Note: Descriptions are shown in the official language in which they were submitted.
WO92/05713 PCI/US91tO7109
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A ~R~N~ION FOR lCql:'m;Vhl~ DELI~tEP~Y O~
TOBACCO MODIFYING AGENTS
Field of the Invention
This invention concerns certain f ibers in
combination with tobacco modifying andior selective
removal agents.
Back~round of the Invention
Many types of tobacco modifying agents are known in
the art to be added to smoking products to modify the
tobacco smoke. For example, flavorants are added to
6moking products to enhance their taste and to
compensate for variations in tobacco quality and blena.
Although flavorants are traditionally applied to the
tobacco portion of the smoking product, this practice
results in only a small fraction of the flavorant ever
reaching the smoker. Most of a flavorant added to the
tobacco is lost in the sidestream smoke produced during
the static burn period of the smoking article or is
removed by the smoke filter. The low flavorant delivery
efficiencies associated with application on tobacco
necessitates the use of relatively large quantities of
flavorant to achieve the desired effect. Because many
of these flavorants, such as menthol, for example, are
expensive, inefficient utilization can add significantly
to the cost of the smoking product. In addition,
~, flavorants applied to the tobacco are subjected to the
high heat of combustion which can undesirably alter
their organoleptic characteristics.
In response to these problems, there has been
substantial effort to apply flavorants to the filter.
It was 6hown many years ago that smoke aerosols could
tran6port signif icant quantities of relatively non-
volatile materials from a structure of moderate surface
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2092176 ~
,~ ,
f ` -- 2 --
-.
area, even though a gas at a comparable t~ Lur e is
ineffective in this regard. Attempts at the practical
implementation of this rhf~nl using celiulose
acetate filters revealed, however, that although r
aerosols transported flavorant very efficiently from
freshly made filters, this advantage was lost as the
flavoran~ diffused away from the surface and into the
bulk of the f ilter f ibers .
Efforts to solve this problem by using polymers
impermeable to the flavorants, such as polypropylene,
eliminated the time d~rpn~nre of f lavorant delivery
observed with cellulose acetate filters, but did not
permit the development of a functional flavorant
delivery system. The causes of this failure were,
f irst, the f lavorant deIivery ef f iciencies f or these
nonpermeable polymer systems were too low to be useful,
and second, impermeable f ilter media had no af f inity f or
-the flavorant which consequently diffused to the tobacco
where it endured the same fate as flavorants applied
2 0 directly to the tobacco .
- In spite of years of concerted effort, neither the
cigarette noF the filter material industry has developed
an efficient general flavorant delivery system that does
not absorb or loose the f lavorant over time .
Prior art of this area reflects a strong interest
in technology for the efficient and consistent deliver
of tobacco modifying agents, especially flavorants.
~owever, the abundant patented technologies f or
flavorant delivery almost invariably employ one of the J
following four strategies:
l. A flavorant is contained by some physical means and
is released either by mechanlcal destruction of the
containment apparatus~ or by controlled leakage
(see, f~r example, I~.S. Patents 3,219,041;
3~ 3,297,038,; 3,339,557; and 4,720,423~.
., . ,, ~-,
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2 . A f lavorant is adsorbed on a material whose surf ace
has been customized so that the flavorant will be
displaced by the moisture or heat in the smoke
(see, for example, U.S. Patents 3,236,244;
3,280,823; and 4,662,384).
3 . A f lavorant is absorbed in a polymeric matrix and
is then released by the plasticizing action of
moisture or heat in the smoke ( see, f or example,
U.S. Patents 4,662,384; 3,144,024; and 4,729,391).
A portion of the prior art in this area addresses
the concept of modifying the fiber shape or filter
geometry of current cellulose acetate f ilters to
achieve improved flavorant containment or delivery
(see, for example, U.S. Patents 4,180,536,
4,619,279; and 4,821,750).
4 . A f lavorant undergoes a chemical reaction with
another compound to form a new _ulld that will
regenerate the original flavorant upon thermal
-sltion (see U.S. Patent 3,288,146).
Although there is substantial prior art, virtually
every implementation of this art pQss~oesec limitations
which render its commercial application impractical.
These limitations are largely def ined by the f lavorant
delivery strategy employed and will, therefore, be so
organized here.
Mechanical or physical f lavorant containment
devices which are incorporated into the f ilter and
~LuLed prior to smoking are very complex and expensive
to produce. They introduce signif icant variation into
the performance of the smoking article because of
inconsistencies in the pattern of their breakage, and
they interfere with the normal function of the filter by
altering smoke flow through the filter. They also
increase the effort and complexity to the consumer who
uses the product.
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Ad60rbed flavorant6 which are incc,.~ulc.ted into the
filter and released by the heat or moi6ture content o~
the 6moke are not efficiently delivered until enough of
the 6moking article has been crn ' to allow adequate
moi6ture and heat to reach the f ilter . A6 a
con6equence, the flavorant i6 not available to augment
smoke taste during the first few puff6, when it i6
generally acknowledged a6 being mo6t needed. In
addition, ab60rbant6 mu6t be cu6tomized to achieve the
desired release characteristics for each f lavorant and,
therefore, are not useful for delivering naturally
occurring f lavoring materials which consist of large
numbers of independent chemical entities.
Absorbed flavorants which are dissolved in polymer
matrice6 and relea6ed by the pla6ticizing action of
moisture or heat in the 6moke are 6ubject to the 6ame
limitation6 a6 ad60rbed flavorant6. In addition,
ab60rbed flavorant6 are 6ubject to time ~ r-~n~l~nt 1066e6
in delivery efficiency becau6e of diffusion of the
flavorant into the bulk of the fiber polymer. This
limitation is especially evident when a conventional
c~ 1ose acetate filter is used as the flavorant
absorber .
Derivatized flavorants are almo6t always
inappropriate for u6e in filter flavorant delivery
sy6tem6 because relatively high temperatures are
required for their release. Derivatized flavorants are,
therefore, typically applied to the tobacco portion of
the 6moking product, where the liberated flavorant .
produced during combustion is subject to chemical
alteration and loss during the static burn period of the
smoking article. The develûpment of derivatized
flavorants is highly specific for each flavorant and,
therefore, excludes naturally occurring~ flavoring
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materials which are ~-sefl of a large number of
- ; nfl--r-~nflPnt chemical entities .
Although f lavorants are the most commonly used
tobacco modifying agents, selective removal additives
5 can also serve as tobacco modifying agents. In contrast
to flavorants, selective removal additives modify
tobacco smoke by removing, rather than adding, certain
c or classes of: .ul,ds. SelectiVe removal
additives are applied to the filter and, therefore, like
f lavorants, can be absorbed by the f ilter f ibers and
lose their effectiveness. Here, too, significant
vv~ -nts in the performance of selective removal
additives could be achieved by OV~I~ in~ the
limitations imposed by the substrate to which the
additives are applied.
Such fibers capable of transporting hydrophilic or
hydrophobic fluids will be referred to herein as
"spontaneously transportable fibers" or, alternatively,
"spontaneously wettable fibers". We have unexpectedly
discovered that use of fibers of sufficiently complex
geometry, especially spontAn~ollcly transportable fibers,
in combination with tobacco modifying agents, such as
flavorants, results in improved delivery of such agents.
We have also unexpectedly discovered that use of these
fibers in combination with selective removal additives
results in i ov~:d selective removal of unwanted
materials such as phenol.
" ,C -ry of the Invention
The present invention is directed to a combination
comprising at least one fiber of sufficient geometry and
at least one tobacco modifying agent.
The fiber useful in the present invention has at
least one continuous groove oriented 2xia~ ly along the
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fiber wherein said fiber has a cross--section having a
shape factor X that satisfies the following equation:
X 4r + (1r--2 ) D
wherein
P is the perimeter of the f iber and r i8 the
radius of the circumscribed circle circumscribing
the f iber cross--section and D is the minor axis
dimension across the fiber cros6--6ection.
In a preferred Pmho~ nt, the fiber u6eful in the
present invention i6 capable of spontaneously
transporting water on the surf ace thereof and ha6 at
lea6t one continuous groove oriented axially along the
fiber, and said fiber satisfies the following equation
- (l--X cos a) < ~
wherein
~a i6 the advancing contact angle of water
mea6ured on a flat film made from the same material
as the fiber and having the same surface treatment,
if any,
X is a shape f actor of the f iber cross--section
that satisfies the following equation
X = 4r + (n--2)D
wherein
Pw is the wetted perimeter of the ~iber and
r is the radius of the circumscribed circle
circumscribing the f iber cross--section and D i6
the minor axis dimension across the f iber
cro66--6ection .
In another preferred ~ --nt, the fiber useful
in the present invention is capable of spontaneously
transporting n--decane on the surf ace thereof and has at
least one continuous groove oriented axially along the
fiber, and said fiber satisfies the following equation
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(1-X cos ~a) < ~
wherein
~a is the advancing contact angle of n--decane
measured on a flat film made from the same material
as the f iber and having the same 6urf ace treatment,
if any,
X is a shape f actor of the f iber cross--section
that satisfies the following equation
w
X ~ 4r + (7r--2)D
wherein
Pw is the wetted perimeter of the f iber and
r is the radius of the circumscribed circle
circumscribing the f iber cross--6ection and D is
the minor axis dimension across the fiber
cross--section .
