Note: Descriptions are shown in the official language in which they were submitted.
CA 02248008 1998-09-02
WO 97/34992 PCT/EP97/00914
BAR COMPOSITION COMPRISING COPOLYMER MILDNESS ACTIVES
The present invention relates to synthetic bar
compositions (i.e., bars in which at least some fatty acid
soap has been replaced by synthetic surfactants, such as
anionic surfactants).
BACKGROUND
Traditionally, soap has been utilized as a skin
cleanser. Notwithstanding its many advantages (e. g.,
inexpensive, easy to manufacture into bars, having good
lathering properties), soap is a very harsh chemical.
Irritated and cracked skin often result from the use of soap,
especially in colder climates.
In order to maintain cleaning effectiveness and reduce
harshness, the art has used synthetic surfactants to replace
some or all of the soap. In particular, anionic surfactants
have been used because these tend to most clearly mimic the
lather generation which soap readily provides.
Anionic surfactants, however, are still harsh. One
method of reducing the harshness of anionic surfactants is to
utilize other surfactants such as nonionic or other mildness
surfactants (e. g., amphoteric). The use of surfactants other
than anionics, however, can introduce other problems. For
example, nonionic surfactants generally do not generate
creamy thick lather as do anionics; and both nonionics and
A
amphoterics, for example can be sticky and introduce
processing difficulties.
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WO 97/34992 PCT/EP97/00914
2
For this reason, the art is always searching for
materials which are milder than anionic and/or which can be
used to replace at least some of the anionic surfactants,
yet, which do not simultaneously seriously compromise lather
i
generation or processing efficiency. Further, even if the
anionic is not substituted, the art is always searching for
materials which can substitute for inerts and/or other
fillers and produce enhanced mildness.
Unexpectedly, applicants have found that the use of
relatively low levels of specific nonionic polymeric
surfactants can be used to obtain these goals. That is, at
levels no higher than 10o by wt. of the bar composition, the
polymers provide enhanced mildness without sacrificing
processability or lather. While not wishing to be bound by
theory, it is believed that the copolymers may be interacting
with anionic surfactantto-form polymer-surfactant complexes
thereby reducing free anionic surfactant (known for its
harshness) from the bar.
The use of polyoxyethylene polyoxypropylene (EO-PO)
nonionic polymeric surfactants in bar compositions per se. is
not new.
U.S. Patent No. 3,312,627 to Hooker, for example,
teaches bars substantially free of anionic detergents
comprising 0 to 70o by weight EO-PO polymer, polyethylene
glycol (PEG) or derivatives of these compounds as base; and
10 to 70$ of a nonionic lathering component. 2n order to
give these bars more "soap-like~~ characteristics, the
reference contemplates use of 100-800 lithium soap. 2t is
clear that use of lithium soap is unique to the invention
(column 8, lines 20-23) and that use of other soaps or ,
anionic (other than fatty acid lithium soap) is not
contemplated. Thus, this reference clearly differs from the
CA 02248008 2005-O1-07
. f . . f . . 1 . .
C6338' f f f f .. f. . . . . . .
.
t f ( a f- t . t . . . ..
, . . . . . ... . .
.
1 . t f . t . . ..
... ~f .. .... .. ..
- 3 -
composition of the invention which comprise 10 to 50~ of a
surfactant system of which at least 50~ (though no more than
40~ total of total composition) is anionic surfactant.
U.S. Patent No. 3,766,097 to Rosmarin discloses the use
of 30~-50$ of a specified EO-PO copolymer (Pluronic F-127)
in a bar using sodium cocoyl isethionate as primary anionic
surfactant. Here again, the polymer is being used as a bar
structurant at levels well above the 10~ upper limit of the
subject invention. There is no teaching or suggestion that
the polymers can be used in combination with anionic at much
lower levels to unexpectedly and remarkably enhance mildness
(e. g., reduce irritation) at these low levels.
U.S. Patents Nos. 6,028,042 and 6,251,843 to Chambers et al. (assigned
to Lever Brothers) teache that certain solid EO-PO polymers
can be used as alternatives to solid polyethylene glycols
(PEGS) as bar structurants for synthetic bar formulations.
