The present disclosure relates to coatings and/or binders, particularly (but not exclusively) coatings for seeds and the like.

The present invention concerns coatings and/or binders. More particularly, but not exclusively, this invention makes use of particular polymers as binders and/or as a coating or in additive manufacturing.

Many current seed coatings are based on acrylic polymers. There are concerns that acrylic polymers break down to form nanoplastics, which may be considered to be particles of size from 1 to 1 OOOnm having a colloidal behaviour. There are concerns that such nanoplastics are harmful to the environment and use of such nanoplastics or materials that break-down to form such nanoplastics may be controlled or even prohibited by legislation. There is therefore a desire to find alternatives to seed coatings based on acrylic polymers.

Water-soluble polyvinyl alcohols are currently used in seed coatings. However, there is a tension between the desire to use a coating composition with a relatively high total solid content to provide a coating of a desired thickness and the high undesirably high viscosities usually associated with coating compositions of high total solid content. Oftentimes, a relatively high solid content is desirable in order to provide a relatively thick coating and to reduce the energy demand to dry the coating (by reducing the water content thereof). Compositions with such relatively high total solid content may be very viscous and therefore difficult to use.

The present invention seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved coating composition, in particular, but not exclusively an improved seed coating composition. SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention, there is provided use of a polymer as a coating, the polymer comprising (C=C)-(C=C)-C=0 moieties, the polymer comprising residues of:

( i ) at least one monofunctional monomer having one polymerisable double bond per molecule;

( i i ) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii ) at least one chain transfer agent comprising an aldehyde or ketone.

The polymer may optionally comprise residues of one or more of: one or more solvent components, one or more initiator, and a second chain transfer agent. The second chain transfer agent may, for example, be used to introduce certain functionalities into the polymer, as described in relation to the method of the first aspect of the present invention.

The polymer may be substantially as described in WO2015/145173.

The polymer may, of course, comprise residues of more than one monofunctional monomer, and/or more than one multifunctional monomer.

Those skilled in the art will realise that the residues may be post-treated. For example, the polymer may comprise residues of vinyl acetate or other acetate comprising a polymerisable C=C double bond, in the form of acetate groups attached to a polymer backbone. These acetate groups may be hydrolysed to form hydroxyl groups. Furthermore, the polymer may comprise residues of dialkyl maleate in the form of alkanol groups attached to a polymer backbone. These alkanol groups may be hydrolysed to form carboxylic acid groups.

The polymer may be hyperbranched. Within this application the term "hyperbranching" is understood in its broadest sense and is used consistent with Pure Appl. Chem., Vol. 81, No. 6, pp. 1131-1186, 2009. doi: 10.1351/P AC-REC-08-01 -30 © 2009 IUP AC, Publication date (Web): 5 May 2009; International Union of Pure and Applied Chemistry Polymer Division; Commission on macromolecular nomenclature; subcommittee on macromolecular terminology and subcommittee on polymer terminology glossary of class names of polymers based on chemical structure and molecular architecture.

In its broadest terms, hyperbranching refers to a polymer composed of highly branched macromolecules in which any linear subchain may lead in either direction to at least two other sub-chains.

The polymer may be a poly(alkenyl alkanoate) or a poly (alkenyl alcohol)-co- poly(alkenyl alkanoate) or a poly(alkyl alcohol)-co-poly (alkyl alkenoate). The polymer may therefore comprise ester groups, carboxylic acid groups and hydroxyl groups, for example. The polymer may have a degree of hydrolysis of at least 60mol%, optionally at least 65mol%, optionally at least 70mol%, optionally no more than 95mol% and optionally no more than 90mol%. This relatively high degree of hydrolysis has been found to be effective in promoting good behaviour as a primary suspending agent in certain polymerisation reactions, such as the polymerisation of alkenyl compounds, such as vinyl chloride and its copolymers.

The polymer may optionally have a weight averaged molecular weight (M _w ) of at least 3,000, optionally at least 10,000, optionally at least 20,000, optionally at least 40,000 and optionally at least 50,000. The polymer may optionally have a weight averaged molecular weight (M _w ) of no more than optionally no more than 70,000, optionally no more than 80,000, optionally no more than 100,000, optionally no more than 200,000, optionally no more than 300,000, optionally no more than 400,000, optionally no more than 500,000, optionally no more than 750,000 and no more than I,OOO,OOO^.ihoI ¹ .

The polymer may optionally have a number averaged molecular weight (M _n ) of at least 1,500, optionally at least 2,000, optionally at least 2,500, optionally at least 3,000 and optionally at least 4,000. The polymer may optionally have a number averaged molecular weight (M _n ) of no more than 6,000, optionally no more than 7,000, optionally no more than 8,000, optionally no more than 10,000, optionally no more than 12,000, optionally no more than 15,000, optionally no more than 25,000, optionally no more than 30,000, optionally no more than 50,000, optionally no more than 100,000, optionally no more than 200,000, optionally no more than 300,000, optionally no more than 400,000 and optionally no more than SOO OOOg.mol ¹ .

M _w and M _n were measured by size exclusion chromatography (SEC) (also known as gel permeation chromatography, GPC) in THF solution. The sample was injected into a PL- GPC-50 system via autosampler, using stabilised THF as a mobile phase and three PL gel columns in series, each column having dimensions of 300mm x 7.5mm x 10pm. The system was calibrated with PS High Easivials® polystyrene standards in the Mp molecular weight range of 6,035,000 - SSOg.mol- ¹ (supplied by Agilent Technologies).

The dispersity (defined as M _w /M _n , often known as a polydispersity, or polydispersity index (PDI)) of the polymer may be at least 2, at least 3, at least 5 and optionally at least 10. The dispersity may optionally be no more than 20, optionally no more than 25, optionally no more than 30, optionally no more than 50, optionally no more than 100, optionally no more than 150 and optionally no more than 200. Optionally, the dispersity of the polymer may be from 3 to 200, optionally from 5 to 150, optionally from 3 to 30 and optionally from 5 to 25.

