Note: Descriptions are shown in the official language in which they were submitted.
CA 02199606 1999-OS-28
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CHEWING GUM BASE MANUFACTURING PROCESS USING PLURALITY OF FILLER
FEED INLET LOCATIONS
FIELD OF THE INVENTION
This invention is directed to a continuous
process for the manufacture of chewing gum bases.
HACRGROUND OF THE INVENTION
A typical chewing gum base includes one or more
elastomers, one or more fillers, one or more elastomer
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solvents, softening agents and optional plastic polymers
and miscellaneous colors, flavors and antioxidants. Due
primarily to the difficulty in melting and dispersing the
elastomers homogeneously among the other gum base
ingredients, gum base manufacture has typically been a
tedious and time-consuming batch process. For example,
one such conventional process uses a sigma blade batch
mixer having a front to rear blade speed ratio of 2:1,
and a mixing temperature of about 80-125C.
In this conventional process, initial portions
of elastomer, elastomer solvent and filler are added to
the heated sigma blade mixer and blended until the
elastomer is melted or smeared and thoroughly mixed witi
the elastomer solvent and fillers. Then the remaining
portions of elastomer, elastomer solvent, softening
agents, fillers and other ingredients are added sequenti-
ally, in a stepwise fashion, often with sufficient time
for each stepwise addition to become completely mixed
before adding more ingredients. Depending on the
composition of the particular chewing gum bases and, in
particular, the amount and type of elastomer, consider-
able patience may be required to insure that each
ingredient becomes thoroughly mixed. Overall, anywhere
from one to four hours of mixing time can be required to
make one batch of chewing gum base using a conventional
sigma blade mixer.
After mixing, the molten gum base batch must be
emptied from the mixer into coated or lined pans, or
pumped to other equipments such as a holding tank or a
filtering device, then extruded or cast into shapes, and
allowed to cool and solidify, before being ready for use
in chewing gum. This additional processing and cooling
requires even more time.
Various efforts have been undertaken to try to
simplify and reduce the time required for gum base
manufacture. European Patent Publication No. 0 273 809,
in the name of General Foods France, discloses a process
,"
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for making nonadhesive chewing gum base by blending
elastomer and filler components together in an industrial
mill type mixer to form a nonadhesive premix, dividing
the premix into fragments, and blending the premix
fragments and at least one other nonadhesive gum base
component together in a powder mixer. Alternatively, the
premix fragments and other base components can be added
to an extruder along with other chewing gum components to
accomplish direct manufacture of chewing gum.
French Patent Publication No. 2 635 441, also
in the name of General Foods France, discloses a process
for making a gum base concentrate using a twin screw
extruder. The concentrate is prepared by mixing high
molecular weight elastomers and plasticizers in desired
proportions and feeding them into the extruder. Mineral
fillers are added to the extruder downstream of the feed
inlet of the elastomer/plasticizer blend. The resulting
gum base concentrate has a high level of elastomers. The
concentrate can then be mixed with the other gum base
ingredients to provide a complete gum base.
U.S. Patent No. 3,995,064, issued to Ehrgott et
al., discloses the continuous manufacture of gum base
using a sequence of mixers or a single variable mixer.
U.S. Patent No. 4,187,320, issued to Koch et
al., discloses a two stage process for preparing a
chewing gum base. In the first stage, a solid elastomer,
an elastomer solvent, and an oleaginous plasticizes are
combined and mixed together under high shear. In the
second stage, a hydrophobic plasticizes, a non-toxic
vinyl polymer, and an emulsifier are added to the mixture
and mixed using high shear.
U.S. Patent No. 4,305,962, issued to Del Angel,
discloses an elastomer/resin masterbatch formed by mixing
a finely ground ester gum resin with a latex elastomer to
form an emulsion, coagulating the emulsion using sodium
chloride and sulfuric acid, separating the coagulated
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solid crumbs from the,liquwd-phase, washing the solid
~
crumbs, and removing t~e
excess water.
U.S. Patent No. 4,459,311, issued to DeTora et
al., discloses making gum base using two separate mixers
- a high intensity mixer for pre-plasticizing the
elastomer in the presence of a filler, followed by a
medium intensity mixer for ultimately blending all the
gum base components together.
U.S. Patent No. 4,968,511, issued to D'Amelia
et al., discloses that chewing gum can be made directly
in a one-step compounding process (without making an
intermediate gum base) if certain vinyl polymers are used
as the elastomer portioiz.
Several publications disclose that a continuous
extruder can be used to make the ultimate chewing gum
product after a separate process has previously been used
to make the chewing gum base. These publications include
U.S. Patent No. 5,135,760, issued to Degady et al.; U.S.
Patent No. 5,045,325, issued to Lesko et al., and U.S.
Patent No. 4,555,407, issued to Kramer et al.
Notwithstanding the prior efforts described
above, there is a need and desire in the chewing gum
industry for a continuous process which can effectively
and efficiently be used to make a variety of complete
chewing gum bases without limiting the type or quantity
of elastomer employed, and without requiring preblending
or other pretreatment of the elastomer.
Continuous gum base manufacturing processes,
while desirable, present a number of difficulties. One
of these is that continuous equipment has a given
processing length once set up for operation. This length
is limited in practice by what is commercially available,
and is often less than what may be desired from the gum
base manufacture's standpoint. As a result, continuous
mixing operations have less degrees of freedom than
traditional batch processes. For example, in a batch
process, if longer mixing times are needed, it is a
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simple matter. to continue mixing. However, the residence
time in a continuous mixer is a function of the operating
speed and feed rates. Therefore, to change the mixing
time, some other factor must be adjusted and
accommodated. Further, in a batch process, additional
ingredients can be added at any time. Commercial
continuous mixers have a limited number of feed inlets at
fixed positions. Therefore the additional ingredients
can be added at only preset points in the mixing process.
Also, in a batch mixer, dispersive and
distributive mixing can be independently varied and
controlled. On a continuous mixer, changes to one type
of mixi:~g will of ten also affect the other type of
mixing. If the amount of the machine used for high shear
mixing is increased, there is less machine available for
distributive mixing. Also, if the speed is increased,
heat may be generated beyond the ability of the cooling
capabilities of the equipment.
One of the particular problems that has been
encountered during development of continuous gum base
manufacturing processes is that the properties of the
chewing gum base, particularly the softness of the chew,
is a function of the gum base ingredients and the mixing
conditions that are applied to those ingredients.
However, the mixing conditions are also a function of the
gum base ingredients, as well as the type of mixing
elements being used, the temperature and viscosity of the
ingredients and the fullness of the mixer barrel. For
example, if there is a high content of filler in the
base, more aggressive mixing occurs in the mixer because
the filler acts as an abrasive. Conversely, if the
filler level in the gum base is low, the mixing is less
aggressive, and may not produce sufficient dispersive
mixing of the elastomer.
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BUMMARY OF THE INVENTION
It has been discovered that one way to control
the mixing process, particularly during dispersive mixing
where hard elastomers are masticated, yet at the same
time provide all of the ingredients desired in the
chewing gum base, is to add the filler at a plurality of
feed inlet locations in the continuous mixing process.
In one aspect, the invention is a process for
continuously producing a chewing gum base comprising the
steps of continuously adding chewing gum base
ingredients, including a hard elastomer, filler and one
or more lubricating agents, into a continuous blade and
pin mixer having a plurality of spatially separated feed
inlets, at least a portion of the hard elastomer and a
portion of the filler being introduced into the mixer
through one or more first feed inlets and a portion of
the filler being introduced into the mixer through one or
more second feed inlets located downstream of the first
feed inlets; subjecting the chewing gum base ingredients
to continuous mixing operations within the mixer, thereby
producing a chewing gum base; and continuously
discharging the chewing gum base from the mixer while
chewing gum base ingredients continue to be introduced
and mixed within.
In a second aspect, the invention is a process
for continuously producing a chewing gum base comprising
the steps of continuously adding chewing gum base
ingredients, including a hard elastomer, filler and one
or more lubricating agents, into a continuous mixer
having at least one dispersive mixing zone and at least
one distributive mixing zone and a plurality of spatially
separated feed inlets, at least a portion of the hard
elastomer and a portion of the filler being introduced
into the mixer through one or more feed inlets located
before the end of the dispersive mixing zone and a
portion of the filler being introduced into the mixer
through one or more feed inlets located downstream of the
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dispersive mixing zone and before the end of the
distributive mixing zone, the ratio of the amount of
filler added before the end of the dispersive mixing zone
to the amount of filler added downstream of the
dispersive mixing zone being optimized so that the gum
base contains a desired amount of filler and the
dispersive mixing is effective to properly masticate the
hard elastomer; subjecting the chewing gum base
ingredients to continuous mixing operations within the
mixer, thereby producing a chewing gum base; and
continuously discharging the chewing gum base from the
mixer while chewing gum base ingredients continue to be
introduced and mixed w i thi:. the r~ixzr .
In a third aspect, the invention is a process
for the continuous manufacture of chewing gum base in
which chewing gum base ingredients, including a hard
elastomer, filler and one or more lubricating agents, are
continuously added into the continuous mixer and mixed
therein to produce a chewing gum base which is
continuously discharged from the mixer while chewing gum
base ingredients continue to be introduced and mixed
within the mixer, and in which the continuous mixer has
at least one dispersive mixing zone, at least one
distributive mixing zone downstream of the dispersive
mixing zone and a plurality of spatially separated feed
inlets, the method comprising the steps of adding at
least a portion of the hard elastomer, at least a portion
of the lubricating agents and a portion of the filler
through one or more feed inlets located before the end of
the dispersive mixing zone; adding a portion of the
filler through one or more feed inlets downstream of the
dispersive mixing zone and before the end of the
distributive mixing zone; and optimizing the ratio of the
amount of filler added in each of those locations so that
the gum base produced contains a desired amount of filler
and the mixing process results in an optimized texture of
the gum base.
