Note: Descriptions are shown in the official language in which they were submitted.
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Products Including Capsules, Uses and Preparation Thereof
Field
The present invention relates to capsules for incorporation into a tobacco
product and
methods of making the same.
Background
The sensory attributes of a tobacco product can be altered by applying
additives to the
tobacco product. For example, some tobacco products contain capsules, and the
/o contents of the capsules are released into the tobacco product upon
rupture of those
capsules. The capsules incorporated in the tobacco products can be
manufactured using
various materials and by various methods.
Summary
/5 According to a first aspect, there is provided a tobacco product or part
thereof
comprising a core-shell capsule, wherein the capsule shell comprises cellulose
acetate
and/or a derivative thereof and the core-shell capsule is formed by a method
comprising diffusion.
20 According to a second aspect, there is provided a use of a core-shell
capsule in a tobacco
product or part thereof, wherein the capsule shell comprises cellulose acetate
and/or a
derivative thereof and the core-shell capsule is formed by a method comprising
diffusion.
25 According to a third aspect, there is provided a method for the
manufacture of a
tobacco product or part thereof comprising a core-shell capsule, the process
comprising:
preparing a carrier structure from a carrier material;
encapsulating said carrier structure with a film forming material comprising
30 cellulose acetate and/or a derivative thereof so as to form a shell
completely
surrounding the carrier structure;
exposing said encapsulated carrier structure to a medium in which said carrier
material is soluble or dispersible, so that the carrier material is at least
partially
removed from within the shell by diffusion;
35 removing the resultant core-shell capsule from said medium; and
incorporating the core-shell capsule into a tobacco product or part thereof.
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In some embodiments of the method, the resultant core-shell capsule comprises
an
additive. In some embodiments, said additive is present in the medium and at
least
some of the additive diffuses into the capsule through the shell as the
carrier material is
at least partially removed. Additionally or alternatively, the additive is
present in the
carrier material and at least some of the additive remains within the capsule
as the
carrier material is at least partially removed.
In some embodiments of the first, second and/or third aspects, the tobacco
product is a
io smoking article or a smokeless oral tobacco product. In some
embodiments, the
tobacco product part is a filter or a filter element, or is a rod or portion
of tobacco.
Brief Description of the Figures
Embodiments of the present invention will now be described, by way of example
only,
with reference to the accompanying drawings, in which:
Figure 1 is a schematic illustration of a cross-section of a smoking article
containing a
core-shell capsule according to some embodiments of the present invention;
Figure 2 is a schematic illustration of a cross-section of a smoking article
containing a
plurality of core-shell capsules according to some embodiments of the present
invention;
Figure 3 is a schematic illustration of a cross-section of a smokeless oral
tobacco
product containing a core-shell capsule according to some embodiments of the
present
invention; and
Figure 4 is a schematic illustration of a cross-section of a core-shell
capsule according
to some embodiments of the present invention.
Detailed Description
There is provided a tobacco product or part thereof comprising a core-shell
capsule, the
capsule shell comprising cellulose acetate and/or a derivative thereof.
As used herein, the term "core-shell capsule" includes capsules that comprise
a core
and a shell.
As used herein, the term "tobacco product" includes smokeless oral tobacco
products
and smokeable tobacco products, such as smoking articles.
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As used herein, the term "smoking article" includes smokeable products such as
cigarettes, cigars and cigarillos whether based on tobacco, tobacco
derivatives,
expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-
not-burn
products (i.e. products in which flavour is generated from a smoking material
by the
application of heat without causing combustion of the material) and other
articles
capable of generating tobacco-derived aerosols. Typically, smoking articles
are
provided with filters for removing constituents from the gaseous flow.
As used herein, the term "smokeless oral tobacco product" includes any
smokeless
/o tobacco product designed to be placed in the oral cavity of a user for a
limited period of
time, during which there is contact between the user's saliva and the product.
The core-shell capsule is formed by a method which involves diffusion. In some
embodiments, the core-shell capsule is formed by a method based on diffusional
/5 exchange.
As used herein, the term "diffusional exchange" is used to refer to the
exchange of one
or more substances across a barrier or membrane by diffusion.
20 In some embodiments, the core-shell capsule is not produced by
electrospraying or
electroprocessing.
Figure 1 shows a cross-section of a smoking article 10 in which a core-shell
capsule 1 is
incorporated into the filter 2 of the smoking article 10, in accordance with
an
25 embodiment of the invention. The smoking article lo comprises a rod of
smokeable
material 6 and a filter 2. The rod of smokeable material 6 and filter 2 shown
in Figure 1
are attached to each other by tipping paper 3, although other means for
attaching the
rods of smokeable material to a filter that are known in the art may be
employed in the
alternative. In the illustrated embodiment, the filter 2 is wrapped in a
length of tipping
30 paper 3 which is longer than the filter 2 and connects the rod of
smokeable material 6
to the filter 2 in a manner well known in the art. The filter 2 of the smoking
article lo
may be wrapped in a plugwrap 4 in addition to the tipping paper 3. The rod of
smokeable material 6 may be formed from cut rag tobacco, reconstituted and/or
pelletised tobacco and is circumscribed by a wrapper 5.
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The core-shell capsule 1 may be positioned largely centrally along the length
of the filter
2 of the smoking article 10. Alternatively, the core-shell capsule may be
positioned
towards or at one end of the filter 2, such as towards the end of the filter 2
adjacent to
the rod of smokeable material 6 of the smoking article 10, or towards the end
of the
filter 2 which forms the mouth end of the smoking article 10.
The core-shell capsule 1 may be positioned largely along the longitudinal axis
of the
filter 2 of the smoking article 10. Alternatively, the core-shell capsule may
be positioned
towards the periphery of the filter 2 of the smoking article lo (not shown).
The filter 2 can comprise two or more filter elements. The filter or filter
elements may
be any conventional filter or filter element known to a person skilled in the
art. For
example, the filter or element may comprise any filter material or combination
of filter
materials. A smoking article may comprise multiple filter elements and at
least one
/5 cavity, the cavity being positioned between two filter elements or at
one end of the
filter.
In some embodiments, the tobacco product comprises a single core-shell capsule
1. In
alternative embodiments, the tobacco product comprises a plurality of core-
shell
capsules 1.
Figure 2 shows a cross-section of a smoking article 20 containing a plurality
of core-
shell capsules 11 arranged in a spaced configuration along the longitudinal
axis of the
smoking article 20, in accordance with an embodiment of the invention. In some
embodiments, the capsules 11 are positioned peripherally or in a more random
configuration.
In Figure 2, the capsules 11 are positioned wholly within the rod of smokeable
material
16. In other embodiments, some or all of the capsules 11 may be positioned
within one
or more other component(s) of the smoking article 20, such as the filter 12.
In some embodiments (not shown), one or more capsule(s) 11 are positioned
between
one or more of the component(s) of a smoking article 20. For example, one or
more
capsules 11 may be positioned between the filter 12 and the rod of smokeable
material
16 of the smoking article 20.
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In some embodiments (not shown), the capsules 11 may be positioned so that
they are
partially within the tobacco product or part thereof.
Figure 3 shows a cross-section of a smokeless oral tobacco product 30
containing a
core-shell capsule 21 arranged within the tobacco-containing material 26 of
the product
30, in accordance with an embodiment of the invention. In some embodiments
(not
illustrated) the product has a plurality of capsules distributed within the
tobacco-
containing material 26. The capsules may all be the same or they may be
different, for
example containing different additives and/or having different configurations,
for
/o example some having an outer coating and some not.
The capsules incorporated into different products or into different parts of
products,
such as those described with reference to Figures 1 to 3 above, may be
different. For
example, the physical characteristics of the capsules may be different and may
be
/5 selected to be optimised for the particular use. As an example, capsules
incorporated
into the filter of a smoking article may differ to those that are incorporated
into the rod
of smokeable material of a smoking article; they might have a smaller
diameter.
Additionally or alternatively, capsules of a smaller diameter may be used
where a
plurality of capsules are to be incorporated into a single product.
Figure 4 shows a cross-section of a core-shell capsule 31 according to some
embodiments. The capsule illustrated in Figure 4 and described below may, in
some
embodiments, be used in any of the embodiments illustrated in Figures 1 to 3
and
described herein. The core-shell capsule 31 comprises a shell 32 and an
internal core
33. In this embodiment, the shell is coated with an outer coating 34.
The shell 32 of the core-shell capsule 31 comprises cellulose acetate and/or a
derivative
thereof. Suitable cellulose acetate derivatives will be known to the person
skilled in the
art. In some embodiments, the shell 32 comprises cellulose acetate phthalate,
referred
to herein as cellulose phthalate. In some embodiments, the shell 32 comprises
cellulose
triacetate. In some embodiments, the shell material consists essentially of
cellulose
acetate and/or derivatives thereof. In some embodiments, the shell material
comprises
cellulose derivatives. In some embodiments, the shell material does not
comprise
gelatin.
