Note: Descriptions are shown in the official language in which they were submitted.
~82;~94
TOILET SO~P CONTAINING POLYMERIC THICKENER
_
Background of the Invention
This invention relates to solid toilet soap
whether it is in bar, flake, or some other solid
form, containing an effective amount of a polymeric
thickener which imparts certain advantageous
properties. Such properties particularly include
improved processibility, which results in higher line
speed and therefore, higher production; improved
texture, which translates into less cracks and a
reduced quantity of defects; improved humectant
property, which translates into protection against
weight loss upon drying or storage; and improved
quantity and quality of lather, which is indicative
of better creaminess and improved softness.
As used herein, toilet soap includes the
natural soap, synthetic detergent, and combination
soap which is a mixture of natural and synthetic
detergents. Also, the toilet soap of this invention
includes the various soaps in bar, flake, and any
other solid form. Using the more prevalent
terminology in the soap industry, in a preferred
embodiment, the solid toilet soap disclosed and
claimed herein includes soap bars, syndet bars, and
combo bars.
Natural soap is generally a saponification
product of vegetable and animal fats and oils,
particularly unsaturated fats and oils. Natural soap
can also be made from synthetic fatty acids derived
from petroleum ~ax. ~ore specif~cally, natural soap
is comprised primarily o water-soluble ammonium,
alkali metal or alkanolamine salts of various fatty
aci~s having chiefly from 12 to 18 carbon atoms.
Typical e~amples of such soap bases are lauric,
myristic, palmitic, stearic, oleic, linoleic and
linolenic acids which may be derived from various
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1~82~94
so~rces, including animal fats and oils such as
tallow, vegetable fats and oils such as coconut oil,
fish oils, whale oils, and petroleum waxes. The
sodium and potassium salts of tallow and coconut fats
are preferred, with sodium tallow/sodium coconut
soaps in the proportions of generally 90/10 to 50/50
being especially desirable. Particularly preferred
proportions of these two soap bases are 85/15 to
70/30.
Soap bars can be prepared in the following
manner beginning with neat soap. The method in which
soap is manufactured is discussed at length in
~ncyclopedia of Chemical Technology (2d Ed.) Vol. 18,
pp. 415-432. Conventionally, fatty acids or esters
thereof are saponified in a kettle process or, more
preferably, by a continuous saponification process,
to yield a neat soap containing about 30% water.
Additives are added to the neat soap, after which the
moisture level is reduced in a drier to 10-15% and
the soap is pelletized. The pelletized soap is
placed in an amalgamator and a mixture of perfume and
one oe more other additives are added. In addition,
an aqueous slurry containing other desirable
ingredients may also be added at this point.
Thereafter, the treated pellets are transferred to a
plodder which screens the soap and extrudes it into a
soap log. Soap bars are then produced from the log
by means well known in the art.
Fully synthetic bars are higher priced
specialty produ~ts which offer special properties not
available in normal or natural soaps. Syndet bars
are free of alkali and ca~ be neutral or can be
adjusted to acidic p~; they are used for certain skin
problems; they lather and clean very well at various
water hardnesses without forming a curd or
precipitate; they are compatible with a lar~e ~ariety
1~82'~94
of additives; and they use less perfume than normal
soaps.
Syndet toilet soap contains only synthetic
surfactants and generally no soap, although soap can
be included as a plasticizer/binder, as is later
explained. The combo bars, as already mentioned,
contain a combination of synthetic and normal soaps.
Generally, syndet bars comprise 30-70 parts
surfactant, 10-30 parts plasticizer/binder, 10-30
parts filler, 0-20 parts additives, and 3-10 parts
water, on weight of bars. The surfactants are
responsible for the cleansing and lathering
properties of the soap bars. Among the more
prevalent surfactants are the following: fatty
alcohol sulfates, alkane sulfonates, and acyl
isethionates. Generally, anionic, nonionic, and
amphoteric surfactants have been proposed. To obtain
good processibility and usage properties, the
surfactant portion of the syndet bars is stabilized
with plasticizers and binders, which strongly
influence lathering, wear, and sloughing
characteristics of the bars and serve simultaneously
as emmollients. Some typical examples of
plasticizers/binders include fatty alcohols,
paraffin, and fatty acids and their derivatives such
as alkanolamines, esters of polyvalent alcohols, and
even natural soap. Solid fillers are used to improve
internal structure and hardness and to reduce cost of
the bars. Examples of fillers include sodium sulfate
and similar salts, calcium and other phosphates,
talcum, puffed borax, starch, and mannitol. Other
additives are used to impart or improve certain
desired properties and to suppress undesired ones.