WO 96108161 PCT/US95103229
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In a fourth.'a~pect, the invention is a process
for continuously producing a chewing gum base comprising
the steps of continuously adding chewing gum base
ingredients, including a hard elastomer, filler and one
or more lubricating agents, into a continuous mixer
comprising a plurality of spatially separated feed
inlets, the filler being added at a plurality of the feed
inlets; controlling the temperature of the mixer so that,
at steady state, the peak temperature is over 250°F;
subjecting the chewing gum base ingredients to continuous
mixing operations within the mixer, thereby producing a
chewing gum base; and continuously discharging the
chewing guru base from the mixer while chewing gum base
ingredients continue to be introduced and mixed within
the mixer.
The invention has numerous advantages. First,
chewing gum base is produced in a continuous process. If
desired, the output can be used to supply a continuous
chewing gum production line or, if sufficient mixing can
be accomplished in the first part of the mixer, the
complete chewing gum can be produced in one mixer.
Second, the average residence time for gum base
ingredients is reduced from hours to minutes. Third, all
of the necessary addition and gum base compounding steps
can be performed in sequence, preferably using a single
continuous mixing apparatus. Fourth, the preferred
embodiment provides improved metering and mixing of
intermediate and low viscosity gum base ingredients by
adding these ingredients in the liquid state under
pressure. Fifth, the invention is effective for a wide
range of gum base compositions, including different gum
base elastomers and elastomer percentages, without
requiring preblending or other pretreatment of the
elastomers. Sixth, the gum base can be produced on
demand, eliminating finished base inventory. This allows
maximum flexibility to react to market demands and
formula changes. Seventh, high quality gum bases,
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WO 96!08161 PCT/US95/03229
_ g _
including those containing high levels of fats, oil
and/or low melting point waxes, can be made on a
continuous basis.
The foregoing and other features and, advantages
of the invention will become further apparent from the
following detailed description of the presently preferred
embodiments, read in conjunction with the accompanying
examples and drawings.
BRIEF DEBCRIPTION OF THE DRAWINGS
FIG. 1 depicts a schematic representation of a
twin screw extruder set up for use in practicing the
present invention.
FIG. 2 depicts a set of shearing disks used in
5 the extruder of~FIG. 1.
FIG. 3 depicts a set of toothed elements used
in the extruder of FIG. 1.
FIG. 4 depicts a set of kneading disks used in
the extruder of FIG. 1.
FIG. 5 depicts a plurality of kneading disks,
set up in a helical fashion, to form kneading blocks.
FIGS. 6a-a depict schematic sequential
representations of gum base ingredients during the mixing
process.
FIG. 7 is a perspective view of a single flat
mixing paddle as used in practicing another embodiment of
the invention.
FIG. 8 is a side view of the mixing paddle of
FIG. 1.
FIG. 9a is a front view of the mixing paddle of
FIG. 7, shown at zero degrees rotation (referred to as
the no. 1 position).
FIG. 9b is a front view of the mixing paddle of
FIG. 7, shown at 45 degrees counter-clockwise rotation
(referred to as the no. 2 position).
FIG. 9c is a front view of the mixing paddle of
FIG. 7, shown at 90 degrees counter-clockwise rotation
(referred to as the no. 3 position).
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FIG. 9d is a front view of the mixing paddle of
FIG. 1, shown at 135 degrees counter-clockwise rotation
(referred to as the no. 4 position).
FIG. 10a is a perspective view of a feeding
element (not a paddle element) used in the feed areas of
a paddle mixer.
FIG. 10b is a front view of the feed element of
FIG. 10a.
FIG. lla is a perspective view of a forward
helical mixing paddle which can be used in a paddle
mixer.
FIG. ilb is a front view of the forward helical
mixing paddle of FIG. ila.
FIG. llc is based on a top view of the forward
helical mixing paddle of lla, showing only the top
intersection line 92 superimposed over the bottom
intersection line 90, and a reference line 91.
FIG. 12a is a perspective view of a reverse
helical mixing paddle which can be used in a paddle
mixer.
FIG. 12b is a front view of the reverse helical
mixing paddle of FIG. 12a.
FIG. 12c is based on a top view of the reverse
helical mixing paddle of FIG. 12a, showing only the top
intersection line 92 superimposed over the bottom
intersection line 90, and a reference line 91.
FIG. 13 is a perspective view of an overall
paddle mixing configuration of a paddle mixer.
FIG. 14 is a schematic illustration of a barrel
and feeder arrangement which can be used in conjunction
with the paddle mixer configuration shown in FIG. 13.
FIG. 15 is a cross-sectional view taken along
line 15-15 of FIG. 14, showing the relationship between
the rotating paddles and the barrel wall.
FIG. 16 is a schematic illustration of two
paddle mixers arranged in series.
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FIG. 17 is a partial exploded perspective view
of a Buss high efficiency, blade-and-pin mixer used to
practice another embodiment of the invention,
illustrating a mixing barrel and mixing screw
arrangement.
FIG. 18a is a perspective view of an on-screw
element used on the upstream side of a restriction ring
assembly in the high efficiency mixer of FIG. 17.
FIG. 18b is a perspective view of an on-screw
element used on the downstream side of the restriction
ring assembly in the high efficiency mixer of FIG. 17.
FIG. 18c is a perspective view of a restriction
r ing asse.«bly used iu tire high ef f iciency mixer of
FIG. 17.
FIG. 19 is a perspective view showing the
relative positioning of the elements of FIGS. 18a, 18b
and 18c in the high efficiency mixer of FIG. 17.
FIG. 20 is a perspective view of a low-shear
mixing screw element used in the high efficiency mixer of
FIG. 17.
FIG. 21 is a perspective view of a high-shear
mixing screw element used in the high efficiency mixer of
FIG. 17.
FIG. 22 is a perspective view of a barrel pin
element used in the high efficiency mixer of FIG. 17.
FIG. 23 is a schematic diagram of an
arrangement of mixing barrel pins and ingredient feed
ports used with the high efficiency mixer of FIG. 17.
FIG. 24 is a schematic diagram of a presently
preferred mixing screw configuration used with the high
efficiency mixer of FIG. 17.
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DETAILED DEBCRIPTION
12 -
3F ~'~L'HE:~ DRAWINGB AND
As noted earlier, gum base ingredients play a
functional role during both mixing of the gum base and in
the final chew characteristics of the chewing gum made
from the base. During high shear, dispersive mixing, the
filler acts to increase the shear. Some of the other gum
base ingredients act as lubricating agents, reducing the
shear. Most elastomer solvents, soft elastomers, plastic
polymers and softening agents generally act as
lubricating agents in continuous gum base manufacturing
processes. Some lubricating agents such as
polyisobutylene and the elastomer solvents cause the
elastomer to disentangle, while others are not miscible
with the elastomer and act only to lubricate the mixing
and shearing operations.
To get an optimized shear in a limited amount
of mixing space inside of continuous mixers, the amount
of filler introduced into the mixer prior to the
distributive mixing zone may therefore often be less than
the amount of the filler desired in the final gum base.
Thus, the methods of the present invention introduce the
filler at a plurality of feed inlets so that a desired
amount of shear can be achieved in a limited portion of
the mixer, yet the final gum base can include all of the
elastomer, filler and lubricating agents desired from a
sensory and cost standpoint. Preferably, the lubricating
agent added before the dispersive mixing will be one that
acts as a solvent for the hard elastomer.
In one embodiment of the invention, it is
preferable if the dispersive mixing can be accomplished
in the first 40% of the barrel length of a continuous
mixer. Therefore, in one embodiment of the invention,
the first portion of filler will be introduced within the
first 40% of the barrel length, and the second portion is
added in the last 60% of the barrel length.
The invention also contemplates a method of
optimizing the process for making chewing gum base in a
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continuous process by adjusting the ratio of filler being
introduced at the different feed inlets until the proper
mixing is achieved. For instance, in one set of
experiments, the same gum base ingredients can be added
at the same places in the mixer for each run, except that
the filler is split at various ratios as it is added at
two different points to the mixer. The desired ratio
that will result in optimum processing, and the range of
ratios that will be experimented with, will of course
depend on the gum base formulation, the type of mixer
being used, and the arrangement of mixing elements in the
mixer.
The chewing gum base made by the process of the
present invention will be the same as bases made by
conventional processes, and can thereafter be made into
conventional chewing gums, including bubble gum, by
conventional methods. The methods of production are well
known and therefore not repeated here. Of course,
specialized chewing gum, such as nonadhesive chewing gum
and bubble gum, will use specialized gum base
ingredients. However, those gum base ingredients can be
combined using the processes herein described.
In general, a chewing gum composition typically
comprises a water-soluble bulk portion, a water-insoluble
chewable gum base portion and typically water-insoluble
flavoring agents. The water-soluble portion dissipates
with a portion of the flavoring agent over a period of
time during chewing. The gum base portion is retained in
the mouth throughout the chew.
The insoluble gum base generally comprises
elastomers, elastomer solvents, softening agents and
inorganic fillers. Plastic polymers, such as polyvinyl
acetate, which behave somewhat as plasticizers, are also
often included. Other plastic polymers that may be used
include polyvinyl laurate, polyvinyl alcohol and
polyvinyl pyrrolidone.
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Elastomers may constitute about 5 to about 95
percent by weight of the gum base, preferably between 10
and 70 percent by weight and most preferably between 15
and 45 percent by weight. Elastomers may include
polyisobutylene, butyl rubber (isobutylene-isoprene
copolymer), styrene butadiene rubber, polyisoprene and
butadiene rubber, as well as natural rubbers such as
smoked or liquid latex and guayule, as well as natural
gums such as jelutong, lechi caspi, perillo, massaranduba
balata, massaranduba chocolate, nispero, rosindinha,
chicle, gutta hang kang or mixtures thereof.
Elastomer used in chewing gum base can
generally be categorised as hard elastomers or soft
elastomers. Hard elastomers, which are most commonly
butyl rubber and styrene butadiene rubber, generally have
a high molecular weight, typically a Flory molecular
weight over 200,000. A typical butyl rubber used in
chewing gum base has a Flory molecular weight of about
400,000. Hard elastomers are those which require high
shear, dispersive mixing to be utilized in chewing gum
base. Hard elastomers generally do not flow at room
temperature, even over an extended period of time, and
are not pumpable even when heated to temperatures just
below which substantial degradation occurs.
Soft elastomers have a lower molecular weight,
typically a Flory molecular weight under 100,000.
Polyisobutylene and polybutadiene are typically soft
elastomers. A typical polyisobutylene used in chewing
gum base has a Flory molecular weight of about 53,000.
