[0001] The present invention relates to improvements in soap compositions for use on the
skin. The improvements reside in the formulation of soap compositions which contain
certain nitrogen-based conditioning agents. These conditioning agents are salts wherein
the cation moiety is a protonated fatty amine or a fatty quaternary ammonium ion and
the anion moiety is the anion of a fatty acid soap or an anionic synthetic detergent.
The conditioning agents are present at levels of from about 0.25% to 25% by weight
in the composition.
BACKGROUND ART
[0002] The most commonly used agent for cleansing the skin is soap. It has long been recognized
that the cleansing of the skin with soap tends to remove natural oils from the skin,
thereby causing dryness and roughness as well as a sensation of discomfort in the
skin. Dryness and roughness can be perceived tactually by rubbing one's fingers across
the skin and will be referred to herein as "external skin feel". Discomfort of the
skin without touching (perceived as skin "tension" or "tightness") is felt internally
by the person whose skin has been cleansed with soap and will be referred to herein
as "internal skin feel". This internal feel is most readily perceived immediately
after washing and drying of the skin.
[0003] There have been many attempts to alleviate the adverse skin effects caused by soap,
by incorporating into soap compositions a variety of mildness additives. These have
included vegetable oils, mineral oils, free fatty acids, fatty acid esters of polyols,
and the like. While these materials tend to'alleviate the negative effects of soap
upon the skin, there is a continuing need for improved skin conditioners to be used
with soap.
[0004] The object of the present invention is to provide soap compositions which are effective
in cleansing the skin and are highly effective in alleviating the adverse effects
on skin feel (especially external skin feel) which normally accompany the use of soap
on the skin.
DISCLOSURE OF INVENTION
[0005] According to the present invention, it has been found that certain salts wherein
the cation moiety is a protonated fatty amine or a fatty quaternary ammonium ion,
and the anion moiety is the anion of a fatty acid soap or an anionic synthetic detergent
are effective in alleviating the adverse effects on external skin feel caused by washing
the skin with soap.
[0006] The present invention encompasses skin cleansing compositions which comprise:-
a. from about 3% to about 95% by weight of a soap selected from the group consisting
of-alkali metal salts of fatty acids containing from about 8 to about 20 carbon atoms
and mixtures of said soaps; and
b. from about 0.25% to about 25% of a skin conditioning agent selected from compounds
having the formulas:




and

-wherein R1, R2, R3 and R4 are each selected from the group consisting of hydrogen and aliphatic hydrocarbyl
groups containing from 1 to about 24 carbon atoms, with at least one of R1, R2, R3 and R4 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R5, R6, R7, R8 and R9 are each selected from the group consisting, of hydrogen and aliphatic hydrocarbyl
groups containing from 1 to about 24 carbon atoms with at least one of R5, R6, R7, R8 and R9 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R10, R11, R12, R13, R14 and R15 are each selected from the group consisting of hydrogen and C1 to C24 aliphatic hydrocarbyl groups with at least one of R10, R11, R12, R13, R14 and R15 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R16, R17 and R18 are each selected from the group consisting of hydrogen and aliphatic hydrocarbyl
groups containing from about 1 to about 24 carbon atoms, with at least one of R16, R17 and R18 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R19, R20, R21 and R22 are each selected from the group consisting of hydrogen and aliphatic hydrocarbyl
groups containing from 1 to about 24 carbon atoms, with at least one of R19, R20, R21 and R22 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein n is an integer of from 1 to about 20, wherein m is an integer of from 2 to
about 20, and wherein A is an anion which is selected from the group consisting of
the anions of fatty acid soaps and anionic synthetic detergents. The term "hydrocarbyl"
as used herein refers to a radical which consists of hydrogen and carbon atoms.
[0007] All percentages herein are "by weight" unless specified otherwise.
THE SOAP COMPONENT
[0008] The soap component of the present compositions is an alkali metal (e.g., sodium or
potassium) soap or mixture of soaps of fatty acids containing from about 8 to about
24, preferably from about 10 to 20 carbon atoms. The fatty acids used in making the
soaps can be obtained from natural sources such as, for instance, plant or animal-derived
glycerides (e.g., palm oil, coconut oil, babassu oil, soybean oil, castor oil, tallow,
whale oil, fish oil, tallow, grease, lard and mixtures thereof). The fatty acids can
also be synthetically prepared (e.g., by oxidation of petroleum stocks or by the Fischer-Tropsch
process).
[0009] Alkali metal soaps can be made by direct saponification of the fats and oils or by
the neutralization of the free fatty acids which are prepared in a separate manufacturing
process. Particularly useful are the sodium and potassium salts of the mixtures of
fatty acids derived from coconut oil and tallow, i.e., sodium and potassium tallow
and coconut soaps.
[0010] The term "tallow" is used herein in connection with fatty acid mixtures which typically
have an approximate carbon chain length distribution of 2.5% C
14, 29% C
16' 23% C
18, 2% palmitoleic, 41.5% oleic and 3% linoleic (the first three fatty acids listed
are saturated). Other mixtures with similar distribution, such as the fatty acids
derived from various animal tallows and lard, are also included within the term tallow.
The tallow can also be hardened (i.e., hydrogenated) to convert part or all of the
unsaturated fatty acid moieties to saturated fatty acid moieties.
[0011] When the term "coconut oil" is used herein it refers to fatty acid mixtures which
typically have an approximate carbon chain length distribution of about 8% C
8, 7% C
10,
48% C12,
17% C14,
9% C16' 2% C
18, 7% oleic, and 2% linoleic (the first six fatty acids listed being saturated).
[0012] Other sources having similar carbon chain length distribution such as palm kernel
oil and babassu kernel oil are included with the term coconut oil.
[0013] When compositions of the present invention are prepared in the form of toilet bars,
the soap component is preferably either sodium soap or a mixture of sodium and potassium
soap wherein the mixture contains no more than about 25% by weignt potassium soap.
[0014] Also, it is preferable in such bars that the total soap component comprises (a) from
about 20% to 80% by weight of the soap component of a mixture containing soaps having
from 8 to 14 carbon atoms and (b) from about 20% to 80% by weight of the soap component
of soaps having from about 16 to 20 carbon atoms.
[0015] Soaps having such preferred chain length distribution characteristics can be realized
by utilizing mixtures of tallow and coconut fatty acids in tallow/coconut weight ratios
varying between 90:10 and 50:50.
[0016] The soap compositions herein can also contain free fatty acids having carbon chain
lengths of from about 8 to 18. The presence of such free fatty acids tends to improve
the speed and volume of lathering of the composition and confers a creamy feel to
the lather. When free fatty acids are utilized in the compositions herein, they are
generally present at levels of from about 5% to about 25% of the total amount of soap.
[0017] Toilet bars containing the above-described soap -mixtures, as well as their manufacture,
are described in more detail in Megson et al, U.S. Patent No. 3,576,749, issued April
27, 1971, and White, U.S. Patent No. 3,835,058, issued September 10, 1974. Both of
these patents are incorporated herein by reference.
THE SKIN CONDITIONING COMPONENT
[0018] The skin conditioning component of the present compositions is selcted from the group
of compounds having the formulas:

, and

wherein R
1, R
2, R
3 and R
4 are each selected from the group consisting of hydrogen and aliphatic hydrocarbyl
groups containing from 1 to about 24 carbon atoms, with at least one of R
1, R
2, R
3 and R
4 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R
5, R
6, R
7, R
8 and R
9 are each selected from the group consisting of hydrogen and aliphatic hydrocarbyl
groups containing from 1 to about 24 carbon atoms with at least one of R5, R
6, R
7, R
8 and R
9 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R
10, R
11, R
12, R
13, R14 and R15 are each selected from the group consisting of hydrogen and
C1 to
C24 aliphatic hydrocarbyl groups with at least one of R
10, R
11, R
12, R
13' R
14 and R
15 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R
16, R
17 and R
18 are each selected from the group consisting of hydrogen and aliphatic hydrocarbyl
groups containing from 1 to about 24 carbon atoms, with at least one of R
15, R
17 and R
18 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein R
19, R
20, R
21 and
R22 are selected from the group consisting of hydrogen and aliphatic hydrocarbyl groups
containing from 1 to about 24 carbon atoms, with at least one of R
19, R
20, R
21 and
R22 being an aliphatic hydrocarbyl group containing from about 8 to about 24 carbon atoms,
wherein n is an integer of from 1 to about 20 (preferably from 1 to about 4), wherein
m is an integer of from 2 to about 20 (preferably 2 to 4) and wherein A is an anion
which is selected from the group consisting of the anions of fatty acid soaps and
anionic synthetic detergents.
[0019] These skin conditioning compounds are salts. The cation moiety of the salt is a protonated
fatty amine or protonated imidazoline moiety or a quaternary ammonium or imidazolinium
moiety. For example, in Formula I, whenone or more of the "R" groups is hydrogen,
the cation is a protonated amine moiety. If all four "R" groups are hydrocarbyl groups,
the cation is a quaternary ammonium moiety.
[0020] Amines can be protonated by reacting them with an acidic material (e.g., HC1 or acetic
acid). The resulting compound is a protonated amine salt, e.g., an amine hydrochloride
or an amine acetate. Amines which are protonated to provide cation moieties for the
present invention can be primary, secondary or tertiary amines, and must contain at
least one aliphatic hydrocarbyl group of from 8 to 24 carbon atoms. Examples of such
amines are dodecylamine, methyl octadecyl amine, dimethyl hexadecyl amine, didodecyl
methyl amine, ethyl dodecyl octadecyl amine, N-tetradecyl, N'propyl-1,3-propane diamine,
l-stearylamidoethyl-2-stearyl imidazoline and 1-ethylene bis(2-stearyl imidazoline).
Examples of protonated amine salts formed from these amines are dodecylamine acetate,
methyl octadecyl amine hydrochloride, dimethyl hexadecylamine hydrochloride, didodecyl
methyl amine acetate,ethyl dodecyl octadecyl amine acetate, N-tetradecyl, N'-propyl-1,3-propane
diamine dihydrochloride, I-stearylamidoethyl-2-stearyl imidazolinium hydrochloride
and 1-ethylene bis(2-stearylimidazolinium)dihydrochloride. Such amine salts can be
used to provide the protonated amine moiety which can serve as the cation of the skin
conditioning agents of the present invention.
[0021] The quaternary ammonium ions are the cations which are formed by quaternizing a tertiary
aliphatic amine with an additional aliphatic group. This is accomplished by reacting
a tertiary amine with an alkylating agent such as methyl chloride. For example, if
didodecyl methyl amine is reacted with methyl chloride, the resulting quaternary ammonium
salt is didodecyldimethylammonium chloride. Examples of specific quaternary ammonium
salts which can be used to provide the quaternary ammonium cation moiety for the skin
conditioning agents herein are didodecyldimethylammonium chloride, dodecyltrimethylammonium
bromide, dihexadecyldimethylammonium acetate, N,N'-ditetradecyl-N, N,N',N'-tetramethyl-1,3-propyl
diammonium dichloride, N,N'- distearyl-N,N,N',N'-tetramethyl-1,10-decyl diammonium
diacetate, l-methyl-l-stearylamidoethyl-2-stearyl imidazolinium methyl sulfate and
1-ethylene bis(2-stearyl, 1-methylimidazolinium) dichloride.
[0023] In the case where the cationic moiety is a protonated amine or imidazoline, the conditioning
agent can also be prepared by reacting the free amine or imidazoline with a fatty
acid (instead of a soap) or the acid form of the synthetic detergent (instead of the
salt form of the detergent). For example:-