Overall appearance, performance, dermatological and
germicidal effects are enhanced by aditives.
Natural soap plasticity stays rather
'l282294
constant in the normal temperature operating range of
30 to 45C whereas syndet base plasticity changes
from very hard to very so~t in the same processing
range. Standard toilet soap lines are, nevertheless,
used to make syndet toilet soap and combination
toilet soap.
A plasticizer/binder in a toilet soap
prevents separation of macroscopic aggregates caused
by local stresses, which promote cracking
tendencies. It is an obvious advantage of natural
soap that the surfactant itself acts as a plasticizer
and a binder simultaneously. The polymeric
thickeners of this invention add to or enhance this
natural plasticizer/binder action of natural soap.
Summary of the Invention
The invention herein relates to solid toilet
soap, particularly toilet soap bars, containing 0.01
to 10 weight parts of a polymeric thickener, based on
100 weight parts of finished soap. The toilet soap
herein includes natural soap, synthetic detergent,
and combinations of the two. A preferred thickener
is selected from water-swellable and water-soluble
homopolymers of!an acrylic acid, especially acrylic
acid itself, and copolymers thereof with up to about
75% by weight of one or more suitable comonomers.
The resulting toilet soaps can be produced at higher
line-speeds, have less cracks and defects, have
improved humectant ~roperties which translate into
~rotection against weight or moisture loss on drying
or storage, and have improved lather quantity and
~ual~ty which translates into improved creaminess and
s~ftness ot the lather.
Detailed Description of the Invention
The invention herein is directed to the
3S incorporation of a polymeric thickener to natural,
synthetic and combination soaps in order to increase
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the production rate of such soaps, reduce cracks and
defects therein, protect soaps against moisture loss,
and to improve lather quantity and quality of
lather. The lather-enhancing attributes of the
particular thickeners useful herein result in
creamier and softer soap lathers, which are desira~le
use characteristics of toilet soap.
Although the use of common
plasticizers/binders in soaps is intended to prevent
separation of soap aggregates, as already described,
such use of plasticizers/binders unfortunately has a
deleterious effect on the soap lather. More
specifically, the use of the common
plasticizers/binders in soaps leads to reduced
quantity and quality of lather which means that the
resulting soap lather is less creamy and is not as
soft.
It was unexpectedly discovered that the use
of an effective amount of a polymeric thickener in
the toilet soap does not depress neither the quantity
nor the quality of lather but in fact enhanced these
properties while at the same time, improving the
processability parameters of toilet soap.
The invention, herein, therefore, relates to
a toilet soap containing an effective amount of a
polymeric thickener. Amount of the thickener is more
precisely defined as being 0.01 to lO weight percent,
based on the weight of the resulting soap, preferably
0.1 to 5, and more preferably 0.2 to 1 weight part.
The thickener can be added at the saponification
stage in the preparation of a natural soap or at any
other stage as long as the thickener is well admixed
with the soap base. In the preparation of syndet and
combination toilet soaps, the thickener can be added
along with other ingredients of the formulation or at
any other stage as long as it is adequately mixed
32~94
with the ingredients.
The polymeric thickeners suitable herein
are, in particular,~ synthetic thickeners which, when
used in making solid toilet soap, result in some very
5 important advantages. Based on actual use of the
thickeners in solid toilet soap, the resulting soaps
have shown improved processability, such as less
cracks, breaks or twists of soap logs, which
translates to increased line-speed in large-scale
toilet soap manufacture; improved creaminess and
softness of the soap lather which yields improved
lather quality and quantity; and a reduced level of
moisture loss due to drying of finished soap in
storage.