For all of the f ibers useful in the present
invention, it is preferred that X is greater than 1.2,
more preferably greater than about 2.5, most preferably
greater than about 4. Also, it is preferred that 2D is
greater than 1, more preferred is where 2--D is between
1. 5 and 5 .
For the fibers that spontaneously transport water,
3 0 it is pref erred that the f iber of the invention
satisf ies the f ormula:
12 10 ~ (1--X cos ~aj < --0 3~
wherein YLA is the surface tension of water in air
in dynes~cm, p is the fiber density in grams~cc,
and dpf is the denier (kg~m) of the single fiber.
The combination of the invention preferably
comprises a plurality of the f ibers of the invention and
at least one tobacco modifying agent wherein the
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combination is in the form of a tobacco smoke filter in
ubstantially cylindrical form.
~rief Descri~tion of thé Drawinc~s
Figure 1 -- graph of percent delivery efficiency
versus milligrams (mg) of triacetin per filter for a
cigarette filter of the invention and for a conventional
cigarette filter. The o symbols represent filters of
the invention and the symbols represent filters made
from fibers of round cross--section.
Figure 2A -- illustration of the behavior of a drop
of a fluid which has just contacted a fiber that is
spontaneously transportable at time = O. The arrows
1 ~hP] 1 ed "LFA" indicate the location of the
liquid--fiber--air interface.
Figure 2B -- illustration of the behavior of a drop
of a fluid on a fiber that is spontaneously
transportable at time = t1 (tl >O). The arrows labelled
"LFA" indicate the location of the liquid--f iber--air
2 O interf 2ce .
Figure 2C -- illustration of the behavior of a drop
of a fluid on a fiber that is spontaneously
transportable at time = t2 tt2 >tl). The arrows
labelled "LFA" indicate the location of the
liquid--fiber--air interface.
Figure 3 -- schematic representation of an orif ice
of a spinneret useful for producing a spontaneously
transportable f iber .
Figure 4 -- schematic representation of an orif ice
of a spinneret useful for producing a spontaneously
transportable f iber .
Figure 5 -- schematic representation of an orif ice
of a spinneret useful for producing a spontaneously
transportable f iber.
,
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g _ ,
Figure 6 -- schematic L~:~uLesel~ation of an orifice
of a spinneret useful for producing a spontaneously
transportable f iber .
Figure 6B -- schematic representation of an orif ice
of a spinneret useful for producing a spontaneously
transportable f iber .
Figure 7 -- schematic representation of an orif ice
of a spinneret having 2 repeating units, joined end to
end, of the orifice as shown in Figure 3.
Figure 8 -- schematic representation of an orifice
of a spinneret having 4 repeating units, joined end to
end, of the orif ice as shown in Figure 3 .
Figure 9 -- photomicrograph of a poly (ethylene
terephthalate) f iber cross--section made using a
spinneret having an orif ice as illustrated in Figure 3
(specific dimensions of spinneret orifice described in
Example 1 ) .
Figure 10 -- photomi~;L Ul ~L ~h of a polypropylene
fiber cross--section made using a spinneret having an
orifice as illustrated in Figure 3 (specific dimensions
of spinneret orif ice described in Example 2 ) .
Figure 11 -- photomicrograph of a nylon 66 fiber
cross--section made using a spinneret having an orif ice
as illustrated in Figure 3 (specific dimensions of
spinneret orifice described in Example 2).
Figure 12 -- 6chematic representation of a
poly(ethylene terephthalate) fiber cross--section made
using a spinneret having an orifice as illustrated in
0 Figure 4 (specific dimensions of spinneret orifice
described in Example 8).
Figure 13 -- photûmicrograph of a poly(ethylene
terephthalate) fiber cross--section made using a
spinneret having an orifice as illustrated in Figure 5
(specific dimensions of spinneret orifice descrilbed in
Example 9 ) .
_ _ _
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Figure 14 -- photomicrograph of a poly(ethylene
terephthalate) fiber cross--section made using a
spinneret having an orifice as illustrated in Figure 7
(specific ~ of spinneret orifice described in
Example lO).
Figure 15 -- photomicrograph of a poly (ethylene
terephthalate~ f iber cross--section made using a
spinneret having an orif ice as illustrated in Figure 8
(specific dimensions of spinneret orifice described in
Example 11).
Figure 16 -- schematic representation of a f iber
cross--section made using a spinneret having an orif ice
as illustrated in Figure 3 (Example 1). Exemplified is
a typical means of determining the shape f actor X .
Figure 17 -- photomiuLuyL-ph of a poly(ethylene
terephthalate~ fiber cross--section made using a
spinneret having an orif ice as illustrated in Figure 6
(specific_dimensions of spinneret oririce described in
Example 12 ) .
Figure 17B -- schematic representation of a
poly(ethylene terephthalate) fiber cross--section made
using a spinneret having an orif ice as illustrated in
Figure 6B (specific dimensions of spinneret orifice
described in Example 13).
Figures 18 and 19 -- graphs showing the performance
of the invention for maintaining a constant delivery
efficiency for glycerol triacetate over extended pèriods
of 6torage.
.v
Detailed Descri~tion of the Invention
The fibers useful in the present invention have a
complex cross--section ,_ LLY that results in a surface
area that allows far more efficient delivery of tobacco
modifying agent to the user. These fiberS also allow
for more efficient selective removal when selective
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removal additives are applied to the fiber6 of the
present invention. The fibers are preferably
spontaneously transportable. For hydrophilic tobacco
modifying agents, the fibers are preferably the
preferred fibers that are capable of spontaneously
tr~nsporting water on the surfaces thereof. Similarly,
for hydrophobic tobacco modifying agents, the fibers are
preferably the preferred fibers that are capable of
spontaneously transporting n--decane on the surfaces
thereof.
It iB not desired to be bound by any particular
theory or ---hAnicm; however, it is believed that a
spon~n~o11c1y wettable fiber, when contacted with an
appropriate fluid tobacco modifying agent,~ transports
said agent on the fiber surface thereby substantially or
completely coating the fiber with the agent.- Also, it
is believed that if a spontaneously wettable fiber is
dipped or immersed in an appropriate f luid tobacco
modifying agent and then removed from the fluid, said
fiber retains a sufficient amount of said fluid which
also results in a fiber substantially or completely
coated with said agent. As used in this context, "an
appropriate fluid tobacco modifying agent" is one which
is capable of being spontaneously transported by the
fiber in question. The coated fibers are optionally
allowed to dry or substantially dry prior to use.
The three important variables fundamental to the
liguid transport behavior are (a) surface tension of the
liguid, (b) wettability or the contact angle of the
solid with the liquid, and (c) the geometry of the solid
surface. Typically, the wettability of a solid surface
by a liguid can be characterized by the contact angle
that the liquid surface (gas--liquid interface) makes
with the solid surface (gas--solid surface). Typically,
3~ a drop of liquid placed on a solid surface makes a
_ _ _ _ _, . _ . . ... .. _ . . .
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contact angle, 0, with the solid surface. If this
contact angle is less than 9O, then the solid is
on~ red to be wet by the liquid. However, if the
contact angle is greater than 90, 6uch as_with water on
Teflon (trademark) surface, the solid is not wet by the
llquid. Thus, it is desired to have a minimum contact
angie for ~nhAnr-~d wetting, but definitely, it must be
less than 90. However, the contact angle also depends
on surface inh~ ,cneities (chemical and physical, such
as r~ rhn~s), contamination, chemical~physical
Lre~l L of the 601id surface, as well as the nature of
the liquid surface and its contamination. Surface ~ree
energy of the solid also influences the wetting
behavior. The lower the surface energy of the solid,
15 the more difficult it is to wet the solid by liquids
having high surface tension. Thus, for example, Teflon,
which has low surface energy does not wet with water.
(Contact angle for Teflon--water system is 112 . )
However, it is possible to treat the surface of Teflon
with a monomolecular film ~of protein, which
signif icantly ~nhAnr~c the wetting behavior .~ Thus, it
is possible to modify the surface energy of fiber
- surfaces by al?propriate lubricants~finishes to enhance
liquid transport. The contact angle of polyethylene
terephthalate (PET), nylon 66, and polypropylene with
water is 80, 71, and 108, respectively. Thus,
nylon 66 is more wettable with water than PET. However,
for polypropylene, the contact angle is >90~, and thus
is nonwettable with water.
The second plO~er ~y of fl~nrl;~r Lal importance to
the rh~n~ - of liquid transport is surface tension of
the liquid.
The third property of fundamental importance to the
rh~nl -n~ of liguid transport is the geometry of the
solid surface. Although it is known that grooves
.
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enhance f luid transport in general, it has been
discovered that particular ~f tL les and arrangements
of deep and narrow grooves on f ibers and treatments
thereof can allow for the 6pontaneous surface transport
of fluids in single fibers. Thus, preferred fibers for
use herein are those with a combination of properties
wherein an individual fiber is capable of spontaneously
transporting water or n~ecane on its surf ace .
