The present invention relates to a stable emulsion, uses of and methods of preparing the same. It also relates to such an emulsion which is a ready-mix emulsion; to use of such an emulsion for regulating plant growth; and to use of such an emulsion for preventing and/or reducing lodging of crop plants.

WO 2020/173675 Al describes an emulsion comprising of an aqueous phase comprising an agrochemical A and an oil phase comprising agrochemical B. Agrochemical A being mepiquat salt and agrochemical B being trinexapac-ethyl

However, the compositions described therein have been found to degrade at a lower pH, which then leads to the irreversible formation of a gel.

It has surprisingly been found that most polymers were unsuitable for formation of emulsions under low pH conditions.

The present invention therefore provides a stable emulsion comprising:

(i) an aqueous phase comprising an agrochemical A selected from salts of mepiquat, salts of chlormequat, and mixtures of such salts; and

(ii) an oil phase comprising trinexapac-ethyl; and

(ill) hydroxyethyl cellulose (HEC); where either phase (i) is dispersed in phase (ii); or phase (ii) is dispersed in phase (i).

Preferably the emulsion is not a microemulsion.

HEC has been found to be less affected by pH conditions and does not degrade in acidic conditions, forms less foam under high agitation when diluted in more water and is easier to dissolve in water. These properties help with the manufacturing and characteristics of the end product.

The molecular weight of the HEC is preferably from 1,000 to 10,000,000, such as from 5,000 to 5,000,000, from 5,000 to 1,000,000, from 6,000 to 400,000, from 7,000 to 300,000, from 8,000 to 200,000 or even from 8,000 to 50,000 or from 8,500 to 15,000. The HEC may be functionalised or unfunctionalized. If functionalised, the HEC is preferably Cetyl- functionalised.

Preferably, the emulsion is stable at a range of temperatures, including from 20 to 50 °C, e.g., 25 to 40 °C.

By 'stable' we mean that the emulsion exhibits no significant droplet growth and/or gel formation. Advantageously, the described compositions are stable for at least one day, such as at least one month, preferably at least six months.

The emulsion preferably comprises HEC in an amount of from 0.5 to 25 g/L, such from 0.6 to 22 g/L, from 0.7 to 20 g/L from 0.8 to 18 g/L, from 0.9 to 16g/L, from 1 to 15 g/L, from 1.2 to 14g/L, from 1.5 to 12 g/L, or preferably from 2 to 10 g/L.

The formulation is advantageously stable at a pH of from 1 to 7, such from 1.1 to 6, from 1.2 to 5, from 1.3 to 4, 1.4 to 3, or most advantageously from 1.5 to 2.

When phase (i) is dispersed in phase (ii) the emulsion is a water-in-oil emulsion (EO); when phase (ii) is dispersed in phase (i) the emulsion is an oil-in-water emulsion (EW).

Advantageously phase (ii) is dispersed in phase (i) and the emulsion is an oil-in-water emulsion (EW).

Preferably, agrochemical A is selected from mepiquat chloride and chlormequat chloride; more preferably it is mepiquat chloride.

An emulsion is a dispersion of one liquid in a second liquid continuous phase, where the two liquids concerned are essentially immiscible, or have limited mutual miscibility. To form an emulsion, the two immiscible phases are mixed while supplying sufficient energy to cause one phase to break up into droplets dispersed in the second phase. The energy input may take different forms such as stirring, ultrasound or repeated forced flow through narrow orifices.

The basic factor in the stability or instability of an emulsion is the degree of interfacial tension (i.e. free energy) between the droplets of the dispersed liquid and the other continuous liquid phase. By comparison, a microemulsion is a thermodynamically stable, isotropic liquid mixture of a water- immiscible organic solution, water and surfactant, wherein the microemulsion is formed spontaneously upon simple mixing of the components.

Due to a less favourable interfacial tension, oil-in-water (EW) and water-in-oil (EO) emulsions are thermodynamically unstable and will coalesce over time leading to phase separation. To slow down coalescence of the emulsion droplets, the emulsion droplets can be stabilised by adding emulsifiers.

Such emulsifiers may be surfactants, polymers or solid particles, which adsorb at the liquid/liquid interface. Emulsifiers reduce the interfacial tension between the phases facilitating the formation of emulsion droplets. They also form a physical barrier, which prevents the emulsion droplets from coalescing.

Surfactants are compounds which reduce the surface tension of water. Examples of surfactants are ionic (anionic, cationic or amphoteric) and nonionic surfactants. Surfactants can also be used as emulsifiers. Emulsions according to the invention typically comprise at least one surfactant (one, two, three or more surfactants).

