Note: Descriptions are shown in the official language in which they were submitted.
~a~36%
Homogeneous aqueous formulations
The present invention relates to new, homogeneous
aqueous formulations of agrochemical active compounds,
active compounds for combating pests in the domestic and
hygiene sectors and/or pharmacologically active compounds.
The invention also relates to a process for the prepar-
ation of these homogeneous aqueous formulations and to
their use.
Aqueous emulsions of numerous agrochemical act-
ive compounds of low solubility in water which, in
addition to the active compounds, also contain, in each
case, either a surface-active substance and a thickener
or else a relatively large quantity of surface-active
substances, are already known (compare DE-A (German
Pub~ished Specification) 3,009,944, DE-A (German Pub-
lished Specification) 3,011,611 and JP-A (Japanese Pub-
lished Specification 122,628-77). m is addition of
thickeners or large quantities of surfactant is associ-
ated with additional expense and thus constitutes a
serious disadvantage of the known aqueous emulsions.
In addition to this, the preparation of emulsions of
this type which has been described hitherto is not
generally applicable. This is because, essentially it
is only possible t~ emulsify thereby active compounds
of low solubility in water which are liquid at room
temperature or at least have a very low melting point.
A further disadvantage is that the kno~n aqueous emulsions
frequently are not adequately stable under cold condi-
tions and that, in some cases, forced emulsification
using homogenisers is required.
Furthermore, concentrates, of pesticidal active
compounds9 which are dispersible in water and which, in
addition to the particular active compound, only contain
one or more emulsifiers and also, if appropriate, a
small quantity of organic solvents, have already been
Le A 21 930-Foreign countries
i~ ~,,,
93g;~
disclosed (compare US-A (US Pa~ent Specification) 3,683,078). A
considerable disadvantage of these formulations consists in the
fact that relatively large quantit-ies of emulsifier have to be
employed, above all at low contents of active compound. In
addition, the viscosity of concentrates of this type is relatively
high, so that accurate metering is difficult.
~ew, homogeneous aqueous formulations have now been
found, and the invention provides a homogeneous aqueous
composition comprising:
a) 0.01 to 50 percent by weight of at least one agrochemi-
cally active compound, one active compound for combating
pests in the household and hygiene sectors and/or one
pharmacologically active compound, which is resistant to
hydrolysis in the presence of water, inert to cyclo-
hexanone and of low solubility in water,
b) 0.1 to 25 percent by weight of at least one alkylaryl
polyglycol ether of the formula
R2
(Rl ~ )m ~ -(C2H4) H ~I)
wherein
Rl represents hydrogen or alkyl ha~ing 1 to 16 carbon atoms,
R2 represents hydrogen or methyl,
m represents numbers from 1 to 3 and
n represents numbers from 10 to 50
in admixture with an alkylaryl sulfonic acid salt of the formula
~2~9362
R ~ S0 ~ Me ~ (II)
in which
R3 represents alkyl having 8 to 35 carbon atoms and
Me ~ represents an alkali metal cation or a cation of the
formula
R"
R' - N - R"'
RIV
wherein
R', R", and R'l' and RIV independently of one another
represent hydrogen, alkyl having 1 to 4 carbon atoms or
hydroxyalkyl having 1 to 4 carbon atoms,
c) 0.1 to 30 percent by weight of cyclohexanone, and
d) water and
if appropriate, 0.05 to 15~ by weight of additives,
the total of the components amounting in each case to 100% by
weight.
It has also been found that the homogeneous aqueous
formulations according to the invention can be prepared by mixing,
by stirring at temperatures between 10C and 100C,
at least one agrochemical active compound of low solubility
in water, one active compound for combating pests in the
household and hygiene sectors and/or one pharmacoloyically
active compound,
at least one alkylaryl polyglycol ether of the formula
-- 3 --
:lZ~9;~2:
R2
(Rl ~ CH ) ~ O-(C2H40) H (I)
m
in which
Rl, R2, m and n have the meaning indicated above, if appro-
priate as a mixture with alkylarylsulphonic acid salts of the
formula
R3 ~ SO ~ Me ~ (II)
- 3a -
12~3~;~
in which
R3 and Me~ have the meaning indicated above,
- cyclohexanone and water and also, if appropriate,
additives,
5 and, if appropriate, subsequently adjusting the pH to a
value from 2 to lO by adding aqueous acid or aqueous base.
