AU740483C

AU740483C - A method of dispersing an insoluble material in an aqueous solution and an agricultural formulation

Info

Publication number: AU740483C
Application number: AU95244/98A
Authority: AU
Inventors: Andrew Francis Kirby; Rodney Walter Parr; David Hayshiv Parris; Phillip Robert Tudor
Original assignee: Huntsman Surfactants Technology Corp
Current assignee: Huntsman Surfactants Technology Corp
Priority date: 1997-10-14
Filing date: 1998-10-14
Publication date: 2003-07-03
Anticipated expiration: 2018-10-14
Also published as: AU9524498A; AU740483B2

Description

A Method of Dispersing an Insoluble Material in an Aqueous solution and an Agricultural Formulation.

The present invention relates generally to dispersants, for use in agricultural applications, in

particular the present invention relates to methods for the dispersion of insoluble material with copolymeric dispersants which dispersions are formed with improved dispersibility and show

improved suspensibility. The present invention also relates to methods of producing

dispersible formulations, the formulations per se and methods of treating substrates with dispersions produced from such formulations.

The active principles in many agricultural applications are largely hydrophobic or water

insoluble in character and are, by necessity, often administered as finely divided solids

suspended in aqueous media. The majority of these active principles are manufactured and marketed in concentrated form, possibly with the addition of other insoluble inert fillers,

which are then diluted prior to application. For example, the active principle is typically

available in the form of a suspension concentrate (SC), wettable powder (WP) or water

dispersible granule (WG). However, due to the generally hydrophobic nature of the active

principle, the addition of a suitable dispersant is essential in order to achieve an homogenous

dispersion with a minimum of mixing, such as may be achieved readily by hand or with

minimal mechanical mixing. Furthermore, once an homogenous dispersion is achieved, the

resulting suspension must remain stable for a time sufficient, at least, to allow application by

usual means such as spraying. Any settling, agglomeration or flocculation of the finely

divided solid may lead to inconsistent and ineffective application as well as blockage of the spraying equipment. It is therefore necessary to provide a dispersant which provides easy and homogenous dispersion and results in a suspension which maintains its stability during the

application of the aqueous dispersion.

Effective dispersants for use in these applications ideally provide a suspension with

acceptable dispersibility, suspensibility and lack of agglomeration. The Collaborative

International Pesticides Analytical Council (CIPAC Handbook Volume 1) defines methods

that can be used for determining acceptable suspensibility (MT 15J) and degree of agglomeration (MT 59.3). For example, in suspension concentrates so-called SC

formulations, this can be achieved by the addition of about 3-5 w/w% of a standard

dispersant. Wettable powder (WP) and water dispersible granule (WG) formulations

generally require the addition of standard dispersant in the order of 6-7 w/w% in order to

achieve acceptable suspensibility and degree of agglomeration as determined by a wet sieve

retention test. (MT 59.3).

Currently used dispersants for SC formulations include ethylene oxide/propylene oxide block

copolymer surfactants based on an hydrophobic moiety plus ethyleneoxide. Also used are

ether phosphate derivatives of non-ionic surfactants, especially of tristyrylphenol ethoxylates.

Conventional anionic surfactants used include sulphonated derivatives of arylformaldehyde condensates, polyacrylates and lignosulfonates.

Dispersants for WP and WG formulations are usually limited by the requirement that the dispersant be solid at ambient temperatures, be non-gelling and not dissolve the active principle. For these reasons, conventional non-ionic surfactants are often unsuitable, and

anionic dispersants are preferred. Known effective dispersants for WP and WG formulations

include sulphonated alkylnaphthalene/formaldehyde condensate salts and lignosulfonate salts.

oj-Olefin-polycarboxylate copolymers are well known as dispersants in a wide range of

applications including pigment dispersion, emulsion polymerisation, cosmetics and pesticidal

compositions. As far back as 1972 the sodium salt of a maleic anhydride and diisobutylene

copolymer was given an exemption from tolerance for use in pesticide formulations by the

United States Environmental Protection Authority following a petition from Rohm and Haas Co. FR 2545325 describes the use of ammonium and alkali metal salts of maleic anhydride-

diisobutylene copolymer in pesticide granules. Similarly, EP 201417 describes the use of

copolymers of maleic anhydride with surfactants selected from sulfates and phosphates of

ethoxylated phenol derivatives in WP and WG formulations. JP 62036302 describes

copolymers having a molecular weight range of from 5000-20000 for use with granular

agrochemical compositions. Maleic anhydride and diisobutylene copolymer derivatives are

described for use in conjunction with CaCO₃ and Mg salts for SC formulations in JP 06

09,302. The use of sulfonated derivatives of copolymers of maleic anhydride in water

dispersable granules is also described in JP 58-131903.

French Patent No. 2,397,444 describes stable and concentrated dispersions of active materials which may be prepared from non-dusting powders or granular materials. It is necessary to separate the active material in the presence of a salt of an acidic resin, such as, for example,

a copolymer of maleic anhydride and an -olefinic compound; add an organic solvent which

forms, together with the aqueous medium, a two-phase system; treat such two-phase system

by adding a carrier substance thereto; and then isolate the product by a reduction in the volume of the organic phase by the addition of water, the solvent gradually transferring into

the added water.

We have now found that the use of certain of a range of derivatised copolymers comprising

olefin monomers and α,β-unsaturated oxyacid monomers surprisingly provides improvements

in dispersibility of WG formulations and suspensibility of dispersed agricultural active ingredients when compared to use of the parent copolymer. The improvement is also found

surprisingly not only in alternating copolymers but in a range of other copolymers including random and block copolymers.

We have found that agriculturally acceptable salts or other water soluble derivatives of

alternating copolymers for use as dispersants in agricultural compositions provide improved

and consistent dispersant performance when compared to conventionally used dispersants such

as sulphonated alkylnaphthalene formaldehyde condensate salts. However, we have found

further derivatisation not only of these copolymers but of non-alternating copolymers

provides even greater improvement.

Methods for making such copolymers and derivatizations herein described will be well known to those skilled in the art of polymer synthesis.

According to a first aspect of the present invention, there is provided a method of dispersing

an insoluble material in an aqueous solution comprising the following steps:

(i) providing a formulation comprising at least one insoluble material and at least one

dispersant comprising a copolymer wherein said copolymer comprises a residue of a

first comonomer and a residue of a second comonomer, wherein said first comonomer

is an α,β-unsaturated oxyacid or anhydride and said second comonomer is an olefin

having at least one polymerizable double bond and wherein at least one of said first

comonomer and said second comonomer is substituted, wherein the substituents for

said first comonomer are selected from the group consisting of esters, amides,

thioesters and functional groups derived from reaction with nucleophilic reagents and wherein the substituents for the second comonomer are selected from the group

consisting of epoxides; sulfonates; esters; amides; and optionally substituted pendent

aromatic and heteroaromatic groups wherein said optional substituents are selected

from the group consisting of sulfonates, nitrates, phosphates and other substituents derived from reaction with electrophilic reagents.

(ii) dispersing said formulation in an aqueous medium.

According to a second aspect of the present invention, there is provided a method of making an agrochemical formulation comprising the steps of:

(i) combining at least one insoluble material, and at least one dispersant comprising a

copolymer wherein said copolymer comprises a residue of a first comonomer and a

residue of a second comonomer, wherein said first comonomer is an ,β-unsaturated

oxyacid or anhydride and said second comonomer is an olefin having at least one

polymerizable double bond and wherein at least one of said first comonomer and said

second comonomer is substituted, wherein the substituents for said first comonomer

are selected from the group consisting of esters, amides, thioesters and functional

groups derived from reaction with nucleophilic reagents and wherein the substituents

for the second comonomer are selected from the group consisting of epoxides;

sulfonates; esters; amides; and optionally substituted pendent aromatic and

heteroaromatic groups wherein said optional substituents are selected from the group

consisting of sulfonates, nitrates, phosphates and other substituents derived from

reaction with electrophilic reagents;

(ii) milling said combination to a particle size range in order to obtain a stable, readily - suspendible aqueous dispersion; and

(iii) stabilising said aqueous dispersion to obtain an SC formulation suitable for dilution

in water for agricultural use. According to a third aspect of the present invention, there is provided a method of making

an agrochemical formulation comprising the steps of:

(i) combining at least one insoluble material, with at least one dispersant comprising a

copolymer wherein said copolymer comprises a residue of a first comonomer and a

oxyacid or anhydride and said second comonomer is an olefin having at least one

for the second comonomer are selected from the group consisting of epoxides;

sulfonates; esters; amides; and optionally substituted pendent aromatic and

reaction with electrophilic reagents; and

(ii) milling said combination to a desired particle size to obtain a homogeneous wettable

powder (WP) formulation.