Suitable ionic surfactants are the alkali, alkaline earth and ammonium salts of aromatic sulfonic acids, for example of lignosulfonic acid, phenolsulfonic acid, naphthalenesulfonic acid, dibutylnaphthalenesulfonic acid or of fatty acids, alkyl- and alkylarylsulfonates, alkylsulfates, lauryl ether sulfates and fatty alcohol sulfates, and salts of sulfated hexa-, hepta- and octa-decanols, and of fatty alcohol glycol ethers, condensates of sulfonated naphthalene and its derivatives with formaldehyde, condensates of naphthalene or of the naphthalenesulfonic acids with phenol and formaldehyde, polycarboxylates or phosphate esters of alkoxylated alcohols.

The oil phase comprises a liquid that does not substantially dissolve or become miscible with water. Examples of suitable oils for use as the oil phase include but are not limited to vegetable oils, methylated vegetable oils, aromatic oils and hydrocarbon solvents (for examples aromatics or aliphatic esters). The trinexapac-ethyl may itself be an oil or may be solubilised in a hydrophobic solvent to form an oil phase or may be dispersed in the oil phase or absorbed to the interface of the oil and aqueous phase of the present invention. Typically, trinexapac-ethyl will be present in the emulsion at from 25g/l to 150g/l, suitably from 33g/l to 100g/l.

Typically, Agrochemical A will be present in the emulsion at from 200g/l to 600g/l, suitably from 225g/l to 500g/l.

Suitably trinexapac-ethyl is present in the emulsion at from 50g/l to 100g/l whilst mepiquat chloride is present in the emulsion at from 225g/l to 450g/l.

Suitably trinexapac-ethyl is present in the emulsion at from 33g/l to 5 Og/I whilst chlormequat chloride is present in the emulsion at from 400 to 600g/l (preferably 500g/l).

Generally, any agrochemically active ingredient will be present at a concentration of from about 0.000001% to about 90% w/w; preferably from about 0.001% to about 90% w/w. Agrochemical compositions of the invention may be in the form of a ready-to-use formulation or in concentrate form suitable for further dilution by the end user, and the concentrations of agrochemicals and the blend of (i) plus (ii) will be adjusted accordingly. In concentrated form, compositions of the invention typically contain, independently, Agrochemical A and trinexapac-ethyl, each at from 1% to 90% w/w, more preferably from 2% to 75% w/w, even more preferably from 3% to 50% w/w, of the total composition.

The compositions of the present invention may relate to concentrates designed to be added to a farmer's spray tank of water or they may be applied directly without further dilution. The present invention also relates to compositions produced in a farmer's spray tank of water when a concentrate is mixed with water in the spray tank.

The compositions of the present invention may include other ingredients such as a viscosity modifier, an anti-foam agent, an anti-bacterial agent, a colourant or a perfume.

A composition of the present invention may be in the form of a ready-mix emulsion formulation, packaged within a single vessel and ready to use directly after dilution. The invention also contemplates capsule suspension formulations prepared by emulsion polymerisation. Compositions of the present invention may be used in a method for regulating plant growth comprising applying to one or more plants an effective amount of the composition.

Compositions of the present invention may be used in a method for preventing and/or reducing lodging of crop plants comprising applying to one or more plants an effective amount of the composition.

Compositions of the present invention may be used in a method for enhancing roots system comprising applying to one or more plants an effective amount of the composition.

The above methods may involve one or more plants which are oilseed rape or monocotyledonous plants, preferably selected from cereals, rice, maize and sugar cane; more preferably the plants are cereal plants.

The above methods may involve an effective amount of the composition applied at a rate of from 0.5 to 5 l/ha, more suitably from 1 to 3 l/ha.

The present invention also provides a method of preparing an emulsion as defined herein. Preferably, the HEC is added directly as a solid at the same time as Agrochemical A into the aqueous phase.

The present invention further provides the use of hydroxyethyl cellulose (HEC) to inhibit the formation of a gel from an emulsion, advantageously an emulsion as defined herein.

Unless otherwise stated are percentages are given as percentages by total weight and all embodiments and preferred features may be combined in any combination.

The invention is described by the following non-limiting Examples.

Examples

Methodology

A 250 ml vessel was charged with mepiquat chloride (45.6 g), the polymer to be tested (1.0 g) and water (39.7 g). The mixture was stirred with a paddle stirrer until the solids had completely dissolved. A 50%w/w solution of trinexapac-ethyl in Solvesso® 200ND (20.0 g) was mixed in with a Silverson® high-shear mixer (6500 rpm), while maintaining the temperature below 25 °C and pH at 1 to 2.5.

If an emulsion was visually observed (by visual inspection to see if two distinct phases were observed) the size of the droplet formed was measured.

The sample were then left undisturbed at room temperature (circa. 25 °C) for the specified quantity of time and visually inspected.

The results are set out in Table 1.

Table 1

It can therefore be seen that only emulsions formed with HEC are stable at a pH of 1 to 2.5 under ambient conditions.

The invention is defined by the claims.