PLANT-PROTECTIVE COMPOSITION

Abstract: The invention relates to an emulsifiable microemulsion concentrate containing a phosphoric acid ester and/or thiophosphoric acid ester as active ingredient. In addition to 20 to 80 % by weight of active ingredient, the composition comprises: 5 to 70 % by weight of a nonionic surface active agent, preferably a block copolymer with a molecular weight of 1000 to 10000 formed from polyethylene oxide and polypropylene oxide, an alkylphenol polyglycol ether, ethoxylated fatty alcohol or a mixture of nonionic surface active agents; 2 to 50 % by weight of water; if desired, 1 to 50 % by weight of a co-surfactant, preferably C1-8 straight or branched chain and/or cyclic alcohol, C3-8 straight or branched chain and/or cyclic ketone, esters of C1-6 fatty acids with C1-6 alcohols or the mixture thereof; and if desired, 15 to 30 % by weight of a water-immiscible organic solvent.

Description: PLANT-PROTECTIVE COMPOSITION The invention relates to an emulsifiable ic- roe ulsion concentrate containing an ester of phosphoric or thiophosphoric acid or their mixture as active in¬ gredient. The preparation of plant-protective agents sets two kinds of problems: 1) the preparation of an active ingredient possessing the desired biological activity; and 2) the formulation of the active ingredient to a composition providing an easy handling for the user. Among the usual formulations of plant-protecti agents, the wettable powders (WP-s) and emulsifiable concentrates (EC-s) are most important and represent nearly 90 of the plant-protective agents available commercially at present. Being liquids, the EC composi¬ tions are easier to handle, their portioning can be solved by a simple volumetric measurement and, from the viewpoint of the labour-safety it is advantageous that at mixing the appeareπce of the health-damaging materials in the air has not to be considered (which is practically inevitable in the course of e.g. filling powders from bags to mixing tanks). In addition, the biological activity of the EC compositions is higher than that of the WP compositions. On the basis of the obvious advantages of EC compositions, it could be expected that these formulations would play a predomi¬ nant role on the market. Actually however, the number of WP compositions is somewhat higher than that of the EC-s. The reason for this is that an EC composition can be prepared only from an active ingredient which is liquid or, when a solvent can be found in which the active ingredient can be dissolved to give a solu¬ tion of 10 to 85 % concentration (depending on the usual concentrations of the application) without any risk of. the interim alteration of the active ingredient. An other drawback of the EC compositions arises from their high solvent content whereby they are inflammable and explosive and the environment is polluted. The drawback of the EC compositions can be diminished by formulating the active ingredient to an emulsifiable microemulsioπ concentrate. Microemulsioπ is a colloidal system which, in a first approach differs from a true emulsion in the dimension of its particles which are smaller by an order of magnitude than those of a true emulsion. According to the general definition, this system con¬ tains surface active agents and two immiscible liquids, one of them is usually water, though, in principle, it is also possible to prepare water-free microemulsioπ by using an other solvent. The surfactant may be the mixture of even 6 to 8 tensides and additionally, it may contain alcohols or amines of medium chain length as auxiliary surfac¬ tants (co-surfactants). A peculiarity of this complicate system lies in its thermodyπa ical stability: it is formed spontaneously from the appropriate components without the input of an outer energy. The direct reason for this formation is that the interfacial tension between the two phases is very small, it approaches zero and transiently it even becomes negative. In the outer appearance, a microemulsion is a transparent solution as a consequence of the very small size of the disperse particles. The size of the moπodisperse spheres varies between 0.01 and 0.2 /urn. Although this system is transparent, all