Adjuvant composition

The present invention relates to novel chip compositions containing specific polyol ester as the major carrier for liquid skin benefit agents. Addition of specific polyol esters wherein the melting temperature and HLB are specifically defined has been found to remarkably enhance the oil/humectant structuring capability of a skin cleansing bar. Such a polyol ester also permits the liquid benefit agents to be released into a personal wash liquor and then to be delivered to skin via personal wash. In a second embodiment, the invention relates to a method for enhancing the bar's capability of including high levels of oil and/or humectant by applying the adjuvant technology. That is, by coextruding and stamping the mixture of chips containing skin benefit agents and base chips containing a surfactant system, high levels of oils and/or humectants can be incorporated into solid toilet bars by standard extrusion technology. In the third embodiment, skin mildness and especially skin moisturization are significantly enhanced by the detergent bar compositions comprising the combination of the specific polyol ester with oil and/or humectant.

FIELD OF THE INVENTION 
The present invention relates to personal wash bar compositions, 
particularly compositions comprising (1) one or more surfactants, (2) one 
or more liquid emollient oils and/or humectants, and (3) a solid polyol 
ester with specifically defined HLB and melting temperature. In 
particular, the invention relates to chip compositions comprising 
emollient droplets entrapped and/or dissolved in a specific solid polyol 
ester as the thickened carrier. The emollient containing thickened carrier 
compositions are formed as separate chip/powder/granule compositions 
(referred herein as adjuvant chips) and are then mixed with "base" chips 
(comprising the surfactant system) prior to milling, extruding and 
stamping the bars. Through careful balancing of the polyol ester to oil 
and/or humectant ratio in the adjuvant chips, a novel approach of 
delivering mild, moisturizing ingredients to the skin via personal wash 
bar is developed. The invention relates to a method of making the 
additives. The invention further relates to a method of enhancing delivery 
of benefit agents from bars which method comprises mixing the base chips 
with the benefit agent containing adjuvant chips, milling, extruding and 
stamping. 
BACKGROUND 
It is technically difficult to include high levels (e.g., 10-20%) of liquid 
hydrophobic emollient oil (e.g., sunflower seed oil) and/or hydrophilic 
liquid humectant (e.g., glycerin) in the form of a solid personal washing 
bar and meanwhile maintain the bar mildness and benefit delivery to the 
human skin. 
For example, high levels of humectants (e.g., glycerin, low MW polyalkylene 
glycol) can be trapped in a solid matrix of caboxylic fatty acid soap. 
However, it is known that carboxylic soap is harsh to skin especially when 
the soap concentration is high and when the soap is dissolved in the 
aqueous washing liquor through its own hydrophilic tendency or through the 
acts of cosurfactants in the bar. 
On the other hand, non-soap synthetic bar formulations are primarily 
structured by either hydrophobic crystalline materials such as free fatty 
acid or paraffin wax or by hydrophilic crystalline materials such as 
polyalkylene glycol of high molecular weight (e.g., MW between 2000 and 
20000). 
Not to be bound by the theory, formulating high levels of emollient oil 
into the hydrophobic crystalline materials is believed to result in 
tightly binding the oil with the hydrophobic crystalline structurants. 
This contributes to the incapability of releasing the oil to water from 
the bar and may prevent delivering oil to skin via personal wash (see 
Example 1). 
Including liquid oils and/or liquid humectants in bars structured by 
hydrophilic crystalline materials leads to another difficulty. That is, 
the oil and the humectant are not compatible with the hydrophilic 
structurants such as PEG 8000, and this incompatibility results in oil 
leakage and phase separation from the bulk portion of the bar solid (see 
Example 1). 
Therefore, a novel mild bar structuring system is required to be able to 
satisfactorily structure the oil and/or the humectant in the bar solid 
while simultaneously permitting oil release from the bar to the aqueous 
liquid and then to the human skin via the route of personal wash. 
