Note: Descriptions are shown in the official language in which they were submitted.
WO 94121778 PCT/EP94/00792
215 '~'~ 7 3
1
SYNTHETIC DETERGENT BAR ANt~ MANUFACTURE THEREOF
This invention relates to synthetic detergent bars and
detergent compositions which can be shaped into bars.
Washing bars can be classified into soap bars, mixed
active bars containing a significant proportion of soap
and thirdly synthetic detergent bars containing only a
small proportion of soap or none at ail.
Conventional soap bars comprise a large proportion,
typically 60-80% by weight, of fatty acid soap. Fatty
acid soaps are selected to provide a balance of soluble
and insoluble soaps which provide the required functional
properties as regards lather formation and bar structure.
Conventional soap bars are manufactured by milling,
plodding and stamping a semi-solid mass of soap and other
components.
Bars are known which contain a mixture of soap and
synthetic detergent where the amount of soap may be less
than the amount of synthetic detergent but is
nevertheless still a significant contributor to the
content of the bar. In such bars, as in conventional
soap bars, the content of soap especially the insoluble
soap contributes to the structure and physical properties
of the bar.
CONFIRMATION COPY
- 3520
- 2 -
The third category is synthetic detergent bars, often known
as "Syndet" bars, in which there is no soap or only a small
amount and the detergent active is mostly or wholly a
synthetic, non-soap, detergent. Generally such bars contain
a substantial proportion of material which is not a detergent
and which serves to give structure to the bar. Such
"structurants" are normally water-insoluble and include such
materials as starch and kaolin. The bars frequently also
contain a plasticiser: known plasticisers include stearic
acid and cetyl alcohol. PCT 92/13060 discloses a syndet bar
comprising a long chain alkyl sulphate, water and a three
component plasticiser system, containing free fatty acid;
monogylceride and polyethylene glycol. Bars containing
polyethylene glycol are also known from US 3687 855 and 2987
484. US 3687 855 discloses iodine-containing germicidal bars
in which the polyethylene glycol facilitates homogeneous
distribution of the active germicidal compound and detergent
agent through the bar. Polyethylene glycol is mentioned as a
filler in US 2987 484 for bars made by a closed-die moulding
process which involves the use of a molten mixture of active
components.
Known surfactants for Syndet bars include primary alkyl
sulphates, alkyl ether sulphates, betaines, sarcosinates,
sulphosuccinates and isethionates. These syndet bars
containing no soap or only a small proportion of soap are
traditionally produced by energetic working of a physical mix
of structurant, plasticiser and surfactant, i.e. both the
soluble and insoluble components, in a high shear mixer to an
end point at which the product is not gritty. The mix is
then formed into 'syndet' bars.
The known process has several disadvantages in that the
physical mixing step is performed batchwise and requires an
energetic mixer.
AMENDED St-IEET
IPEA/EP
520 215 77'3
- 2a -
We have now found that by adopting a novel composition,
syndet bars may be produced by a process which dispenses with
S the known energetic working step.
c -~ :=~ ~
A~iE
~ PEA/EP
WO 94/21778 PCT/EP94100792
21 5 77 7 3
3
In contrast with prior compositions and processes the
invention relies on ingredients which are molten at
conveniently accessible temperatures but which are above
the temperatures normally encountered during use of
"Syndet" bars. As a result the necessary intimate mixing
of the ingredients of the bar can be accomplished by
simple mixing while the bar composition is liquid rather
than by relying on energetic working to achieve intimate
mixing of a mixture of solids.
Accordingly, the present invention provides a detergent
composition which is, or can be shaped into, a synthetic
detergent bar, the composition comprising:
(a) 10-60$wt of a synthetic, non-soap detergent,
(b) 20-SO~wt of water soluble material which is one or
more polyethylene glycols having a molecular
weight in the range of 1500-10,000 and a melting
point in the range 40°C to 100°C,
(c) 5-50~wt of water-insoluble C12-C24 fatty acid,
Cg-C20 alkanols, or mixtures thereof having a
melting point in the.range 40°C to 100°C, and
(d> 3-20~wt of water.
It is desirable that the content (if any) of material
other than said synthetic non-soap detergent (a) which
does not melt below 100°C is less than 20°s by weight of
the composition.