Finally, it has been found that the homogeneous
aqueous formulations according to the invention can be
used, depending on the active compounds they contain,
10 for various purposes in agriculture and horticulture, in
the household and hygiene sectors or in the medicinal
sec-tor.
It must be described as extremely surprising that
the homogeneous aqueous formulations according to the
15 invention are stable, since it would have been expected,
on the basis of the known state of the art 9 that formul-
ations of this type, cont~i ni ng no thickeners and also
only a small proportion of surfactant, would not be
stable for a prolonged period. Thus it is apparent from
20 DE-A (German Published Specification) 3,009,944 and DE-A
(German Published Specification) 3,011,611 that the
aqueous emulsions described in those publications neces-
sarily contain a thickener as a stabiliser. The emul-
sions disclosed in JP-A (Japanes~ Published Specification)
25 122,628-77 and the water-dispersible concentrates repor-
ted in US-A (US Patent Specification) 3,683,078 have
a very high proportion o~ surfactant in relation to the
quantity of active compound. The excellent stability of
the formulations according to the invention could, there-
30 fore, not have been foreseen. It is also surprising that,in contrast with corresponding emulsions or dispersions
known hitherto, the homogeneous aqueous formulations
according to the invention are completely transparent
preparations which cannot be distinguished optically
35 from true solutions.
The formulations according to the invention are
Le A 21 930
93~;Z
5 --
dis-tinguished by a number of advantages. Thus the expen-
sive addition of thickeners or of quantities of emulsi-
fiers which are large in relation to the active compound
is unnecessary in their preparation. Furthermore, the
5 formulations according to the invention are stable under
the conditions prevailing in practice. When stored for
long periods, these formulations remain unchanged both at
temperatures up to 100C and at low temperatures. In
addition7 the formulations according to the invention
10 can be prepared in a simple manner. Forced dispersion
using homogenisers is not required. On the contrary, the
formulations are obtained directly in the form of com-
pletely transparent liquids which exhibi-t no creaming up
or stratification (phase separation) even after prolonged
15 storage at high or low temperatures The formulations
according to the invention can, therefore, be used with-
out prior shaking. In addition, a very considerable
advantage consists in the fact that substances of low
solubility in water which are solid or liquid at room
20 temperature can be dispersed equally easily. Finally,
the formulati~ns according to the invention have a low
viscosity, so that accurate metering of the quantity
required in a particular case presents no difficulties.
The homogeneous aqueous formulations according
25 to the invention contain at least one agrochemical act-
ive compound of low solubility in water or at least one
active compound for combating pests in the household and
hygiene sectors and/or at least one pharmacologically active
compound. These active compounds are present in the
30 liquid state in the formulation.
Suitable active compounds are substances which
are liquid at room temperature as well as those which
are solid at room temperature. The only requirement is
that the active compounds to be dispersed do not undergo
35 hydrolysis in the presence ofwater, do not react with
cyclohexanone and, in addition, have a low solubility in
Le A 21 930
3~;2
water
Substances of this type, of low solubility in
water, are -to be understood in -the present context as
meaning substances which are soluble in wa-ter at 20c to
5 the exten-t of not m~re than 0.5 % by weight. Solid
active compounds must, however, additionally be adequately
soluble in cyclohexanone and/or emulsifier in the formul-
ation.
Agrochemical substances are to be understood,
10 in the present case, as meaning any active compounds
which can customarily be used in plant protection. These
include, for example, insecticides, acaricides, nemato-
cides, fungicides, herbicides, growth regulators and
Iertilisers. The following may be mentioned as indi~i-
15 dual examples of active compounds of this type: 0,0-di-
ethyl 0-(4-nitrophenyl) thionophosphate, 0,0-dimethyl
0-(4-nitrophenyl) thionophosphate, O~ethy~ 0-(4-methyl-
thiophenyl) S-propyl dithiophosphate, (0,0-diethylthiono-
phosphoryl)-a-o~i m; nophenylacetonitrile~ 2-isopropoxy-
20 phenyl N-methylcarbamate, 3-methylthio-4~amino-6-tert.-
butyl-1,2,4-triazin-5-one, 3-methylthio-4-isobutylidene-
amino-6-tert.-butyl-1,2,4-triazin-5-one, 2-chloro-4-
ethylamino-6-isopropylamino-1,3,5-triazine, 2,3-dihydro-
2,2-dimethyl-7-benzofuranyl methylcarbamate,
3,5-di-
methyl~-methylthiophenyl N-methylcarbamate, ,-dîethyl
0-(3-chloro-4-methyl-7-coumarinyl) thiophosphate,
6,7,8,9~10,10-hexachloro-1,5,5A,6,9,9A-hexahydro-6,9-
methane-2,3,4-benzodioxathiepine-3-oxide, 1,4,5,6,7,8,8-
30 heptachloro-4,7-endomethylene-3A,4,7,7A-tetrahydro-
indene, 2-(2-furyl)-benzimidazole, 5-amino-1-bis- .