Novel to the art, the applicants of the subject invention found a specific 
group of polyol esters (i.e., having specific ranges of HLB and specific 
melting temperature) are capable of both structuring a high level of 
hydrophobic emollient oils and/or humectants in solid form while still 
permitting the oil and humectants to be released from the solid into 
aqueous liquor to be delivered to the human skin through the route of 
personal wash. Balancing the ratio between polyol ester and oil/humectant 
are critical to achieve the desired oil structuring and oil releasing. The 
polyol ester solids containing high level of emollients/humectants can be 
processed into the form of soft solid chips, flakes or powders and then 
mixed with "base" chips (comprising the surfactant system) prior to 
milling, extruding and stamping the bars. This specific way of processing 
the bars is referred herein as the "adjuvant technology". Using the said 
specific polyol esters to incorporate high levels of emollients/humectants 
in the adjuvant chips that are then mixed with the base chips results in 
novel bar formulations, which are able to deliver high dosage of benefit 
agents to skin via personal wash and provide satisfactory bar user 
properties such as cream and/or lotion-like lather even in the presence of 
high oil levels. The presence of high levels of oil and/or humectant in 
bar made by said adjuvant technology also effectively reduces the skin 
irritation potential of surfactants. 
The use of polyol esters in personal washing bars is not new. 
European Patent Application EP 94105052.8 assigned to Kao Corp. (invented 
by M. Tonomura and T. Ohtomo), for example, teaches the use of 
monoglyceridesto boost the lather of formulations comprising only nonionic 
surfactants. The application does not teach the use of the combination of 
specific solid monoglycerides and high level of liquid emollient 
oils/humectants to make bars, preferably pourable, cast melt bars, 
preferably comprising anionic surfactants and amphoteric surfactants. It 
does not teach the use of "adjuvant technology" to make high 
emollient/humectantcontaining bars in general. By contrast, the subject 
invention found that by using a specific polyol ester (e.g., specific 
range of HLB, polyol ester to oil/humectant ratio), high levels of 
emollient oil and/or humectants can be satisfactorily incorporated into 
adjuvant chips and then mixed with the "base chips" through the adjuvant 
technology. 
An international application published under PCT WO 92/13060 to Procter & 
Gamble (authored by R. James) teaches the use of monoglycerides in 
general, PEG and fatty acid as binders for an extruded syndet bar 
formulation. The prior art, however, does not teach the use of a specific 
combination of specific monoglycerides (e.g., specific ranges of HLB) and 
PEG and fatty acid to incorporate high level of liquid emollients (e.g., 
vegetable oils)/liquid humectants (e.g., glycerin) to make a bar. The 
prior art also does not teach the specific bar formulation spaces to 
ensure that high levels of liquid oils and/or humectants can be structured 
in the solid bar matrixes and can be delivered to skin via personal wash. 
In contrast, the subject invention uses the adjuvant technology to prepare 
chips containing high levels of oils and/or humectants. By using a 
specific polyol ester (e.g., polyol esters with specific range of HLB, 
specific polyol ester to oil ratio, and specific polyol ester to other 
structurant (e.g., PEG and fatty acid) ratio), high levels of emollient 
oil and/or humectants can be satisfactorily incorporated into adjuvant 
chips and then into bars and can be delivered from the bars to skin under 
the personal wash condition. 