Soft elastomers are generally pumpable at temperatures
normally used to make chewing gum base, and will flow at
room temperature, though often very slowly.
In addition to Flory molecular weight,
sometimes a Stodinger molecular weight is specified.
Stodinger molecular weights are generally 1/3 to 1/5 of
Flory molecular weights. For example, the
polyisobutylene having a Flory molecular weight of 53,000
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has a Stodinger molecular weight of about 12,000.
Sometimes number average or weight average molecular
weights are reported, or the measurement method is not
reported. In such instances, the above recitation of the
functionality of the elastomer and how.they are mixed in
producing the chewing gum base can generally be used to
classify the elastomer as hard or soft.
Elastomer solvents may constitute from about 0
to about 75 percent by weight of the gum base, preferably
5 to 45 percent by weight and most preferably 10 to 30
percent by weight. Elastomer solvents include natural
rosin esters such as glycerol ester of wood rosin,
glycercl ester of partially hydrogenated rosi~~, yiycerai
ester of polymerized rosin, glycerol ester of partially
dimerized rosin, glycerol ester of rosin, pentaerythritol
esters of partially hydrogenated rosin, methyl and
partially hydrogenated methyl esters of rosin,
pentaerythritol ester of rosin, resin ester of glycerol
abietate or mixtures thereof. Elastomer solvents also
include synthetics such as terpene resins derived from
alpha-pinene, beta-pinene and/or d-limonene.
Softening agents include oils, fats, waxes and
emulsifiers. Oils and fats, sometimes referred to as
plasticizers, include tallow, lard, hydrogenated and
partially hydrogenated vegetable oils, such as soybean
oil, cotton seed oil, palm oil, palm kernel oil, coconut
oil, sunflower oil and corn oil, cocoa butter, and lipids
made from triglycerides of fatty acids. Commonly
employed waxes include polywax, paraffin,
microcrystalline and natural waxes such as candelilla,
beeswax and carnauba. Paraffin waxes may be considered
to be plasticizers. Microcrystalline waxes, especially
those with a high degree of crystallinity, may be
considered as bodying agents or textural modifiers.
Emulsifiers, which also sometimes have
plasticizing properties, include glycerol monostearate,
lecithin, mono and diglycerides of fatty acids, glycerol
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mono and distearate, triacetin, acetylated monoglyceride,
and glycerol triacetate.
The gum base typically also includes a filler
component. The filler component may be calcium
carbonate, magnesium carbonate, talc, dicalcium phosphate
or the like. The filler may constitute between about 5
and about 60 percent by weight of the gum base.
Preferably, the filler comprises about 5 to about 50
percent by weight of the gum base.
Further, gum bases may also contain optional
ingredients such as antioxidants, colors and flavors.
The temperature attained in the mixer often
varies over the length of the :aixer. Ths peak
temperature in the dispersive mixing zone where high
shear mixing elements are located, will preferably be
over 175F, more preferably over 250F and most
preferably over 300F, and even 350F for some gum base
manufacturing processes.
The insoluble gum base may constitute between
about 5 to about 80 percent by weight of the gum. More
typically the insoluble gum base comprises between 10 and
50 percent by weight of the gum and most often about 20
to about 35 percent by weight of the gum.
The water soluble portion of the chewing gum
may include softeners, bulk sweeteners, high intensity
sweeteners, flavoring agents and combinations thereof.
Softeners are added to the chewing gum in order to
optimize the chewability and mouth feel of the gum. The
softeners, which are also known as plasticizers or
plasticizing agents, generally constitute between about
0.5-15% by weight of the chewing gum. The softeners may
include glycerin, lecithin, and combinations thereof.
Aqueous sweetener solutions such as those containing
sorbitol, hydrogenated starch hydrolysates, corn syrup
and combinations thereof, may also be used as softeners
and binding agents in chewing gum.
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Bulk sweeteners constitute between 5-95% by
weight of the chewing gum, more typically 20-80% by
weight of the chewing gum and most commonly 30-60% by
weight of the chewing gum. Bulk sweeteners may include
both sugar and sugarless sweeteners and components.
Sugar sweeteners may include saccharide containing
components including but not limited to sucrose,
dextrose, maltose, dextrin, dried invert sugar, fructose,
levulose, galactose, corn syrup solids, and the like,
alone or in combination. Sugarless sweeteners include
components with sweetening characteristics but are devoid
of the commonly known sugars. Sugarless sweeteners
incl~.Zd~ but 4rv nVt limited to sugar alcohols such as
sorbitol, mannitol, xylitol, hydrogenated starch
hydrolysates, maltitol, and the like, alone or in
combination.
High intensity sweeteners may also be present
and are commonly used with sugarless sweeteners. When
used, high intensity sweeteners typically constitute
between 0.001-5% by weight of the chewing gum, preferably
between 0.01-1% by weight of the chewing gum. Typically,
high intensity sweeteners are at least 20 times sweeter
than sucrose. These may include but are not limited to .
sucralose, aspartame, salts of acesulfame, alitame,
saccharin and its salts, cyclamic acid and its salts,
glycyrrhizin, dihydrochalcones, thaumatin, monellin, and
the like, alone or in combination.
Combinations of sugar and/or sugarless
sweeteners may be used in chewing gum. The sweetener may
also function in the chewing gum in whole or in part as a
water soluble bulking agent. Additionally, the softener
may provide additional sweetness such as with aqueous
sugar or alditol solutions.
Flavor should generally be present in the
chewing gum in an amount within the range of about 0.1-
15% by weight of the chewing gum, preferably between
about 0.2-5% by weight of the chewing gum, most
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preferably between about 0.5-3% by weight of the chewing
gum. Flavoring agents may include essential oils,
synthetic flavors or mixtures thereof including but not
limited to oils derived from plants and fruits such as
citrus oils, fruit essences, peppermint oil, spearmint
oil, other mint oils, clove oil, oil of wintergreen,
anise and the like. Artificial flavoring agents and
components may also be used in the flavor ingredient of
the invention. Natural and artificial flavoring agents
may be combined in any sensorially acceptable fashion.
Optional ingredients such as colors,
emulsifiers, pharmaceutical agents and additional
flascring agents may also be included in chewing gum.
The preferred process of the present invention
may be carried out with a variety of continuous mixing
equipment. In some embodiments of the invention, more
than one piece of continuous mixing equipment will be
coupled in series. As used in the claims, the terra na
continuous mixers means one mixer or a plurality of
mixers in series. Three specific types of continuous
mixing equipment are described in detail below and are
shown in the attached drawings: twin screw extruders,
paddle mixers and blade-and-pin mixers, which are
specialized single screw extruders. Extruders are
preferred for use in the present invention, particularly
the blade-and-pin mixer.
A. Twin Screw Extruders
In one embodiment, the invention may be carried
out on a twin screw extruder such as depicted
schematically in FIG. 1. The twin screw extruder used to
practice the preferred embodiment of the invention will
be set up with several different feed inlet locations
where chewing gum base ingredients can be added. The
screws inside the barrel of the extruder are equipped
with different types of elements along the length of the
screws. The different mixing zones are sometimes
z~ ~~~Q~
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referred to as processing zones, and described by the
type of elements employed in the zones. The barrel is
typically made up of different sections. These sections
may be heated or cooled independent of other sections.
Heating and cooling is thus typically done by region of
the extruder barrel, which generally coincides with the
barrel sections. These regions of heating or cooling may
or may not coincide with processing zones, depending on
the lengths of the barrel sections and the elements in
the processing zones.
While different equipment manufacturers make
different types of elements, the most common types of
elements include conveying elements, campressior~
elements, reverse conveyance elements, homogenizing
elements such as shearing disks and toothed elements, and
kneading disks and blocks. Conveying elements generally
have flights spiraling along the elements with wide gaps
between the flights. These elements are used at~feed
inlet zones to quickly move material into the body of the
extruder. Compression elements have flights with a pitch
that narrows as the material moves along the flights.
This results in compression and high pressure in the
forward direction, which is required to force material
downstream and through the other elements. Reverse
conveyance elements have flights that are angled opposite
those of the conveying elements. The flights rotate in a
direction that would force material upstream. These
elements provide a high back pressure and slow down
movement of the material through the extruder. Of
course, the extruded material still works its way
opposite the flights to move downstream through the
reverse elements. A reverse helical arrangement of
kneading blocks can accomplish a similar result.
Shearing disks, as their name implies, impart
high shearing forces on the material in the extruder,
resulting in highly dispersive mixing. In a twin screw
extruder, the shearing disks opposite one another on the
2lssso=
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two different screws have close fitting disk/slot
elements, as depicted in FIG. 2. Toothed elements, as
depicted in FIG. 3, have gear-like teeth that oppose a
cylindrical spacer shaft on the other screw. Toothed
elements impart highly distributive mixing. Often the
toothed elements are made in matched sets, with a
cylindrical shaft portion and a toothed portion as one
unit. Kneading disks, as shown in FIG. 4, have an
elliptical shape, and produce a kneading action in the
material passing through the extruder. Often a plurality
of kneading disks will be placed next to each other in a
helical arrangement, as shown in FIG. 5, referred to as
kn~a,.i..g blVc..s.
Highly distributive mixing can also be
accomplished using reverse conveyance elements that have
portions missing from the flights to allow flow counter
to the direction of compression. These missing portions
may be arranged as a groove through the flights cut
parallel to the length of the element. Also, kneading
blocks followed by reverse conveyance elements, to build
up high back pressure, also produce highly distributive
mixing.
Mixing-restriction elements produce a high back
pressure and some mixing without overly restricting
throughput. For this reason, nozzles or orifices are not
suitable as mixing-restriction elements. As noted above,
reverse conveyance elements provide back pressure, and
are thus mixing-restriction elements. Shearing disks,
like those shown in FIG. 2, also produce a high back
pressure and are thus another example of a mixing-
restriction element.
The high back pressure is important so that
other elements, such as those that produce highly
distributive or highly dispersive mixing, will be able to
function properly. Thus in the preferred embodiment of
the invention, mixing-restriction elements are used after
each mixing zone. It is most preferable to use a mixing-
WO 96/08161 ~ PCT/US95/03229
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restriction element just prior to the gum base exiting
the extruder.