monochromatic lights such as electron or neutron radiation or X rays a re scattered by the system whereby the determination of the particle size is also rendered possible. Being a peculiar colloidal system, a micro¬ emulsioπ may prominently be used for formulating plaπt- -protective agents on the basis of its above characte- ristics. An additional advantage of the microemulsion consists in that it contains a lower amount of organic solvent than an EC composition which is preferably from the viewpoint of both the environment protection and the danger of fire and explosion. Microemulsioπs are preferably used in the cases of ULV applications. It is characteristic of the known microemul¬ sion EC compositions that, in addition to the active ingredient they contain a combination of nonionic and anionic surface active agents as well as a high amount of a co-surfactant (capillary active substance). In DE-OS Nos. 3,236,240 and 3,235,612 as well as in US-PS No. 4,469,675 microemulsion formula¬ tions are described which contain mixture of: an alkyl- phenol polyglycol ether with calcium dodecylbenzeπesul- foπate; alkylphenol polyglycol ether with triethanol- amine dodecylbeπzeπesulfonate; or polyoxyethylene-di- styrene phenyl ether with calcium dodecylbenzenesulfonate and pαlyethyleneσxyde sorbitol monostearate as combina¬ tions of nonionic and anionic surface active agents. Further on, each formulation contains a co-surfactant; most of the examples relate to cyclohexanoπe. The co po- sitions reported in the above-cited United States patent specification always contain polyvinylalcohol, too. Since the esters of thiophαsphoric acid are decomposed even in weakly alkaline media, the anionic surface active agents commonly used for microemulsion compositions cannot be considered for the formulation thereof. In US-PS No. 4,304,587 an EC composition is described which contains an organic phosphoric acid ester dissolved in a mineral oil, in petroleum solvents, chlorinated hydrocarbons, alcohols, glycols, ethers, esters, ketones or their mixtures by using an anionic phosphate ester and an alkylphenol polyglycol ether nonionic tenside as emulsifying agent. In GB-PS No. 2,071,496 EC compositions are reported which contain organic phosphoric or thiophos- phoric acid esters as active ingredient; these composi¬ tions contain 1 to 30 % by weight of active ingredient as well as 20 to 70 % by weight of a nonionic emulsifier and 20 to 60 % by weight of a mineral oil or a softening agent. In the examples of this patent specification, noπylphenyl polyglycol ether (E0=10) is used as a non¬ ionic emulsifying agent. When this EC composition is poured onto water, a true emulsion is formed sponta¬ neously. The problems arising from the formulation of phosphoric and thiophosphoric acid esters are avoided by the solution described in GB-PS No. 2,049,425. No effort is made to prepare an EC composition, but a concentrated aqueous true emulsion is prepared which is stabilized by a polymer (polyviπyl alcohol with a polymerization degree below 1500, tragacaπtha gum, guar gum, algiπates, methyl-cellulose, polyacrylic acid and the like) dissolved in water. The drop lets of the emulsion are rather large (1 to 50 um according to the examples) however, because of the high viscosity of the aqueous medium, no sedimentation or creaming has to be considered during the storage. A drawback of this composition is that it can be stored for only six months instead of the usual two years; furthermore, owing to the high viscosity, the composition is more difficult to dissolve than are the usual EC composi¬ tions. An interesting way of formulating phosphoric and thiophosphoric acid esters is described in GB-PS No. 2,050,170, according to which the EC composition contains 10 to 99.5 % of an organic acid or a mixture of organic acids. In this composition, the primary role of the tensides, preferably anionic tensides (poly- oxyethylenated sorbitol oleate, alkylphenol polyglycol ether and the like) is to increase the wettability and not to stabilize the emulsion formed. According to HU-PS No. 169,435, nonionic (alkylar-yl polyglycol ether) and anionic (alkylbenzene- sulfonate) surface active agents are used in a total amount