Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
  • A01N25/02—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests containing liquids as carriers, diluents or solvents
  • A01N25/04—Dispersions, emulsions, suspoemulsions, suspension concentrates or gels
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
  • A01N25/30—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests characterised by the surfactants
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K23/00—Use of substances as emulsifying, wetting, dispersing, or foam-producing agents
  • C09K23/017—Mixtures of compounds

Definitions

• This invention relates to chemical formulations which are useful as water-miscible preparations of compounds which are normally regarded as water-insoluble and to their use as pesticidal formulations.
• the invention in particular, relates to formulating water-insoluble oil-soluble substances in water as small particles whose Z average mean size particle size is less than 200 nm.
• the Z average mean size can be defined as the model free mean of light scattering.
• formulations include microemulsions, micellar solutions and molecular solutions.
• Microemulsions are in themselves known. They are one of three identified types of dispersion (as distinct from a molecular solution) of oil, water and surfactant. (The term “oil” is used in this specification to mean any non-aqueous solvent in which a substance of interest is soluble and which is immiscible with water.) These three types of dispersion are: microemulsions, micellar solutions and normal emulsions (or macroemulsions) .
• Macroemulsions appear white or opaque and are characterised by their property to separate into their two original liquid phases on standing; the average particle diameter will generally be above 200 nm. Microemulsions and micellar solutions are translucent and do not separate. Microemulsions can be considered as having average droplet (or particle) diameters of from 10 to 200 nm, micellar solutions as having average particle diameters of from 2 nm to 10 nm and molecular solutions as having average particle diameters of less than 2 nm. Recent evidence, however, does suggest that microemulsions with droplet diameters below 10 nm are possible.
• microemulsions can be of the water-in-oil (w/o) or oil-in-wa ' ter (o/w) type and can be made to invert from one to another.
• One of the best means of differentiating between formulations in accordance with the invention and macroemulsions (and between microemulsions, micellar solutions and molecular solutions) is on the basis of particle or droplet size (usually measured as averages) .
• Average particle or droplet size may be measured with a laser particle sizer, such as the MALVERN AUTOSIZER 2c (Malvern Instruments, Malvern, Hereford & Worcester) using glass cells as sample containers.
• nmr measurements are used to resolve theoretical questions regarding the state or location of molecules in microemulsions.
• the line width for protons in molecules can indicate freedom of the molecules to thermal motion, the broadening of the line indicating greater restriction of motion.
• the chemical shift of water is different when it is distributed in spheres or in cylindrical or lamellar micelles.
• Other studies are possible using nmr, in addition.
• FR-A-2187226 corresponds to CA-A-1007985 and discloses insecticidal compositions comprising an anionic surfactant and a hydrotrope.
• FR-A-1026169 discloses various emulsions, which may be useful in formulating insecticides comprising an alkylsulphonate surfactant and a polar compound such as an alcohol, an amino, a phenol or an acid.
• US-A-3954967 discloses "microcolloids" containing a resin and a polar solvent.
• EP-A-0062181 corresponds to US-A-500348 and relates to apparently conventional emulsions containing high HLB surfactants.
• EP-A-0107009 corresponds t CA-A-1209361 and relates to a development of the subject matter disclosed in EP-A-0062181; again, emulsions containing high HLB surfactants are disclosed.
• EP-A-0149051 corresponds to US-A-4737520 also discloses certain emulsion formulations.
• US-A-4567161 discloses liquid active ingredient concentrates for the preparation of microemulsions.
• the microemulsions are stated to be oil-in-water microemulsions.
• the coemulsif iers are a particular class of glycerin esters having HLB (Hydrophilic/Lipophilic Balance) values of between 12 and 18.
• HLB Hydrophilic/Lipophilic Balance
• the formulations of US-A-4567161 are said to have special significance for pharmaceutical active substances.