These various types of elements, and other
elements useful in twin screw extruders, are well known
in the art and are commercially available. The elements
are often specifically designed for the different types
of commonly available twin screw extruders, which include
co-rotation, counter rotation, intermeshing and
tangential twin screw extruders. Elements intended for
similar functions will vary in design depending on the
type of extruder for which they are intended.
One specif is type of element f or a specif is
brand cf extruder is a non-intermeshing polygon eiemeni
sold by the Farrel Corporation, 25 Main Street, Ansonia,
Conn. 06401, for the Farrel-Rockstedt co-rotating twin
screw extruder. It is believed that the non-intermeshing
polygons produce dispersive mixing.
In preferred embodiments of the invention, the
dispersive mixing disentangles the elastomers with a
minimum amount of degradation of the polymer chains.
Thus, while dispersive mixing will inevitably reduce the
molecular weight of the polymer, it is preferable to
control the dispersive mixing operation to minimize this
molecular weight reduction. Preferably, the average
molecular weight will not be reduced below the average
molecular weight of the same polymers mixed into gum base
using conventional processes.
An adequate dispersive mixing will produce a
smooth, rubbery fluid, with no detectable lumps of
rubber. If only a few lumps of rubber are present they
may be screened out or dispersed during subsequent mixing
steps. However, if the number or size of lumps is
excessive, or the processed elastomers and fillers are in
the form of an agglomeration or grainy mass, the
dispersive mixing applied is inadequate.
The distributive mixing should be sufficient to
produce a homogeneous gum base, rather than a material
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WO 96108161 ~ PCT/US95/03229
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that appears to be psweatingn, or that has a marbled or
Swiss cheese texture. In the preferred embodiment of the
invention, the highly distributive mixing is sufficient
to incorporate softening agents, particularly fats, oils
and waxes, to the same degree these softening agents are
incorporated in conventional chewing gum base
manufacturing processes.
As shown in FIG. 1, for practicing an
embodiment of the invention, a twin screw extruder 10 is
set up with a first feed inlet location 12 adjacent a
first processing zone 21 fitted with conveying elements
31, conveying and compression elements 32 and compression
elements 35. The second processing zone 23 is equipped
with a combination of toothed elements 33, as depicted in
FIG. 3, and several sets of shearing disks 34, as
depicted in FIG. 2. At the end of the second processing
zone 23 the extruder 10 is equipped with a port 16 which
is connected to a vacuum source (not shown). The third
processing zone 24 contains additional conveying elements
31, conveying and compression elements 32 and compression
elements 35. A second feed inlet 13 is provided in the
extruder adjacent this second set of conveying
elements 31, for feeding additional gum base ingredients
into the third processing zone 24. Feed inlet 13 allows
for the addition of powdered ingredients as well as
liquid ingredients from pump 41. The fourth processing
zone 25 is fitted with kneading disks 36. At the
beginning of the fifth processing zone 26, the twin screw
extruder 10 has another inlet 15 connected to a pump 43
and a feed inlet 14 in the form of a port connected to a
side feeder 42, which may be a single or twin screw
extruder, or even a gear pump which can generate high
pressure. The fifth processing zone 26 is fitted with
conveying elements 31, conveying and compression elements
32 and compression elements 35, which force the gum base
ingredients into the sixth and final processing zone 28.
Zone 28 contains two sets of toothed elements 33,
2I996p6
WO 96!08161 PCT/US95/03229
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followed by reverse elements 39 and shearing disks 34.
After passing through the shearing disks 34, the gum base
ingredients exit the extruder l0.
It may be preferable to heat some of the
ingredients, either to melt them or to lower their
viscosity. As shown in FIG. 1, the extruder 10 may be
set up with heated tanks 44 and 45, connected
respectively to pumps 41 and 43, for this purpose. Other
commonly used equipment, such as equipment to monitor the
temperature and heat or cool the extruder, is not shown
in FIG. 1. The equipment will also include conventional
weighing and feeding devices for continuously adding
granulated or powdered ingredients. All of the
ingredients are preferably fed into the extruder by
equipment that is controlled to operate at a steady
state; although during startup it may be preferable to
start feeding some ingredients before others, and to feed
the ingredients in at different rates than those desired
for steady-state operation.
It will be understood that FIG. 1, as a
schematic representation, shows the various components in
their respective order from the standpoint of flow
through the extruder 10. Typically the screws are
mounted in a horizontal side-to-side position and feed
inlets, especially those open to the atmosphere like the
inlet 12 and 13, are placed vertically above the screws.
While the arrangement of FIG. 1 is preferred
for particular gum bases, other arrangements may be
preferred for other gum bases. FIG. 1 depicts an
extruder with three general areas of ingredient addition
and six processing zones. For some gum bases, two, four
or more ingredient feeding zones may be used, with
different numbers of processing zones. FIG. 1 also
depicts the use of one set each of long conveying
elements 31, conveying and compression elements 32 and
compression elements 35 in the first processing zone 21,
a short set of conveying and compression elements 32 in
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zones 24 and 26, and a short set of conveying elements 31
and compression elements 35 in zone 26. In reality, one,
two or more elements of different types and length may be
used in these zones. FIG. 1 also depicts one set of
toothed elements 33 and three sets of shearing disks 34
in zone 23, but different numbers of these elements, or
different elements all together, may be used. Likewise
in zones 25 and 28, different types of elements that
produce distributive mixing may be used, dependent on the
gum ingredients being mixed in those zones and the type
of extruder being used.
FIGS. 6a-a represent the state of various gum
base ingredients as they are compounded into chewing gui~
base. At the beginning, as shown in FIG. 6a, the high
molecular weight (hard) elastomer 51 and medium molecular
weight elastomer 52 are both in the form of granules or
particles in which the elastomer molecules are tightly
bound together. The filler 53 is in particulate form,
but may not be homogeneously mixed with the elastomers 51
and 52. The elastomer solvent 54 may be present in the
form of droplets. As mixing begins, depicted in FIG. 6b,
the elastomer solvent 54 becomes associated with the
elastomers 51 and 52. With the presence of the filler
53, elastomer solvent 54 and heat, the granules begin to
come apart into individual elastomer molecules. Also,
the filler 53 becomes more evenly distributed, and may
have its particle size reduced. As the process
continues, the elastomers 51 and 52 become disentangled,
as shown in FIG. 6c. This disentangling is the result of
subjecting the elastomers 51 and 52 to highly dispersive
mixing.
After this step, the lower viscosity
ingredients, such as polyvinyl acetate 55, may be added,
as shown in FIG. 6d. Initially, this material will also
be in discrete particles, or droplets as it melts.
Further mixing and further ingredient additions, such as
waxes 56 and emulsifiers 57, are subjected to distrib-
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WO 96/08161 PCT/US95/03229
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utive mixing, as depicted in FIG. 6e. Continued highly
distributive mixing produces a homogeneous chewing gum
base, wherein discrete particles or droplets are not
detectible by sensory perception.
The elastomer may be added at the first feed
inlet 12 along with elastomer solvent such as resins and
the filler. However, especially lower weight elastomers
may be added at least partially at the second feed inlet
13. Portions of the filler may also be added at the
second feed inlet 13. Polyvinyl acetate may be added via
a powder feeder or the single screw extruder 42, or a
twin screw extruder or gear pump, at the feed inlet port
14, while melted fats and waxes and oils are auued at Ltie
last feed inlet 15. This will result in the filler,
elastomer and some lubricating agents being subjected to
highly dispersive mixing first before lower viscosity
ingredients are added. The toothed elements 33, reverse
elements 39 and shearing disks 34 after feed inlet 15
result in highly distributive mixing of all of the low
viscosity gum base ingredients with the other gum base
ingredients.
A preferred small scale extruder is a model LSM
30.34 counter-rotational, intermeshing and tangential
twin screw extruder from Leistritz, Niirenberg, Germany.
Other acceptable twin screw extruders include the Japan
Steel Works Model TEX30HSS32.5PW-2V intermeshing co- and
counter-rotating twin screw extruder, also known as the
Davis Standard D-Tex Model, distributed by Crompton &
Knowles Corporation, #1 Extrusion Dr., Pawcatuck,
CT 06379, and either the co-rotating or counter-rotating
intermeshing twin screw extruders from Werner &
Pfleiderer Corporation, 663 E. Crescent Ave., Ramsey N.J.
07446. It is preferred to have a long barrel length. A
Werner & Pfleiderer co-rotational twin screw extruder can
go up to a length to diameter (L/D) ratio of 48. The
Japan Steel Works Model TEX30HSS32.5PW-2V extruder may be
equipped to have an L/D of 58.
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WO 96/08161 PCT/US95/03229
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B. Paddle Mixers
Another type of continuous mixer that may be
used to practice the present invention is a paddle mixer.
A mixing paddle 85 having a flat (non-helical)
configuration is shown in FIGS. 7-9. The term "'mixing
paddle"' is defined herein as a four-sided mixing element
having two flat surfaces 86 and 87, and two concave
surfaces 88 and 89. The flat surfaces are parallel to
each other and intersect only the concave surfaces. The
concave surfaces oppose each other and intersect each
other at two lines 90 and 92. A non-circular (preferably
square) opening 94 passes through the center of each
mixing pu~diG V5, i:. a dire,:tion perpendicular to the
flat surfaces 86 and 87, and intersects both flat
surfaces. The openings 94 are used for mounting a
plurality of paddles on rotating shafts, in a
predetermined sequence (FIG. 13).
Referring to FIGS. 9a-d, the mixing paddles 85
can be positioned on a shaft at the same or different
rotational angles relative to each other. For purposes
of the following description, the ~'No. 1 position"' is
defined pursuant to FIG. 9a, wherein a straight line
drawn on the flat surface 87 and intersecting the lines
90 and 92 coincides with a reference line (for example, a
vertical line). The "No. 2 position" is defined pursuant
to FIG. 9b, wherein a straight line drawn on the flat
surface 87 and intersecting the lines 90 and-92 is 45
degrees counter-clockwise from the reference line. The
"No. 3 position" is defined pursuant to FIG. 9c, wherein
a straight line drawn on the flat surface 87 and
intersecting the lines 90 and 92 is 90 degrees counter-
clockwise from the reference line. The "No. 4 position"
is defined pursuant to FIG. 9d, wherein a straight line
drawn on the flat surface 87 and intersecting the lines
90 and 92 is 135 degrees counter-clockwise from the
reference line.
