Note: Descriptions are shown in the official language in which they were submitted.
W 0 ~2/I66I~ 2 1 ~ ~ ~ ~ PCT/US92/0~8~Z
MILD ~ERSONAL CLEANSING ~ARS WIT~ IMPROVED PROCESSABILITY
CROSS-REFERENCE TO RElATED APPLICATION
This is a continuation-in-part of U.S. Pat. Appln. Ser. No.
07/674,282, filed March 21, 1g91.
TEC~CAL FIELD
This invention relates to personal cleansing bars based on
synthetic surfactants and to processes of making them.
BACKGROUND OF THE INVENTION
"Soap, since its appearance in history, has helped safeguard
two of our greatest treasures: our health and our children.
Health is directly related to cleanliness. Data proves that the
higher the consumption of soap in a country, the lower will be the
infant mortality rate.
"In industrialized countries, soap is the most-taken-for-
granted and readily available personal care product used on our
body daily. Soap is also the most inexpensive product we use in
relation to its per use cost. In many less fortunate countries
both laundry and toilet soaps are still scarce, expensive
essentials. . .
"Soap is most probably the oldest of toiletries, and, in
spite of being readily available in most parts of the world, it is
still scarce in many countries. The oldest literary reference to
soap relates to the washing of wool and is-found in clay Sumerian
tablets dating about 2500 B.C.E. Sumerian was a language spoken
in the area of the Tigris and Euphrates rivers, now Southern Iraq.
The patriarch Abraham and his family came from Sumer. Another
Sumerian tablet, dating 2200 B.C.E. gives the formula consisting
of water, alkali and cassia oil.
"Cleanliness is essential to our well being. A clean body,
clean bath, clean home, and clean environment are the norm today."
(SoaP Technoloqv for the 1990's, L. Spitz et al., American Oil
, . , .- , . . - . . ~ ~. - , ~- .,.
WO 92/~6610 PCl~/US92/00802
2 - ~
Chemists' Society, Champaign, Illinois, pp. 1-2) This reference
discusses syndet and combo bars, particularly on pp. 209-229.
Synthetic surfactant-based personal cleansing bars have
attracted much interest recently because they can be selected to
be milder to the skin than soap-based products. This mildness,
however, comes with negatives to both the manufacturer and the
consumer. The bar soap manufacturer experiences difficult
processability due to the sticky nature of such products, as well
as high raw material costs. The consumer experiences the negative
performance properties of poor lather, messy smear, bar softness,
and, consequently, high wear rates.
The use of paraffin wax in synthetic surfactant-based bars,
per se, is known. However, the known bars suffer from a combi-
nation of harshness and/or lather deficiencies. E.g., U.S. Pat.
No. 2,653,913, van Dijck et al., issued Sept. 29, 1953, discloses
bars comprising 80% synthetic anionic surfactant (selected from
sodium secondary or primary alkyl sulfates or sodium dodecyl-
benzene sulfonate), 18% paraffin, melting point (M.P.) 140-150'F,
and 2% sodium alginate. The surfactants employed are non-mild
surfactants.
U.S. Pat. No. 2,734,870, Lewis, issued Feb. 14, 1956,
discloses bars comprising 40-60% paraffin (M.P. >125F), Z-5%
fatty acid, and 60-40% sodium alkyl aryl sulfonate. The high
level of paraffin ih these bars results in unacceptably low
lather.
U.S. Pat. No. 3,129,187, Meehan, issued Apr. 14, 1964,
discloses bars comprising 50-75% sodium alkylbenzene sulfonate,
5-35% stearyl alcohol, 1-25% paraffin (M.P. 125-170-F), and 2-25%
stearyl MEA. The harsh surfactants employed would result in harsh
products-
U.S. Pat. No. 4,151,105, O'Roark, issued Apr. Z4, 1979,
discloses bars comprising Z0-40% synthetic anionic surfactant
(composed of sodium cocoyl isethionate and/or sodium lauryl
sulfoacetate), 10-30% paraffin (M.P. 130-140~F), S-15% pGwdered
starch, 10-30% dextrin and 5% fatty acid. The low melting point
of the wax employed would cause a substantial soil load on the
lather potential and result in poor lather volumes.
, ~ . . . . . . .. . . . .
w o 92tl6610 2 ~ 3 f~ Pcr/uss2/ooso2
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U.S. Pat. No. 4,335,025, Barker et al., issued June 1~, 1982,
discloses a process for making syndet bars containing a "waxy
extender."
OBJECTS OF THE INVENTION
One object of this invention is to provide a personal cleans-
ing syndet bar composition which exhibits improved lather and
reduced bar messiness, while not sacrificing the processability of
the syndet bar.
SUMMARY OF THE INVENTION
This invention relates to an improved processable, mild
personal cleansing syndet bar comprising: at least about 10% by
weight long chain C1s-C22 alkyl sulfate having essentially satu-
rated, preferably C16-C1g, alkyl chains, soap, free fatty acid, a
lathering mild surfactant comprising C12-C14 alkyl isethionate,
and a selected paraffin wax. The bar has improved bar messiness
without a meaningful lather negative.