The particular geometry of the deep and narrow
lo grooves can be important. For example, in grooves which
have the f eature that the width of the groove at any
depth is equal to or less than the width of the groove
at the mouth of the groove, "bridging" of=the liquid
~cross the restriction is possible and thereby the
effective wetted perimeter (Pw) is reduced. Of course,
the f luid used to wet the f iber to determine the wetted
perimeter is, accordingly, water in the case of f ibers
which spontaneously transport water, and n-decane in the
case of fibers which spontaneously transport n--decane.
In any case, it is preferred that Pw is substantially
equal to the geometric perimeter.
The number of continuous grooves present in the
fiber useful in the present invention is not critical as
long as the required ge~ LLY is present. Typically
there are at least 2 grooves present, and preferably
less than 10.
"Spontaneously transportable" and derivative terms
thereof refer to the behavior of a fluid in general and
in particular a drop of f luid, such as water or
n--decane, when it is brought into contact with a single
fiber such that the drop spreads along the fiber. Such
behavior is contrasted with the normal behavior of the
drop which forms a static ellipsoidal shape with a
unique contact angle at the intersection of the liquid
~nd the solid fiber. It is obvious that the formation
_ . . . . _ . _ . .
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of the ellipsoidal drop takes a very 6hort time but
remains 6tationary thereafter. Figures 2A, 2B and 2C
illu6trate spontaneou6 f luid tran6port on a f iber
6urface. The key factor i6 the ~ L of the location
of the air, liquid, solid interface with time. If such
interface moves just after contact of the liquid with
the fiber, then the fiber i8 spontaneously
transportable; if such interf ace is stationary, the
fiber is not spont;~nDol~cIy transportable. The
6pontaneously transportable phDn~ e~on is easily visible
to the naked eye for large filaments (>20 denier (kg/m)
per ~ilament (dpf) ) but a microscope may be nDcncsAry to
view the fiber6 if they are less than 20 dpf. Colored
fluids are more ea6ily seen but the spontaneously
transportable rhPn~ --n is not rl~rDnrlDnt on the color.
It is possible to have sections of the circumference of
the fiber on which the fluid moves faster than other
SQctiOns. In such case the air, liquid, solid interface
actually extends over a length of the fiber. Thus, such
fibers are also spontaneously LLd~la~ Lable in that the
air, liquid, solid interface is moving as opposed to
stationary .
Spontaneous transportability is basically a surface
p~D- -nnn; that is the movement of the f luid occurs on
the surface of the fiber. However, it is possible and
may in some cases be desirable to have the spontaneously
tran6portable rhD- occur in conjunction with
absorption of the f luid into the f iber . The behavior
visible to the naked eye will depend on the relative .,
rate of absorption v6. 6pontaneous transportability.
For example, if the relatiYe rate of absorption is large
6uch that most of the f luid i6 absorbed into the f iber,
the liquid drop will fl; ~rpe~r with very little - .v~ - L
of the air, liquid, solid interface along the fiber
6urface wherea6 if the rate of absorption is small
.. . _ _ _ .. . . _ _ _ _ _ _ _ _ _ _ _ _
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conpared to the rate of spontaneous transportability the
observed behavior will be that of wlc.kins or transport,
as exemplified in Figures 2A through 2C. In Figure 2A,
a drop of aqueous fluid is just placed on the fiber
(time = 0). In Figure 2B, a time interval has elapsed
(time 5 tl) and the fluid starts to be 6pontaneously
transported. In Figure 2C, a second time interval has
passed (time = t2) and the fluid has been spontaneously
tran6ported along the fiber surface further than at
time = tl.
A preferred fiber useful in the present invention
is capable of spontaneously transporting water on the
surface thereof. Distilled water can be employed to
test the spontaneous transportability phenomeno~;
however, it is of ten de6irable to incorporate a minor
amount of a colorant into the water to better visualize
the 6pontaneous transport of the water, so long as the
water with colorant behaves substantially the same as
pure water under test conditions. We have found aqueous
Syltint Poly Red (trademark) from M; 11 ;k~n Chemicals to
be a useful solution to test the spontaneous
transportability ~h~n, -nnn. The Syltint Poly Red
solution can be used undiluted or diluted significantly,
e.g., up to about 50x with water. In addition to being
capable of transporting water, such a fiber useful in
the present invention is also capable of spontaneously
transporting a multitude of other hydrophilic fluids
such as aqueous f luids . Aqueous f luids are those f luids
comprising about 50% or more water by weight, preferred
'~ 30 is about 75~ or more water by weight, most preferred is
about 90% or more water by weight. In addition to being
able to transport aqueous fluids, such a fiber useful in
the present invention is also capable of transporting an
alcoholic fluid on its surface. Alcoholic fluids are
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~ 209~176 -~16 -
tbose fluids comprising greater than about 50% by weight
of an alcoholic cu_~vu.,d of the f ormula
R--O~ ~
wherein R is an aliphatic or aroDatic group containing
up to 12 carbon atoms. It i6 preferred that R is an
alkyl group of l to 6 carbon atoms, more preferred is l
to 4 carbon atoms. Examples of alcohols include
methanol, ethanol, n--propanol and iso--propanol.
Preferred alcoholic fluids comprise about 70% or more by
weight of a suitable alcohol. Of course, it is also
preferred that such a fiber is capable of spontaneously
transporting hydrophilic tobacco modifylng agents.
Another class of preferred ~ibers useful in the
present invention is capable of spontaneously
transporting n--decane on the surface thereof. As~in the
case of water as described hereinbefore, the n--decane
can be colorized for better visualization. In addition
to being capable of spontaneously transporting n--decane,
such a f iber is also typically capable of spontaneously
transporting other hydrophobic fluids such as cyclo--
hexane, xylene or ~--pinene. Of course, it is also
preferred that such a fiber is capable of spontaneously
transporting hydrophobic tobacco modifying agents.
The fibers useful in the invention can be comprised
of any material known in the art capable of having a
cross--section of the desired y~ y. Preferred
materials for use in the present invention are
polyesters .
The preferred polyester materials useful in the
present invention are polyesters or copolyesters that
are well known in the art and can be prepared using
standard techniques, such as, by polymerizing
dicarboxylic acids or esters thereof and glycols. The
dicarboxylic acid compounds used in the production of
polyesters and copolyesters are well known to those
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-- 17 -
skilled in the art and illustratively include
terephthalic acid, isophthalic acid, p,p'--diphenyl--
dicarboxylic acid, p,p'--dicarboxydiphenyl ethane,
p, p ~--d i carboxyd ipheny l hexane, p, p ~--d icarboxyd ipheny l
ether, p,p'--dicaLLc,~y~llenoxy ethane, and the li~e, and
the dialkylesters thereof that contain from 1 to about
5 carbon atoms in the alkyl groups thereof.
Suitable aliphatic glycols for the production of
polyesters and copolyesters are the acyclic and
alicyclic aliphatic glycols having from 2 to 10 carbon
atoms, especially those represented by the general
formula HOICH2)pOH, wherein p is an integer having a
value of from 2 to about 10, such as ethylene glycol,
trimethylene glycol, tetramethylene glycol, and
pentamethylene glycol, decamethylene glycol, and the
l ike .
Other known suitable aliphatic glycols include
~1,4--cycloh~Y~n~;r~thanol, 3--ethyl--1,5--pentanediol,
1, 4--xylylene, glycol, 2, 2, 4, 4--tetramethyl--1, 3--cyclo--
butanediol, and the like. One can also have present a
hydroxylcarboxyl c u.ld such as 4,--~,ydLuxybenzoic
acid, 4--hydroxyethoxybenzoic acid, or any of the other
hydroxylcarboxyl ~ ds known as useful to those
skilled in the art. ~
It is also known that mixtures of the above
dicarboxylic acid compounds or mixtures of the aliphatic
glycols can be used and that a minor amount of the
dicarboxylic acid component, generally up to about
10 mole percent, can be replaced by other acids or
modifiers such as adipic acid, sebacic acid, or the
esters thereof, or with modifiers that impart; LUV~d
dyeability to the polymers.
The most preferred polyester for use in preparing
the fiber useful in the invention is poly(ethylene
terephthalate) (PET).
_ _ _ _ _ . . . .. . _ .. _ _ _ _
WO 92/05713 PCr/US91/07109
20g21~6
~ -- 18 --
Other materials that can be used to make the base
fibers include polyamides such as a nylon, e.g.,
nylon 66 or nylon 6; polypropylene; polyethylene; and
cDll--lose esters such as celllllo~e triacetate or
cellulose diacetate.
A single f iber useful in the present invention
preferably has a denier (kg~m) of between about 1 and
about 1, 0 0 0, more pref erred is between about 5 and about
70 .
The fibers useful in the invention preferably have
a surface treatment applied thereto. Such surface
treatment may or may not be critical to obtain the
desired spontaneous transportability IJLU~eL~y. The
nature and criticality of such surface treatment for any
given fiber can be determined by a skilled artisan
through routine experimentation using techniques known
in the art and~or disclosed herein . A pref erred surf ace
treatment, when a hydrophilic tobacco modifying agent is
contemplated, is a coating of a hydrophilic lubricant on
the surface of the fiber. A preferred surface
treatment, when a hydrophobic tobacco modifying agent is
contemplated, is a coating of a hydrophobic lubricant on
the surface of the fiber. Such coatings are typically
uniformly applied at about a level of at least O . 05
weight percent, with about 0.1 to about 2 weight percent
being preferred, based on the weight of the fiber.