~~ ~~s~s
WO 96/08161 PCT/US95/03229
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Because the paddles 85 in FIGS. 9a-d are
symmetrical, there is no need to further define the
relative rotational positions of the paddles for angles
of 180, 225, 270 and 315 degrees from the reference line.
For example, a paddle having a rotational position of 180
degrees coincides exactly with a paddle having a
rotational angle of zero (FIG. 9a). Similarly, a paddle
having a rotational angle of 225 degrees coincides
exactly with a paddle having a rotation angle of 45
degrees (FIG. 9b); a paddle having a rotational angle of
270 degrees coincides exactly with a paddle having a
rotational angle of 90 degrees (FIG. 9c), and a paddle
ha,rin g a rctuticnal angle of 315 degrees coiriues
exactly with a paddle having a rotational angle of 135
degrees (FIG. 9d).
It is also understood that each mixing paddle
85 will be in constant rotation during operation of the
paddle mixer, due to the rotation of the shafts
supporting the paddles (FIG. 13). For purposes of
describing the mixing paddles in terms of relative
rotational positions (i.e. relative to each other) as
explained above, the reference line should be deemed to
rotate as the paddles rotate. For example, if the mixing
paddles shown in FIGS. 9a-d are positioned sequentially
on a single shaft, and if the shaft is rotated 90
degrees, then the chosen reference line, initially
vertical, would rotate to a horizontal position. In
other words, the relative rotational positions of the
mixing paddles in FIGS. 9a-d, defined respectively as
1-2-3-4, will not change during operation of the paddle
mixer.
Referring to FIGS. l0a and lOb, the method of
the invention also provides for the use of a minor
portion of non-paddle elements known as forward conveying
or feed elements 50. Each feed element 50 has a flat
front surface 48, a flat back surface 49 parallel to the
front surface, and a non-circular (preferably square)
WO 96/08161 ~ PCT/US95/03229
. ~ ~~ r._~ :~ 2 8 _
.>
opening 46 perpendicular to and intersecting the front
and back surfaces. However, unlike the mixing paddles
described above, the feed elements do not have two
concave surfaces intersecting at two lines. Instead,
each feed element 50 includes portions of two alternating
helical channels 47 and 59. The helical channels are
more apparent in FIG. 13 wherein a plurality of feed
elements 50 are combined in sequence on the rotating
shafts 110 to form feed zones in the mixer. The primary
purpose of the feed elements 50 is to convey chewing gum
base ingredients forward to the regions of the mixer
where paddle mixing takes place.
Referring to FIGS. lla and 11b, a type of
mixing paddle known as a forward helical paddle 95 can
also be used with the method of the invention. When
used, the forward helical paddle 95 imparts a slight
forward conveying action while mixing the gum base
ingredients. Like the flat mixing paddles 85, each
forward helical.paddle 95 has two flat surfaces and two
concave surfaces 88 and 89. The flat surfaces are
parallel to each other and intersect only the concave
surfaces. The concave surfaces oppose each other and
intersect at two lines 90 and 92. Again, a non-circular
(preferably square) opening 94 passes through the center
of each mixing paddle 95 and intersects both flat
surfaces.
The difference between the forward helical
paddle 95 and the flat mixing paddle 85 is that, in the
flat mixing paddle 85, the lines 90 and 92 (defining the
intersections of concave surfaces 88 and 89) are parallel
to each other as shown in FIG. 8. In the forward helical
paddle, the line 90 has been rotated counter-clockwise
with respect to the line 92 so that the lines are no
longer parallel, as shown in FIG. llb. Similarly, the
line 92 has been rotated clockwise with respect to the
line 90. The effect of this rotation is to bend the
WO 96/08161 ~ PCT/US95/03229
_ 29 _
concave surfaces 88 and 89 so that these surfaces have a
mildly helical configuration.
Referring to FIGS. 12a and 12b, a type of
mixing paddle known as a reverse helical paddle 96 can
also be used with the method of the invention. When
used, the reverse helical paddle 96 imparts a slight
resistance to forward conveying of the gum base
ingredients while mixing the ingredients. This causes a
locally higher degree of mixer fill and slight elevation
in pressure, in the vicinity of the reverse helical
paddle 96.
The reverse helical paddle 96 is configured in
the same fasrion 4j the forward helical pattern 95
discussed above, except that the lines 90 and 92
(defining the intersections of concave surfaces 88 and
89) are rotated in the opposite directions. Referring to
FIG. 12a, the line 90 has been rotated clockwise with
respect to the line 92, and the line 92 has been rotated
counter-clockwise with respect to the line 90. The
effect of this rotation is to bend the concave surfaces
88 and 89 so that these surfaces have a mild reverse
helical configuration.
The degree of rotation of lines 90 and 92 for
the forward and reverse helical paddles 95 and 96 can be
explained with reference to FIGS. ilc and 12c. In
FIGS. llc and 12c, the helical paddles have been viewed
from above and only the lines 90 and 92 of the paddles
are shown, superimposed one on top of the other. A
reference line 91 is also shown, indicating the positions
of lines 90 and 92 if there were no rotation, as in a
flat paddle 85.
Referring to FIG. llc, the angle na" is the
amount of counter-clockwise rotation of line 90 present
in a forward helical paddle 95. The angle "an should be
between about 5 and about 30 degrees, preferably between
about 10 and about 18 degrees, most preferably about 13
degrees, 53 minutes, 50 seconds. The angle nb" is the
b~ ~, : 'si '~- ' ' , PCT/US95/03229
WO 96/08161
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amount of clockwise rotation of line 92 present in a
forward helical paddle 95. The angle nbn should be
between about 5 and about 30 degrees, preferably between
about l0.and about 18 degrees, most preferably about 13
degrees, 53 minutes, 50 seconds.
Referring to FIG. 12c, the angle nah is the
amount of clockwise rotation of line 90 present in a
reverse helical paddle 96. The angle nan should be
between about 5 and about 30 degrees, preferably between
about 10 and about 18 degrees, most preferably about 13
degrees, 53 minutes, 50 seconds. The angle ~'b~' is the
amount of counter-clockwise rotation of line 92 present
i~ a re~:er~e helical paddle 96. The angle ~bh should
between about 5 and about 30 degrees, preferably between
about 10 and about 18 degrees, most preferably about 13
degrees, 53 minutes, 50 seconds.
Referring to FIG. 13, the mixing paddles and
feed elements are assembled on two parallel shafts 110 in
a predetermined configuration. In the embodiment shown,
for a 5-inch paddle mixer, each of the shafts 110 has an
active length of 36 inches and a square cross-sectional
area of 1.375 inches x 1.375 inches (1.891 square
inches). The parallel shafts 110 are spaced apart at a
distance of 3.5 inches (center to center). The shafts
110 are adapted for co-rotation (rotation in the same
direction) inside a mixing barrel. Each of the shafts
110 supports an identical arrangement of mixing paddles
and feed elements. The mixing paddles and feed elements
on the adjacent shafts may intermesh, as shown in FIG.
13, but do not touch each other, as the shafts rotate.
Each of the shafts 110 is long enough to
accommodate thirty-six inches of elements, each having a
length of 1 inch, a maximum diameter of 4.874 inches and
a minimum diameter of 2 inches. Two or more 1-inch
segments may be combined to make longer elements without
affecting the operation. For instance, the feed elements
50 often have a length of 2 inches. For purposes of the
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invention, a large portion of each shaft should be
covered with mixing paddles. Generally, at least about
40 percent of each shaft should be covered with mixing
paddles. Preferably at least about 50 percent of each
shaft is covered with mixing paddles, most preferably at
least about 60 percent. Of the mixing paddles, a
majority should be flat mixing paddles as opposed to
forward helical or reverse helical paddles. In the
embodiment shown in FIG. 13, 67 percent of the shaft
length is covered with mixing paddles (24 one-inch
elements) and 33 percent of the shaft length is covered
with feed elements (6 two-inch elements).
The mixer confiysration 102 in FiG. i3 inoiucies
two feed zones 325 and 135, and two paddle mixing zones
130 and 150. The specific mixer configuration is
indicated in Table 1 below. In Table 1 and other tables,
the following abbreviations are used:
FC - feed conveying element (each
occupying two 1-inch positions)
FP - flat mixing paddle (each occupying
one 1-inch position)
FH - forward helical mixing paddle (each
occupying one 1-inch position)
RH - reverse helical mixing paddle (each
occupying one 1-inch position)
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Table 1: Mixer Configuration (Per Sha, - FIG. 13
Longitudin RotationalLongitudina Rotational
al Pos'ttionElement Pos'ttionI PositionElement Position
1 FC 4 19 FP 3
2 FC 4 20 FC 3
3 FC 4 21 FC 3
4 FC 4 22 FC 3
5 FC 4 23 FC 3
6 FC 4 24 FP 3
7 FC 4 25 FP 3
8 FC 4 26 FP 3
9 FP 4 27 FP 1
10 FP 4 28 FP 1
11 FP 4 29 FP 1
12 FP 2 30 FP 3
FP 2 31 FP 3
13
14 FP 2 32 FP 3
2 0 15 FP 3 33 FP 4
16 FP 4 34 FP 1
17 FP 1 35 FP 2
18 FP 2 36 RH 1
The use of two or more feed zones and two or
more mixing zones in the mixer configuration 102, permits
sequential addition and mixing of different gum base
ingredients. For example, a high viscosity portion
including elastomer, filler, and some resin or polyvinyl
acetate can be continuously fed to the first feed zone
125 in FIG. 13. These ingredients can then be thoroughly
mixed in the first paddle mixing zone 130 before being
combined with additional ingredients. A lower viscosity
portion including waxes (when used), fats, oils,
colorants and additional resin or polyvinyl acetate can
be continuously fed to the second feed zone 135. All gum
base ingredients can then be thoroughly mixed in the
second paddle mixing zone 150.