The synthetic thickeners contemplated herein
include commercially available polymeric thickeners
like thickeners A through I noted in Table 1,
available from The BFGoodrich Company, and other
polymeric thickeners sold under trademarks such as
Acrisint~ , Junlon~ , Rheogic~ , Acrysol~ ,
Alcoprint~ , E~A~ , Gaftex~ , and Polycarbophil~
polymeric materials. Particular thickeners in this
group found suitable herein include thickeners A
through I, referred to in Table 1, which are
available from The BFGoodrich Company; Acrisint 310
thickener, available from Sigma Chemical Company;
Junlon PW-150 and remainder of this series, available
from Showa Tsusho Company of Japan; Rheogic series,
available from Showa Tsusho Company of Japan;
Hiviswako 103 and the rest of that series, available
from Wako Pure Chemical Industries of Japan; Acrysol
ICS-l and related thickeners, availahle from Rohm &--
Haas; A~coprint PTF ~nd the related thickeners,
available from Allied Colloids of Great Britain;
EMA-91 and related thickers, available from Monsanto
Company; and Gaftex PT and similar thickeners,
,
~L2 ~ ~ 9
available from GAF Corporation.
Synthetic thickeners are generally selected
from carboxyl containing polymers and polyamides.
Preferred thickeners are selected from homopolymers
of an acrylic acid, homopolymers of alkyl acrylates,
and copolymers of an acrylic acid or an acrylic ester
with suitable comonomers or with each other. Such
thickeners can be non-crosslinked or lightly
crosslinked and can be functionally identified as
water-soluble or water-swellable. The lightly
crosslinked materials herein are crosslinked with up
to about 10% by weight of a suitable crosslinking
agent, preferably up to 5~, and especially 0.01 to
2~. The non-crosslinked synthetic thickeners are
generally soluble in water whereas the lightly
crosslinked thickeners are geneeally swellable in
water although there are some exceptions to these
generalizations. In one instance, one such thickener
is water-swellable although it is not crosslinked.
At times, it~is difficult to differentiate between
water-soluble and~water-swellable thickeners since
some are water-soluble and water dispersible.
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More particularly, the principal class of
synthetic thickeners suitable herein are the
polyacrylic acids which can be homopolymers of an
alpha, beta-olefinically unsaturated monocarboxylic
acid of 3 to 5 carbon atoms and copolymers thereof
with one or more suitable comonomers. The acrylic
acid copolymers are selected from copolymers of one
or more monounsaturated monocarboxylic acid of 3 to 5
carbon atoms copolymerized with up to about 75~ by
weight, preferably 1 to 50% and more preferably about
15 to 30~ by weight, of one or more other
copolymerizable monomers. Preferred acrylic acids
for use in this invention have the following general
structure:
R
CH2=1_cooH
wherein R is a substituent selected from the class
consisting of hydrogen, halogen, and the cyano (-C-N)
groups, monovalent alkyl radicals, monovalent aryl
radicals, monovalent aralkyl radicals, monovalent
alkaryl radicals and monovalent cycloaliphatic
radicals. Of this class, acrylic and methacrylic
acid are most preferred because of generally lower
cost, ready availability and ability to form superior
polymers.
Suitable comonomers are selected from alkyl
acrylates represented ~y the following formula
R'O
1 11
CH2=C-C-o-R
where R' is hydrogen, methyl, or ethyl group; and R
is an alkyl group of 10 to 30, preferably 10 to 20
carbon atoms; R can also be selected from alkyl,
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~8~94
alkoxy, haloalkyl, cyanoalkyl, and the like groups,
containing 1 to 9 carbon atoms. Representative
acrylates include methyl acrylate, ethyl acrylate,
propyl acrylate, isopropyl acrylate, butyl acrylate,
isobutyl acrylate, methyl methacrylate, methyl
ethacrylate, ethyl methacrylate, octyl acrylate,
heptyl acrylate, octyl methacrylate, isopropyl
methacrylate, 2-ethylhexyl acrylate, nonyl acrylate,
hexyl acrylate, n-hexyl methacrylate, decyl acrylate,
isodecyl methacrylate, lauryl acrylate, stearyl
acrylate, behenyl acrylate, melissyl acrylate and the
corresponding methacrylates. Mixtures of two or
three or more of the acrylic esters may be
successfully polymerized with one of the carboxylic
acid monomers. One useful class of copolymers are
those methacrylates where the alkyl group contains 10
to 20 carbon atoms. Typical polymers have been made
with about 15 weight percent isodecyl methacrylate,
about 10 weight percent lauryl methacrylate, and
about 7 weight percent stearyl methacrylate, with
acrylic acid.