• the active ingredient can be a number of other substances including herbicides (a number of which are listed) , fungicides, insecticides, acaricides, nematocides or plant growth regulators. No specific fungicides, insecticides, acaricides, nematocides or plant growth regulators are disclosed or even suggested.
• WO-A-8807326 published on 6th October 1988 and incorporated herein by reference, specifically relates to microemulsions and related compositions comprising an aqueous phase, an oil phase, a surfactant and a cosurfactant which is an ethylene oxide propylene oxide block copolymer (as typified by certain members of the PLURONIC PE or PLURIOL PE range from BASF) .
• a water-miscible formulation whose average particle size is at most 200 nm, the formulation comprising water, oil, a surfactant and a wetting agent.
• the formulation is a microemulsion
• the microemulsion will generally be clear or translucent, except in the viscoelastic gel phase. Micellar solutions and molecular solutions may additionally be clear. Both phases will usually be liquid.
• the water can be tap water, although distilled water can be used.
• the amount of water in the microemulsion will depend on many factors but typically for w/o microemulsions will be from 20 to 70% w/v and for o/w microemulsions it shall be from 40 to 95% w/v.
• the oil need not merely be an "oil” in the sense of a petroleum ' fraction, although such oils are included; the term “oil” is used to mean any non-aqueous solvent in which a substance of interest is soluble and which is immiscible with water; alternatively, the substance of interest may itself be the oil.
• the oil may be animal, vegetable, mineral or silicone or some other organic solvent which is water-immiscible, such as an optionally halogenated hydrocarbon.
• the hydrocarbon may be aliphatic or aromatic or have both aliphatic and aromatic moieties.
• Typical solvents include xylene, naphthalene, kerosene, isoparaffins and halogenated hydrocarbons.
• the surfactant may be any typical emulsifier as found in most macroemulsion systems.
• the surfactant may be anionic, cationic, zwitterionic or nonionic.
• Anionic surfactants are more frequently used.
• Suitable anionic surfactants include hydrocarbon sulphates, sulphonates and sulphamates, especially compounds wherein the hydrocarbon moiety is an alkyl or alkylaryl group. Soaps (hydrocarbyl carboxylates) can also be used, as can sulphocarboxylic acids such " as sulphosuccinic acid.
• anionic detergents examples include alkyl benzene sulphonates and sulphonic acids such as C 8 to C 16 alkyl benzene sulphonates and sulphonic acids including dodecyl benzene sulphonic acid (a predominately straight chain mixture of which compounds is sold under the trade mark NANSA SSA) .
• Anionic surfactants which are acids, as opposed to salts, may in general be found to be preferable.
• an appropriate surfactant can be made by one of skill in the art without undue experimentation.
• the oil is aromatic, such as xylene or naphthalene
• a surfactant having an aromatic moiety for example an alkyl benzene sulphonate or an alkyl naphthalene sulphonate.
• an aliphatic surfactant is preferred such as an alkyl sulphonate or a dialkyl sulphosuccinate (such as dioctyl sulphosuccinate) or a soap.
• an alkyl sulphonate or a dialkyl sulphosuccinate (such as dioctyl sulphosuccinate) or a soap.
• a dialkyl sulphosuccinate such as dioctyl sulphosuccinate
• soap Another factor in determining the choice of surfactant is the type of microemulsion (w/o or o/w) to be produced.
• HLB surfactants for example having an HLB of from 4 to 9 , part i cul arly 4 to 7 ) tend to stab i l i s e w/ o microemulsions and should therefore for preference be used for w/o microemulsions and high HLB surfactants ( f or exampl e having an HLB of f rom 9 to 20 , particularly 9 to 20 ) tend to stabi l i se o/w microemulsions and should thus be used for o/w microemulsions .
• HLB values may be measured by standard techniques .
• PIT phase inversion temperature
• This system is based upon the temperature at which a surfactant causes an o/w emulsion to invert into a w/o emulsion. It provides information concerning the types of oils, phase volume relationships and the concentration of surfactant which could be used. This system is established on the proposition that the HLB of a nonionic surfactant changes with temperature; the inversion of an emulsion type occurs when the hydrophilic and lipophilic tendencies of the surfactant just balance. No emulsion forms at this temperature.