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In some embodiments, the shell 32 comprises a continuous layer or film of
shell
material. In other words, the shell material may form a continuous coating
around the
internal core 33 of the capsule without the need to plug any holes in the
shell or to seal
one or more edges or sections of the shell material together.
In some embodiments, the shell 32 of the core-shell capsule 31 is coloured. In
some
embodiments, the colouring is food grade colouring. In some embodiments, the
shell
32 is a different colour from the core 33 of the core-shell capsule 31. Such
an
arrangement may be advantageous for determining whether the core 33 is
completely
io coated by the shell 32.
In some embodiments, the internal core 33 of the core-shell capsule 31
comprises an
additive. The additive may be any substance that modifies and/or enhances the
characteristics of the tobacco product, such as the sensory attributes of a
tobacco
product. For example, when the core-shell capsule 31 is incorporated into a
smoking
article, the additive may be anything which may be added to smoke and/or which
may
modify the composition of smoke.
The additive may be in solid, liquid and/or gaseous phase. In some
embodiments, the
additive is in liquid phase. In some embodiments in which the core-shell
capsule 31 is
placed in a smoking article, the additive changes phase during use of the
smoking
article. Such an arrangement may advantageously release more additive during
use of
the smoking article. In some embodiments, the additive in the core-shell
capsule 31
changes from solid phase to liquid phase during use of the smoking article.
The additive may be a flavour or flavourant (where permitted by local
regulations), a
deodoriser, a diluent, an adsorbent, or any other substance that is capable of
modifying
the tobacco product. The additive may comprise, consist essentially of and/or
consist of
water. The additive may comprise at least 50% water, at least 75% water, at
least 80%
water, at least 85% water, at least 90% water, at least 95% water and/or l00%
water.
As used herein, the terms "flavour" and "flavourant" refer to materials which,
where
local regulations permit, may be used to create a desired taste or aroma in a
product for
adult consumers. They may include extracts (e.g., licorice, hydrangea,
Japanese white
bark magnolia leaf, chamomile, fenugreek, clove, menthol, Japanese mint,
aniseed,
cinnamon, herb, wintergreen, cherry, berry, peach, apple, Drambuie, bourbon,
scotch,
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whiskey, spearmint, peppermint, lavender, cardamon, celery, cascarilla,
nutmeg,
sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil,
orange oil,
cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger,
anise,
coriander, coffee, or a mint oil from any species of the genus Mentha),
flavour
enhancers, bitterness receptor site blockers, sensorial receptor site
activators or
stimulators, sugars and/or sugar substitutes (e.g., sucralose, acesulfame
potassium,
aspartame, saccharine, cyclamates, lactose, sucrose, glucose, fructose,
sorbitol, or
mannitol), and other additives such as charcoal, chlorophyll, minerals,
botanicals, or
breath freshening agents. They may be imitation, synthetic or natural
ingredients or
/o blends thereof. They may be in any suitable form, for example, oil,
liquid, or powder.
In some embodiments, the additive comprises menthol. The additive may comprise
at
least 50% menthol, at least 75% menthol, at least 80% menthol, at least 85%
menthol,
at least 90% menthol, at least 95% menthol and/or approximately l00% menthol.
In some embodiments, the additive comprises Kreteks-style flavours, clove
extract
and/or any natural or synthesised compound that may be present in cloves or
clove
extract, such as eugenol.
In some embodiments, the additive may mixed with a solvent. Suitable solvents
will be
known to the person skilled in the art. In some embodiments in which the
additive
comprises menthol, propylene glycol may be a suitable solvent.
Alternatively or in addition, the additive in the internal core 33 of the core-
shell capsule
31 may comprise a carrier material. In some embodiments, the carrier material
is
and/or comprises polyethylene glycol (also known as PEG).
The internal core 33 of the core-shell capsule 31 may contain a single type of
additive.
Alternatively, the internal core 33 may contain a plurality of types of
additive. In some
embodiments, the internal core 33 comprises two different types of additives.
For
example, the different additive types may be different flavourants, or, one
type may be a
flavourant and another type may be an additive which is not a flavourant.
In some embodiments, the core-shell capsule 31 may be coated with an outer
coating
34. This outer coating is optional, but may be preferred in some embodiments.
In some
embodiments, the outer coating 34 may be a moisture-impermeable coating. The
moisture-impermeable layer may serve to ensure that any additive in the inner
core 33
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is retained in the core-shell capsule 31 until it is desirable for the
additive to be
released. In embodiments in which the internal core 33 of the core-shell
capsule 31
comprises an additive material that is water-soluble, or includes or is water,
the outer
coating 34 may be impermeable or substantially impermeable to water.
The core-shell capsule 31 may comprise more than one outer coating 34. In
these
embodiments, the plurality of outer coatings 34 may have the same or
substantially the
same composition of materials. Alternatively, the composition of the plurality
of the
outer coatings may be different.
Suitable materials for the outer coating 34 will be known to the person
skilled in the aft.
In some embodiments, the outer coating 34 comprises wax, such as castor wax,
bees
wax, carnauba wax, or a combination thereof.
/5 Alternatively or in addition, the outer coating 34 may comprise
cellulose acetate and/or
one or more cellulose derivatives. Suitable cellulose derivatives will be
known to the
person skilled in the aft, and may comprise hydroxypropyl methylcellulose
(HPMC)
and/or carboxymethyl cellulose (CMC).
Alternatively or in addition, the outer coating 34 may comprise one or more
plasticiser(s). As used herein, the term 'plasticiser' includes softeners but
does not
include water.
The one or more plasticiser(s) may be used to effect and/or assist in the
impermeabilisation of the outer coating 34 of the core-shell capsule 31. The
one or
more plasticiser(s) may achieve this by limiting or reducing the leakage of
the internal
core 33 to outside of the core-shell capsule 31.
Alternatively or in addition, the shell 32 of the core-shell capsule 31 may
comprise one
or more plasticiser(s). The one or more plasticiser(s) may be used to effect
and/or assist
in the impermeabilisation of the shell 32 of the core-shell capsule 31. The
one or more
plasticiser(s) may achieve this by limiting or reducing the leakage of the
internal core
33, when it is in a liquid or gaseous phase, to outside of the core-shell
capsule 31.
In embodiments in which the shell 32 of the core-shell capsule 31 comprises
one or
more plasticiser(s), if the material of the shell 32 of the core-shell capsule
31 is a
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substance that could also be considered to be a plasticiser, the at least one
plasticiser is
a substance different from the material of the shell 32 of the core-shell
capsule 31.
In some embodiments, the at least one plasticiser is impermeable to water
and/or is
liposoluble. In some embodiments, the at least one plasticiser is impermeable
to fats
and/or is water-soluble.
The at least one plasticiser may be selected from a group comprising
triacetin, dibutyl
phthalate, dibutyl sebacate, diethyl phthalate, dimethyl phthalate,
acetyltributyl citrate,
acetyltriethyl citrate, diacetylated monoglycerides, dibutyl sebacate, mineral
oil, benzyl
benzoate, chlorbutanol, glycerin monostearate, lanolin alcohols and cellulose
acetate
phthalate compatible plasticisers. These compounds are particularly suitable
when it is
desirable for the shell 32 and/or the outer coating 34 of the core-shell
capsule 34 to be
liposoluble.
Alternatively or in addition, the at least one plasticiser may be selected
from a group
comprising polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA).
Alternatively or in addition, the at least one plasticiser may be selected
from a group
comprising triethyl citrate, triacetin, benzyl benzoate, dibutyl phthalate and
2,5-
dimethylpyrazin.
In some embodiments, the core-shell capsule 31 comprises 0.1 to 30 wt.%
plasticiser.
The core-shell capsule may comprise 0.5 to 20 Wt.%, 1 to 15 wt.% and/or 2 to
10 Wt.%
plasticiser. The core-shell capsule 31 may comprise 4 to 8 wt.% plasticiser.
In some embodiments, the outer coating 34 of the core-shell capsule 31
comprises more
than 15 wt.%, more than 20 wt.%, more than 25 wt.%, more than 30 wt.%, more
than
wt.%, more than 40 wt.%, or more than 45 wt.% plasticiser said percentage
referring
30 to the weight of the outer coating 34. In some embodiments, the outer
coating 34 of the
core-shell capsule 31 comprises at least 15 wt.%, at least 20 wt.%, at least
25 wt.%, at
least 30 wt.%, at least 35 wt.%, at least 40 wt.% or at least 45 wt.%
plasticiser.
In some embodiments, the shell 32 of the core-shell capsule 31 comprises less
than 40
35 wt.% plasticiser, said percentage referring to the weight of the shell
32. The shell 32
may comprise less than 30 wt.%, less than 20 wt.%, less than 10 wt.%, less
than 5 wt.%
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or less than 3 wt.% plasticiser. In some embodiments, the shell 32 of the core-
shell
capsule 31 is free or substantially free from plasticiser.