Preferred hydrophilic lubricants include a potassium
lauryl phosphate based lubricant comprising about 70
weight percent poly(ethylene glycol) 600 mono~aurate. A
preferred hydrophobic lubricant is mineral oii. Another
surface treatment is to subject the fibers to oxygen
plasma treatment, as taught in, for example, Plastics
Fini~hin~t and Decoration, Chapter 4, Ed. Don Satas, Van
Nostrand Reinho ld Company ( 19 8 6 ) .
.
,
WO 9~/05713 PCr/US91/07109
2~217~
-- 19 --'
Figures 3 through 8 illustrate spinneret orifices
which will prepare fibers of a geometry suitable for use
in the present invention.
In Figure 3, W is between 0 . 064 mi 11; ters (mm)
and 0 .12 mm. X2 is 4W +lwi X4 is 2W + 0 . 5W; X6 is
6W +2ww; X8 is 6W +25ww; X10 is 7W +25W; X12 i5 9W +15Ww;
X is lOW +5W; X is llW +5W; X is 6W +5W; t1 is
30 _ 30; t~4 is 45 + 45; 6 is 30 _ 30; and t~8 is
450 + 45O
In Figure 4, W is between 0. 064 mm and 0 .12 mm;
X20 is 17W +25Ww; X22 is 3W + W; X24 is 4W _ 2W; X26 is
60W _4W; X28 is 17W _2W; X30 is 2W + 0.5W; X32 is
35 72W 15W; and ~10 is 45 _ 15- In addition, each
40 Leg B can vary in length from 0 to 26; and each
45 Leg A can vary in length from 0 to
rX26
tan t90-t~lo) ~ 2 X2~1 =
In Figure 5, W is between 0. 064 mm and 0 .12 mm;
X34 is 2W + 0.5W; X36 is 58W 120W; X38 is 24W +26WW;
~12 is 20O +100; ~14 is 1 12; and n =
number of legs per 180 = 2 to 6.
In Figure 6, W is between 0.064 mm and 0.12 mm;
X42 is 6W +2Ww; X44 is llW + 5W; X46 is llW + 5W; X48
is 24W + lOW; X50 is 38W + 13W; X52 is 3W _3W; X54 is
80 6W +2W; X56 is llW + 5W; X58 is 7W + 5W; X60 is
WO 92/05713 PCr/US91/07109
20~21~6
-- 20 --
17W + 7W; X62 is 28W + llW; X64 is 24W + lOW; X66 is
17W + 7W; X 8 is 2W + 0.5W; Q16 is 45 --15; ~18
is 45 + 15; and 620 is i50 + 15.
In Figure 6B W is between 0 . 064 mm and 0.12 mm,
X72 is 8W _2W' X74 is 8W _2W' X76 is 12W + 4W, X78 is
8W + 4W, X80 is 24W +~12W, X82 is 18W + 6W, X84 is
8W_2W X86 is 16W + 6W, X88 is 24W + 12W, X90 is
18W + 6W, X92 is 2W + 0.5W, 22 is 135 + 30 ~ ~24 is
90 + 3050, ~26 is 45 + 15, ~28 is 45 + 15~, ~30 is
45 + 15, ~32 is 45 + 15, ~34 is 45 + 15, ~36 is
45o + 15, and ~38 is 45 + 15-
In Figure 7, the depicted spinneret orif ice
contains two repeat units of the spinneret orif ice
depicted in Figure 3, therefore, the same dimensions for
Figure 3 apply to Figure 7. Li3cewise, in Figure 8, the
depicted spinneret orifice contains four repeat units of
the spinneret orif ice depicted in Figure 3, theref ore,
the same dimension~ for Figure 3 applies to Figure 8.
Figure 16 illustrates the method for determining
the shape factor, X, of the fiber cross--section. In
Figure 16, r = 37.5 mm, Pw = 355.1 mm, D = 49.6 mm;
thus, for the fiber cross--section of Figure 16:
X = 355.1 = 1.72
4 x 37.5 + (7r -- 2) 49.6 "
The tobacco modifying agent useful in the present
invention can be any such agent used in tobacco products
and~or tobacco substitute products where delivery of
such agent to the user is desirable. Such agents
typically modify the taste and~or aroma of smoking
..
WO9~/05713 PCl`~US9~J~7~09
~921 7~
-- 21 --
product6. Thus, the tobacco modifying agent can be a
flavorant or other aromatic material including both
naturally occurring and synthetic materials regardless
of their hydrophobic or hydrophilic nature. Examples of
such tobacco modifying agents include flavorants,
6ynergistic flavor Pnh~nr~rs, physiological coolants and
other mouth or throat stimulants, with f lavorants being
pref erred .
Examples of f lavorants include tobacco note
flavorants comprising naturally occurring materials such
as aqueous (hydrophilic) tobacco extracts (as discloced
in U. S . Patent 3, 316, 919 incorporated herein by
reference in its entirety) and aromatics (as disclose~:l
in U. S . Patent 3, 424 ,171 incorporated herein by
reference in its entirety), and synthetic materials
which augment the minty, camphoraceous, spicy, peppery,
fruity, flowery, woody, green, or other tobacco flavor
and aroma notes. Other flavorants contemplated for use
in the invention include naturally occurring or
synthetic flavorants which introduce flavor notes that
are not normally indigenous to tobacco such as the
following which have been demonstrated to be useful on
filters by U.S. Patent 3,144,024 (incorporated herein by
reference in its entirety), wine, rum, coumarin, honey,
vanilla, juniper, molasses, maple syrup, chocolate,
menthol, and sugars. In addition, vanillin, licorice,
anethole, anise, cocoa, cocoa and chocolate by products,
sugars, humectants, eugenol, clove oil, triacetin, and
other generally accepted cellulose acetate flavorant
3 0 f ilter additives .
Examples of synergistic flavor ~nh;~nr-~rs include
smoothers such as glutamates and nucleotides as
disclosed in U.S. Patent 3,397,700 (incorporated
herein by reference in its entirety) and 2
cyclohexylcyclohexanone as disclosed in U. 5 . Patent~
WO 92/0~713 PCI/US91J07109
, .
~217~
-- 2 2 -- -
.. ; .
3,342,186 (incorporated herein by reference in its
entirety) .
r 1P~ of naturally occurring physiological
coolants include mint oils, menthol, camphor and
5 camphoraceous ~
- Examples of synthetic physiological coolants
include synthetic menthol and menthol derivatives (the
~:atter exemplif ied by menthol monoester disclo6ed in
U.S. Patent 3,111,127 (incorporated herein by reference
in its entirety), menthol acetals di6closed in U. S .
Patent 3,126,012 (incoL~v~i~ted herein by reference in
its entirety), menthol ethers dlsclosed in U. S. Patent
3,128,772 (incorporated herein by reference in its
entirety), menthol esters disclosed in U. S . Patent
-15 3,136,319 (incorporated herein by reference in its
entirety), synthetic camphor and camphvraceous compounds
such as cycloh~ Pnnn~c and cyclnh~Y In~nPc disclosed in
U.S. Patent 3,380,456 (incorporated herein by reference
in its entirety), and synthetic coolants as disclosed in
U.K. Patents 1,351,761 and 1,351,762 and U.S. Patents
4,296,255 and 4,230,688.
Examples of other mouth or throat stimulating
include either natural or synthetic compounds
such as nicotine, and its dérivatives, including, for
example, nicotine complexes and salts disclosed in U. S.
Patent 3,109,436 (incvl~v,~ted herein by reference in
its entirety).
A feature of the invention is the spontaneously
wettable character of the pref erred f ibers used f or the
. 30 tobacco modifying agent delivery substrate and~or the
selective removal additive substrate. Although not
- desired to be bound by any particular theory or
r~-h~n;~:~, it is believed that the ability of
spontaneously wettable fibers to transport and spread
fluids on fibers having high surface areas which are not
.
_ _ _ _ _ _ _ _ _ _ _ _ _ .
WO 9t/05713 PCIIU59t/07109
2~9~17~
-- 23 --
n~ S~ rily penetrated by the modifying agent is
responsible for the high delivery efficiencies and high
peL~;en~dge of selective removal of unwanted 6ubstrates
achieved by the combination of the invention. The
invention is, therefore, not limited to a specific
polymer or fiber ~L~a, ~, 6uch as fiber finish, or to
~ particular form of final fiber assemblage. Tobacco
modifying agent delivery articles and~or selective
removal additive delivery articles might, therefore, be
made from fibers in any suitable form, including but not
limited to, webs, continuous tows, and cut staple.
Also, webs can be powder, calendar or binder f iber
bonded, and staple can be loose or as a sliver.
