Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to herbicidal composi~
tions in the fcrm of emulsifiable conc~trates containing
3-(3,4-dichlorophenyl) 1-methyl-~-~c-:tho~y-urea (common
name: linuron) as active substance, organic solvents, emul-
sifiers and compounds inhibiting the crystallization ofactive matter in the aqueous emulsions of the concentrates.
It is known from German patent 1,028,986 to use linuron
as herbicidal agent. In most cases this active substance
is applied in the form of suspensions in water which are
obtainable by stirring a wettable powder of linuron with
water. However, prior to preparing the spray lia.uors in
the form of aqueous suspensions, the wettable powders have
to be weighed out very exactly by the applicant. When per-
formed in the open field, weighing is expensive and often
inexactly, especially in the case of wind, as the powder
is dusty and may hence may readily blown away. The appli-
cant, too, is exposed directly to this dust. The prepa-
ration of wettable powders of linuron, too, is expensive,
since the low melting point of the active matter of from
93 to 9l~C and its soft, non-brittle consistancy require
the use of expensive, fine absorptive carriers such as
synthetic silicic acid in order to prevent a sintering of
the product to be ground during milling in high-speed,
high-efficiency mills such as blowing mills or pinned disk
mills or jet mills as may be caused by the heat engaged
during the milling process. As regards the suspendibility
of linuron wettable powders in water, the international
WHO and CIPAC standards are hardly complied with, notwith-
standing the above-described great expenditure, although
the particles of the wettable powder have mean sizes rang-
ing of from 5 to 20 microns.
Hence it ~1as long been a need to apply linuron in
emulsified form via an emulsifiable concentrate. The
liquid emulsifiable concentrates are easier to handle and
far easier to measure than wettable powder formulations.
Their preparation, too, is easy. It is generally done by
dissolving the active substance in appropriate solvents
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with the addition of adequate émulsifiers. This only
requires vessels provided with a stirrer.
Linuron is distinguished by a good solubility in aro-
matic solvents as used generally for the preparation of
emulsifiable concentrates. Moreover there may be used
conventional emulsifier mixtures that are capable of form-
ing emulsifiable concentrates with linuron solutions of
the above type.
For example, British patent 982,344 describes in addi-
tion to powder formulations an emulsifiable concentratecontaining 10 weight % of linuron.
However, the known emulsifiable concentrates of linuron
have not been used hitherto in practice, since considerable
difficulties arise during the application of aqueous emul-
sions thereof. For example, emulsifiable concentrates oflinuron containing the conventional solvents or mixtures
of solvents, certainly, form emulsions on dilution with
water, however, after a short period of time, for example
after 5 to 15 minutes, and especially in cold water of
from 1Q to 15C, solid linuron precipitates from these
emulsions in the form of crystal needles of from 100 to
250 microns length.
Crystallization is accelerated when stirring the spray
emulsion. When applying aqueous spray emulsions based on
linuron of the above type, the nozzles of the spraying
equipments used for plant protection may obtstruct by the
precipitated crystal particles. A further disadvantage is
that emulsion spray liquors of the above type are less
efficient than aqueous wettable powder suspensions of
comparable concentration, as the active matter in linuron
emulsions is present in a far coarser and a far more inho-
mogeneous state of distribution owing to crystallization
phenomena than in wettable powder suspensions.
Japanese patent Sho 4510359 (patent application No Sho
42-13123) points to these disadvantages of the emulsifiable
concentrates of linuron and describes an emulsifiable for-
mulation containing great portions of cyclohexylidene-cyc-
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lohexanone as the solvent. Thus crystallization of linuron from the aqueousemulsion drops forming the deposit on the plant may be prevented when the
emulsifiable concentrate contains of from 15 to 30 weight % of cyclohexylidene-
cyclohexanone in addition to 20 weight % of linuron. However~ owing to the
high costs of the solvent described hereinbefore, a formulation of the above
type has not been used in practice. However, as is shown in Comparative
Example 4 below, cyclohexylidene-cyclohexanone, neither is capable of
preventing a crystallization of linuron from the aqueous emulsion in the spray
container.