~~~~~oo
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The.mixer configuration 102 shown in FIG. 13
. is, in practice, surrounded by one or more barrel seg-
ments extending the length of the mixer configuration
102. FIG. 14 illustrates, schematically, a typical
barrel 105 surrounding the mixer configuration 102. A
motor 101 drives the shafts 110 which support the mixer
elements. The gum base ingredients are fed through feed
ports 103 and 123 in the barrel 105. The gum base
remains in the mixer for a sufficient time to ensure
homogeneity, for example, a time on the order of about
20-30 minutes, and exits through an exit nozzle 155. The
barrel 105 may be heated or cooled. Heating may be
Wcco.:~plished using hot water or a steam jacket
surrounding the barrel (not shown). Cooling may be
accomplished by supplying cooling water to a jacket
surrounding the barrel 105. Alternative methods of
heating and cooling may also be employed. Generally,
heating is applied at the start up, but cooling is
applied in the latter stages to prevent overheating and
base degradation.
The heating and cooling of the barrel should be
supplied, as necessary, to maintain the product exit
. temperatures at about 90C-150C, preferably at about
100-135C, during mixing of the gum base ingredients.
FIG. 15 is a sectional view of the barrel 105
which indicates how the paddle mixer is able to operate
with longer residence times, compared to a conventional
twin screw extruder. As shown in FIG. 15, the barrel
wall 116 has the shape of two intersecting cylinders,
each cylinder having a diameter larger than the largest
diameter of the mixing paddle 85 contained therein. This
barrel configuration resembles that of a standard twin
screw extruder. However, unlike the screws of a twin
screw extruder, the paddles 85 do not mostly fill the
space defined by the barrel wall 116.
The mixing paddles 85 have a typically close
tolerance with the barrel wall 116, and with each other,
..
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in the vicinity of the lines 90 and 92 where the concave
surfaces intersect. For paddles 85 having a long
diameter of 4.874 inches, the closest tolerance between
each paddle and the barrel wall 116 may be on the order
of about 0.048 inch to about 0.078 inch, and the closest
tolerance between the two paddles may be on the order of
about 0.060 inch to about 0.090 inch. However, away from
the lines 90 and 92, the distance between each paddle 85~
and the barrel wall 116 is much greater. Due to the
unique design of the paddles 85, the percentage of barrel
space occupied by the paddles 85 is much smaller than for
a conventional twin screw extruder. Also, the pressure
in the paddle mixer should remain below about 50 psig,
preferably below about 20 psig, when there is a large
percentage of paddles compared to other elements. Each
paddle 85, when viewed from the front as in FIG. 15, has
a smaller width than height. Preferably, the ratio of
height to width of each mixing paddle is more than 1.5:1.
Most preferably, the ratio of height to width for each
mixing paddle is more than 2:1.
The large amount of available barrel space also
allows the method of the invention to be practiced at
high residence times in paddle mixers. The high
proportion of mixing paddles, especially flat paddles,
also contributes to the longer residence times and lower
pressure. The average residence time in the paddle mixer
should be at least about 10 minutes, preferably more than
15 minutes, most preferably more than 20 minutes.
The remaining operating parameters, e.g., mixer
rpm, feed rates, production rates, etc. vary depending on
the size of the mixer and on the specific gum base
composition. A commercially available paddle mixer
suitable for practicing the invention is a Teledyne
Readco Continuous Processor, available from Teledyne
Readco in York, Pennsylvania. These paddle mixers are
available in a wide variety of sizes. Paddle diameters
for the different size mixers range from 2 to 24 inches,
t
p~,~S95/03229
WO 96108161
- 35 -
and the ratios of mixer length to diameter (L/D) range
from 4:1 to 14:1. For purposes of the present invention,
the maximum paddle diameter is preferably between 2
inches and 5 inches, and the L/D is preferably about 7:1.
The paddle mixer configuration and process conditions
should be selected so that a homogeneous gum base product
is achieved.
In a particularly useful embodiment, two or
more paddle mixers may be used in series, in the manner
illustrated in FIG. 16. The use of two mixers in series
allows greater flexibility for feeding different gum base
ingredients at different locations. A combination of
elastomer, fiiier and resin can ire continuously fed via
feed port 103 to the feed barrel 105 of the first mixer.
15' These materials are mixed in the first mixer, after which
additional resin can be added to the first mixer via feed
port 123. The combined ingredients are blended in the
first mixer, and leave the first mixer at the exit 155,
whereupon they are immediately fed into the barrel 205 of
the second mixer 208 (powered by motor 201) via the feed
port 203. Polyvinyl acetate can also be continuously fed
to the barrel 205 from hopper 207, via feed conveyor 209
and feed port 203.
Further ingredients, such as waxes or oils, can
be injected into the second mixer from feed tanks 211 and
231, via pumps 213 and 233. Optionally, a portion of
ingredients can be added into a downstream feed port 204.
After all the components are mixed, the gum base leaves
the second mixer via exit 255. A wide variety of
different feeding and mixing arrangements can also be
employed using two or more paddle mixers in series, in
order to achieve good dispersion of ingredients and a
wide variety of gum base products.
In addition to the paddles described above, a
wide variety of mixing paddles, available from various
extruder companies, can be used. Paddles, often called
kneading elements, must have the effect of mixing in an
WO 96/08161 i, PC"T/US95/03229
- 36 -
extruder. Paddles can be two-sided, three-sided, or
multiple sided.
The paddle mixer, which may be referred to as a
compounder, has different characteristics than a typical
extruder even though the same equipment may be used. The
difference between an extruder and a compounder is the
ratio of paddles or kneading elements to the conveying
elements. Conveying elements and compression elements
cause an extruder to build up pressure. Paddles or
kneading elements do not build as much pressure in the
extruder, thus there is more mixing with low pressure.
If the extruder contains at least 40% kneading elements,
th~n the pressure can be about one-fifth to one-tenth
that of a typical extruder which uses more conveying and
compression elements.
Nearly all extruders can be used as
compounders. However, compounders which have a low L/D
ratio of about 3:1 to 20:1 cannot generally be used as
high pressure extruders. Also, compounders with this low
L/D ratio have less effective shaft length and may
require more paddle or kneading elements compared to
conveying elements. For this type of compounder, mixing
paddles should cover at least 50%, and preferably at
least 60% of the shaft. Conversely, for an extruder
having an L/D of about 20/1 to about 40/1, only about 40%
of the shaft needs to be covered with mixing paddles or
kneading elements. For extruders with high L/D ratios
greater than 40/1, only about 30% of the shaft may need
to be covered with mixing paddles or kneading elements.
One of the key advantages to the preferred
embodiment of the paddle mixer disclosed above is that
the residence time is much higher than in typical
extruders. Many extruders provide a residence time of
less than 2 minutes or even less than 1 minute. However,
in the preferred paddle mixer described above, a
residence time of at least 10 minutes, and preferably at
least 15-20 minutes, can be provided.
219 9 -6 p ~ ~C'!'/US 9 5 0 3 ~ ~ ~
:j ~A~US 12 APR 1996
- 37 -
C. Blade-and-Pin Mixers
The method of the present invention may also be
advantageously performed using a continuous mixer whose
mixing screw is composed primarily of precisely arranged
mixing elements with only a minor fraction of simple
conveying elements. A presently preferred mixer is a
blade-and-pin mixer exemplified in Fig. 17. This mixer
may be used to produce not only gum base, but an entire
chewing gum composition. A blade-and-pin mixer uses a
combination of selectively configured rotating mixer
blades and stationary barrel pins to provide efficient
mixing over a relatively short distance. A commercially
available blade-and-pin mixer is the Buss kneader,
manufactured by Buss AG in Switzerland, and available
from Buss America, located in Bloomingdale, Illinois.
Referring to FIG. 17, a presently preferred
blade-and-pin mixer 100 includes a single mixing screw
120 turning inside a barrel 140 which, during use, is
generally closed and completely surrounds the mixing
screw 120. The mixing screw 120 includes a generally
cylindrical shaft 122 and three rows of mixing blades 124
arranged at evenly spaced locations around the screw
shaft 122 (with only two of the rows being visible in
FIG. 1). The mixing blades 124 protrude radially outward
from the shaft 122, with each one resembling the blade of
an axe.
The mixing barrel 140 includes an inner barrel
housing 142 which is generally cylindrical when the
barrel 140 is closed around the screw 120 during
operation of the mixer 100. Three rows of stationary
pins 144 are arranged at evenly spaced locations around
the screw shaft 122, and protrude radially inward from
the barrel housing 142. The pins 144 are generally
cylindrical in shape, and may have rounded or bevelled
ends 146.
The mixing screw 120 with blades 124 rotates
inside the barrel 140 and is driven by a variable speed
bNlFt~flFi1 SHFFT
219960 , F3i:
WO 96/08161 PCT/US95/03229
- 38 -
motor (not shown). During rotation, the mixing screw 120
also moves back and forth in an axial direction, creating
a combination of rotational and axial mixing which is
highly efficient. During mixing, the mixing blades 124
continually pass between the stationary pins 144, yet the
blades and the pins never touch each other. Also, the
radial edges 126 of the blades 124 never touch the barrel
inner surface 142, and the ends 146 of the pins 144 never
touch the mixing screw shaft 122.
FIGS. 18-22 illustrate various screw elements
which can be used to configure the mixing screw 120 for
optimum use. Figs. 18a and 18b illustrate on-screw
elements 60 and 61 which are used in conjunction with a
restriction ring assembly. The on-screw elements 60 and
61 each include a cylindrical outer surface 62, a
plurality of blades 64 projecting outward from the
surface 62, and an inner opening 66 with a keyway 68 for
receiving and engaging a mixing screw shaft (not shown).
The second on-screw element 61 is about twice as long as
the first on-screw element 60.
FIG. 18c illustrates a restriction ring
assembly 70 used to build back pressure at selected
locations along the mixing screw 120. The restriction
ring assembly 70 includes two halves 77 and 79 mounted to
the barrel housing 142, which halves engage during use to
form a closed ring. The restriction ring assembly 70
includes a circular outer rim 72, an inner ring 74 angled
as shown, and an opening 76 in the inner ring which
receives, but does not touch, the on-screw elements 60
and 61 mounted to the screw shaft. Mounting openings 75
in the surface 72 of both halves of the restriction ring
assembly 70 are used to mount the halves to the barrel
housing 142.