The viscosity of a 4% (w/w) solution of the hydrolysed polymer at 20°C, typically a poly (vinyl acetate)-co- poly(vinyl alcohol), may be no more than 50mPa.s, optionally no more than 50mPa.s, optionally no more than 20mPa.s, optionally no more than lOmPaS, optionally no more than 5mPa.s and optionally no more than 5mPas. Optionally, the viscosity is at least ImPa.s, optionally at least 2mPa.s and optionally at least 5mPa.s.

The viscosity of 4% (w/w) solution mentioned above was measured by dissolving dried material in distilled water to give the desired concentration, placing the required quantity of solution in to a calibrated U-tube viscometer (the capillary size of which was chosen to give a flow time of approximately 60 seconds), equilibrated at 20±0.2°C in a water bath. The time for the equilibrated solution to flow between 2 marks on the capillary is used to calculate the solution viscosity. The solution viscosity was calculated thus: viscosity = (recorded flow time) x (density of the 4% (w/w) solution) x (calibration factor for the viscometer).

Solution viscosity measurements on poly(alkenyl alkanoates), such as poly(vinyl acetate) were made to determine the K- value. In this case, the K-value measurements were performed using a 2% (w/v) solution of the polymer in ethyl acetate in a "C" U-tube viscometer equilibrated at 20±0.2°C in a water bath. The time for the equilibrated solution to flow between 2 marks on the capillary is used to calculate the relative solution viscosity.

The relative solution viscosity = (recorded flow time of the 2% (w/v) solution) /

(recorded flow time of ethyl acetate).

The K-value may be at least 10, at least 15, at least 20 and optionally at least 25. The K- value may optionally be no more than 40, no more than 50, no more than 60, no more than 70, no more than 80 and optionally no more than 100. The K- value may be from 20 to 70, optionally from 25 to 70, optionally from 25 to 60 and optionally from 30 to 60.

The polymer of the present invention optionally comprises more C=C-C=C-C=0 moieties than (C=C)3CO moieties, optionally significantly more. The intensity of the UV absorbance peak at 280nm (attributed to the C=C-C=C-C=0 moiety) generated by a solution of the polymer may optionally be greater than the intensity of the UV absorbance peak at 320nm (attributed to the (C=C)3CO moiety), the peak at 280nm optionally having at least two times the intensity, optionally at least three times the intensity, optionally at least four times the intensity, optionally at least 5 times, and optionally at least 6 times the intensity of the peak at 320nm. Those skilled in the art will realise that the precise wavelengths at which the peaks are observed may vary slightly from 280nm and 320nm.

For the avoidance of doubt the intensity of the UV absorbance peaks were measured thus. A solution or dispersion of the polymer was formed in distilled water, typically at a concentration of 0.1% or 0.2% (w/w). The UV spectrum of the solution is then recorded on a UV single beam spectrometer (Thermo Spectronic), using a 10mm light path quartz cell, the spectrum being corrected for the solvent/dispersant (water). The absorbance is multiplied by a suitable number (typically 10 or 5, depending on the initial concentration used) to provide an absorbance at 1% (w/w) concentration of polymer.

For the avoidance of doubt, the polymer is optionally formed by free radical polymerisation, and may therefore comprise residues of reagents associated with free radical polymerisation, such as appropriate initiators.

At least one chain transfer agent comprising an aldehyde or ketone may comprise from 1 to 20, optionally from 1 to 10, optionally from 2 to 6 and optionally from 2 to 4 carbon atoms. For example, at least one (and optionally each) of said chain transfer agents may comprise acetaldehyde, propionaldehyde (often known as propanal), butyraldehyde (often known as butanal), isobutyraldehyde, pentanal, hexanal, isovaleraldehyde, 5- chloropentenal, 5,5-Dimethyl-l,3-cyclohexanedione (also known as dimedone), cyclohexanecarbaldehyde, 3-methylcycloheanecarbaldehyde, 3,3- dibromocylopentanecarbaldehyde, trans-2-methylcyclopentanecarbaldehyde, benzaldehyde, substituted benzaldehydes, crotonaldehyde, paraldehyde, chloral, pentanedial, butanedial, 4-hydroxbutanal, 4-hydroxy-3-methylbutanal or acetone, butan-

2-one (often known as methyl ethyl ketone or MEK), methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, ethyl propyl ketone, diethyl ketone, acetophenone, cyclohexanone, acetylacetone, benzophenone,or oxopentanal, 3,4- dioxopentanal, 3 -methyl-3 -oxo-butanal, butane-2,3 -dione), 2,4-pentanedione, 2,3- hexanedione, cyclopentanone, 2-bromocyclopentanone, 4-hydroxycyclohexanone, 2- bromo-5-methylcyclohexanone, 1 ,4-cyclohexanedione, 1,2-cyclopentanedione, 4- hydroxy-2-butanone, l,5-dihydroxy-3-pentanone, 4-penten-2-one, trans-3-pentenal, (E)-

3 -methyl-3 -pentenal, (Z)-5-bromo-4-hexen-3-one, benzoin, furfural or substituted furfurals, and the like. The polymer may comprise residues of more than one chain transfer agent. For example, the method may comprise providing a first chain transfer agent comprising a carbonyl group such as an aldehyde or a ketone, and a second chain transfer agent. The second chain transfer agent may optionally comprise an aldehyde or ketone, or the second chain transfer agent may optionally not comprise an aldehyde or ketone.

The amount of chain transfer agent comprising an aldehyde or ketone may be from 0.005 to 50mol% of the amount of monofunctional monomer i.e. the number of moles of chain transfer agent comprising an aldehyde or ketone may optionally be from 0.005 to 50% of the number of moles of monofunctional monomer. This should be calculated using the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of monofunctional monomer, even if more than one monofunctional monomer and/or more than one chain transfer agent comprising an aldehyde or ketone is used.

The number of residues of chain transfer agent comprising an aldehyde or ketone may optionally be at least 0.005mol%, at least 0.05mol%, at least 0.5mol%, at least lmol%, at least 5mol%, at least 7mol%, at least 10mol%, no more than 20mol%, no more than 25mol%, no more than 30mol%, no more than 40mol%, no more than 45mol%, and optionally no more than 50mol% of the number of residues of monofunctional monomer, based on the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of monofunctional monomer.

