
that it can be
easily made into capsules of a wide range of shapes and sizes, for example by
joining
individual pieces of ePTFE together to form a closed shape. In the context of
the present
invention, it is convenient to maximise the amount of water vapour releasable
from a given
capsule in a given time. This speeds up the humidifying process and also
allows a small and
hence more convenient capsule to be used. To achieve this, the ratio of the
surface area of
the capsule to its volume can be made large, or even maximised. Any shape that
has a large
surface area with respect to its volume can be used.
Figure 2 shows an embodiment that provides a large surface area to volume
ratio. In this
example, the humidifter 10 has a capsule 12 is formed as a multi-pointed,
three-dimensional
star shape, with a plurality of spokes or fingers 18 extending from a central
core; these
together form a single closed volume. This volume is filled with water 14
(liquid or
absorbed in a material as discussed above). The star provides a very large
surface area
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through which water vapour 16 is released, so that a large amount of water
vapour is
delivered relatively quickly.
Figure 3 shows a further embodiment designed to increase the surface area. In
this
example, the humidifier 10 has a capsule 12 formed from ePTFE with a
corrugated surface
20, which again provides a large surface area for the release of water vapour
16.
A humidifier according to the present invention can be included inside a
package of
tobacco product as the package is filled and before it is sealed for shipping
and/or storage
/0 before purchase and use by a customer. The presence of the humidifying
capsule inside the
package keeps the tobacco moist until it is used.
Alternatively, the humidifier may be supplied separately for use as and when a
smoker finds
that their tobacco product needs additional moisture, whereupon the humidifter
can be
inserted into the container holding the product. However, for this it is
necessary to prevent
the water inside the capsule from evaporating before it is desired to use the
humidifier. It is
therefore proposed that the humidifier may be supplied packaged inside an
outer layer that
is substantially impermeable to the passage of water vapour and liquid water
and which is
removed from the humidifier before use. In this form, the humidifier can be
supplied as a
separate item, or may be included inside a package of tobacco product for
optional use
after the package is opened. The outer layer will retain the water
substantially inside the
capsule until such time as the outer layer is removed, whereupon the time
water vapour can
escape through the ePTFE to the environment of the humidifier.
Figure 4 shows a cross-sectional view of a humidifier according to this
embodiment. The
humidifier 10, shown in the low surface area form of Figure 1 for simplicity
(the capsule
may in reality have any shape) is sealed inside an impermeable outer layer 22.
Any suitable
configuration and material may be used for the outer layer 22, including a
sealed plastics
material packet or a tin or plastic box with a removable resealable lid. A box
or tin may be
used to supply a plurality of humidiflers in a single batch. In this example,
however, the
outer layer 22 is made from a flexible plastics material configured as a
sachet inside which
the capsule 12 containing the water 14 is sealed. The sachet 22 may be, for
example, of the
type commonly used to provide individual portions of condiments in catering
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establishments, since these are simple and economical to manufacture, easy to
open and
remove, and use known packaging technology.
Figure 5 shows a plan view of the packaged humidifier of Figure 4. The sachet
22 is sealed
across each end by sealing lines 24 made for example by plastics welding.
Portions of the
sachet material extend a short distance beyond the sealing lines 24 and
terminate in serrated
edges 26, which facilitate tearing open of the sachet for removal of the
humidifier 10 prior
to use. The outer surface of the sachet 22 may be printed with any desired
design, for
example a brand name and instructions for use of the humidifier 10.
Further in this regard, the outer surface of the humidifier capsule 12 may
also be provided
with a desired design such as a brand name or logo if the ePTFE is of the
laminated fabric
form, since a design can be woven into or printed onto the fabric with which
the ePTFE is
laminated.
For a humidifier that is enclosed inside an impermeable outer layer, the user
may be
assisted in determining when the humidifier should be employed by the
inclusion of a
humidity indicator on the exterior surface of the outer layer. If the
humidifier, inside its
outer layer, is stored inside the packaging of the tobacco product, the
indicator can then
show when it should be used. The indicator can be any type of compact humidity
measuring device or sensor that gives a visual indication of the humidity
level. A
convenient example is a cardboard or paper device comprising one or more
sensor areas of
water-sensitive material that absorb moisture from the atmosphere and change
colour
according to whether the humidity is above or below some threshold value. A
range of
sensor areas having different threshold values may be provided, to give a
visual humidity
scale from which the user can make a decision as to whether his tobacco
product is
appropriately moist; if the atmosphere becomes dry the outer layer can be
opened and the
humidifier removed for use. Alternatively, a single sensor area can be
provided to give one
threshold humidity measurement so that the humidifier can be activated if the
humidity
drops below the threshold. The threshold can be selected at a useful level for
humidity at
which tobacco is satisfactorily moist.
