Note: Descriptions are shown in the official language in which they were submitted.
203~3111 ~
CONTINUOUS PROCESS FOR PREPARING
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LOW DENSITY BAR SOAP
FIELD OF THE INVENTION
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The invention relates to a continuous process for
preparing low density bar soap with a specific gravity that
can be controlled between 0.5 and 0.9. The invention is
especially directed to a process for economically making a
white soap of toilet har quality, without the use of
opacifiers, whiteners or brighteners; for increasing the
volume of the said soap bar; and for increasing the allow-
able water content in the finished soap bar.
BACKGROUND OF THE INVENTION
_ _ _ _ ._
Various processes for preparing aerated soap bars
by incorporation of air into the soap composition ha~e been
known for some time. These methods ~ary from simple mechan-
ical agitation of the soap in the cru~cher, to proc~sses
that require special eguipment and in some cases special
formulations to produce a commerrially acceptable product.
Typical prior art methods include:
l. Air is whipped into the molten soap while in
the crutcher, for example by rever-~ing the rotation of the
central stirri~g mechanism.
2. Incorporation of air into partially dried soap
chips at 115F by means of a modified soap plodder, dis-
closed in U~S. Patent 2,525~081 to Schulerud.
. 3. Mazzoni 'Float-o-matic' plodder. Commercially
available.
4. Aeration by introducing gas and mixing by
passage between two mutually displaceable surfaces, dis-
closed in European Patent 9064~.
I ~3731~
S. Molten soap processed through heat exchanger,
flash chamber, continuous crutcher with addition of air,
then cooling/mixing de~ice, disclosed in U.S. Patent
2,295,594 to Mills.
Methods 1, 2, 3 and 4 do not produce a bar that
has the uniformity of color, appearance or density required. I
Methods 3, 4 and 5 require spec~al equipment.
Other processes are disclosed in U.S. Patent
1,780,330 to Blair; 2,210,924 to Hood 2,398,776 to
Bodman; 2,494,891 to Marshall; 4,311,604 to Hornig; and
4,680,132 to Clark et al~
SUMMARY OF THE INVENTION
It is an object of the process of the present
invention to aerate bar soap in order to reduce bar density,
for increased volume, and for floatability of the soap bar.
It is also an object of the process of the present
invention ~o increase the allowable water content in bar
soap.
Thirdly, it i8 an object of the invention to
produce a commercially acceptable white soap bar by incorpo-
ration of air in a finely divided and uniformly distributed
form into the 80ap composition ir~ order to increase the
light scattering effect of the composition.
Fourthly, it is a~ object of thP invention to
produce soap bars with superior performance attributes
compared to commercially available soap bars of sLmilar
~om~osition, by means of an economical con~inuous process
that simpli~ies the usual 50ap processing procedure.
Also, it is an object of the process of the
inve~tion to insorporate air into the soap composition in a
finely controllable manner, so that density o~ the bar is
eproducible betweeD 0.5 and 0 9 specific gravity, and J0
~ ~373~
that the soap bar has consistent texture and color.
The process has several advantages over the prior
art.
The process provides for the density of the bar of
soap to be easily controllable, providing for soap densities
of between 0.5 and 0.9 with high reproducibility.
The process improves homogeneity of the bar
composition so that the soap texture is uniform. The
process allows for air cell5 to be finely dispersed through- ¦
out the soap composition ~hus resulting in a soap with
superior use characteristics and improved whiteness. Neat
soap with usual water composition of between 28~ and 35~ can
be continuously aerated by the present process so tha~ the
finished soap bar contains water content in the same range.
The process shortens or eliminates the drying and plodding
stages of soap processing, thus simplifying the soap making
process for resulting lower energy consumption than is usual
in the manufacture of soap. The process also allows for
increased flexibility in utilization of soap making facil-
ities.
DESCRIPTION OF TH~ DRAWINGS
. .
Figures 1 and 2 are diagrams showing the steps of
two variations of the process.
DESCRIPTION OF T~E INVENTION
The first process of the invention is describPd
with reference to Figure 1~ In the first step of ~he
process sodium soap in the neat phase, of toilet soap
quality, i~ prepared according to usual soapmaki~g proce-
dures by the kettle method or by a continuou~ process, so
the the neat soap has a composition of 10 to 50% coconut
oil and 90 to 50~ tallow, with a moisture content of between
28% and 35%.
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l - - 2~373~ ~
Preservatives and/or chelating agents, including
but not limited to tetrasodium ethylenediamine tetraacetic
acid, and etidronic acid, are mix~d into the molten nea~
soap in a crutcher maintained at a temperature of 180~ to
220F.