U.S. Pat. No. 5,510,050 to J. Dunbar, P. Beerse, and E. Walker also teaches 
the use of monoglycerides in general as a non-preferred candidate for the 
plasticizers in an extruded cleansing bar containing liquid polyols 
(4-15%) and magnesium soap (4.5 to 50%). The preferred plasticizers are 
fatty acids, sodium soap, and paraffin wax (Column 5, line 22-24). The 
prior art, however, does not teach the use of a specific combination of 
specific monoglycerides (e.g., specific ranges of HLB) and other 
plasticizers to incorporate high level of liquid emollients (e.g., 
vegetable oils)/liquid humectants (e.g., glycerin) into a bar. The prior 
art also does not teach the specific bar formulation spaces to ensure that 
high levels of liquid oils and/or humectants can be structured in the 
solid bar matrixes and can be delivered to skin via personal wash. In 
fact, as found by the subject invention, the preferred plasticizers used 
in the prior art hinder the skin deposition of liquid oils from bars to 
skin. The prior art has to use magnesium soap as the key ingredient to aid 
processing (column 2, line 26). In contrast, the subject invention uses 
the adjuvant technology to prepare solid chips containing high levels of 
oils and/or humectants. By using a specific polyol ester (e.g., polyol 
esters with specific range of HLB, specific polyol ester to oil ratio, and 
specific polyol ester to other structurant (e.g., PEG and fatty acid) 
ratio), high levels of emollient oil and/or liquid humectants can be 
satisfactorily incorporated into chips and then into bars and can be 
delivered from the bars to skin under the personal wash condition. In the 
subject invention, carboxylic acid soap is not included in the chip 
composition and is an optional ingredient of the total bar composition. 
A Great Britain Patent GB 1,570,142 assigned to GAF Corp. teaches the use 
of both hardened triglycerides and fatty alcohols as the plasticizers in 
an extruded syndet formulation. In contrast to the subject invention, the 
application does not teach the use of the combination of specific 
monoglycerides and high level of liquid emollient/humectants to make bars. 
It does not teach the use of adjuvant technology to make high 
emollient/humectant containing bars in general. By contrast, the subject 
invention found that by using a specific polyol ester (e.g., specific 
range of HLB, polyol ester to oil ratio, and polyol ester to other 
structurant ratio), high levels of emollient oil and humectants can be 
satisfactorily incorporated in the bar for the skin benefit through the 
adjuvant technology. 
The art of using the adjuvant technology to incorporate emollients into 
bars is not new. 
U.S. Pat. No. 5,154,849 to Visscher et al. teaches bar compositions 
containing a silicone skin mildness/moisturizing aid component. In one 
embodiment, the silicone component may be mixed with a carrier which is 
selected to facilitate incorporation of the silicone. At column 16, the 
reference describes that silicone is mixed into melted Carbowax (i.e., 
polyethylene glycol), that the mixture is cooled to form flakes, and that 
the flakes are preferably added to an amalgamator. 
It is clear, however, that the Visscher et al. contemplates a 
silicone/carrier system different from the adjuvant chips of the subject 
invention. First, the Visscher patent does not teach selecting a carrier 
having specific HLB to both carry high levels of oils and permit oil 
release from the solid into water. For example, polyethylene glycol 
(HLB&gt;18) is not miscible with most of hydrophobic oils such as silicone 
oil or vegetable oil at mixing temperatures (e.g., 70-120.degree. C.), and 
upon cooling, oil tends to leak out of the PEG solid matrix. Therefore PEG 
has a poor oil-carrying capacity although it permits oil release from oil 
into water and then to skin via personal wash (see Example 1). On the 
other hand, fatty acid, ethers, alcohols or paraffin wax (HLB&lt;2) have high 
oil carrying capability (Example 1); however, it is difficult to have oils 
released from those hydrophobic solids into water and then to skin at 
conditions relevant to personal wash. Novel to the art, subject invention 
found that specific solid polyol esters (i.e., specific HLB between 2.5 
and 15) are capable of carrying high levels of oil/humectant and 
simultaneously providing oil release from the solid into water then to 
skin via personal wash. 
U.S. Patent applications filed by Unilever (95-R385-EDG and 95-R385-B-EDG) 
use additional thickeners such as fumed silica or additional 
hydrophobically modified polyalkylene glycols or EO-PO copolymers to 
improve the oil-carrying capability of polyalkylene glycol in the adjuvant 
chips and to modify the dissolution speed of the adjuvant chips in water. 
