This invention relates to novel plant pro¬ tective microemulsion compositions, more particular- ly to solutions containing pyrethroids as active ingredients as well as to stable aqueous microemulsions prepared therefrom. The invention further relates to the preparation and use of these solutions and microemulsions . The aqueous microemulsions according to the invention can be transformed to other compositions such as aerosols by using suitable auxiliary materials.

It is known that synthetic pyrethroids are used to a continuously increasing extent in the up- -to-date plant protection since a satisfactory protec¬ tion can be achieved by applying the active ingredient in amounts as low as 10 to 100 g/ha and on the other hand, the residue of the active ingredient becomes negligible within a relatively short time of decomposi- tion. The pyrethroid-type active ingredients are used in the form of wettable powders ( P), suspension concentrates (FW) and most frequently as microemulsion compositions (EC). General demands made on the up- -to-date emulsion concentrates comprise a) ensuring the very dilute emulsion phase state in the concentration for application by an econo¬ mical amount /75 to 150 g/litre (abbreviated:

b) avoiding the use of xylene as solvent because of problems connected with the safety, environ¬ mental protection and phytotoxicity.

The low amount of the surface active agent can be ensured by a suitable selection of up-to-date surface active substances. For replacing xylene, the solvent manufacturers developed specific but expensive novel types of solvents whereas the formulating manu- facturers made efforts to replace the solvents by aqueous systems. Thus, in the German patent specifica¬ tion NO. 3,235,612, aqueous microemulsions are described which contain: 0.1 to 80 % by weight of active ingre¬ dient together with 1 to 20 % by weight of a particular emulsifier mixture and optionally 1 to 30 % by mass of organic solvent, being partly miscible with water; as well as water. The particular emulsifier is a mixture of an alkylaryl polyglycol ether with an alkylaryl- sulfoπate salt. The emulsion stability of the emulsion concentrates reported in the German patent specifica¬ tion No. 3,508,643 is ensured by polyviπyl alcohol and an organic acid. The aqueous microemulsions described in the German patent specification No. 3,624,910 contain as emulsifiers a phenol or a phenolate salt substituted by ethoxylated and phosphorylated styryl group in combination with one or more non-phosphorylated emul¬ sifying agent(s) together with 5 to 30 % by mass of

an usual solvent.

The aqueous microemulsions set forth in the published European patent application No. 0,160,182 contain pyrethroids and phosphoric acid esters as active ingredients and ethoxylated tristyrylpheπol , ethoxylated distyrylphenol-ammonium sulfate and an alkylarylsulfonate as emulsifying agents. Emulsion concentrates containing low molecular aliphatic alcohols and ketαπes as stabilizing agents are described in the published Japanese patent application No. 51-59778. Another problem of the EC-type compositions emerges therein that a stable spray liquid, required to remain stable in the most cases for at least 24 hours, has to be prepared from the given emulsion concentrates 'by using waters with various hardnesses. In addition, synthetic pyrethroids are weakly soluble in aliphatic hydrocarbons and apolar solvents which in turn are preferred from the viewpoint of phytotoxi- city, environmental protection and safety; thus, they can meet the criterion of the cold-resistance only with difficulties.

The aim of the invention is to prepare an emulsion solution (pre-formulation) with a composition meeting the demands made on the up-to-date emulsion concentrates such as the low surface active agent content, absence of aromatic solvents and the possibi¬ lity of preparing a stable aqueous microemulsion even

under the extreme use conditions.

Thus, the present invention relates to a novel solution of a plant protective agent, 1 litre of which contains - 1 to 150 g/1 of one or more synthetic pyrethroid(s) as active ingredient(s) and

- 40 to 70 g/1 of ethoxylated (E0= 10 to 14)-propoxylated (P0 = 18 to 22) πoπylphenol,

- 10 to 20 g/1 of linear calcium dodecylbenzenesulfonate, - 90 to 120 g/1 of polyoxyethyleπe(20)-sorbitan moπo- laurate as surface active agents, and a solvent mixture (A) consisting of

- 9 to 11 % by volume of hydrogenated aliphatic hydro¬ carbon containing 45 % of naphthene, - 18 to 30 % by volume of propylene glycol,

- 28 to 35 % by volume of pine fatty acid,

- 23 to 30 % by volume of sunflower oil,

- 5 to 10 % by volume of an 1:1 by volume mixture of methanol or ethanol, respectively with isobutanol in an amount supplementing up to 1 litre.

