Note: Descriptions are shown in the official language in which they were submitted.
~3~3~
METHOD OF PRODUCING A NON-BURNI~G OUTER
WRAPPE~ FOR USE WITH Sl\IOKING PRODUCTS
E~[~
The invention relates to a method for producing a non-burning
wrapper for use with smoking products. More specifically, this invention
relates to a method for producing a non-burning cigarette wrapper using a
treating solution contai~ning calcium chloride, a reactive size for paper, and acoating solution containing calcium carbonate, potassium silicate and
sodium carboxymethylcellulose.
One of the more recent developnents in the field of cigarette
technology involves cigarettes which contain a non-tobacco fuel source
which typically heats tobacco contained within a cigarette.
One problem encountered in producing such cigarettes is the
availability of a suitable wrapper. The burning of tobacco in conventional
cigarrettes masks the odor of the burning wrapper used in conventional
cigarettes Because non-tobacco fueled cigarettes have little or no odor
attributable to the combustion of the fuel element or tobacco, any odor
resulting fro n the burning of the wrapper is highly noticeable. A suitable
~rrapper must, tnerefore, ernit little if any aroma or smoke upon ignition of
the cigarette, have the appearance of a conventional cigarelte and provide
adequate suppor~, once tne cigarette is lit tc, contain the fuel source within tne
cigarette.
It is known in the art to add burn control agentr. to paper used
with smoking products to control burn rate, ash formation and side stream
smoke emission. These agents may act to either retard or accelerate the burn
rate of the paper. However, even though burn rate is controlled, paper
~reated with such burn control agents generally burns unless large amounts
S of burn control agents are added. This burning produces an unpleasant
odor and transfo~ns the cellulose into a non-cellulose ash. Alternatively,
paper trested with large amounts of burn control agents is trans~ormed by
the heat into a cellulose char, and the emission of appreciable odor and
smoke is elirninated. However, the char produced is typically a black or an
aesthetically unacceptable dark color.
United States Patent No. 4,453,553, teaches a wrapper treated
with a burn retarding compound which produces a light grey or white ash.
This wrapper is not acceptable because it burns emitting an odor and
folming an ash which does not possess sufficient strength to contain the
lS fuel source within the cigarette.
Another example is disclosed in United States Patent No.
4,779,631. This wrapper, has the disadvantage of providing a non-uniform
}ength of ash, the length of which varies with the puffing strength of the
smoker, produces an aroma which is irritating and detrimental to roorn
aroma, and does not provide unifolm delivery to the smoker.
Thus, a need exists in the art for a wrapper for use with
smoking products which does not produce a noticeable aroma, does not
burn out to form an ash incapable of con~aining the fuel source, and does
not produce a variable length char or char having an aesthetically
unacceptable color, and which provides uniform delivery to the smolcer.
The present invention solves the above-describecl need by
providing a method of producing a non-burning cigarette wrapper which
does not impart a significant aroma, forms a white or gray char capable of
containing the fuel source, provides unifolm delivery to the smoker and is
less sensitive to differences in heat generated by the fuel source.
Generally described, the method of this invention comprises the
steps of forming a treating solution consisting essenhally of water, calcium
chloride and a reactive size for paper; treating both sides of a base paper
3 ~ ~
with the treating solution; drying the thus treated paper, forming a coating
solution consisting essentially of water, calcium carbonate, potassium
silicate, and sodium carboxymethylcellulose; coating one side of the ~hus
treated paper with the coating solution; and drying the thus treated and
coa~ed paper to form a non-burning wrapper for use with smoking
products.
The preferred method of this invention comprises the steps of
forming an aqueous treating solution having between 9% and 18% by
weight calcium chloride solids and between 0.2% and 2.0% by weight
reactive size; treating both sides of a base paper having an untreated
permeability of between 200 and 6500 cm/min (determined in accordance
with the CORESTA perrneability determina~ion method) with the treating
solution such that the base paper contains calcium chloride in an amount
between 6% and 14% by weight of the treated paper and reactive size for
paper in an amount between 0.1% and 1.5% by weight of the treated paper,
forrning an aqueous coating solution having between 2% and ~% by weight
calcium carbonate solids, between 1% and 5% by weight potassium silicate
solids, and between û.3% and 2.5% by weight sodium carboxymethyl
cellulose solids; coating one side of the ~hus treated paper with the coating
solution such that the paper contains calcium carbonate in an amount
between 3% and 10% by weight of the finished wrapper, potassium silicate
in an amount between 2% and 6% by weight of the finished wrapper and
sodiurn carboxymethylcellulose in an amount between 0.3~o and 1.5% by
weight of the finished wrapper and drying the thus treated and coated paper
to form a finished non-burning wrapper for use with smoking products.
