Note: Descriptions are shown in the official language in which they were submitted.
1118629
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l BAC~;GROUND OF THE I~VE~l:rION
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'I 1. Field of the rnvention
The present invention relates to a two-stage process for the
preparation of a chewing gum base utilizing solid elastomer.
2. Description of the Frior Art
S In United States Patent ~o, 3,995,064, there is described a
three-step ~rocess for the preparation of a chewing gum base
utllizing solid elastomer In which the order of mixing and
blending ingredients is stated to be critical, particularly with
¦ respect to tke oleaginous plasticizer and the hydrophobic
¦ plasticizer ingredients ~hi'ch cannot be added during mixing under
¦ high shear conditions~ In the process of aforementioned United
¦ States Patent No. 3,995,064, the hydrophobic plasticizer is added
¦ durins the second step where mixing ts conducted under reduced
shear conditions'and increased folding actionj and the oleaginous
plasticizer must be added in the third step wherein mixing is
conducted under rapid folding action with substantially no
shearing,
According to the two-stage process of the subject invention,
it has been found that all gum base ingredients may be subjected
to high intensity mixing under conditions of high shear.
Moreover, the oleaginous plasticizer ~s a necessary ingredient
, of the first stage wherein both the elastomer and the elastomer
solvent are present.
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il~8629
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DESCRIPTION O~ ~EE PAR~CULAR E~BODI~NTS
According to the present Invention, chewing gum base may be
prepared in a two-stage process ~herein, in the first stagelsolid
¦ elastomer is initially subjected to high intensity mixing under
¦ high shear conditions to mastlcate the solid elastomer and
obtain a substantially uniform, lump-free mass. An elastomer
solvent is then added, step-~ise, to the mixer containing the
masticated solid elastomer, followed by the step-wise addition
of an oleaginous plasticizer. Typlcally, these last named
ingredients are metered into the mixer containlng the masticated
solid elastomer.. The hlgh intensity mixing is conducted during
the step-wise addition of both the elastomer solvent and the
oleaginous plasticizer and continued after the addition of these
ingredients has been completed until a substantially molten,
uniform mass ls obtained. The effluent from the high intensity
mixer of stage one is a rubber compound, completely homogenous,
which has no undispersed eIastomeric particles and which can be
l stretched into a translucent fllm.
Solid elastomers sultakle for use in the process of this
invention are those ncrmally used tn che~ing gum base and
11186Z~
include synthetic gums or elastomers such as butadiene-styrene
copolymer, polyisobutylene and isobutylene-isoprene copolymer;
natural gums or elastomers such as chicle, natural rubber, jelutong,
balata, guttapercha, lechi caspi, sorva, or mixtures thereof.
Among these, butadiene-styrene copolymer, polyisobutylene,
isobutylene-isoprene copolymer or mixtures thereof are preferred
as the elastomer solid.
As the elastomer solvent, there may be mentioned terpene
resins such as polymers of ~-pinene or ~-pinene; rosin derivatives
such as the glycerol ester of polymerized rosin or the glycerol
ester of hydrogenated rosin; and mixtures thereof.
The following oleaginous plastici~ers are suitable for use
in the practice of this invention: hydrogenated vegetable oils,
cocoa butter, natural waxes, petroleum waxes such as the
polyethylene waxes, and paraffin waxes; or mixtures thereof.
The first stage of the process of the present invention may
be conducted without the addition of heat since heat is generated
by the high intensity mixing of the solid elastomer. However, it
has been found advantageous to apply heat to the mixing kettle
initially ~by heating the mixing kettle to a temperature range
of 88C. - 102C) to speed up the process. After the solid
elastomer has been mixed for a period of time, heat is built up
by the shearing of the elastomer so that the application of heat
is no longer necessary and may be discontinued. Cooling is some-
times necessary i.f too much heat is built up during the shearing
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of the elastomer. If cooling is applied, it may then be necessary to apply
additional heat to prevent the mass from adhering to the mixer. In any
event, maximum temperatures built up duTing the mixing should not exceed the
decomposition temperatures of the ingredients being mixed during a particular
stage of proccssing. The mixing of the stage one ingredients is completed
when a substantially molten, uniform mass is ohtained.
lhe sequence of addition of the named ingredients and the high
intensity mixing are critical in this first stage.