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Figure 6 shows a plan view of a humidifier packaged in a sachet 22 as shown in
Figure 5
which has a humidity indicator 28 on its exterior surface. The humidity
indicator 28 has a
plurality of sensor areas 30.
As mentioned above, humidifiers according to the present invention can be
supplied as
products in their own right for insertion in a package or container of tobacco
product by
the user, in which case the humidifier has a removable impermeable outer
layer.
Alternatively, humidifiers can be included inside the packaging of pre-
packaged tobacco
products. In the latter case, the humidifier may lack the impermeable outer
layer, so that it
/0 maintains the moisture level of the tobacco before the package is opened by
the user, or it
may include an outer layer so that it is available for use after the package
is opened if the
user wants to raise the moisture level. For either of these possibilities, the
humidifier can
either be included loose inside the packaging, or it can be incorporated into
the packaging,
for example by being glued to an interior surface of the packaging. Such a
humidifier is
widely applicable to many types of tobacco packaging.
Figure 7 shows a perspective view of the top part of a pack 38 for smoking
articles such as
cigarettes or cigars. The pack 38 has a hinged flip-top lid 40 which has a
humidifter 10
according to an embodiment of the present invention adhered to the inside
surface of its
upper face, where it can be easily seen and accessed by a user. It may be
positioned
elsewhere on the inner surface of the pack, however. Note that the smoking
articles which
would be supplied in the pack 38 have been omitted from the Figure in the
interests of
clarity.
Figure 8 shows a cross-sectional side view of a pouch 42 containing loose
tobacco for
rolling or pipe smoking. The pouch 12 comprises a bag-like container portion
46 for
holding the tobacco 44, and a closure portion 48 in the form of a flap that
folds over and
wraps around the container portion to keep the pouch 42 closed and the tobacco
44 moist.
A humidifier 10 is adhered to the upper part of the inside surface of the rear
wall of the
container portion 46.
Figure 9 shows a perspective view of a tin 50 for holding loose tobacco 44,
the tin 50
having a lid 52 with a humidifler on its inside surface.
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In each of the examples of Figure 7, 8, and 9, the humidifier 10 may be
provided with an
impermeable outer layer that can be removed to allow the humidifier to be
brought into
use by the smoker after the package is opened. Since the rear surface of the
humidifier is in
contact with the package, there is no need for the outer layer to completely
enclose the
humidifier. Instead, a peel-off layer of impermeable material such as foil or
plastic may be
adhered over the humidifier using non-permanent adhesive.
Also, in each of the examples of Figures 7, 8 and 9, the capsule 12 of the
humidifier 10
/0 need not be wholly fabricated from ePTFE. A rear surface of the humidifier
10 is adhered
to an inside surface of the packaging, so water vapour cannot escape through
that part of
the capsule. Hence, a non-permeable material may be used for part of the
capsule if
preferred, for example for cost reasons. Additionally, it may be advantageous
for the part
of the capsule that is in contact with the packaging not to release water
vapour, since the
water may adversely affect the packaging material, for example in the case of
a cardboard
cigarette or cigar pack.
Further in this regard, embodiments of humidifier which are not intended to be
adhered to
the inner surface of tobacco product packaging may also have a capsule that is
only
partially comprised from ePTFE. The ePTFE can be used to provide a "window"
through
which water vapour is released from an otherwise impermeable capsule, for
example. This
gives a further flexibility in designing the rate of water vapour release,
where the size of the
window in conjunction with the size and density of the pores in the ePTFE
determines the
release of the water vapour.