In some embodiments, the shell 32 of the core-shell capsule 31 comprises at
least 1
wt.%, at least 2 wt.% at least 5 wt.% or at least 10 wt.% plasticiser, said
percentage
referring to the weight of the shell 32.
In some embodiments, the outer coating 34 of the core-shell capsule 31
comprises one
or more plasticiser(s) and the shell 32 of the core-shell capsule 31 is free
or
/o substantially free of plasticiser. In some embodiments, the outer
coating 34 comprises a
greater amount of plasticiser in percent by weight than the shell 32 of the
core-shell
capsule 31.
In some embodiments, the shell 32 of the core-shell capsule 31 is
substantially free of
/5 plasticiser and the outer coating 34 comprises at least 1 wt.%, at least
3 wt.%, at least 5
wt.% , at least 8 wt.% or at least 10 wt.% plasticiser, said percentage
referring to the
weight of the outer coating 34.
In some embodiments in which the additive in the internal core 33 of the core-
shell
20 capsule 31 comprises water, the core-shell capsule 31 is impermeable to
water, so that,
when stored for 1 month at 25 C at a relative humidity (rH) of 75%, at least
some of the
water is retained in the internal core 33 of the core-shell capsule 31. Under
these
conditions, at least 40 wt.%, at least 50 wt.%, at least 60 wt.% or at least
70 wt.% of the
water may be retained in the internal core 33 of the core-shell capsule 31,
compared to
25 the start of said i-month period and/or to the initial water content.
In some embodiments in which the additive in the internal core 33 of the core-
shell
capsule 31 comprises water, the core-shell capsule 31 is impermeable to water,
so that,
when stored for 2 months at 25 C at a relative humidity (rH) of 75%, at least
some of
30 the water is retained in the internal core 33 of the core-shell capsule
31. Under these
conditions, at least 40 wt.%, at least 50 wt.%, at least 60 wt.% or at least
70 wt.% of the
water may be retained in the internal core 33 of the core-shell capsule 31,
compared to
the start of said 2-month period and/or to the initial water content.
35 In some embodiments in which the additive in the internal core 33 of the
core-shell
capsule 31 comprises water, the core-shell capsule 31 is impermeable to water,
so that,
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when stored for 3 months at 25 C at a relative humidity (rH) of 75%, at least
some of
the water is retained in the internal core 33 of the core-shell capsule 31.
Under these
conditions, at least 40 wt.%, at least 50 wt.%, at least 60 wt.% or at least
70 wt.% of the
water may be retained in the internal core 33 of the core-shell capsule 31,
compared to
the start of said 3-month period and/or to the initial water content.
In some embodiments in which the additive in the internal core 33 of the core-
shell
capsule 31 comprises water, the core-shell capsule 31 is impermeable to water,
so that,
when stored for 4 months at 25 C at a relative humidity (rH) of 75%, at least
some of
io the water is retained in the internal core 33 of the core-shell capsule
31. Under these
conditions, at least 40 wt.%, at least 50 wt.%, at least 60 wt.% or at least
70 wt.% of the
water may be retained in the internal core 33 of the core-shell capsule 31,
compared to
the start of said 4-month period and/or to the initial water content.
In some embodiments in which the additive in the internal core 33 of the core-
shell
capsule 31 comprises water, the core-shell capsule 31 is impermeable to water,
so that,
when stored for 5 months at 25 C at a relative humidity (rH) of 75%, at least
some of
the water is retained in the internal core 33 of the core-shell capsule 31.
Under these
conditions, at least 40 wt.%, at least 50 wt.%, at least 60 wt.% or at least
70 wt.% of the
water may be retained in the internal core 33 of the core-shell capsule 31,
compared to
the start of said 5-month period and/or to the initial water content.
In some embodiments in which the additive in the internal core 33 of the core-
shell
capsule 31 comprises water, the core-shell capsule 31 is impermeable to water,
so that,
when stored for 6 months at 25 C at a relative humidity (rH) of 75%, at least
some of
the water is retained in the internal core 33 of the core-shell capsule 31.
Under these
conditions, at least 40 wt.%, at least 50 wt.%, at least 60 wt.% or at least
70 wt.% of the
water may be retained in the internal core 33 of the core-shell capsule 31,
compared to
the start of said 6-month period and/or to the initial water content.
The core-shell capsule 31 may be a suitable size to be incorporated into a
tobacco
product.
In some embodiments, optionally including the embodiments described above and
illustrated in Figures 1 to 3, the core-shell capsule has a diameter within
the range 1.5 to
10 mm, and optionally within the range 2 to 8 mm. In some embodiments, the
core-
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shell capsule has a diameter in the range 3 to 5 mm, optionally 3.4 to 4.8 mm
and
further optionally 3.5 to 4.5 mm. In some embodiments, the core-shell capsule
has a
diameter in the range of 2.5 to 4 mm. In some embodiments, the core-shell
capsule has
a diameter of about 3.5 mm. In some embodiments, the core-shell capsule has a
diameter of 1 mm, at least 1.5 mm, at least 2 mm, at least 2.5 mm, at least 3
mm, at
least 3.1 mm, at least 3.2 mm, at least 3.3 mm, at least 3.4 mm, at least 3.5
mm, at least
3.6 mm, at least 3.7 mm, at least 3.8 mm, at least 3.9 mm, at least 4 mm, at
least 4.5
mm, at least 5 mm, at least 6 mm, at least 7 mm, at least 8 mm, at least 9 mm,
or at
least lo mm. In some embodiments, the core-shell capsule has a diameter of at
least 2
/0 mm. In some embodiments, the core-shell capsule has a diameter of
greater than 1 mm,
greater than 2 mm, greater than 3 mm or greater than 4 mm.
In some embodiments, the core-shell capsule is not a microcapsule or a
nanocapsule.
As used herein, the terms "microcapsule" and "nanocapsule" refer to capsules
with a
/5 diameter of less than 1 mm and less than 1 lam, respectively.
The average capsule size may be determined by laser diffraction analysis, in
particular
as specified in the international standard ISO 13320-1. For example, a Malvern
Mastersizer 3000 may be used. This methodology is useful for determining
average
20 capsule sizes in the range of 0.2 lam to 3.5 mm. For larger diameters
(such as diameters
greater than 3.5 mm), the average diameter can be determined by manually
measuring,
if applicable using a microscope, a statistically representative sample of the
capsules.
The average is the arithmetic mean for the purpose of this specification.
25 In some embodiments the core-shell capsule is spherical or substantially
spherical.
Alternatively, the core-shell capsule may be elongate, optionally with a
longitudinal axis
extending parallel to a longitudinal axis of the tobacco product.
Generally, the contents of the core-shell capsule are to be released prior to
and/or
30 during use, and in some circumstances even after use of the tobacco
product or part
thereof into which the capsule has been incorporated. The contents of the core-
shell
capsule may be released by any suitable means. In some embodiments, the
contents of
the core-shell capsule are released by rupturing the capsule, so as to release
the additive
at a predetermined moment. In other words, the core-shell capsule may be
rupturable.
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In some embodiments in which the core-shell capsule 31 is in a tobacco
product, the
user can break the capsule by breaking the shell 32 and/or the outer coating
34 of the
capsule 31 by applying pressure to the part of the tobacco product which
surrounds the
core-shell capsule 31. For example, in embodiments in which the core-shell
capsule 31
is positioned within a filter of a smoking article, the shell 32 and/or the
outer coating
34 of the capsule 31 may be ruptured by applying pressure to the external
surface of the
filter.
The core-shell capsules of the present invention are produced by a process
that is based
io on diffusion through the shell of core-shell capsules. Surprisingly, by
using a multiple
step process, the inventors have overcome the limitations of prior art
methods, which
are virtually all limited to a small range of capsule sizes.
In some embodiments, the method comprises the steps of producing a shell of
core-
/5 shell capsules, exposing said shell to a medium comprising an additive
and allowing the
diffusion and/or osmosis of the additive through said shell.
In some embodiments, the method comprises the steps of: producing a precursor
core-
shell capsule comprising a carrier structure or core encapsulated by a film-
forming
20 material forming a shell; and exposing said precursor core-shell capsule
to conditions
that result in the diffusion and/or osmosis of at least part of the material
of the carrier
structure from the core through the shell to the outside of the shell.
In some embodiments, the method comprises the steps of: producing a precursor
core-
25 shell capsule comprising a carrier structure or core and an additive
encapsulated by a
film-forming material forming a shell; exposing said precursor core-shell
capsule to
conditions that result in the diffusion and/or osmosis of at least part of the
material of
the carrier structure from the core through the shell to the outside of the
shell, while at
least some of the additive remains in the core of said capsule.
In some embodiments, the method of preparing a core-shell capsule with a core
comprising an additive comprises:
preparing a solid carrier structure from a carrier material that is
dissolvable in a
solubilising medium;
encapsulating said solid carrier structure so as to obtain an encapsulated
carrier
structure surrounded by a shell (a precursor core-shell capsule);
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exposing said encapsulated carrier structure to said medium for a duration
sufficient to at least partially replace at least some of the material of the
carrier
structure by said medium, thereby obtaining a core-shell capsule with a core
comprising said medium and a shell; and
removing the core-shell capsule from the medium.