Other vinylidene comonomers may also be
used, particularly in conjunction with acrylic
esters, including the acrylic nitriles,
-olefinically unsaturated nitriles useful in the
interpolymers embodied herein, preferably the
monoolefinically unsaturated nitriles having from 3
to 10 carbon atoms such as acrylonitrile,
methacrylonitrile, ethacrylonitrile,
chloroacrylonitrile, and the like. Most preferred
are acrylonitrile and methacrylonitrile. The amounts
used, for exampl~, for some polymers are from about 5
to 30 weight percent of the total monomers
copolymerized.
35- Acrylic amides include monoolefinically
unsaturated amides that may be incorporated in the
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interpolymers of this invention having at least one
hydrogen on the amide nitrogen and the olefinic
unsaturation is alpha-beta to the carbonyl group.
Very much preferred are acrylamide and methacrylamide
used in amounts, for example, from about 1 to 30
weight percent of the total monomers copolymerized.
Other acrylic amides include N-alkylol amides of
alpha, beta-olefinically unsaturated carboxylic acids
indluding those having from 4 to 10 carbon atoms.
The preferred mono~ers of the N-alkylol amide type
are the N-alkylol amides of alpha,
beta-monoolefinically unsaturated monocarboxylic
acids and the most preferred are N-methylol
acrylamide and N-methylol methacrylamide used in
amounts for example of about 1 to 20 weight percent.
N-alkoxymethyl acrylamides also may be used. The
preferred alkoxymethyl acrylamides are those wherein
the alkyl group contains from 2 to 5 carbon atoms and
useful is N-butoxymethyl acrylamide.
Other vinylidene comonomers generally
include, in addition to those described above, at
least one other olefinically unsaturated monomer,
more preferably at least one other vinylidene monomer
(i.e., a monomer containing at least one terminal
CH2-C ~ group per molecule) copolymerized
therewith, for example up to about 30% or more by
weight of the total monomers. Suitable monomers
include a -olefins containing from 2 to 12 carbon
atoms, more preferably from 2 to 8 carbon atoms, such
as ethylene and propylene; dienes containing from 4
to 10 carbon atoms, including butadiene; vinyl esters
and allyl esters such as vinyl acetate; vinyl
aromatics such as styrene; vinyl and allyl ethers and
ketones such as vinyl methyl ether and methyl vinyl
ketone; cyanoalkyl acrylates such as a -cyanoalkyl
acrylates, the a-, ~- and Y -cyanopropyl acrylates,
.,,
1~8;2f~9~
11
vinyl halides and vinyl chloride, vinylidene chloride
and the like; esters of maleic and fumaric acid and
the like.
It should be understood that synthetic
thickeners can be devoid of a monounsaturated
monocarboxylic acid or they can contain one or more
of such acids together with one or more other acids
and/or comonomers. In such cases, the thickeners are
based on acrylic esters wherein such esters are
present in an amount greater than 50%, preferably in
excess of 70% by weight of all monomers.
