Gel formulations

GEL FORMULATIONS

The invention relates to new water dispersible containerisation systems containing organic gels.

The containerisation systems are suitable for containing hazardous products rendering them safe to handle and not

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hazardous to the environment.

At present, most hazardous liquids are stored in metal drums or, where smaller quantities are required, in plastic containers..

Hazardous compounds, especially agrochemical compounds are formulated in various compositions. Liquid compositions are most convenient for farmers because of the relative ease with which they can be handled. ' There are, nevertheless, difficulties in handling such liquid compositions. There is a danger of spillage or leakage if there are holes in previously used containers or if they are dropped. Although secure containers resistant to shock can be used, in the event of an accident, for example during transportation, the risk remains of spillage or • leakage with rapid loss of liquid, for example, leakage onto the ground.

It has been difficult to provide a formulation and a containerization system (i.e., container) which safeguards those handling it, including farmers and transporters, and protects the environment.

It is known to provide agrochemicals in soluble bags or sachets, but that does not completely avoid the possibility of the bag cracking and breaking and the liquid creating a contamination problem. More specifically, when water .soluble bags are used, the solvent from the solvent-based agrochemicals tends to more or less extract the adjuvant or additives from the

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I s / film and render the wall (film) of the bag more brittle (especially at low temperatures and more specifically at temperatures below 0°C). This reduces the life time of the bag.

The present invention seeks to provide containerization systems to contain hazardous compounds such as agrochemicals, which systems are safe for everybody, especially farmers and other persons who handle the hazardous compounds.

The present invention also seeks to provide containerization systems for hazardous compounds e.g. agrochemicals which are readily, rapidly and easily soluble and/or dispersible in water, preferably in less than ten minutes, more preferably in less than five minutes under normal agitation. This is a problem which is especially difficult to overcome because an increase of viscosity is often connected with increased difficulty in forming the water dispersions.

The invention also seeks to provide containerization systems containing formulations for hazardous compounds e.g. agrochemicals which are condensed as much as possible, thus requiring the least amount of space.

The present invention also seeks to provide containerization systems for hazardous compound (e.g., agrochemicals) which diminish the risks of pollution.

The present invention also seeks to provide containerization systems for smelly or stinking compounds so as to reduce or cancel the odours.

The invention also seeks to avoid breakage of containers which contain hazardous, e.g. agrochemical, formulations. When the containers are rigid, there is

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t substantial possibility of simple breakage. With a liquid in a bag this possibility is somewhat reduced, but the liquid still transmits the shocks and there is a problem of a hydraulic hammer effect. The invention also seek to avoid, or at least to partially reduce, this hydraulic hammer effect.

The invention also seeks to provide containerisation systems for hazardous compounds such as agrochemicals, e.g. pesticides, plant protection and plant growth regulators which contain formulations which dissipate, as much as possible, the energy of a shock to a container from outside providing shock absorbing formulas

The invention seeks to provide a new formulation system for agrochemicals which reduces the risks of clogging the spray nozzles or the filters of spray tanks.

The present invention provides a containerisation system comprising a water-dispersible organic gel in a water soluble or water dispersible bag, wherein the gel comprises (a) an effective amount of a hazardous product (b) an effective amount of a water-soluble or water dispersible surfactant, (c) an effective amount of an acrylic acid polymer or copolymer, optionally in the form of a salt and optionally cross-linked and (d) from 0.05 to 5% by weight water.

The gels referred to above are especially suitable for containment in water-soluble or water ί

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WO 92/01377

PCT/EP91/01351

- 4 dispersible bags. The water-dispersible organic gel may be a continuous system. The water-dispersible organic gels comprise a hazardous product (e.g., an agrochemical, preferably a pesticide, a plant protection agent, or a plant growth regulator) as the active ingredient; a water-soluble or water dispersible surfactant; a polyacrylic acid polymer, optionally in the form of a salt or a copolymer and optionally cross-linked (eg. partially cross-linked) and from 0.05 to 5%, preferably from, 0.5 to 2.5% of water.

As used herein, surfactant means an organic material which is able to substantially reduce surface tension of water.

Surfactants useful herein may be non-ionic, anionic, cationic or zwitterionic. One surfactant, or a mixture of surfactants may be used. Amphoteric surfactants may be used. Preferably, the surfactant is able to form, at above 70°C or preferably at above 50°C, a liquid mixture, preferably a liquid phase with the hazardous product and organic solvent if present. This liquid mixture may be a single continuous phase or in the form of an emulsion.

