Note: Descriptions are shown in the official language in which they were submitted.
P~ckagin~ Smoking Materials
This invention relates to packaging
arrangements for smoking materials, particularly
tobacco for pipe and hand-rolling consumption but also
has application in other packaged -tobacco products
such as cigars.
Such tobacco is usually sold in generally
air-tight, fixed weight packages and normally includes
a number of volatile components such as water,
flavouring materials and some preservatives. The
water provides beneficial tactile properties which
assists the consumer in end use, for example the
hand-rolling of cigarettes, and influences smoking
quality.
Currently, hand-rolling tobacco is packaged
and sold at high moisture content compared to the
tobacco in manufactured cigarettes in order to satisfy
the consumer's requirements. This moisture content is
generally greater than about 18~ which results in a
distinc-t disadvantage for the tobacco producer
because, at such high values, tobacco becomes
susceptible to mould cultures and requires precautions
during manufacture. These precautions include the use
of preservatives to inhibit mould growth and strict
rotation of tobacco stock. The shelf life of the
product may nevertheless be reduced.
Susceptibility to mould growth decreases
rapidly below 18~ moisture content.
The prior art discloses humidification and
humidistat devices for inclusion in the package or as
3 an integral part of the packaging associated with
tobacco and food products, for example, US 1 871 419
discloses a humidifying sheet using a hydrated salt, a
fibrous substrate and a vapour permeable membrane.
US 2 ~52 957 discloses a vapour permeable rnembrane of
regenerated cellulose film enclosing an efflorescent
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salt and GB 1 369 992 discloses a humidistat
comprising a pad containing a buffer solution enclosed
in an envelope of vapour permeable thermo-plastic
material. US 3 801 011 discloses water containing
microcapsules with vapour-transmitting walls.
~ ore recently US 4 997 082 and US 5 037 459
have disclosed improvements to humidistat systems but,
as far as is known to the applicants, the prior art
has not recognised the benefits of a delayed action,
self actuating humidistat or humidification system
which is used to add water and, if desired, other
volatile materials to tobacco or tobacco products
after packing.
According to the present invention there is
provided an arrangement comprising a generally air
tight package and a smoking material/product contained
therein, said arrangement incorporating self-actuating
moisturising means adapted to release moisturising
fluid thereby to increase the moisture content of the
smoking material/product after a substantially
predetermined period of time subsequent to packing.
Preferably the moisturising means comprises a
liquid impermeable reactive membrane which encloses a
pad containing the fluid contents of the moisturising
means. In some arrangements the membrane decomposes
or dissolves over said predetermined period thereby to
become permeable and to release the moisturising fluid
to the package.
Ideally there is also provided a vapour
3 permeable, liquid barrier which permits transfer of
moisturising fluid in the vapour phase only to the
package contents. This is because it is desirable to
prevent localised concentrations of liquid phase
reaching or "wicking" into the -tobacco or packaging
material.
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In some chosen arrangements the liquid barrier
and the reactive membrane are formed as a coated film
or laminate with the impermeable reactive membrane in
contac-t with the moisturising fluid and with the
liquid barrier in contact with the package contents.
A further feature is that the moisturising means
comprises a plurality of moisturising elements and
each element is adapted to release moisture after
different periods of time. This allows reconditioning
of the tobacco over an extended period of time.
Preferably said moisturising fluid comprises water and
said fluid also comprises other volatile materials
including flavourants and/or preservatives and/or
additives.
In other arrangements the moisturising fluid
comprises a saturated salt solution. In one
embodiment the salt solution is of sodium chloride
adapted to achieve an equilibrium relative humidity of
a predetermined value in the packaged environment.
Preferably the relative humidity is about 75%, this
relative humidity being compatible with the tobacco
moisture that is preferred by the consumer for hand-
rolling use. In further embodiments the self
actuating moisturising means comprises hygroscopic
material separated from the smoking material/product
by a vapour permeable liquid barrier the hygroscopic
material in turn being separated from a moisture
source by a further vapour permeable liquid barrier.
Conveniently the hygroscopic material is a polyol such
3 as glycerol.