A
V4'O 94/21778 PCT/EP94I00792
21 5 77 7 3
4
In many embodiments of this invention the content of the
synthetic detergent (a) will lie in the range 10 to 500
by weight. Preferably the composition will contain some
water, in an amount from 3°s or 5% to 20% better at most
5. 15o by weight of the composition.
Constituent (b) of the composition
is a water-soluble material which melts at a temperature
l0 in the range 40-100°C and serves as a bar structurant.
Such a material assists in giving the desired properties
notably that the bar has a rigid solid form.
It will also be noted from the above that the composition
15 of the bar can tolerate the presence of some material
which does not melt at temperatures below 100°C. Such
material can also serve as a structurant. Such material
is not an essential requirement and it may be entirely
absent. If such material is present; the molten
20 composition will not be fully liquid at temperatures of
up to 100°C unless the non-melting material dissolves in
the other materials present. We have found that a
moderate amount of material which does not melt can be
dispersed in the molten composition while it remains
25 sufficiently liquid to be stirred without requiring
energetic working. As will be mentioned again below,
this material which disperses but does not melt may be at
least part of the non-soap synthetic detergent (a) and/or
A
WO 94/21778 3 PCT/EP94/00792
material other than this category.
Suitable synthetic detergents (a) are: alkyl ether sulphates;
alkylethoxylates; alkyl glyceryl ether sulphonates; alpha
5 olefin sulphonates; acyl taurides; methyl acyl taurates; N-
acyl glutamates; acyl isethionates; anionic acyl sarcosinates;
alkyl phosphates; methyl glucose esters; protein condensates;
ethoxylated alkyl sulphates; alkyl polyglucosides; alkyl amine
oxides; betaines; sultaines; alkyl sulphosuccinates, dialkyl
sulphosuccinates, acyl lactylates and mixtures thereof. The
above-mentioned detergents are preferably those based upon CB
to C24, more preferably those based upon Clo to Clg, alkyl and
acyl moieties.
For many embodiments of this invention, the amount of
synthetic detergent (a) may lie in the range from 10 to 50%
wt. Further preferences are at least 20% and not more than
40%.
Amongst the above synthetic detergents, some, notably acyl
isethionates are less water-soluble than others. If a
detergent of low solubility is used, it is preferably mixed
with another synthetic detergent. Thus detergent compositions
of this invention may possibly exclude acyl isethionate from
the synthetic detergent (a) or may possibly include it jointly
with other synthetic detergent. In some embodiments of this
invention acyl i:~ethionate is not more than 10% by weight of
the composition e.g. 5% to 9.5%. However, further embodiments
of the invention include larger quantities of acyl
isethionate, e.g. up to 30% by weight of the composition.
WO 94/21778 PC'TlEP94/00792
21 577 73
6
The water-soluble structurant (b) is required to melt in
the temperature range from 40°C to 100°C so that it can
be melted to form the bar composition but will be in a
solid state at temperatures at which the bar will be
used. Preferably it has a melting point of at least
50°C, notably in the narrower range from 50°C to 90°C.
Polyethylene glycols (PEG'S) which are used have a
molecular weight in the range 1500-10,000. 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 is
because their long polymer chains remain entangled even
when the bar composition is wetted during use.
If such high molecular weight polyethylene glycols
2 o are used, the quantity is preferably
from 1% to 5%, more preferably from 1% or 1.5% to 4% or
4.5% by weight of the composition. These materials will
A
WO 94/21778 PCT/EP94/00792
21 5 77 7 3
generally be used jointly with a larger quantity of
polyethylene glycol of molecular weight 1500 to 10,000.
S The water-insoluble structurants (c) are also required tc
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-
A
WO 94/21778 PCT/EP94/00792
8
~z~.~~~~3
insoluble structurants include alkanols of 8 to 20 carbon
atoms, particularly cetyl alcohol. These materials
generally have a water-solubility of less than Sg/litre
at 20°C.
The relative proportions of the water-soluble
structurants (b) and water-insoluble structurants (c)
govern the rate at which the bar wears during use. the
presence of the water-insoluble structurant tends to
delay dissolution of the bar when exposed to water daring
use and hence retard the rate of wear.
