Note: Descriptions are shown in the official language in which they were submitted.
WO91/1~8 PCT/EP91/~259
2a73~6~
LIOUID BLEACH COMPOSITION
The present invention relates to a liquid detergent
composition comprising an aqueous base, detergent active
materials and a bleach material.
EP 294 904 (P&G) discloses the use of perborate bleach
materials in liquid detergent compositions, whereby the
bleach materials are present in the form of particles
having a weight average particle diameter of from 0.5 to
20 micrometer and whereby said particles being formed by
in situ crystallization. A problem in using these small
particles is that they require a laborous mixing
process, said process often requiring a vigorous mixing
step which may lead to moussing of the product.
Furthermore these small particles may sometimes be prone
to instability due to their relatively large surface
area. Also liquid detergent compositions containing
these small particles sometimes suffer from high
viscosities.
EP 368 575 (ICI) relates to suspensions of perborate and
thickening agents for incorporation into liquid
detergent compositions. A problem in using suspensions
of bleach materials for the preparation of liquid
detergents is that the presence of an aqueous phase in
the suspension leads to the dilution of the detergent
composition, especially for concentrated liquid
detergent compositions. Such a dilution step is often
not desirable. Furthermore the use of pre-suspensions of
bleach materials leads to an extra processing and/or
transporting step for preparing and/or transporting the
suspension, generally this results in a cost increase
for the liquid detergent composition.
2 0 7 3 ~ 6 3 PCT/EP91/~9
Surprisingly it has now been found that one or more of
the above mentioned problems can be solved and stable
bleach con~ining liquid detergent compositions can be
obtained by the in-situ formation of bleach particles
having a weight average particle size of more than 20
micrometer.
Accordingly the present invention relates to a method
for the preparation of a liguid detergent composition
comprising an aqueous phase, one or more detergent
active materials and a bleach material, said method
comprising the in-situ formation of bleach particles
having a weight average particle size of more than 20
micrometer.
A further aspect of the invention is that if the bleach
particles having a weight average particle size of more
than 20 micrometer are formed in situ, this allows the
preparation of liquid detergent compositions which
comprise relatively low amounts of water (say less than
50 % by weight, more preferably less than 40 % by
weight, more preferably from 10 to 35 %) in combination
with relatively high amount of detergent active
materials (say more than 15 % by weight, more preferably
more than 20 ~, most preferably from 25 to 60 %) and
relatively high amounts of bleach materials (say more
than 1 %, more preferred more than 7 %, most preferred
from 10 to 50 %).
Accordingly the invention also relates to a liquid
detergent composition comprising less than 50 % by
weight of water, more than 15 % of detergent active
materials and more than 1 % by weight of bleach
material, said bleach material having a weight average
particle size of more than 20 micrometer.
WO91/12~ PCT/EP91/~259
~ 3 20~3~
bleach material
Compositions according to the present invention
comprise a bleach material, which is preferably a
~e~oxyyen bleach. This bleach component is present in
the system at least partly in llnAi~colved form, but
generally at least a minor part of the peroxygen bleach
will be solubilized. The solid particles will generally
be cl~r~n~ed in the system.
Examples of suitable bleach compounds include the
~e~o -tes, persulfates, peroxy ~ llfates~
calcium~e.~xi~c, perphosphates and the crystalline
pero~yhy~ates formed by reacting hydrogen peroxide with
urea or ~ 1 kA l; metal carbonate. Also ~nc~pculated
bleaches may be used. Especially preferred is the use of
perborate or percarbonate bleaches.
Typical amounts of bleach will be between 1 and 50 % by
weight of the aqueous composition, more preferred from 7
to 30 %, especially preferred from 10 to 25 % by weight
of the composition.
The weight average particle size of the bleach particles
is more than 20 micrometer, preferably from 22-150
micrometer, more preferably from 25 to 60 micrometer,
most preferably from 30 to 50 or 45 micrometer. A
suitable method for determining the weight average
particle size involves the making of microscopy pictures
of the liquid detergent composition at a magnification
of between 50 and 600 (preferably about 150), followed
by the manual or automatic counting of the visible
particles, measuring the particle diameter for each
particle and calculating the weight average particle
size for the visible particles.