Embodiments of the invention will now be
described in more detail by reference to the
accompanying diagrammatic drawings in which:
Figure 1 shows a partially cut-away
perspective view of a tobacco pouch according to the
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present invention,
Figure 2 shows a cross-section through the
tobacco pouch shown in figure 1,
Figure 3 shows an exploded perspective of an
alternative arrangement for the containment of
moisturising liquid,
Figure 4 shows a sectional view through a
further arrangement according to the present
invention, and
Figure 5 shows a sectional view through a
still further arrangement.
Referring to figures 1 and 2, there is shown a
tobacco pouch 10 containing tobacco 11. The pouch 10
has a conventional closure flap 12 and incorporates a
moisturising element 13 comprising a fibrous absorbent
pad containing a measured quantity of water. There
is the possibility of also including other volatile
additives/flavours and bufering compounds (eg
glycerol) according to particular requirements. The
moisturising element 13 is located adjacent to and
sealed against an inner surface of the pouch 10 by
means of a vapour permeable liquid barrier 14 which
lies adjacent to the tobacco 11. The liquid barrier
14 comprises a laminated or coated film material which
has an outer, vapour permeable surface 15 in contact
with the tobacco which surface 15 is a permanent
liquid barrier and an inner, degradable liquid barrier
16 in contact with the moisturising pad, which barrier
16 after a time becomes liquid permeable. The vapour
3 permeable surface 15 is for example a regenerated
cellulose film which may be coated or partially coated
with the liquid barrier 16 as a lacquer or laminate.
The material of the barrier 16 is chosen to react with
the liquid contents of the element 13 such that its
liquid barrier properties diminish during storage
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whereby after a predetermined period the barrier 16
becomes liquid permeable. The moisturising liquid is
then released as a vapour through the vapour permeable
surface 15 to the contents ll of the pouch.
In the figure 3 arrangement there is a fibrous
pad 17 and a single or multiplicity of liquid
containers 1~ such as sachets constructed of a
degradable liquid impermeable film. There is a vapour
permeable liquid barrier l9 enclosing these components
and sealing them from the tobacco material ll. It
will be appreciated that the containers 18 could even
be designed so as to degrade at different times or to
contain different volatiles for release at different
times.
In an alternative embodiment shown in figure 4
the pad 13 containing a measured quantity of chosen
fluids is sealingly enclosed adjacent the pouch lO by
a laminated membrane 20 having inner and outer layers
21, 22 of vapour permeable material such as cellulose
film which layers 21, 22 are laminated with a layer in
between. These layers 21, 22 may also include agents
for modifying the permeability to water vapour, e.g. a
nitrocellulose coating. The middle layer essentially
comprisesa polyol e.g. glycerol, such that at low
moisture content it is hygroscopic yet at higher
moisture content the vapour pressure of water above
the polyol/water system is sufficient to enable a high
rate of transfer of moisture to the tobacco article.
This inner matrix acts initially as an absorber of
3 water from the pad 13 and after an in-terval, dependent
upon the composition, acts as an emitter of water.
The overall driving force being the reservoir of
water, the uptake by -the tobacco article being quasi
exponential. It will, of course, be apparent that the
timing of the release of moisture to the tobacco can
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be varied by careful choice of the absorbent
hygroscopic layer and the permeability of the layers
21, 22.
The amount of water contained by the device
must be chosen to suit the end product application
such that the desired moisture content of the tobacco
can be achieved. By way of example, hand-rolling
tobaccos tend to achieve the desired moisture content
at about 75% Relative Humidity leading to a moisture
10 content of about 25-30~ in the tobacco. 3g of water
is required to raise 25g of hand rolling tobacco from
18% moisture to 27~.
Another example of a suitable construction is
a sandwich comprising two outer cellulose fi~ms
enclosing a fibrous cellulose pad containing glycerol.
In figure 5 there is shown an arrangement very
similar to that shown in figure 4. The difference is
that the barrier layer is not formed as a laminated
structure with the cellulose layers 21, 22. In figure
5 the polyo] is held in a fibrous cellulose pad 25
which is retained between the two layers 21, 22. The
operation is, however, the same as that of the figure
4 arrangement.
The above refers to packaging and moisture
addition to tobacco but it will be appreciated that
other tobacco products and smoking materials including
substitutes cigars and cigarettes could be used.
The tobacco can thus be packed at a lower
moisture than is desired for use so that mould growth
is reduced between packaging and consumption. The
resistance to mould and control over molsturising
provides increased shelf-life.
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