• Emulsions stabilised with nonionics tend to be o/w types at low temperatures and w/o types at high temperatures. From the microemulsion standpoint, the PIT system has a useful feature in that it can throw light on the chemical type of surfactant preferred to match a given oil.
• Wacer-miscible formulations in accordance with the first aspect of the invention include a wetting agent.
• wetting agents are surface active agents which lower the surface tension of water by a considerable amount, although they may be present only in very low concentration. It is well within the competence of those skilled in the art to determine whether a particular surface active agent (surfactant) is a wetting agent or not.
• Preferred wetting agents are those for which a 1% (v/v if liquid or w/v if solid) solution in water have a surface tension at 25°C of less than 50 mN.m "1 , particularly less than 40 mN.m -1 and preferably below 35 or 30m N.m “1 . (Pure water has a surface tension of 73 mN.m " at 25°C.)
• Preferred wetting agents include polysiloxane-based copolymers.
• Polysiloxane-polyether-copolymers are particularly preferred such as the TEGOPLANT WT series available from Th. Goldschmidt AG, Essen, West Germany. (The word TEGOPLANT is a trade mark.)
• the copolymers TEGOPLANT WT 10 and TEGOPLANT WT 25 are especially preferred, with TEGOPLANT WT 10 being the most preferred.
• a 1% (v/v) solution of TEGOPLANT WT 10 has a surface tension at 20.3 mN.m "1 at 25°C and a 1% (v/v) solution of TEGOPLANT WT 25 has a surface tension of 22.6 mN.m "1 at 25°C.
• the HLB of the polysiloxane-based copolymer may be below 10 and possibly below 5.
• the wetting agent may constitute the cosurfactant or the formulation may contain one or more additional cosurfactants. Two classes of additional cosurfactants are normally preferred for use, although others may be used. Aliphatic alcohols (particularly primary aliphatic alcohols) are a first preferred class. They may have a carbon content of from 5 to 12 or more carbon atoms.
• Lower homologues for example C 5 to C 7 alcohols are used to stabilise certain formulations, including w/o microemulsions and alcohols above C 8 (optionally including C g ) tend to be used to stabilise other formulations, including o/w microemulsions.
• Nonionic surfactants form a more versatile group of additional cosurfactants. They can be balanced with the primary surfactant to give systems that are stable as micellar solutions and as both w/o and o/w microemulsions.
• a whole range of nonionics can be used, including ethylene oxide propylene oxide block copolymers (as typified by the PLURONIC PE or PLURIOL PE range from BASF) and alcohol ethoxylates (as typified by the DOBANOL range from Shell) .
• the HLB of the additional cosurfactant may be less than 10 or even less than 5.
• one nonionic cosurfactant is the ethylene oxide propylene oxide block copolymer containing 10% ethylene oxide sold under the trade mark PLURONIC PE 6100 or PLURIOL PE 6100, which has an HLB of 3.0.
• Other suitable HLB values for cosur actants are less than 3, for example about 2 or even about 1.
• ⁇ • two dimensional spreading pressure in the monolayer of adsorbed species.
• micellar solutions micellar solutions and molecular solutions
• broad and preferred ranges of the ingredients may be as follows:
• Oil (including dissolved substance if any) 20 to 50% 30 to 40%
• the amounts of surfactant and cosurfactant should be kept as low as possible and the amount of water should be kept as high as possible.
• the above is subject always to the proviso that the total number of percentage parts of the ingredients cannot exceed 100.
• the broad and preferred concentration ranges of the ingredients can be as follows: Ingredient Broad w/v Preferred w/v
• Oil (including dissolved substance if any) 1 to 20% 1 to 10%
• a water-insoluble oil-soluble substance which it is desired to formulate may be dissolved in the oil, although it is clear that the oil may itself be the water-insoluble oil soluble substance.