[0024] The anionic moiety of the skin conditioning agent herein can be the anion of a fatty
acid soap (i.e., the radical

wherein R
23 is a C
7 to C
23 aliphatic group) or the anion of an anionic synthetic detergent. Any anionic synthetic
detergent can be used to provide the anion moiety for the skin conditioning agents
herein. The most common types of anionic synthetic detergents are the water soluble
salts (e.g., sodium, potassium, lithium or.ammonium) of organic sulfuric reaction
products having in their molecule an aliphatic group containing from about 8 to about
24 carbon atoms, and a sulfonic or sulfuric acid ester radical. Synthetic detergents
containing a C
8 to C
24 aliphatic group and having a carboxylic acid radical instead of a sulfonic or sulfuric
acid ester radical can also be used. Examples of anionic synthetic detergents which
can provide the anion moiety of the skin conditioning agents herein include the following:
1. Alkyl sulfates of the formula

wherein R24 is an alkyl (straight or branched chain) of from 8 to 24 carbon atoms and M is an
alkali metal or ammonium ion. Specific examples are sodium dodecyl sulfate and potassium
hexadecyl sulfate.
2. Alkyl sulfonates of the formula

wherein R24 and M are as defined in (l)above. These surfactants are also called paraffin sulfonates.
Specific examples are sodium dodecyl sulfonate and ammonium octadecyl sulfonate.
3. Alkyl ether sulfates of the formula

wherein R24 and M are as defined in (1) above and wherein x is a number of from 1 to 10. Specific
examples are C14H29(OC2H4)3OSO3Na and C18H37(OC2H4)5K.
4. Alkyl monoglyceride sulfonates of the formula

wherein y is a number of from 1 to 4, X is selected from the group consisting of chlorine,
hydroxyl and -SO3M, at least one X in each molecule being SO3M, and wherein R24 and M are defined as in (1) above (see U.S. Patent 3,024,273 incorporated herein
by reference). A specific example is

5. Alkyl benzene sulfonates of the formula

wherein R24 and M are as defined in (1) above. Specific examples are dodecylbenzene sodium sulfonate
and tridecylbenzene potassium sulfonate.
6. Acyl lactylates of the formula