Although thei preferred implementation of the invention
is a filter--like article employed either alone or in a
multi--component conf iguration such as in a combination
with a conventional cellulose acetate f ilter plug in a
dual filter arrangement, the physical form of the
tobacco delivery article and~or selective removal
delivery article is not thus limited. In addition, the
invention is not limited in its uses to cigarettes and
is likewi6e applicable to all smoking products including
pipes, and even novel and as yet unconceived of aerosol
sources. Thus, the combination of the present invention
is preferably in the form of a tobacco smoke filter or
material useful for the preparation thereof. Cigarette
filters are especially preferred. Accordingly, the
present invention is also directed to a tobacco smoke
f ilter comprising the combination of the invention
wherein said filter is in substantially cylindrical form
- having a length of about 5 to about 40 millimeters (mm),
preferably about 10 to about 30 mm, and a diameter of
about 15 to about 30 mm, preferably about 22 to about 2
mm. In a preferred, dual filter arrangement, the
WO 92/0i713 PCr/US91/07109
` 20~21~6 24 -
portion of the dual filter comprising the combination of
the invention is pref erably about 6 to about 15 mm .
The combination of the invention is useful for the
e~ficient and uniform delivery of tobacco modifying
agents. The combination of the invention is also usefu
for efficient and uniform selective removal of unwanted
substances such as phenol or nicotine. The direct
economic value of the invention results from cost
savings achieved through reductions in the quantity of
expensive agents, ~cpec~lly flavorants and selective
removal additives, that are needed to achieve a desired
organoleptic Qffect. Other benefits of the invention
include increased shelf life, improved con6istency of
product taste which results from more constant delivery
of the tobacco modifying agent over time, and improved
efficiency of selective removal of unwanted substances.
To prepare the combination of the invention, the
tobacco modifying agent(s) and~or selective removal
additive of choice is applied, typically as a fluid, to
an assemblage of fibers contemplated herein, especially
spontaneously wettable f ibers . Such assemblage can be,
for example, a nonwoven web or continuous tow, which is
then preferably made into a rod--like or cylindrical
article using f ilter making technology that is well
known to one skilled in the art. After application of
the tobacco modifying agent (s) and~or selective removal
additive to the fibers, the combination is optionally
dried by conventional pLocedu~s, for example, air
drying or oven drying, especially to remove excess r
solvent, if present. The rod--like article can be
subdivided into segments of an appropriate length which
are attached to an aerosol source such as the tobacco
column of a conventional cigarette either alone or in
conjunction with a conventional filter element, e.g.,
cellulose acetate filter, on the mouth and so as to give
_ _ _ _ _ _ _
WO 92105713 PCIIUS91/07109
,
- 25 -2~g2~
the appearance of a conventional cigarette f ilter . The
resulting;, U~IG L in fiavorant delivery performance
achieved by the invention is exemplified in Figures 1,
17 and 18 for the implementations described in
Examples 14 and 15 hereof. The resulting improvement in
6elective delivery performance is described in
Example 16 hereof.
Figure 1 contrasts the delivery of the commonly
used smoking article flavorant triacetin (glycerol tri--
acetate) from identical fiber assemblages consisting of
spontaneously wettable and non--spontaneously wettable
(round) fibers of comparable filament denier. The
f igure clearly demonstrates the substantial f lavorant
delivery advantage achieved by the spontaneously
wettable f iber assemblage .
Figure 18 contrasts the delivery of the commonly
used smoking article $1avorant triacetin (glycerol
triacetate) from equal pressure drop fiber assemblages
consisting of spontaneously wettable and conventional
cellulose acetate fibers. This figure shows that the
flavorant delivery advantage achieved by the
spontaneously wettable $iber assemblage is even greater
when compared to the performance of conventional
cP11l~1Ose acetate fibers. FurthP -L~t Figure 19 shows
that the delivery efficiency of the spontaneously
wettable polyester fiber web filter segments for
glycerol triacetate is relatively constant over extended
periods of storage, whereas the delivery efficiency of
the conventional cellulose acetate f ilter decreases
significantly.
For certain tobacco modifying agents, such as
volatile flavorants, it may be desirable to apply such
agents in a solution of a nonvolatile sûlvent in which
the agent is highly soluble. An example of this
implementation is to prepare a solution of menthol in a
WO 92/05713 PCr/US9l/07tO9
~ .
2o92l~ 6
-- 26 --
sufficiently nonvolatile solvent such as triacetin,
polyethyrene glycol, or mineral oil. The flavorant,
applied as a solution to the fiber ~sP~nhlage, will
remain on the AcE~ lAge dissolved in the solvent but
will still be spread uniformly over the fibers in a way
that results in its high delivery efficiency.
The amount of tobacco modifying agent in the
combination of the invention (as well as A~leDmhl AgeS
made therefrom such as cigarette filters) will vary
dDrDn~lin~ on, among other things, the nature of the
particular fibers, the chemical nature and potency of
the particular tobacco modifying agent, and the desired
type of delivery of the agént. However, a typical
amount of tobacco modifying agent is about O . 001 to
about 100 percent, ba6ed on the weight of the f ibers.
If the tobacco modifying agent is present as a solid
free of solvent, a preferred amount of agent is about
0.1 to about 50%, based on the weight of the fibers. If
the tobacco modifying agent is present as a liquid, a
preferred amount of agent is about 0.1 to about 109~,
based on the weight of the f iber .
Regarding total delivery o~ tobacco modifying
agent, the combination of the invention in a single
component cigarette filter form preferably results in at
least a 10% i uv~ - t, more preferably at least a 30%
uv, ~, in delivery of such agent to the user as
compared to a control filter using fibers of round
cross--section .
The selective removal additives useful in the
present invention are specific rhD~nic~ c or
mixtures of o~n~c that are applied to f ilter fibers
to enhance the removal of certain ~ ,ul.ds or classes
of s _ -c from cigarette smoke. Selective removal
additives may be fluids or solids. If solids are used,
they are frequently applied to the filter medium as a
WO 92/0~713 PC~IUS91/011û9
2~92~76
,
solution in an appropriate solYent or as a suspension in
an ~JL V,~ iate f luid medium .
Examples of fluid selective removal additives which
t are useful for removal of phenols include polyols and
their esters such as diethyl citrate, glycerol
triacetate, triethylene glycol diacetate, poly(ethylene
glycol) 400 or 600, and triethylene glycol.
Examples of fluid selective removal additives which
are useful for removal of nicotine are glycerin and
distilled monoglycerides derived from edible fats and
glycerine, such as Myverol (trademark) and Myvatem
(trademark) sold by Eastman Chemical Company, a division
of Eastman Kodak Company, T~n~qpr~rt, TN.
Examples of solid selective removal additives that
can be applied as solutions or suspensions in the
appropriate fluid include salcomine, which is useful for
selectively removing nitrogen oxides, zinc oxide, which
is useful for selectively removing hydrogen cyanide,
polyethyl~nr~;~;ne, which is useful for selectively
removing aldehydes. Other generally useful additives
include activated carbon, ion exchange resins, zeolites,
waxes or starches.
The following examples are to illustrate the
invention but should not be interpreted as a limitation
2 5 thereon .
,TCXAMP,T .l;~.C
ExAMPLE 1 (Fiber Preparation)
Poly(ethylene terephthalate) (PET) polymer of 0.6
I.V. was used in this example. I.V. is the inherent
viscosity as measured at 25C at a polymer concentration
of O . 50 g~loO milliliters (mL) in a suitable solvent
such as a mixture of 60% phenol and 40% tetra-chloro-
3 5 ethane by weight . The polymer was dried to a moisture
. . , _ . _ _ _ _ _
WO 92/05713 PCI/US91/07109
; = ' ~.
~ ~ .
. .
~og21~6 - 28 -
level of <0 . 003 weight percent in a Patterson Conaf orm
dryer at 1206C for a period of 8 hours. The polymer was
exl_~uded at 283C through an Egan extruder 1.5--inch
(38.1 mm) diameter with a length to diameter ratio of
28:1. The fiber wa6 extruded through an eight orifice
spinneret wherein each orif ice is as shown in Figure 3
wherein W is 0. 084 mm X2 is 4W X4 is 2W X6 is 6W X8
is 6W X10 is 7W X12 i8 9W X14 is lOW X16 is llW X18
iB 6W ~2 i6 0, 04 is 45 66 is 30 and ~8 is 45.
The polymer tll~uuyll~u~ was about 7 pounds (lb)~hour
(3.18 kg~hour). The air quench system has a cross--flow
conf iguration . The quench air velocity at the top of
the screen was an average of 294 feet (ft)~minute (89.61
m/minute) . At a distance of about 7 inches ( 177 . 8 mm)
from the top of the screen the average velocity of the
guench air was about 285 ft/minute (86.87 m~minute) and
at a distance of about i4 inches (355. 60 mm) from the
top of the screen the average quench air velocity was
about 279 ft~minute (85. 04 m/minute) . At about 21
inches (533.40 mm) ~rom the top of the air screen the
average air velocity was about 340 ft/minute (103 . 63
m/minute). The rest of the screen was blocked.
Spinning lubricant was applied via ceramic kiss rolls.