W091/12~ PCT/EP9l/~t~9
2073~6~ 4
Sometimes the bleach material will be s~r~n~ed in the
system as agglomerates of small elementary bleach
particles. Since it is believed that normally the size
of the agglomerates rather than the size of the
elementary bleach particles determines the
characteristics of the final product, for the ~u~ose of
the invention, the bleach particle size refers to the
weight average particle size of these agglomerates. If
agglomerates of bleach particles are ~ e_cnt, for
determining the particle size, care has to be taken not
to subject the measuring sample to l~nn~c~cs~ry shear or
pressure, because this may lead to the fragmentation of
the agglomerates.
detergent active materials
Compositions of the present invention also comprise
detergent active materials. Surprisingly it has been
found that physically stable bleach containing liquid
detergent compositions can be obtAine~ by the in-situ
formation of bleach particles having a weight average
particle size of more than 20 micrometer.
In the widest definition the detergent active materials
in general, may comprise one or more surfactants, and
may be selected from anionic, cationic, nonionic,
zwitterionic and amphoteric species, and (provided
mutually compatible) mixtures thereof. For example, they
may be chosen from any of the classes, sub-classes and
specific materials described in "Surface Active Agents~
Vol. I, by Schwartz & Perry, Interscience 1949 and
"Surface Active Agents" Vol. II by Schwartz, Perry &
Berch (Interscience 1958), in the current edition of
"McCutcheon's Emulsifiers & Detergentsl' published by the
McCutcheon division of Manufacturing Confectioners
Company or in Tensid-Taschenburch", H. Stache, 2nd Edn.,
Carl Hanser Verlag, Munchen & Wien, 1981.
WO91/12~8 PCT/EP91/~259
2073~63
Suitable nonionic surfactants include, in particular,
the reaction products of compolln~C having a hydrophobic
group and a reactive hyJ~oyen atom, for example
aliphatic alcohols, acids, amides or alkyl phenols with
alkylene oxides, ~-recially ethylene oxide either alone
or with ~ o~lene oxide. Specific nonionic detergent
com~o~ c are alkyl (C6-C18) primary or c~con~A-y
lin~Ar or brAnc~~~ alcohols with ethylene oxide, and
products made by ~onA~cAtion of ethylene oxide with the
reaction products of propylene oxide and
ethylenediamine. Other so-called nonionic detergent
compo~AC include long chain tertiary amine oxides, long
chain tertiary r~n~rh i n~ oxides and dialkyl sulphoxides.
Also possible is the use of salting out resistant active
materials, such as for example described in EP 328 177,
especially the use of alkyl poly glycoside surfactants,
such as for example disclosed in EP 70 07~.
Suitable anionic surfactants are usually water-soluble
alkali metal salts of organic sulphates and sulphonates
having alkyl radicals contAining from about 8 to about
22 carbon atoms, the term alkyl being used to include
the alkyl portion of higher acyl radicals. Examples of
suitable synthetic anionic detergent compounds are
sodium and potassium alkyl sulphates, especially those
obtained by sulphating higher (C8-C18) alcohols produced
for example from tallow or coconut oil, sodium and
potassium alkyl (Cg-C20) benzene sulphonates,
particularly sodium linear secondary alkyl (C10-C15)
benzene sulphonates; sodium alkyl glyceryl ether
sulphates, especially those ethers of the higher
alcohols derived from tallow or coconut oil and
synthetic alcohols derived from petroleum; sodium
cG~o-.~L oil fatty monoglyceride slllph~tes and
sulphonates; sodium and potassium salts of sulphuric
acid esters of higher (C8-C18) fatty alcohol-alkylene
W091/12~
PCI~/EP91/00'~9
2073S6~ 6 _ ~
oxide, particularly ethylene oxide, reaction products;
the reaction products of fatty acids such as coconut
fatty acids esterified with isethionic acid and
neutr~ ed with sodium hydroxide; sodium and potassium
salts of fatty acid amides of methyl taurine; alkane
monoc~lphonates such as those derived by reacting alpha-
olefins (C8-C20) with sodium bisulphite and those
derived from reacting paraffins with S02 and C12 and
then hydrolysing with a base to produce a random
r~lrQ~te; and olefin ~ r~onates~ which term is used to
describe the material made by reacting olefins,
Particularly C10-C20 alpha-olefins, with S03 and then
neutralising and hydrolysing the reaction product. The
preferred anionic detergent compounds are sodium (Cl1-
C15) alkyl benzene ~ulrho~tes and sodium or potassiumprimary (C10-cl8) alkyl sulphates.