Nevertheless, those applications use highly hydrophilic materials such as 
PEG and EO-PO (HLB&gt;&gt;15) and do not teach selecting a carrier having 
specific HLB (between 2.5 and 15, preferably between 2 and 8) to not only 
carry high levels of oils but also permit oil release from the solid into 
water. For example, polyethylene glycol (HLB&gt;18) or hydrophobically 
modified PEG claimed (HLB&gt;15) are not miscible with most of hydrophobic 
oils such as silicone oil or vegetable oil at mixing temperatures (e.g., 
70-120.degree. C.), and, upon cooling, oil tends to leak out of the solid 
matrix (see Example 1). Thus thickeners such as fumed silica have to be 
added to improve the adjuvant's oil-carrying capacity. Nevertheless, fumed 
silica is in the form of very fine powders (i.e., 7-30 millimicrons), 
which increase the processing difficulties and potentially increase the 
cost. By contrast, subject invention teach the use of specific solid 
polyol esters (i.e., specific HLB between 2.5 and 15) to carry high levels 
of oil/humectant and provide oil release from the solid into water then to 
skin via personal wash without or with a reduced level of thickeners such 
as fumed silica (e.g., 0-0.5%), which is advantageous because potentially 
processing can be simplified and cost can be reduced. 
In summary, none of the references, alone or in combination teach that the 
use of specific polyol esters (e.g., having specific melting temperature, 
especially specific hydrophobic-lipophobic balance (HLB)) in specific 
adjuvant chips, flakes or granules or powders (i.e., containing greater 
than or equal to 5% hydrophobic emollient oils and/or humectants in the 
adjuvant chips, the polyol ester to oil/humectant ratio greater or equal 
to 1:1, and the polyol ester to other structurant ratio greater than 1:1) 
will result in bars, processed by adjuvant technology, with enhanced 
oil/humectant carrying and releasing capabilities. These capabilities are 
crucial to benefit delivery to the skin via personal wash. 
Not to be bound by the theory, it is believed that the adjuvant chips of 
the subject invention entrapped emollient oils by a mechanism that is 
different from those of prior art. That is, hydrophobic oils such as 
sunflower seed oil tend to be miscible with said polyol esters during 
mixing (temperature between 65-120.degree. C.) to form an one phase 
isotropic liquid. Upon cooling, the oil may not be in the form of discrete 
droplets as is found in the adjuvant chips where polyalkylene glycol is 
the major carrier. Instead, oils may exist in the crystalline cracks or 
even in the form of solid solution in the chips of the subject invention. 
The chemical affinity of oil and polyol ester is believed to contribute 
significantly to the stability of the oils in the polyol ester carrier. 
BRIEF SUMMARY OF THE INVENTION 
In one embodiment of the invention, applicants have unexpectedly found 
that, when specific additive compositions are made containing a specific 
polyol ester with defined HLB as the major carrier for liquid hydrophobic 
emollient oil and/or liquid hydrophilic humectant, oil carrying and 
releasing capabilities can be simultaneously improved. 