Preferably the total quantity of component (c) is from
loo t=o 40% by weight of the composition.
A wat=er-insoluble material which does not melt below
100°c, can function as an additional bar structurant. It
may be stipulated as a requirement that the content (if
any) of water-insoluble material which does not melt
below 100°C is less than 20% by weight of the
composition.
If a water-insoluble structurant (c) which does not »elt
below 100°C is present it may well be selected from ~~lant
materials or minerals. Starches, including corn starch,
are preferred amongst the plant materials while kaol_n
and calcite are preferred mineral materials. The ravio
of water-soluble structurant (b) to the total of wat~:r-
-T-i~ ___..._.. , ~_.~~a~__ i ~. _. i ~
WO 94/21778 PCT/EP94/00792
3
9
insoluble structurants may possibly lie in a range from
2:3 or 1:1 up to 3:1 or 5:1.
Some soap, that is to say salts of monocarboxylic fatty
acids having chain lengths of 8 to 22 carbon atoms may be
included in the bar compositions of this invention. The
amount is desirably not greater than loo by weight of the
composition.
We have found that if water-insoluble soap is included,
it is advantageous in reducing the wear rate of the bars.
Such water-insoluble soaps are salts of saturated fatty
acids having chain lengths of 16 to 22 carbon atoms,
especially 16 and 18. Preferably these salts are sodium
salts. They melt at temperatures above 100°C and
therefore come within a category (e) which is material,
other than synthetic detergent, melting above 100°C.
If water-insoluble soap is present in the composition,
the amount of it desirably does not exceed 10% by weight
of the composition, for example lying in a range from 30
to 9.5o by weight, more preferably 5% to 9%.
It is preferred to include a combination of polyethylene
glycol with molecular weight 50,000 to 500,000 as at
least part of the soluble structurant (b) and water-
insoluble soap as at least part of the insoluble material
(c). Use of these materials in combination has been
WO 94/21778 PCT/EP91/00792
2 ~~ 5'~'~'~ 3
found to improve wear rate of the bars, while also g=_ving
them a good feel when handled during use.
When such a combination of materials is used, the
5 preferred amounts, by weight of the composition are:
4 to 9.5% of water-insoluble soap and 1.5 to 4.5%
polyethylene glycol with molecular weight in the range
from 50,000 to 500,000.
10 Mates-ials which may be included but which do not melt. at
temperatures below 100°C can be classified as
non-soap synthetic detergent which does not
comp~~_etely liquify at temperatures below 100°C, for
example acyl isethionates;
soap, especially water-insoluble soap, which dof~s
not melt below 100°C;
other water-insoluble materials which do not me_t
below 100°C.
Mater-ials, other than synthetic detergent, which are
water--soluble but do not melt below 100°C are prefer~ibly
absent, or present only in quantities which are smal_
such as not more than 10% better not more than 5% by
weight of the composition.
It i:> desirable that the total quantity of material _n
the second and third of these categories (i.e. mater~als
other- than non-soap synthetic detergent) is not more than
20% by weight of the composition. The total quantity of
WU94.21778 2~~ ~~~3
PCT/EP94/00792
11
material which does not melt below 100°C s't_muld not exceed 50%
by weight of the composition, preferably less, such as not
more than 40% or not more than 30%, or even 20% and should not
be so much that the molten composition ceases to be stirrable.
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, e.g. lying in a range from 3% or 50
to 14.9% by weight.
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:-
skin conditioning agents, including emollients such as fatty
alcohols and vegetable oils, essential oils, waxes,
phospholipids, lanolin, anti-bacterial agents and sanitisers,
opacifiers, pearlescers, electrolytes, perfumes, suncreens,
fluorescers and colouring agents. Preferred skin conditioning
agents comprise silicone oils, mineral oils and/or glycerol.
According to a further aspect of the present invention there
is provided a process for the manufacture of synthetic
detergents bars which comprises the steps of:
(i) preparing a liquid mixture of the synthetic, non-
soap detergent, the structurants and
WO 94121778 PCT/EP9~'~/00792
12
2,15~'~~3
optionally water at a temperature of 50°C to
100°C, preferably 50°C to 90°C, said mixture
comprising less than 20%wt of material other
than synthetic non-soap detergent which dogs
not enter the molten liquid phase,
(=i) cooling the product of step (i) to a
temperature at which it solidifies, and
(~_ii) forming the product of step (i) into bars.