It is also possible, and sometimes preferred, to include
an Alk~li metal soap of a fatty acid, especially a soap
of an acid having from 12 to 18 carbon atoms, for
example oleic acid, ricinoleic acid, and fatty acids
derived from castor oil, alkylsuccinic acid, rapeseed
oil, glo~ oil, CG~Ol-u- oil, palmkernel oil or
mi~Lures thereof. The sodium or potassium soaps of these
acids can be used.
The total detergent active material may be present at
from 15% to 70% by weight of the total composition, for
example from 20% to 60% and typically from 30% to 50~ by
weight.
oPtional ingredients
Compositions of the invention may be un-structured
(isotropic) but are preferably structured. Structured
liquids of the invention may be internally structured
whereby the structure is formed by the detergent active
materials in the composition or externally structured,
WO91/12~8 PCT/EP91/~ ~9
2~ 73~S3
whereby the structure is provided by an external
structurant. Preferably compositions of the invention
are internally stru~u ed. Most preferably compositions
of the invention comprise a surfactant structure
comprising lamellar droplets of detergent active
materials.
Some of the different kinds of active-structuring which
are possible are described in the reference H.A. Barnes,
"Detergents", Ch.2. in K. Walters (Ed), "Rheometry:
Industrial Applications", J. Wiley & Sons, Letchworth
1980. In general, the degree of ordering of such systems
increases with increasing surfactant and/or electrolyte
con~ ations. At very low concentrations, the
surfactant can exist as a mol~cnlAr solution, or as a
solution of spherical micelles, both of these being
isotropic. With the addition of further surfactant
and/or electrolyte, structured (antisotropic) systems
can form. They are referred to respectively, by various
terms such as rod-micelles, planar lamellar structures,
lamellar droplets and liquid cryst~l 1;ne ph~es. Often,
different workers have used different terminology to
refer to the structures which are really the same. For
instance, in E~ o~ean patent specification EP-A-151
884, lamellar droplets are called Uspherulites''. The
presence and identity of a surfactant structuring system
in a liquid may be determined by means known to those
skilled in the art for example, optical terhniques,
various rheometrical measurements, x-ray or neutron
diffraction, and sometimes, electron microscopy.
When the compositions are of lamellar droplet structure
then in many cases it is preferred for the aqueous
continuous phase to contain dissolved electrolyte. As
used herein, the term electrolyte means any ionic water
soluble material. However, in lamellar dispersions, not
all the electrolyte is nececs~rily dissolved but may be
suspended as particles of solid because the total
WO91/1~8
PCT/EP91/~2~g
electrol~Q concentration of the liquid is higher than
the solubility limit of the electrolyte. Mixtures of
electrolytes also may be used, with one or more of the
electrolytes being in the dissolved aqueous phase and
one or more being substantially only in the suspended
solid phase. Two or more electrolytes may also be
distributed approximately ~-o~o~Lionally, between these
two r~ces. In part, this may depend on processing, e.g.
the order of addition of components. On the other hand,
the term "salts" includes all organic and inorganic
materials which may be included, other than surfactants
and water, whether or not they are ionic, and this term
enComp~c~ec the sub-set of the electrolytes (water
soluble materials).
The selection of surfactant types and their proportions,
in order to obtain a stable liquid with the required
structure will be fully within the capability of those
skilled in the art. However, it can be mentioned that an
important sub-class of useful compositions is those
where the detergent active material comprises blends of
different surfactant types. Typical blends usefu~ for
fa~ric w~chi n~ compositions include those where the
primary surfactant(s) comprise nonionic and/or a non-
alkoxylated anionic and/or an alkoxylated anionicsurfactant.