Figure 10 shows a cross-sectional side view of a humidifier according to an
example of this
embodiment. The humidifier 10 has a capsule that comprises an open tray
portion 54 that
is fiIled with water 14 (as liquid or absorbed in a material). The tray 54 is
sealed with a layer
of ePTFE 56 over its upper surface. The tray 54 maybe formed from plastics
material by
blow moulding or vacuum moulding, before the water is added and the ePTFE
layer 56
sealed around the perimeter of the tray 54. The structure is similar to that
of a single cell in
the blister packs used to package tablets, with the difference that the
contents are not
intended to be removed. A removable impermeable outer layer (not shown) may be
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provided over the ePTFE layer to seal in the water vapour prior to use.
Alternatively, a
humidifler according to this embodiment may be sealed inside a fully enclosing
outer layer,
such as the sachet of Figures 4 and 5.
Humidifiers of the present invention may be fabricated according to any
convenient
technique.
Figure 11 illustrates one example technique in which the capsule 12, in this
example fully
fabricated from ePTFE, is fully constructed so as to form a sealed pouch.
Then, liquid
/0 water 14 is injected into the capsule 12 using a needle that penetrates
through the capsule
12. A simple syringe 58 is shown for illustrative purposes. For large scale
manufacturing, a
larger injection unit will be more appropriate. For embodiments which have a
moisture
releasing element in the form of a water-absorbing medium into which water is
absorbed,
the water-absorbing medium is placed inside the capsule 12 before it is fully
sealed (or the
capsule is constructed around the material if more convenient). The water 14
is then
injected into the material inside the capsule 12.
Figures 12A-12E illustrate steps in a further example technique intended to
address any
difficulties arising from manufacturing with liquid water. In this example,
the water 14 is
provided in frozen form, as shown in Figure 12A. The frozen water may be
simply an ice-
cube, if a reservoir of plain liquid water is required. Alternatively, the
frozen water may
include one or more of the additional substances described above, such as
flavorants. Also,
for some of the water-absorbing materials that can be used as a moisture
releasing element,
it may be possible to provide these, with the water already absorbed inside,
in frozen form.
A partially assembled, still open, capsule 12 is provided. This may be merely
the separate
pieces of the ePTFE which will form the capsule, or these pieces may be
partially formed
into a capsule 12 which is not yet sealed shut. Figure 12B shows a partially
formed open
capsule 12 of this type, the capsule having the form of a bag into which the
frozen water 14
can be placed.
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As shown in Figure 12C, the frozen water 14 is then placed inside the
partially assembled
capsule 12, either by inserting it into an open bag-like capsule or by placing
the separate
pieces of ePTFE around the frozen water.
Next, the capsule is sealed shut around the frozen water. Any as yet unmade
joins between
the pieces of ePTFE are bonded, stitched or otherwise completed. Figure 12D
shows the
result, in which the frozen water 14 is fully encapsulated in the capsule 12.
Finally, the frozen water 14 melts to provide the required moisture-releasing
element 14
>0 (liquid water or water absorbed in a medium) inside the capsule 14, giving
the finished
humidifier 10.
The invention is not limited to the fabrication techniques of Figures 11 and
12. Any
suitable technique may be employed.
It is intended that humidifiers according to the present invention will
generally be
disposable. However, once all the encapsulated water has evaporated, it would
be possible
for the humidifier to be re-used if the user injected more water into the
capsule.
The humidifters described herein are suitable for use with any tobacco product
(and also
with any other packaged product that requires moisture levels to be maintained
or
rejuvenated). The size of any humidifier will therefore be selected according
to the tobacco
packaging in which it is intended to be used. Based on the typical size of a
tobacco pouch
or tin or a cigarette or cigar pack, the humidifters will typically have
dimensions of between
10 and 50 millimetres. Other sizes are not precluded, however.
Humidifiers according to the invention may include further features in various
combinations. For example, the encapsulated moisture source may comprise a gel
configured for the controlled release of moisture. Humidifiers incorporating
such gels are
described in our co-pending application GB 0710784.0 "Controlled moisture
release
humidifier for use with tobacco products", filed in the United Kingdom on 5th
June 2007.
Also, the humidifiers may include an additional sealed compartment containing
a
supercoolable salt hydrate solution that can be activated to crystallise and
release heat to
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the moisture-releasing element, thereby increasing the rate of moisture
release by
evaporation. Humidifiers comprising such "heat releasing gels" are described
in our co-
pending application GB 0710776.6 "Heatable humidifying device for use with
tobacco
products", filed in the United Kingdom on 5th June 2007.