It has now been found that liquid emulsifiable herbicidal concen-
trates that do not have the above disadvantages and that contain linuron as the
active matter, organic solvents and emulsifiers can be obtained when adding to
the concentrates as crystallization-inhibiting component, preventing a crystal-
lization of active matter in the aqueous emulsions of the concentrates, of
from 0.2 to 5 weight %, preferably from 1 to 2 weight %, of phthalic acid
dialkyl ester and/or phthalic acid alkyd resins and/or oil-modified phthalic
acid alkyd resins and/or terpene-phenol resins.
Thus, the present invention provides liquid, emulsifiable herbicidal
composition containing 3-(3,4-dichlorophenyl)-1-methyl-1-methoxy-urea (linuron)
as the active ingredient, an organic solvent and an emulsifier, which include
as crystallization-inhibiting component preventing the crystallization of
active ingredients in the aqueous emulsion of the concentrate, from 0.2 to 5
weight % of a phthalic acid dialkyl ester in which the alkyl groups contain
from 1 to 18 carbon atoms, or a phthalic acid alkyd resin, oil-modified
phthalic acid alkyd resin or terpene-phenol resin, soluble in organic solvent,
or a mixture of these compounds. The crystallization-inhibiting component
preferably comprises from 1 to 2 weight % of the composition.
Subject of the present invention are especially emulsifiable
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herbicidal concentrates containing linuron as the active ingredient organic
solvents and emulsifiers characterized in that they contain
of from 10 to 25 weight % of linuron,
of from 84.8 to 60 weight % of organic solvents, preferably
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of from 24.8 to 40 weight % of ketones, especially
isophorone, and
of from 50 to 20 weight % of aromatic solvents,
especially xylene,
of from 5 to 10 weight % of emulsifiers and
of from 0.2 to 5 weight % of phthalic acid dialkyl
ester or phthalic acid alkyd resins or oil-
modified phthalic acid alkyd resins or terpene-
phenol resins or mixtures of these compounds.
Preferred crystallization-inhibiting compounds are
oil-modified phthalic acid alkyd resins and terpene-phenol
- resins.
Particularly preferred solvents are combinations
of isophorone and xylene.
Preferred aromatic solvents are, for example, alkyl-
benzenes, preferably xylene, or higher-boiling industrial
distillation products of aromatic compounds, for example
those based on mineral oil of a boiling point of from 156
to 312C (under normal pressure).
Preferred ketones are especially aliphatic or cyclo-
aliphatic ketones, especially liquid ketones of a flash
point above 400C (measured in a closed recipient). The
ketones are used to improve the solubility of linuron in
aromatic solvents and to improve the stability of low tem-
peratures of the emulsifiable linuron concentrates, for
example at a temperature of from about 0C to -10C. Espe-
cially appropriate ketones are, for example, isophorone
and cyclohexanone, isophorone being the most preferred
; compound.
Emulsifiable concetrates are obtained, for example,
on dissolution of the active ingredient in an organic sol-
vent or in mixtures of solvents, such as those containing
xylene and isophorone, and on addition of an emulsifier.
Appropriate emulsifiers are all the known surfactants
used as auxiliary in the formulation of emulsifiable con-
centrates and which are soluble in xylene, Por example cal-
cium salts of dodecylbenzene-sulfonic acids or calcium
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salts of chlorinated (C13 15) alkane-sulfonic acids or po-
lyglycol ethers, for example of nonylphenols or polyglycol
ethers, for example of fatty alcohols or for example, reac-
tion products of castor oil and ethylene oxide.
Appropriate phthalic acid esters are ~e~e~Rb~ phtha-
lic acid dialkyl esters whose alkyl groups each have up to
18 carbon atoms, especially up tc 12 carbon a~oms and
which may ie substituted, for example phthalic acid dime-
thyl or especially phthalic acid diisooctyl ester, as used
as plasticizers in plastic processing. In plant protec-
tion compositions, phthalic acid esters of the above type
ha~e somtimes been used as evaporation-inhibiting additives
in the formulation of phosphor~s ester as the active ingre-
dient (cf. German Offenlegungsschrift 2,738,87~; French
patent 2,092,898). However, they have not been used hlther-
to as crystallization-inhibiting agent for active su~stances
in aqueous emulsions of emulsifiable concentrates, espe-
cially of linuron.