Once more, the polymers are contemplated for use as
structurants, i.e., at much higher levels than the levels
under 10~ by wt. of the subject application. There is again
no teaching or suggestion that the polymers can be used at
much lower levels (both as total percentage of compositions
and as ratio to total level of anionics) to provide enhanced
mildness (i.e., reduced skin irritation).
WO-A-9421778 discloses a formulation of a synthetic
detergent bar intended for personal washing which are easily
processed; the structurant being optionally a polyethylene
glycol or a polyethylene oxide-polypropylene oxide block
copolymer.
CA 02248008 1998-09-02
C 6 3 3 8 . . : f. ., .. - ,.
f
- 3a -
Applicants have now found that the use of relatively
small amounts of defined polyoxyethylene-polyoxypropylene
nonionic polymer surfactants in bar compositions comprising
primarily anionic surfactant systems remarkably and
unexpectedly enhances the mildness of these bars.
~,iJIEt~IDLD SttEET
CA 02248008 1998-09-02
WO 97/34992 PCTlEP97/00914
4
More specifically, applicants' invention relates to bar
compositions comprising:
(a) 10~ to 70o by wt. total composition of a surfactant
system selected from the group consisting of
anionic surfactants, nonionic surfactants (other
than the nonionic EO-PO polymer), cationic
surfactants, amphoteric surfactants and mixtures
thereof ;
wherein the anionic surfactant comprises at least 50~,
preferably at least 60~ of said surfactant system and wherein
the anionic component further comprises no more than about
40~ by wt. of total composition;
(b) 20~ to 85~ by wt., preferably 30 to 70$ total
composition of a bar structurant selected from the
group consisting of alkylene oxide compounds having
a molecular weight of from about 2000 to about
25, 000, preferably 3, 000 to 10, 000; CR-CZZ free
fatty acids, paraffin waxes; water soluble starches
(e.g., maltodextrin); and C8-C2o alkanols; and
(c) 3~ to 10~ by wt. total composition of a
polyoxyethylene-polyoxypropylene nonionic polymer
surfactant (EO-PO polymer);
wherein ratio of anionic surfactant to EO-PO polymer is
between 2.5:1 to 10:1, preferably 4:1 to 7:1.
The composition may optionally comprise 0~ to 250,
preferably 2~ to 15o by wt. solvent such as ethylene oxide or
propylene oxide.
Figure 1 shows the Zein o dissolved by acyl ,
isethionate/cocoamidopropyl betaine as a function of Pluronic
(EO-PO polymer) concentration. In contrast to PEG 8000,
~ -.
...,._. . 1. - i ,: i E C r .: ~ '
F: ~ t
CA 02248008 1998-09-02
WO 97/34992 PCT/IiP97/00914
Pluronic F88 and 2588 significantly reduced the Zein
dissolved at even quite low levels, such as 0.3 wt.~ (at
sodium acyl isethionate (SAI) to EO-PO weight ratio at
1:0.15, this is equivalent to about 4~ EO-PO in the bar of
5 Formulation (a) in Table 2, Example 1). Therefore the
irritation potential of a personal washing bar can be further
reduced by including relatively low levels (i.e. 10~ and
under in a full bar composition; this would correspond to
about 0.74 in the liquor as shown in Figure 1) of Pluronics
in the bar formulation. The data also showed that EO-
terminated Pluronic F88 is potentially a better mildness
enhancer than the PO-terminated Pluronic 2588.
Figure 2 shows the EO-PO polymer of the invention
significantly reduces skin irritation caused by DEFI.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to synthetic bar
compositions wherein the majority of the surfactant system of
the bar comprises anionic surfactant; and to specific
nonionic copolymers which can be used in such bar
compositions to significantly enhance bar mildness.