(dimethylamido)-phosphoryl-3-phenyl-1,2,4-triazole,
4-hydroxy~3-(1,2,3,4-tetrahydro-1-naphthyl)-coumarin,
S-[1,2-bis-(ethoxycarbonyl)-ethyl] 0,0-dimethyl dithio-
35 phosphate, 0,0-dimethyl 0-(4-methylmercapto-3-methyl-
phenyl) thionophosphate, 0-ethyl-0-(2-isopropoxycarbonyl-
Le A 21 930
lZ~9362
-- 7 --
phenyl)-N-isopropylthionophosphoricacidester-amide~
1-(4-chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazol-1-yl)-
2-butanone, (S)~-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-
dibromovinyl)-2,2-dimethylcyclopropanecarboxylate,
~-cyano-3-phenoxy-4-fluorobenzyl 2,2-dimethyl-3-(~
dichlorovinyl)-cyclopropanecarboxylate, pentafluorophenyl-
methyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-
carboxylate, 2,2,2-trichloro~1-(3,4-dichlorophenyl)-
ethyl acetate, 3-(phenoxyphenyl)-methyl (+-)-cis,trans-
10 2,2-dimethyl-3-(2-methyl-1-propenyl3-cyclopropanecar-
boxylate, ~-(4-chlorophenoxy)-x-(1,1-dimethylethyl)-1H-
1,2,4-triazole-1-ethanol and (2,3,4,5-tetrahydrophthal-
imi~o)-methyl chrysanthemate.
Active compounds for combating pests in the
domestic and hygiene sectors are to be understood, in
the present case, as meaning any customary active com-
pounds, of low solubility in water, which are suitable
for this purpose~ The following may be mentioned as
individual examples of active compounds of this type:
2-isopropoxyphenyl N-methylcarbamate, 0,0-dimethyl 0-
~4-nitrophenyl) thionophosphate, 0,0-dimethyl 0-(4-nitro-
phenyl) thionophosphate~ S-[1,2-bis-(ethoxycarbonyl)-
ethyl] 0,0-dimethyl dithiophosphate, 0,0-diethyl 0-(3-
methyl-4-nitrophenyl) thionophosphate, 0,0-dimethyl 0-
(4-methylmercapto-3-methylphenyl) thionophosphate and
~yclohex-1-ene-1,2-dicarboximidomethyl) 2,2-dimethyl-3-
(2-methylpropenyl)-cyclopropanecarboxylate.
Pharmacologically active compounds are to be
understood, in the present case, as meaning substances
of low solubility in water which can be employed prefer-
entially in the sec-tor of veterinary medicine. The
following may be mentioned as an example of active com-
pounds of this type: ~-cyano~3-phenoxy-4-fluorobenzyl
2,2-dimethyl-3-[~-(p-chlorophenyl)-~-chlorovinyl]-cyclo-
propanecarboxylate.
The alkylaryl polyglycol ethers present asLe A 21 930
~936;~
-- 8 --
emulsifiers in the homogeneous aqueous formulations
according to the invention are defined in a general
manner by the formula (I). In thi S formula R1 prefer-
ably represents hydrogen or straight-chain or branched
alkyl having 1 to 12 carbon atoms. R represents hydro-
gen or methyl and m preferably represents 2 or 3. The
index n preferably represents numbers from 12 to 40.
The numbers for n represent average values.