According to a fourth aspect of the present invention, there is provided a method of making

an agrochemical formulation comprising the steps of: (i) combining at least one insoluble material suitable for agricultural use with at least one

said first comonomer are selected from the group consisting of esters, amides,

thioesters and functional groups derived from reaction with nucleophilic reagents and

wherein the substituents for the second comonomer are selected from the group

aromatic and heteroaromatic groups wherein said optional substituents are selected from the group consisting of sulfonates, nitrates, phosphates and other substituents

derived from reaction with electrophilic reagents; and

(ii) blending said combination to obtain a homogeneous wettable powder (WP)

formulation.

According to a fifth aspect of the present invention, there is provided a method of making an

agrochemical formulation comprising the steps of:

(i) combining at least one insoluble material suitable for agricultural use with at least one dispersant comprising a copolymer wherein said copolymer comprises a residue of a first comonomer and a residue of a second comonomer, wherein said first comonomer is an α,β-unsaturated oxyacid or anhydride and said second comonomer is an olefin

having at least one polymerizable double bond and wherein at least one of said first comonomer and said second comonomer is substituted, wherein the substituents for

said first comonomer are selected from the group consisting of esters, amides,

wherein the substituents for the second comonomer are selected from the group

from the group consisting of sulfonates, nitrates, phosphates and other substituents

derived from reaction with electrophilic reagents;

(ii) agglomerating said combination to form discrete granular materials; and

(iii) drying said granular materials to obtain a water dispersible granule WG formulation.

According to a sixth aspect of the present invention, there is provided a formulation produced by the process of the second, third, fourth and fifth aspects.

According to a seventh aspect of the present invention, there is provided an agricultural formulation comprising at least one insoluble material and at least one dispersant comprising a copolymer wherein said copolymer comprises a residue of a first comonomer and a residue of a second comonomer, wherein said first comonomer is an ,β-unsaturated oxyacid or

anhydride and said second comonomer is an olefin having at least one polymerizable double

bond and wherein at least one of said first comonomer and said second comonomer is

substituted, wherein the substituents for said first comonomer are selected from the group

consisting of esters, amides, thioesters and functional groups derived from reaction with

nucleophilic reagents and wherein the substituents for the second comonomer are selected

from the group consisting of epoxides; sulfonates; esters; amides; and optionally substituted

pendent aromatic and heteroaromatic groups wherein said optional substituents are selected

from the group consisting of sulfonates, nitrates, phosphates and other substituents derived

from reaction with electrophilic reagents.

According to an eighth aspect of the present invention, there is provided a method of

treatment of a substrate with an insoluble material comprising the following steps:

(i) preparing a formulation comprising at least one insoluble material and at least one

first comonomer and a residue of a second comonomer, wherein said first comonomer is an ,β-unsaturated oxyacid or anhydride and said second comonomer is an olefin

said first comonomer are selected from the group consisting of esters, amides,

derived from reaction with electrophilic reagents;

(ii) dispersing said formulation in an aqueous medium; and

(iii) applying the dispersed formulation to a substrate.

The derivitisation of the copolymer is of central importance to the invention herein described.

While not wishing to be bound by theory, it appears that in addition to the enhanced

solubility in water, it may confer additional polarity or charge density to the dispersant such

as to enhance its performance. Further it may lead to better conformational alignment of the

copolymer and therefore the copolymer is more readily soluble and may more readily align

itself with surfaces. We have found that a non alternating polymer which is unsuitable for use as a dispersant when used as an alkali metal or quaternary ammonium salt derivative is

significantly improved in dispersant performance when derivatised according to the present invention.

The first comonomer for use in the present invention may be any comonomer polymerizable

with the second comonomer. Examples of suitable preferred first comonomers of the present invention include fumaric acid, maleic acid and anhydrides, and the esters, amides and imides

derived from them, itaconic acid and anhydride and the corresponding esters amides and

imides derived from them, acrylic and methacrylic acids, esters and amides, vinylphosphonic

acid and the corresponding esters and amides derived from it and ethylene sulphonic acid and

the esters and amides derived from it.

The second comonomer for use in the present invention is an olefin having at least one

polymerizable double bond which may be substituted as defined herein.

The second comonomer for use in the second embodiment of the present invention may be

an alicyclic monomer having a polymerizable exo-cyclic double bond. It will be understood

that by alicyclic monomer is meant an aliphatic cyclic monomer containing moieties such as

a cyclic alkyl, cyclic alkenyl or heterocyclic groups and which may comprise one or more

carbocyclic or heterocyclic rings. It will be understood that by exo-cyclic is meant an

alkylidene substituted cyclic structure. Alicyclic monomers having a polymerizable exo-

cyclic double bond may optionally be substituted. Alicyclic monomers having a

polymerizable exo-cyclic double bond of the present invention may include, for example, β-

pinene, 5-ethylidene-2-norbornene, methylene cyclohexane and methylene cyclopentane. The most preferred alicyclic monomer having a polymerizable exo-cyclic double bond.

an alicyclic monomer having a polymerizable endo-cyclic double bond. The term alicyclic monomer is as hereinabove defined. It will be understood that by endo-cyclic is meant the

polymerizable double bond has both ends (or termini) forming part of the cyclic structure of

the alicyclic monomer. Alicyclic monomers having a polymerizable endo-cyclic double bond

may optionally be substituted. Alicyclic monomers having a polymerizable endocyclic

double bond may include substituted and unsubstituted norbornene, cyclopentadiene and

substituted cyclopentadienes, substituted and unsubstituted dicyclopentadienes , cyclohexenes,

furans and indenes. Most preferred of the above monomers containing an endo-cyclic double

bond are dicyclopentadiene and dimethyldicyclopentadiene.

an α-olefin having at least one cyclic substituent. It will be understood that by -olefin is

meant an olefinic compound having a terminal double bond. Suitable cyclic substituents

include benzene and substituted benzene, cyclopentane, cyclohexane, and other

cycloaliphatics, heterocyclics, heteroaromatics, aromatics and polyaromatics. Examples of

suitable α-olefinic cyclic compounds include limonene and similar terpenes, vinyl

cyclohexanes, vinyl cyclohexenes, vinyl pyridines, vinyl thiophenes, vinyl naphthalenes, vinyl furans, vinyl pyrans and, vinyl pyrrolidones. Most preferred α-olefin cyclic monomers

include limonene, vinyl naphthalene, vinyl pyrrolidone, allyl glycidyl ether and vinyl

cyclohexene.

The second comonomer of the second embodiment of the present invention may be an α- olefin having an alkyl group such as diisobutylene, isobutylene, n-octene, n-decene, allyglycidylether of vinylisobutylether. The second comonomer may also be an internal

olefin.