More specifically, the bar compositions comprise
(a) 10~ to 70a by weight total composition of a
surfactant system wherein said surfactant system is
selected from the group consisting of anionic
surfactants, nonionic surfactants (other than the
EO-PO polymer), amphoteric surfactants, cationic
surfactants and mixtures thereof, wherein the
anionic comprises 500 or more, preferably 600 or
more, of the surfactant system and the anionic
further comprises no more than 40~ of the total
CA 02248008 1998-09-02
WO 97/34992 PCT/EP97/00914
6
composition;
(b) 20~ to 85$ by wt. total composition of a bar
structurant selected from the group consisting of
polyalkylene glycols having a MW of from about
2,000 to 25,000 (which may optionally include 1~ to
5$ higher molecular weight polyalkylene glycols
having MW from 50,000 to 500,000, especially around
100, 000) ; C8 to Ca4, preferably Clz to C24 fatty
acids; paraffin waxes; water soluble starches
(e. g., maltodextrin); and C$ to CZO alkanols (e. g.,
cetyl alcohol); and
(c) 3~ to 10~ by weight total composition of a
-- polyoxyeth lene,
y polyoxypropylene nonionic polymer
surfactant
wherein ratio of anionic surfactant to EO-PO polymers is
between 2.5:1 to 10:1, preferably 4:1 to 7:1.
Surfactant v m
The anionic detergent active which may be used may be
aliphatic sulfonates, such as a primary alkane (e. g., C8-Caa)
sulfonate, primary alkane (e.g. , C8-C2~) disulfonate, C8-C2z
alkene sulfonate, C8-Caa hydroxyalkane sulfonate or alkyl
glycerol ether sulfonate (AGS); or aromatic sulfonates such
as alkyl benzene sulfonate.
The anionic may also be an alkyl sulfate (e.g., C~~-C1$
alkyl sulfate) or alkyl ether sulfate (including alkyl
glycerol ether sulfates). among the alkyl ether sulfates are
those having the formula:
RO ( CHZCHZO ) nS03M
CA 02248008 1998-09-02
WO 97/34992 PCT/EP97/00914
7
wherein R is an alkyl or alkenyl having 8 to 18 carbons,
preferably 12 to 18 carbons, n has an average value of
greater than 1.0, preferably greater than 3; and M is a
solubilizing cation such as sodium, potassium ammonium or
substituted ammonium. Ammonium and sodium lauryl ether
sulfates are preferred.
The anionic may also be alkyl sulfosuccinates (including
mono- and dialkyl, e.g., C6-C2~ sulfosuccinates); alkyl and
acyl taurates, alkyl and aryl sarcosinates, sulfoacetates,
C8-C22 alkyl phosphates and phosphates, alkyl phosphate esters
and alkoxyl alkyl phosphate esters, acyl lactates, C8-CZZ
monoalkyl succinates and maleates, sulphoacetates, alkyl
glucosides and aryl isethionates.
Sulfosuccinates may be monoalkyl sulfosuccinates having
the formula:
R'OzCCH~CH ( S03M) C02M; and
amide-MEA sulfosuccinates of the formula:
R°CONHCH2CHZO2CCH2CH ( S03M) COZM
wherein R4 ranges from CB-C22 alkyl and M is a
solubilizing cation.
Sarcosinates are generally indicated by the formula:
3 0 R' CON ( CH3 ) CHZCO~M,
wherein R ranges from C~-C~fl alkyl and M is a
solubilizing cation.
CA 02248008 2005-O1-07
WO 97/34992 PGT/EP97/00914
8
Taurates are generally identified by formula:
RZCONR'CH2CHZSO~M
wherein R~ ranges from Cg-C,8 alkyl, R' ranges from C,-C4
a alkyl and M is a solubilizing cation.
Particularly preferred are the Ce-C18 aryl isethionates.
These esters are prepared by reaction between alkali metal
isethionate with mixed aliphatic fatty acids having from 6 to
18 carbon atoms and an iodine value of less than 20. At -1
least 75$ of the mixed fatty acids have from 12 to 18 carbon
atoms and up to 25~ have from 6 to 10 carbon atoms.
Acyl isethionates, when present, will generally range
from about 10$ to about 70$ by weight of the total
composition. Preferably, this component is present from
about 30~ to about 60~.
The aryl isethionate may be an alkoxylated isethionate
such as is described in Ilardi et al., U.S. Patent No.
5,393,466. This compound has the general formula: ence .