The ~_iquid mixture can be a single or multiple phase
system. The single phase can be an isotropic mixture
wherE:as the multiple phase system can comprise eithe_- an
emul:~ion or liquid crystal dispersion. The mixture ~:an
be prepared by mixing of the components followed by
heating of the mixture to the molten state when furt.ler
mixing will occur, or by heating of the components
folk>wed by mixing of the components.
Step (i) may be carried out in a stirred, heated vessel.
For a composition which contains fatty acid or a mix=ure
of soap and fatty acid and also contains polyalkylen~:
oxide, a useful procedure begins with melting the fa:ty
acid in a heated vessel with a stirrer. The stirrer is
started, and the polyalkylene oxide is added. At this
stage any soap is made in situ by partial neutralisa:ion
J -~ , ___ ~ ~___ [p
WO 94/21778 PCT/EP94/00792
215'773
13
of the fatty acid.
Next the non-soap detergent is added. The end result is
a macroscopically homogenous molten mixture, with not
more than 50% solids present.
Preferably step (ii) is carried out on a chilled, scraped
roller which may be part of a chilled mill.
l0 Minor ingredients and benefit agents can be added at this
stage, between steps (ii) and (iii).
Step (iii) can comprise milling, plodding and stamping,
or optional milling followed by compression of the
material into a bar shape.
In an alternative embodiment of the invention the liquid
mixture from step (i) is cast into moulds. The casting
step can be employed to form a log which is further
processed into bars or to form bars directly. Where the
product is cast into bars the process steps (ii) and
(iii) are combined; the moulds which are used can form
the final packaging of the bars or the bars can be
extracted from the moulds and re-packaged.
In order that the present invention may be further
understood it will be described with reference to the
following illustrative examples.
WO 94/21778 PCT/EP94/00792
~1~~~~3
14
EXAM PLE 1
Components as listed in Table 1 below were melted
together at 80°C to produce a material consisting
predominantly of a liquid phase. All amounts are given
in percentages by weight. On cooling to room
temperature, solid, generally cuboid bars were formed
from compositions (A) and (B) using a single bar press.
Identical compositions were also formed into bars by
using a casting process from the hot melt.
TABLE 1
A B
SLES 3E0' 21% 21%
Stearic Acid 10% 200
Cetyl alcohol l00 -
PEG 4000" 50% 50%
Water 8a 8%
Perfume to to
* SLES 3E0 denotes sodium lauryl ether sulphite
with average 3 ethylene oxide residues.
** PEG 4000 denotes polyethylene glycol with nean
molecular weight 4000.
Both the melt-cast and pressed bars had acceptable
properties for 'syndet' bars.
~ - _ q , ~ . _-~I.
WO 94/21778 PCT/EP94/00792
215'~7'~3
EXAMPLE 2
The materials listed in Table 2 below, where all amounts
are given as percentages by weight, were melted together
at 80°C to produce a pumpable, stirrable liquid. The
5 liquid melt was poured into bar shaped moulds and allowed
to cool to form solid bars, i.e. the bars were cast from
the melt. Acceptable bars were obtained.
TABLE 2
10 2A 2B 2C 2D
Aerosol OT' 21 45 25 50
PEG 4000 37 25 37.5 25
Stearic acid 37 25 37.5 25
Water 5 5 0 0
* Aerosol OT is dioctylsulphosuccinate
WO 94/21778 PCT/BP91I00792
~~~5'~ "~'~ 3
16
EXAMPLE 3
The materials listed in Table 3 below were melted
together at 80°C to produce a pumpable, stirrable li~~uid.
All amounts are given in percentages by weight. The
liqu~_d melt was cast into bars as in Example 2.
A quantity of each melt was processed into bars by a
different route. The melt was cooled by passing ove- a
chilled three-roll mill. Small quantities of perfum:,
opac-_fier and fluorescer were added, totalling less :han
2a by weight of the composition. The resulting
composition was re-milled, passed through a vacuum
plodder and stamped into the desired bar shape using a
manual press.