The second stage in the process of the present invention involves
the step-wise addition of the remaining chewing gum base ingredients and ad-
ditional high intensity mixing under high shear conditions ulltil a uniform
blend of ingredients is obtained. The second stage ingredients includes a
hydrophobic plasticizer, additional oleaginous plasticizer, a non-toxic
vinyl polymer, and an emulsifier. If the process is being performed in a
continuous manner, the second step ingredients are added to the molten nass
of stage one, step-wise, with continuous high intensity mixing. Typically,
the stage two ingredients are metered into the molten mass of stage one~ in
sequence by decreasing order of viscosity. For example, the hydrophobic
plasticizer is added first, followed by the oleaginous plasticizer, the vinyl
polymer, and lastly, the emulsifier.
Suitable non-toxic vinyl polymers are those conventionally used in
chewing gum base such as polyvinyl acetate or partially hydrolyzed polyvinyl
acetate, i.e., polyvinyl alcohol, and mixtures thereof.
As the hydrophobic plasticizer, there may be mentioned alcohol
esters of rosin, for example, glycerol esters of hydrogenated rosin, the
glycerol esters of partially hydrogenated rosin or mixtures thereof.
Oleaginous plasticizers mentioned above which are suitable for
addition during stage one are also suitable for addition during stage two.
As the emulsifier, lecithin, fatty acid monoglycerides, diclycer-
ides or triglycerides, i.e., glycerol monostearate or propylene glycol mono-
11186;~9
stearate~ and mixtures thereof, are suitable for use in the process of thisinvention.
As has been mentioned, high intensity mixing under conditions of
high shear is continued throughout the addition of all stage two ingredients.
When the process of the invention is performed in a continuous manner, suf-
ficient heat is applied during stage two to maintain the mass in a molten
condition while the ingredients are added.
In the event of batch processing, heat is-also applied initially
to ensure that the stage one mass is molten before commencement of high
intensity mixing and during the addition of the stage two ingredients. In
a batch process, the stage one molten mass may be fed into a holding tank,
from which a predetermined amount of the molten mass (heated if necessary)
is metered into a second high intensity mixer. The stage two ingredients
are then added, typically by metering, with continuous high intensity mix-
ing. After all of the stage two ingredients have been added, ~he high
intensity mixing is continued until a uniform blend of all ingredients is
obtained.
In an alternative process for preparing the chewing gum base of
this invention, certain of the stage two ingredients may be added during
stage one. Specifically, the hydrophobic plasticizer (except as specified
below) may be added during the stage one processing. Since the above named
ingredients for the elastomer solvent and the hydrophobic plasticizer are
similar, they may be used interchangeably. The hydrophobic plasticizer may
be added during stage one after the addition of the elastomer and the elas-
tomer solvent. In another variation of the process of the invention, the
emulsifier is added during stage one processing or partially during both
stage one and stage two processing. The emulsifier may be added before or
after the addition of the oleaginous plasticizer. In any event, as has been
specified above, each ingredient is added step-wise, typically by metering,
with continuous high intensity mixing.
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For the preparation of certain types of gum base, the non-toxic
vinyl polymer normally added during stage two processing may be omitted.
In such case, a portion of the hydrophobic plasticizer must be added during
the stage two processing.
The addition of optional ingredients such as antioxidants, pres-
ervatives, fillers and pigments is also contemplated in the process of this
inven~ion. Antioxidants, preservatives and fillers may be added either dur-
ing stage one or stage two processing; pigments are added during stage two
processing. Typically, the antioxidants and preservatives (i.e., butylated
hydroxyanisole, butylated hydroxytoluene, propyl gallate and the like) are
pre-blended with one of the necessary ingredients prior to the step-wise
addition. In a preferred embodiment of this invention, antioxidants and/or
preservatives are preblended with the emulsifier and/or the oleaginous
plasticizer.