O X Y
R C-O-CH-CHI-(O~H-CH~~-S0~3M+
wherein R is an alkyl group having 8 to 18 carbons, m is
an integer from 1 to 4, X.and Y are hydrogen or an alkyl
group having 1 to 4 carbons and M' is a monovalent cation
such as, for example, sodium, potassium or ammonium.
The anionic surfactant comprises 50% or more of the
total surfactant system, but should comprise no more than 90$
by wt. of the total composition.
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WO 97/34992 PCT/EP97/00914
9
Amphoteric detergents which may be used in this
invention include at least one acid group. This may be a
carboxylic or a sulphonic acid group. They include
quaternary nitrogen and therefore are quaternary amido acids.
They should generally include an alkyl or alkenyl group of 7
to 18 carbon atoms. They will usually comply with an overall
structural formula.
O R
R~ C-NH (CH2) n N3 X-Y
where R1 is alkyl or alkenyl of 7 to 18 carbon atoms;
RZ and R3 are each independently alkyl, hydroxyalkyl or
carboxyalkyl of 1 to 3 carbon atoms;
m is 2 to 4;
n is 0 to 1;
X is alkylene of 1 to 3 carbon atoms optionally
substituted with hydroxyl, and
~5
Y is -COz - or -S03-
Suitable amphoteric detergents within the above general
formula include simple betaines of formula:
0
2
R
CH~C02
i3
R
5
CA 02248008 1998-09-02
C6338 --"~: ..~ r ~ - '
- 10 -
and amido betaines of formula:
z
R
R1 CONH ( CH2 ) ~N+-CH,, S03
13
R
wherein m is 2 or 3.
In both formulae R1, R~, and R3 are as defined
previously. R1 may in particular be a mixture of C12 and C14
alkyl groups derived from coconut so that at least half,
preferably at least three quarters of the groups R are
preferably methyl.
A further possibility is that the amphoteric detergent
is a sulphobetaine of formula
2 0 R'
Rl- ~+3- (CH2 ) 3503_
3
R
or
a
R
i + -
3 0 R CONH ( CHZ ) m-N -CH'S03
13
R
wherein m
is 2 or 3, or variants of these in which -(CH2)3 S03 is
replaced by
AMFraosQ s~~Fr
CA 02248008 2005-O1-07
WO 9?!34992 PGTIEP9?!00914
11
OH
-CHZ ~I-ICH., S03
in these formulae R', RZ and R' are as discussed
previously.
The nonionic which may be used includes in particular
the reaction products of compounds having a hydrophobic group
and a reactive hydrogen atom, for example aliphatic alcohols,
acids, amides or alkyl phenols with alkylene oxides,
especially ethylene oxide either alone or with propylene
oxide. Specific nonionic detergent compounds are alkyl (Cs-
CZZ) phenols-ethylene oxide condensates, the condensation
products of aliphatic (CeC,B) primary or secondary linear or
branched alcohols with ethylene oxide, and products made by
condensation of ethylene oxide with the reaction products of
propylene oxide and ethylenediamene Other so-called nonionic
detergent compounds include long chain tertiary amine oxides,
long chain tertiary phosphine oxides and dialkyl sulphoxides.
The nonionic may also be a sugar amide, such as a
-? polysaccharide amide. Specifically, the surfactant may be
one of the lactobionamides described in U.S. Patent No.
5,389,279 to Au et al. or it may be one of the sugar amides described in
patent
No. 5,009,814 to Kelkenberg.
Other surfactants which may be used are described in
U.S. Patent No. 3.723.325 to Parran Jr.
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WO 97/34992 PGT/EP97/00914
12
Nonionic and cationic surfactants which may be used include any one of
those described in U.S. Patent No. 3,761,418 to Parran, Jr. Those included are
the aldobionamides taught in U.S. Patent No. 5,389,279 to Au et al. and the
polyhydroxy fatty acid amides as taught in U.S. Patent No. 5,312,934 to
Letton.
The surfactants generally comprise 10 to 50$ of the
total composition except, as noted that anionic comprises 50~
or more of the surfactant system and no more than 40% total.
A preferred surfactant system is one comprising acyl
isethionate and a amphoteric, i.e., betaine, as co-
surfactant.