Optionally, the amount of chain transfer agent comprising an aldehyde or ketone may optionally be from 0.5 to 50mol%, from 0.5 to 45mol%, from 0.5 to 30mol%, from 1 to 25mol%, from 5 to 45mol%, from 5 to 25mol%, from 7 to 40mol%, from 10 to 25mol% and optionally from 10 to 20mol% of the amount of monofunctional monomer, based on the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of monofunctional monomer. The amount of said chain transfer agent may, for example, depend on the nature of the solvent used. For example, some solvents have a relatively high chain transfer constant for the polymerisation reaction in question, and therefore it may not be necessary to use large amounts of said chain transfer agent in order to inhibit the formation of gels. For example, a solvent which comprises a relatively high isopropanol content reduces the amount of chain transfer agent required to inhibit gel formation when the monofunctional monomer is vinyl acetate because the isopropanol has a relatively high chain transfer constant for the polymerisation of vinyl acetate. However, those skilled in the art will realise that incorporation of a solvent residue, instead of a chain transfer agent residue, into a polymer may not be desirable from the point of view of incorporating into the polymer the requisite carbonyl functionality associated with the chain transfer agent residue from an aldehyde or ketone. Those skilled in the art will realise that solvents with very low chain transfer constants may be used.

The ratio of the number of moles of the chain transfer agent comprising an aldehyde or ketone to the number of moles of multifunctional monomer may be at least 10: 1, at least 20:1, at least 30:1, at least 50:1, at least 70:1, at least 100:1 and at least 120:1, based on the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of multifunctional monomer. The ratio of the number of moles of the chain transfer agent comprising an aldehyde or ketone to the number of moles of multifunctional monomer may be no more than 100: 1 , no more than 120: 1 , no more than 150:1, no more than 200:1 and optionally no more than 300:1, based on the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of multifunctional monomer. For example, for solution polymerisation, the relative amount of said chain transfer agent is typically higher than for a suspension polymerisation and therefore the ratio in solution polymerisation may be, for example, at least 50:1, optionally at least 70:1, optionally at least 90:1, optionally no more than 150:1, optionally no more than 200:1 and optionally no more than 300: 1, based on the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of multifunctional monomer. For example, the ratio of the number of moles of the chain transfer agent comprising an aldehyde or ketone to the number of moles of multifunctional monomer may be from 30:1 to 200:1, optionally from 50:1 to 150:1 and optionally from 70: 1 to 120: 1, based on the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of multifunctional monomer.

For suspension polymerisation, the ratio may be lower e.g. at least 30:1, at least 50:1, optionally no more than 100: 1 and optionally no more than 150:1, based on the total amount of chain transfer agent comprising an aldehyde or ketone and the total amount of multifunctional monomer.

Each monofunctional monomer comprises one (and only one) polymerisable carbon- carbon double bond per molecule. The carbon-carbon double bond will undergo an addition polymerisation reaction to form a polymer.

At least one monofunctional monomer may comprise other unsaturated groups, for example, such as a C=0 double bond.

Each monofunctional monomer may comprise any monomer which can be polymerised by a free radical mechanism. The term “monomer” also includes suitably reactive oligomers (typically comprising fewer than 5 repeat units), or polymers (typically comprising 5 or more repeat units).

The polymerisable carbon-carbon double bond of at least one (and optionally each) monofunctional monomer may be in the form of an ethylenic carbon-carbon double bond.

At least one (and optionally each) monofunctional monomer may comprise from 1 to 20 carbon atoms, for example, but may optionally comprise more than 20 carbon atoms. Optionally, the monofunctional monomer may comprise from 1 to 10, optionally from 2 to 8 and optionally from 3 to 6 carbon atoms. The molecular mass of at least one (and optionally each) monofunctional monomer may, for example, be less than 2000, optionally less than 1500, optionally less than 1000, optionally less than 500 and optionally less than 200g.mol ¹ .

At least one monofunctional monomer may, for example, be an ester (such as an alkenyl alkanoate [for example, vinyl acetate]). At least one monofunctional monomer may optionally be substituted. At least one monofunctional monomer may optionally comprise an optionally substituted alkenyl alkanoate.

As indicated above, the method may comprise providing at least one (and therefore, potentially more than one) monofunctional monomer.

Therefore, a second monofunctional monomer may be present. One or both of the first and second monofunctional monomers may, for example, be an ester (such as an alkenyl alkanoate [for example, vinyl propionate] or an alkyl alkenoate [such as methyl acrylate]), an amide (such as acrylamide), an acid anhydride (such as maleic anhydride), an acid (such as itaconic acid), an imide (such as a maleimide) or an alkene (such as ethylene). The second monofunctional monomer may optionally be substituted. The second monofunctional monomer may optionally comprise an optionally substituted alkenyl alkanoate or an optionally substituted alkyl alkenoate. The alkenyl alkanoate, if present, optionally comprises from 3 to 10 carbon atoms, optionally from 3 to 6 carbon atoms. The alkyl alkenoate, if present, optionally comprises from 3 to 10 carbon atoms, optionally from 3 to 6 carbon atoms.

At least one monofunctional monomer may comprise reactive moieties for subsequent reaction once a polymer has been synthesised. For example, at least one monofunctional monomer may comprise one or more ester moieties which may be hydrolysed to form hydroxyl or acid groups. The C-C double bond of at least one monofunctional monomer may be incorporated in an acyclic moiety. Alternatively, at least one monofunctional monomer may comprise one or more cyclic moieties, with the C-C double bond being incorporated into the cyclic moiety, such as in maleic anhydride.

Further examples of suitable monofunctional monomers include methyl vinyl acetate, propenyl acetate, methyl propenyl acetate, ethyl propenyl acetate, butenyl acetate, methyl butenyl acetate, vinyl propanoate, propenyl propanoate, vinyl benzoate, vinyl 4-t- butylbenzoate, vinyl chloroformate, vinyl cinnamate, vinyl decanoate, vinyl neodecanoate, vinyl propionoate, vinyl butyrate, vinyl pivalate, vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl 2-propylheptanoate, vinyl nonanoate, vinyl neononanoate, vinyl stearate, vinyl trifluoroacetate and vinyl valerate.