Further appropriate crystallization-inhibiting corn-
pounds with regard to linuron in aqueous emulsions i.n addi-
tion to the simple phthalic acid dialkyl esters are espe-
cially phthalic acid ester groups-containing polyconden-
sates that arP soluDle in organic so'~ents, for example
those as known as phthalic acid alkyd resins or espccially
as oil-modifi.ed phthalic acid alkyd resins.
By oil-modified phthalic acid alkyd resins there are
to be understood polyesters soluble in organic sol~ents and
containing phthalic acid ester groups. These polyesters
are obtained by directly esterifying, for example either
phthalic acid or phthalic acid anhydride with aliphatic
fatty acids and polyalcohols, such as glycerol, sorbitol,
pentaerythritol, in a single-stage process or by trans-
esterifying fatty acid triglycerides with polyalcohols-
(alcoholysis) and subsequently esterifying the resulting
reactior. product with phthalic acid or phthalic acid anhy-
dride in a ~second process step.
The fatty acids used as such or the fatty acids ob-
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tained from the fatty oils, which are used subsequently
for esterification, may be saturated or unsat.urated.
Phthalic acid alkyd resins as well as their prepara-
tion are described, for example in "Winnacker-Kuchler,
Chemische Technologie", Volume 5, pages 410 - 422, Carl
Hanser Verlag, Munich, 1972.
Especially appropriate oil-modified phthalic acid
alkyd resins are, for example those obtained by synthesis
of, for example inter alia 40 weight % of castor oil and
37 weight g of phthalic acid anhydride (alkyd resin A) or
those obtained by synthesis of especially selected, unsa-
turated drying oils (for example cotton seed oil) in an
amount of 45 weight % and of 27 weight % of phthalic acid
anhydride (alkyd resin B), or those obtained by synthesis
~5 of inter alia 37 weight % of isononanic acid, calculated
as triglyceride and of 40 weight % of phthalic acid anhy-
dride (alkyd resin C).
The terpene-phenol resins further used in accordance
with the present invention for the crystallization-inhibit-
ing stabilization of emulsifiable concentrates of linuronsand which are soluble in organic solvents, are described,
~or example in "Winnacker-Kuchler, Chemische Technologie",
volume 3, page 506, Karl Hanser Verlag, Munich 1971. They
are obtainable by condensation of terpene-type hydrocarbons
such as~ pinene or oil of turpentine with phenols or alkyl-
phenols in the presence of catalysts, such as boron fluoride
(cf. Ullmann, Enzyklopadie der Technischen Chemie, 4th edi-
tion, (1976), vol. 12, page 543; Rompp, Chemielexikon, 7th
edition (1977), vol. 6, pa~e 3506).
Preferred resins are not-hardening, oil-soluble ter-
pene-phenol resins (terpene-phenol resin A).
The emulsifiable concentrates of linuron stabilized
by cr-ystallization-inhibiting compounds in accordance with
the present invention are distinguished by an outstanding
resistance to storage as regards their chemical and physi-
cal properties and their utilitariar. properties, which has
been demonstra'ed by storage tests under severe conditions,
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for example storage for 3 months at 50C or the cold test
at -10C.
The emulsifiable concentrates of linuron are prepared
in simple manner by adding to the solvents and dissolving
therein while stirring linuron, emulsifiers and the phtha-
lic esters, phthalic ester resins, oil-modified phthalic
ester resins, terpene-phenol resins or mixtues of said
compounds.
Surprisingly the emulsifiable concentrates of linuron
in accordance with the present invention with the same
quantities applied, are distinguished by a better herbici-
dal action as compared with linuron wettable powders, upon
emulsification of comparable formu]ations in water or upon
application in suspended form, which means an economy of
active matter in practice. For combating weeds, the herbi-
cidal concentrates in accordance with the present invention
are applied from an aqueous emulsion in efficient amounts,
for example an amount of from 0.03 to 0.13 kg of active
matter per hectar.