The structurant of the invention can be a water soluble
or~water insoluble structurant.
Water soluble structurants include moderately high
molecular weight polyalkylene oxides of appropriate melting
point (e.g. , 40° to 100°C, preferably 50° to 90°)
and in
particular polyethylene glycols or mixtures thereof.
Polyethylene glycols (PEG~s) which are used may have a
molecular weight in the range 2,000 to 25,000, preferably
3,000 to 10,000. However, in some embodiments of this
invention it is preferred to include a fairly small quantity
of polyethylene glycol with a molecular weight in the range
from 50,000 to 500,000, especially molecular weights of
around 100,000. Such polyethylene glycols have been found to
improve the wear rate of the bars. It is believed that this
CA 02248008 1998-09-02
WO 97/34992 PCT/EP97100914
13
is because their long polymer chains remain entangled even
when the bar composition is wetted during use.
If such high molecular weight polyethylene glycols (or
~5 any other water soluble high molecular weight polyalkylene
oxides) are used, the quantity is preferably from 1~ to 5~,
more preferably from 10 or 1.5~ to 4~ or 4.5~ by weight of
the composition. These materials will generally be used
jointly with a large quantity of other water soluble
structurant such as the above mentioned polyethylene glycol
of molecular weight 2,000 to 25,000, preferably 3,000 to
10,000.
In7ater insoluble structurants also have a melting point
in the range 40-100°C, more preferably at least 50°C, notably
50°C to 90°C. Suitable materials which are particularly
envisaged are fatty acids, particularly those having a carbon
chain of 12 to 24 carbon atoms. Examples are lauric,
myristic, palmitic, stearic, arachidic and behenic acids and
mixtures thereof. Sources of these fatty acids are coconut,
topped coconut, palm, palm kernel, babassu and tallow fatty
acids and partially or fully hardened fatty acids or
distilled fatty acids. Other suitable water insoluble
structurants include alkanols of 8 to 20 carbon atoms,
particularly cetyl alcohol. These materials generally have a
water solubility of less than 5 g/litre at 20°C.
Soaps (e. g., sodium stearate) can also be used at levels
of about 1g to 15%. The soaps may be added neat or made in
situ by adding a base, e.g., NaOH, to convert free fatty
acids.
The relative proportions of the water soluble
structurants and water insoluble structurants govern the rate
at which the bar wears during use. The presence of the
"~..~t,.vs~~ ,~' t r;~~ E~. ..'
CA 02248008 1998-09-02
C6338 '_
- 14 -
water-insoluble structurant tends to delay dissolution of
the bar when exposed to water during use and hence retard
the rate of wear.
The structurant is used in the bar in an amount of 20~
to 85~, preferably 30o to 70~ by wt.
The polyoxyethylene polyoxypropylene nonionic
copolymers (EO-PO copolymers) of the subject invention are
generally commercially available polymers having a broad
molecular weight range and EO/PO ratio and a melting
temperature of from about 25° to 85°C, preferably 40° to
65°C.
Generally, the polymers will be selected from one of
two classes of polymers, i.e., (1) (EO)m(PO)n(EO)m type
copolymers or (PO)n(EO)m(PO)n type copolymers of defined m/n
ratio and optional hydrophobic moieties (e. g.,
decyltetradecanol ether) attached to either EO or PO
compounds (such products are commercially available for
example, from BASF under the Trademark Pluronic~R~ or
Pluronic-R~R~, respectively); or (2) EO-PO polymers with
amine constituents such as NZCzH4 ( PO) 4n (EO) 4m or
N2C2H4(EO)4m(PO)4n with defined values of m and n and optional
hydrophobic moieties attached to either EO or PO components
(such products are commercially available, for example from
BASF as Tetronic~R~ and Tetronic-R~R~, respectively).
Specifically, examples of various Pluronic and Tetronic
EO-PO polymers are set forth in Table 1 below wherein Tm (°C)
and Ross Miles foam height data (measured at 0.1~ and 50°C)
were digested from literature from BASF.