Preferred examples of the first comonomer may be described as having structure I

0

II

R,

I

wherein R, is M a metal, quaternary ammonium, phosphonium or sulphonium residue, R₂

is hydrogen or C, to C₄ alkyl is a carbon atom, Y is a carbon O=S, or POR_x a hydrogen atom

or alkyl radical having from 1 to 10 carbon atoms (or carboxylated such radical) and R, is H,

an alkyl radical or a carboxylic acid derivative of form II

O II c R<

II

wherein R₅ is OR^, NR^ , SR_β, wherein Rg ,R₇ , are H, alkyl, O-alkyl, or alkyl groups with a hetero atom substituent. The

second comonomer may be alternatively described as a residue having formula III

CH. C

Re

III

wherein R₈ represents hydrogen, a straight or branched chain alkyl of from 1-4 carbon atoms,

Rg represents hydrogen, a branched chain alkylradical from 1-12 carbon atoms, or cycloalkyl

radical,

and/or a vinyl compound of formula IV

-^R10

CH, C

R 11

IV wherein R₁₀ is a straight or branched chain alkyl radical of from 1-4 carbons and R_n is given

by formula V, VI or VII,

VI VII

wherein R₁₂ represents one or more alkyl radicals or one or more of H,Cl,OR and SO₃R,

NO₂, PO₃R, and X is a hetero atom other than carbon; and/or an olefin shown by formula

VIII,

VIII

wherein R₁₃ is Cl, or SO₃R, , alkyl, O-alkyl, O-aryl and R₁₄, represents from 4-20 carbon atoms such as to make H a cyclic or polycyclic alkane or polyalkenyl compound, R₁₅ , is an

epoxide or SO₃R, reacted with an unsaturated portion of the ring comprising R₁₄;

and/or an exocyclic olefin shown by formula IX

IX

and/or an internal olefin shown by formula X,

where R₉ is the same or different and as hereinabove defined.

The dispersant copolymers of the present invention may also include copolymers being the

water soluble derivatives of a combination of an unsaturated α,β -unsaturated oxyacid or

anhydride and another olefmic monomer, not limited to being of -an alternating structure, that

may have been derivatised post copolymerisation such as to provide the necessary substituents

which may enhance water solubility and regularity of charge or polarity on the polymer.

Such derivatisation includes that obtained from reaction of groups pendant to the copolymer

such as acids and acid derivatives with nucleophilic reagents such as alcohols, amines and

thiols to give esters, amides and thioesters respectively.

In a further form of derivatisation copolymers with residual reactive unsaturation may be

reacted with electrophilic or radical reagents such as peroxides or sulphite to give epoxides

and sulphonates respectively.

In a special case of the above, copolymers with pendant aryl or heteroaryl groups can be

made to undergo electrophilic aromatic substitution with sulphonating, nitrating and phosphating reagents.

While not wishing to be bound by theory, copolymers with hydroxyl groups can be esterified with acids including carboxylic, sulphuric and phosphoric acids. The alternating, or

repeating, units are preferably monomers but may also be dimers, trimers or small oligomers.

While not wishing to be bound by theory, it is believed that the stiffness of the polymer

molecule is relates to its performance as a dispersant. It is believed that improved dispersant

performance is related to the degree of steric hindrance and the resistance of copolymer to

free rotation.

The copolymer may contain additional comonomer residues. For example, the addition of

a small amount, say less than 10% , of methyl methacrylate will not substantially change the

character of the derivatised copolymer. The copolymer may contain residues of additional

olefin comonomers whether derivatised or not. Suitable copolymers for use in the present

invention also include copolymers of three or more comonomers. Additional comonomers

may also be incoφorated into the derivatised copolymer without changing the character of

the polymer.

While not wishing to be bound by theory it appears that where a consistent hydrophobic

polymer backbone is provided in the presence of regularly spaced anionic charge or steric

barrier along the polymer, the improved dispersant performance is preserved.

The preferred molecular weights of the copolymers of the present invention are in the range

of from 1000 to 90000 daltons. We have found that certain higher molecular weight copolymers show a certain degree of intractability in solution and our more preferred range is from 1000-30000 daltons, even more preferred is 1000-10000 daltons.

We have found that agriculturally acceptable salts of copolymers as described herein for use

as dispersants in agricultural compositions provide improved and consistent dispersant

performance when compared to conventionally used dispersants such as sulfonated

alkylnaphthalene formaldehyde condensate salts.

It is suφrising that copolymers as described herein give enhanced performance when

compared to previously described dispersants structures in the prior art such as for example

diisobutylene, isobutylene and styrene copolymers with maleic anhydride while still other

derivatives described in those same publications, cannot be reasonably used as dispersants in

agricultural applications at all. For example we have found that styrene-maleic anhydride

copolymer derivatives resulted in a less stable and sometimes unstable dispersion. Further,

copolymers of methylvinylether and maleic anhydride also afford an unstable dispersion.

Similarly some linear α-olefin maleic anhydride derivatives such as those derived from n-

octene and n-decene also yielded unstable dispersions affording poor suspensibility. It was

found that the substituted or derivatised copolymers of the above copolymers according to the

present invention showed improved performance not limited by possible effects of molecular

weight and/or molecular conformation which appear to limit the performance of the parent copolymer. The performance of the copolymers described herein has been observed at different dispersant

concentrations in WP and WG formulations to exhibit improved storage stability. Also we have found that in many cases it is possible to lower the dispersant concentration from

normally accepted levels and retain an acceptable suspensibility result, thereby achieving

more efficient the surface coverage of the dispersant. In practical terms this means the

dispersant will be more cost effective to the end user. When the use rate of copolymers is

compared to that of a diisobutylene maleic anhydride sodium salt of similar molecular weight typically we have found that the copolymers of this invention may give acceptable stability

at a concentration lower than the corresponding diisobutylene derivative. In addition the

formulations typically show improved dispersibility. When compared to sulfonated alkyl

naphthalene formaldehyde condensates, suspensibility is significantly improved, even at lower

concentrations.

Methods for making such copolymers of the second embodiment of the present invention

from first and second comonomers will be well known to those skilled in the art of polymer

synthesis. The comonomers of the present invention may be substituted prior to or post

polymerization with methods which will be appreciated by those skilled in the art.

The dispersant system used in embodiments of the present invention may be a mixture of the

copolymer as herein described with other dispersants known to those skilled in the art, including alkyl substituted and unsubstituted sulfonated naphthalene formaldehyde condensate

salts, alkyl substituted and unsubstituted phenol formaldehyde condensate salts, lignosulphonate salts, polyacrylate salts, and previously described α-olefinic unsaturated

dicarboxylic acid copolymer derivatives.

In agrochemical applications, a wide variety of insoluble materials such as active principals are delivered in aqueous suspension. Active principals such as those used in WP, WG and

SC formulations are generally insoluble at ambient temperatures. Water insoluble materials

which may advantageously be used in WP, WG and SC formulations include herbicides,

insecticides, fungicides, biocides, molluscicides, algaicides, plant growth regulators,

anthelmintics, rodenticides, nematocides, acaricides, amoebicides, protozoacides, crop safeners and adjuvants. Examples of such actives commonly granulated or made as powders

in agriculture include: triazine herbicides such as simazine, atrazine, terbuthylazine,

terbutryn, prometryn and ametryn, urea herbicides such as diuron and fluometron, sulphonyl

urea herbicides such as chlorsulfuron, metsulfuron methyl, nicosulfuron and triasulfuron,

sulphonanilide herbicides such as flumetsulam, organophosphate insecticides such as azinphos

methyl, chloφyrifos, sulprofos and azamethiphos, carbamate insecticides such as aldicarb,

bendiocarb, carbaryl and BPMC, synthetic pyrethroids such as bifenthrin, as well as various

types of fungicides including dimethomoφh, benomyl, carbendazim, mancozeb, triazoles

such as hexaconazole and diniconazole, acaricides such as propargite. A list of such products

can be drawn from the Pesticide Dictionary (contained in the Farm Chemicals Handbook) or

the British Crop Protection Society: Pesticides Manual.

In addition, some fertilizers and also water soluble active principles may use water dispersible formulations either by addition of inert carriers for convenience in handling or to aid in a

controlled release formulation.

A wide variety of other insoluble materials are used in agricultural applications including

fillers and carriers, for example but not limited to, natural and synthetic silicates and silicate

minerals, mineral oxides and hydroxides and also natural and synthetically derived organic

materials. Such materials may be added as porous carriers, as moisture inhibition agents,

to aid binding or agglomeration properties of a formulation or simply to fill a formulation to

a convenient weight. Examples of such fillers may include natural silicates such as

diatomacious earth, synthetic precipitated silicas, clays such as kaolin, attapulgites and

bentonites, zeolites, titanium dioxide, iron oxides and hydroxides, aluminium oxides and

hydroxides, or organic materials such as bagasse, charcoal, or synthetic organic polymers.

These other insoluble materials may be readily dispersed in accordance with the present

invention.