Examples of suitable monofunctional monomers include: ethylene, esters of monoethylenically unsaturated C3-C6 monocarboxylic acids with C1-C20 alkanols, cycloalkanols, phenyl-Cl-C4 alkanols or phenoxy-Cl-C4 alkanols, more particularly the aforementioned esters of acrylic acid and also the aforementioned esters of methacrylic acid; diesters of monoethylenically unsaturated C4-C6 dicarboxylic acids with C1-C20 alkanols, cycloalkanols, phenyl-Cl-C4 alkanols or phenoxy-Cl-C4 alkanols, more particularly the aforementioned esters of maleic acid and esters of fumaric acid; amides of monoethylenically unsaturated C3-C6-monocarboxylic acids with C4-C20- alkylamines or di-C2-C20-alkylamines; vinyl, allyl, and methallyl esters of saturated aliphatic carboxylic acids, in particular of saturated aliphatic C2-C18 monocarboxylic acids, especially the vinyl esters. Examples of esters of monoethylenically unsaturated C3-C6 monocarboxylic acids with C1-C20 alkanols, cycloalkanols, phenyl-Cl-C4 alkanols or phenoxy-Cl-C4 alkanols are, in particular, the esters of acrylic acid such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, 2- butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, 3 -propylheptyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate, cyclohexyl acrylate, benzyl acrylate, 2-phenylethyl acrylate, 1 -phenylethyl acrylate, 2- phenoxy ethyl acrylate, and also the esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, 2-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n- hexyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-phenylethyl methacrylate, 1 -phenylethyl methacrylate, and 2-phenoxyethyl methacrylate. Examples of diesters of monoethylenically unsaturated C4-C6 dicarboxylic acids with C1-C20 alkanols, cycloalkanols, phenyl-Cl-C4 alkanols or phenoxy-Cl-C4 alkanols are, in particular, the diesters of maleic acid and the diesters of fumaric acid, more particularly di-Cl-C20 alkyl maleinates and di-Cl-C20 alkyl fumarates such as dimethyl maleinate, diethyl maleinate, di-n-butyl maleinate, dimethyl fumarate, diethyl fumarate, and di-n- butyl fumarate. Examples of vinyl, allyl, and methallyl esters of saturated aliphatic carboxylic acid include in particular the vinyl esters of C2-C18 monocarboxylic acids such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl hexanoate, vinyl-2- ethylhexanoate, vinyl laurate, and vinyl stearate, and also the corresponding allyl and methallyl esters. Further monomers include the esters of monoethylenically unsaturated C3-C6 monocarboxylic acids, more particularly the esters of acrylic acid or of methacrylic acid, with C1-C20 alkanols, cycloalkanols, phenyl-Cl-C4 alkanols or phenoxy-Cl-C4 alkanols, diesters of monoethylenically unsaturated C4-C6 dicarboxylic acids with C1-C20 alkanols, cycloalkanols, phenyl-Cl-C4 alkanols or phenoxy-Cl-C4 alkanols are preferred.

Further examples of suitable monofunctional monomers include the esters of monoethylenically unsaturated C3-C6 monocarboxylic acids, more particularly the esters of acrylic acid or of methacrylic acid, with C1-C20 alkanols optionally preferred.

Further examples of suitable monofunctional monomers include the esters of acrylic acid with C2-C10 alkanols (such as C2-C10 alkyl acrylates), the esters of methacrylic acid with Cl -CIO alkanols (such as Cl -CIO alkyl methacrylates) may be preferred. Further examples of suitable monofuctional monomers include monoethylenically unsaturated C3-C8 monocarboxylic acids, such as acrylic acid, methacrylic acid, 2- butenoic acid, 3-butenoic acid, 2-acryloxyethylacetic acid and 2-methacryloxyethylacetic acid; - monoethylenically unsaturated C4-C8 monocarboxylic acids, such as maleic acid, itaconic acid and fumaric acid; the primary amides of the aforementioned monoethylenically unsaturated C3-C8 monocarboxylic acids, more particularly acrylamide and methacrylamide, the linear or branched alkyl amides of the aforementioned monoethylenically unsaturated C3-C8 monocarboxylic acids, and salts thereof, such as 2-aminoethyl (meth)acrylate hydrochloride, (meth)acryloyl-L-lysine, N- (2-aminoethyl) (meth)acrylamide hydrochloride, N-(3-aminopropyl) (meth)acrylamide hydrochloride, N-(3-BOC-aminopropyl) (meth)acrylamideN-[3-(N,N- dimethylamino)propyl] (meth)acrylamide, N-[2-(N,N-dimethylamino)ethyl] (meth)acrylamide, 2-(N,N-dimethylamino)ethyl (meth)acrylate, 2- acryloxyethyltrimethylammonium chloride, 2-diisopropylaminoethyl (meth)acrylate, 2- (tert-butylamino)ethyl (meth)acrylate; the cyclic amides of the aforementioned monoethylenically unsaturated C3-C8 monocarboxylic acids with cyclic amines, and salts thereof, such as pyrrolidine, piperidine, morpholine or piperazine, more particularly N- acryloylmorpholine,N- methacryloylmorpholine, N-acryloylmorpholine hydrochloride or N- methacryloylmorpholine hydrochloride, hydroxyalkyl esters of the aforementioned monoethylenically unsaturated C3-C8 monocarboxylic acids, e.g. hydroxy ethyl acrylate, hydroxy ethyl methacrylate, 2- and 3 -hydroxypropyl acrylate, 2- and 3 -hydroxypropyl methacrylate, monoesters of the aforementioned monoethylenically unsaturated C3-C8 monocarboxylic and C4-C8-dicarboxylic acids with C2-C4 polyalkylene glycols, more particularly the esters of these carboxylic acids with polyethylene glycol or with alkyl- polyethylene glycols, the (alkyl)polyethylene glycol radical typically having a molecular weight in the range from 100 to 5000, in particular 100 to 3000; N-vinyl amides of aliphatic Cl -CIO carboxylic acids, and N-vinyl lactams, such as N-vinylformamide, N- vinylacetamide, N-vinylpyrrolidone, and N-vinylcaprolactam. monoethylenically unsaturated sulfonic acids in which the sulfonic acid group is attached to an aliphatic hydrocarbon radical, and esters and salts thereof, such as vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 2- acrylamidoethanesulfonic acid, 2-acryloyloxyethanesulfonic acid, 2- methacryloyloxyethanesulfonic acid, 3-acryloyloxypropanesulfonic acid, 2,2- ethylhexylaminoethane sulfonic acid and 2-methacryloyloxypropanesulfonic acid, and salts thereof, monoethylenically unsaturated phosphonic acids in which the phosphonic acid group is attached to an aliphatic hydrocarbon radical, and esters and salts thereof, such as vinylphosphonic acid, 2-acrylamido-2-methylpropanephosphonic acid, 2- methacrylamido-2-methylpropanephosphonic acid, 2-acrylamidoethanephosphonic acid, 2-methacrylamidoethanephosphonic acid,, 2- acryloyloxyethanephosphonic acid, 2- methacryloyloxyethanephosphonic acid, 3- acryloyloxypropanephosphonic acid and 2- methacryloyloxypropanephosphonic acid, and salts thereof, and monoethylenically unsaturated phosphoric monoesters, more particularly the monoesters of phosphoric acid with hydroxy-C2-C4 alkyl acrylates and hydroxy- C2-C4 alkyl methacrylates, such as, for example, 2-acryloyloxy ethyl phosphate, 2-methacryloyloxy ethyl phosphate, 3- acryloyloxypropyl phosphate, 3-methacryloyloxypropyl phosphate, 4-acryloyloxybutyl phosphate and 4- methacryloyloxybutyl phosphate, and salts thereof.