~EN~~~ g~t~E~
CA 02248008 1998-09-02
WO 97/34992 PCT/EP97/00914
Polymer Tm ( C Foam EO and PO
) Heights Number
(ml)
Pluronic: (EO)m-(PO)n-(EO)m m/n
5 F38 48 35 46/16
F68 52 35 75/30
F77 48 47 52/35
F87 49 44 62/39
F88 54 48 97/39
10 F98 58 43 122/47
F108 57 41 128/54
F127 56 41 98/67
Pluroni. C-R ( POn- ( EO ) m-
: ( PO ) "
1088 46 20 90/9
15 1788 53 2 155/15
2588 54 15 227/21
Tetronic : NaC2H4- ( PO ) 4~
( EO ) ,,"
707 46 60 35/12
1107 51 50 64/20
908 58 40 85/16
1307 54 40 78/25
1508 60 40 159/30
Tetronic-R: N.,C~HQ- (EO) Qm
( PO) 9"
9088 47 U '~.3-U%1~/
11087 47 0 64/21
15088 53 0 12/29
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W~ 97/34992 PCT/EP97/00914
16
In general, the molecular weight of the copolymers used
ranges from 2,000 to 25,000 (preferably 3,000 to 20,000). The ,
EO-terminated polymers (Pluronic and Tetronic) are preferred to
the PO-terminated ones (Pluronic-R and Tetronic-R) for the ,
advantages of mildness enhancement and lather generation. To
ensure water solubility, we prefer that the portion of ethylene
oxide moiety per mole is between 50~ to 90~ wt., more
preferably 60-85~ wt. 2nother words, 2m:n (for Pluronic) or
m:n (for Tetronic) ranges from 1.32 to 11.9, preferably 2.0 to
7.5.
As noted, melting temperature of the compounds must be
about 25°-85°, preferably 40° to 65°C, the latter
being more
favorable for processing (e. g., chips form more easily and logs
plod more readily).
Bars of the invention may comprise 0~ to 25~, preferably
2~ to 15~ by wt. of an emollient such as ethylene glycol,
propylene glycol and/or glycerine.
Bar compositions of this invention will usually contain
water, but the amount of water is only a fairly small
proportion of the bar. Larger quantities of water reduce the
hardness of the bars. Preferred is that the quantity of water
is not over 15~ by weight of the bars, preferably l~ to about
10~, more preferably 3~ to 9$, most preferably 3$ to 8~.
Bars of this invention may optionally include so-called
benefit agents - materials included in relatively small
proportions which confer some benefit additional to the basic
cleansing action of the bars. Examples of such agents are: o
skin conditioning agents, including emollients such as fatty
alcohols and vegetable oils, essential oils, waxes,
. CA 02248008 1998-09-02
. . :,
C6338 _ " -... .n C
- 17 -
phospholipids, lanolin, anti-bacterial agents and sanitizers,
opacifiers, pearlescers, electrolytes, perfumes, sunscreens,
fluorescers and coloring agents. Preferred skin conditioning
agents comprise silicone oils, mineral oils and/or glycerol.
The composition may also comprise a polyol.
The examples below are intended to better illustrate the
invention, but are not intended to be limiting in any way.
All percentages, unless otherwise noted, are intended to
be percentages by weight.
EXAMPLES
I~iethodoloav
Zein dissolution test was used to preliminarily screen the
irritation potential of the formulations studied. In an 8
oz. jar, 30 mLs of an aqueous dispersion of a formulation
were prepared. The dispersions sat in a 45°C bath until fully
dissolved. Upon equilibration at room temperature, 1.5 gms
of zero powder were added to each solution with rapid
stirring for one hour. The solutions were then transferred
to centrifuge tubes and centrifuged for 30 minutes at
approximately 3,000 rpms. The undissolved zein was isolated,
rinsed and allowed to dzy in a 60°C vacuum oven to a constant
weight. The percent zero solubilized, which is proportional
to irritation potential, was determined gravimetrically.
Patch test was used to evaluate skin mildness of aqueous
dispersions containing 1~ DEFI active (sodium cocoyl
AMENDED SN~ET
CA 02248008 1998-09-02
WO 97/34992 PCT/EP97/00914
18
isethionate) and different levels of the structurant/coactives.