An additional agent conventionally used in combination with dispersants used in the above

formulations is a surfactant wetting agent. The role of the wetting agent in the case of SC

formulations is to aid removal of air from particle surfaces during manufacture and to aid

dilution in water. In the case of WP formulations the role of the wetter may be to aid

penetration of the solids into water, while in the case of WG formulations it may aid penetration of the granules into water and aid disintegration of granules back to primary particle size. In some cases the dispersant may itself function as a suitable wetting agent while in others the dispersant may show an antagonistic effect on the wetter. As a further

embodiment of the present invention at least one surfactant wetting agent may be selected

from the group consisting of an alkylpolysaccharide; di or mono alkyl sulphosuccinate

derivative; a nonionic surfactant loaded onto an inert silicate carrier; and a non-ionic

surfactant delivered in the form of a urea surfactant complex.

The step of dispersing the formulation in an aqueous medium may be achieved by any

convenient means dependent on the nature of the formulation. It is desirable that the

dispersion of the formulation in an aqueous solution may be conducted either by hand or with

a minimum of mechanical agitation. Mechanical agitation may include stirring, mixing,

blending and other similar processes.

The suspension of insoluble material in aqueous medium will be typically used for the

treatment of a substrate such as plant or other agricultural medium. The application of the

suspension onto the substrate may be achieved by any convenient means, including spraying,

and the like. Granules are generally dispersed in water prior to being sprayed by the farmer.

Farm sprays may be as a small back-pack handspray or a large boom spray or other

convenient means. Aerial spraying is also sometimes used.

Formulations of the present invention may also be applied to the substrate directly, prior to

dispersion. The subsequent application of rain or other aqueous media is sufficient for the

formulation of the suspension of particulate material. The present invention is described with reference to WP, WG and SC formulations. In each case, formulations provide a stable aqueous dispersion of finely milled insoluble hydrophobic

particles. The stability properties of the dispersion and hence the effectiveness of the

dispersion can be measured by means of a suspensibility test as described by the CIPAC test MT 15 J . In this test the volume fraction of suspended material is compared to that which

has settled out due to gravity after 30 minutes. Typically a reported percentage suspersiblity

about 80% would be considered as an effective dispersant for WG and WP formulations, while in excess of 90% would be expected for an SC formulation. Another measure of the

stability of the dispersion is the degree to which particles remain non aggregated. This may

also be a property of the even distribution of the dispersant in the formulation. The degree

to which particles may be aggregated is often measured by a wet sieve retention test as

described in CIPAC test MT 59.3. In this test the dispersed solid is poured through a series

of fine sieves and retained material is measured as a fraction of the total amount of dispersed

material. Formation of such aggregates is a major problem observed in WG formulations and to a lesser extent in WP formulations.

Generally WP formulations are produced by milling the active principle either alone or in

combination with fillers, dispersants and/or surfactant wetters to a suitable particle size,

typically in the 5-15 μm range. The milled material is then dry blended with a surfactant

wetter, and/or dispersant if not already present or with additional dispersants and/or surfactant

wetters to give a homogeneous composition. The powder formulation is assessed for

wettability according to a method such as CIPAC MT 53.5 J and suspensibility as per CIPAC MT 15 J . A formulation will desirably have a wettability of less than 1 minute and a

suspensibility above 80%. Below 60% would generally be considered unacceptable. Results

which might be commercially acceptable are either determined by the local registration

authority or by the standards set by the formulators themselves.

In the case of WG formulations a suitably milled active ingredient with or without other

fillers, typically of particle size 5 to 15μm, may be mixed with one or more surfactant wetters

and one or more dispersants. Typically an excess of water is added to bind the particles

together into agglomerates. The excess water is later reduced by suitable air drying

techniques to an optimal level.

The agglomerates are typically granulated using one of many techniques including pan

granulation, drum granulation, fluid bed granulation, spray drying, tableting or extrusion

techniques which are well known to those skilled in the art.

The wetter and dispersant may either be powder blended with the active ingredient or

alternatively blended as an aqueous solution in the water used to aid agglomeration. The

active ingredient, fillers, wetter and dispersant may also be milled together in one operation

prior to addition of water.

For a WG formulation to be acceptable an additional requirement is that the said granules

should readily disperse in water back to the primary dispersed particle size within a short period. This property is known as dispersibility and in describing the current invention it is

measured as the time taken for granules to disperse back to primary particle size in water

under a standard degree of agitation. A dispersion time of less than one minute is desirable,

20 seconds is excellent and 2 minutes is poor. Desirably the granules should also have good

suspensibility. Suspensibility is typically tested using CIPAC MT 15J. Above 80% is a

desirable result, less than 60% is generally regarded as undesirable. In many cases when

testing granules a so-called maximum surface coverage result is often obtained. This is where

the suspensibility results reach a maximum level then plateau. Adding more dispersant will not generally improve the result. This phenomenon is thought to be due to the particle size

distribution of the material. Usually there is a given number of particles which are of such

a size that they will settle regardless of type and concentration of dispersant.

Desirably the granules should have low wet sieve retention. Wet sieve retention is typically

tested using CIPAC MT 59.3. For the 150 μm sieve less than 0.1 % retained material is

desirable. Less than 0.02% is more desirable. Likewise for the 53 μm sieve less than 0.6%

is desirable, anything less than this is more desirable.

A further desirable property of a WG formulation is that the granules should be non-dusty and

resistant to attrition. This is often a property of the method of granulation used and the level

of compaction there obtained. Often there is an observed tradeoff between the dispersibility properties of a WG formulation and the level of compaction and attrition resistance. Attrition

resistance may be measured by subjecting granules to a set degree of agitation and measuring the level of smaller particles generated by means of passing through sieves of various sizes.

Storage stability may be tested by storage at 50 degrees Celsius and tested as above at 1 month

and 3 month intervals to determine if any properties have changed significantly.

Preferably, the granules should maintain these properties on storage. Suφrisingly, it has

been observed that, upon prolonged storage, solid formulations such as WP and WG

formulations containing dispersants such as those described herein are not as susceptible to

deterioration in dispersability and suspensibility as formulations of the prior art.

We have also found that WP and WG formulations which incoφorate the dispersants

described herein require typically less dispersant, than for presently known WP and WG

formulations.

As a further embodiment of the present invention in the case of WP and WG formulations the

dispersants herein described may be combined with surfactant wetting agents selected from

the classes comprising alkylpolysaccharides, dialkyl and monoalkylsulphosuccinate salts,

nonionic surfactants loaded onto porous silicate carriers and urea surfactant complexes of non-

ionic surfactants. The wetting agent may be combined in .such formulations at a rate in excess

of 1 % w/w and preferably less than 3% w/w. Most preferred from the alkylpolysaccharide class of wetting agents are alkylpolyglucosides derived from reaction with glucose and a primary hydrocarbon alcohol. Even more preferred are the highly crystalline derivatives such as obtained from ECOTERIC AS 20 and ECOTERIC AS 10 (Orica Australia Pty Ltd). Most preferred from the monoalkylsulphosuccinate class are sodium or potassium salts of

cyclohexyl, iso-octyl and n-octyl sulphosuccinate. Most preferred from the dialkylsulphosuccinate class are sodium or potassium salts of dicyclohexyl, diisooctyl and di-

n-octyl sulphosuccinates. Most preferred from the class of nonionic surfactants loaded onto

insoluble porous silicate carriers are ethoxylated surfactants loaded onto carriers such as

TERIC 157 (Orica Australia Pty Ltd). Most preferred wetting agents from the urea surfactant

complexes are urea adducts of alcohol ethoxylate surfactants such as TERWET 7050 (Orica

Australia Pty Ltd). The wetters herein described show good wettability and dispersibility for

the formulations and have the additional advantage of showing storage stability in

combination with the copolymer dispersants described. Whereas by comparison some

commonly used WG and WP wetters such as alkylnaphthalene sulphonate salts and

lignosulphonate salts have been found to show poor storage stability.