In some embodiments, an additive is mixed with the carrier material before
and/or
during formation of the carrier structure. Alternatively or in addition, in
some
embodiments, an additive is contained in the solubilising medium.
In some embodiments, the method of preparing core-shell capsules by
countercurrent
flow diffusion comprises the steps of:
- preparing substantially spherical, self-sustained carrier beads from a
carrier
material, said carrier beads having a diameter in the range of 1 lam to 1 cm;
- encapsulating said self-sustained carrier beads with an appropriate film-
forming material to form a semi-permeable shell in order to obtain precursor
core-shell
capsules;
- exposing said precursor core-shell capsules to a solubilising medium
containing an additive, wherein said carrier material is soluble and/or
dispersible in
said medium, so as to favour diffusion of the dissolved and/or dispersed
carrier
material out of said precursor core-shell capsules and/or diffusion of said
additive into
the precursor core-shell capsules, thereby obtaining core-shell capsules
comprising an
additive.
In some embodiments, the core-shell capsule comprises a core comprising an
additive,
wherein at least part of said core and/or said additive has properties of or
comprises a
liquid at 65 C.
In some embodiments, the core-shell capsule comprises a core comprising an
additive,
wherein at least part of said core and/or said an additive is a liquid at 65
C.
In some embodiments, the core-shell capsule comprises a core, at least part of
which is
liquid, comprises a liquid or has properties of a liquid at 45 C, 35 C and/or
25 C, and a
shell, and comprising an additive, said shell comprising cellulose acetate
and/or a
derivative thereof.
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In some embodiments, the methods of the invention may comprise a step of
preparing
carrier structures, carrier cores or carrier beads from a carrier material. As
used herein,
the terms "carrier structure", "carrier bead", "carrier core" and "primary
core",
"primary beads", "primary compound", "precursor beads" and "precursor cores"
are
interchangeable and may be used for describing the same principle. The
expression
"core" expresses the fact that said carrier beads and/or cores will form the
core of
intermediate or precursor core-shell capsules. The expression "primary"
expresses that
said carrying structure is transient and will generally be replaced by the
additive or a
medium as specified elsewhere in this specification. In some embodiments, said
carrier
io beads are self-sustained. The feature of being self-sustained refers to
the fact that said
beads are sufficiently compact so as to function as a framework, allowing for
the
formation of a shell around them in a further step. Said carrier beads may
thus actually
be liquid, for example in the form of liquid beads that are suspended in a
medium, so
that said shell can be formed around said carrier cores. According to one
embodiment,
however, said beads are in a solid state, for example in the form of a crystal
or a non-
crystalline solid state, for example in a glassy state. Said feature of being
self-sustained,
for example solid, refers to the status when being subjected to the step of
shell-
formation as being described elsewhere in this specification.
One of the innovative aspects of the method of the present invention is the
making of a
primary, self-contained structure (core, beads), which serves as a scaffold to
create a
membrane around the primary core, as will be described further below.
In some embodiments, in a still further, subsequent step said beads may be
exposed to
conditions in which the beads are substantially disintegrated, for example
solubilised
and/or suspended.
In some embodiments, said carrier beads are substantially spherical.
The carrier beads may be prepared from any suitable material. Suitable
characteristics
in terms of melting point, solubility and diffusion characteristics of the
material that is
used for preparing the carrier beads are discussed elsewhere in this
specification.
According to an embodiment, said carrier material of said carrier beads is
selected from
PEG, polyvinyl alcohol (PVA), including fully, intermediate or partially
hydrolysed
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PVA, water soluble saccharides, in particular water soluble mono-, di-, oligo-
, and
polysaccharides, lipids, fats, and waxes, for example.
In some embodiments, said carrier material has a melting point that is greater
than
5 C, greater than 10 C, greater than 15 C, greater than 20 C, greater than 25
C, greater
than 30 C, greater than 35 C, greater than 40 C, greater than 45 C, greater
than 50 C
and/or greater than 60 C.
While there exist many ways for producing carrier beads that may be used in
the
io methods of this invention, the solidification of droplets of liquefied
carrier material is
cited as an example for the purpose of illustration. Accordingly, in some
embodiments,
said carrier beads are obtained by providing liquid carrier material (for
example,
liquefied carrier material) and adding droplets of liquid carrier material
into a
solidification medium, thereby obtaining said carrier beads by solidification
of said
droplets. For example, said droplets may be obtained by pumping said liquid
carrier
material through a nozzle into said solidification medium and/or by dropping
them
into the solidification medium. In some embodiments, said solidification
medium is a
liquid. In some embodiments, said solidification medium has a temperature that
is
below the melting point of said carrier material when said droplets of liquid
carrier
material are added.
In some embodiments, said carrier material has a melting point that is higher
than the
melting point of said (liquid) solidification medium. Therefore, when being
contacted
with the liquid solidification medium at a temperature that is below the
melting point
of said carrier material, said liquefied carrier material solidifies and forms
said self-
sustained carrier beads.
In some embodiments, an additive is added to said carrier material in said
carrier
beads. Said additive may be admixed with said carrier material before and/or
when
forming said carrier beads. According to an embodiment, said additive is added
to
liquid carrier material. According to this embodiment, the carrier beads
comprise a
mixture of carrier material and an additive. In this embodiment, said carrier
bead may
comprise, for example, 50 to 99 wt.%, 60 to 98 wt.%, 70 to 97 wt.% or 80-96
wt.% of
carrier material and 1 to 50 wt.%, 2 to 40 wt.%, 3 to 30 wt.% or 4 to 20 wt.%
of additive.
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According to another embodiment, said carrier beads are substantially free of
said
additive, and said additive is added at a later moment, as disclosed elsewhere
in this
specification.
According to an embodiment, said carrier beads, comprising or not said
additive, may
be washed with appropriate solvents, such as acetone, and/or with a blend of
solvents,
for example. This washing step is conducted, for example, before the
subsequent
encapsulation step.
/o In some embodiments, the methods of the invention may comprise any one
or a
combination of two or more of the steps selected from: producing a shell of
core-shell
capsules; encapsulating said carrier beads with an appropriate film-forming
and/or
polymeric material so as to obtain carrier core-shell capsules; encapsulating
said solid
carrier core so as to obtain carrier core-shell capsules; and encapsulating
said self-
/5 sustained carrier beads with an appropriate film-forming medium to form
a semi-
permeable shell in order to obtain precursor core-shell capsules.
In some embodiments, said carrier beads are encapsulated with an appropriate
material that is capable of forming a shell. In this manner, the term "carrier
core-shell
20 capsules", also interchangeably referred to as "precursor core-shell
capsules" may be
obtained. The core of said carrier or precursor core-shell capsules thus may
comprise,
consist essentially of and/or consist of the carrier material, which are
optionally
admixed with an additive in the embodiments in which the additive is added to
the
carrier beads.
Said film-forming and/or polymeric material for forming said shell may be
selected,
according to an embodiment, from materials comprising one or more selected
from
polysaccharides, polysaccharide-based materials, protein-based materials,
polyvinyl
alcohol, polyvinyl acetate, polylactic-co-glycolic acid, polylactic acid, and
combinations
comprising two or more of the aforementioned.
Examples of proteins and protein-based materials include milk proteins, such
as whey
protein and/or casein protein, cereal proteins, such as wheat protein and zein
protein
from corn, and gelatin.
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Examples of polysaccharides and polysaccharide-based materials include
cellulose
acetate, cellulose triacetate, cellulose phthalate, hydroxypropylcellulose,
ethyl cellulose,
cellulose derivatives in general, including cellulose derivatives other than
those
specified herein, chitosan, chitin, Arabic gum, alginate, pectin, pullulan,
maltodextrin,
cyclodextrin (e.g. cyclodextrin a, 13 and/or y), starch, modified starch, and
combinations comprising two or more of the aforementioned.
According to an embodiment, said film-forming and/or polymeric material is or
comprises cellulose and/or a derivative of cellulose, such as cellulose
acetate, or a
io derivative of cellulose acetate, such cellulose acetate phthalate and/or
cellulose
triacetate, for example. Cellulose and cellulose acetate derivatives may be
advantageous
in certain situations as they generally have a weak solubility in many common
solvents
such as pure water. They are, however, soluble in di- or triacetin and acetic
acid
solutions.
As will become apparent further below, the material for preparing the shell
may be
carefully selected with respect to the membrane characteristics of the shell
obtained
with the material. As described below, the shell material has to allow
diffusion from the
core into the solubilising medium and/or, once the shell is at least
partially, but may be
substantially "emptied" from its primary core, the core medium may be replaced
totally
or partially by the flow of the solubilising medium and/or additive into the
membrane.