Preferably, at least 10% of the surfactant contains hydroxy and/or alkoxy groups, such as polyethoxylated or polyproixylated derivatives, especially the derivatives of fatty amines or fatty acids or fatty alcohols or aryl phenols.

The polyacrylic acid polymers which may be used herein are preferably compounds which are water-soluble or waterSUBSTITUTE SHEET

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dispersible and have molecular weights from 5000 to 5,000,000, preferably from 100,000 to 3,000,000. Acrylic acid may be copolymerized with many other comonomers, for example with methacrylic acid, alkyl acrylates or methacrylates, N,Ndialkylacrylamides. Copolymerization with monomers such as ethylene, vinyl acetate, styrene and vinyl chloride is also possible. The amount of comonomer is generally less than 50%, · preferably less than 30%. Some cross-linking may be-present, . especially to modify the molecular weight.

It was known to use gel formulations for pharmaceuticals or cosmetics, but there is practically no risk of pollution or environmental contamination when handling such products, in contrast to pesticides and agrochemicals.

Furthermore, the gels used for pharmaceutical or cosmetic purposes-are generally water-based, so that it was unobvious to obtain gels which are convenient for inclusion in water-soluble sachets or bags and useful for shock absorption purposes in such bags. ·

Furthermore, even when non aqueous liquids are contained in water-soluble bags, the liquids may have a low (i.e., not zero) water content which may cause the bags to break upon freezing. The present invention provides containerisation systems for hazardous compounds e.g. agrochemicals which quickly dissolve when put into water and which are not damaged by normal freezing.

The hereinbefore defined gel may optionally contain an organic solvent or a mixture of organic solvents in which the active ingredient is soluble (eg completely soluble) at room temperature; a dispersant; a secondary thickener such as fumed silica, hydroxyethyl cellulose, carboxymethyl .cellulose,

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-σorganically modified attapulgite or nontnorillonite clay, hardened castor oil, cetyl and stearyl alcohols or esters, polyethylene glycols, glyceryl hydroxystearate, polyvinylalcohols (of low molecular weight) , dioctyl sodium sulfosuccinate and sodium benzoate, alkyl benzene sulfonates, xanthum gum, polyvinylpyrrolidone, polyvinyl acetate, and the like; and other additives such as antifoam agents, stabilizers, buffers, and antifreeze agents. ·

Among the gels used in the present invention, as hereinbefore defined, some particular gels are preferred, especially those comprising 5 to 95%, preferably 10 to 90%, more preferably 25 to 80%, of the active ingredient; 1 to 50%, more preferably 2 to 20%, of the surfactant; 0.1 to 50%, more preferably 0.5 to 5%, of the polyacrylic acid; 0 to 80% of a solvent, more preferably 3 to 50%; 0 to 20% of other additives, preferably 0.1 to 10%; and optionally 1'to 25%, preferably 2 to 8%, of a dispersant. According to a preferred feature of the invention, the components of the compositions are chosen in such a way that one or more of the following feature are typically present:

(i) the resulting gels form a continuous system;

(ii) the resulting gels have a viscosity of 500 to 50,000 centipoises, more preferably of 1000 to 12,000 centipoises;

(iii) the gel has a phase difference phi between the controlled shear stress and the resulting shear strain such that tg(phi) is less than or equal to 1.5, preferably less than or eoual to 1.2;

(iv) the gels preferably have a specific gravity greater than 1, preferably greater than 1.05, more preferably greater than l-l; and/or k

WO 92/01377

PCT/EP91/01351 (v) the gels have a spontaneity (as hereafter defined) of less than 75, preferably less than 25.

The above viscosities are Brookfield viscosities measured with a viscometer in the form of a flat palate rotating at 20 rounds per minute.

Tg(phi) is the tangent of the angle phi (or phase difference). The measurement of phi is made by means of a rheometer having a flat fixed plate and a rotating cone above this plate such that the angle between them is less than 10°, preferably 4®. The cone is caused to rotate by means of a controlled speed motor. The rotation is a sinusoidal one, i.e., the torque and the angular displacement change as a sine function with time. This angular displacement corresponds to the hereabove mentioned shear strain. The torque of the controlled speed motor (which causes the angular displacement) corresponds to the hereabove mentioned controlled shear stress. As used herein, continuous system means a material which is visually homogenous, i.e., which has the visual appearance of having only one physical phase. This does not exclude the possibility of having small solid particles dispersed therein, provided these particles are small enough not to constitute a visible separate physical phase.