In the case of SC formulations in the present invention an active ingredient is typically added

to water containing a dispersant, preferably with a surfactant wetting agent together with a

conventional non-ionic dispersant. A humectant may also be included. A dispersion is

formed using high shear mixing. The dispersion is then milled by any one of several means

of wet milling so that the mean particle size of the dispersed solid is below 5 μm more

typically in the range of from 1 to 3μm. The resulting product is known as a millbase and

may be modified with additives such as antifreeze, thickeners and antisettling agents, biocides and colouring agents may be added. For an SC formulation to be acceptable it should not show a high degree of thickening, settling or growth of aggregates over time. These physical

properties can be assessed by visual observation.

SC's generally require good viscosity and storage stability. Storage stability is usually

assessed as degree of top settling or syneresis, sedimenting or "claying" which is the tendency to form a sticky layer on the bottom and "bleeding" which is the tendency of the dispersion

to separate without necessarily displaying even settling. Redispersibility is also important.

These may also be assessed visually.

For SC formulations in the case of dispersants described herein only certain dispersant

copolymers are suitable. When used alone, some dispersant copolymer derivatives give a

viscosity of slurry premix unsuitable for milling so it is preferable to combine the dispersant

with another fast acting well known dispersant such as an EO/PO block co-polymer type

dispersant. While not wishing to be bound by theory it appears that the dispersant needs time

to migrate to the surface of the dispersed particles. The dispersant copolymers are used

synergistically with other known dispersants in some cases.

While the present invention has been described with reference to agrochemical formulations,

it will be apparent that the improvements in dispersibility and suspensibility will render the

present invention useful in other applications. The present invention will now be further

described with reference to the following non-limiting examples and figures. All percentages

recited herein are by weight of the total composition unless otherwise specified. Example 1.

A Simazine 900g/kg WG formulation of the following composition was prepared.

Simazine tech. (98% w/w) 91.8 % w/w

MORWET EFW 1.5 (Witco Coφ.)

DISPERSANT 6.2

Water 0.5%

The dispersant used was an alkylnaphthalene formaldehyde condensate salt, SCS 2258 (ICI

Surfactants). The granules were prepared by blending the solids with approximately 15 % by

weight of water such as to give a plastic premix which was then extruded using a Fuji-Paudal

laboratory scale extrusion granulator. The resulting granules were then dried by means of a

fluid bed drier back to a water content of approximately 0.5% w/w.

The resulting WG was tested for dispersibility by recording the time in seconds required for

total disintegration under uniform agitation. The suspensibility was tested according to

CIPAC MT 15 J and the wet sieve retention was tested using 150 micron and 53 micron sieves according to CIPAC MT 59.3. Results are recorded in TABLE 1.

Example 2

A simazine 900 g/Kg WG was prepared and tested as described in example 1 where the

dispersant used was POLYFON H (Westvaco Coφ), a lignosulphonate salt. The results are described in TABLE 1. Example 3.

A Simazine 900g/kg WG formulation of the following composition was prepared :

Simazine tech. (98% w/w) 91.8 % w/w

ATPLUS G73050 1.5 (now sold under the trademark TERWET 7050, Orica Australia Pty Ltd)

DISPERSANT 3.1

Kaolin 3J

Water 0.5%

The dispersant used was the sodium salt of an alternating copolymer of n-octene and maleic

anhydride of approximate molecular weight 20,000 to 30,000. The granules were prepared

and tested in the manner described in Example 1. The results are shown in TABLE 1.

Example 4.

A Simazine 900g/kg WG formulation was prepared and tested in the manner described in

Example 3 with the dispersant being the sodium salt of a copolymer of n-decene and maleic

anhydride. Results are shown in TABLE 1.

Example 5.

Example 3 with the dispersant being the sodium salt of a copolymer of diisobutylene and

maleic anhydride of approximate molecular weight 20,000 to 30,000. Results are shown in TABLE 1. Example 6.

A WG formulation was prepared and tested as described in Example 3 with the dispersant

being the sodium salt of SMA 1000 (Atochem Inc) which is a 1: 1 molar ratio copolymer of

styrene and maleic anhydride. Results are shown in TABLE 1.

Example 7.

being the sodium salt of SMA 3000 (Atochem Inc) which is a 3: 1 molar ratio copolymer of

styrene and maleic anhydride. Results are shown in TABLE 1.

Example 8.

being the sodium salt of GANTREZ AN 119 resin (Rhodia Inc) which is a copolymer of

methylvinyl ether and maleic anhydride. Results are shown in TABLE 1.

Example 9

A Simazine 900g/kg WG formulation of the following composition was prepared :

Simazine tech. (98% w/w) 91.8 % w/w

ATPLUS G73050 1.5 (now sold under the trade mark TERWET 7050, Orica Australia Pty Ltd)

DISPERSANT 3.1

Kaolin 3.1

Water 0.5% The dispersant used was the sodium salt of a copolymer of n-octene and maleic anhydride

derivatised by reaction with moφholine to give a moφholine amide derivative. The granules

were prepared and tested in the manner described in Example 1. Results are shown in

TABLE 2.

Example 10

Example 9 with the dispersant being the sodium salt of the moφholine amide derivative of

a co-polymer of n-decene and maleic anhydride. Results are shown in TABLE 2.

Example 11

SMA 1000 (Atochem Inc), a 1: 1 molar ratio copolymer of styrene and maleic anhydride.

Results are shown in TABLE 2.

Example 12

SMA 3000 (Atochem Inc), a 3: 1 molar ratio copolymer of styrene and maleic anhydride.

Results are shown in TABLE 2. Example 13

Example 9 with the dispersant being the sodium salt of the aromatic sulphonated derivative

of SMA 1000 (Atochem Inc), a 1: 1 molar ratio copolymer of styrene and maleic anhydride.

Results are shown in TABLE 2.

Example 14

Example 9 with the dispersant being the sodium salt of the co-polymer of alphamethylstyrene

and maleic anhydride derivatised with ammonia to give the corresponding monoamide.

Results are shown in TABLE 2.

Example 15

Example 9 with the dispersant being the sodium salt of the copolymer of alphamethylstyrene

and maleic anhydride derivatised with ethanolamine to give the corresponding ethanolamide. Results are shown in TABLE 2.

Example 16

and maleic anhydride derivatised with n-butylamine to give the corresponding n-butylamide. Results are shown in TABLE 2.

Example 17

and maleic anhydride derivatised with moφholine to give the corresponding moφholine amide. Results are shown in Table 2.

Example 18 A Simazine 900g/kg WG formulation was prepared and tested in the manner described in

Example 9 with the dispersant being the sodium salt of the copolymer of dicyclopentadiene

and maleic anhydride derivatised moφholine to give the corresponding amide. Results are

shown in TABLE 2.

Example 19

Example 9 with the dispersant being a sulphonated derivative of the sodium salt of the copolymer of dicyclopentadiene and maleic anhydride. Results are shown in TABLE 2.

Example 20

A Simazine 900g/kg WG formulation was prepared and tested in the manner described in Example 9 with the dispersant being a sulphonated derivative of the sodium salt of the

copolymer of dimethyldicyclopentadiene and maleic anhydride. Results are shown in TABLE

2.

Example 21

Example 9 with the dispersant being the sodium salt of the copolymer of

dimethyldicyclopentadiene and maleic anhydride derivatised with moφholine to give the

corresponding moφholine amide. Results are shown in TABLE 2.

Example 22

Gantrez AN119(Rhodia Coφ.), a copolymer of methylvinyl ether and maleic anhydride

Results are shown in TABLE 2.

Example 23

Example 9 with the dispersant being the sodium salt of the cyclohexyl amide derivative of Gantrez AN119(Rhodia Coφ), a copolymer of methylvinyl ether and maleic anhydride Results are shown in TABLE 2. Example 24

An Atrazine 900g/Kg SC formulation of the following composition was prepared.

Atrazine tech. 97% w/w 51.5 % w/v

Monoethylene glycol 4.0

DISPERSANT 4

Silicone antifoam 0.2

Rhodopol 23 0.2 (Rhodia Inc.)