Alternatively or in addition to the selection of the material from which it is
prepared
and the encapsulating technique used to optimise diffusion characteristics
and/or the
permeability of the shell, the thickness of the shell may be adjusted in order
to optimise
diffusion characteristics and/or the permeability of the shell.
Having the above in mind, said shell may be prepared in any suitable manner.
According to an embodiment, said step of encapsulating said carrier beads
comprises
the step of applying said film-forming and/or polymeric material onto the
solid carrier
beads. According to some embodiments, the step of encapsulating said carrier
beads
with an appropriate film-forming and/or polymeric material comprises the step
of
coating said carrier core. The coating may be performed by any suitable
apparatus. For
example, the coating may be performed by using any apparatus selected from the
group
consisting of a fluidized bed, a drum coater and a Lodige coater. If a coating
technique
is used for preparing said shell and/or encapsulating said core beads, said
coating may
be a first coating, and any one of the methods of the invention may comprise a
step of
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applying a second coating, for example in order to change (and in particular
reduce) the
permeability or diffusion characteristics of the shell, as is specified
elsewhere in this
specification.
Diffusion characteristics and/or the permeability of the shell are closely
related to the
characteristics of pore size, pore morphology and pore distribution of the
membranes
or shells. As mentioned above, also membrane or shell thickness may play role
in the
flow into and/or out of the capsules. These parameters should be kept in mind
and/or
should be determined or tested, in order to provide a shell that can be used
for the
/o purpose of the present invention.
The membrane or shell thickness may be adjusted so as to achieve the
permeability
and/or diffusion characteristics as desired with respect to the invention, in
particular as
required for the step of exposure to the solubilising medium, where the
carrier core
/5 should move to the outside of the capsule. The permeability generally
depends on the
thickness of the shell, and more specifically decreases with increasing
thickness. The
skilled person may adjust the thickness of the shell so as to optimise
diffusion
characteristics, optionally also with regard to the material (additive) to be
encapsulated.
In accordance with the invention, the weight ratio between said carrier core
and said
shell of said carrier core-shell capsules is in the range of 1-40 wt.% shell
and 60-99
wt.% core material, or 2-30 wt.% shell and 70-98 wt.% core material, or 3-25
wt.% shell
and 75-97 wt.% core material, or 5-20 wt.% shell and 80-95 wt.% core material,
or 8-15
wt,% shell and 85-92 wt.% core material, for example about 10 wt.% shell
material.
These weight ratios may also apply to the final core-shell capsules comprising
an
additive as discussed further below, possibly after a second coating step. In
this case,
the weight of the carrier core is simply replaced by the mass of the core
comprising the
additive.
In some embodiments, the thickness of the shell of the carrier core-shell
capsule may
be between 30 and 500 lam, or between 50 and 200 lam.
According to an embodiment, the shell of the carrier core-shell capsules
and/or
precursor core-shell capsules comprises pores, optionally after further
processing of the
capsules obtained after encapsulating said carrier beads.
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According to an embodiment, the shell of the carrier core-shell capsules
and/or
precursor core-shell capsules is semi-permeable, optionally after further
processing of
the capsules obtained after encapsulating said carrier beads.
According to an embodiment, the shell of the carrier core-shell capsules
and/or
precursor core-shell capsules has or is further processed to have membrane
characteristics allowing for diffusion and/or osmosis of said solubilising
medium
and/or of a liquefied and/or dissolved carrier material through said shell.
In embodiments in which a particular processing step is required in order to
render the
shell permeable and/or porous as specified above, such a step may comprise a
physical
and/or a chemical treatment that brings about said permeability. For example,
the
carrier core-shell capsules may be exposed to a solution that is corrosive to
the shell,
/5 resulting in pore formation or increase of permeability after a given
time of exposure,
for example. For example, a solution having a particular pH may be used to
provide the
necessary diffusion/permeability characteristics of the shell. Generally,
physical and/or
a chemical treatment that may be used include the exposure to pressure, to a
change of
temperature (increased and/or lowered temperatures), a change of pH and/or
combinations of two or more of these, for example.
As will be specified further below, the methods of invention may comprise a
further
step of chemically and/or physically treating the capsules to affect the
diffusion and/or
permeability properties of the capsules, but with the opposed goal, in
particular, in
order to decrease diffusion through the shell and/or permeability. In
embodiments in
which there are two steps of physical and/or chemical treatment to modify the
membrane permeability properties, the step for increasing
diffusion/permeability may
be a first step of chemically and/or physically treating or processing said
shell, and said
later step of decreasing said membrane diffusion/permeability properties may
be a
second, different step of chemically and/or physically treating or processing
said shell.
In some embodiments, at this stage, optionally after said further processing
step, the
membrane characteristics of the shell of said carrier core-shell capsules are
such that
said shell is permeable to at least the carrier material, optionally after
solubilising or
suspending the carrier material. In some embodiments, the membrane
characteristics
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of the shell at this stage are such that the shell is permeable to an
additive, which is to
be encapsulated or which may be present in the capsules at this stage already.
In some embodiments, the membrane of said carrier core-shell capsules has or
is
processed to have properties that optimise and/or favour the diffusion of the
additive
into the capsules and/or the diffusion of a solubilised (for example melted or
dissolved)
and/or suspended carrier material from the inside to the outside of the
capsules, in
particular under conditions as specified below.
io According to an embodiment, the methods of the invention may comprise
the step of
exposing said precursor core-shell capsules to conditions that result in the
diffusion
and/or osmosis of at least part of the carrier core through the shell to the
outside of the
shell. For example, these conditions may be provided by a medium.
/5 The invention takes into consideration that optimal pore characteristics
for diffusion
out of the capsule may be different from the characteristics favouring the
diffusion into
the capsule.
According to an embodiment, the methods of the invention may comprise the step
of
20 exposing said carrier core-shell capsules to a solubilising medium,
which may be a
liquid medium.
In some embodiments, said carrier material is soluble or dispersible in said
medium,
whether the medium is liquid or gaseous, for example.
According to an embodiment, said carrier material of said carrier beads, said
additive
and said (optionally liquid) solubilising medium are selected so that said
carrier
material and said additive are both soluble or dispersible in said medium,
optionally
following chemical and/or physical treatment of said medium. For example, the
solubilising medium may be provided at a temperature that is above the melting
point
of said carrier material. In this manner, the carrier material is exposed to
said
temperature when said carrier core-shell capsules are exposed to said medium.
In some
embodiments, said medium is liquid at said temperature.
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According to an embodiment, said additive and/or said carrier material are
soluble
and/or dispersible in liquid water, optionally following heating said water to
a
temperature of up to 100 C, up to 90 C, up to 70 C, or up to 60 C.
According to an embodiment, said solubilising medium is liquid at a
temperature of
70 C, 60 C, 50 C, 40 C, 30 C, 25 C, 20 C, 15 C, 10 C, 5 C, at 0 C, or possibly
even at -
5 C, for example.
According to an embodiment, said medium is a liquid medium selected from the
group
io consisting of an aqueous solution, an alcohol-containing solution, a
hydrophobic
solvent, oils, and mixtures comprising one or more of the aforementioned.
An exemplary way of exposing said carrier core-shell capsules to said
solubilising
medium comprises placing the carrier core-shell capsules inside a bath
comprising said
/5 liquid medium. The carrier core-shell capsules may simply be
transferred, for example
by dropping into said liquid medium.
In some embodiments, during said step of exposing said carrier core-shell
capsules to a
liquid medium, a substantial part of said carrier material is liquefied, for
example
20 dissolved, melted and/or suspended.
In some embodiments, during said step of exposing said carrier core-shell
capsules to
said solubilising medium, said carrier material diffuses through said shell to
the outside
of said capsules. In some embodiments, the liquid or solubilising medium may
diffuse
25 through said shell into the capsules. If an additive was added to the
medium, said
additive may diffuse into the capsules together with said liquid medium. In
particular,
said medium may comprise, consist essentially of or consist of said additive.
For
example, said liquid medium may be an essence, an essential oil, an extract,
for
example a plant extract, or any other type of liquid additive.
In some embodiments, said carrier core-shell capsules are exposed to said
solubilising
medium for a time that is sufficient to allow for diffusion or osmosis of a
substantial
part of said carrier material through said shell to the outside of said shell.
In some embodiments, said carrier core-shell capsules are exposed to said
liquid
and/or solubilising medium for a duration sufficient to at least partially
replace said
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carrier core of said core-shell capsules by said liquid medium, thereby
obtaining core-
shell capsules with a liquid core comprising said liquid medium. During this
step, a
substantial part of said carrier material moves by diffusion and/or osmosis
through
said shell to the outside of said shell. For example, more than 40 wt.%, more
than 50
wt.%, more than 60 wt.%, or 70 wt.% or more of said carrier material moves out
of said
carrier core-shell capsules. While it may, in some embodiments, be preferred
that
essentially all of the carrier material (up to loo wt.%) is removed from the
inside of the
capsules, it is generally observed that small or residual amounts of the
carrier material
remain within the capsules.