Further examples of monofunctional monomers include monoethylenically unsaturated C3-C8 monocarboxylic acids, more particularly acrylic acid and methacrylic acid, the amides of the aforementioned monoethylenically unsaturated C3-C8 monocarboxylic acids, more particularly acrylamide and methacrylamide, and the hydroxyalkyl esters of the aforementioned monoethylenically unsaturated C3-C8 monocarboxylic acids, e.g. hydroxy ethyl acrylate, hydroxy ethyl methacrylate, 2- and 3-hydroxypropyl acrylate, 2- and 3-hydroxypropyl methacrylate.

Examples of combinations of monofunctional monomers include vinyl acetate and vinyl propionate, vinyl acetate and itaconic acid, vinyl acetate and di(alkyl)maleate, vinyl acetate and ethylene, or vinyl acetate and methyl (meth)acrylate. Said copolymers may be statistical or have a “blocky” distribution of the constituent monofuntional monomer units along the polymer chains.

Each multifunctional monomer may comprise any monomer which can be polymerised by a free radical mechanism. As for the monofunctional monomer(s), the term “monomer” also includes suitably reactive oligomers (typically comprising fewer than 5 repeat units), or polymers (typically comprising 5 or more repeat units).

One or more (and optionally each) of the carbon-carbon double bonds of at least one (and optionally each) multifunctional monomer may be an ethylenic carbon-carbon double bond.

At least one multifunctional monomer optionally comprises at least two (and optionally at least three) polymerisable carbon-carbon double bonds per molecule.

At least one multifunctional monomer may comprise a bifunctional monomer i.e. comprises two, and no more than two, polymerisable C-C double bonds. Examples of suitable bifunctional monomers include di(meth)acrylate or diallyl compounds, such as diacrylates and di(meth)acrylates, such as ethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate and vinyl acrylates, such as allyl (meth) acrylate, butadiene, diallyl succinate, diallyl carbonate, diallyl phthalate and substituted analogues thereof.

For example, at least one multifunctional monomer may be a trifunctional monomer i.e. comprises three, and no more than three, polymerisable C-C double bonds. Trifunctional monomers include: tripropylene glycol tri (meth) acrylate, trimethylol propane tri (meth)acrylate, pentaerythritol tri (meth)acrylate, l,3,5-triallyl-l,3,5-triazine- 2, 4, 6(1 //,3//,5//)-trione (“TTT”), or diallyl maleate.

At least one multifunctional monomer may comprise a tetrafunctional monomer which comprises four (and only four) polymerisable C-C double bonds. Examples of tetrafunctional monomers are pentaerythritol tetra (meth)acrylate.

At least one multifunctional monomer may comprise a pentafunctional monomer which comprises five (and only five) polymerisable C-C double bonds. Examples of pentafunctional monomers include: glucose penta(meth)acrylate.

At least one and preferably each multifunctional monomer is one which does not undergo hydrolysis / transesterification reactions.

The molecular mass of at least one multifunctional monomer may, for example, be more than 100, optionally more than 200, optionally more than 300, optionally less than 2000, optionally less than 1500, optionally less than 1000 and optionally less than 500g.mol '.

At least one multifunctional monomer may optionally comprise a cyclic moiety to which are attached groups comprising polymerisable carbon-carbon double bonds. Typically, each polymerisable carbon-carbon double bond will be attached, optionally via a spacer, to mutually different atoms of the cyclic moiety. The cyclic moiety may, for example, comprise a five or six membered ring. For example, the ring may comprise a 1,3,5- triazine-2,4,6-trione moiety or a benzene moiety.

The polymer may comprise residues of more than one multifunctional monomer, each multifunctional monomer comprising more than one polymerisable carbon-carbon double bond. Each multifunctional monomer may comprise the features described above in relation to multifunctional monomers. Examples of suitable combinations of multifunctional monomers include ethylene glycol di(meth)acrylate and butanediol di(meth)acrylate, ethylene glycol di(meth)acrylate and diallyl maleate, TTT and diallyl maleate, TTT and diallyl succinate, TTT and diallyl carbonate, TTT and butanediol di(meth)acrylate, TTT and ethylene glycol di(meth)acrylate.

The amount of multifunctional monomer may be at least 0.005mol%, at least 0.05mol%, at least 0.1mol%, optionally at least 0.2mol%, optionally no more than 0.4mol%, no more than 0.5mol%, no more than 0.6mol%, no more than 0.8mol%, no more than lmol%, no more than 2mol% and optionally no more than 5mol% of the monofunctional monomer content (typically based on the total content of monofunctional monomers and on the total amount of multifunctional monomers). Optionally, the amount of multifunctional monomer may be from 0.005 to lmol%, from 0.05 to 0.8mol%, from 0.1 to 0.6mol%, from 0.1 to 0.5mol%, optionally from 0.1 to 0.4mol% and optionally from 0.2 to 0.4mol% of the monofunctional monomer content (typically based on the total content of monofunctional monomers and on the total amount of multifunctional monomers).