wherein R24 and M are as defined in (1) above, and z is usually a number of from 1 to 3. A specific
example is sodium stearoyl-2-lactylate.
[0026] Examples of preferred skin conditioning agents of the present invention are stearylammonium
laurate, ztearylammonium stearate, distearyldimethylammonium laurate, and distearyldimethylammonium
stearate.
[0027] Generally the ratio of soap to conditioning agent in the compositions herein will
be from about 1:1 to about 100:1, preferably from about 3:1 to about 20:1.
OPTIONAL COMPONENTS
[0028] The soap compositions of the present invention will normally contain water. When
the compositions are in the form of a lotion or cream, the water content will be of
the order of 50% to about 95%. When the compositions are formulated into toilet bars,
the water content will normally be of the order of 20% or less.
[0029] Conventional antibacterial agents can be included in the present composition at levels
of from about 0.5% to about 4%. Typical antibacterial agents which are suitable for
use herein-are 3,4-di- and 3,4',5-tribromo- salicylanilides; 4,4'-dichloro-3-(trifluoromethyl)
cabanilide; 3,4,4'-trichlorocarbanilide and mixtures of these materials.
[0030] Conventional nonionic emollients can be included as additional skin conditioning
agents in compositions of the present invention at levels up to about 40%, preferably
at levels of from about 1% to about 25%. Such materials include, for example, mineral
oils, paraffin .wax having a melting point of from about 100°F to about 170°F, fatty
sorbitan esters (see U.S. Patent 3,988,255, Seiden, issued October 26, 1976 incorporated
herein by reference), lanolin and lanolin derivatives, esters such as isopropyl myristate
and triglycerides such as coconut oil or hydrogenated tallow. These nonionic-type
skin conditioning agents appear to primarily contribute internal skin feel advantages
to the compositions herein, whereas the aforedescribed protonated amine or quaternary
salt conditioning agents appear to primarily contribute external skin feel advantages.
[0031] Free fatty acid such as coconut oil fatty acid can be added to the compositions herein
to improve the volume and quality (creaminess)of the lather produced by the compositions
herein.
[0032] Conventional perfumes, dyes and pigments can also be incorporated into compositions
of the invention at levels up to about 5%. Perfumes are preferably used at levels
of from about 0.5% to 3% and dyes and pigments are preferably used at levels of from
about 0.001% to about 0.5%.
[0033] Synthetic detergents can also be present in compositions herein. Preferred types
of synthetic detergents are of the anionic or nonionic type. Examples of anionic synthetic
detergents are the salts of organic sulfuric reaction products described in (1) through
(5) hereinbefore. Examples of nonionic synthetic detergents are ethoxylated fatty
alcohols (e.g., the reaction product of one mole of coconut fatty alcohol with from
about 3 to 30 moles of ethylene oxide, the reaction product of one mole of coconut
fatty acid with from about 3 to 30 moles of ethylene oxide and fatty acid amides such
as coconut fatty acid monoethanolamide and stearic acid diethanolamide. Although it
may be desirable in some instances to incorporate synthetic detergents into the compositions
of the present invention, the compositions herein can be free of synthetic detergents.
Synthetic detergents when present are normally employed at levels of from about 5%
to about 400% by weight of the amount of soap in the compositions.
[0034] Insoluble alkaline earth metal soaps such as calcium stearate and magnesium stearate
can also be incorporated into compositions of the present invention at levels up to
about 30%. These materials are particularly useful in toilet bars in which synthetic
detergents are present in that they tend to reduce the relatively high solubility
which such bars normally have. These alkaline earth metal soaps are not included within
the term "soap" as otherwise used in this specification. The term "soap" as used herein
refers to the alkali metal soaps.
[0035] Lotions or creams can optionally contain thickeners or phase stabilizers such as
carboxymethyl cellulose or xanthum gum.
COMPOSITION PREPARATION
[0036] The compositions of the present invention can be prepared in the form of toilet bars,
or if desired, in the form of creams or lotions. The toilet bar is the most preferred
form since this is the form of cleansing agent most commonly used to wash the skin.
[0037] Preferably the toilet bars are made from a mixture of soaps derived from coconut
oil and hydrogenated tallow, the ratio of coconut soap to tallow soap being from about
1:1 to about 1:4. The toilet soap compositions generally contain from about 5% to
about 20% moisture.
[0038] Toilet bars of the.present invention can be prepared in the conventional manner.
Moisture-containing base soap can be admixed with the conditioning agent and other
optional ingredients such as perfumes, dyes, etc., in an amalgamator, milled in the
conventional manner under conventional conditions, and extruded into logs for cutting
and stamping into toilet bars. Alternatively, the skin conditioning agent can be co-melted
with the base soap and then cooled to solidify the mixture before introduction into
the amalgamator.
[0039] In making lotions or creams, the conditioning agent is thoroughly mixed with an aqueous
solution or dispersion of the soap.
[0040] Toilet bars of the invention generally comprise from about 10% to about 90% (preferably
from 60% to 90%) soap and from about 1% to about 25% (preferably from about 5% to
about 15%) of the conditioning agents of the invention. Creams generally comprises
from about 10% to about 45% soap and from about 0.5% to about 15% conditioning agent.
[0041] Lotions generally comprises from about 3% to about 15% soap and from about .25% to
about 5% conditioning agent. Creams generally contain from about 50% to about 75%
water, and lotions about 75% to about 95% water.
[0042] The compositions of the invention can be used to prepare articles for cleansing the
skin. These articles can comprise an absorbent paper or woven or nonwoven cloth which
is impregnated with a composition of the invention. For example, a nonwoven cloth
can be impregnated with an aqueous solution of a toilet bar composition of the invention
and then subjected to a drying process which drives off sufficient water to reduce
the moisture content to about 20% or less of the composition thereby producing a cleansing
article which is dry to the touch. Generally the amount of composition on the substrate
should be sufficient to produce a composition:s-ibstrate ratio of about 0.5:1 to 5:1.
When it is used it is simply wetted with water and used in the usual manner of a wash
cloth.
COMPOSITION USE
[0043] The compositions of the present invention are used in the conventional manner of
skin cleansing agents, i.e., they are applied to the skin and then the skin is rinsed
with water. In the case of lotions and creams the composition can be topically applied
"as is" to the skin. In the case of toilet bars, a solution or dispersion of the composition
is formed prior to application by wetting the surface of the bar or rubbing the bar
onto a wet washcloth. The wet bar or the wet washcloth which contains a portion of
the composition is then rubbed against the skin.
[0044] Accordingly, the present invention also includes a method for cleansing and conditioning
of the skin, said method comprising the steps of (1) applying to the skin a composition
of the invention and (2) rinsing the skin with water.
[0045] The invention will be further illustrated by the following examples:
EXAMPLE I
[0046] A toilet bar of the following composition was prepared:

[0047] . 12.94 lbs.of 50/50 tallow/coconut soap noodles (about 85.5% soap, 7% coconut fatty
acid, 7% moisture and 0.5% NaCl) were mixed in an amalgamator with 5 lbs. paraffin
wax, 1 lb. of stearylammonium laurate, 17 grams of a 1% aqueous dye solution, 0.2
lbs, of perfume, 0.614 lbs. of miscellaneous ingredients and 0.340 lbs. water. The
paraffin has been premilled by one pass through a 3-roll soap mill and the stearylammonium
laurate has been preflaked by placing a melt on chill rolls.
[0048] This mixture of ingredients was then passed through the 3-roll soap mill 2 times
at a temperature of 98°F. The resulting flakes were then stored in an airtight container
at 100°F overnight. The next day the flakes were milled a final time at 98°F, plodded
under vacuum and stamped into bar form.
[0049] A panel of 27 women lathered the above bar soap composition (test product) on to
a prewashed terry cloth and each woman washed one half of her face as she normally
would. The product was then spray rinsed off the skin by a 10 second spray of 90-95°F
water. The skin was pat dried with a paper towel. The second half of the face was
then washed in the same manner with a bar of a control product which was made in the
same way as described above but having the following composition:

[0050] The women were then asked which product they preferred for internal skin feel and
external skin feel immediately after drying the skin, and for external skin feel 15
minutes later. Results were as follows:

EXAMPLE II
[0051] A lotion of the present invention is prepared as follows:
1 lb. of the toilet bar composition prepared according to Example I (prior to being
plodded and stamped into bars), along with 0.003 lbs. of xanthan gum, are homogeneously
dispersed into 3 lbs. of water by high shear mixing. The resulting skin cleansing
lotion has the following formula:

EXAMPLE III
[0052] This example illustrates an alternate method of preparing a toilet bar of the present
invention. 11.9 lbs. of 50/50 tallow/coconut sodium soap noodles (81.5%-82.5% soap,
7% coconut fatty acid, 10-11% moisture and 0.5% NaCl) are added to an amalgamator.
0.2 lbs. of perfume and 1.07 lbs. of water and miscellaneous ingredients are then
added and mixing is continued until the batch reaches a homogeneous color (about 5
minutes). The mixture is then transferred to a 3-roll soap mill (operating at about
95%), milled twice and stored overnight in an airtight container at 100°F.
[0053] The following day the stored soap flakes are added to an amalgamator. A co-melt of
5 lbs. of paraffin was (Mobilwax 130 from Mobil Oil Company) and 2 lbs. of stearylammonium
laurate which has been obtained by heating to about 180°F is poured over the soap
flakes while they are being mixed in the amalgamator. Mixing is continued until the
temperature of the mixture drops to about 110°F. The contents are then removed from
the amalgamator and milled twice into flakes, using the 3-roll soap mill operating
at 95°F to 100°F. The milled flakes are held overnight at 100°F and milled a final
time on the 3-roll mill. The milled flakes are then plodded under vacuum (barrel temperature
about 95°F, nozzle temperature about 110°F) and stamped into bars.