FIG. 19 illustrates the relationship between
the restriction ring assembly 70 and the on-screw
elements 60 and 61 during operation. When the mixing
screw 120 is turning inside the barrel 140, and
''VO 96/08161 219 9 6 0 ~ ' ' p~~g95/03229
- 39 -
reciprocating axially, the clearances between the on-
screw elements 60 and 61 and the inner ring 74 provide
the primary means of passage of material from one side of
the restriction ring assembly 70 to the other. The on-
screw element 60 on the upstream side of the restriction
ring assembly includes a modified blade 67 permitting
clearance of the inner ring 74. The other on-screw
element 61 is placed generally downstream of the
restriction ring assembly 70, and has an end blade (not
visible) which moves close to and wipes the opposite
surface of the inner ring 74.
The clearances between outer surfaces 62 of the
on-screw elements 60 and 61 and the inner ring 74 of the
restriction ring assembly 70, which can vary and
preferably are on the order of 1-5 mm, determine to a
large extent how much pressure build-up will occur in the
upstream region of the restriction ring assembly 70
during operation of the mixer 100. It should be noted
that the upstream on-screw element 60 has an L/D of about
1/3, and the downstream on-screw element 61 has an L/D of
about 2/3, resulting in a total L/D of about 1.0 for the
on-screw elements. The restriction ring assembly 70 has
a smaller L/D of about 0.45 which coincides with the L/D
of the on-screw elements 60 and 61, which engage each
other but do not touch the restriction ring assembly.
Figs. 20 and 21 illustrate the mixing or
"kneading" elements which perform most of the mixing
work. The primary difference between the lower shear
mixing element 80 of FIG. 20 and the higher shear mixing
element 78 of FIG. 21 is the size of the mixing blades
which project outward on the mixing elements. In FIG.
21, the higher shear mixing blades 83 which project
outward from the surface 81 are larger and thicker than
the lower shear mixing blades 84 projecting outward from
the surface 82 in FIG. 20. For each of the mixing
elements 80 and 78, the mixing blades are arranged in
three circumferentially-spaced rows, as explained above
WO 96108161 PCT/US95103229
2~9960~ ~..~~:~
- 40 -
with respect to FIG. 17. The use of thicker mixing
blades 83 in FIG. 21 means that there is less axial
distance between the blades and also less clearance
between the blades 83 and the stationary pins 144 as the
screw 120 rotates and reciprocates axially (FIG. 17).
This reduction in clearance causes inherently higher
shear in the vicinity of the mixing elements 78. FIG. 22
illustrates a single stationary pin 144 detached from the
barrel 140. The pin 144 includes a threaded base 145
which permits attachment at selected locations along the
inner barrel shaft 142. It is also possible to configure
some of the pins 144 as liquid injection ports by
providing them with hollow center vg~ehings.
FIG. 23 is a schematic view showing the
presently preferred barrel configuration, including the
presently preferred arrangement of barrel pins 144. FIG.
24 is a corresponding schematic view illustrating the
presently preferred mixing screw configuration. The
mixer 200 whose preferred configuration is illustrated in
, FIGS. 23 and 24 has an overall active mixing L/D of about
19.
The mixer 200 includes an initial feed zone 210
and five mixing zones 220, 230, 240, 250 and 260. The
zones 210, 230, 240, 250 and 260 include five possible
large feed ports 212, 232, 242, 252 and 262,
respectively, which can be used to add major (e. g. solid)
ingredients to the mixer 200. The zones 240 and 260 are
also configured with five smaller liquid injection ports
241, 243, 261, 263 and 264 which are used to add liquid
ingredients. The liquid injection ports 241, 243, 261,
263 and 264 include special barrel pins 144 formed with
hollow centers, as explained above.
Referring to FIG. 23, barrel pins 144 are
preferably present in most or all of the available
locations, in all three rows as shown.
Referring to FIG. 24, the presently preferred
configuration of the mixing screw 120 for most chewing
.:
YO 96/08161 PCTIUS95/03229
- 41 -
gum products is schematically illustrated as follows.
Zone 210, which is the initial feed zone, is configured
with about 1-1/3 L/D of low shear elements, such as the
element 40 shown in FIG. 4. The L/D of the initial feed
zone 210 is not counted as part of the overall active
mixing L/D of 19, discussed above, because its purpose is
merely to convey ingredients into the mixing zones.
The first mixing zone 220 is configured, from
left to right (FIG. 24), with two low shear mixing
elements 80 (FIG. 20) followed by two high shear elements
78 (FIG. 21). The two low,shear mixing elements
contribute about 1-1/3 L/D of mixing, and the two high
shear mixing elcr~e~Ws contribute about 1-1/3 L/D of
mixing. Zone 220 has a total mixing L/D of about 3.0,
including the end part covered by a 57mm restriction ring
assembly 70 with cooperating on-screw elements 60 and 61
(not separately designated in FIG. 24).
The restriction ring assembly 70 with
cooperating on-screw elements 60 and 61, straddling the
end of the first mixing zone 220 and the start of the
second mixing zone 230, have a combined L/D of about 1.0,
part of which is in the second mixing zone 230. Then,
zone 230 is configured, from left to right, with three
low shear mixing elements 80 and 1.5 high shear mixing
elements 78. The three low shear mixing elements
contribute about 2.0 L/D of mixing, and the 1.5 high
shear mixing elements contribute about 1.0 L/D of mixing.
Zone 230 has a total mixing L/D of about 4Ø
Straddling the end of the second mixing zone
230 and the start of the third mixing zone 240 is a 60mm
restriction ring assembly 70 with cooperating on-screw
elements 60 and 61 having an L/D of about 1Ø Then,
zone 240 is configured, from left to right, with 4.5 high
shear mixing elements 78 contributing a mixing L/D of
about 3Ø Zone 240 also has a total mixing L/D of about
4Ø
WO 96/08161 ~ PCT/US95/03229
~~ -' 4 2 -
Straddling the end of the third mixing zone 240
and the start of the fourth mixing zone 250 is another
60mm restriction ring assembly 70 with cooperating on-
screw elements having an L/D of about 1Ø Then, the
remainder of the fourth mixing zone 250 and the fifth
mixing zone 260 are configured with eleven low shear
mixing elements 80 contributing a mixing L/D of about 7~/a.
Zone 250 has a total mixing L/D of about 4.0, and zone
260 has a total mixing L/D of about 4Ø
Examples 1-3 - Continuous Chewinct Gum Manufacture
When the chewing gum base is made in a blade-
a:.dmpir. ~ixe~, it has been found that it is possible to
complete the making of the chewing gum composition in the
same mixer. General procedures for making chewing gum
base according to the present invention, and then making
that gum base into chewing gum, are as follows. In order
to accomplish the total chewing gum manufacture using the
preferred blade-and-pin mixer 200 (Fig. 17), it is
advantageous to maintain the rpm of the mixing screw 120
at less than about 150, preferably less than about 100.
Also, the mixer temperature is preferably optimized so
that the gum base is at about 130F or lower when it
initially meets the other chewing gum ingredients, and
the chewing gum product is at about 130F or lower
(preferably 125F or lower) when it exits the mixer.
This temperature optimization can be accomplished, in
part, by selectively heating and/or water cooling the
barrel sections surrounding the mixing zones 220, 230,
240, 250 and 260 (Fig. 23).
In order to manufacture the gum base, the
following preferred procedure can be followed. The
elastomer, part of the filler, and at least some of the
elastomer solvent are added to the first large feed port
212 in the feed zone 210 of the mixer 200, and are
subjected to highly dispersive mixing in the first mixing
zone 220 while being conveyed in the direction of the
CVO 96/08161 PCT/US95/03229
- 43 -
arrow 122. The remaining filler, elastomer solvent (if
any) and polyvinyl acetate are added to the second large
feed port 232 in the second mixing zone 230, and the
ingredients are subjected to a more distributive mixing
in the remainder of the mixing zone 230.
Fats, oils, waxes (if used), emulsifiers and,
optionally, colors and antioxidants, are added to the
liquid injection ports 241 and 243 in the third mixing
zone 240, and the ingredients are subjected to
distributive mixing in the mixing zone 240 while being
conveyed in the direction of the arrow 122. At this
point, the gum base manufacture should be complete, and
the gum base should leave the third mixing zone 24~ as a
substantially homogeneous, lump-free compound with a
uniform color.
The fourth mixing zone 250 is used primarily to
cool the gum base, although minor ingredient addition may
be accomplished. Then, to manufacture the final chewing
gum product, glycerin, corn syrup, other bulk sugar
sweeteners, high intensity sweeteners, and flavors can be
added to the fifth mixing zone 260, and the ingredients
are subjected to distributive mixing. If the gum product
is to be sugarless, hydrogenated starch hydrolyzate or
sorbitol solution can be substituted for the corn syrup
and powdered alditols can be substituted for the sugars.
Preferably, glycerin is added to the first
liquid injection port 261 in the fifth mixing zone 260.
Solid ingredients (bulk sweeteners, encapsulated high
intensity sweeteners, etc.) are added to the large feed
port 262. Syrups (corn syrup, hydrogenated starch
hydrolyzate, sorbitol solution, etc.) are added to the
next liquid injection port 263, and flavors are added to
the final liquid injection port 264. Flavors can
alternatively be added at ports 261 and 263 in order to
help plasticize the gum base, thereby reducing the
temperature and torque on the screw. This may permit
running of the mixer at higher rpm and throughput.
2199~0~~
WO 96/08161 PCT/US95/03229
- 44 -
The gum ingredients are compounded to a
homogeneous mass which is discharged from the mixer as a
continuous stream or "rope". The continuous stream or
rope can be deposited onto a moving conveyor and carried
to a forming station, where the gum is shaped into the
desired form such as by pressing it into sheets, scoring,
and cutting into sticks. Because the entire gum
manufacturing process is integrated into a single
continuous mixer, there is less variation in the product,
and the product is cleaner and more stable due to its
simplified mechanical and thermal histories.
EXAMPLES 1-3
The following Examples 1-3 were run using a
Buss kneader with a 100mm mixer screw diameter,
configured in the preferred manner described above
(unless indicated otherwise), with five mixing zones, a
total mixing L/D of 19, and an initial conveying L/D of
1-1/3. The product mixture exited as a continuous rope.