The following examples demonstrate the action of the
crystallization-inhibiting components in accordance with
the present invention and the biological activity of the
emulsifiable linuron concentrates in accordance with the
invention.
The emulsifiable concentrates used for the comparative
tests contained 10 or 20 weight ~, respectively, of linuron.
Corresponding results are obtained as well when adjusting
the concentration of linuron in the concentrates, for ex-
ample to 15 or 25 weight %, respectively, it being possible
to vary the solvent portions simultaneously accordingly.
The action of the crystallization-inhibiting compo-
nents on the crystallization behavior of linuron in aque-
ous emulsions of emulsifiable concentrates is examined by
testir.g the emulsions under the microscope for crystals
formed and optionally by determining the crystal size. To
this end, there are prepared emulsions each of which con-
tain 2.5 weight ~ of emulsifiable concentrate in 97.5
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weight parts of water of 342 ppm hardness (WHO svandard1
cf. CIPAC-~andbook (1970), page 878) and of a temperature
of 10C or 30C, respectively. The emulsions are stirred
at 10C or 30C, with microscopic examinations for linuron
crystals formed and optionally with determinations of the
crystal sizes being carried out after 15, 30 and 120
minutes and after a 3 hours' standing.
_ormulation Examples
COMPARATIVE EXAMPLE 1: (corresponding to British patent
982,344, Example 4)
10 weight % of linuron
70 weight % of xylene
20 weight % of emulsifier mixture from polyoxethylated
B ethers and~oil-soluble petroleum sulfona-
tes (Emcol H 140).
After a 15 minutes' stirring of the 2.5 % aqueous emul-
sion linuron crystal needles of 70 to 80 microns and after
30 minutes those of 220 to 240 microns size have formed.
COMPARATIVE EXAMPLE 2: (analogously to Japanese patent
Sho 45 10 359)
20 weight % of linuron
20 weight % of 2~cyclohexylidene-cyclohexanone
50 weight ~ of xylene
5 weight % of chlorinated calcium salt of (C13 15)
alkane-sulfonic acid
1 weight % of oleylalcohol polyglycol ether (8 AeO)
4 weight % of castor oil polyglycol ether (40 AeO)
After a 15 minutes' stirring of the 2.5 % aqueuos
emulsion linuron crystals of 90 to 140 microns and after
30 30 minutes crystals of 190 to 240 microns have formed.
COMPARATI~E _XAMPLE 3:
20 weight p of linuron
35 weight % of xylene
35 weight % of isophorene
4.5 weight % of castor oil polyglycol ether (40 AeO)
2.0 weight % of oleyl alcohol polyglycol ether (8 AeO)
3.5 weight ~ of calcium salt of dodecylbenzer,e-sulfo
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nic acid
After ~ 10 minutes' stirring of the 2.5 % aqueous emul-
sion linuron crystals of 90 to 150 microns and after 30 mi-
nutes crystals of 200 to 260 microns have formed.
COMPARATIVE EXAMPLE 4:
weight g of linuron
weight % of xylene
weight % of cyclohexanone
4.5 weight % of castor oil polyglycol ether (40 AeO)
2.0 weight % of oleyl alcohol polyglycol ether (8 AeO)
3.5 weight d of chlorinated calcium salt of (C13 15)
alkane-sulfonic acid.
- After a 10 minutes' stirring of the 2.5 % aqueous emul-
sion linuron crystals of 90 to 110 microns and after 30 mi-
r.utes crystals of 200 to 250 microns have formed.
COMPARATIVE EXAMPLE 5:
A linuron-50-wettable powder (having a conter.t of ac-
tive substance of 50 weight %) was prepared for this
bio]ogical test by grinding the following mixture twice in
a pinned disk mill at a rotational speed of the mill disk
of 150 m/sec. to a fineness below 10 microns:
50.0 weight % of linuron
30.0 weight % of finely divided synthetic silicic acid
10.0 weight % of sodium salt of dinaphthylmethane-di-
sulfonic acid
0.5 weight % of sodium salt of oleyolmethyltauride
2.0 weight % of sodium salt of dibutylnaphthalene-
sulfonic acid
7.5 weight % of diatomaceous earth.