In the case of blends of surfactants, the precise
proportions of each component which will result in such
stability and viscosity will depend on the type(s) and
amount(s) of the electrolytes, as is the case with
conventional structured liquids.
Preferably though, the compositions contain from 1% to
60%, especially from l0 to 45% of a salting-out
electrolyte. Salting-out electrolyte has the meAning
ascribed to in specification EP-A-79 646, that is
salting-out electrolytes have a lyotropic number of less
WO91/1~8 PCT/EP91/~259
9 2073~63
than 9.5. Optionally, some salting-in electrolyte (as
defined in the latter specification) may also be
included, provided it is of a kind and in an amount
compatible with the other components and the composition
is still in accordance with the definition of the
invention claimed herein. Some or all of the electrolyte
(whether salting-in or salting-out), or any
substantially water insoluble salt which may be present,
may have detergency builder properties. In any event, it
is preferred that compositions according to the present
invention include detergency builder material, some or
all of which may be electrolyte. The builder material is
any capable of reducing the level of free calcium ions
in the wash liquor and will preferably provide the
composition with other beneficial properties such as the
generation of an alkaline pH, the suspension of soil
removed from the fabric and the dispersion of the fabric
softening clay material. Preferably the salting-out
electrolyte comprises citrate.
Examples of rhscrhorus-cont~i ni ng inorganic detergency
h~ ers, when ~ ~ nt, include the water-soluble salts,
especially ~l ~A li metal pyrorhoRrhAtes, orthophosphates,
polyphosphates and phosp~o~tes. Specific examples of
inorganic p~rh~te builders include sodium and
potassium tripolyphosphates, phosphates and
hexametaphosphates. Phosphonate sequestrant builders may
also be used.
Examples of non-phosphorus-containing inorganic
detergency builders, when present, include water-
soluble alkali metal carbonates, bicarbonates, silicates
and crystalline and amorphous aluminosilicates. Specific
examples include sodium carbonate (with or without
calcite seeds), potassium carbonate, sodium and
potassium bicarbonates, silicates and zeolites.
Examples of organic detergency builders, when present,
wo gl/l2~8 2 0 ~ 3 5 6 ~ PCT/EP91/~9
~- '
include the alk~line metal, ammonium and substituted
ammonium polyacetates, carboxylates, polycarboxylates,
polyacetyl carboxylates and polyhy~ox~sulphonates.
Specific examples include sodium, potassium, lithium,
ammonium and substituted ammonium salts of
ethylen~ minetetraacetic acid, nitrilitriacetic acid,
oxydisuccinic acid, CMOS, TMS, TDS, melitic acid,
benzene polycarboxylic acids and citric acid.
Preferably the level of non-soap builder material is
from 0-50% by weight of the composition, more preferred
from 5-40%, most preferred 10-35%.
In the context of organic builders, it is also desirable
to in~o~v~ate polymers which are only partly dissolved,
in the aqueous continuous phase as described in EP
301.882. This allows a viscosity reduction (due to the
polymer which is dissolved) whilst incorporating a
sufficiently high amount to achieve a ~econ~ry benefit,
especially building, because the part which is not
dissolved does not bring about the instability that
would occur if substantially all were dissolved. Typical
amounts are from 0.5 to 4.5% by weight.
It is further possible to include in the compositions of
the present invention, alternatively, or in addition to
the partly dissolved polymer, yet another polymer which
is substantially totally soluble in the aqueous phase
and has an electrolyte resistance of more than 5 grams
sodium nitrilotriacetate in lOOml of a 5% by weight
aqueous solution of the polymer, said second polymer
also having a vapour pressure in 20% aqueous solution,
equal to or less than the vapour pressure of a reference
2% by weight or greater aqueous solution of polyethylene
glycol having an average molec~ r weight of 6000; said
second polymer having a molecular weight of at least
1000. Use of such polymers is generally described in our
EP 301,883. Typical levels are from 0.5 to 4.5% by
WO91/12~8 PCT/EP91/~25g
~ 11 2~73~
weight.