The polyacrylic acids described herein can
be crosslinked with a suitable polyfunctional
vinylidene monomer containing at least two terminal
CH2-C ~ groups, including for example, butadiene,
isoprene, divinyl benzene, divinyl naphthlene, allyl
acrylates and the like. Particularly useful
cross-linking monomers for use in preparing the
copolymers, if one is employed, are polyalkenyl
polyethers having more than one alkenyl ether
grouping per molecule. The most useful possess
alkenyl groups in which an olefinic double bond is
present attached to a terminal methyle~e groups,
CH2=C < . They are made by the etherification of
a polyhydric alcohol containing at least 4 carbon
atoms and at least 3 hydroxyl groups. Compounds of
this class may be produced by reacting an alkenyl
halide, such as allyl chloride or allyl bromide, with
a strongly alkaline aqueous solution of one or more
poly~ydric alcohols. The product is a complex
mixture of polyethers with varying numbers of ether
groups. Anal~sis reveals the average number of ether
groupings on each molecule. Efficiency of the
polyether cross-linking agent increases with the
3s number of potentially polymerizable groups on the
molecule. It is preferred to utilize polyethers
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1'~82~94
12
containing an average of ~wo or more alkenyl ether
groupings per molecule. ~t~ler cross-linking monomers
include for example, diallyl esters, dimethallyl
ethers, allyl o~ ~ethallyl acrylates and acrylamides,
tetraallyl tin, tetravinyl silane, polyalkenyl
methanes, diacrylates, and dimethacrylates, divinyl
compounds as divinyl benzene, polyallyl phosphate,
diallyloxy compounds and phosphite esters and the
like. Typical agents are allyl pentaerythritol,
allyl sucrose, trimethylolpropane triacrylate,
1,6-hexanediol diacrylate, trimethylolpropane diallyl
ether, pentaerythritol triacrylate, tetramethylene
dimethacrylate, tetramethylene diacrylate, ethylene
diacrylate, ethylene dimethacrylate, triethylene
glycol dimethacrylate, and the like. Allyl
pentaerythritol, allyl sucrose and trimethylolpropane
diallyl ether provide excellent polymers in amounts
less than 5, as less than 3 weight percent, and
particularly about 0.1 to 2.0% by weight of all
monomers.
For purposes of clarification, it is pointed
out that, generally speaking, the lightly crosslinked
synthetic thickeners described herein swell in water
whereas the non-crosslinked thickeners are soluble in
water. Both types, however, are suitable in the
invention herein.
The preferred polyacrylic acid homopolymers
and copolymers useful herein, as described, include
crosslinked and non-crosslinked polymers prepared in
an organic solvent, especially benzene, have
molecular weights in the range of about 200,000 to
5,000,000. Especially preferred are lightly
crosslinked polyacrylic acid homopolymers of acrylic
acid itself in the molecular weight range of about
500,000 to 4,000,000. The polyacrylic thickeners are
in acid form which may be neutralized to a salt form
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1~8Z~94
for use in ~he in~ention described herein.
Other pol;~ca~boxylic resins, such as
thickener H or thickener I in Table 1, are lightly
crosslinked, swellable resin polymers containing a
carboxylic acid as a major component. These
materials are polymerized in an aqueous solution of a
soluble nonredox divalent inorganic ion, such as
magnesium sulfate. The salt is normally used at a
level of above about one-half molar. The major
component can be homopolymerized or copolymerized
with a suitable comonomer.. Suitable carboxylic acids
include monounsaturated monocarboxylic and
dicarboxylic acids containing 3 to 5 carbon atoms,
salts thereof and anhydrides thereof. Specific
examples thereof include acrylic acid and salts
thereof, methacrylic acid and salts thereof, fumaric
acid, maleic acid and its anhydride, itaconic acid,
and the like. ~crylic acid is preferred.
Polyunsaturated copolymerizable crosslinking agents,
which form a minor component of these resins, have
two or more double bonds subject to crosslinking with
the monomers and can be aromatic or aliphatic. As
disclosed in Example 1 of U.S. Patent 2,810,716, such `
resins can be obtained by preparing a mixtu~e of 100
grams of acrylic acid, 1.2g of divinyl benzene, and
1.0g of benzoylperoxide. This mixture is added to an
aqueous saturated magnesium sulfate so~ution and
heated to 95C. After 16 minutes, 100.5g of the
resin is o~tained, which is highl~I swelling. Such
~G resins aLe ~e~ .no~n in the art.