of 10 % together with a suitable co-surfactant (cyclohexaπone, di ethylforma ide and the like) for formulating O-phenyl-thioπo-thiolphosphoric acid esters into an EC composition. On the basis of those described above it can be stated that no microemulsion composition is known which contains an organic phosphoric or thiophos- phoric acid ester as active ingredient; furthermore, the prescriptions developed for microemulsion composi¬ tions cannot be adapted for phosphoric or thiphosphoric esters since these compositions contain basic compo¬ nents in amounts sufficient to start the chemical decom- position of the ester or to rapidly decrease the active ingredient during storage. The present invention is aimed to develop a stable microemulsion concentrate containing a phosphoric and/or thiophosphoric acid ester in a commonly used amount as active ingredient. It has been found that stable microemulsioπ composition can be prepared from organic phosphoric and thiophosphoric acid esters by using only a nonionic surface active agent. The microemulsioπ state can be adjusted in the characteristic temperature range by varying the concentration of a suitable nonionic surface active agent, optionally by using a co-sur actant (capil- lary active substance) . The microemulsion compositions according to the invention characteristically contain: 20 to 80 % by weight of an organic phosphoric or thiophosphoric acid ester derivative as active ingredient; 5 to 70 % by weight of a nonionic surface active agent (preferably alkylphenol polyglycol ether, ethoxylated fatty alcohol, a block copolymer formed from ethylene oxide and propylen oxide or their mixtures; and 2 to 50 % by weight of water. Optionally, the compositions may contain 1 to 50 % by weight of a co-surfactant (capillary active substance) as well as other usual additives (agents diminishing the evaporation or improving the spreading or strengthening the adhesion). The co-surfactants preferably used in the compositions according to the invention are C-, , straight and/or branched chain alco¬ hols, C , n cyclic alcohols, C- * □ straight and/or branched chain and/or cyclic ketones, esters of C, , fatty acids with C, , alcohols and their mixtures. Optionally, the compositions may contain 15 to 30 % by weight of a water-immiscible organic solvent, preferably xylene. If desired, the compositions according to the invention may contain 1 to 40 % by weight of an agent enhancing the efficiency such as piperonyl-butoxide The systems according to the invention were qualified as microemulsiαπs when their extinction at a defined temperature and at a wave-length of 450 nm was lowerthan 0.05 (which means a complete transparency) against a xylene solution containing the same substance in the same concentration. In a number of the cases a negative extinction value was obtained, a fact show¬ ing that a microemulsion system may be purer, more "shiny" than the true solution. This is visible to the naked eye at extinction values lower than -0.1. The compositions according to the invention are illustrated by the following non-limiting Examples. Example 1 Parts 0,0-Diethyl 0-(2-quinoxalinyl) thio- phosphate 25 Xylene 25 Nonylpheπol polyglycol ether (E0=1Q) 18 Ethyl acetate 20 Water 12 This composition shows an extinction of -0.18 at 30 C; a lower cloud point of 24 °C and an upper cloud point of 50 °C. Example 2 Parts 0,0-Diethyl 0-(2-quiπoxaliπyl) thio- phosphate 25 Xylene 25 Noπylphenol polyglycol ether (EO = 10) 30 Water 15 Cyclohexanone 5 This composition shows an extinction of 0.01 at 30 C; a lower cloud point of 26 C and an upper cloud point of 48 °C. Example 3 Parts 0,0-Diethyl 0-(2-quiπoxaliny1) thio- phosphate 2 Xylene 25 Nonylphenol polyglycol ether (E0=10) 40 Water 10 This composition shows an extinction of -0.07 at 30 °C; a lower cloud point below -5 °C and an upper cloud point of 54 °C. Example 4 Parts 0,0-Diethyl 0-(2-quiπoxalinyl) thio- phosphate 25 Xylene 25 Block copolymer formed from polyethylene oxide and polypropylene oxide with a molecular weight of about 1500 30 Water 2Q * This composition shows an extinction of -0.315 at 30 °C; a lower cloud point below -5 °C and an upper cloud point of 53 C. Example 5 Parts 0,0-Diethyl 