The viscosity of compositions according to the present
is preferably less than 2,500 mPa.s, more preferred less
than 2,000 mPa.s, most preferred less than 1,500 mPa.s,
especially preferred between 30 and 900 mPa.s at 21 s-
One way of regulating the viscosity and stability ofcompositions according to the present invention is to
include viscosity regulating polymeric materials.
Viscosity and/or stability regulating polymers which are
preferred for incorporation in compositions according to
the invention include deflocculating polymers having a
11Y~L o~hilic backbone and at least one h~d~u~hobic side
chain. Such polymers are for instance described in our
copending European application EP 89201530.6
(EP 346 995). Preferably the amount of viscosity
regulating polymer is from 0.1 to 5% by weight of the
total composition, more preferred from 0.2 to 2%.
Compositions of the invention may also comprise
materials for adjusting the pH. For lowering the pH it
is preferred to use weak acids, especially the use of
organic acids is preferred, more preferred is the use of
C 1-8 carboxylic acids, most preferred is the use of
citric acid. The use of these pH lowering agents is
especially preferred when the compositions of the
invention contain enzymes such as amylases, proteases
and lipolases.
Apart from the ingredients already mentioned, a number
of optional ingredients may also be present, for example
lather boosters such as alkanolamides, particularly the
monoethanolamides derived from palm kernel fatty acids
and coconut fatty acids, fabric softeners such as clays,
amines and amine oxides, lather depressants, inorganic
salts such as sodium sulphate, and, usually present in
12
~ very minor amounts, fluorescent agents, perfumes,
germicides colourants and enzymes such as proteases,
cellulases, amylases and lipases (including Lipolase
(Trade Mark) ex Novo). Suitable examples of protease
enzymes are Savinase~ (ex Novo), Maxacal~ (Gist-
Brocades), Opticlean~ (ex MKC) or AP122~ (ex Showa
Denko), Alcalase~, Maxatase~, Esperase~, Optimase~,
proteinase K and subtilisin BPN. Suitable lipases are
for example Lipolase~ (ex Novo), Amano lipases, Meito
lipases, Lipozym~, SP 225, SP 285, Toyo Jozo lipase.-
Suitable amylases are for example Termamyl~ (TM of Novo)
and Maxamyl~. Suitable cellulases include Celluzym~ (ex
Novo).
Compositions of the invention preferably comprise from
5-50 % by weight of water, more preferably from 10-45%,
most preferably from 15-35 %.
Liquid detergent compositions according to the invention
are preferably physically stable in that they show less
than 2% by volume phase separation upon storage for 21
days after preparation at 25~C.
Liquid detergent compositions according to the invention
are preferably volume stable in that they show less than
25% preferably less than 10%, more preferably less than
5% volume increase during storage at a temperature
between 20 and 37~C for a period of three months after
preparation.
Also preferably compositions according to the invention
have solid suspending properties, most preferably they
do not yield any visible sedimentation after storage for
three weeks at 21~C.
Compositions of the present invention may comprise one
or more bleach precursor agents. A well-known example of
such an agent is TAED. Preferably the bleach precursor
agent is present in the system in at least partly
~ST9~ T
~VO 91/12308 2 ~ 7 3 ~ 5 ~ pcr/Ep9l~oo2s9
13
-n~i c~Qlved form. One way of ensuring that the precursor
is present in ll~i s~olved form is to increase the amount
of electrolyte in the composition, therewith reducing
the solubility of the precursor in the system. Suitable
electrolytes for this ~L~Gsc are for instance the at
least partially water soluble carbonate, c~lrh~te and
halogenide salts.
Compositions of the invention may also advantageously
comprise one or more ingredients for the stabilization
of bleach materials. Suitable materials are for example
metaborate electrolytes and magnesium salts.
In use the detergent compositions of the invention will
be diluted with wash water to form a wash liquor for
instance for use in a washing machine. The
conc~ntration of liquid detergent composition in the
wash liquor is preferably from 0.05 to 10 %, more
preferred from 0.1 to 3% by weight.