• This "substance of interest" can be anything which is convenient to be formulated in this manner (including other solvents) .
• pesticides in particular insecticides and/or acaricides
• synthetic pyrethroids and fungicides and herbicides are particular candidates for formulation by means of the present invention.
• deltamethrin is the common name for 3- (2 , 2-dibromoethenyl) -2 , 2-dimethyl- cyclopropane carboxylic acid cyano (3-phenoxyphenyl) - methyl ester.
• Deltamethrin is a potent synthetic pyrethroid pesticide, the preparation of the racemic mixture of which is described in DE-A-2439177.
• Deltamethrin is insoluble in water, but is soluble in organic solvents such as ethanol, acetone, dioxane, xylene and certain petroleum fractions.
• Other synthetic pyrethroids include cypermethrin (3- (2 , 2-dichloroethenyl) -2 , 2 -dimethyl eye lop ropane- carboxylic acid cyano(3-phenoxyphenyl ⁇ -methyl ester) , permethrin (3- (2, 2-dichloroethenyl) -2, 2-dimethylcyclo- propanecarboxylic acid ( 3 -phenoxypheny 1 ) -methyl ester) and fenvalerate (4-chloro-alpha- ( 1-methylethyl) - benzeneacetic acid cyano( 3 -phenoxyphenyl) methyl ester.
• Cypermethrin may be prepared as described in DE-A-2326077, permethrin may be prepared as described in DE-A-2437882 and DE-A-2544150 , and fenvalerate may be prepared as described in DE-A-2335347.
• natural pyrethroids, organophosphorus compounds and carbamates are examples of other pesticides us,eful in the present invention.
• Such other pesticides include non-pyrethroid insecticides and acaricides (such as organophosphorus compounds) and herbicides and fungicides.
• Organophosphorus compounds include chlorpyritos (Q .
• Pesticides for example mixtures of pyrethroids or mixtures of pyrethroi ( s ) and organophosphorus compound(s)
• Cypermethrin is an example of a liquid which can function both as the oil and as a water-insoluble oil-soluble substance.
• either the oil is a pesticide or the formulation comprises a pesticide dissolved in the oil.
• the oil is a pesticide
• the formulation may be free of an oily solvent for the pesticide ⁇ It is preferred that the cosurfactant has an HLB of less than 12.
• the pesticide may be a pyrethroid or any other insecticide, acaricide, herbicide or fungicide.
• Pesticidal formulations in accordance with the invention can show enhanced activity not only compared to conventional (macroemulsion) formulations but also when compared with other microemulsion formulations, because of the presence of the wetting agent.
• micellar solutions With water-in-oil microemulsions, micellar solutions and molecular solutions, it is generally possible to get a higher concentration of the substance of interest (for example deltamethrin or another synthetic pyrethroid or other pesticide) .
• the substance of interest for example deltamethrin or another synthetic pyrethroid or other pesticide
• o/w formulations may give a perfectly adequate concentration for end use or even for concentrates for dilution before use.
• a formulation in accordance with the first or second aspect is prepared by mixing the ingredients.
• the ingredients will tend to form a microemulsion, micellar solution or molecular solution.
• kinetic considerations may dictate that some agitation is preferably used to assist the mixing. Agitation may be by magnetic or mechanical means or in some cases ultrasonic.
• the wetting agent and additional cosurfactant, if any, is added and the system is agitated to produce a clear o/w microemulsion.
• Routine modifications such as the " application of heat or altering the degree of agitation can be made to these basic processes to suit the system in use.
• a method of controlling pests comprising applying a pesticide in a formulation whose average particle size is at most 200 nm and which comprises water, a pesticidal oil, a surfactant and a cosurfactant comprising a polysiloxane based copolymer.
• the formulation may be a microemulsion, a micellar solution or a molecular solution; the microemulsion may be an o/w or a w/o formulation. Oil-in-water microemulsion formulations are preferred. Pyrethroid or other pesticides formulated in this way can be used to control pests in an agricultural environment.