DETAILED DESCRIPTION OF THE INVENTION
A mild synthetic surfactant-based (syndet) bar with improved
processability, good lather and/or reduced messiness (smear) is
2~ indeed an advance in this art. The present invention provides
such an improved syndet bar comprising: (1) from about 10% to
about 40%, preferably from about 15% to about 35%, of C1s-C22,
preferably C16-C1g, essentially saturated long chain alkyl sul-
fates; (2) from about 15% to about 40%, preferably from about 18%
to about 35%, of mild, high lathering, synthetic surfactants with
at least about 10% by weight of the bar being C12-C14 alkyl
isethionate; (3) from about 8% to about 25%, preferably from about
10% to about 20%, of C1o-C22, preferably C12-C1g, essentially
saturated fatty acids; (4) from about 2% to about 15%, preferably
from about 3% to about 12%, C10-c22~ preferably C12-C1g, alkali
metal soaps, preferably sodium or potassium soaps; (5) from about
10% to about 40%, preferably from about 13% to about 35%, paraffin
wax with an average melting point of from about 130-F to about
180'f, preferably from about 140-F to about 165F, more preferably
from about 142-F to about 160-F; (6) from 0% to about 10%
auxiliary plastic binders such as polyethylene glycols and/or
monoglyceride; and (7) from about 1.5% to about 10%, preferably
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WO 92/16610 r PCI/US92/00802 g
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from about 2% to about 8%, more preferably from about 2% to about
5/0, water.
While not being bound to any theory, it is advantageous to
think of a synbar as comprising two separate components: the
matrix and the actives. The matrix provides the physical charac-
teristics (processability and bar messiness) while the actives
provide lathering and mild properties. The matrix, if not chosen
correctly, can impede lather generation, cause poor bar fee1,
increase or decrease wear rate beyond an acceptable level, and/or
reduce product mildness. Likewise, the actives must be chosen so
as to provide acceptable levels of lathering without negatively
impacting mildness, a trade-off in formulations.
Bars with improved processability comprising long chain alkyl
sulfate and selected binders are described in commonly assigned,
copending U.S. Patent Applications: Ser. No. 07/605,6I4, J.R.
Schwartz, W.E. Eccard, T.A. Bakken, and L.A. Gilbert, filed Oct.
30, 1990; and Ser. No. 07/647,030, J.R. Schwartz, W.E. Eccard,
T.A. Bakken, and L.A. Gilbert, filed Jan. 28, 1991, incorporated
herein by reference. The present compositions yield bars having
even better product performance in the areas of lather and/or bar
messiness than those specifically exemplified in those patent
applications.
It will be appreciated that the development of an appropriate
bar matrix is a delicate balancing act between plasticity and
brittleness while not compromising lather performance. Typical
bar matrix plasticizer materials such as triglycerides, fatty
alcohols, etc., which tend to form a sufficiently plastic matrix,
but also tend to depress lather potential. Other commonly used
additive matrix materials such as salts, polysaccharides, etc.,
tend to make an overly brittle and water-soluble matrix that
induces poor bar messiness performance.
The terms "synthetic bar," also "syndet bar," as used herein
mean that the "bar" has more synthetic surfactant than soap unless
otherwise specified. The term "AS syndet bar" means a syndet bar
containing alkyl sulfate surfactant or its equivalent, unless
otherwise specified. The term "long chain" means Cls and C22,
preferably C16-C20~ and mixtures thereof. The terms ''C12-Cl4
~ ~: : : .. -. ................. .~ . -
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WO 92/16610 2 1 ~ a ~j PCr/US92/00802
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alkyl" and cocoyl" as used herein are synonymous.
The percentages, ratios, and parts herein are on a total
composition weight basis, unless otherwise specified. All levels
and ranges herein are approximations unless otherwise specified.
An essential element of the present invention is the surfac-
tant system. The long chain alkyl sulfate (hereinafter including
its long chain equivalent synthetic surfactants) is key and is
defined herein, as comprising C16-C1g alkyl chains at a level of
at least about 90/0, preferably about 93%, and more preferably
about 97%. The long chain alkyl sulfate (and its equivalents) is
derived from corresponding saturated straight chain alcohols. The
preferred alkyl sulfate has a ratio of C16-C1g alkyl chains in the
range of from about 100% C16 to about 100% C1g by weight. A
commercially available C16-C1g alkyl sulfate is SIPON~ EC-111
(formerly SIPEX~ EC-111), sodium cetearyl sulfate, which is
approximately 60% C16 and 36% C1g. SIPON~ EC-111 is sold by
Alcolac Company, Baltimore, MD 21226. Another source is Henkel
Corp., Ambler, PA 19002. Henkel's sodium cetearyl sulfate,
LANETTE E, is an estimated 50-50% C16-C1g alkyl sulfate sold as an
emulsifier.