0-(2-quinoxaliπyl) thio- phosphate 25 Xylene 32 Block copolymer formed from polyethylene oxide and polypropylene oxide with a molecular weight of about 1500 16 Water 17 Ethyl acetate 10 This composition shows an extinction of -0.085 at 30 C; a lower cloud point of 28 °C and an upper cloud point of 58 °C. Example 6 Parts 0,0-Diethyl 0-(2-quiπoxalinyl) thio- phosphate 25 Xylene 30 Water 17 Ethaπol 10 Block copolymer formed from polyethylene oxide and polypropylene oxide with a molecular weight of about 1500 18 This composition shows an extinction of -0.032 'at 30 °C a lower cloud point or 3 C and an upper cloud point of 53 C. Example 7 Parts 0,0-Dilauryl hydrogen phosphate 20 0-Lauryl dihydrogen phosphate 20 Water 50 Block copolymer formed from polyethylene oxide and polypropylene oxide with a molecular weight of about 1500 10 This composition shows an extinction of 0.03 at 35 C; a lower cloud point of 32 °C and an upper cloud point of 75 °C. Example 8 Parts 0,0-Diethyl 0-(2-quinoxaliπyl) thio- phαsphate 25 Xylene 25 Block copolymer formed from polyethylene oxide and polypropylene oxide with a molecular weight of about 1500 10 Ethyl acetate 30 Water 10 This composition shows an extinction of 0.0 at 25 C; a lower cloud point of 16 °C and an upper cloud point of 55 C. Example 9 Parts 0,0-Dioctyl hydrogen phosphate 40 0-Octyl dihydrogeπ phosphate 40 Water 15 Monylpheπyol polyglycol ether (E0=10) 5 This composition shows an extinction of 0.01 at 25 C; a lower cloud point of 8 °C and an upper cloud point of 32 °C. Example 10 Parts 0,0-Diethyl 0-(2-quinoxaliπyl) thio- phosphate 25 Nonylpheπol polyglycol ether 70 Water 5 This composition shows an extinction of -0.03; a lower cloud point below -5 C and an upper cloud point of 65 °C. Example 11 Parts 0,0-Diethyl 0-(2-quinoxaliπyl) thio- phosphate 25 Noπylpheπyol polyglycol ether 70 Water 2 Ethaπol 3 This composition shows an extinction of -0.135; a lower cloud point below -5 C and an upper cloud point of 61 °C. Example 12 Parts 0,0-Diethyl 0-(2-quiπoxaliπyl) thio- phosphate 25 (contd . ) Block copolymer formed from polyethylene oxide and polypropylene oxide with a molecular weight of about 1500 24 Cyclohexanone 1 Water 50 This composition shows an extinction of 0.02 (separates to two phases without cyclohexanone); the lower cloud point is 28 °C, the upper cloud point Is 31 α C. . Example 13 Parts 0,0-Diethyl 0-(2-quiπoxaliπyl) thiophosphate 25 Oleyl alcohol polyethyleneglycol ether (E0=15) 5 Ethyl acetate 50 Water 20 This composition shows an extinction of -0.06 at 25 C; a lower cloud point of -1 °C and an upper cloud point of 28 °C. Example 14 Parts 0,0-Dibutyl hydrogen phosphate 13 O-n-Butyl dihydrogen phosphate 13 Ethoxylated tristyrylpheπol (E0=20) 5 Ethyl acetate 19 Water 50 This composition shows an emulsifier extinc- tion of -0.12 at 25 °C; a lower cloud point of -2 °C and an upper cloud point of 56 C

Claims: What we claim is: 1. A plant-protective microemulsioπ composi¬ tion containing a phosphoric acid ester and/or thio- phosphoric acid ester as active ingredient, which com¬ prises: 20 to 80 % by weight of active ingredient; 5 to 70 % by weight of a nonionic surface active agent, preferably a block copolymer with a molecular weight of 1000 to 10000 formed from polyethylene oxide and polypropylene oxide, an alkylphenol polyglycol ether, ethoxylated fatty alcohol or a mixture of nonionic surface active agents; 2 to 50 % by weight of water; if desired, 1 to 50 % by weight of a co-surfactant, preferably C, „ straight or branched chain and/or cyclic alcohol, C, g straight or branched chain and/or cyclic ketone, esters of C,_ ≤ fatty acids with C, , alcohols or the mixture thereof; and if desired, 15 to 30 % by weight of a water-immiscible organic solvent.

Inventors: ANGYAN SANDOR, DETRE TAMAS, KISS EVA, MARMAROSI TAMASNE, PAL JOZSEFNE, PAP LASZLO, PINTER JANOS, SHUESZLER ERZSEBET, SZEGOE ANDRAS, ANGYAN, SANDOR, DETRE, TAMAS, KISS, EVA, MARMAROSI, TAMASNE, PAL, JOZSEFNE, PAP, LASZLO, PINTER, JANOS, SHUESZLER, ERZSEBET, SZEGOE, ANDRAS
Applicants: CHINOIN GYOGYSZER ES VEGYESZET, CHINOIN GYOGYSZER ES VEGYESZETI TERMEKEK GYARA RT
Application year: 1988
Main classification: A01N25
IPC codes: A01N25, A01N57, B01F17