The polymer may comprise a residue of at least one initiator. Such initiators are capable of generating free radicals. The initiator may, for example, comprise an azo initiator, such as azobis (isobutyronitrile) (AIBN), azobis (2-methylbutyronitrile) (AIVN), azobis (2,4- dimethylvaleronitrile), azobis (4-cyanovaleric acid) or a peroxide, such as hydrogen peroxide, t-butyl hydroperoxide, dilauroyl peroxide, tert-butyl peroxyneodecanoate, dibenzoyl peroxide, cumyl peroxide, tert-butyl peroxy-2-ethyl hexanoate, tert-butyl peroxy diethyl acetate and tert-butyl peroxy benzoate or a persulfate such as ammonium persulfate, sodium persulfate, potassium persulfate. The initiator may comprise a redox initiator, a photoinitiator or an oil-soluble initiator.

Examples of redox initiators may be found in US2007/0184732, in particular in paragraph [0043] Examples of photoinitiator systems may be found in US 8603730, in particular in the text bridging cols. 6 and 7.

Further examples of initiators, in particular oil-soluble initiators, may be found in US209/0258953, in particular in paragraphs [0026] to [0028]

Hydrolysis may be performed by any suitable method known to those skilled in the art and may be controlled to reach a desired degree of hydrolysis, optionally at least 60mol%, optionally at least 65mol%, optionally at least 70mol%, optionally no more than 98mol%, optionally no more than 95mol% and optionally no more than 90mol%. Optionally, the degree of hydrolysis is from 65% to 95mol% and optionally from 70% to 90mol%.

Within this application the term "hydrolysis" is understood in its broadest sense and includes base catalysed hydrolysis, saponification, acidolysis, methanolysis and transesterification. Further guidance in relation to hydrolysis may be found in “Polyvinyl alcohol developments”, Edited by C.A. Finch, (C) 1992 John Wiley & Sons Ftd, Chapter 3: Hydrolysis of Polyvinyl Acetate to Polyvinyl Alcohol, by F.F. Marten; C.W. Zvanut, p 57-77.

The polymer formed prior to hydrolysis may comprise a poly (alkenyl alkanoate), such as a poly(vinyl acetate). The polymer formed after hydrolysis may comprise a poly(alkenyl alcohol)-co-poly(alkenyl alkanoate), such as a poly(vinyl alcohol)-co-poly(vinyl acetate). The vinyl alcohol moieties may be disposed in blocks, block-like or statistically along the polymer chains, preferably the vinyl alcohol moieties comprise the block-like structure typically obtained for a methanolysis reaction.

The substrate coated may comprise a particulate, such as a seed. Further components in addition to the polymer may be included in the coating. The further components may comprise one or more of a thickener, a plasticiser, a colourant, a surfactant, a preservative, a slip agent, a defoamer and a pesticidal agent. Those further components are described below in relation to a coating composition of a second aspect of the present invention. Those further components in the use of the first aspect of the present invention may have the features described below in relation to the coating composition of the second aspect of the present invention.

In accordance with a second aspect of the present invention, there is provided a composition for forming a coating, the composition comprising a polymer comprising (C=C)-(C=C)-C=0 moieties, the polymer comprising residues of:

(i) at least one monofimctional monomer having one polymerisable double bond per molecule;

(ii) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii) at least one chain transfer agent comprising an aldehyde or ketone.

The polymer may comprise those features described above in relation to the use of the first aspect of the present invention.

The composition optionally comprises at least 5wt% said polymer, based on the total weight of the compositions, optionally at least 10wt% said polymer, optionally at least 15wt% said polymer, optionally at least 20wt% said polymer, optionally at least 25wt% said polymer, optionally at least 30wt% said polymer and optionally at least 35wt% said polymer.

The composition optionally comprises no more than 50wt% said polymer, optionally no more than 45wt% said polymer, optionally no more than 40wt% said polymer, optionally no more than 35wt% said polymer and optionally no more than 30wt% said polymer, based on the total weight of the composition.

The composition optionally comprises from 5wt% to 50wt% said polymer, based on the total weight of the composition, optionally from 10wt% to 50wt%, optionally from 20wt% to 50wt%, optionally from 20wt% to 40wt%, optionally from 30wt% to 40wt% and optionally from 30wt% to 35wt%, based on the total weight of the composition.

The polymer may be provided in solution, or may be provided as a suspension or emulsion.

The coating composition may have a viscosity at 20°C, measured using a rotary viscometer, of no more than 10 ⁵ cP, optionally no more than 5xl0 ⁴ cP and optionally no more than 10 ⁴ cP.

The coating composition may have a viscosity at 20°C, measured using a rotary viscometer, of no more than 10 ⁴ cP when the coating composition comprises at least 25wt% said polymer, based on the total weight of the coating composition, optionally at least 30wt% polymer and optionally at least 35wt% polymer, based on the total weight of the coating composition.

The coating composition may comprise one or more thickener, such as xanthan gum. The coating composition may comprise at least 0.01wt% of one or more thickener, optionally at least 0.03wt%, and optionally at least 0.05wt% of one or more thickener. The coating composition may comprise no more than 1.0wt% of one or more thickener, optionally no more than 0.5wt% and optionally no more than 0.3wt% of one or more thickener.

The coating composition may comprise one or more plasticisers. The coating composition may comprise one or more liquid plasticiser and/or one or more solid plasticiser. Examples of liquid plasticisers are alkylene glycols, such as propylene glycol and hexylene glycol. Examples of solid plasticisers are trimethylolpropane, sorbitol and urea. The coating composition may comprise at least lwt% of one or more plasticiser, optionally at least 3wt%, and optionally at least 5wt% of one or more plasticiser. The coating composition may comprise no more than 50wt% of one or more plasticiser, optionally no more than 40wt%, optionally no more than 30wt% and optionally no more than 20wt% of one or more plasticiser.