Liquid ingredients were fed using volumetric
pumps into the large feed ports and/or smaller liquid
injection ports generally positioned as described above,
unless otherwise indicated. The pumps were appropriately
sized and adjusted to achieve the desired feed rates.
Dry ingredients were added using gravimetric
screw feeders into the large addition ports positioned as
described above. Again, the feeders were appropriately
sized and adjusted to achieve the desired feed rates.
Temperature control was accomplished by
circulating fluids through jackets surrounding each
mixing barrel zone and inside the mixing screw. Water
cooling was used where temperatures did not exceed 200F,
and oil cooling was used at higher temperatures. Where
water cooling was desired, tap water (typically at about
57F) was used without additional chilling.
Temperatures were recorded for both the fluid
and the ingredient mixture. Fluid temperatures were set
VO 96/08161 PC"T/US95/03229
- 45 -
for each barrel mixing zone (corresponding to zones 220,
230, 240, 250 and 260 in Figs. 23 and 24), and are
reported below as Z1, Z2, Z3, Z4 and Z5, respectively.
Fluid temperatures were also set for the mixing screw
120, and are reported below as S1.
Actual mixture temperatures were recorded near
the downstream end of mixing zones 220, 230, 240 and 250;
near the middle of mixing zone 260; and near the end of
mixing zone 260. These mixture temperatures are reported
below as T1, T2, T3, T4, T5 and T6, respectively. Actual
mixture temperatures are influenced by the temperatures
of the circulating fluid, the heat exchange properties of
the mixture and surrounding barrel, and the mechanical
heating from the mixing process, and often differ from
the set temperatures due to the additional factors.
All ingredients were added to the continuous
mixer at ambient temperature (about 77°F) unless
otherwise noted.
EXAMPLE 1
25/75% Split of Filler
This example illustrates the preparation of a
gum base to be used to make a peppermint flavored sugar
chewing gum. A blend of 40.854% dusted ground
isobutylene-isoprene copolymer, 21.176% low molecular
weight terpene resin, 21.358% high molecular weight
terpene resin, and 16.612% fine ground calcium carbonate
was added to the first large feed port 212 at 21.3 lb/hr.
A blend of 6.172% high molecular weight
polyvinyl acetate, 49.363% low molecular weight polyvinyl
acetate, 5.790% high molecular weight terpene resin,
5.790% low molecular weight terpene resin, 31.496% fine
ground calcium carbonate and 1.390% color was added at
20.6 lb/hr. into the second large feed port 232.
Polyisobutylene (preheated to 250°F) was also added into
the second large feed port at 3.5 lb/hr.
WO 96/08161 219 9 6 D ~ , 9 ; ; ;. ', p~'/US95/03229
- 46 -
A fat mixture (225°F) was injected into zone
240 at a total rate of 14.16 lb/hr. This fat mixture
included 37% hydrogenated cottonseed oil, 22%
hydrogenated soybean oil, 15% partially hydrogenated
cottonseed oil, 23% glycerol monostearate, 2.4% soy
lecithin and 0.12% BHT.
Glycerin was injected into zone 260 at 3.87
lb/hr. A mixture of 85% sucrose and 15% dextrose
monohydrate was added into the large feed port 262 at
203.1 lb/hr. Corn syrup (100°F) was injected into zone
260 at 30.0 lb/hr. A peppermint flavor was injected into
zone 260 at 3.0 lb/hr.
The zone temperatures (Z1-Z5, °F) were set at
350, 350, 100, 55 and 55, respectively, and the screw
temperature (S1) was set at 100°F. The mixture
temperatures (T1-T6, °F) were measured as 322, 289, 161,
118, 109 and 89, respectively. The screw rotation was
set at 60 rpm.
The product exited the mixer at 122°F.
EXAMPLE 2
50,/50% Split of Filler
This example illustrates the preparation of a
gum base to be used to make a peppermint flavored sugar
chewing gum. A blend of 35.089% dusted ground
isobutylene-isoprene copolymer, 18.188% low molecular
weight terpene resin, 18.344% high molecular-weight
terpene resin, and 28.379% fine ground calcium carbonate
was added to the first large feed port 212 at 18.8 lb/hr.
A blend of 6.899% high molecular weight
polyvinyl acetate, 55.177% low molecular weight polyvinyl
acetate, 6.472% high molecular weight terpene resin,
6.472% low molecular weight terpene resin, 23.427% fine
ground calcium carbonate and 1.553% color was added at
22.24 lb/hr. into the second large feed port 232.
Polyisobutylene (preheated at 250°F) was also added into
the second large feed port at 23.0 lb/hr.
VO 96/08161 PCT/US95/03229
- 47 -
A fat mixture (225°F) was injected into zone
240 at a total rate of 14.16 lb./hr. This fat mixture
included 37% hydrogenated cottonseed oil, 22%
hydrogenated soybean oil, 15% partially hydrogenated
cottonseed oil, 23% glycerol monostearate, 2.4% soy
lecithin and 0.12% BHT.
Glycerin was injected into zone 260 at 3.87
lb/hr. A mixture of 85% sucrose and 15% dextrose
monohydrate was added into the large feed port 262 at
203.1 lb/hr. Corn syrup (100°F) was injected into zone
260 at 30.0 lb/hr. A peppermint flavor was injected into
zone 260 at 3.0 lb/hr.
The zone tciiyeratures (Z3-Z5, °Fj were set at
350, 350, 100, 55, and 55, respectively, and the screw
temperature (S1) was set at 100°F. The mixture
temperatures (T1-T6, °F) were measured as 323, 290, 162,
115, 107 and 89, respectively. The screw rotation was
set at 60 rpm.
The product exited the mixer at 122°F.
EXAMPLE 3
75j25% Split of Filler
This example illustrates the preparation of a
gum base to be used to make a peppermint flavored sugar
chewing gum. A blend of 30.708% dusted ground
isobutylene-isoprene copolymer, 15.917% low molecular
weight terpene resin, 16.054% high molecular weight
terpene resin, and 37.322% fine ground calcium carbonate
was added to the first large feed port 212 at 16.3 lb/hr.
A blend of 7.808% high molecular weight
polyvinyl acetate, 62.452% low molecular weight polyvinyl
acetate, 7.325% high molecular weight terpene resin,
7.325% low molecular weight terpene resin, 13.331% fine
ground calcium carbonate and 1.758% color was added at
22.24 lb/hr. into the second large feed port 232.
Polyisobutylene (preheated to 250°F) was also added into
the second large feed port at 26.1 lb/hr.
WO 96/08161 ; PCTIUS95103229
~~~9so~ ,._ :a
- 48 -
A fat mixture (225°F) was injected into zone
240 at a total rate of 14.16 lb/hr. This fat mixture
included 37% hydrogenated cottonseed oil, 22%
hydrogenated soybean oil, 15% partially hydrogenated
cottonseed oil, 23% glycerol monostearate, 2.4% soy
lecithin and 0.12% BHT.
Glycerin was injected into zone 260 at 3.87
lb/hr. A mixture of 85% sucrose and 15% dextrose
monohydrate was added into the large feed port 262 at
203.1 lb/hr. Corn syrup (100°F) was injected into zone
260 at 30.0 lb/hr. A peppermint flavor was injected at
zone 260 at 3.0 lb/hr.
The zone temperature (Z1-Z5, °F) were set at
350, 350, 100, 55 and 55, respectively, and the screw
temperature (S1) was set at 100°F. The mixture
temperatures (T1-T6, °F) were measured at 322, 286, 161,
116, 107 and 88, respectively. The screw rotation was
set at 60 rpm.
The product exited the mixer at 124°F.
COMPARATIVE EXAMPLE
100% of Filler to Port 232
This comparative example illustrates the
preparation of a gum base to be used to make a peppermint
flavored sugar chewing gum. A blend of 48.993% dusted
ground isobutylene-isoprene copolymer, 25.394% low
molecular weight terpene resin and 25.613% high molecular
weight terpene resin was added to the first large feed
port 212 at 24.4 lb/hr.
A blend of 5.588% high molecular weight
polyvinyl acetate, 44.690% low molecular weight polyvinyl
acetate, 5.242% high molecular weight terpene resin,
5.242% low molecular weight terpene resin, 37.981% fine
ground calcium carbonate and 1.258% color was added at
22.24 lb/hr. into the second large feed port 232.
Polyisobutylene (preheated to 250°F) was also added into
the second large feed port at 17.7 lb/hr.
219~~~~
PCT/US95/03229
~'O 96/08161
- 49 -
A fat mixture (225F) was injected into zone
240 at a total rate of 14.16 lb/hr. This fat mixture
included 37% hydrogenated cottonseed oil, 22%
hydrogenated soybean oil, 15% partially hydrogenated
cottonseed oil, 23% glycerol monostearate, 2.4% soy lecithin
and 0.12% BHT.
Glycerin was injected into zone 260 at 3.87 lb/hr.
A mixture of 85% sucrose and 15% dextrose monohydrate was
added to zone 260 at 203.1 lb/hr. Corn syrup (100F) was
injected into zone 260 at 30.0 lb/hr. A peppermint flavor
was injected into zone 260 at 3.0 lb /hr.
The zone temperatures (Z1-Z5, F) were set at 350,
350, 100, 55 and 55, respectively, and the screw temperature
(S1) was set at 100F. The mixture temperatures (T1-T6, F)
were measured as 333, 292, 162, 118, 110 and 90,
respectively. The screw rotation was set at 60 rpm.
The product exited the mixer at 121F.
It should be appreciated that the methods of the
present invention are capable of being incorporated in the
form of a variety of embodiments, only a few of which have
been illustrated and described above. The invention may be
embodied in other forms without departing from its spirit or
essential characteristics. It will be appreciated that the
addition of some other ingredients, process steps, materials
or components not specifically included will have an adverse
impact on the present invention. The best mode of the
invention may therefore exclude ingredients, process steps,
materials or components other than those listed above for
inclusion or use in the invention. However, the described
embodiments are to be considered in all respects only as
illustrative and not restrictive, and the scope of the
invention is, therefore, indicated by the appended claims
rather than by the foregoing description. All changes which
come within the meaning and range of equivalency of the
claims are to be embraced within their scope.