Other long chain surfactants which are equivalents to the
long chain alkyl sulfate (mostly insoluble) could serve as either
full or partial replacements for the long chain alkyl sulfate.
Examples include long chain isethionates, sarcosinates, glyceryl
ether sulfonates, etc. The acyl esters of isethionic acid salts,
with esters of C16-Clg acyl isethionates and no more than 25% or
lower C14 acyl groups are also useful. Preferred is stearoyl
isethioniate with C14 3%; C16 50/0; and C1g 47%.
It is noted that surfactant mildness can be measured by a
skin barrier destruction test which is used to assess the irri-
tancy potential of surfactants. In this test the milder the
surfactant, the lesser the skin barrier is destroyed. Skin
barrier destruction is measured by the relative amount of radio-
labeled water (3H-H20) which passes from the test solution through
the skin epidermis into the physiological buffer contained in the
diffusate chamber. This test is described by T.J. Franz in the
J. Invest. Dermatol., 1975, 64, pp. 190-195; and in U.S. Pat. No.
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4,673,525, Small et al.~ issued June 16, 1987, incorporated herein
by reference, and which disclose a mild alkyl glyceryl ether
sulfonate (AGS) surfactant based synbar comprising a "standard"
alkyl glyceryl ether sulfonate mixture. Barrier destruction
testing surprisingly shows that the long chain alkyl sulfates are
milder than standard AGS. The long chain alkyl sulfate preferably
comprises 15-40% by weight of the bars of this invention.
The present invention contains a mild lathering surfactant at
a level of from about 15% to about 40%, preferably from about 18%
to about 35%. Examples of a high lathering or lather enhancing
surfactant, especially milder ones, are: C12-C14 alkyl isethio-
nate; sodium lauroyl sarcosinate, C12-C14 alkyl glyceryl ether
sulfonate. A "high lathering surfactant" as defined herein, is
one which lathers better than the long chain C16-C1g alkyl
sulfate. A "mild surfactant" as defined herein is one that is
milder than sodium dodecyl sulfate.
Numerous examples of surfactants in qeneral are disclosed in
the patents incorporated herein by reference. They include
limited amounts of anionic acyl sarcosinates, methyl acyl taur-
ates, N-acyl glutamates, acyl isethionates, alkyl sulfosuccinates,
alkyl phosphate esters, ethoxylated alkyl phosphate esters, tride-
ceth sulfates, protein condensates, mixtures of ethoxylated alkyl
sulfates and alkyl amine oxides, betaines, sultaines, and mixtures
thereof. Included in the surfactants are the alkyl ether sulfates
with 1 to 12 ethoxy groups, especially ammonium and sodium lauryl
ether sulfates. Alkyl chains for these other surfactants are
- Cg-C22, preferably Clo-C18. Alkyl glycosides and methyl glucose
esters are preferred mild nonionics which may be mixed with other
mild anionic or amphoteric surfactants in the compositions of this
invention.
The bars of this invention can have up to about 10% of high
lathering, non-mild or shorter chain or traditional (coconut)
alkyl sulfates and still maintain the mildness requirement of the
bar.
A preferred syndet bar contains a mixture of C12-C14 alkyl
isethionate (SCI) and sodium lauroyl sarcosinate in a ratio of
from about 1:1 to about 3:1, preferably from about 1.5:1 to about
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WO 92/16610 ~ r ~ PCT/US92/00802
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2.5 1.
The primary plastic binders of the present invention are: (1)
free fatty acid and (2) paraffin wax.
The fatty acid material which is desirably incorporated into
the present invention includes material ranging in hydrocarbon
chain length of from abut 10 to about 22, essentially saturated.
These fatty acids may be highly purified individual chain lengths
and/or crude mixtures such as those derived from fats and oils.
The preferred composition is lauric and stearic acids in a ratio
10 of from about 1:3 to about 3:1, more preferably from about 1:2 to
about 2.5:1.
The composition may include soaps derived from hydrocarbon
chain lengths of from about 10 to about 22, essentially saturated.
It is preferred that the soap be the sodium salt, but other
15 soluble soap can be used. Potassium, ammonium, triethanolammo-
nium, and mixtures thereof, are deemed acceptable. The soaps are
preferably prepared by the in situ saponification of the corres-
ponding fatty acids, but they may also be introduced as preformed
soaps.
"Insoluble" soaps, e.g., magnesium and zinc soaps, are not
included in the 2-15% level of "soap" in the composition defi-
nition. However, insoluble soaps can be used as non-lathering,
non-soil-load diluents.
An important component of this invention is a wax having a
melting point (M.P.) of from about 130-F to about 180'F (54-
82-C), preferably from about 140'F to about 165-F (60-74-C), and
most preferably from about 142-F to about 160-F (61--71'C). A
preferred paraffin wax is a fully refined petroleum wax which is
odorless and tasteless and meets FDA re~uirements for use as
coatings for food and food packages. Such paraffins are readily
available commercially. A very suitable paraffin can be obtained,
for example, from The National Wax Co. under the trade name 6975.