The following may be mentioned as individual
examples of alkylaryl polyglycol ethers of the formula 0:
E~x~.el~yl-(4-methylbenzyl)~-phenyl polyglycol
ether having an average of 27 oxyethylene units per
molecule.
Bis-~-methyl-(4-n-dodecylbenzyl)]-phenyl poly-
glycol ether having an average of 27 oxyethylene unitsper molecule.
Bis-(4-methylbenzyl)-phenyl polyglycol ether
having an average of 27 oxyethylene units per molecule.
Bis-(4-n-dodecylbenzyl)-phenyl polyglycol ether
having an average of 27 oxyethylene units per molecule.
Tris-[~-methyl-~4-methylbenzyl) 3 -phenyl poly-
glycol ether having an average of 17 oxyethylene units
per molecule.
The emulsifiers of this type which are used in
practice are generally mixtures of several compounds of
the formula (I). In particular, they are mixtures of
substances of the formula (I) which differ from one
another in the degree of substitution on the phenyl ring
attached to the oxyethylene unit and in the number of
oxyethylene units. This makes it possible also to cal-
culate fractional numbers as average values of the
index m. Substances for which the following average
compositions result may be mentioned as examples:
(CH3 ~ -CH )~ 7 ~ -o(c2~4o)27
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~9;~iZ
(C~3~ 2 7 ~ O~C2~0)17~
The alkylaryl polyglycol ethers o the formula (I)
are known.
The alkylarylsulphonic acid salts which are pres-
5 ent, if appropriate, in the homogeneous aqueous formul-
ations according to the invention are defined in a general
manner by the formula (II). In this formula R3 preferably
represents straight-chain or branched alkyl having 9 to
30 carbon atoms. MeQ preferably represents a sodium
10 cation or a cation of the formula
R' N
RIV
wherein
R', R", R"' and RIV independently of one another
preferably represent hydrogen, alkyl having 1 or
2 carbon atoms or hydroxyalkyl having 1 or 2
carbon atoms.
The following may be mentioned as indlvidual
examples of alkylarylsulphonic acid salts of the ~ormula
(II): sodium 4-(n-nonyl)- phenylsulphonate, sodium 4-
20 (tetrapropylene J -phenylsulphonate, ammonium 4-(i-dodecyl)-
phenylsulphonate and 2-hydroxyethylammonium 4-(n-dodecyl)-
phenylsulphonate~
The alkylarylsulphonic acid salts of the formula
(II) are known. They are employed in an undiluted form,
25 without additional solvent, in the preparation of the
formulations according to the invention.
The organic solvent present in the formulations
according to the invention is cyclohexanone.
Suitable additives which can be present in the
30 formulations according to the invention are dispersing
Le A 21 930
362
- 10 -
agents, crystallisation inhibitors, dyestuffs, cold
stabilisers, synergists, non-polar organic solvents and
also acids and bases.
Examples of dispersing agents which can be
employed are phospha-ted alkylphenols, such as phosphated
nonylphenol. Examples of crystallisation inhibitors
are alkylphenols which have been subjected to a conden-
sation reaction with l to 8 mols of ethylene oxide per mol.
Nonylphenol which has been subjected to a condensation
reaction with 2 mols of ethylene oxide per mol may be
mentioned specially in this connection. In addition,
magnesium salts are also suitable as crystallisation
inhibitors. Azo dyestuffs and phthalocyanine dyestuffs
may be mentioned as examples of dyestuffs. Urea, sugar
and sodium oleate may be mentioned as examples of cold
stabilisers. 3,4-Methylenedioxy-6 propylbenzyl-n-butyl
diethylene glycol ether (piperonyl butoxide) may be
mentioned as an example of a synergist.
Non-polar organic solvents whlch can be present
as additives in the formulations according to the inven-
tion are preferably xylene, toluene and dimethylnaph-
thalenes.
E}~amples of acids and bases which can be present
as additives in the formulations according to the inven-
tion are strong inorganic or organic acids, such asphosphoric acid, citric acid and n~dodecylbenzene-
sulphonic acid, and also inorganic bases, such as sodium
hydroxide and potassium hydroxide.