Polymerization of one or more monomers of
the synthetic thickener described herein in the
solvent or diluent medium is usually carried out in
the presence of a free radical catalyst in a closed
vessel and also in an inert atmosphere under
autogenous pressure or artifically-induced pressure,
X
8~ 94
or in an open vessel under reflux at atmospheric
pressure. Temperature of the polymerization may be
varied from about 0 to 100C or lower or higher,
depending to a degree on the molecular weisht desired
in the polymer. Polymerization at 25 to 90C under
autogenous pressure using a free radical catalyst is
generally effective in producing polymer yields of
75% to 100%. Typical free radical forming catalysts
include peroxygen compounds such as sodium, potassium
and ammonium persulfates, caprylyl peroxide, benzoyl
peroxide, hydrogen peroxide, pelargonyl peroxide,
cumene hydroperoxides, tertiary butyl diperththalate,
tertiary butyl perbenzoate, sodium peracetate, sodium
percarbonate, and the like, as well as azo catalysts
and azodiisobutyryl nitrile, hereinafter referred to
as azoisobutyronitrile. Other catalysts utilizable
are the so-called "redox" type of catalyst and the
heavy-metal activated catalyst systems. Ultra-violet
light may also be used as a source of free radicals.
Some systems polymerize solely by heat, but catalysts
provide better control. The monomer may be batch
charged or continuously added during the course of
polymerization, or by any other manner of
polymerization techniques conventionally used.
As stated, the polymerizations are normally
conducted in inert diluents having some solubilizing
effect on one or more of the monomeric ingredients
but substantially none on the resulting polymers. In
other words, the medium used for the polymerization
is one-in which the monomers are preferably soluble
and the polymer is substantially insoluble. Such
materials are normally organic liquids which are
solvents for the monomers but are nonsolvents for the
polymers, or a mixture of such solvent so that the
polymer product is preferably obtained as a very fine
friable or fluffy precipitate. Typical solvents
~'~82'~94
include hydrocarban~ conti~nil~ ~ to 8 carbo~ atoms,
benzene, xylene, te~ralin, hexane, .,eptane,
cyclohexane, carbon tetrachloride, chloroform,
trichloroethylene, methyl chloride, ethyl chloride
and methylene chloride; chlorofluoroalkanes such as
chlorofluoromethane and chlorofluoroethane containing
at least four halogen atoms; esters such as methyl
acetate, ethyl acetate and butyl propionate; ketones
such as methylethylketone, acetone, and dioxane;
alcohols including methanol, ethanol, butanol,
mineral spirits and the like. The amount of organic
medium used normally will be in excess of the
monomers to be polymerized and the proportion may
vary from at least l weight percent of monomers and
99 weight percent organic medium up to about 50
weight percent monomers and 50 weight percent organic
medium. Normally, a concentration of about 5 to 20
weight percent organic monomers is employed.
Excellent results have been obtined with mineral
2~ spirits having a flasn point greater at 12CF
containing 0 to 2% aromatics 40 to 85~ paraffins and
15 to 50% naphthenes.
In the practice of the invention, any of the
general types of nonionic and anionic surfactants may
be employed in the preparation of polymeric
thickeners. The use of nonionic surfactants is
preferred.
It is confirmed herein that the toilet soap
of this invention has improved processability which
translates to increased production rate in large
scale manufacture of toilet soap. It is also
confirmed herein that the soap of this invention has
improved texture and improved lather quality and
quantity yielding a soap lather that is creamier and
softer whereas, as noted herein, the use of common
plasticizers depresses lather formation. Lastly, it
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is also confirmed herein that the improved toilet
soap claimed herein exhibiL~ ~ r~duced leve~ of
moisture loss due to ~rying or storage.