The paraffin preferably is present in the bar in an amount
ranging from about 10% to about 40% by weight. The paraffin
ingredient is used in the product to impart skin mildness, plas-
ticity, firmness, and processability. It also provides a glossy
look and smooth feel to the bar.
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PCT/US9t/0080Z
The para~fin ingredient is optionally supplemented by a
microcrystalline wax. A suitable microcrystalline wax has a
melting point ranging, for example, from about 140'F (60~C) to
about 185-F (85-C), preferably from about 145-F (~2-C) to about
175-F (79 C). The wax preferably should mcet the FDA requirements
for food grade microcrystalline waxes. A very suitable micro-
crystalline wax is obtained from Witco Chemical Company under the
trade name Multiwax X-145A. The microcrystalline wax preferably
is present in the bar in an amount ranging from about 0.5% to
about 5% by weight. The microcrystalline wax ingredient imparts
pliability to the bar at room temperatures.
Auxiliary plastic binders may be incorporated into the bar at
levels of from 0% to about 10%. ~hese binders may be selected
from monoglycerides, polyethylene glycols, fatty alcohols, sugars, `
lS tallow alcohol ethoxylates, and mixtures thereof. Other plastic
binders are identified in the published literature, such as J.
Amer. Oil Chem. Soc. 1982, S9, 442. The binder system can contain
several plasticizers.
The syndet bar of this invention may comprise 0% to about 5%
of a suitably fast hydrating cationic polymer. The polymers have
molecular weights of from about 1000 to about 3,000,000.
The cationic polymer (skin conditioning agent) is selected
from the group consisting of:
(I) cationic polysaccharides;
25 (II) cationic copolymers of saccharides and synthetic
cationic monomers, and
(III) synthetic polymers selected from the group consisting
of:
(A) cationic polyakylene imines ~ -
(B) cationic ethoxy polyalkylene imines, and
(C) cationic poly[N-[-3-(dimethylammonio)propyl]-N'-[3-
(ethyleneoxyethylene dimethylammonio)propyl]urea
dichloride].
Specific examples of members of the cationic polysaccharide
class include the cationic hydroxyethyl cellulose JR 400 made by
Union Carbide Corporation; the cationic starches Stalok~ 100, 200.
300 and 400 made by Sta1ey, Inc.i the cationic galactomannans
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WO ~2/16620 PCI/US92/00802
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based on guar gum of the Galactasol 800 series by Henkel, Inc.,
and the Jaguar series by Celanese Corporation.
Examples of members of the class of copolymers of saccharides
and synthetic cationic monomers include those composed of cel-
5 lulose derivatives (e.g., hydroxyethyl cellulose) and N,N-di-
allyl~N-N-dial~yl ammonium chloride available from National Starch
Corporation under the trade name Celquat.
The cationic synthetic polymers useful in the present in-
vention are cationic polyalkylene imines, eth~xypolya1kylene
10 imines, and poly[N-[-3-(dimethy1ammonio~propyl]-N'-[3-(ethylene-
oxyethylene dimethylammonio)propyl]urea dichloride] the latter of
which is available from Miranol Chemical Company, Inc., under the
trademark of Miranol A-15, CAS Reg. No. 68555-36-2.
Preferred cationic polymeric skin conditioning agents of the
15 present invention are those cationic polysaccharides of the
cationic guar gum class with molecular weights of 1,000 to
3,000,000. More preferred molecular weights are from 2,500 to
350,000. These polymers have a polysaccharide backbone comprised
of galactomannan units and a degree of cationic substitution
20 ranging from about 0.04 per anhydroglucose unit to about 0.80 per
anhydroglucose unit with the substituent cationic group being the
adduct of 2,3-epoxypropyltrimethyl ammonium chloride to the
natural polysaccharide backbone. Examples are JAGUAR C-14-S, C-l5
and C-17 sold by Celanese Corporation. In order to achieve the
25 benefits described in this invention, the polymer must have
characteristics, either structural or physical which allow it to
be suitably and fully hydrated and subsequently well incorporated
into the soap matrix.
Other ingredients of the present invention are selected for
30 the various applications. E.g., perfumes can be used in formu-
lating the skin cleansing products, generally at a level of from
about 0.1% to about 1.5% of the composition. Alcohols, hydro-
tropes, colorants, and fillers such as talc, clay, calcium car-
bonate and dextrin can also be used. Cetearyl alcohol is a
35 mixture of cetyl and stearyl alcohols. Preservatives, e.g.,
sodium ethylenediaminetetraacetate (EDTA), generally at a level of
less than 1% of the composition, can be incorporated in the
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WO 92~16610 PCI/US92/008~2
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cleansing products to prevent color and odor degradation. Anti-
bacterials can also be incorporated, usually at levels up to 1.5%.