Fillers, including calcium carbonate, magnesium carbonate, talc
and the like may be added during stage one or stage two. Preferably, the
filler is added during stage two, typically as the first stage two ingredi-
ent.
Pigments (i.e., titanium dioxide, copper chlorophyllin, ~-carotene,
Red no. 3, Blue no. 2 and Yellow no. 6) if included are added during the
stage two processing, typically with the filler ingredient.
The above mentioned optional ingredients are added step-wise, with
continuous high intensity mixing as prèviously described for the necessary
gum base ingredients.
The various ingredients named above for use in the gum base pre-
pared according to the process of this invention are those conventionally
used in the preparation of chewing gum base. They may be present in the
following parts by weight, based on the total weight of the chewing gum
base composition:
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INGREDIENT PARTS BY WEI~11
Elastomer 5-15
Elastomer Solvent 5-25
Oleaginous Plasticizer 10-30
Non-toxic Vinyl Polymer 1-35
Hydrophobic Plasticizer 5-25
Emulsifier 2-10
Filler ~where used) 1-35
Antioxidant/preservatives 0-2
Pigments 0-2
The oleaginous plasticizer, which comprises from about 10% to
about 30% of the total gum base composition, is a necessary ingredient in
both stage one and stage two of the process of this invention. Generally,
from about 5 to about 15 parts by weight of the ol&aginous plasticizer are
added during stage one processing and from about 5 to about 15 parts by
weight are added during stage two processing.
: The foregoing sequence of addition of ingredients, with continuous
mixing has been found to be critical to the process of this invention. In
contrast to prior art processes, it has been found that the oleaginous plas-
ticizer must be added with the elastomer and elastomer solvent during
stage one and subjected to high intensity mixing if a completely homogenous
blend of ingredients is to be obtained. Furthermore, as opposed to the prior
art processes, it has been found that all remaining gum base ingredients may
be added in the second stage of the process and subjected to high intensity
mixing to obtain a uniform, substantially lump-free chewing gum base. The
two-stage process of the invention is flexible in that it may be performed
in a batch or continuous manner. Additionally, the process effectively re-
duces the time presently required to produce chewing gum base by convention-
al means using elastomer latex rather than solid elastomer.
The high intensity mixing apparatus suitable for use in the process
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of this invention provides a high degree of shear on the substances beingmixed such that milling action is achieved due to the close tolerances be-
tween moving surfaces. The mixers, feeding equipment, blenders and holding
tanks used in the process of this invention are conventional in design.
They may be jacketed, in a conventional manner, in order that heating or
cooling can be applied, when necessary, to maintain the ingredients in the
molten state and ensure efficient mixing.
In order to further illustrate the process of this invention, the
following examl~les are provided:
EXAMPLE 1
INGREDIENTS PART EIGHT
1. Butadiene-styrene copolymer latex solid 10
2. Glycerol ester of hydrogenated rosin 18
3. Hydrogenated vegetable oil 11
4 Calcium carbonate 15
5. Paraffin wax 10
6. Polyvinyl acetate 31
7. Glycerol monostearate 5
Preheat the high intensity mixer to 88C - 102C, add ingredient
1 and commence mixing. Continue to mix for about 20 minutes or until a
lump-free mass is obtained. Discontiuue heat and add ingredient 2, step-
wise, and continue mixing for a period of from 1 1/2 to 2 hours. Add 3,
step-wise, and continue mixing for from 1/2 to 3/4 of an hour. Discontinue
mixing and transfer the mass to a second high intensity mixer which is
jacketed to maintain a temperature of at least 85C but no higher than
105C. Commence mixing, add ingredient 4, step-wise, and continue mixing
for approximately 20 minutes. Add ingredients 5, 6 and 7, step-wise, mixing
each for at least 15 minutes before the next ingredient addition. When all
ingredients have been added, an additional 15 minutes of mixing is sufficient
to obtain a homogenous gum base.