The solubilising medium, optionally comprising an additive, may move, for
example
diffuse to the inside of the shell at the same time while said carrier
material is moving
from the inside to the outside of said shell. In this event, a diffusional
exchange occurs
through the membrane of said shell of said carrier core-shell capsules. In
other words,
/5 at least a partial replacement of the carrier material by said
solubilising medium and/or
said additive takes place.
In accordance with the above said, in an aspect or an embodiment, the methods
of the
invention may be directed to methods of encapsulation and/or methods of
providing
core-shell capsules having an additive by counter-current flow diffusion
and/or
diffusional exchange.
Alternatively, it is envisaged that the carrier material moves and/or diffuses
outside in a
first step, and said solubilising medium and/or an additive moves and/or
diffuses to
the inside of the shell in a subsequent, separate step. It is also envisaged
that a separate
step is provided specifically for letting the additive, or a solution or
dispersion
containing it, into the shell, following a preceding step in which the carrier
material was
removed from the carrier core-shell capsules.
Furthermore, the invention also encompasses the embodiment in which the
additive is
present together with said carrier core and during exposure to the
solubilising medium
only or substantially only the carrier material diffuses out of the capsule
shell, while the
additive is retained within the shell.
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In some embodiments, by exposure of the carrier core-shell capsules to the
solubilising
medium, and/or to a medium comprising an additive, core-shell capsules
comprising a
liquid core and/or an additive are obtained.
In an embodiment, the methods of the invention comprise a step of removing
said core-
shell capsules with a liquid core, for example as obtained in the preceding
step, from
said solubilising and/or liquid medium. Conveniently, said capsules may be
separated
by filtration, for example.
io According to an embodiment, the methods of the invention comprise a step
of
removing residual liquid and/or solubilising medium and additive, if
applicable, from
the surface of said core-shell capsules by washing the capsules, for example.
It is also possible to dry the surface of the core-shell capsules as obtained
following the
/5 exposure to the medium and/or following the above, optional washing
step. In some
embodiments, said core-shell capsules are dried with air or a gas having an
appropriate
temperature, for example in an air and/or gas stream. Alternatively, or in
addition,
residual medium or solvent may be removed from the surface of said core-shall
capsules with the aid of an appropriate absorbing medium, such silicate
powder, for
20 example.
Optionally, the invention encompasses ways of further processing said
capsules, in
particular in order to adjust or modify the release characteristics and to
control the
release.
According to an embodiment, the methods of the invention may comprise the step
of
chemically and/or physically treating or processing said shell of said core-
shell capsules
comprising an additive so as to modify the diffusion properties through the
shell of said
core-shell capsules. If the method of the invention comprises a previous,
first step of
chemical and/or physical treatment, the present step may be a second step of
chemical
and/or physical treatment. This time, the capsules comprise an additive and
the carrier
core has been substantially removed.
Accordingly, the methods of the invention may comprise the step of exposing
said core-
shell capsules to conditions resulting in the change of the diffusion
characteristics of
the shell of the capsules obtained in the preceding step, so as to reduce the
capacity of
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the additive to diffuse through said shell and/or to the outside of the
capsules, once at
least part of the carrier core has been moved out of said shell.
In some embodiments, the treatment and/or processing of this step results in a
reduction of permeability of the membrane of the shell. This treatment may
result in a
better retention of the core comprising the additive within the shell.
Chemical and/or physical treatment for modifying permeability and/or diffusion
characteristics of the shell include, for example, exposure to a change of
temperatures
io (exposure to a higher and/or a lower temperature), exposure to pressure,
exposure to a
pH change, and/or applying a coating onto the core-shell capsules.
The methods of the invention may comprise the step of applying a coating on
said core-
shell capsules comprising an additive. This step may be conducted following
the step of
/5 exposing the cells to said liquid and/or solubilising medium, optionally
after an
intermediate washing step. At this stage, the core-shell capsules already
comprise, in
their core, the additive, and the carrier core may have been substantially
removed.
In embodiments in which the step of encapsulating said carrier beads involved
a
20 coating step, the step of coating core-shell capsules comprising the
additive may be
referred to as a second coating, while the former coating may be referred to
as a first
coating. Alternatively, the step of coating core-shell capsules comprising the
additive
may be referred to as an outer coating 34, while the former coating may be
referred to
as a shell 32.
Said chemical and/or physical treatment, for example said coating, may result
in a
change of the pore and/or permeability characteristics and in particular may
improve
the retention of the additive inside the capsules.
The solvent, such as acetic acid, in which the cellulose acetate is applied to
the carrier
structure to form the shell of the core-shell capsules may be removed. In some
embodiments, this removal of the solvent is by evaporation. This evaporation
may be
as a result of an evaporation step in which the capsules or their precursors
may be
exposed to conditions which encourage or enhance evaporation of the solvent
used.
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In some embodiments, if a second coating is performed, such coating may be
made by
way of any suitable film-forming and/or polymeric material. In some
embodiments, a
plasticiser is used. For example, said capsules may be coated with a substance
comprising, consisting essentially of or consisting of a lipid, for example a
wax and/or a
fat, a lacquer, and/or any other film-forming and/or polymeric material, such
as
cellulose acetate, cellulose acetate phthalate, cellulose triacetate, and/or
cellulose
derivatives such as hydroxypropyl methylcellulose (HPMC) and/or carboxymethyl
cellulose (CMC), for example. Other suitable plasticisers are discussed
elsewhere in this
specification.
Examples of suitable waxes include carnauba wax, bees wax, castor wax,
candellila wax
and paraffin wax. Examples of other lipids are hydrogenated oil, such as
hydrogenated
soybean or palm oil, mono glycerides, diglycerides, acetic acid esters, datem,
ascorbyl
palmitate, calcium stearate, magnesium stearate and potassium stearate, for
example.
The material of the second coating, second or subsequent layer, for example,
may be
chosen in dependence of the desired release characteristics. The stability,
integrity
and/or susceptibility of the second or subsequent coating/layer determine the
retention
and/or the release of the additive from the core, and may be selected
accordingly. If
release is to take place only after mechanical damage of the capsule, the
material for the
second or subsequent coating/layer may be selected so as to be relatively
stable with
respect to fluctuations of environmental parameters, such as the temperature
and/or
pH, for example. In addition, in this case the capsule material may be rigid,
resisting
little or not at all to mechanical constraints and/or pressure.
When the core of the capsule comprises water and/or a water-soluble material,
the
material of the second coating, second or subsequent layer may be impermeable
to
water and/or liposoluble. When the core of the capsule comprises a liposoluble
material, the material of the second coating, second or subsequent layer may
be
impermeable to fats and/or water-soluble.
Said first and second coatings or layers of the core-shell capsules of the
invention may
be made from the same or different layers.
The invention relates to a tobacco product comprising capsules that are
obtainable by
any one of the methods of the invention. Such tobacco products include smoking
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articles and smokeless oral tobacco products. Alternatively and/or in
addition, the
invention relates to a filter element comprising a core-shell capsule for a
smoking
article obtainable by any one of the methods of the invention. The core-shell
capsule(s)
may be incorporated into the tobacco product and/or filter element by any
suitable
method known in the art.
According to an embodiment, the invention provides a core-shell capsule
comprising a
core comprising an additive, wherein at least part of said core and/or said
additive has
properties of or comprises a liquid and/or at least part of said core and/or
said additive,
io is a liquid at 60 C, at 50 C, at 40 C, at 35 C and/or at 30 C, and/or at
room
temperatures (25 C), or at even lower temperatures, such as 22 C, 20 C, 15 C,
10 C
and 5 C.
According to an embodiment, at least a part of said core and/or said additive
has the
/5 properties of a liquid or comprises a liquid. In some embodiments,
substances that
comprise a liquid encompass compositions that comprise different substances
which
are present in different conditions of aggregation, respectively, at least one
substance
being present in the form of a liquid. For example, in some embodiments the
core
and/or additive may comprise a gel or a liquid that is mixed with a solid.
Examples of substances of matter that comprise a liquid and that may function
as an
additive and/or core of the capsules of the invention are a gel, a wet spongy
structure, a
suspension, an emulsion, a dispersion, a colloid, an aerosol and a foam.
Substances that have properties of a liquid, including liquids, are substances
that do
not resist strongly to a change of form, but which generally resist to
exposure of
pressure. Liquids can generally hardly be compressed. According to a general
definition, a liquid is a form of matter with a definite volume but no fixed
shape.
Examples of substances of matters that are not strictly liquids but which have
properties of a liquid and which may be used as at least part of the core
and/or additive
in the capsules of the invention may be selected from semi-solids, such as
liquid
crystals and plastic crystals. Semi-solids, or quasi-solids are also known as
amorphous
liquids.