The following patents disclose or refer to such ingredients and
formulations which can be used in the soap/synbars of this inven-
5 tion, and are incorporated herein by reference:
Pat. No.Issue Date Inventor(s)
4,234,46411/1980 Morshauser
4,061,60212/1977 Oberstar et al
4,472,2979/1984 Bolich et al.
4,491,5391/1985 Hoskins et al.
4,540,5079/1985 Grollier
4,673,5256/1987 Small et al.
4,704,22411/1g87 Saud
4,812,2533/1989 Small et al.
4,820,4474/1989 Medcalf et al.
4,954,2829/1990 Rys et al. ~
' ~;
The syndet bars of this invention have a pH of from 4 to 9 in
a 1% aqueous solution. The preferred pH is from 5 to 8, more
preferably about 6.5 to 7.5.
Matrix Ratio Table
A matrix of ratios and key ingredients of the present inven-
tion is provided in following table. The Matrix Ratio Table shows
the broad, preferred and more preferred levels and ratios of the
several key ingredients. E.g., the bars of the present invention
; can have long chain alkyl sulfate at a level of 10-40% by weight
of the bar and lathering mild synthetic surfactant at a level of
15-40% by weight of the bar. Their broad and preferred ratio
ranges are, respectively, 2.5:1-0.3:1 and 2:1-0.4:1. Their more
preferred and exemplified ratios are found in Examples 6 and 7 and
are, respectively, 0.6:1/0.5:1. Another example of a reading of
the Matrix Ratio Table is the lathering mild synthetic surfactant
and paraffin which, respectively, have broad and preferred ratios
of 4:1-0.4:1 and 2.5:1-0.5:1. In Examples 6 and 7, their ratios
, 35 are, respectively, 1.7:1 and 0.9:1.
: The percentages, ratios, and parts herein are on a total
.
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WO 92/16610 ~ Ij PCr/USg2/00~302
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composition weight basis, unless otherwise specified. All levels
and rang~s herein are approximations unless otherwise specified.
MATRIX RATI0 TABLE
Lathering
Mild Synthetic
Surfactant Fattv Acids SoaPs Paraffin
Lonq Chain
(C16-18~
AlkYl Sulfate
Broad: 10-40%2.5:1-0.3:1 5:1-0.4:1 20:1-0.7:14:1-0.3:1
Preferred:
15-35%2:1-0.4:1 3.5:1-0.8:1 12:1-1:12.5:1-0.4:1
Form. 6/Form. 7 0.6:1/0.5:1 1 .5: 1/1.S:14:1/3.B:1 1: 1/0.9:1
Latherinq
Mild Synthetic
Surfactant
Broad: 15-40%N/A 5:1-0.6:1 20:1-1:14:1-0.4:1
Preferred: 18-35%N/A3.5:1-0.9:1 12:1-1.5:12.5:1-0.5:1
Form. 6/Form. 7 N/A2.8:1/2.8:1 7.2:1/7.4:11.7:1/1.8:1
Free FattY Acids
Broad: 8-25% * N/A 12.5:1-0.5:12.5:1-0.2:1
Preferred: 10-20% * N/A 7.1-0.8:11.5:1-0.3:1
Form. 6/Form. 7 * N/A 2.6:1/2.6:10.6:1/0.6:1
Broad: 2-15% * * N/A1.5:1-0.05:1
Preferred: 3-12% * * N/A 1:1-0.08:1
Form. 6/Form. 7 * * N/A0.2:1/0.2:1
Paraffin Wax
Broad: 10-40% * * * N/A
Preferred: 13-35% * * * N/A
Form. 6/Form. 7 * * * N/A
*Sho~n elsewhere in the Table.
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LaboratorY Ass~ssment of Bar
The following test procedures are used to evaluate the
critical bar performance attributes of mildness and bar processa- , -
bility.
Smear Test Procedure
Equipment: ,
l. #2-202C Fisher Brand Hexagonal Polystyrene weighing dishes
(4 x 3 ).
2. #14-366A Fisher Brand Spatula.
3. Balance capable of weighing to two decimal points.
4. 120-F Temperature Room.
5. Timer.
M~k~g
1. Label and weigh the number of weighing dishes needed (two
weighing dishes per sample, one labeled M for mush dish, one
labeled S for soak dish).
2. Weigh the original bar and record the weight. Place bar in
preweighed dish labeled S.
3. Add 30 mls room temperature city water to the dish containing
the bar prototype (pour water down side of weighing dish).
Add 30 mls room temperature city water to the dish containing
the control bar. When placing the bars in the dish make sure
the bars are not touching the sides of the dishes.
4. Allow bars to soak in weighing dishes at room temperature for
2 hours undisturbed.
5. After 2 hours of soaking, pick bar up carefully and allow to
drain into the same dish for 15 seconds.
6. After 15 seconds, invert bar and place in preweighed dish
labeled M.