Patches (Hilltop~R? Chambers, 25 mm in size) were applied to the
outer upper arms of the panelists under bandage type dressings
(Scanpor~R~ tape). After each designated contact periods (24
hrs. for the first patch application, 18 hrs. for the second
and third applications), the patches were removed and the sites
were visually ranked in order of severity (erythema and
dryness) by trained examiners under consistent lighting.
Formulation Processincx
Bar formulations were prepared in a 2-liter Patterson
mixer with a sigma type blade. The components were mixed
15 together at ~95°C, and the water level was adjusted to
approximately 8-10 wt. g. The batch was covered to prevent
moisture loss, and mixed for about 15 minutes. Then the cover
was removed and the mixture was allowed to dry. The~moisture
content of the samples taken at different times during the
20 drying stage was determined by Karl Fisher titration with a
turbo titrator. At the final moisture level (~5g), the
formulation was dropped onto a heated applicator roll and then
was chipped over a chill roll. The chill roll chips were
plodded under vacuum in a Weber Seelander duplex refiner with
screw speed at ~20 rpm. The nose cone of the plodder was
heated to 45-50°C. The cut billets were stamped into bars
using a Weber Seelander L4 hydraulic press with a nylon,
pillow-shaped die in place.
Bars were also prepared by a cast-melt process. First,
the components were mixed together at 80-120°C in a 500 ml
beaker, and the water level was adjusted to.approximately 10-15
wt.~. The batch was covered to prevent moisture loss and was
mixed for about 15 minutes. Then the cover was removed, and
the mixture was allowed to dry. The moisture content of the
CA 02248008 1998-09-02
WO 97/34992 PCT/EP97/00914
19
samples taken at different times during the drying stage and
was determined by Karl Fisher titration with a turbo titrator.
At the final moisture level (~5$), the mixture in the beaker
tin the form of a free-flow liquid) was dropped into bar-molds
and was allowed to be cooled at room temperature for four
hours. Upon solidification, the mixture was casted in the bar
mold into a bar.
Example 1
Components as listed in Table 2 below were melted together
at 80°C-120°C to produce a material consisting predominantly of
a liquid phase. All amounts are provided in percentage by
weight. On cooling to 10°C-50°C by a chill-roll, the
formulations formed plastic-like solids that were plodded using
the extrusion equipment described above (i.e., formulation
processing section) and pressed into bars using the single bar
press. Identical formulations were also formed into bars by
using the casting process from the hot melt. These bars
contain a major DEFI active and an optional cocoamidopropyl
betaine coactive. These bars provided rich, creamy and
slippery lather; the skin-feel of the bars were found to be'
smooth and non-tacky.
a
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WO 97/34992 PCT/EP97/00914
TABLE 2
Formulation A ~ B C D
5 Sodium acyl 27.8 27.0 27.Og 27.8
isethionate (from
DEFI*)
Cocoamidopropyl 5.2 5.0 5.0 5.2
betaine
10 PEG 8000** 32.1 29.5 35.0 45.1
PEG 4000*** 3.1 0.0 0.0 0
Stearic-palmitic 11.6 8.6 9.0 11.6
acid
Maltodextrin 10.3 10.0 0.0 4.4
15 Pluronic F88 4.0 5 10 ~
Tetronic 1107 0 5 0 _
;.?
Perfume 0 0.3 0.3 0
Sodium Stearate 0 0 5.0 0
Titanium Dioxide 0 0 0.5 0
20 EHDP 0 0.1 0.1 p
EDTA 0 0.1 0.1 0
Misc. Salts 0 2.9 2.9 0
Water 5.9 6.5 5.1 5.9
*DEFI: directly esterified fatty acid isethionate, which
a.s a mixture containing about 74~ by weight of fatty aryl
isethionate, 23~ stearic-palmitic acid and small amounts of
other materials, manufactured by Lever Brothers Co., U.S.
** PEG 8000: polyoxyethylene glycol with mean molecular
weigh at 8000; PEG 4000: polyoxyethylene glycol with mean
molecular weight at 4000.