Proxel GXL 20 OJ (Zeneca pic)

Water. 55.0

The dispersant used was the sodium salt of a sulphonated copolymer of dicyclopentadiene

and maleic anhydride. The SC was prepared by dissolving the monoethylene glycol,

ATLOX 4896A and DISPERSANT in 85 % of the water and adding the Atrazine tech. and

antifoam with vigorous mixing to form a slurry or millbase premix. The premix is then

milled using a Dynomill laboratory scale bead mill to give a suitable particle size distribution

of > 98% of particles below 5 microns. The millbase thus obtained was then blended with

Proxel GXL 20(Zeneca pic) and Rodopol 23(Rhodia Inc.) in a premix and then made up to

the desired volume with the remaining water and mixed to a homogeneous mixture. The

SC thus obtained was of usable viscosity and was found to be storage stable after storage at

2 degrees C and 50 degrees C for one month, with minimal syneresis and thickening and no claying, sedimentation or aggregates being observed. P:\OPER\MLA\ICIIV.278 - 14/10/98

TABLE 1 WDG Results from Prior Art

T₀ initial results

T, after 1 month storage at 50°C T₃ after 3 months storage at 50°C

P \OPER\MLA\ICIIV 278 - 14/10/98

TABLE 2 WG Formulations using Dispersants of Second Embodiment

T_n initial results __nnt_ * Data not yet available

T" after 1 month storage at 50°C - Testing discontinued

Those skilled in the art will appreciate that the invention described herein is susceptible to

variations and modifications other than those specifically described. It is to be understood

that the invention includes all such variations and modifications which fall within its spirit

and scope. The invention also includes all of the steps, features, compositions and

compounds referred to or indicated in this specification, individually or collectively, and

any and all combinations of any two or more of said steps or features.

Claims

1. A method of dispersing an insoluble material in an aqueous solution comprising the

following steps:

dispersant comprising a copolymer wherein said copolymer comprises a residue of a first comonomer and a residue of a second comonomer, wherein said first

comonomer is an ╬▒,╬▓ -unsaturated oxyacid or anhydride and said second

comonomer is an olefin having at least one polymerizable double bond and wherein

at least one of said first comonomer and said second comonomer is substituted,

wherein the substituents for said first comonomer are selected from the group

consisting of esters, amides, thioesters and functional groups derived from reaction

with nucleophilic reagents and wherein the substituents for the second comonomer

are selected from the group consisting of epoxides; sulfonates; esters; amides; and

optionally substituted pendent aromatic and heteroaromatic groups wherein said

optional substituents are selected from the group consisting of sulfonates, nitrates,

phosphates and other substituents derived from reaction with electrophilic reagents.

(ii) dispersing said formulation in an aqueous medium.

2. A method according to claim 1 wherein the first comonomers are selected from the

group consisting of fumaric acid, maleic acid and anhydrides, and the esters, amides and

imides derived from them, itaconic acid and anhydride and the corresponding esters

amides and imides derived from them, acrylic and methacrylic acids, esters and amides,

vinylphosphonic acid and the corresponding esters and amides derived from it and

ethylene sulphonic acid and the esters and amides derived from it.

3. A method according to claim 1 wherein the second comonomer is selected from the

group consisting of ╬▓-pinene, 5-ethylidene-2-norboraene, methylene cyclohexane and methylene cyclopentane.

4. A method according to claim 1 wherein the second comonomer is selected from the

group consisting of substituted and unsubstituted norbornene, cyclopentadiene and

substituted cyclopentadienes, substituted and unsubstituted dicyclopentadienes ,

cyclohexenes, furans and indenes.

5. A method according to claim 1 wherein the second comonomer is selected from the

group consisting of limonene and similar te╧åenes, vinyl cyclohexanes, vinyl

cyclohexenes, vinyl pyridines, vinyl thiophenes, vinyl naphthalenes, vinyl furans, vinyl

pyrans and, vinyl pyrrolidones.

6. A method according to claim 1 wherein the second comonomer is an ╬▒-olefin having an alkyl group selected from the group consisting of diisobutylene, isobutylene, n-

octene, n-decene, allyglycidylether or vinylisobutylether.

7. A method according to claim 1 wherein the first comonomer has a structure I

O

RΓÇ₧ C= CR₂ Y OR_!

R,

wherein R_r is M a metal, quaternary ammonium, phosphonium or sulphonium residue, R₂

is hydrogen or C, to C₄ alkyl, Y is a carbon atom, O=S, or POR, a hydrogen atom or

alkyl radical having from 1 to 10 carbon atoms (or carboxylated such radical) and R₄ is H,

an alkyl radical or a carboxylic acid derivative of form II

o

II c R<

II

wherein R₅ is OR^, NR_<;R₇ , S ^, wherein Re ,R₇ , are H, alkyl, O-alkyl, or alkyl groups with a hetero atom substituent.

8. A method according to claim 1 wherein the second comonomer has a structure III

CH₉ = C

Re

III

wherein R₈ represents hydrogen, a straight or branched chain alkyl of from 1-4 carbon

atoms, R₉ represents hydrogen, a branched chain alkylradical from 1-12 carbon atoms, or

cycloalkyl radical,

and/or a vinyl compound of formula IV

-^R10

CH, C

^R11

IV wherein R₁₀ is a straight or branched chain alkyl radical of from 1-4 carbons and R_n is

given by formula V, VI or VII,

V VI VII

wherein R₁₂ represents one or more alkyl radicals or one or more of H,CI,OR and SO₃R,

VIII,

VIII

wherein R₁₃ is Cl, or $0^ , alkyl, O-alkyl, O-aryl and R₁₄, represents from 4-20 carbon atoms such as to make H a cyclic or polycyclic alkane or polyalkenyl compound, R₁₅ , is

an epoxide or SO₃R_! reacted with an unsaturated portion of the ring comprising R₁₄;

and/or an exocyclic olefin shown by formula IX

IX

and/or an internal olefin shown by formula X,

X

where R_j, is the same or different and as hereinabove defined.

9. A method according to claim 1 wherein the copolymer contains additional

comonomer residues which will not substantially change the character of the copolymer.

10. An agricultural formulation comprising at least one insoluble material and at least

one dispersant comprising a copolymer wherein said copolymer comprises a residue of a

first comonomer and a residue of a second comonomer, wherein said first comonomer is

an ╬▒,╬▓-unsaturated oxyacid or anhydride and said second comonomer is an olefin having

at least one polymerizable double bond and wherein at least one of said first comonomer

and said second comonomer is substituted, wherein the substituents for said first

comonomer are selected from the group consisting of esters, amides, thioesters and

functional groups derived from reaction with nucleophilic reagents and wherein the

substituents for the second comonomer are selected from the group consisting of epoxides;

sulfonates; esters; amides; and optionally substituted pendent aromatic and heteroaromatic

groups wherein said optional substituents are selected from the group consisting of

sulfonates, nitrates, phosphates and other substituents derived from reaction with

electrophilic reagents.

11. An agricultural formulation according to claim 10 wherein the formulation is in the

form of a suspension concentrate (SC), a wettable powder (WP) or a water dispersible

granule (WG).

12. A method according to claim 10 wherein first comonomers are selected from the

ethylene sulphonic acid and the esters and amides derived from it.

13. A method according to claim 10 wherein the second comonomers are selected from

the group consisting of ╬▓-pinene, 5-ethylidene-2-norbornene, methylene cyclohexane and

methylene cyclopentane.

14. A method according to claim 10 wherein the second comonomers are selected from

the group consisting of substituted and unsubstituted norbornene, cyclopentadiene and

cyclohexenes, furans and indenes.

15. A method according to claim 10 wherein the second comonomers are selected from

the group consisting of limonene and similar te╧åenes, vinyl cyclohexanes, vinyl cyclohexenes, vinyl pyridines, vinyl thiophenes, vinyl naphthalenes, vinyl furans, vinyl

pyrans and, vinyl pyrrolidones.

16. A method according to claim 10 wherein the first comonomers are selected from

the group consisting of an ╬▒-olefin having an alkyl group selected from the group

consisting of diisobutylene, isobutylene, n-octene, n-decene, allylglycidylether or

vinylisobutylether.

17. A method according to claim 10 wherein the first comonomers are selected from

the group consisting of structure I

O

II

R,

I

is hydrogen or C, to C₄ alkyl, Y is a carbon atom, O=S, or POR_! a hydrogen atom or

alkyl radical having from 1 to 10 carbon atoms (or carboxylated such radical) and P^ is H,

an alkyl radical or a carboxylic acid derivative of form II o

II c R.