The coating composition may comprise one or more colourants. The colourant may, for example, comprise Sunsperse® Red 48:2.

The coating composition may comprise one or more surfactant, such as sodium laureth sulphate.

The coating composition may comprise a carrier liquid. The carrier liquid may be an aqueous liquid, and may therefore comprise water. The coating composition may comprise at least 15wt% carrier liquid, optionally at least 20wt% carrier liquid and optionally at least 25wt% carrier liquid, based on the total weight of the coating composition. The coating composition may comprise no more than 80wt% carrier liquid, no more than 70wt% carrier liquid, optionally no more than 60wt% carrier liquid and optionally no more than 50wt% carrier liquid.

The coating composition may be suitable for coating one or more of: packaging (for example, paper, plastics or cardboard packaging) or particulate. Such packaging may be suitable for forming a transparent coating. Such particulate may be of any suitable size, but may have a mean greatest dimension of no more than 20mm, optionally no more than 10mm, optionally no more than 5mm and optionally no more than 1 mm. Such particulate may comprise seeds.

The coating composition may comprise one or more pesticidal agent. This may be of particular use if the coating composition is for coating seeds, for example. The coating composition may comprise at least 0.1 wt% of one or more pesticidal agent, optionally at least 0.5wt%, optionally at least 1.0wt% and optionally at least 2.0wt% of one or more pesticidal agent. The coating composition may comprise no more than 20wt% of one or more pesticidal agent, optionally no more than 18wt% and optionally no more than 15wt% of one or more pesticidal agent. Such pestidical agents are discussed in paragraphs 39 to 44 of WO2014/130653, and the teaching of those paragraphs in incorporated herein by reference. For example, the one or more pesticidal agent may be selected from those listed in paragraphs 39 to 44 of WO2014/130653.

The coating composition may comprise one or more preservative, such as Kathon® CG/TP. The coating composition may comprise at least 0.01wt% of one or more preservative, optionally at least 0.03wt%, and optionally at least 0.05wt% of one or more preservative. The coating composition may comprise no more than 1.0wt% of one or more preservative, optionally no more than 0.5wt% and optionally no more than 0.3wt% of one or more preservative.

The coating composition may comprise one or more defoamer, such as Surfynol® 104PG-50. The coating composition may comprise at least 0.01wt% of one or more defoamer, optionally at least 0.03wt%, and optionally at least 0.05wt% of one or more defoamer. The coating composition may comprise no more than 1.0wt% of one or more defoamer, optionally no more than 0.5wt% and optionally no more than 0.3wt% of one or more defoamer.

The coating composition may comprise one or more slip agent, such as Michem® Lube 156P. The coating composition may comprise at least 0.01 wt% of one or more slip agent, optionally at least 0.05 wt%, and optionally at least 0.10wt% of one or more slip agent. The coating composition may comprise no more than 5.0wt% of one or more slip agent, optionally no more than 3.0wt% and optionally no more than 2.0wt% of one or more slip agent.

The coating composition may comprise one or more colourants. The presence of such colourants may alert a handler or prospective handler to the presence of pesticidal agents or the like. The colourant may, for example, comprise Sunsperse® Red 48:2.

The coating composition may be suitable for coating seeds, and therefore the coating composition may be a seed coating composition.

The coating composition may comprise one or more micronutrients, for example, one or more of sulphur, iron, zinc, molybdenum, manganese and copper. This may be of particular use, for example, if the coating composition is a seed coating composition. The coating composition may comprise one or more pH adjusting components, such as acid or alkali.

The coating composition may comprise one or more anti-herbicidal components. Such components may, for example, be of use if the coating composition is a seed coating composition. For example, the coating composition may comprise one or more anti- herbicidal component that takes-up herbicide, such as activate carbon.

The coating composition may comprise one or more water-imbibing species, such as a water-imbibing polymer.

The coating composition may comprise one or more herbicides.

In accordance with a third aspect of the present invention, there is provided a method of coating a substrate surface, the method comprising providing the surface of the substrate with a composition comprising a polymer comprising (C=C)-(C=C)-C=0 moieties, the polymer comprising residues of:

(i) at least one monofunctional monomer having one polymerisable double bond per molecule;

(ii) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii) at least one chain transfer agent comprising an aldehyde or ketone.

The composition may comprise a carrier liquid. The method may comprise removing carrier liquid from the composition. The method may comprise subjecting the substrate and/or composition to conditions for reducing the amount of carrier liquid in the composition. For example, the method may comprise heating the substrate and/or composition.

The composition may comprise one or more of the features described above in relation to the composition of the second aspect of the present invention. The polymer may comprise one or more features described above in relation to the use of the first aspect of the present invention.

The method may comprise providing a surface of the substrate with a composition in accordance with the second aspect of the present invention.

The substrate may be packaging or particulate, for example.

The method of the present invention may comprise tumbling one or more substrates in the presence of the composition. The method may comprise raising one or more substrates and allowing the one or more substrates to fall under the influence of gravity. The method may comprise using a rotatable drum.

The method of the present invention may comprise stirring one or more substrates and the composition.

The amount of composition used may vary in accordance with the nature of the substrate.

If the substrate comprises a seed, then the method of coating the substrate with the composition may comprise

The method of the present invention may provide agglomerated substrates. For example, coating of small particles, such as small seeds, may lead to agglomeration of the small particles. This may make handling of the small particles easier.

The substrate used in the method of the third aspect of the present invention may comprise those features described above in relation to the use of the first aspect of the present invention and the coating composition of the second aspect of the present invention.

In accordance with a fourth aspect of the present invention, there is provided a substrate provided with a coating, the coating comprising a polymer comprising (C=C)-(C=C)- C=0 moieties, the polymer comprising residues of:

(i) at least one monofunctional monomer having one polymerisable double bond per molecule; (ii) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii) at least one chain transfer agent comprising an aldehyde or ketone.

The polymer may have the features described above in relation to the use of the first aspect of the present invention.

The substrate may have the features described above in relation to the use of the first aspect of the present invention, the coating composition of the second aspect of the present invention and the method of the third aspect of the present invention.