The molten soap mass is pumped into a water
jacketed melt mixer, and cooled to a temperature above the
melting point of the mixture. Antioxidants including but
not limited to ditertiary butyl paracresol, are dissolved in
the fragrance and added to the molten neat soap as it is
pumped into the hopper of the Goodway aeration unit. The
neat soap at this point contains preferably 30% moisture.
The mixer is operated continuously and air at a
pressure of 90 lbs per square inch is incorporated into the
soap mass with high shear mixing. The aerated soap is cast
into soapmaking ~rames in known manner according to the rt.
The cooled soap is then cut and stamped with the
desired logo, and conveyed to a packaging machine ~not
shown).
The second process of the invention is described
in reference to Figure 2.
Preservatives and/or chelating agents are mixed
into the molten neat soap in a crutcher maintained at a
temperature of 180F to 220F.
Antioxidants are dissolved in the fragrance and
added inline to the molten neat soap as it is pumped into
the hopper of a Goodway aeration unit.
The mixer is operated continuously and air at a
pressure of 90 lbs per square inch is incorporated into the
soap mass with high shear mixing. The hot aerated soap is
then filled directly into soap molds, tray containers or
other packaging. After the soap is cooled, the packaging is
~ ~037~a
sealed and labelled.
When the process of ~he present invention is
followed, the density of the product can be controlled by
adjusting the air flow rate, the mixer head speed and the
pump speed of the Goodway mixer. Bar soap of up to 30%
moisture is obtained compared to moisture content of 10 to
15% for regular toilet soaps~
Whiteners, brighteners or opacifiers such as
titanium dioxide, which are no~mally added to improve the
whiteness of toilet soap, are not required in the formu-
lation, since the finely dispersed air cells within the
solid soap cause a light scattering effect which increases
the R-value (whiteness value) of the soap.
It is discernable both visually and by MacBeth
colorimeter readings that the whitenes~ of the aerated soap
bar is equivalent or greater than nonaerated toilet soap
bars of comparable composition containing 0.5% titanium
dioxide. ~R-v~lue 84.5 for aerated soap versus 79.2 for
nonaerated soap with 0.5% titanium dioxide content.)
Due to the nature of the high shear mixing in
combinatio~ with dispersion of air cells in a finely divided
form throughout the soap mass, the homogeneity of the
product is greatly improved, resulting in a bar with commer-
cially acceptable appearance in regard to color and surface
texture.
It is obvious that the process of the present
invention uses less energy ~han conventional bar soap under
current manufacturing processes, and also allows for re-
duction in formulation costs.
The process of the presen~ invention is also
advantageous in that it elLminates the plodder and drier
stages normally used for soap bar manufacture.
Il I
~ - 2~
The Goodway mixer is a commercially available
mixer manufactured and sold by Goodway Industries, Inc. of
Bohemia, N.Y~
The invention is illustrated by the followiny
specific but non-limiting examples. .
Example 1
A total of 30 lbs of neat soap with composition
85% tallow and 15% coconut oil, with 31.5% moisture content
was prepared, and the molten soap was moved continuously to
the Goodway mixer, where air was incorporated into the soap
with high shear mixing. The hot aerated soap was formed
into blocks and cooled, bars cut and wrapped.
Exam ~
A total of 30 lbs of neat soap consist~n~ of a
sodium soap containing 70% tallow and 30% coconut oil, with
30~ moisture content was prepared. A sufficient quantity of
preservative was added to the molten soap. Soap fragrance
was addea at 1% to 1.4~ and the soap was immedia$ely moved
to the Goodway mixer where aix was incorporated into the
molten soap with high shear mixing. The aerated soap moved
continuously out of the mi~er and was c~st and allowed to
cool. The cooled soap wa~ cut into bars and wrapped.
Example 3
A total of 30 lbs of neat soap with composi~ion
85% tallow and 15~ coconut oil, with 30% moisture content
was prepared and the molten soap was aerated as in Examples
1 and 2. The hot aerated soap was filled directly into
transparent packaging trays with debossed logo, cooled and
sealed.
Bar soap produced according to the above described
proc~sses was of toilet ~oap quality and ~he density was
less t n that of water (i.e. the coap floated). The soap
373:L~
bar was very white and the volume was approximately 40%
greater than for a regular soap bar of the same weight.
Performance of the soap bars thus obtained was
superior to toilet and laundry bar soaps of similar composi-
tion, in regard to improved durability of the bar, rate of
useup of the soap bar during use, improved maintainance of
shape and texture over repeated use, and latherability.
Although the present invention has been described
with respect to particular embodiments in the example
thereof it will be understood by those skilled in the art
that other variations and modifications of the invention can
be made without departing from the essence and scope there-
of, only such limitations should be applied as are indicated
in the appended claims~