7. Weigh soaked bar and record.
8. Scrape the wet surface or mush from the bar, with a spatula,
into the same preweighed dish labeled M, weigh and record,
this is the "wet" smear grade. Best results for scraping are
seen when the spatula is held loose in hand being careful not
to gouge the bar or to scrape too deeply. When the surface
of the bar no longer appears to look wet or shiny, scraping
is completed. To eliminate variability of scraping from
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WO 92/16610 PC~US92/OOX02
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person to person, results from each test will be reported
relative to the control placed in that test.
9. Weigh and record the scraped bar.
10. Place the soak dish, the mush dish, and the scraped bar in
the 120-F Temperature Room ~or water evaporation for 48
hours.
Il. After 48 hours, weigh and record the dry weight of the soak
dish, the mush dish and the scraped bar.
12. Calculate the surface area of the scraped portion of the bar
by measuring (in inches) length times width.
13. Add the number of dry grams of mush (smear) to the number of
dry grams of soak. This is the "dry" smear grade in grams.
All series of testing should include control, and all samp1es
should be run in duplicates. A maximum of 7 products (6 plus a
control) can be tested at one time, and an interval of 10 minutes
between every 4 samples should be allotted for the addition of
water as to not allow any products a lag time for soaking longer
than 2 hours.
Bar Soap Handwash lather Volume Test
The handwash lather test is used to provide in-use lather
volume measurements for the lather performance of skin cleansing
bars. The test measures both the ultimate lather volume generated
and the volume which is generated after a very short lathering
period (to reflect lathering ease). The lather volumes are
generated under soil-loaded conditions.
Synthetic soil is used for the soil-loaded lather volume test
reported herein. Its formula and procedure for making it are set
out below.
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TABlE 1
Svnthetic Soil
Inqredients Wt. %
Hyfac 430a 1.~7
lauric Acidb 1.42
Neo-fat 14C 5.68
Neo-fat 16d 11.16
Neo-fat 18e 5.40
Neo-fat 90-04f 9.81
Industrene 2269 1.26
Paraffin Wax 7.30
Squalaneh 3.70
Lanolin Anhydrous 19.40
Coconut Oil 3.30
Tallow 29.70
100.00%
a Emery Industries, Inc., Cincinnati, Ohio
b Emery Industries, Inc., Cincinnati, Ohio
c Armour Industrial Chemical Co., Chicago, Illinois
d Armour Industrial Chemical Co., Chicago, Illinois
e Armour Industrial Chemical Co., Chicago, Illinois
f Armour Industrial Chemical Co., Chicago, Illinois
9 Humko Products, Memphis, Tennessee
h Robeco Chemicals, Inc., New York, New York
Procedure
1. Heat above materials together stirring continuously between
160-175-F.
2. Mix 25 parts of above formula with 25 parts of a 5% to 80%
tallow/20% coconut soap solution and 50 parts of distilled
water at 150-F.
3. Cool mixture to room temperature while stirring constantly.
4. Store in covered glass container.
EquiDment
The following equipment is used:
1. Water source and sink with temperature control. The water
source should be medium hardness (6-9 grain/gallon) for
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most testing, although water of lower and higher hardness
can be used for special purposes.
2. Synthetic soil (see Table 1).
3. Paper towels.
4. Test bars.
5. Control bars.
Procedure
The following procedure is used:
1. Set temperature at 95-100-F.
2. Rub 0.22 cc of soil on hands.
3. Wet hands.
4. Rotate bar 3 times in both hands.
5. Add a little water, rub both hands 5 times.
6. Rotate hands 3 times (without soap), grade for flash volume.
7. Rotate 7 more times, grade for ultimate volume.
8. Collect lather and deposit on sink top.
9. Compare volume with standard bar target volume and assign
grade.
Grading Scale
Soil Loaded
7 - Exceptional
6 - Very much higher than target
S - Higher than target
4 - Target volume
3 - Slightly lower than target
2 - Lower than target
In Vitro Skin Barrier Penetration Test (Mildness!
This test was performed according to the procedure described
in U.S. Pat. No. 4~812,253, Small et al., issued Mar. 14, 1989,
said patent incorporated herein by reference.
Frequently, materials which tend to improve processability
also tend to have other negatives, particularly in terms of
product mildness. Referring to Table 2, using the barrier
destruction method to assess product mildness, individual raw
materials sodium cetearyl sulfate is shown to be surprisingly more
mild than the ultra mild sodium cocoglycerylether sulfonate, as
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well as a shorter chained AS, sodium dodecyl sulfate. The lower
the number in ~able 2 the milder the product.
TABL~ 2
Mg 3H20 TransDorted
Water 0.137
Sodium Cetearyl Sulfate 0.302
Sodium Cocoglycerylether Sulfonate 0.458
Sodium Dodecyl Sulfate 1.289
Sodium Laurate 1.805
A Method of Makinq SYndet Bars
Crutchin~
1. Add melted sodium cetearyl sulfate to the crutcher.
2. Add predetermined quantity of Hamposyl L-30 solution to
the crutcher mix.