One litre of the solution of the plant protec¬ tive agent according to the invention can be prepared by dissolving

- 1 to 150 g/1 of synthetic pyrethroid, - 40 to 70 g/1 of ethoxylated (E0 = 10 to 14)-propoxy- lated (PO = 18 to 22) πonylphenol,

- 10 to 20 g/1 of linear calcium dodecylbenzeπesul- foπate ,

- 90 to 120 g/1 of polyoxyεthyleπe(20)-sorbitaπ mono- laurate in 500 ml of a solvent mixture (A) consisting of

- 9 to 11 k by volume of a hydrogeπated aliphatic hydro¬ carbon containing 45 of naphthene,

- 18 to 30 % by volume of propylene glycol,

- 28 to 35 % by volume of pine fatty acid, - 23 to 30 % by volume of sunflower oil,

- 5 to 10 % by volume of an 1:1 by volume mixture of methanol or ethanol, transmission with isobuta¬ nol and supplementing the solution thus obtained up to 1 litre with the solvent mixture (A).

The invention further relates to a transparent emulsion of a plant protective agent having an average drop size below 100 /urn; a relative interfacial tension below 3 mN/m; and a light transmission above 95 % in 0.01 % concentration, above 90 in 0.1 % concentration and above 35 % in 1 % concentration through a layer thickness of 10 mm after an examination period of 120 minutes, which comprises 0.01 to 1.0 % by volume of the above

solution and water of a hardness of 0 to 500 ppm in an amount necessary to fill up to 100 % by volume.

As synthetic pyrethroids the tetramethrin /chemically 3 ,4,5,6-tetrahydrophthalimidomethyl (1RS)- -cis-traπs-chrysaπthemate7 and/or deltamethrin /chemical¬ ly (S)-^ -cyano-3-phenoxybeπzyl (lR)-cis-3-(2,2-di- bromvinyl)-2,2-di ethylcyclopropanecarboxylate7 and/or feπpropathrin /chemically (RS)- > -cyano-3-pheπoxybenzyl 2,2,3,3-tetramethylcyclopropane carboxylate7 and/or fenvalerate /chemically (RS)-c*.-cyaπo-3-pheπoxybeπzyl (RS)-2-(4-chlorophenyl)-3-methylbutylate7 and/or flucitriπate /chemically (RS)- _* -cyano-3-pheπoxybenzyl (RS)-2-(4-difluoromethoxyphenyl)-3-methylbutyrate7 and/or permethriπ /chemically 3-phenoxybenzyl 3-(2,2- -dichlorovinyl)-2,2-dimethylcyclopropane carboxylate/ and/or cypermethrin /chemically (RS)-p<^-cyaπo-3-pheπoxy- beπzyl (IRS)-cis-trans-3-(2,2-dichlorovinyl)-2,2-di- methylcyclopropaπe carboxylate7 and/or the eπaπtiomeric pairs of (RS)-<?.-cyaπo-3-phenoxybenzyl (lRS)-cis-traπs- -3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropaπe carb¬ oxylate

(lR)-cis-(S)+(lS)-cis-(R) and (lR)-traπs-(S)+(lS)- -trans-(R) or the mixtures thereof may be contained in the plant protective compositions according to the invention.

The stability of the diluted compositions according to the invention was studied between the concentration limits of 0.01 to 1 % in the presence

of salts resulting in a water hardness of 34.2 to 342 ppm by using the standardized CIPAC method. Samples were taken from the emulsions after 0, 30 and 120 minutes, then after 24 hours and the drop size dis- tributioπ (Zetasizer lie) in the samples and their light transmittance at 845 ,um wavelength in a 10 mm glass cuvet was examined.

The interfacial tension of the composition as related to water (CIPAC A and D) was determined by using the hanging drop method.

The composition, physico-chemical characte¬ ristics and effects of the compositions according to the invention are illustrated in detail by the following non-limiting Examples.

Example 1

The preparations according to the compositions 1 to 16 were prepared uniformly by using the following method. 1000 ml of the solution were weighed together from the solvent mixture according to the volume ratio. 500 ml of the solution obtained were weighed into a graduated cylinder of 1000 ml volume and the synthetic pyrethroids and emulsifiers were dissolved therein. After complete dissolution, the solution was filled up to 1000 ml with the above solvent. The compositions of the preparations according to the Examples are

summarized in Tables 1 and 2. The characteristics of the compositions are shown in Table 3.

The following abbreviations are used in the Tables:

Components Abbreviation in the Tables

Ethoxylated(E0=13)-propoxylated(P0=21) nonylpheπol EPN

Linear calcium dodecylbenzenesulfonate LDBC

Polyethoxylene(20)-sorbitaπ moπooleate PSMO

Propylene glycol PGL

Pine fatty acid PFA Sunflower oil SO

1:1 by volume mixture of methanol or MB or EB, ethanol, respectively, with isobutanol respectively Hydrogenated aliphatic hydrocarbon mixture containing 45 % of naphthene HAM

Table 1

Compositions

Components 1 2

Cypermethrin (g/1) 150 75

(lR)-cis-(S)+(lS)-cis-(R) (g/1)

( 1R)-trans-(S)+(IS)-trans-(R) (g/1)