To ensure effective detergency, the liquid detergent
compositions preferably are alkaline, and it is
preferred that they should provide a pH within the range
of about 7.0 to 12, preferably about 8 to about 11, when
used in aqueous solutions of the composition at the
recommended concentration. To meet this requirement, the
undiluted liquid composition should preferably be of a
pH above 7, for example about pH 8.0 to about 12.5. It
should be noted that an excessively high pH, e.g. over
about pH 13, is less desirable for domestic safety.
One aspect of the invention is a process for the
preparation of liquid bleach cont~;ning compositions,
said process involving the in-situ formation of bleach
particles having a weight average particle size of more
than 20 micrometer. The in-situ formation of bleach
particles relates to process~s whereby the bleach
particles such as present in the final composition, have
wo gl/12~ ~ o 7 3 ~ ~ 3 14 PCT/EP91/~'9
been formed in-situ, for example by a dissolution/
recrystallization ~Gcess or the hydration of perborate
monohydrate. It is believed to be well within the
ability of the skilled person to adapt the processing
conditions such that the required particle sizes are
obtained. Preferred parameters to be varied for
ob~Aini~ the desired particles sizes are physical form
of the bleach materials that are added to the
composition, stirring conditions and order of addition.
When the bleach material is a perborate bleach material,
preferably the bleach is added as perboratemonohydrate,
which will be formed into perborate tetrahydrate in the
composition. Another preferred method of bleach
incorporation is the use of a combination of hydrogen
peroxide and a borate material, which will in-situ react
to form a peLbO~ ate bleach. A preferred borate material
is metaborate.
It is preferred that the bleach materials are added into
the composition under mild stirring conditions,
preferably less than 10 c/s, more preferably less than
5 c/s, most preferably from 0.2 to 3 c/s. The tip-speed
of the stirrer is preferably 0.01-10 m/s, more
preferably 0.1 to 5 m/s, most preferred 0.5 to 2 m/s.
A preferred order of addition involves the addition of
electrolyte non-bleach materials to water of elevated
temperature, followed by the addition of detergent
active materials, the bleach material and the remaining
ingredients.
The invention will now be illustrated by way of the
following Examples. In all Examples, unless stated to
the contrary, all percentages are by weight.
ExamPle I
The following composition can be prepared by adding the
citrate/citric acid and the polymer to water at elevated
temperature, followed by addition of the detergent
active materials as a premix and the bleach material.
Ingredient ~ wt
ABS 21
Synperonic~ A7 9
citrate/citric acidl) 10
bleach 15
polymer2 )
metaborate 2.6
water balance
1) mixture used to adjust pH to 8.5
2) polymer A-11 as described in EP 346 995
The composition can be prepared several times on a 1 kg
scale in a 2 litre glass with a 6 blade stirrer having a
diameter of 8 cm, while the type of bleach and the
stirring conditions are varied as follows:
~ stirring type of
ExPeriment rate in c/s bleach
I 0.2 perboratemonohydrate
II 1.0 "
III 5 "
30 IV 10 "
V 0.2 H202/sodiumborate3)
VI 1.0 "
VII 5 "
VIII 10 "
35 IX 1.0 perborate tetrahydrate
3) ratios chosen such that perborate tetrahydrate is
formed in-situ.
t~ ;3h~
WO gl/12308 2 ~ 7 3 ~ ~ ~ PCr/EPgl/OO~9
16 ~ -
Each of the compositions can be stored for 24 hours at
ambient temperature and microscopy pi~ e_ can be taken
at a magnification of 150 times. The weight average
S particle size of the bleach materials is determined by
counting the visible particles. The physical stability,
the volume stability and the solid suspen~ing properties
of the composition are determined.
17 2 ~ 7 ~
ExamPle II
The following compositions were made by adding the
citric acid/citrate to water, followed by the addition
of the sodium metaborate, sodium hydroxide for
neutralising the detergent active materials, the
polymer, a premix of the detergent active materials in
acid form the minor ingredients and the hydrogen
peroxide or the perborate monohydrate.