The formulations according to the invention have the
fol]owing compositions:
E X A M P L E 1:
10 weight % of linuron
- 15 weight ~ of isophorone
63 weight % of industrial distillate of aromatic pro-
ducts b.p. 183-270C
4.5 weight % of calcium salt of dodecylben~ene-sul-
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fonic acid
4.5 weight % of castor oil polyglycol ether (40 AeO)
1.0 weight % of oley]. alcohol polyglycol ether t8 AeO)
2.0 weight ~ of alkyd resin A.
S After a 2 hours' stirri.ng of the 2.5 % aqueous emul-
sion a crystal formation was not observed, neither after a
further 3 hours' standing.
E X A M P L E 2:
_
20.0 weight % of linuron
35.0 weight % of isophorone
33.0 weight % of xylene
4.5 weight % of castor oil polyglycol ether (40 AeO)
2.0 weight % of oleyl alcohol polyglycol ether (8 AeO)
3.5 weight % of calcium salt of dodecylbenzene-sul-
fonic acid
2.0 weight % of alkyd resin A.
After a 4 hours' stirring and after a 4 hours' standing
of the 2.5 % aqueous emulsion a crystal formation could
not be observed.
E X A M P L E S 3, 4, 5, ~:
These examples are carried out as Example 2, except
that 2 weight ~ of alkyd resin C or of alkyd resin B or of
terpene-phenol resin A or 1 weight ~ of alkyd resin A + 1
weight % of terpene-phenol resin A are used instead of 2
weight % of alkyd resin A.
After a 3 hours' stirring and after a 4 hours' stand-
ing a crystal formation was not observed in the 2.5 % aque-
ous emulsions of the concentrates in all of the examples.
E X A M P L E ?
20.0 weight % of linuron
35.0 weight % of isophorone
33.0 weight % of industrial distillate of aromatic
compounds, b.p. 183 to 312C
4.5 weight ~ of castor oil polyglycol ether (40 AeO)
3.2 weight % of calcium salt of dodecylbenzene-sulfo-
nic acid
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2.3 weight ~ of oleyl alcohol polyglycol ether (8 AeO)
2.0 weight % of alkyd resin A.
After a 2 hours' stirring and after a further 3 hours'
standing a crystal formation of the 2.5 ~ aqueous emulsions
was not observed.
E X A M P L E S 8, 9:
20.0 weight % of linuron
35.0 weight % of isophorone
30.0 weight % of xylene
5.0 weight % of phthalic acid diisooctyl ester or di
methyl ester
4.0 weight % of castor oil polyglycol ether (40 AeO)
2.0 weight % of oleyl alcohol polyglycol ether (8 AeO)
4.0 weight ~ of calcium salt of chlorinated (C13 15)
alkane-sulfonic acid.
The 2.5 % aqueous eMulsions showed no crystal formation
after stirring for 1 and a half hours.
Biological Examples
E X_A M P L E 1:
Comparative Test of Linuron 20 EC with Linuron 50 Wettable
Powder (WP)
The crop plants oats (Avena), mustard (Sinapsis) and
horse beans (Vicia faba) were grown in test pots in loamy
soil and after emergence of the plants the products were
sprayed in an amount of 300 l/ha under 3 bars. The degree
of damage, expressed in percentages, was determined after
4 weeks, compared to the untreated control O
ProductDose kg/ha Damage in Percentage with
A.l. Oats Mustard ) Horse beans
Linuron 20 EC 0.03 0 87 7
~according to 0.06 0 96 10
Example 2)0.13 16 100 13
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Product Dose l~g/ha Damage in Percentage with
A.I. Oats Mustard ) Horse beans
Linuron 50 % WP 0.03 0 70 7
(according to 0.06 0 90 10
Comp. Ex. 5) 0.13 16 99 16
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) Mustard is used as test plant for dicotyledonous weeds.
A comparison of both formulations shows that the EC
formulation, which can be seen with mustard, has a higher
efficiency (87 %3 than the WP formu:lation ('70 %), with
comparable quantities applied of active matter. With the
orop plants oats (for cereals) and horse beans (for
leguminosae) the EC formulation exhibited as tolerant as
the WP formulation.