It is known that a gel is generally a colloid in which the dispersed phase has combined with the continuous phase to produce a viscous, jelly-like product; it is also a dispersed system consisting typically of a high molecular weight compound or aggregate of small particles in very close association with a liquid.

As used herein, hazardous product means a product which may damage the environment or injure the person handling

SUBSTITUTE SHEET

WO 92/01377

PCT/EP91/01351

-8it. According to one main and preferred feature of the invention, the hazardous product is an active ingredient which is an agrochemical, more precisely a pesticide or a plant protection agent (including plant growth regulators or plant nutrients).

The invention is not limited to specific agrochemicals. A list of the many agrochemicals which can be used in the invention include the following:

fungicides such as Triadimefon, Tebuconazole, Prochloraz, Triforine, Tridemorph, Propiconazole, Pirimacarb, Iprodione, Metalaxyl, Bitertanol, Iprobenfos, Flusilazol,

Fosetyl, Propyzamide, Chlorothalonil, Dichlone, Mancozeb, Anthraquinone, Maneb, Vinclozolin, Fenarimol, Bendiocarb, Captafol, Benalaxyl, Thiram, and the like;

herbicides (or defoliants) such as quizalofop and its derivatives, Acetochlor, Metolachlor, Imazapur and Imazapyr, Glyphosate and Gluphosinate, Butachlor, Acifluorfen, Oxyfluorfen, Butralin, Flauzifop-butyl, Bifenox, Bromoxynil, Ioxynil, Diflufencian, Phenmedipham, Desmedipham, Oxadiazon, Mecopropo, MCPA, MCPB, MCPP, Linuron, Isoproturon, Flamprop and its derivatives, Ethofumesate, Diallate, Carbetamide, Alachlor, Metsulfuron, Chlorsulfuron, Chlorpyralid, 2,4-d-Tribufos, Triclopyr, Diclofop-methyl, Sethoxydim, Pendimethalin, Trifluralin, Ametryn, Chloramben, Amitrole, Asulam, Dicamba, Bentazone, Atrazine, Cyanazine, Thiobencarb, Prometryn, 2-(2chlorobenzyl)-4,4-dimethyl-l,2-oxazolidin-3-one, Fluometuron, Napropamide, Paraquat, Bentazole, Molinate, Propachlor,

Imazaquin, Metribuzin, Tebuthiuron, Oryzalin, and the like;

insecticides or nematicides such as Ebufos,

Carbosulfan, Amitraz, Vamidothion, Ethion, Triazophos, Propoxur,

Phosalone, Permethrin, Cypermethrin, Parathion, Methylparathion,

SUBSTITUTE SHEET

-9Diazinon, Hethomyl, Halathion, Lindane, Fenvalerate, Ethoprophos, Endrin, Endosulfan, Dinethoate, Dieldrin, Dicrotophos, Dichlorprop, Dichlorvos, Azinphos and its derivatives, Aidrin, Cyfluthrin, Deltanethrin, Disulfoton, Chlordimeforn, Chlorpyrifos, Carbaryl, Dicofol, Thiodicarb, Propargite, Demeton, •Phosalone, and the like;

plant growth regulators such as gibberellic acid, ethrel or ethephone, cycocel, Chlormeguat, Ethephone, Mepiquat, and like.

Among the many agrochemicals, the following are of particular interest: the organophosphorous insecticides and hydroxybenzonitrile herbicides such as bromoxynil or ioxynil either in the form of a salt or an ester. ,

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The chemical nature of the enveloping film constituting the bags, which may contain the gel formulation used in the invention, can vary quite widely. Suitable materials are water-soluble or water-dispersible materials which are insoluble in the organic solvents used to dissolve or disperse the agrochemical active ingredient. Specific suitable materials include polyethylene oxide, such as polyethylene glycol; starch and modified starch; alkyl and hydroxyalkylcellulose, such as hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose;

carboxymethylcellulose; polyvinyl ethers such as polymethyvinyl ether or poly(2-nethoxy or ethoxy ethylene); poly(2,4-drmethyl-6triazinylethylene; poly (3-morpholinylethylene); poly (N-1,2,4triazolylethylene) ; poly(vinylsulfonic acid); polyanhydrides; low

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-10moleoular weight urea-formaldehyde resins; low molecular weight melamine-formaldehyde resins; poly(2-hydroxyethyl methacrylate); polyacrylic acid and its homologs. Preferably, the enveloping film comprises or is made from polyvinylalcohol (PVA) . The PVA is generally partially or fully alcoholyzed or hydrolyzed, e.g., 40-100%, preferably 80-99%, alcoholyzed or hydrolyzed polyvinyl acetate film. Preferred materials for the bags are polyethylene oxide, methyl cellulose, or polyvinyl alcohol. When polyvinylalcohol is used, it is advantageously a 40-100%, preferably 80-99%, alcoholyzed or hydrolyzed polyvinyl acetate film.