TABLE 3
3A 3B 3C 3D
SLE3 3E0 14 21 28 14
PEG 4000 40 35 30 53
Ste<~ric acid 40 35 30 27
Wat~'r 6 9 12 6
Acceptable bars were obtained by both processing rouses.
2 5 EXAMF?LE 4
Components as listed in Table 4 below were made into bars
by the procedure of Example 2. All amounts are given in
percentages by weight. These bars contained a mixture of
two detergent actives.
- _ ,» __.~ __...
T h ,
WO 94/21778 PCT/EP94/00792
17
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WO 94/21778
PCT'/E P94100792
21 5 77 7 3
18
EXAMPLE S
The materials listed in Table 5 below were made into bars
by the procedure of Example 2. All amounts are given in
percentages by weight. In these bars, the water-soluble
structurant was a mixture of polyethylene glycol and a
block copolymer of polyethylene oxideand polypropylene
oxide, available as PluronicTM F87, ex BASF Germany.
TABLE S
5A 5g
Aerosol OT 21 45
PEG 4000 20 20
Pluronic F87 17 5
Stearic acid 37 25
Water 5 5
A
WO 94/21778 PCT/EP94/00792
19
EXAMPLE 6
The materials listed in Table 6 below were melted together
at 80°C. All amounts are given in percentages by weight.
The PEG 4000 and stearic acid were the first materials to
be heated and melted. When these were molten, a small
quantity of sodium hydroxide was added to neutralise a
little of the stearic acid to sodium stearate. After this
the remaining materials were added and stirred to produce
a pumpable, homogeneous liquid.
Each melt was cooled by passing over a chilled three-
roll mill. to of perfume, and 0.3% of titanium dioxide as
opacifier were then added, followed by milling and
plodding the resulting composition and stamped into the
desired bar shape using a manual press.
TABLE 6
6A 6B 6C 6D
SLES 3E0 11 11 10 10
DEFI 18 33 20 20
CAPB 1 5 1 1
PEG 4000 35 25 36 36
PEG 100,000 4 4 0 8
Stearic acid 22 13 20 20
Sodium stearate 4 4 8 0
Water 5 5 5 5
WO 94/21778 PCT/EP9< </00792
21~~~'~3
EXAMPhE 7
The materials listed in Table 7 below were made into ears
by the procedure of Example 3 in which the melt was cooled
on a mill, plodded and stamped info bars. All quantities
5 are given as percentages by weight. These bars conta=ned
a mixture of three detergent actives.
TABLE 7
7A 7B 7C 7D 7E 7F
SLES 3E0 10 9.56 9.22 10.42 9.96 9.6
DEFI 17 16.2 15.68 31.26 29.87 28.83
CAPB 1 0.96 0.92 4.72 4.53 4.37
PEG x:000 33 31.53 30.43 23.68 22.63 21.8
PEG 7_00,000 4 3.82 3.69 3.8 3.62 3.5
Stear-ic acid 21 20.1 19.37 12.32 11.77 11.3
Sodium 4 3.82 3.69 3.8 3.62 3.5
steaz-ate
Water 10 14 17 10 14 17
Compositions 7C and 7F gave compositions which were tc~o
soft to process whereas the remaining compositions coi.ld
be prccessed into firm bars.
~ n ____ , ~ _ ~I
WO 94/21778
PCT/EP94/00792
21
Example 8
A number of compositions from the preceding examples were
assessed for mildness using a zein test generally as
described by Gatte, Proc. Int. Cong. Surface Active Subs.,
4th, Brussels, 3, 89-90 (1964) . The test determines the
amount of amino acid solubilised from zein under specified
conditions. The solubilised material is determined by a
nitrogen assay. The results were as follows.
Composition number - Solubilised nitrogen
3A 0.08
3B 0.13
3C 0.16
4D 0.11
4G 0.1
4K 0.11
6A 0.12
6C 0.05
6D 0.05
7D 0.2
80/20 coconut/tallow soap 0.73
'DOVE' commercial 0.22
'syndet'bar based on DEFI
The low values of zein solubilisation for the bars of this
invention indicate very good mildness.