3. Add the predetermined quantity of AGS paste to the water
in the crutcher. The AGS paste can be at ambient
temperature or preheated to 150-F (65C).
4. Turn on the agitator and recirculation pump and maintain
temperature in crutcher at 130-150F (54-65'C) by
adjusting steam and water valves.
5. Allow contents in crutcher mix to return to 130-150F
(54-65'C) prior to adding predetermined quantity of
stearic acid.
6. Add to heated crutcher mix predetermined quantity of
soap or NaOH to form in-situ soap.
7. Allow the contents in the crutcher to mix and/or react
for about 15 minutes while maintaining the temperature
at 130-150F (54-65C).
8. Add sodium chloride plasticizer and titanium dioxide to
the heated crutcher mix.
9. Add lauric and/or coconut fatty acids to crutcher mix
and allow contents of crutcher to mix for about 15
minutes while maintaining temperature at 130-150F
(54-65'C).
10. Add paraffin wax in a molten form and allow crutcher to
mix approximately 1/2 hour until uniform.
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DrYi nq
The crutcher mix is dried and cooled using a combination
flash chamber and chill roll or chill belt. The crutcher mix is
first heated to approximately 300-F (149-C) by a heat exchanger
and then flash dried in a chamber above the chill roll or chill
belt. From the flash chamber the hot, dried mix is extruded onto
the chill roll or chill belt. The chill belt or chill roll
provides a uniform, thin, cool (85-95'F, 29-35-C) product in flake
or chip form. Typical moisture for the flake is 1-10%, preferably
about 2-4.5%. The ways to regulate the moisture, in the order of
preference, are (1) increasing or decreasing steam pressure on the
heat exchanger; (2) increasing or decreasing crutcher mix rate to
the heat exchanger; and (3) increasing or decreasing crutcher mix
temperature to the heat exchanger.
Amalqamatinq
The flakes are weighed and mixed in a batch amalgamator to
obtain uniform flake size. Preweighed perfume is added to the
flakes and mixed in the amalgamator to obtain the desired finished
product perfume level. The perfumed flakes are transferred to the
mix hopper or directly to the plodd2r.
Milling
The 3-roll soap mills are set up with the first roll at 120F
(49C) and the other two mills at about 44F (7-C). The material
is passed through the mills several times to provide a homogeneous
mixture of perfume and dried flakes.
Ploddina and Stampinq
The plodder is set up with the barrel temperature at about
115'F (46C) and the nose temperature at 114-122-F (45-SO'C). The
ideal plodder is a dual stage plodder that allows use of a vacuum
of about 15-25 inches of Hg. The plugs should be cut in 5"
sections and stamped with a cold die block using die liquor such
as alcohol, if appropriate.
EXAMPLES AND FORMULAS
The following formulas and examples are illustrative and are
not intended to limit the scope of the invention(s). The methods
of making milled bars are well known. All levels and ranges,
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temperatures, results etc., used herein are approximations unless
otherwise specified. The bars of this invention in the Formulas
and Examples all have a pH of about 7 to about 7.5.
The level of the water in the above syndet bars stabilizes
upon storage from about 3.75% to about 2%-3%.
COMPARATIVE EXPERIMENTAl FORMULA A
Comparative Experimental Formula A is the control bar for
assessing father and/or smear of the bar of this invention.
Comparative Formula A is typical of an alkyl sulfate-based product
disclosed in commonly assigned, copending U.S. Pat. Application
Ser. No. 07/605,614, supra. Formulas 1 through 7 described below
have improved smears compared to Comparative Formula A, without
sacrificing processability. In some cases of Formulas 1 through
7, the lather volume has been reduced, these are included to teach
the scope of the patent. Acceptable soil lather grades are those
that are of magnitude 3.0 or greater.
FORMULAS 1-3
Formula 1 demonstrates the large improvement in smear (lower
numbers) upon incorporation of 21% paraffin wax relative to
Comparative Formula A. See bottom of Table 3. Formulas 1-3
demonstrate the surprising benefit that paraffin waxes can impart
to syndet bars containing long chain alkyl sulfates. Formula 2
further demonstrates that paraffin wax of a higher melting point
(155-F/69-C) than that used in Formula 1 still provides an
improved smear but without the large detriment to lather that the
lower melting point (135'F/59-C) paraffin imparted to Formula 1.
Formula 3 contains a mixture of the two paraffins which demon-
strate intermediate properties between Formulas 1 and 2.
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TABLE 3
Comp
Form. A Form. 1 Form. 2 Form.v3
Inqredient (Wt.%) (Wt.%) (Wt.%)(Wt.%)
Sodium Cetearyl
Sulfate 30.5 20.0 20.0 20.0
Sodium Lauroyl
Sarcosinate 12.0 12.0 12.0 12.0
Sodium Cocoglyceryl-
ether Sulfonate16.0 20.0 20.0 20.0
Sodium Soap
(in situ) 7.5 5.0 5.0 5.0
Stearic Acid 13.0 8.7 8.7 8.7
Lauric Acid 6.0 4.3 4.3 4.3
Paraffin (M.P.