Specifically, in this embodiment the invention comprises an adjuvant 
composition in the forms of chips, powders, granules or mixtures thereof 
comprising (% by wt.): 
(a) a carrier comprising 
(1) 50% to 95%, preferably 65% to 90% of total chip composition a solid, 
amphiphilic polyol ester having the following structure described as 
##STR1## 
wherein POL represents the polyol moiety, R represents an organic 
hydrophobic group, and one or more R--(C.dbd.O)--O-- functional groups are 
chemically attached to one or more hydroxy groups of the polyol moiety; 
said solid, amphiphilic polyol ester having a hydrophilic-lipophilic 
balance (HLB) number at between 2.5 and 15, preferably between 3 and 8; 
said polyol ester having melting temperature at between 40.degree. C. and 
90.degree. C., preferably at between 45.degree. C. and 70.degree. C.; 
said solid, amphiphilic polyol ester includes but not being limited to 
glycerin fatty esters, such as glyceryl monolaurate and glyceryl 
monostearate; alkylene glycol fatty esters, such as ethylene glycol 
monostearate and ethylene glycol monolaurate; pentaeryrthrityl fatty 
esters such as pentaeryrthrityl stearate; polyglycerin fatty esters such 
as hexaglyceryl tristearate; and 
(2) 0 to 50%, preferably 0 to 30% of total chip composition of an optional 
carrier selected from the group consisting of polyalkylene glycol having 
molecular weight of about 4000-25000, paraffin, C8-C22 carboxylic acid, 
C8-C22 alcohol, water soluble starches and mixtures thereof; 
wherein the total weight percentage of the said optional carrier (2) being 
less than the total weight percentage of the said polyol ester described 
in (1). This specification on the upper limit of the optional structurants 
is a criticality because above this range, the bar has its oil structuring 
capability reduced, which causes oil leakage and/or oil phase separation 
from the bulk (see Example 1); or the bar has its oil releasing capability 
reduced, which prevents the oil release into the aqueous washing liquor 
and deliver to the skin via the personal washing route (see Example 1); 
and 
(b) 5% to 50%, preferably 10% to 35%, most preferably 10% to 25% chip 
composition of a liquid hydrophobic emollient oil, liquid hydrophilic 
humectant or a mixture thereof; 
the weight ratio of said polyol ester as carrier (1) in (a) to the sum of 
said emollient oil and/or humectants (b) being greater than or equal to 
1:1, preferably greater than or equal to 1.5:1; this carrier to emollient 
ratio is a criticality because below this ratio, oil and humectant tend to 
separate from the bulk of the solid matrix. 
In another embodiment, the invention comprises an extruded bar composition 
which is produced using about 5 to 80%, preferably 10 to 50%, most 
preferably 20% to 40% said adjuvant compositions in the form of solid 
chips, flakes, powders, granules or mixtures thereof; and about 20 to 95% 
of a surfactant system (base) in the form of chips, flakes, granules or 
mixtures thereof, wherein the surfactant is selected from the group 
consisting of anionic surfactants, amphoteric surfactants, nonionic 
surfactants, cationic surfactants and mixtures thereof. The surfactant 
system may also contain minor amounts of fragrances, preservative, skin 
feel modifier (e.g., guar) etc. It may also contain free fatty acid and/or 
structurant/inert filler. 
The surfactant system of the second chip preferably comprises either or 
both of the following ingredients: 
(i) carboxylic acid soap; 
(ii) synthetic anionic surfactant, preferably in the solid form at 
25.degree. C., such as sodium cocoyl isethionate, and an amphoteric 
surfactant such as cocoamidopropyl betaine. 
In the third embodiment of the invention, the invention comprises a method 
of making benefit agent containing adjuvant compositions in the form of 
chips, flakes, granules, powders or mixtures thereof comprising: 
(1) 50-95% of a carrier selected from group (a) (1)-(2) above; 
(2) 5 to 50% benefit agents selected from group (b); 
(3) 0-10% optional ingredients selected from thickeners and rheology 
modifiers; 
(4) 0-10% water.

EXAMPLE 1 
Advantages of Using Polyol Ester as Oil Structurant in Comparison with PEG 
8000 and Palmitic/stearic Acid 
Carrying 20% sunflower seed oil, a bar structuring system comprised of 
Polyol ester (glyceryl monolaurate), PEG 8000 and fatty acid was selected 
to test the formulation space for satisfactory oil structuring and 
releasing capabilities. 
Comparative 1 
Shown in the ternary phase diagram (FIG. 1), samples containing high levels 
of PEG 8000 (i.e., concentration of PEG 8000 is above 50% total 
structuring system) separated into an oily top layer and a bottom layer 
comprised of the rest. Cooling the PEG-rich samples to room temperature 
resulted in tacky solids with oil leaking out. This implies that PEG 8000 
is not suitable as the major structurant for a high oil bar, which is 
consistent with the findings discussed in Example 2. 