INGREDIENT (wt parts) A B C D
Na-Dobs 21 21 21 21
Synperonic~ A7 9 9 9 9
citrate/citric acid 10 10 15 15
perboratemonohydrate 15 - 15
metaborate/H2O2 - 15 _ 15
polymer
sodium metaborate 2.6 2.6 2.6 2.6
antifoam/dye 0.5 0.5 0.5 0.5
water <--up to 95--> <--up to 100-->
Notes:
- Na-Dobs is sodium dodecylbenzene sulfonate (Marlon~
AS3 neutralized with NaOH).
_ Synperonic~ A7 is a C13_15 fatty alcohol with on
average 7 EO groups per molecule ex ICI.
- A mixture of citrate/citric acid is used to obtain
a final pH of the product of 9.
- Metaborate/H2O2 refers to sodium metaborate and
H202 in ratios such that 15 parts of perborate
tetrahydrate can be formed in situ.
- The polymer is a deflocculating polymer as
described in EP 346 995 as polymer A-44.
- The 2.6 parts sodium metaborate are added in
addition to the metaborate used for the formation
of perborate.
WO91/12~ PCT/EP91/~9
' ~o7 3~6~ 18 ~~ ~
Each of the formulation was prepared on a 1 kg scale in
a 2 litre glass with a 6 blade stirrer having a diameter
of 8 cm. The stirring conditions were varied as
indicated below. The particle size of the bleach was
determined by applying a thin film of the product under
moderate pressure onto a microscopy glass plate followed
by the making of a microscopy picture at a magnification
of about 400, whereafter the weight average particle
size was -roughly- determined by counting the course
fraction of the visible particles and measuring their
particle size. In most of the samples the bleach was
present in the form of agglomerates consisting of small
elementary bleach particles. In the table below the
average particle sizes of the agglomerates is given.
The following table indicates the weight average
particle size in micron of the bleach in the formulation
as a function of stirring rate.:
COMPOSITION/RATE OF STIRRING 10 C/s 5 C/s 2 C/s
A 30 35 --
B 60 100 --
C -- 60 30
D -- 120 50
19
6 ~
ExamPle III
The following compositions were prepared by adding the
electrolyte together with the minor ingredients except
for the perfume and the enzymes to water of elevated
temperature, followed by the addition of the detergent
active material as a premix under stirring and
thereafter cooling the mixture and adding the enzymes,
perfumes and the bleach.
INGREDIENT (% WT~ A B
Na-Dobs 23.3 21
Synperonic~ A7 10 9
Glycerol 3.9 --
Metaborate 2.9 2.6
Nacitrate/Citric acid1)11.19.8
Dequest~ 2060S (as 100%)0.40.4
Na-perborate monohydrate7.2 10
Enzyme, Alcalase~ 0.8 0.8
CaCl2.2H20 0.2 0.2
Fluorescer, Tinopal~ CBSX 0.1 0.1
Silicon, Dow Corning DB100 0.3 0.3
Perfume 0.3 0.3
Deflocculating polymer 4) 1.1
Water --- balance ---
pH 9 9
l) This mixture is used to adjust the final pH.~0 2) Expressed as % of analyzed enzyme level in the
fresh sample.
3) Deflocculating polymer of formula I of EP 346995
wherein X=50, Y=0, R5=H, Rl= -C0-0, R2 and R3 are
absent, R4- -C12H25, MW=7,500.~5 4) wt% -approximate- of total perborate, obtained by
removal of the undissolved bleach particles by mild
centrifugation.
5 ) not measured
WO91/12~8 PCT/EP91/~9
2~73~63 20
The obtained product had the following characteristics:
A B
5 Volume stability (% volume 0 o
increase, 3 months 25~C)
clear layer separation no no
(3 weeks 37~C)
solid sedimentation no no
10 (3 weeks 37~C)
Viscosity 21 s-1 800 760
Dissolved perborates 5) 8 6
Bleach activity 96 97
(2 months ambient T)
15 enzyme activity 76 n.m.S)
(2 months ambient T)2)