The lubricant has a general composition as follows: it
is a potassium lauryl phosphate (PLP) based lubricant
having poly(ethylene glycol) 600 monolaurate (70% by
weight) and polyoxyethylene (5) potassium lauryl
phosphate (30% by weight). An emulsion of the above
lubricant with water (90%) was used as the spinning
lubricant. The lubricant level on the fiber samples was
about 1.5%. Fibers of 20 dpf (denier per filament in
kg/m) were wound at 3 000 meters per minute = (MPM) on a
Barmag SW4SL winder. A photomicrograph of a
cross--section of this fiber is shown in Figure 9 (150x
magnification). The single fiber was tested for
.. ,,,.,.. .. ,, .. ~._ _ .. ,.. .. ,.,, ... , , , _ ___
WO92/057t3 PCI/US91/07109
209217G
-- 29 --
spontaneous surf ace transportation of an aqueous
solution which was aqueous Syltint Poly Red (obtained
from Mi 11 ;k~n Chemicals) which is 80 weight % water and
r 20 weight ~ red colorant. The single fiber of 20 dpf
(kg~m per filament) spontaneously surface transported
the above aqueous solution. The following denier (kg~m)
per filament PET fiber6 were also made at different
speeds as shown in Table 1 below:
Tilhl e 1
Denier
(kg~m)
per Spin Speed
Fi l ~--nt rMP~l Winder
3, 000 Barmag
1,500 Leesona
l, 000 Leesona
120 500 Leesona
240 225 ~ Leesona
4 0 0 15 0 Leesona
All the single fibers of above PET fiber with the denier
(kg~m) per filament of 20, 40, 60, 120, 240, and 400
spontaneously surface transported the aqueous solution
of Syltint Poly Red liquid. The value of the "X"
parameter (as defined hereinbefore) for these fibers was
about 1.7. PET film of 0.02 inch (0.51 mm) thickness
was _ .~ssion molded from the same polymer as that
used f or making the above f iber . Contact angle of
distilled water on the above film was measured in air
with a contact angle goniometer. The contact angle was
71.7. Another sample of the same film as above was
sprayed with the same lubricant as used for making the
fiber in this example at about 1.59c level. The contact
angle of distilled water on the PET film sprayed with
3~ the lubricant was about 7 0 . Thu~, the factor
WO 92/05713 PCr/US91/07109
-- 30 -- -
(1--X cos 0) in this case i6 (1--1.7(cos 7)) =--0.69,
which i5 less than zero.
I;Y~ pT,F 2 (Fiber Preparation)
Polyhexamethylene ~l;rAm;fl~ (nylon 66) was obtained
from Du Pont [ Zytel (trademark) 42 ] . The polymer was
t:XL- uded at 279C. A spinneret as shown in Figure 3 was
used to form 46 denier (kg~n~) per filament fiber at 255
meter6~minute speed. The specif ic dimension6 of the
spinneret orifices were the same a6 described in
Example 1 except that ~2 wa6 30 instead of 0. The
g~ nch; n~ conditions were the same as those f or
obtaining PET fiber a6 in Example 1. A photomicrograph
of the fiber cro66--6ection i6 6hown in Figure 11 (lSOx
magnif ication) . The lubricant level on the f iber wa6
about 1. 8% by weight . The 6ame lubricant a6 u6ed in the
PET fiber wa6 u6ed (Example 1). Thi6 nylon 66 fiber
6pontaneou61y tran6ported the agueou6 Syltint Poly Red
601ution on the fiber surface. The value of the "X"
parameter for this fiber was about 1.9. Nylon 66 film
of 0. 02 inch (0. 51 mm) thickness wa6 compre66ion molded
from the 6ame polymer a6 that u6ed for making the fiber
of Example 2. Contact angle of di6tilled water on the
above f ilm was measured in air with a contact angle
goniometer. The contact angle was 64 . Another 6ample
of the 6ame f ilm a6 above wa6 sprayed with the 6ame
lubricant as used for making the fiber in this example
at about the 1. 8% level . The contact angle of distilled
water on the nylon 66 film sprayed with the lubricant
wa6 about 2. Thu6, the factor (1--X cos ~) in this case
i6 (1--l.9(c06 2)) = --0.9, which i6 le66 than 2ero.
WO 92/057t3 PCrJOS91/D7109
2~176
,,
-- 31 --
F~AMPLE 3 tFiber Preparation)
Polypropylene polymer was obtained from Shell
Company (Grade 5C14). It was extruded at 279C. A
spinneret as shown in Figure 3 was used to f orm
51 denier (kg~m) per filament fiber at 2,000 MPM speed.
The specific diDensions of the 6pinneret orifices were
the same as in Example 2 . The gl~pnr~h; n~ conditions were
the same as those f or obtaining PET f iber . A
photomi.:, vy~clph of the fiber cross--section is shown in
Figure 10 t375x magnification). The lubricant level on
the f iber was 2 . 6% . The same lubricant as used in PET
fiber was used (Example 1). The polypropylene fiber
spontaneously transported the aqueous Syltint Poly Red
solution on the fiber surface. This spontaneously
transportable phPr rm along the fiber surface was
also observed for a 10 denier (kg~m) per filament,
single polypropylene fiber. The value of the "X"
parameter f or this f iber was about 2 . 2 . Polypropylene
film of 0.02 inch (0.51 mm) thickness was: ~ssion
molded from the same polymer as that used for making the
above fiber of Example 3. Contact angle of aistilled
water on the above f ilm was measured in air with a
contact angle goniometer. The contact angle was about
110. Another sample of the same film as above was
sprayed with the same lubricant as used for making the
fiber in this example at about the 2 . 6% level. The
contact angle of distilled water on the polypropylene
film sprayed with the lubricant was 12. Thus, the
factor (1--X cos 0) in this case is --1.1, which is less
3 0 than zero .
F~AMPT.~ 4 (Fiber Preparation)
Cellulose acetate (Eastman Grade CA 398--30,
Class I) was blended with PEG 400 polymer and small
quantities of antioxidant and thermal stabilizer. The
WO92/05713 ~ PCI~US91/07109
r
2~2i7
-- 32 -
blend was melt exL- uded at 270C. A 6pinneret as shown
in Figure 3 was used to form 115 denier ~kg~m) per
fllament fiber at 540 meters~minute speed. The specific
in~C of the spinneret orifices were the same as in
Example 2. No forced quench air was used. The
lubricant level on the fiber was 1.6%. The same
lubricant as used in the PET fibers (Example 1) was
used. The celiulose acetate fiber spontaneously
transported the aqueous Syltint Poly Red solution on the
fiber surface. The yalue of the "X" parameter fQr this
f iber was about 1. 8 ~
E~AMPLE 5 (Comparative)
PET f iber of Example 1 was made without any
spinning lubricant at 20 denier (kg~m) per filament. A
single f iber did not spontaneously transport the aqueous
Syltint Poly Red solution along the fiber surface.
FXAMPL~ 6 (Comparative)
PET fiber of circular cross--section was made. The
denier (kg~m) per filament of the fiber was 20. It had
about 1. 5% of the lubricant used in Example 1. A single
f iber did not spontaneously transport the aqueous
Syltint Poly Red solution along the f iber surf ace .
.
~XAMPLE 7 (Fiber Preparation)
Poly(ethylene terephthalate) (PET) fiber of
Example 5 (without any spinning lubricant) was treated
with oxygen plasma for 30 seconds. Model "Plasmod"
3 0 oxygen plasma equipment was used . Exciter power is
provided by the RF generator operating at 13.56 MHz
frequency. The plasma treatment was conducted at a
constant level of 50~ watts power. The oxygen plasma
treated f iber spontaneously transported the aqueous
Syltint Poly Red solution along the fiber. This fiber
~ .
_
WO 92/05713 PCI/US91/07109
2~2176
-- 33 --
was tested again after washing five times and after 3
days and the spontaneously transportable behavior with
the above aqueous solution was still observed. In order
to cletermino the reduction in contact angle after the
plasma treatment, a PET f ilm of the same material as
that of the fiber was subjected to the oxygen plasma
treatment under the same conditions as those used for
the f iber sample . The average contact angle of the
oxygen plasma treated f ilm with distilled water in air
was observed to be 26 as measured by a contact angle
goniometer . The corroSpQn~l; n~ contact angle f or the
control PET film (not exposed to the oxygen plasma) was
70. The significant reduction in contact angle upon
subjecting the untreated PET fiber to the oxygen plasma
treatment renders it to be spontaneously surf ace
transportable for aqueous solutions.
~MPL~ 8 ~Fiber Preparation)
Poly (ethylene terephthalate) (PET) polymer of 0 . 6
IV was used in this example. It was extruded through a
spinneret having eight orif ices as shown in Figure 4
wherein W is 0. 084 mm, X20 is 17N, X22 is 3W, X2~ is 4W,
X26 is 60W, X28 is 17W, X30 is 2W, X32 i5 72W, ~lO is
45, Leg 8 is 30W, and Leg A i5 26W. The rest of the
prococcin~ conditions were the same as those described
in Example l. A lO0 denier (kg~m) per filament fiber
was spun at 600 MPM. A sketch of the cros6--section of
the f iber is shown in Figure 12 . The lubricant level on
the f iber was about 1% . The same lu~ricant as used in
Example l was used. The above fiber spontaneously
transported the aqueous Syltint Poly Red solution along
the fiber surface. The value of the "X" parameter for
this f iber was l . 5 .
WO 92/05713 PCI`/US91/07109
--
2092~ 34_ ~= -
l~n~MPT.T;~ 9 (Fiber Preparation)
Poly (ethylene terephthalate) polymer of 0 . 6 IV was
used in this example. It was extruded through a
spinneret having eight orif ice6 as shown in Figure 5
wherein W is 0.10 mm X34 is 2W X36 is 58W X38 is 24W
~12 is 20 ~14 is 28 and n is 6. The rest of the
extruding and spinning conditions were the same as those
described in Example 1. A photomicrograph of the f iber
cross--section is shown in Figure 13 (585x magnifi--
cation). A 20 denier (kg~m) per filament fiber was spun
at 3000 MPM. The lubricant level on the fiber was about
1.7%. The same lubricant as used in Example 1 was used.