II

wherein R₅ is ORg, N^R, , SRg,

wherein R^ ,R₇ , are H, alkyl, O-alkyl, or alkyl groups with a hetero atom substituent.

18. A method according to claim 10 wherein the first comonomer is selected from the

group consisting of III

CH^

Re

III

wherein R_g represents hydrogen, a straight or branched chain alkyl of from 1-4 carbon

atoms, Rg represents hydrogen, a branched chain alkylradical from 1-12 carbon atoms, or cycloalkyl radical, and/or a vinyl compound of formula IV

-^R10

CH: C

R 11

IV

wherein R₁₀ is a straight or branched chain alkyl radical of from 1-4 carbons and R_n is

given by formula V, VI or VII,

VI VII

wherein R₁₂ represents one or more alkyl radicals or one or more of H,Cl,OR and SO₃Rj NO₂, PO₃R, and X is a hetero atom other than carbon; and/or an olefin shown by formula

VIII,

VIII

wherein R₁₃ is Cl, or SO₃R_! , alkyl, O-alkyl, O-aryl and R₁₄, represents from 4-20 carbon

atoms such as to make H a cyclic or polycyclic alkane or polyalkenyl compound, R₁₅ , is

an epoxide or SO₃R_j reacted with an unsaturated portion of the ring comprising R₁₄;

and/or an exocyclic olefin shown by formula IX

IX

and/or an internal olefin shown by formula X,

X

where R_<, is the same or different and as hereinabove defined.

19. A method according to claim 10 wherein the copolymer contains additional

20. An agricultural formulation according to claim 10 wherein the dispersant is readily

soluble in water.

21. An agricultural formulation according to claim 10 wherein the dispersant is an

agriculturally acceptable salt of the copolymer and wherein the salt comprises sodium, potassium and/or ammonium ions.

22. An agricultural formulation according to claim 10 wherein the copolymer is polyanionic.

23. .An agricultural formulation according to claim 10 wherein the copolymer is in the

form of its free acid.

5

24. a ai agricultural formulation according to claim 10 wherein the dispersant is a water-

soluble agriculturally acceptable derivative of the copolymer wherein said derivative is

selected from the group consisting of poly alky leneoxy derivatives, polyethyleneglycol

derivatives, poly amide derivatives and polyvinyl alcohol derivatives.

10

25. a n agricultural formulation according to claim 10 wherein copolymers are in the

range of from 1000 to 90000 daltons.

26. .An agricultural formulation according to claim 10 wherein copolymers are in the

15 range of from 1,000 to 30,000 daltons.

27. .An agricultural formulation according to claim 10 wherein copolymers are in the range of from 10,000 to 30,000 daltons.

20 28. a n agricultural formulation according to claim 10 wherein the water-insoluble

materials are selected from the group consisting of herbicides, insecticides, fungicides,

biocides, molluscicides, algaicides, plant growth regulators, anthelmintics, rodenticides,

nematocides, acaricides, amoebicides, protozoacides, fertilizers, crop safeners fillers and carriers and other adjuvants.

29. .An agricultural formulation according to claim 10 wherein the formulation further

comprises a surfactant wetting agent.

30. A method of making an agrochemical formulation comprising the steps of:

copolymer wherein said copolymer comprises a residue of a first comonomer and a

residue of a second comonomer, wherein said first comonomer is an ╬▒,╬▓-

unsaturated oxyacid or anhydride and said second comonomer is an olefin having

at least one polymerizable double bond and wherein at least one of said first

said first comonomer are selected from the group consisting of esters, amides,

thioesters and functional groups derived from reaction with nucleophilic reagents

and wherein the substituents for the second comonomer are selected from the group

consisting of epoxides; sulfonates; esters; amides; and optionally substituted

pendent aromatic and heteroaromatic groups wherein said optional substituents are

selected from the group consisting of sulfonates, nitrates, phosphates and other

substituents derived from reaction with electrophilic reagents;

31. A method according to claim 30 comprising the steps of: (i) combining at least one insoluble material, and at least one dispersant comprising a

copolymer wherein said copolymer comprises a residue of a first comonomer and a

residue of a second comonomer, wherein said first comonomer is an ╬▒,╬▓- unsaturated oxyacid or anhydride and said second comonomer is an olefin having

at least one polymerizable double bond and wherein at least one of said first

said first comonomer are selected from the group consisting of esters, amides,

consisting of epoxides; sulfonates; esters; amides; and optionally substituted

substituents derived from reaction with electrophilic reagents;

(ii) milling said combination to a particle size range in order to obtain a stable, readily-

suspendible aqueous dispersion; and

(iii) stabilising said aqueous dispersion to obtain an SC formulation suitable for dilution in water for agricultural use.

32. A method according to claim 30 comprising the steps of: (i) combining at least one insoluble material, with at least one dispersant comprising

a copolymer wherein said copolymer comprises a residue of a first comonomer and a residue of a second comonomer, wherein said first comonomer is an ╬▒,╬▓-

unsaturated oxyacid or anhydride and said second comonomer is an olefin having

at least one polymerizable double bond and wherein at least one of said first

said first comonomer are selected from the group consisting of esters, amides,

consisting of epoxides; sulfonates; esters; amides; and optionally substituted pendent aromatic and heteroaromatic groups wherein said optional substituents are

substituents derived from reaction with electrophilic reagents; and

(ii) milling said combination to a desired particle size to obtain a homogeneous

wettable powder (WP) formulation.

33. A method according to claim 30 comprising the steps of:

(i) combining at least one insoluble material suitable for agricultural use with at least

one dispersant comprising a copolymer wherein said copolymer comprises a residue of a first comonomer and a residue of a second comonomer, wherein said

first comonomer is an ╬▒,╬▓-unsaturated oxyacid or anhydride and said second comonomer is an olefin having at least one polymerizable double bond and wherein

at least one of said first comonomer and said second comonomer is substituted, wherein the substituents for said first comonomer are selected from the group

optionally substituted pendent aromatic and heteroaromatic groups wherein said

phosphates and other substituents derived from reaction with electrophilic reagents;

and

(ii) blending said combination to obtain a homogeneous wettable powder (WP)

formulation.

34. A method according to claim 30 comprising the steps of:

one dispersant comprising a copolymer wherein said copolymer comprises a residue of a first comonomer and a residue of a second comonomer, wherein said first comonomer is an ╬▒,╬▓-unsaturated oxyacid or anhydride and said second comonomer is an olefin having at least one polymerizable double bond and wherein

at least one of said first comonomer and said second comonomer is substituted,

wherein the substituents for said first comonomer are selected from the group

optionally substituted pendent aromatic and heteroaromatic groups wherein said

(ii) agglomerating said combination to form discrete granular materials; and

35. A method according to claim 30 wherein the first comonomers are selected from

the group consisting of fumaric acid, maleic acid and anhydrides, and the esters, amides

and imides derived from them, itaconic acid and anhydride and the corresponding esters amides and imides derived from them, acrylic and methacrylic acids, esters and amides,

ethylene sulphonic acid and the esters and amides derived from it.

36. A method according to claim 30 wherein the second comonomer is selected from

methylene cyclopentane.

5 37. A method according to claim 30 wherein the second comonomer is selected from

cyclohexenes, furans and indenes.

10 38. A method according to claim 30 wherein the second comonomer is selected from

the group consisting of limonene and similar te╧åenes, vinyl cyclohexanes, vinyl

pyrans and, vinyl pyrrolidones.

15 39. A method according to claim 30 wherein the second comonomer is an ╬▒-olefin

having an alkyl group selected from the group consisting of diisobutylene, isobutylene, n-

octene, n-decene, allylglycidylether or vinylisobutylether.

40. A method according to claim 30 wherein the first comonomer has a structure I 20 0

R-,

I

wherein R_j is M a metal, quaternary ammonium, phosphonium or sulphonium residue, R₂

is hydrogen or C, to C₄ alkyl, Y is a carbon atom, O=S, or PORj a hydrogen atom or

an alkyl radical or a carboxylic acid derivative of form II

0 II c R<

II

wherein R₅ is OR^, NRgR-, , SR^

wherein R_<; ,R₇ , are H, alkyl, O-alkyl, or alkyl groups with a hetero atom substituent.