In addition to the specific ~ata presented
hereinbelow, certain general da~a and observat~ons
can also be made in support of the above
allegations. Although it is difficult to generalize,
it has been, nevertheless, found that control toilet
soap without the thickeners described herein, yields
soap lather volume of about 180 ml whereas wi~h 1~
thickener of this invention, the soap lather volume
is about 220 mls. Furthermore, whereas control soap
lather has viscosity of about 600 cps, the soap of
this invention, containing 1% of a thickener, has
viscosity of 1100 to 1500 cps. Also, whereas control
soap has a density of about 41 grams per soap bar,
the soap of this invention with 1% thickener, has
density of about 41 to 44 grams per bar. Lastly,
hhereas control soap has weight loss on storage of
about 13~, the soaps containing about 1~ polymeric
thickeners have weight loss of 6-9~. It has also
been observed that the presence of a thickener
reduces dramatically the average size of bubbles,
which is indicative of improved creaminess.
The differences noted above, between soap
with and without a thickener disclosed herein, are
substantial differences which result in significant
advantages. The thickeners disclosed herein impart
varyinq degrees of improvement in terms of advantages
3~ ~iscussed above.
The examples that follow, demonstrate
certain features of the invention in greater detail
with respect to preparation of a preferred thiGkener,
and use of various thickeners in toilet soap bars
which result in advantages of greater production
rate, improved texture of the resulting soap,
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~.282~94
improved humecant property of the resulting soap, and
better quality and higher quantity oE lather from the
soap.
xam~le 1
S This example demonstrates preparation of a
polyacrylic acid from the following formulation,
given in weight parts:
acrylic acid 100
allyl pentaerythritol 0.2
lauroyl peroxide 0.3
benzene 500
Polymerization was carried out under
autogeneous pressure at 78C until reaction was
complete in about 5 hours. The polymer produced,
after removing benzene, was in the form of a fine,
friable powder of about 1,000,000 molecular weight.
For the particular application contemplated herein,
the product was used in acid form although it can be
neutralized with an alkali, such as sodium or
potassium hydroxide, to develop its thickening
properties. Since this product was lightly
crosslinked, it was water-swellable and water
dispersible.
Example 2
This example demonstrates preparation of
toilet soap bars with various synthetic
thickeners and testing thereof to evaluate processing
characteristics, lather quality and quantity, soap
bar density, and moisture loss thereof on storage.
~or the sa~e of clarification, neat soap
base is usually prepared by saponification of
fats/oils that contain 12 to 18 carbon atoms. For
purposes herein, soap base pellets containing 9.5%
moisture of 85% tallow and 15% coconut oil mixture
were obtained from a commercial source and charged
into an amalgamator. The thickeners were added to
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lX82X94
18
the pelletized neat soap in the amalgamator, although
they can be added at the saponif~cation st~3.e o~ a~
any other stage of toilet soap preparation. Since
neat so,ap contained 9.5~ ~oistur~, additional
deminerali~ed water was added to a~just ~oisture o~
finished toilet soap to 15%. The recipe used for
purposes o~ this example was as follows, given in
weight parts:
neat soap base pellets lO00 grams
polymeric thickener lO grams
water (DM) 80 grams
Total soap mass 1090 grams
The above soap mass was mixed in the
amalgamator for 45 minutes and then transferred to
the plodder where it was subjected to two passes
using a noodle die and then to three passes using a
rectangular log die. The soap log was then cut into
uniform soap bars of 2-l/2"xl-l/2"x3/4" (6.25 cm x
3.75 cm x 1.88 cm). The operation described above
was carried out with a 2.5 Lab Soap Processor
equipment of Houchin Soap Machine Company, Division
of Hughes Industries situated in Cinnaminson, N.J.
During the final pass of the soap mass
through the plodder, the following processing
characteristics were assessed:
(a) log breaks during extrusion - judged on
the basis of the length of the soap log before it
broke into shorter lengths;
(b) twists during extrusion - judged on the
basis of w~ether the soap log was straight or
slightly ~wisted;
~c) cracks/chips in soap bars - judged on
the basis cracks/chipS on the ~ut face of the soap
bars.
35` The processing characteristics were
identified by a "yes" or a "no" and a negative
8Z'~94
indication to any one of the three items identified
above signified good processability.