The above f iber spontaneously transported the aqueous
Syltint Poly Red solution along the f iber surf ace . The
value of the "X parameter f or this f iber was about 2 . 4 .
F~AMPLr 10 (Fiber Preparation)
Poly (ethylene terephthalate) (PET) polymer of about
0. 6 IV was used in this example. The polymer was
extruded through a spinneret having four orifices as
shown in Figure 7 wherein the dimensions of the orifices
are repeats of the dimensions described in Example 2.
The rest of the processing conditions were the same as
those described in Example 1 unless otherwise stated. A
200 denier (kg~m) per filament fiber was spun at
600 MPM. The polymer Llllouyll~u~ was about 7 lbs~hr
(3 .18 kg~hr) . An optical photomicrograph of the f iber
is shown in Figure 14 (150x magnification). The
lubricant level on the fiber was 2.0%. The same
lubricant as used in Example 1 was used. The above
fiber spontaneously transported the aqueous Syltint Poly
Red solution along the fiber surface. The value of the
"X parameter f or this f iber was about 2 . 2 .
WO 92/05713 PCI`~US91~07109
.~
2~2176
-- 35 -
~XAMPT F 11 (Fiber Preparation)
Poly (ethylene terephthalate) (PET) polymer of O . 6
IV was used in this example. The polymer was extruded
through a spinneret having two orif ices as shown in
Figure 8 wherein the dimen6ions of the orif ices are
repeats of the dimensions described in Example 2. The
rest of the proces6ing conditions were the same as those
described in Example 1. A 364 denier (kg~m) per
filament fiber was spun at 600 MPM. The cross--section
of the fiber is shown in Figure 15 (150X magnification).
The lubricant level on the fiber was about 2.7%. The
same lubricant as used in Example 1 was used. The above
f iber spontaneously transported the aqueous Syltint Poly
Red solution along the fiber surface. The value of the
"X" parameter for this fiber was 2.1.
~AMPLF 12 ~Fiber Preparation)
Poly(ethylene terephthalate) (PET) polymer of 0.6
IV was used in this example. It was extruded through a
spinneret having eight orifices as shown in Figure 6
wherein W is 0.10 mm X42 is 6W, X44 is llW X46 is llW
X48 is 24N~ Xso is 38W, Xs2 is 3W, X54 is 6W, X56 is
llW, X58 is 7W, X60 is 17W, X62 is 28W, X64 is 24W, X66
is 17W, X68 is 2W, 16 is 45, G18 is 45, and ~20 is
45. The rest of the processing conditions were the
6ame as tho6e de6cribed in Example 1. A 100 denier
(kg~m) per filament fiber was spun at 600 MPM. The
cros6--6ection of the f iber is shown in Figure 17 . The
lubricant level on the f iber was about 1% . The 6ame
3 0 lubricant a6 u6ed in Example 1 was used . The above
- fiber spontaneously transported the aqueous Syltint Poly
Red solution along the fiber surface. The value of the
X parameter for this fiber was 1.3.
WO92/0~713 PCI/USgl/07109
2Q~21~
13 (Fiber Preparation)
PET polymer of 0. 6 I.V. is used in this example.
It is extruded through a spinneret having 8 orif ices as
shown in Figure 6B wherein W is 0.10 mm, X72 i8 8W, X74
i5 8W, X76 is 12W, X78 is 8W, X80 is 24W, X82 is 18W,
X84 is 8W, X86 is 16W, X88 is 24W, XgO is 18W, X92 is
2W, 22 is 135, 24 is 90, ~26 is 45, ~28 is 45, ~30
is 45, 632 is 45, 034 is 45, 36 is 45O and 638 is
45. A 20 denier (kgxm) per filament fiber is spun at
lo 3, ooo m~min. The rest of the prorc~c~:i n~ conditions are
the same as those used in Example 1. The lubricant
level on the f iber is about 1% . The cross--section of
the f iber is shown in Figure 17B . This f iber
spontaneously transports the aqueous Syltint Poly Red
solution along the fiber surface. The "X" value for
this f iber is about 2 .1.
LF 14 (Example of the Invention)
Spontaneously wettable polyester fibers were melt
spun from polyethylene terephthalate polymer according
to the methods described in Example 1. The value of the
X parameter (as defined hereinbefore) for these fibers
was about 1.8. A yarn of these fibers was then drafted
to 5 . 5 denier (kg~m) per f ilament, heat set at about
180C, crimped to about 7 or 8 crimps per inch (25.4
mm), and cut into 2--inch (50.8 mm) long staple fibers.
The resulting staple f ibexs were carded and bonded with
about 15 weight % Eastobond (trademark) FA--252 polyester
adhesive in powder form into a nonwoven web with a
density of about 19 grams per square yard (22.71
grams~square meter) . Round cross section f iber webs to
be used as controls were made by an identical process
except that the f ibers were melt spun through spinnerets
with round holes.
WO 92/0~713 PCl/US91/07tO9
2~921~
The resulting round and spontaneously wettable
polye6ter fiber webs were slit lengthwise into pieces
approximately 12 inches (304.80 mm) wide which were then
cut into 24--inch (609_ 60 mm) long sections. The
resulting 12--inch (304.80 mm) wide by 24--inch (609.60
mm) long web sections weighed approximately 4 grams
each. Glycerol triacetate, also referred to as
triacetin flavorant, either in its pure form or as a 10,
20, or 50 weight % solution in ethanol, was applied in
roughly equal quantities to both round and spontaneously
wettable fiber web sections using an aerosol sprayer.
The web sections were air dried overnight to remove the
residual ethanol.
The dried web sections were pulled lengthwise into
drinking straws which were about 23 mm in circumference
and each straw was cut into 21--mm long segments. The
21--mm long round fiber web filled straw segments
contained about 150 mg of web and had an average
pressure drop of about 28 mm of water when measured at a
flow rate of 17.5 cc~sec. of air. The 21--mm long
spontaneously wettable fiber web filled straw segments
also contained about 150 mg of web but had an average
pressure drop of about 55 mm of water when measured at a
f low rate of 17 . 5 cc~sec . of air . Each 21--mm segment
contained between 2 and 18 mgs of glycerol triacetate
depending upon the application rate.
The 21--mm long web filled straw segments were then
attached to 63--mm long blended tobacco columns that had
been cut of f a popular king--sized domestic cigarette
3 o brand, and the resulting cigarettes were smoked
according to CORESTA Standard Method No. 10 enti~led
"Machine Smoking of Cigarettes and Determination of
Crude and Dry Smoke c~n~pn~atel~ Experimental
cigarettes were smoked in groups such that one glasS
fiber filter pad was used to collect the smoke
WO 92/0~713 PCr/US91/0710g
~ .i
2~9217~
-- 38 -
con~Pn~:ate from five cigarettes. Each glas6 fiber
f iiter pad was then extracted with 15 ml o~ isopropanol
containing 0 . 4 mg~ml hPY~d~Pc~np as an internal standard .
The glycerol triacetate present in the isopropanol
extract of the cnn~lPn~ate from each glass fiber pad was
then quantitatively detPrm; nPd by capillary gas
chromatography .
The performance of the invention for delivering
glycerol triacetate is reported in Figure 1. The
reported delivery efficiency is defined as the
percentage of the f lavorant present on the f iber web
filled straw segment before smoking that was delivered
to the glass fiber filter pad by smoking the
experimental cigarettes. The term "4SW" represents
fibers capable of spontaneously transporting water on
the surfaces thereof.
; XAMP~,F lS (Example of the Invention)
Spontaneously wettable polyester fibers were melt
spun from polyethylene terephthalate polymer according
to the methods described in Example 1. The value of the
X parameter (as defined hereinbefore) for these fibers
was about 1. 7 . A yarn of these f ibers was then draf ted
to 10.3 denier (kg~m) per filament, heat set at about
180 degrees centigrade, crimped to about 7 or 8 crimps
per inch (2S.4 mm), lubricated with poly(ethylene) 600
monolaurate lubricant, and cut into 2 inch (50.8 mm)
long staple fibers. The spontaneously wettable staple
fibers were blended with about 20 weight % Kodel
(trademark) 410 amorphous polyester binder fiber, carded
and thermally bonded into a nu.l u vt:., web with a density
of about 35 grams per square yard (41.53 grams~square
meter). The resulting web was then slit into sections
9.4 inches (238.76 mm) wide and wound onto rolls about
1000 linear yards (914.40 meters) long.
-
WO 92/05713 PCr/US9l/07109
~ ~92176
,
-- 39 --
Rolls o~ spontaneously wettable polyester fiber web
were processed into filter rods in the following manner.