According to an embodiment, a liquid, and a substance having the properties of
a liquid
(such as semi-solids) is a substance having a viscosity in the range of 0.005
to 15,000
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centipoises at 60 C, at 50 C, at 40 C, at 35 C and/or at 30 C, and/or at room
temperatures (25 C), or at even lower temperatures, such as 22 C, 20 C, 15 C,
10 C
and 5 C.
According to an embodiment, a liquid, and a substance having the properties of
a
liquid (such as semi-solids) is a substance having a viscosity in the range of
0.005 to
3,000 centipoises at 60 C, at 50 C, at 40 C, at 35 C and/or at 30 C, and/or at
room
temperatures (25 C), or at even lower temperatures, such as 22 C, 20 C, 15 C,
10 C
and 5 C.
According to an embodiment, a liquid, and a substance having the properties of
a liquid
(such as semi-solids) is a substance having a viscosity in the range of 0.005
to 1,000
centipoises at 60 C, at 50 C, at 40 C, at 35 C and/or at 30 C, and/or at room
temperatures (25 C), or at even lower temperatures, such as 22 C, 20 C, 15 C,
10 C
and 5 C.
According to an embodiment, a liquid, and a substance having the properties of
a liquid
(such as semi-solids) is a substance having a viscosity in the range of 0.005
to 500
centipoises at 60 C, at 50 C, at 40 C, at 35 C and/or at 30 C, and/or at room
temperatures (25 C), or at even lower temperatures, such as 22 C, 20 C, 15 C,
10 C
and 5 C.
According to an embodiment, a liquid, and a substance having the properties of
a liquid
(such as semi-solids) is a substance having a viscosity in the range of 0.005
to 200
centipoises at 60 C, at 50 C, at 40 C, at 35 C and/or at 30 C, and/or at room
temperatures (25 C), or at even lower temperatures, such as 22 C, 20 C, 15 C,
10 C
and 5 C.
Viscosity may be determined using a Brookfield DV-II+ viscometer on 0.50 mL of
sample at a temperature as specified above, (e.g. 60 C, 50 C, 40 C, 35 C, 30
C, 22 C,
20 C, 15 C, 10 C, 5 C, 25 C, as applicable).
According to an embodiment, in the above viscosity ranges expressed in
centipoises,
the value of 0.005 is replaced by 0.899 centipoises, which is the viscosity of
water.
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In some embodiments, at least part of said core, for example at least 50 wt.%,
at least
60 wt.% or at least 70 wt.%, 80 wt.% and/or 90 wt.% of said core remains
liquid and/or
keeps the liquid properties during a shelf life of three months when stored at
25 C and
at a relative humidity of 50%.
In some embodiments, at least part of said core, for example at least 50 wt.%,
at least
60 wt.% or at least 70 wt.%, 80 wt.% and/or 90 wt.% of said core remains
liquid and/or
keeps the liquid properties during a shelf life of six months when stored at
25 C and at
a relative humidity of 5o%.
In some embodiments, at least part of said core, for example at least 50 wt.%,
at least
60 wt.% or at least 70 wt.%, 80 wt.% and/or 90 wt.% of said core remains
liquid and/or
keeps the liquid properties during a shelf life of nine months when stored at
25 C and
at a relative humidity of 5o%.
In some embodiments, the core of said core-shell capsules comprises residual
and
detectable amounts of said carrier material. For example, if said carrier
material is
PEG, said core may comprise residual PEG, in addition to the additive.
In some embodiments, the shell of said core-shell capsules comprises cellulose
acetate
and/or a derivative thereof, such as cellulose acetate phthalate, for example.
Other shell
materials are mentioned elsewhere in this specification.
In some embodiments, the shell of said core-shell capsules is multi-layered,
comprising
at least two, or at least three or more distinguishable layers. Said different
layers may
comprise and/or consist of different materials and/or different compositions.
The first
layer may be referred to as the shell 32, and any subsequent layers may be
referred to as
coatings 34.
Examples
The following examples are provided to assist in the understanding of the
invention and
are not intended to limit the scope of the invention.
Example 1: Preparation of a support and additive core
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Polyethylene glycol (PEG) 2000 having a melting point of 45-50 C (Merck,
Germany)
was melted and maintained at a temperature of 60-65 C. 15 wt.% of menthol oil
was
mixed with the PEG.
A cooling bath was prepared with sunflower oil and kept at 10-15 C. The PEG-
menthol
mixture was extruded through a nozzle of 1400 lam (Nisco, Zurich, Switzerland)
and
dropped in a drop-wise manner in the cooling bath.
Beads with a diameter of 2-4 mm were harvested with a sieve from the cooling
bath and
io washed with acetone.
Example 2: Formation of a shell
g cellulose acetate (Sigma Aldrich , CAS no. 9004-35-7) was dissolved in loo
ml
acetic acid. Once the cellulose acetate was completely dissolved, 80 ml
isopropanol was
/5 added progressively to the solution. The beads with the core structure
of Example 1
were coated in a fluidized bed (MP-1, Aeromatic, Niro, Germany) by atomization
of the
cellulose acetate solution, with a weight ratio of 90% beads to 10% cellulose
acetate.
Example 3: Replacement of carrier substrate from core
The coated beads of Example 2 were put in a water bath of 70 C and kept
therein until
liquefaction of the core and absorption of water in the core.
Example 4: Wax-sealing of the coated capsules with liquid core
A proportion of the capsules comprising a shell and a liquid core of Example 3
were
coated with castor wax in a fluidized bed (same apparatus as in Example 2), up
to a
weight ratio of 5% wax and 95% capsules.
Example 5: Cellulose acetate-sealing of the coated capsules with liquid core
The remaining proportion of the capsules of Example 3 were fluidized-bed
coated with
cellulose acetate instead of wax. In particular, 15 g cellulose acetate was
dissolved in
loo ml acetic acid. Once the cellulose acetate was completely dissolved, 80 ml
isopropanol was added progressively to the solution.
The capsules obtained in Examples 4 and 5 were stored for 6 months at 25 C at
a
relative humidity (rH) of 70. Upon rupturing individual capsules, the liquid
content of
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the capsules was released. The additive remained liquid in the capsules during
the 6
months.
Example 6: Preparation of a support and additive core
PEG 3000 (melting point of 50-56 C) and PEG 1500 (melting point 42-48 C) in
80/20
proportion was melted and maintained at a temperature of 65-70 C. 15 wt.% of
menthol oil was mixed with the PEG mixture. Beads with a diameter of 2-4 mm
were
prepared and washed as described in Example 1.
io Example 7: Formation of a shell
g cellulose phthalate (cellulose acetate phthalate, Sigma Aldrich , CAS no.
9004-38-
o) was dissolved in loo ml acetic acid. Once the cellulose phthalate was
completely
dissolved, 80 ml isopropanol was added progressively to the solution. The
beads with
the core structure of Example 6 were coated in a fluidized bed by atomization
of the
/5 cellulose phthalate solution, with a weight ratio of 90% beads to 10%
cellulose
phthalate.
Example 8: Replacement of carrier substrate from core
The coated beads of Example 7 were put in a water bath of 70 C and kept
therein until
liquefaction of the core and absorption of water in the core.
Example 9: Wax-sealing of the coated capsules with liquid core
A proportion of the capsules comprising a shell and a liquid core of Example 3
were
coated with a mixture of waxes in a fluidized bed, up to a weight ratio of 5%
wax and
95% capsules. The wax mixture was composed of 33.3% bees wax, 33.3% castor wax
and 33.3% carnauba wax, which waxes were melted in a mixture and sprayed on
the
capsules.
Example 10: Cellulose phthalate-sealing of the coated capsules with liquid
core
The remaining proportion of the capsules of Example 8 were fluidized-bed
coated with
cellulose phthalate instead of wax. 15 g cellulose phthalate was dissolved in
loo ml
acetic acid. Once the cellulose phthalate was completely dissolved, 80 ml
isopropanol
was added progressively to the solution.
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The capsules obtained in Examples 9 and 10 were stored for 6 months. Upon
rupturing
30 individual capsules, the liquid content of the capsules was released. The
additive
remained dispersed in the capsules during the 6 months.
Example ii: Preparation of a support and additive core
PEG 2000 (melting point of 45-50 C) is melted and maintained at a temperature
of 60-
65 C. 15 wt.% of menthol oil is mixed with the PEG.
A cooling bath is prepared with sunflower oil and kept at 10-15 C. The PEG-
menthol
io mixture is extruded through a nozzle of 500 lam and dropped in a drop-
wise manner
into the cooling bath.
Beads with a diameter of 1-2 mm are harvested with a sieve from the cooling
bath and
washed with acetone.
Example 12: Formation of a shell
The beads with the core structure of Example 11 are coated with a weight ratio
of 90%
beads to 10% cellulose acetate exactly as discussed in Example 2.
Example 13: Replacement of carrier substrate from core
The coated beads of Example 12 are put in a water bath of 70 C and kept
therein until
liquefaction of the core and absorption of water into the core.