Preferred materials for the bags are polyethylene oxide, methyl cellulose, polyvinyl alcohol. When polyvinyl alcohol is used, it is advantageously a 40-100%, preferably 8099% alcoholyzed or hydrolyzed polyvinyl acetate film.

Surfactants which are particularly suitable for use in invention are defined by the following test. According to this test, the liquid active ingredient, in the organic solvent if present in the gel, (50g in total) and surface-active adjuvant (i.e., surfactant) (5g) are added to an amount of water, at 50*C, which is sufficient to bring the volume of the mixture to 100 ml. The mixture is agitated sufficiently to form a homogenou' emulsion. The emulsion is allowed to stand for 30 minutes at 50*C in a graduated cylinder. The amount of oily layer which may have separated out (and thus formed a distinct liquid phase) must be less than 20 ml.

In order to assess whether a surface-active adjuvant possesses dispersing properties and may be a ’’dispersant according to the invention, the following test is carried out.

An aqueous suspension (100 ml) containing kaolin or atrazine (SO g), in the form of solid particles having a particle size between ϊ

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WO 92/01377

PCT/EP91/01351 l· f

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I 1 and 10 microns, and the surface-active adjuvant (5cj) is allowed

J to stand at 20^eC for 30 minutes in a graduated cylinder. Kaolin | is used when the dispersing agent is able to disperse a i hydrophilic solid. Atrazine is used when the dispersing agent is f

ί able to disperse a hydrophobic solid. After standing, 9/10ths (nine-tenths) of the volume of the suspension, situated in the upper part of the suspension, is removed, without agitation, and the solids content (residue after evaporation of the water) of the remaining tenth is measured. This solids content must not exceed 12% by weight of the solids content of 100 ml of the suspension on which the test is carried out.

The spontaneity is assessed by the following method. A mixture of 1 ml of gel with 99 ml of water are put into a 150 ml glass tube which is stoppered and inverted through 180°C (i.e., turned upside down). The number of times required to completely disperse the gel is called the spontaneity.

A thickener is a compound which increases the viscosity of a gel or a liquid.

The surfactants which may be used in the invention may be selected from among the following: salts of lignosulfonic acids; salts of phenyl sulphonic or napthaleno sulphonic acids;

ji poly condensates of ethylene oxide with fatty alcohols, fatty i| acids, fatty esters, or fatty amines, or substituted phenols j| u (particularly alkylphenols or arylphenols); salts of i| sulfosuccinic acid esters; taurine derivatives (particularly

Ml alkyltaurates); phosphoric esterc of alcohols or of I polycondensates of ethylene oxide with phenols; esters of fatty

Ο acids with polyols; sulfate, sulphonate and phosphate functional derivatives of the above compounds; and the like.

SUBSTITUTE SHEET r

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- 12 The dispersants which may be used in the invention may be selected from among the following: condensed naphthalene sulfonic acid; polyacrylic acid; sodium sulfosuccinate; calcium lignosulfonate; glyceryl stearate; ethylene glycols; and the like.

The gels used in the invention are generally very easy to make, simply by mixing the components, and most of the time no grinding or milling is necessary. Furthermore, they maintain their rheological properties for a very long time.

In order to make a bag, the film is shaped (and possibly partially sealed) and then filled with the gel. Generally the gels are flowable, even if it is at a slow rate due to their high viscosity. A container which is used to contain the gels cannot be easily emptied due to this high gel viscosity (which is the reason why the gels were not used previously in agriculture). When filled, the bag is finally sealed, generally heat sealed.

Further information may be found in the following copending International patent publications filed on the same day as the present application in the name of the applicants for the present application: WO 92/01374;

WO 92/01375; WO 92/01376; WO 92/01377; and WO 92/01378.