An Eastman Niniature filter tow processing unit was used
to unwind the web from the roll, to quantitatively apply
glycerol triacetate to the web at each of the two target
application rates, and to control the rate of delivery
of the web to the next step of the process. A Molins
PM--2 f ilter rod making machine was then used to f old the
web into rod shaped cylinders which were wrapped with
Ecusta 646 plugwrap. The resulting filter rods were cut
into 21 mm long segments which were 24.5 mm in
circumference, contained about 178 mg of nonwoven web,
and had an average ~L~S::~UL~ drop of about 27 mm of water
when measured at a f low rate of 17 . 5 cc~sec of air .
DPPPr~ n~ on the rate of application, each filter
segment contained either 2 . ~ mg or 5 . 6 mg of glycerol
triacetate which, when expressed a6 a percentage of the
total filter weight, COLLe~y~ ded to levels of 1.3 and
2 . 8 weight percent respectively .
As a comparison, flavored control filters were made
in the conventional manner from 3 . 3 denier (kg/m) per
filament, 39,000 total denier (kg~), Y cross section,
Estron (trademark) fiolution spun cellulose acetate
filter tow. The 21 mm long filter segments were 24.5 r~n
in circumference, contained 120 mg of filter tow, and
had an average ~L~S~UL~: drop of about 65 mm of water
when measured at a f low rate of 17 . 5 cc~sec of air .
Each filter segment contained 10. 3 mg of glycerol
triacetate which, when expressed as percentage of the
total filter weight, corresponded to a leYel of 7.0
weight percent.
~he spontaneously wettable polyester fiber web
filter segments were then placed in sealed glass jars
and stored for intervals consisting of 10, 18, 28, 39,
52, 66, and 82 days. At the end of each storage
_ . .. _ _ .. ... . . ..
WO 92/05713 PCr/US91/07109
2~g2~ 40 -
interval, the filters were attached to 63 mm long
blended tobacco columns that had been cut of f of a
popular King sized domestic cigarette brand and the
resulting cigarettes were smoked acccording to CORESTA
Standard Method No. 10 entitled "Machine Smoking of
Cigarettes and Determination of Crude and Dry Smoke
~nn~ ncate~l. The cellulose acetate control filters were
stored for intervals of 3, 7, 14, 21, 28, 42, 56, and 84
days prior to smoking.
Both eYperimental and control cigarettes were
smoked in groups such that one glass f iber f ilter pad
was used to collect the smoke con~l~n~te from 4
cigarettes. Each glass fiber filter pad was then
extracted with 15 ml of isopropanol containing 0 . 4 mg~ml
h~Y~qeC;~ne as an internal standard. The glycerol
triacetate present in the extract of the cnnrl~nc~te from
each glass f iber pad was then quantitatively determined
by capillary gas chromatography.
Figure 18 reports the perf ormance of the invention
for achieving consistantly higher delivery efficiencies
of glycerol triacetate than the control cellulose
acetate filters. The delivery efficiency reported in
Figure 18 is def ined as the percentage of the glycerol
triacetate present on the f ilter segment bef ore smoking
that was dèlivered to the glass f iber pad by smoking the
experimental and control cigarettes. Figure 2 shows
that the delivery efficiency of the spontaneously
wettable polyester fiber web filter segments for
glycerol triacetate was 2 to 3 times greater than the
delivery efficiency of the conventional cellulose
acetate filter segments initially and 3 to 4 times
greater by the end of the experiment. These higher
delivery efficiencies permit significant reductions in
the amount of flavorant that must be used to achieve a
desired delivery.
_ _ . . _ . . . _ . . . _ .
WO 92/0~713 PCr/US9~07109
~09217f~ ~-
-- 41 --
Figure l9 reports the perf ormance of the invention
for maintaining a constant deliYery efficiency of
glycerol triacetate over extended periods of storage.
The delivery efficiency change reported in Figure 3 is
defined as the percentage change in deliYery efficiency
relative to the delivery efficiency anticipated from a
freshly made filter. Figure 19 shows that the delivery
efficiencies of the two spontaneously wettable polyester
fiber web filter segments for glycerol triacetate are
virtually in~r~n~t of storage t~ime and, therefore,
show little change, whereas the conventional cellulose
~cetate filter segments loose almost half of their
already lower dellvery ef f iciency during the time
spanned by this experiment. - =
F~AMPLF 16 (Example of the Invention)
Spontaneously wettable polyester f ibers were melt
spun from polyethylene terephthalate polymer according
to the methods described in Example 1. The value of the
X parameter (as defined hereinbefore) for these fibers
was about 1.8. A yarn of these fibers was then drafted
to 5.5 denier (kg~m) per filament, heat set at about 180
degrees centigrade, crimped to about 7 or 8 crimps per
inch (25.4 mm), and cut into 2 inch (50.8 mm) long
staple fibers. The resulting staple fibers were carded
and bonded with about 15 weight % Eastobond FA--252
polyester adhesive powder into a nonwoven web with a
density of about 19 grams per square yard (22 . 71
grams~square meter) . Round cross section f iber webs to
be used as controls were made by an identical process
except that the f ibers were melt spun through spinnerets
with round holes.
The resulting round and spontaneously wettable
polyester fiber webs were slit lengthwise to widths of
35 15 and 12 inches (381.Oo and 304.80 mm), respectively.
- 42 -
The round webs were slit to a wider width in order to
better match the pressure drops of the resulting
filters. Selective removal additives consisting of
either glycerol triacetate or poly(ethylene glycol) 600
were applied to each web at a level of 7 weight percent
using an aerosol sprayer. Glycerol triacetate was
applied to the webs in pure form but, because of its
higher viscosity, poly(ethylene glycol) 600 was applied
as a 10% aqueous solution. The poly(ethylene glycol)
600 treated webs were dried in an oven at 60 degrees
centigrade for 1 hour after spraying to remove excess
water. All of the treated webs were allowed to air dry
overnight to remove residual volatiles.
The dried web sections were pulled lengthwise into
drinking straws which were about 23 mm in circumference
and each straw was cut into several 21 mm long segments.
Filters were made in this manner to achieve a target
pressure drop of about 70 mm of water when measured at a
flow rate of 17.5 cc/sec of air. Because of differences
in the relative abilities of the round and 4SW fiber
webs to generate pressure drop, filters made from these
two types of web contained different quantities of
coated substrate. To achieve the target pressure drop,
21 mm long filters required about 210 mg of coated round
fiber PET web and about 160 mg of coated 4SW fiber web.
As an additional comparison, straw filters were
also made from a 3.3 denier (kg/m) per filament, 39,000
total denier, Y cress section, Estron solution spun
cellulose acetate filter tow that had been treated with
either glycerol triacetate or poly(ethylene glycol) 600.
The resulting 21 mm long filter tips were 23 mm in
circumference, contained about 130 mg of treated
cellulose acetate filter tow, and had an average
pressure drop of about 75 mm of water when measured at a
flow rate of 17.5 cc/sec of air. Each filter segment
WO 92/05713 PCr~US91~07109
. .~
20~2~7~
-- 43 --
contained between 8 and 9 mg of either glycerol
triacetate or poly (ethylene glycol) 600 which,
L-~sced as percentage, ccLLe~ ds to an application
level of 7 . 0 weight percent.
The 21 mm long treated straw filters were attached
to 63 mm long blended tobacco columns that had been cut
off of a popular King sized domestic cigarette brand and
the resulting cigarettes were smoked acccording to
CORESTA Standard Nethod No. l0 entitled "Machine Smoking
of Cigarettes and Determination of Crude and Dry Smoke
~,n~PnRate". Experimental cigarettes of a given type
were smoked in groups such that one glass f iber f ilter
pad was used to collect the smoke cQn~lPncate from 5
cigarettes. The selective removal efficiency of the
filters was then detP~m;nP~l by measuring the amount of
phenol present in the glass fiber filter pads and the
freshly smoked cigarette f ilters .
In order to measure the phenol present, the glass
f iber f ilter pads and cigarette f ilters were both
6eparately extracted with diethyl ether and the
resulting extracts were concentrated, purif ied, and
quantitately measured using gas chromatography. The
percentage of selective phenol removal reported herein
is defined as l00 times the amount of phenol on the
cigarette filters divided by the sum of the amount of
phenol on the cigarette f ilters and the amount of phenol
on the glass fiber filter pad.
The perf ormance of the invention f or the selective
removal of phenol from cigarette smoke is reported in
Table l. In all cases, the application of selective
removal additives such as glycerol triacetate and poly
(ethylene glycol~ 600 to 4SW PET fiber web produced
filters with higher selective removal efficiencies for
phenol than were obtained when round PET f iber web or
Estron filter tow were used as filter substrates. This
WO 92/05713 PC~r/US91/07109
~,.
2~19~17~ 44-
superior phenol removal efficiency was obtained even
though the 4SW PET fiber web filters had consistantly
lower },resDu-~ drops than the filters made from either
round PET fiber web or Estron filter tow and lower
S welg _: ~ n ~i er~ m~de f r_ rou~d l~T f iber web .
WO 92/0~7t3 PCI'/US91/~7tO9
~ ' ~
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WO 92/û5713 PCI /US91/07109
., --
20~21~6 _ 46 -
The invention has been described in detail with
particular reference to the preferrred ~"~ho~ ts
thereof, but it will be understood that variations and
modifications can be effected within the spirit and
5 scope of the invention. All of the U. S . patents cited
herein are hereby incorporated herein by ref erence in
their entirety.