Comparative 2 
In the fatty acid rich region of the FIG. 1 (i.e., concentration of FA is 
above 60% total structuring system), samples formed single isotropic 
liquids at 95.degree. C. Cooling those samples to 25.degree. C. resulted 
in firm, crisp solids. However, there was no oil released from the solids 
into water, as observed under optical microscopy, and this was not desired 
for benefit delivery. Thus the traditional hydrophobic binders, such as 
stearic/palmitic acid or wax are not ideal as the major structurants for 
the high oil bars. 
Invention 
In the polyol ester rich region (i.e., glyceryl monolaurate concentration 
is above 50%), samples formed single-phase isotropic liquids at 95.degree. 
C. Cooling the molten mixtures to 25.degree. C. resulted in firm, crisp 
solids, which permitted oil release into aqueous phase. Thus monoglyceride 
should be used as the major structurant (i.e., 50% and above of the total 
bar structuring system) for the optimum oil-carrying and releasing. 
EXAMPLE 2 
Preparation of Oil-Containing Adjuvant Chips 
Adjuvant Chips were prepared by first melting 1500 grams of glycerol 
monostearate (from Stepan, under tradename of GMS pure) at temperatures 
between 85.degree. C. and 120.degree. C. using an overhead mixer for 
30-120 minutes and allowing the GMS to deaerate. Then sunflower seed oil 
were stirred in. Upon melting and homogenous mixing, glycerol monostearate 
and sunflower seed oil became miscible with each other and formed an 
isotropic solution. Then the isotropic solution was gradually poured onto 
a chill roll with temperatures set between 0 to 15.degree. C. and 
collected as adjuvant chips or flakes. The adjuvant chips contain 30% 
sunflower seed oil and 70% glycerol monostearate and have melting 
temperatures between 50 and 70.degree. C. 
EXAMPLE 3 
Preparation of a Finished Bar Containing Dove.RTM. 
857 grams of the adjuvant chips (containing 30% sunflower seed oil) 
prepared by Example 1 were combined with 2000 grams of Dove.RTM. as base 
chips containing a surfactant system (representing 70% of final bar) in a 
Ribbon blender were plodded under vacuum in a Weber Seelander duplex 
refiner with screw speed at about 20 rpm. The nose cone of the plodder was 
heated to 45-50.degree. C. The cut billets were stamped into bars using a 
Weber Seelander L4 hydraulic press with a nylon, pillow-shaped die in 
place. 
The Finished bar contains 70% Dove.RTM. as the base chips and 30% said 
adjuvant chips. Said Dove(R) base chips have the following composition: 
about 40-60% fatty acid isethionate; 
about 20-30% fatty acid; 
about 1-10% sodium isethionate; 
about 5% cocoamidopropyl betain; and 
remainder preservative, dyes, water, and other minors. 
Plodding throughput rate was as good as Dove.RTM. alone. The experiments 
show that the emollient containing chips can be successfully incorporated 
into bars without affecting the processing, and thus the emollients (in 
this case, sunflower seed oil can be subsequently delivered. The bar also 
provided interesting sensory cues including creamy, dense lather, and oily 
moisturized skin after-wash. 
EXAMPLE 4 
Preparation of a Finished Bar Containing 82/18 Fatty Acid Soap 
30% adjuvant chips, containing 30% sunflower seed oil, prepared by Example 
1 were combined with 82/18 fatty acid soap as base chips, representing 70% 
of the final bar. The 82/18 fatty acid soap was first heated in a sigma 
blade mixer until the material became soft and pliable. The moisture was 
adjusted so as to have the final product containing 10%-13% moisture. At 
this time perfume was also added so as to have the final product 
containing 1.5% perfume. Then the fatty acid soap chips were refined into 
3 mm diameter pellets and mixed in a bowl with the adjuvant chips. The 
blend was then re-refined into 3 mm diameter pellets to insure homogeneity 
of the 82/18 soap and the adjuvant chips. Further processing produced 
extruded billets which were cut and stamped into bars. No point of the 
process was hindered by the addition of adjuvant chips to the soap base.