Example 14: Fat-sealing of the coated capsules with liquid core
A proportion of the capsules comprising a shell and a liquid core of Example
13 are
coated with fat in a fluidized bed, up to a weight ratio of 5% fat and 95%
capsules. The
fat used is Bergazid fat (C1852, from Berg and Schmidt, Hamburg, Germany),
which is
melted and sprayed on the capsules.
Example 15: Cellulose acetate-sealing of the coated capsules with liquid core
The remaining proportion of the capsules of Example 13 are fluidized-bed
coated with
cellulose acetate as discussed in Example 5.
The capsules obtained in Examples 14 and 15 are stored for 6 months at 25 C at
70%
rH. Upon rupturing individual capsules, the liquid content of the capsules is
released.
The additive remains liquid in the capsules for up to 6 months.
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Example 16: Preparation of a support and additive core
A mixture of PEG 3000 (melting point of 50-56 C) and PEG 1500 (melting point
42-
48 C) in 80/20 proportion was melted and maintained at a temperature of 65-70
C. No
additive was added at this stage. Beads with a diameter of 2-4 mm were
prepared and
washed as discussed in Example 1.
Example 17: Formation of a shell
The beads with the core structure of Example 16 were coated in a fluidized bed
with
io cellulose phthalate as discussed in Example 7.
Example 18: Replacement of carrier substrate from core
The coated beads of Example 17 were put in a emulsion bath of 60 C composed of
water
90% w/w, menthol oil 8% w/w, tween 20 1.5% w/w, Span 40 o.5% w/w and kept
/5 therein until liquefaction of the core and absorption of the emulsion
into the core.
Example 19: Wax-sealing of the coated capsules with liquid core
A proportion of the capsules comprising a shell and a liquid core of Example
18 were
coated with a wax mixture as used in Example 9 in a fluidized bed, up to a
weight ratio
20 of 5% wax and 95% capsules.
Example 20: Cellulose phthalate-sealing of the coated capsules with liquid
core
The remaining proportion of the capsules of Example 18 were fluidized-bed
coated with
cellulose phthalate as discussed in Example 10.
The capsules obtained in Examples 19 and 20 were stored for 12 months at 70%
rH, at
room temperature. Upon rupturing individual capsules, the liquid content of
the
capsules was released. The additive remained dispersed in the capsules during
the
storage period.
Example 21: Preparation of a support and additive core
Beads with a diameter of 2-4 mm were prepared and washed as discussed in
Example
16.
Example 22: Formation of a shell
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The beads with the core structure of Example 21 were fluidized-bed coated with
cellulose phthalate solution as discussed in Example 7.
Example 23: Replacement of carrier substrate from core
The coated beads of Example 22 were put in a flavour bath of 60 C composed of
thyme
essential oil and kept therein until liquefaction of the core and absorption
of the flavour
in the core.
Example 24: Wax-sealing of the coated capsules with liquid core
/o A proportion of the capsules comprising a shell and a liquid core of
Example 23 were
coated with the wax mixture discussed in Example 9 in a fluidized bed.
Example 25: Cellulose phthalate-sealing of the coated capsules with liquid
core
The remaining proportion of the capsules of Example 23 were fluidized-bed
coated with
/5 cellulose phthalate as discussed in Example 10.
The capsules obtained in Examples 24 and 25 were stored for 12 months at 70%
rH, at
room temperature. Upon rupturing individual capsules, the liquid content of
the
capsules was released. The additive remained dispersed in the capsules for up
to 12
20 months.
Example 26: Uncoated capsules with cellulose acetate shell and additive core
A cellulose acetate core-shell capsule was produced with the following
composition:
5% cellulose acetate
25 5% PEG 400
80% PEG 1500
15% menthol oil
Example 27: Preparation of a further support core
PEG 3000 and PEG 400 were mixed at a weight ratio of 85% to 15% to achieve a
melting point of 45-50 C. The mixture was melted and maintained at a
temperature of
6o-65 C. The melted PEG was extruded into a cooling bath as described in
Example 1
and capsules with an average diameter of 2-4 mm were harvested with a sieve
from the
cooling bath and washed with acetone.
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Example 28: Formation of a shell with cellulose acetate
The capsules with the core structure of Example 27 were coated as described in
Example 2, with a weight ratio of 90% capsules to 10% cellulose acetate.
Example 29: Formation of a different shell with cellulose triacetate
g cellulose triacetate (Sigma Aldrich, CAS no. 9012-09-3) was dissolved in 200
ml
acetic acid. Once the cellulose triacetate was completely dissolved, the
capsules with the
/0 core structure of Example 27 were coated in a fluidized bed by
atomization (see
Example 2) of the cellulose triacetate solution, with a weight ratio of 90%
capsules to
10% cellulose triacetate.
Example 3o: Replacement of carrier substrate from core
The coated capsules of Example 28 and 29 were put in a water bath at 35 C and
kept
therein until liquefaction of the core and diffusion of water into the core.
In this
example, water alone is used as the active agent.
Examples 31 to 4o: Sealing of core-shell capsules of Example 30
In a series of experiments, the liquid core-shell capsules of Example 30 (with
both types
of coatings) were subjected to a further treatment for sealing the shell and
making it
impermeable to the water (the encapsulate) retained within the shell of the
capsule. In
these further examples, the coating material, or a mixture of a coating
material and
plasticiser, were dissolved in one or two solvents and the capsules of Example
30 were
coated in a fluidized bed (MP-1, Aeromatic, Niro, Swiss) by atomization. Table
1 below
lists the details in terms of the sealing materials, plasticisers, solvents
used and
quantity.
In these examples, the sealing provides a second coating and/or a further
layer on the
shell of said core-shell capsules.
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Table 1: Solvents and coating materials for Examples 31 to 40
Ex. Solv. 1 Coating Amount Solv. Plasticiser Amount Weight
no. (ml) material coating 2 (ml) plasticiser
ratio*
material (g)
(g)
31 100 A 15 8o - - 95:5
32 200 B 15 - - - 95:5
33 loo A 15 8o C 12.5 89:6:5
34 200 B 15 - C 12.5 89:6:5
35 loo A 15 8o D 12.5 89:6:5
36 200 B 15 - D 12.5 89:6:5
37 loo A 15 8o E 12.5 89:6:5
38 200 B 15 - E 12.5 89:6:5
39 loo A 15 8o F 12.5 89:6:5
40 200 B 15 - F 12.5 89:6:5
Solv. 1: acetic acid; Solv. 2: isopropanol;
*weight ratio of core-shell capsules obtained in Example 30: coating material
(Examples 31 and 32) or core-shell capsules obtained in Example 3o:
plasticiser
(Examples 33-40);
Coating materials: A = cellulose acetate; B = cellulose triacetate;
Plasticisers: C = benzyl benzoate; D = triacetin; E = triethyl citrate; F =
dibutyl
phthalate.
io For instance, Example 34 was conducted as follows: 15 g cellulose
triacetate was
dissolved in 200 ml acetic acid. Once completely dissolved, 12.5 g of benzyl
benzoate
plasticiser was added progressively to the solution. It is noted that
cellulose triacetate is
not compatible with isopropanol, which is why the dilution of acetic acid with
isopropanol is not conducted in this example. The liquid core-shell capsules
of Example
30 were coated in a fluidized bed by atomization of the cellulose triacetate
solution,
with a weight ratio of 89% core-shell capsules (Example 30), 6% cellulose
triacetate
and 5% benzyl benzoate (11% of second coating altogether).
In Examples 33, 35, 37 and 39, isopropanol was added progressively to the
solution of
the first solvent and the coating material. Then, the plasticiser was added to
the
solution comprising the two solvents and the coating material dissolved
therein. Then,
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the capsules of Example 30 were coated using the mixture of solvents, coating
material
and plasticiser as described above. Example 31 was conducted as Example 2.
In Examples 31 to 40 sealed core-shell capsules or core-shell capsules
comprising two
separate coatings (multi-layer core-shell capsules) were obtained. The
capsules were
stored for 6 months at 25 C at a relative humidity (rH) of 75%. Upon rupturing
individual capsules, the liquid content of the capsules was released. The
water
remained inside the capsules during the 6 months.
/0 In order to address various issues and advance the aft, the entirety of
this disclosure
shows by way of illustration various embodiments in which the claimed
invention(s)
may be practiced and provide for superior containment of additive. The
advantages and
features of the disclosure are of a representative sample of embodiments only,
and are
not exhaustive and/or exclusive. They are presented only to assist in
understanding and
/5 teach the claimed features. It is to be understood that advantages,
embodiments,
examples, functions, features, structures, and/or other aspects of the
disclosure are not
to be considered limitations on the disclosure as defined by the claims or
limitations on
equivalents to the claims, and that other embodiments may be utilised and
modifications may be made without departing from the scope and/or spirit of
the
20 disclosure. Various embodiments may suitably comprise, consist of, or
consist
essentially of, various combinations of the disclosed elements, components,
features,
parts, steps, means, etc. In addition, the disclosure includes other
inventions not
presently claimed, but which may be claimed in future.