Accordingly, an object of the invention is to provide a method
for producing a non-burning wrapper for use with smoking products.
A further object is to provide a non-burning wrapper ~or use
with cigarettes which contain a non-tobacco fuel source.
Yet another object of the invention is to provide a non-buming
wrapper for cigarettes which does not impart a significant aroma, forms a
white or grey char capable of containing the fuel source, provides uniform
delivery to the smoker, and is not sensitive to differences in heat generated
by the fuel source.
~ '3'~
... C .~
In a preferred embodiment, the method of this inventiQn
comprises the following steps. First, an aqueous treating solution is folmed
having between 9% and 18% by weight calcium chloride solids and
S betwecn û.2% and 2.0% by wei~ht reac~ive size, preferably ~'Hercon 70"
available from Hercules, Inc. of Wilmington, Delaware; next, using
conventional saturation methods, such as a size press, the treating solution
is applied to both sides of a base paper, the base paper preferably being
100% cellulose paper and having a permeabili~y between 2ûO and 6500
cmJmin as determined in accordance with the CORESTA permeability
determination method. The thus treated paper is then dried using a standard
drying method. Using this solution and a standa~d saturation meth~, a
treated paper containing calcium chloride in an amount between 6% and
14% by weight of the ~eated paper and reactive size in an amoun~ between
0.1% and 1.5% by weight of the treated paper is formed. These
percentages may bç deterrnined by wet pick-up or by any standard method
for detecting chloride or calcium ions. It is necessary that a homogeneous
treating solution is formed, since application of the calcium chloride to the
base paper prior to application of the reactive size adversely affects the
subsequent step by allowing the reactive size to fo~l a barrier between the
calcium chloride and the po~assium silicate added in the next step.
Continuing with the process, an aqueous coating solution is
folmed having between 2% and 8% by weight calcium carbonate,
preferably "Albacar 5970," available from P~lzer & Co., Inc. of New York,
New York; between 1% and 5% by weight potassium silicate solids,
preferably "Kasil #l" available from Philadelphia Quartz Co. of
Philadelphia, Pennsylvania; and between 0.3% and 2.5% by weight sodiurn
carboxymethylcellulose solids, an example being "7H3S~' available from
Aqualon, a division of E~ercules, Inc. Using a standard coater with a
Mayer rod set up, the coating solution is applied to one side of the above
treated base paper. Using this solution and application method, a finished
wrapper containing calcium carbonate in an amount betwe n 3% and 10%
by weight of the fimished wrapper, potassium silicate in an amount between
2% and 6% by weight of ~he finished wrapper, and sodium
carboxyrnethylcellulose in an amount between 0.3% and 1.5% by weigh~ of
3~
the fimished wrapper is obtained.
In preparing the coating solution, the following procedure is
believed to produce the best results:
~1) Thoroughly mix the water and the calcium carbonate
such that the calcium carbonate is fully dispersed before adding the
potassium silicate;
~2) Add the potassi~n silicate and mix thoroughly;
(3) Add the sodium carboxymethylcellulose and mix
thoroughly. If sodium caTboxymethylcellulcse is added directly to the
calcium carbonate, dispersion will be inhibited.
The final step in making a non-burning paper for use with
cigaret~es is to dry the thus treated and coated ~eated paper.
Additionally, while the preferred embodiment discloses the use
of calcium carbonate, other fillers such as titanium dioxide and magnesium
dioxide may be utilized.
The method of this inven~ion provides a novel cigarette wrapper
which does not burn so as to forrn an ash, but chars, such that it still
contains cellulose, to an aesthetically pleasing gray color resembling
conventional cigarette ash. The cigarette wrapper does not emit noxious or
unpleasant odors when lit and provides a char strong enough to hold the
fuel source of the cigarette in place.
Another feature of the present invention is the vari~ble
perrneability of the wrapper. To provide a cigarette which is easily lit, it is
important to provide a low perrneability wrapper so that during lighting
2S most of the air is pulled through the end of the cigarette at the fuel source.
Once the cigarette is lit, however, it is preferable to have paper of higher
permeability so that rnore air is drawn through the wrapper to provide
adequate air delivery with each puff. The wrapper of the present invention
provides this versatility by having a coa~ing which reduces tne permeability
of the paper from between 30% to 80% for lighting the cigarette. Once the
char is fo~ned ~he coating degrades to provide a char area having
approxirnately the same penneability as the original uncoated wrapper.
An example of the effect of the coating on permeability is se~
forth below:
Base Sheet PermeabilityCoated Sheet Permeability
6~00 1670
~5~0 1 120
2700 3~4
500 190
The foregoing description relates to celtain embodiments of the
present inv~ntion, and modifications or alterations may be made without
departing from the spirit and scope of the inventoF as defined in the
following claims.