41. A method according to claim 30 wherein the second comonomer has a structure III R.

CH: c

Re

III

atoms, Ro represents hydrogen, a branched chain alkylradical from 1-12 carbon atoms, or

cycloalkyl radical, and/or a vinyl compound of formula IV

,R 10

CH₉ = C

^R11

IV

wherein R₁₀ is a straight or branched chain alkyl radical of from 1-4 carbons and R_n is given by formula V, VI or Nil,

VI VII

wherein R₁₂ represents one or more alkyl radicals or one or more of H,Cl,OR and SO₃R_!

NO₂, PO₃R_! and X is a hetero atom other than carbon; and/or an olefin shown by formula

VIII,

VIII

wherein R is Cl, or SO₃R, , alkyl, O-alkyl, O-aryl and R₁₄, represents from 4-20 carbon atoms such as to make H a cyclic or polycyclic alkane or polyalkenyl compound, R╬╣₅ , is an epoxide or SO₃R_╬╣ reacted with an unsaturated portion of the ring comprising R₁₄; and/or an exocyclic olefin shown by formula IX

IX

and/or an internal olefin shown by formula X,

X where Rg is the same or different and as hereinabove defined.

42. A method according to claim 30 wherein the copolymer contains additional comonomer residues which will not substantially change the character of the polymer.

43. An agricultural formulation according to claim 30 wherein the dispersant is readily

soluble in water.

44. An agricultural formulation according to claim 30 wherein the dispersant is an

agriculturally acceptable salt of the copolymer and wherein the salt comprises sodium,

potassium and/or ammonium ions.

45. An agricultural formulation according to claim 30 wherein the copolymer is

polyanionic.

46. An agricultural formulation according to claim 30 wherein the copolymer is in the form of its free acid.

47. An agricultural formulation according to claim 30 wherein the dispersant is a water- soluble agriculturally acceptable derivative of the copolymer wherein said derivative is

selected from the group consisting of polyalkyleneoxy derivatives, polyethyleneglycol

derivatives, polyamide derivatives and polyvinyl alcohol derivatives.

48. An agricultural formulation according to claim 30 wherein copolymers are in the

range of from 1000 to 90000 daltons.

49. .An agricultural formulation according to claim 30 wherein copolymers are in the

5 range of from 1,000 to 30,000 daltons.

50. An agricultural formulation according to claim 30 wherein copolymers are in the

range of from 1,000 to 10,000 daltons.

10 51. An agricultural formulation according to claim 30 wherein the water-insoluble

nematocides, acaricides, amoebicides, protozoacides, fertilizers, crop safeners fillers and

carriers and other adjuvants.

15

52. a n agricultural formulation according to claim 30 wherein the formulation further comprises a surfactant wetting agent.

53. A method according to any one of claims 32 to 34 wherein said dispersant achieves a 0 percentage suspensibility of greater than 80%.

54. A method according to claim 31 wherein said dispersant achieves a percentage suspensibility of greater than 90%.

55. A method according to either claim 32 or claim 33 wherein the milling step produces

a mean particle size in the range of from 5 to 15╬╝m.

56. A method according to claim 55 wherein the wettable powder has a wettability of

5 less than 1 minute and a suspensibility above 80%.

57. A method according to claim 34 wherein the milling step produces a mean particle

size in the range of from 5 to 15╬╝m.

10 58. A method according to claim 34 wherein the formulation has a dispersion time of less

than 1 minute.

59. A method according to claim 34 wherein the formulation has a dispersion time of less

than 20 seconds.

15

60. A method according to claim 34 wherein the formulation has a suspensibility of above 80%.

61. A method according to claim 34 wherein the formulation has a wet sieve retention.

0 For a 150 ╬╝m sieve is less than 0.1 % retained material and is for a 53 ╬╝m sieve is less

than 0.6% .

62. A method according to claim 31 wherein the milling step produces a mean particle size of less than 5╬╝m.

63. A method according to claim 31 wherein the milling step produces a mean particle

size in the range of from 1 to 3 ╬╝m.

64. An agricultural formulation produced by the method of any one of claims 31 to 34.

65. a method of treatment of a substrate with an insoluble material comprising the

following steps:

dispersant comprising a copolymer wherein said copolymer comprises a residue of

a first comonomer and a residue of a second comonomer, wherein said first

comonomer is an ╬▒,╬▓ -unsaturated oxyacid or anhydride and said second

at least one of said first comonomer and said second comonomer is substituted,

wherein the substituents for said first comonomer are selected from the group

optionally substituted pendent aromatic and heteroaromatic groups wherein said

optional substituents are selected from the group consisting of sulfonates, nitrates, phosphates and other substituents derived from reaction with electrophilic reagents;

(ii) dispersing said formulation in an aqueous medium; and

5 (iii) applying the dispersed formulation to a substrate.

66. A method according to claim 65 wherein the first comonomers are selected from

10 and imides derived from them, itaconic acid and anhydride and the corresponding esters

ethylene sulphonic acid and the esters and amides derived from it.

15 67. A method according to claim 65 wherein the second comonomer is selected from

methylene cyclopentane.

68. A method according to claim 65 wherein the second comonomer is selected from

0 the group consisting of substituted and unsubstituted norbornene, cyclopentadiene and

substituted cyclopentadienes, substituted and unsubstituted dicyclopentadienes , cyclohexenes, furans and indenes.

69. A method according to claim 65 wherein the second comonomer is selected from

pyrans and, vinyl pyrrolidones.

5

70. A method according to claim 65 wherein the second comonomer is an ╬▒-olefin

octene, n-decene, allylglycidylether or vinylisobutylether.

10 71. A method according to claim 65 wherein the first comonomer has a structure I

O

R,

wherein Rj is M a metal, quaternary ammonium, phosphonium or sulphonium residue, R₂

15 is hydrogen or C, to C₄ alkyl, Y is a carbon atom, O=S, or POR_! a hydrogen atom or

alkyl radical having from 1 to 10 carbon atoms (or carboxylated such radical) and R^ is H, an alkyl radical or a carboxylic acid derivative of form II o

II C

II

wherein R₅ is OR^, NR,;R₇ , SR^

wherein R₆ ,R₇ , are H, alkyl, O-alkyl, or alkyl groups with a hetero atom substituent.

72. A method according to claim 65 wherein the second comonomer has a structure III

CH: C

Re

III

cycloalkyl radical,

and/or a vinyl compound of formula IN R 10

CH? ⁼ C

R 11

IV

wherein R₁₀ is a straight or branched chain alkyl radical of from 1-4 carbons and R_╧Ç is

given by formula V, VI or VII,

V VI VII

NO₂, PO₃Rj and X is a hetero atom other than carbon; and/or an olefin shown by formula VIII,

VIII

wherein R₁₃ is Cl, or SO₃R, , alkyl, O-alkyl, O-aryl and R₁₄, represents from 4-20 carbon

and/or an exocyclic olefin shown by formula IX

IX

and/or an internal olefin shown by formula X,

X

where Rg is the same or different and as hereinabove defined.

73. A method according to claim 65 wherein the copolymer contains additional

74. An agricultural formulation according to claim 65 wherein the dispersant is readily

soluble in water.

75. An agricultural formulation according to claim 65 wherein the dispersant is an

potassium and/or ammonium ions.

76. An agricultural formulation according to claim 65 wherein the copolymer is polyanionic.

77. An agricultural formulation according to claim 65 wherein the copolymer is in the

form of its free acid.

5

78. An agricultural formulation according to claim 65 wherein the dispersant is a water-

derivatives, polyamide derivatives and polyvinyl alcohol derivatives.

10

79. An agricultural formulation according to claim 65 wherein copolymers are in the

range of from 1000 to 90000 daltons.

80. .An agricultural formulation according to claim 65 wherein copolymers are in the

15 range of from 1000 to 30000 daltons.

81. a n agricultural formulation according to claim 65 wherein copolymers are in the range of from 1000 to 10000 daltons.

20 82. An agricultural formulation according to claim 65 wherein the water-insoluble

83 An agricultural formulation according to claim 65 wherein the formulation further comprises a surfactant wetting agent