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The following examples are given for illustrative purposes and should not be understood as restricting the invention. In these examples, the tg(phi) is less than 1.5 and the gels are made by mixing the agrochemical, the surfactant and the solvent, adding the polyacrylic acid polymer while stirring at room temperature, and finally adding the water and continuing the stirring for about a half an hour. The mixture is allowed to set overnight.

In the following Examples, unless otherwise stated, all percentages are by weight.

Example 1

The components are 72.6¾ ethoprop, 20¾ xylene, 5¾ polyethoxylated nonyl phenol in fora of the phosphate ester, 1.4¾ polyacrylic acid polymer (1,250,000 molecular weight), and 1 ¾ water. The gel which is obtained has a continuous phase, is clear and transparent, and has a Brookfield viscosity of 11000 centipoises. It thickens upon agitation. The spontaneity is 20 and the density is 1.03.

Exapplg 2

The components are 27.9 ¾ bromoxynil octanoate, 34.1 ¾ bromoxynil heptanoate, 20 ¾ xylene, 14.8 ¾ polyethoxylated nonyl phenol in the fora of the phosphate ester, 1.1 ¾ polyacrylic acid polymer (1,250,000 molecular weight), 1 ¾ of a mixture of dioctylsodium sulfosuccinate and sodium benzoate, and 1.1¾ water.

The gel which is obtained has a continuous phase, is translucent, and has a Brookfield viscosity of 40,000 centipoises. It

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WO 92/01377

PCT/EP91/01351

-14maintains its rheological properties between +50°C and -20^ec.

The spontaneity is 40.

Example..!

The components are 45% ethoprop, 23 % disyston, 20.5% xylene, 5% polyethoxylated nonyl phenol in the form of the phosphate ester, 2% polyacrylic acid polymer (1,250,000 molecular weight), 2% of a mixture of dioctylsodium sulfosuccinate and sodium benzoate, and 1.5% water. The gel which is obtained has a continuous phase and is translucent. The spontaneity is 40.

Example 4

The components are 73.5% ethoprop, 19% xylene, 4.5% polyethoxylated nonyl phenol in the form of the phosphate ester, 2% polyacrylic acid copolymer (1,250,000 molecular weights), and 1% water. The gel which is obtained has a continuous phase and is clear and transparent. The spontaneity is 30. It is stable for 5 months at -20*C.

Example 5 .

The components are 27.9% of bromoxynil octanoate,

34.1 % bromoxynil heptanoate, 22.6% xylene, 13 % polyethoxylated nonyl phenol in the form of the phosphate ester, 0.9% polyacrylic acid polymer (1,250,000 molecular weight), 0.5% of alkyl benzene sulfonate, and 1% water. The gel which is obtained has a continuous phase, is translucent, and has a Brookfield viscosity of 5000 centipoises. It maintains its rheological properties between +50°C and -20°C. The spontaneity is 20. It is stable for 3 months at -20*C.

Example 6

The components are 31.5% bromoxynil octanoate, 31.5% bromoxynil heptanoate, 21.2 % xylene, 13% polyethoxylated nonyl phenol in the form of the phosphate ester, 0.9% polyacrylic acid

SUBSTITUTE SHEET

WO 92/01377

PCT/EP91/01351

-15polymer (1,250,000 molecular weight) , 0.9 t of a mixture of dioctylsodium sulfosuccinate and sodium benzoate, and 1 % water. The gel which is obtained has a continuous phase, is translucent, has a Brookfield viscosity of 3000 centipoises

Example 7

The components are 33% of bromoxynil octanoate, 33% bromoxynil heptanoate, 21.6% xylene, 11 % of the sodium salt of polyethoxylated nonyl phenol in the form of the phosphate ester (this salt contains 10 % water and thus it is added as the last component during the mixing), and 1.4% polyacrylic acid polymer (1,250,000 molecular weight). The gel which is obtained has a continuous phase and is translucent.

Example 8

The gels according to the examples 1 to 7 are used in the following way. A total of 1100 g of the gel is put in a 1 liter bag made of a film of PVA (88% hydrolyzed polyvinyl acetate which is cold water-soluble and has a thickness of 55 microns).

The bag, which is almost full (about 95% v/v), is heat sealed. The bag is then dropped 10 times upon the ground from a height of 1.2 m. No breaking or leakage is observed.

The bag is put in a tank containing water under gentle agitation (that is to say such as that obtained with pump recycling). It is w«ll dispersed within a short time. There is no clogging in the filter which is a 100 mesh screen.