Lather volume was determined by a
standardized hand-lathering procedure which involved
washing of hands thoroughly using a particular toilet
soap bar in tap water having 135 ppm as CaCo3
hardness and a 2:1 ratio of calcium to magnesiu~,
adjusted to 40C. This procedure specif ically
required the following:
(a) thoroughly wetting the soap bar;
(b) taking the wet soap bar in both hands
and giving it 10 twisting motions in the usual
manner, and laying the soap bar aside;
(c) rubbing hands back and forth 10 times
to generate lather;
(d) removing lather so formed by squeezing
each hand back and forth and transferring the lather
to a graduated beaker;
(e) repeating steps (a) to (d) fou~ more
times; and
(f) reading and recording the milliliters
of later so obtained.
Lather viscosity was determined on the
lather obtained from the later volume test by
measuring its viscosity at a shearing rate of 13.91
sec 1 at 30C with a Brabender Rotational
Rheoviscometer. Viscosity was recorded in
centipoises, or cps.
Weight loss of soap bars was determined by
initially recording the initial weight (Wi) of the
bars. The bars were then placed in an oven
maintained at 45CC with forced air circulation and
their weight was again recorded at end of 14 days
(W14). The weight percent loss was calculated as
follows:
1~2~94
Wi ~ W14
% Weight Loss = xlO0
Wi
Results of the tests are given in Table 1, below:
1'~8Zi~94
--21:--
U~
o
.:1 ~ ~1 ~-- (~I 11 ~P ~D ~ O G
V . .... ~ . . . . . . . .
3 ~ ~D ~ X 1~
c~j) r~l
E
. ~ CO ~ ~ ~ Ln o ~ o o
v ~ O ~ t~l ~ o t~ ~r _I .-1 ~ t`l
.
t~ U~ ~ 1~1 G ~ D O
U~ ~ ~ O O
~> ~.) O ~
V
1~
_~_I _I O ~ O ~ O O O U~ O ~ 0~ 0
O E co a~ ~ o ~ o ~ ~ ~ co o
~~ --
m ~ _
.E~ ~ ~ O O
.
~ U ~OOOOOOOOO OO
~ 'I
O u~ 0 E e E o~ u~
3 ~ O O o O O O O ~ a~ O o
E~ ~ u~ z z u~ u~ Z Z ~ ~ Z Z
1 ~1
¦ ¦ a Z Z Z Z Z Z Z
~s m ~ a ~ ~ ~ ~r ~
~J ~ ~ U Ll ~ ~ ~ ~ ~I
c ~ c c c c - c c c c
a) O ~ ~ O c~ C O
~ ~ Y Y
t~ v o ~ v ~
C ~ ~rJ ~ ~1 ~ .~1 ~ ~ .~1 Ll O C
s o s s s ~c s s s s s t~
E~ u~ o u~
~28~94
--2~--
U~
O
.
3 1` t~
o~P
m ~ a~
e 3 O ~ ~ o
_~ O~ I ~r o c~ 0~0 ,
:~ ~1 6
C l~ E I r~ o o r-- In
_~ C
a~ s
. ¦ hE,E, E, E,
~Q
U~ U~
~ 3 0
. ~
: ~ m x æ zz z
U O L~E~
a~ ~ c
C ~0 0 ~~-1 X
~ ~ I o I ~
E~ ~
C U~ O
.,
'. ' ., -, ~-:
.
1~8~94
In Ta~le l, Thickener A was non-crosslinked,
water-soluble polyacrylic acid homopolymer prepared
in benzene having molecular weight of 450,000;
Thickeners B to F were lightly crosslinked
polyacrylic acid homopolymers prepared in benzene and
having molecular weights in the range of 750,000 to
4,000,000; Thickener G was a lightly crosslinked
copolymer of a major proportion of acrylic acid and a
minor proportion of fatty acid methacrylate also
prepared in benzene; Thickeners H and I were also
lightly crosslinked polyacrylic acid hompolymers
prepared in water and having high molecular weight
exceeding one million; Acrisint 310, Junlan PW-150,
and Hiviswako 103 are known to be lightly crosslinked
commercial polyacrylic acid homopolymers; and Acrysol
ICS-l, Alcoprint PTF, E~A-91, and Gaftex PJ
thickeners are known to be commerical acrylic acid
copolymers.