The percentage proportions of the components
present in the homogeneous aqueous formulations accord-
ing to the invention can be varied within specific
ranges. The proportion of active compound or active
compounds is generally between 0 01 and 50 % by weight,
preferably between 0.1 and 30 % by weight. The propor-
tion of alkylaryl polyglycol ether of the formula (I),if appropriate mixed with alkylarylsulphonic acid salts
Le A 21 ~30
~2~9362
of the formula (II), is generally 0.1 to 25 % by weight,
preferably 1 to 15 % by weight. The cyclohexanone is
generally present in amounts from 0.1 to 30 % by weight7
preferably from 0.5 to 25 % by weight. Additives can
5 be present in proportions of 0.05 to 15 % by weight,
preferably 0.1 to 10 % by weight. The percentage pro-
portion of water in the homogeneous aqueous formulations
according to the invention is calculated in each case
as the difference between 100 % by weight and the total
10 of the percentage proportions of the rem~i ni ng compon-
ents.
rne ratio of active compound(s), on the one hand,
to alkylaryl polyglycol ether, if appropriate mixed with
alkylarylsulphonic acid salts, on the other hand, can be
15 varied within a specific range in the formulations
according to the invention. In general, there are 1 to
10 parts, preferably 1.5 to 9 parts, of emulsifier or
mixture of emulsifiers to 1 part of active compound.
In the preparation of the homogeneous aqueous
20 formulations according to the invention it is preferable
to use all the components which have already been men-
tioned preferentially in connection with the description
of the formulations according to the invention.
If an active compound which is in the liquid
25 state at temperatures up to 40C is used in the process
according to the invention, this active compound is
generally employed in an undiluted form.
If, on the other hand, an active compound which
is in the solid state at temperatures up to 40C is
30 used in the process according to the invention, this
active compound can be employed in an undiluted form or
after previously being dissolved in cyclohexanone and/or
the emulsifier.
The reac-tion temperatures in the process accord-
35 ing to the invention can be varied within a fairly widerange. In general, the reaction is carried out at
Le A 21 930
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- 12 -
temperatures between 10C and 100C, preferably between
20C and 80C.
In carrying out the process according to the
invention, the procedure generally followed is initially
to take one or more active compounds as a mixture with cyc-
lohexanone, then to add water and also, if appropriate,
additives, while stirring with customary stirring equip-
ment, and then to add, while stirring, precisely suffi-
cient emulsifier or emulsifier mixture for a homogeneous,
clear liquid to be formed (=quasi-titration), and, if
appropriate,thentoadjust the pH value of the formulation
to a value between 2 and 10, preferably between 3.5 and
9, by adding aqueous acid or base~ In principle, the
components can be combined with one another in any
desired sequence. This latter procedure is particularly
possible if the ratio in which the components must be
prese~t in the formulatiOn for a clear homogeneousliquid to be
formed has been ascertained by means o a prelimin~ry test,
It has proved advantageous in many cases to subject the
freshly prepared formulations to a heat treatment, that
is to say to bring them to an elevated temperature for
a short time. The pH value of the formulations must in
each case be adjusted to suit the active compounds
present.
The formulations according to the invention are
completely transparent, water-clear liquids.
They can be applied either in the prepared form
or after prior dilution. The quantity applied depends
on the conce~tration of the active compounds in the
formulation and on the indication in a particular case.
The use of the formulations according to the
invention is effected, if appropriate after prior dilu-
tion, by the customary methods, that is to say, for
example, by spraying, sprink1ing or pouring.
The preparation of the formulations according
to the invention can be seen from the following examples.
Le ~ 21 930
'12~362
Preparation examples
Example 1
12 parts by weight of cyclohexanone and 81.~ parts
by weight of water are added successively to 1 part by
weight of 2-isopropoxyphenyl N-methylcarbamate. 5.5 parts
by weight of an emulsifier mixture consisting of equal
parts of the components which can be described, in terms
of formulae, as follows:
(CH3 ~ ~H ) ~ -o~ o) I (I-1)
and
n-C12~5 ~ S03 /H3~(CH2-C~-OH) ~ (II-1)
are added to this mixture at room temperature, while
stirring. When the addition is complete, stirring is
continued for a further 10 minutes and the pH is adjusted
to a value of 3.0 by means of aqueous citric acid solu-
tion. The mixture is then heated at 65~ for 10 minutes.
A completely transparent, water-clear formulation of
low ~TisCosity is formed, which, even after storage for
several weeks at temperatures above 50C, exhibits no
physical or chemical changes.