EPN (g/1)

LDDC (g/1)

P5M0 (g/1)

completed to 1000 ml with:

PGL ( h by vol.) 20.6 19.1 19.1 19.1 23.0 23.0 23.0 23.0

TZS (% by vol.) 28.6 33.3 33.3 33.3 31.0 20.6 31.0 31.0

HOL (% by vol.) 23.0 20.6 20.6 23.0 26.2 20.6 26.2 26.2

E0 (% by vol.) 9.5 9.6 9.5 9.5 9.5 9.5 9.5 9.5

HAM (% by vol.) 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5

Table 2

Compositions

Components 9 10 11 12 13 Deltamethrin (g/1) 25 Fenpropathrin (g/1) 100 Fenvalerate (g/1) 110 Permethrin (g/1) 250

EPN (g/1) LDDC (g/1) PSMO (g/1)

supplemented to 1000 ml with:

PGL (% by vol.

TZS (% by vol.

N0L (% by vol.

MB (% by vol.

EB (% by vol.

HAM (% by vol.

Table 2

(contd. )

Components

(lR)-trans-(S)+(lS)-trans-(R)

Tetra ethrin

Piperonylbutoxide

EPN (g/1)

LOBC (g/1)

PSMO (g/1)

supplemented to 1000 ml with

PGL (% by vol.)

TLS (% by vol.)

H0L (% by vol.)

EB (% by vol.)

HAM (% by vol.)

Table 3

Physico-chemical characteristics

Example No.

Dilution ( H ) light transmission^

0 h

0.5 h

2 h

24 h

Surface tension (mN/m)

Average drop size (n )

Table 3

(contd. )

Example No.

Dilution (H) light transmission's

0 h

0.5 h

2 h

24 h

Surface tension (mN/m)

Average drop size (nm)

Table 3

(contd. )

Example No.

Dilution (%) light transmission^

0 h

0.5 h

2 h

24 h

Surface tension (mN/m)

Average drop size (nm)

Table 3

(contd. )

Example No.

Dilution (%) light transmission^

0 h

0.5 h

2 h

24 h

Surface tension (mN/m)

Average drop size (n )

Table 3

(contd. )

Example No.

Dilution (%) light transmission^

0 h

0.5 h

2 h

24 h

Surface tension (mN/m)

Average drop size (n )

Table 3

(contd. )

Example No.

Dilution (%) light transmission^

0 h

0.5

2 h

24 h

Surface tension (mN/m)

Average drop size (nm)

Exampl e 17

Emulsions with a 1000-fold dilution were prepared from the samples according to the above for¬ mulation Examples by using CIPAC D water, then the activity of the emulsions was determined in a fresh state and after standing for 5 hours.

The samples taken from the upper third of the emulsions were further diluted with CIPAC D water in the given moments to obtain emulsions with con- ceπtrations of 2.5, 1.25, 0.625, 0.3125, 0.15625 and 0.078125 ppm, calculated on the active ingredient. Two ml of these emulsions were sprayed into Petri plates of 9 cm diameter by using a Potter's tower.

After complete drying, 20 3 days old female houseflies (Musca domestica WHO/SRS with a body weight of 21 _+ 1-5 mg each) mildly narcotized by carbon dioxide were put into the Petri dishes and after 24 hours the number of the dead flies were determined. This examination was carried out for each concentra- tion in 3 parallels.

From the data obtained the equipotential concentrations L cn values) expressing the activity were calculated by probit analysis. The lower C,- _n values mean higher activities. The results are summarized in Table 4.

Table 4

Samples Duration of the activity LC '5 _ς 0 _n -+_ examination after preparation of the emulsion (hour)

CNX 5 EC Example, control 0

CHX 5 ME Example 7, product 0

CHX 5 EC Example, control 5

Composition of CHX 5 EC:

(lR)-cis-(S)+(lS)-cis-(R) (g/1) 20

(lR)-trans-(S)+(lS)-trans-(R) (g/1) 30

Emulsifiers (g/1) 100

Xylene completed to 1000 ml

Examples 18 to 27

The aerosols shown in Table 5 are prepared from the aqueous microemulsions according to the in¬ vention in a manner known per se.

Table 5

Example No. 18 19 20 21 22 23 24 25 26 27

Composition of Example 4 in an aqueous dilution of 1 % (% by vol.) 40 40 Composition of Example 7 in an aqueous dilution of 1 % (% by vol.) 40 40 Composition of Example 14 in an aquoue dilution of 1 % (% by vol.) 40 40 Composition of Example 15 in an aqueous dilution of 1 % (% by vol.) 40 40 Composition of Example 16 in an aqueous dilution of 1 % ( by vol.) Ethanol (% by vol.) Liquid propane-butane (% by vol.) Isopropaπol ( h by vol.)