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EXAMPLF. 2
INGREDIENTS PARTS BY WEIG~IT
1. Polyisobutylene solid 11
2. Dimerized rosin ester lO
3. Paraffin wax 13
4. Glycerol 0ster of 20
hydrogenated rosin
S. Hydrogenated vegetable oil 12
6. Polyvinyl acetate 25
7. Glycerol monostearate 9
Follow the procedure of Example 1 for ingredients 1, 2, and 3
and transfer the mass to a second high intensity mixer which is jacketed to
maintain a temperature of at least 85C but no higher than 105C. CGmmence
mixing and add ingredients 4, 5, 6 and 7, step-wise, mixing each for at
least 15 minutes before the next ingredient addition. When all ingredients
have been added, an additional 15 minutes of mixing is sufficient to obtain
a homogenous gum base.
EXAMPLE 3
INGREDIENTS PARTS BY WEIGHT
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1. Butadiene-styrene copolymer latex solid 10
2. Dimerized rosin 8
3. Glycerol esters of hydrogenated rosin 6
4. Lecithin
5. Hydrogenated vegetable oil 11
6. Calcium carbonate 15
7. Candelilla wax 9
8. Polyvinyl acetate 35
9. Glycerol monostearate 5
Follow the procedure of Example 1 for ingredients 1, 2 and 3 and
add ingredient 4, step-wise, and mix for about 15 minutes; then add ingredi-
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ent 5 and mix for from 1/2 to 3/4 of an hour. Transfer the mass to a sec-
ond higll intensity mixer, jacketed to maintain a temperature of at least
85C but no higher than 105C. Commence mixing and add ingredient 6, step-
wiseJ and continue mixillg for approximately 20 minutes. Add ingredients 7,
8 and 9, step-wise, mixing eacll at least 15 minutes before the next ingredi-
ent addition. When all ingredients have been added, an additional 15 min-
utes of mixing is sufficient to obtain a homogenous gum base.
EXAMPLE 4
INGREDIENTS PARTS BY WEIGIIT
1. Butadiene-styrene copolymer latex solid 12
2. Glycerol ester of hydrogenated rosin 18
3. Paraffin wax 5
4. Calcium carbonate 25
5. Dimerized rosin ester 30
6. Hydrogenated vegeta~le oil 5
7. Glycerol monostearate 4.92
8. Butylated hydroxy anisole, preblended with .08
a portion of No. 7
Follow the procedure of Example 1 for ingredients 1-4. Add in-
gredient 5, step-wise, and mix for approximately 30 minutes. Then add in-
gredients 6, 7 and 8, step-wise, mixing each for at least 15 minutes before
the next jngredient addition. When all ingredients have been added, an ad-
ditional 15 minutes of mixing is sufficient to obtain a homogenous gum base.
EXAMPLE 5
INGREDIENTS PARTS BY WEIGHT
1. Butadiene-styrene copolymer latex solid 11
2. Dimerized rosin 10
3. Lecithin 3
4. Paraffin wax 10
5. Calcium carbonate 21
6. Glycerol ester of hydrogenated rosin 10
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EXAMPLE 5 CO~T'D
INGREDIENTS PARTS BY WEIGHl'
. _ .
7. Hydrogenated vegetable oil 10
8. Polyvinyl alcohol 20
9. Glycerol monostearate 5
Follow the procedure of Example 1 for ingredients 1 and 2 and add
ingredient 3, step-wise, and mix for about 15 minutes; then add ingredient
4 and mix for from 1/2 to 3/4 of an hour. Transfer the mass to a second
high intensity mixer, jacketed to maintain a temperature of at least 85C,
but no higher than 105C. Commence mixing and add ingredient 5, step-wise,
and continue mixing for approximately 20 minutes. Add ingredients 6, 7, 8
and 9, step-wise mixing each at least 15 minutes before the next ingredient
addition. When all ingredients have been added, an additional 15 minutes of
mixing is sufficient to obtain a homogenous gum base.