~135F/59-C) - 21.0 - 6.0
Paraffin (M.P.
~155-F/69-C) - - 21.0 15.0
PEG-150 10.0 4.0 4.0 4.0
Perfume 1.0 1.0 1.0 1.0
Titanium Dioxide0.25 0.25 0.25 0.25
Water 3.75 3.75 3.75 3.75
Performance Data:
Avg. Soil Lather 4.4 0.5 3.0 2.8
Smear, Wet 4.3 1.8 3.8 2.5
Smear, Dry 2.2 1.1 1.7 1.5 ~ .
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Inqredient Form. 4 Form. 5 Form. 6 Form._7
(Wt.%) (Wt.%) (Wt.%) (Wt.%)
Sodium Cetearyl
Sulfate 20.0 20.0 20.0 19.0
Sodium Lauroyl
Sarcosinate 12.0 12.0 12.0 13.0
Sodium Cocoglyceryl-
ether Sulfonate24.0 20.0 24.0 24.0
Sodium Soap
(in situ) 5.0 5.0 5.0 5.0
Stearic Acid 8.7 4.3 4.3 4.3
Lauric Acid 4.3 8.7 8.7 8.7
Paraffin (M.P.
-135-F/59-C)
Paraffin (M.P.
-155-F/69-C) 21.0 21.0 21.0 21.0
PEG-150 - 4.0
Perfume 1.0 1.0 1.0 1.0
Titanium Dioxide 0.25 0.25 0.25 0.25
Water 3.75 3.75 3.75 3.75
Performance Data:
Avg. Soil Lather 3.0 3.0 3.5 4.0
Smear, Wet 3.3 3.1 2.3 3.2
Smear, Dry 1.6 1.5 1.3 1.6
FORMULAS 4-6
Formulas 4 through 6 demonstrate the effects of auxiliary
plasticizers such as polyethylene glycol (PEG) on the paraffin-
containing long chain alkyl sulfate matrix. Formula 4 has lower
(better) smear (3.3/1.6 vs. 3.8/1.7) than Formula 2, the dif-
ference being the presence of PEG in Formula 2. This smear
improvement is achieved with no detriment to lather volume
(3.0/3.0). Formulas 5 and 6 differ in a similar way: Formula 6
(no PEG) has better smear than Formula 5; surprisingly, Formula 6
actually has improved lather as well.
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Formula 7 demonstrates that lather can further be improved by
increasing the level of high lathering synthetic surfactants
(Form. 6 with 12% vs. Form. 7 with 13%), such as sodium lauroyl
sarcosinate, surprisingly without substantially harming smear
(Form. 6 with 3.5 lather vs. Form. 7 with 4.0 lather, and Form. 6
with smears of 2.3 and 1.3 vs. Form. 7 with smears of 3.2 and
1.6).
Both Formulas 6 and 7 are highly preferred syndet bars which
have very good lathers and improved smears while still being
highly processable.
EXAMPLE I
Example I is a highly preferred personal cleansing bar of the
present invention. It is the same as Formula 6, except that
sodium cocoyl isethionate (SCI) is used in place of sodium coco-
glycerylether sulfonate (AGS).
EXAMPLES II and III
Example II is similar to Example I, but 5% less cocoyl
isethionate is used and 5% sodium isethionate is used. Example
III is also similar to Example I, but a mixture of lauric and
coconut fatty acids is used, and less lauric acid is used.
Advantaqes
Examples I-III retain all of the advantages of Formula 6, but
replacing the AGS with SCI results in a bar with substantially
improved processability. Specifically, the product is a little
softer during extrusion, flakes are more friable, and the product
(bar) is slightly less sticky. The next of these differences is
improved processability and an improved personal cleansing bar.
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TABlE 4
~ EX. III
Inaredient (Wt.%) (Wt.%) (Wt.%)
Sodium Cetearyl Sulfate 20.0 20.0 20.0
Sodium Lauroyl
Sarcosinate 12.0 12.0 12.0
Sodium Cocoyl Isethionate 24.0 19.0 24.0
Sodium Isethionate - 5.0
Sodium Soap (in situ~ 5.0 5.0 S.0
Stearic Acid 4.3 4.3 4.3 .
Lauric Acid 8.7 8.7 8.7
Coconut Fatty Acid - - 3.0
Paraffin (M.P.
-155F/69'C) 21.0 21.0 21.0
Perfume 1.0 1.0 1.0
Titanium Dioxide 0.25 0.25 0.25
Water 3.75 3.75 3.75
Performance Data:
Avg. Soil Lather 3.3 N/A N/A
Smear, Wet 3.2 N/A N/A
Smear, Dry 1.9 N/A N/A
WHAT IS CLAIMED IS:
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