Example 2
1 part by weight of 2-isopropoxyphenyl N-methyl-
carbamate, 0 2 part by weight of (cyclohex-1-ene-1,2-
dicarboximidomethyl) 2,2-dimethyl-3-(2-methylpropenyl)-
cyclopropanecarboxylate and 1 part by weight of 3,4-
methylenedioxy~6-propylbenzyl -n-butyl diethylene glycol
ether are dissol~ed in 10 parts by weight of cyclohexan-
one, and 80.8 parts by weight of water are added
7 parts by weight of an emulsifier mixture consisting
of equal parts of the alkylaryl polyglycol ether of the
Le A 21 q30
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- 14 -
formula (I 1) and 2-hydroxyethylammonium 4-n-dodecylphenyl-
sulphonate of the formula (II-1) are added -to this mix-
ture at room ternperature, while stirring. The pH is then
adjusted to a value of 3 5 by adding aqueous citric acid
5 solution
When the addition is complete, stirring is con-
tinued for a further 10 minutes. A completely trans-
parent, water-clear formulation of low viscosity is
formed, which, even after storage for several weeks at
10 te~lperatures above 50C, exhibits no physical or chemical
changes
Example 3
1 part by weight of 2-isopropoxyphenyl N-methyl-
carbamate is dissolved in 13 parts by weight of cyclo-
15 hexanone, and 0.025 part by weight of pentafluorophenyl-
methyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-
carboxylate and 80.475 parts by weight of water are added
successively. 5.5 parts by weight of an emulsifier
mixture consisting of equal parts of the alkylaryl poly-
20 glycol ether of the formula (I-1) and 2-hydroxyethyl-
ammonium 4-n-dodecylphenylsulphonate of the formula (II-1)
are added to this mixture at room temperature, while
stirring. The pH is then adju~ted to a value of 4.5
by adding a~ueous citric acid solution.
When the addition is complete, stirring is con-
tinued for a further 10 minutes. me mixture is then
heated at 55C for 5 minutes. A completely transparent,
water-clear formulation of low viscosity is ~ormed, which,
even after storage for several weeks at temperatures
30 above 50C, exhibits no physical or chemical changes.
Exam~le 4
1 part by weight of 2,2,2-trichloro-1-(3,4-di-
chlorophenyl)-ethyl acetate is dissolved in 13 parts by
weight of cyclohexanone, and 0 2 part by weight of cyclo-
35 hex-1-ene-1,2-dicarboximidomethyl 2,2-dimethyl-3-(2-
methylpropenyl)-cyclopropanecarboxylate, 1 part by
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- 15 -
weight of 3,4-methylenedioxy-6-propylbenzyl-n-butyl
diethylene glycol ether and 76.1 parts by weight of
water are added successively. 8.7 parts by weight of
an emulsifier mixture consisting of equal parts of the
alkylaryl polyglycol ether of the formula (I-1) and
2~hydroxyethylammonium 4-n-dodecylphenylsulphonate of
the formula (II-1) are added to this mixture at room
temperature, while stirring.
Wh.en the addition is complete, stirring is con-
tinued for a further 10 minutes. A completely trans-
parent, water-clear formula-tion of low vlscosity is
formed, which9 even after storage for several weeks at
temperatures above 50C, exhibits no physical or chemical
changes.
Example 5
5 parts by weight of ~-(4-chlorophenoxy) ~~(1,1-
dimethylethyl)-1H-1,2,4-triazole-1-ethanol are dissolved
in 25 parts by weight of cyclohexanone, and 9.5 parts
by weight of nonylphenol which has been subjected to a
condensation reaction with 2 mols of ethylene oxide per
mol, and 51.9 parts by weight of water are added succes-
sively. 8.6 parts by weight of an emulsifier mixture
consisting of equal parts of the alkylaryl polyglycol
ether of the formula (I-1) and 2-hydroxyethylammonium
4-n-dodecylphenylsulphonate of the formula (II-1) are
added to this mixture at room temperature, while stirring.
When the addition is complete,-stirring is con-
tinued for a further 10 minutes. A completely trans-
parent, water-clear formulation of low viscosity is
formed9 which, even after storage for several weeks at
temperatures above 50C, exhibits no physical or chemical
changes.
Le A 21 930