• pyrethroid or other (for example, organophosphorus) pesticide formulations are not confined to agriculture: public health formulations may be commercially important.
• Agricultural formulations in accordance with the invention may have a further advantage in that they use less potentially harmful solvent (such as xylene) per dose than certain conventional formulations, thereby posing less of a threat to the crop being treated, the handler and to the environment in general.
• the concentration of the substance of interest (for example, deltamethrin) in the formulations of the invention may range from as little as 0.1 ppm, 0.01 g/1 or 0.1 g/1 up to 100 or 200 g/1 or more.
• High concentrations of pesticide may range from 10 to 300 g/1, for example 25 to 200 g/1, such as 25 or 100 g/1.
• deltamethrin or another pyrethroid pesticide 10 to 50 g/1 or 100 g/1 final concentration may be found to be suitable.
• a formulation containing from 0.1 ppm or 0.05 g/1 to 5 g/1, for example 0.1 g/1 to 1 g/1 may be found to be acceptable.
• a f ormul ation was prepared from the fol l owing ingredients :
• a formulation was prepared from the following ingredients:
• 5g deltamethrin were made up to 80 ml with xylene, and the resulting mixture was placed in a 250 ml beaker.
• the TEGOPLANT WT 10 and PLURIOL PE 6100 cosurfactants and NANSA SSA surfactant were then slowly dissolved into this and the appropriate amount of water (69.0 mis) added slowly from a burette while stirring.
• the formulation was confirmed to be a micellar solution by conductivity measurements.
• the average particle size of a 1/400 dilution was measured by a MALVERN AUTOSIZER 2c laser particle sizer to be about 40 nm, showing the diluted formulation to be a microemulsion.
• a formulation was prepared as in Example 1, except that the TEGOPLANT WT 10 wetting agent was omitted.
• Example 2 The activity of the formulation of Example 1, diluted appropriately with water, was tested against Rl Mvzus persicae by spraying the aphids direct from a Potter tower. As a comparison a standard AMBUSH C e ulsifiable concentrate, also diluted with water. (The word AMBUSH is a trade mark for a conventional cypermethrin formulation.)
• Example 1 100 100 100 100 84 64 AMBUSH 100 100 - 36 41
• Example 1 100 100 100 100 100 97 67 AMBUSH 100 100 - - 36 41
• results show that greater mortality resulted from a composition in accordance with the invention than from a conventional emulsifiable concentrate.
• results also show that the composition in accordance with the invention had greater persistence than the conventional formulation as the pesticidal effect lasted beyond 48 hours.
• each individual weevil in each dish was examined and scored into one of three categories: 'healthy' apparently unaffected by insecticide; 'weak' immobile, lying or dorsum but still moving at least when prodded; 'dead' - immobile and unresponsive.
• Table 2 Mean percentage mortality of vine weevil adults 7 days after treatment.
• Example 1 Unsprayed - 10 6
• the formulation of Example 1 is significantly more active than the conventional AMBUSH formulation at a comparable concentration of active ingredient. Further, the formulation of Example 1 is more active than the formulation of Comparative Example l, which although it is a microemulsion formulation does not contain a wetting agent.

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Citations (8)

• 1988
  • 1988-09-30 GB GB888822937A patent/GB8822937D0/en active Pending
• 1989
  • 1989-09-29 EP EP89911581A patent/EP0436651A1/en not_active Withdrawn
  • 1989-09-29 GR GR890100622A patent/GR1000535B/el unknown
  • 1989-09-29 WO PCT/GB1989/001159 patent/WO1990003111A1/en not_active Application Discontinuation
• 1991
  • 1991-03-26 NO NO91911243A patent/NO911243L/no unknown
  • 1991-03-27 DK DK056691A patent/DK56691A/da unknown
  • 1991-03-28 FI FI911554A patent/FI911554A0/fi not_active Application Discontinuation

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