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21
Components as listed in Table 3 below were preferably
processed using a cast-melt approach described in the
methodology section. All amounts are given in percentage of
weight. These~bars used sodium lauryl sarcosinate (formulation
E, G) and sodium lauryl sulphate (formulation F) as the major
anionic detergent with optional cocoamidopropyl betaine as a
coactive. These bars provided rich, creamy and slippery lather
and smooth skin feel.
Formulation (E) (F) (G)
Sodium Lauryl 15 0.0 27.0
Sarcosinate
Cocoamidopropyl 5.0 5.0 5.0
Betaine
SLES (3E0) 5.0 20.0 0.0
Stearic-palmitic Acid 5.0 5.0 5.0
PEG 8000 '25.0 44.0 39.0
PEG 6000 27.0 8.0 5.0
Pluronic F88 10.0 10.0 10.0
Paraffin Wax 2.0 2.0 3.0
Perfumes 1.0 1.0 1.0
Water 5.0 5_0 5.0
The irritation reduction potential of Pluronics was
investigated using Zein dissolution experiments. As indicated
' in Tables 4 and 5, Pluronic surfactants, as a class, are
significantly more effective than PEG in reducing the Zein o
dissolved by a 1o aqueous DEF2 suspension (DEF2 is a sodium
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22
aryl isethionate/fatty acid mixture defined in the Table 2 of
Example 1). The data in Tables 4 and 5 also showed that EO
terminated Pluronic F127 is potentially a better mildness
enhancer than the PO-terminated Pluronic 2588. Table 6 showed
that EO-PO can significantly reduce the Zein ~ dissolved by
even a quite mild detergency system (DEFI/cocoamidopropyl
betaine): Tables 4, 5 and 6 are set forth below.
TABLE 4 -
Component g Zein Dissolved
1$ DEFI 23.9
1$ DEFI + 0.8$ PLU.F127* 17.8
wa t er _ 9 . 0
Component ~ Zein Dissolved
PEG 8K 20.8
5~ PLU.25R8** 8.9
5~ PLU.F127* 4.1
TABLE 6***
n~
Component ~ Zein Dissolved
~~i~~
5~ PEG 17.4
5~ PLU.F127 3.6
* Structure of PLU F127 is EOqR POE., E09
** Structure ofPLU 2588 is PO~1 EO~r, PO~1
*** Components tested in mild system comprising 1$ DEFI/0.8$
cocoamidopropyl betaine
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23
Three day skin patch tests showed that Pluronic F88
significantly reduced the skin irritation caused by DEFI, even
at low levels of addition. As shown in Figure 2, at a Sodium
aryl isethionate (SAI) Pluronic F88 weight ratio around 1:0.37
(equivalent to 10o EO-PO in the bar of Formulation (B) or (C)
in Table 2 of Example 1), Pluronic F88 reduced the skin
irritation of a DEFI/betaine liquor significantly. In
contrast, even at SAI/PEG 8000 weight ratio as low as 1:1.67
(effectively 45o PEG 8000 in the bar of formulation D, Table 2)
PEG 8000 made no measurable mildness contribution to the
SAI/CAP betaine aqueous liquor.
dame 1 a
Zein dissolution experiments (Table 7 below) revealed
that Pluronic F88 can significantly reduce the amount of Zein
dissolved by many different types of anionic surfactants
commonly used in personal washing products. Thus inclusion of
EO-POs in the bar formulations containing the anionic
surfactants listed in Table 7 can effectively enhance the
mildness of the bars.
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24
'T'A3T,E 7
Formulation (in Zein ~ Dissolved
distilled water) Pluronic F88 (w/w)
Anionic Surfactant (Standard dev.
2$)
1~ Sodium Lauryl 0.73 37.1%
Sarcosinate
1~ Sodium Lauryl 0 43
8
Sarcosinate .
1~ SLES (3E0) 0.73$ 28.6
1~ SLES (3E0) 0 35.$
1~ Sodium Lauryl Sulfate 0.73 59.0
1~ Sodium Lauryl Sulfate 0 66.9
1~ Sodium Soap (82:18 0.73 49.7
Tallowate/Cocoate)
l~ Sodium Soap 0 59.7
2~ Sodium Lauryl 0.73 38.5
Isethionate
l~ Sodium Lauryl 0 46.5
Isethionate