The coating may comprise the components and/or features described above in relation to the use of the first aspect of the present invention and/or the coating composition of the second aspect of the present invention. The composition of the coating may be calculated based on the relative amounts of each component described above in relation to the coating composition of the second aspect of the present invention, having disregard to the carrier liquid content because the carrier liquid will generally have been removed from the coating (though it is possible that some carrier liquid may remain in the coating).

For example, if the coating composition of the second aspect of the present invention comprises 50wt% carrier liquid, then the relative amounts of the various components in the coating itself may be calculated based on the remaining 50wt% of the coating composition that is not carrier liquid.

The mean coating thickness may be at least 0.01mm, optionally at least 0.03mm, optionally at least 0.05mm, optionally at least 0.08mm and optionally at least 0.1mm.

The mean coating thickness may be no more than 1 mm, optionally no more than 0.8mm and optionally no more than 0.5mm.

The mean coating thickness may be from 0.01 to 0.5mm, optionally from 0.01 to 0.3mm, optionally from 0.01 to 0.2mm and optionally 0.01 to 0.15mm. The wt% of the coating may be at least 0.1 wt%, based on the total weight of the coating and the seed to be coated, optionally at least 0.2wt% and optionally at least 0.3wt%.

The wt% of the coating may be no more than lwt%, based on the total weight of the coating and the seed to be coated, optionally no more than 0.8wt%, optionally no more than 0.7wt% and optionally no more than 0.5wt%.

The wt% of the coating may be from 0.1 to 1 wt%, based on the total weight of the coating and the seed to be coated, optionally from 0.1 to 0.8wt%, optionally from 0.1 to 0.5wt%.

In accordance with a fifth aspect of the present invention, there is provided use of a polymer as a binder, the polymer comprising (C=C)-(C=C)-C=0 moieties, the polymer comprising residues of:

( i ) at least one monofunctional monomer having one polymerisable double bond per molecule;

( i i ) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii ) at least one chain transfer agent comprising an aldehyde or ketone.

The polymer may comprise those features and properties described above in relation to the use of the first aspect of the present invention.

The polymer may be used to bind one or more components to be bound by the binder. The use may be use as a binder in a coating or use as a binder in relation to additive manufacturing.

The one or more components to be bound by the binder may, for example, be coating components such as those described above in relation to the coating composition of the second aspect of the present invention. For example, such coating components may comprise one or more pesticidal agents. As mentioned above, the use of the polymer as a binder may be use in relation to additive manufacturing. The polymer may be used to bind a primary structure-forming component, for example. In the case of additive manufacturing, the binder may be removable, for example, by being soluble in a suitable solvent, such as an aqueous solvent.

In accordance with a sixth aspect of the present invention, there is provided a composition comprising a component to be bound and a polymer comprising (C=C)- (C=C)-C=0 moieties, the polymer comprising residues of:

( i ) at least one monofunctional monomer having one polymerisable double bond per molecule;

( i i ) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii ) at least one chain transfer agent comprising an aldehyde or ketone.

The polymer may comprise those features described above in relation to the use of the first aspect of the present invention.

The composition may comprise one or more features, and/or have one or more properties, of the coating composition described above in relation to the coating composition of the second aspect of the present invention. In such a composition, the polymer may act to bind other components of the composition, such as pestidical agent(s), for example.

The component to be bound may, for example, be a primary structure-forming component for use in additive manufacturing. The primary structure-forming component may comprise a structure-forming polymer or one or more polymerisable components capable of forming a structure-forming polymer. The structure-forming polymer may be water-insoluble, for example.

The polymer may act as a binder for the component to be bound. The composition may comprise at least 1.0wt% said polymer, based on the total weight of the composition, optionally at least 2.0wt% said polymer and optionally at least 3.0wt% said polymer. In accordance with a seventh aspect of the present invention, there is provided a binder comprising a polymer comprising (C=C)-(C=C)-C=0 moieties, the polymer comprising residues of:

(i) at least one monofunctional monomer having one polymerisable double bond per molecule;

(ii) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii) at least one chain transfer agent comprising an aldehyde or ketone.

The polymer may comprise those features described above in relation to the use of the first aspect of the present invention. The binder may be for a coating i.e. the binder may be for use as a binder in a coating.

In according with a eighth aspect of the present invention, there is provided use of a polymer in additive manufacturing, the polymer comprising (C=C)-(C=C)-C=0 moieties, the polymer comprising residues of: ( i ) at least one monofunctional monomer having one polymerisable double bond per molecule;

( i i ) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and

(iii ) at least one chain transfer agent comprising an aldehyde or ketone. The polymer may have the features described above in relation to the use of the first aspect of the present invention.

The polymer may be used as a removable support material.

In accordance with an ninth aspect of the present invention, there is provided a method of additive manufacturing, the method comprising: depositing a pre-cursor composition comprising a polymer comprising (C=C)-(C=C)- C=0 moieties, the polymer comprising residues of: ( i ) at least one monofunctional monomer having one polymerisable double bond per molecule;

( i i ) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and (iii ) at least one chain transfer agent comprising an aldehyde or ketone; and forming a hardened composition from the pre-cursor composition.

The polymer may have the features described above in relation to the use of the first aspect of the present invention. The method may comprise removing the polymer. This may be achieved, for example, using water. The method may comprise removing the polymer after forming the hardened composition from the pre-cursor composition.

In accordance with a tenth aspect of the present invention, there is provided a composition for additive manufacturing comprising a polymer comprising (C=C)-(C=C)- C=0 moieties, the polymer comprising residues of:

( i ) at least one monofunctional monomer having one polymerisable double bond per molecule;

( i i ) at least one multifunctional monomer having at least two polymerisable double bonds per molecule; and (iii ) at least one chain transfer agent comprising an aldehyde or ketone; and and a primary structure-forming component.

The polymer may have the features described above in relation to the use of the first aspect of the present invention.

The primary structure-forming component may comprise a structure-forming polymer or may comprise polymerisable components. Said structure-forming polymer is typically water-insoluble. It will, of course, be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the method of the invention may incorporate any of the features described with reference to the apparatus of the invention and vice versa. DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

Figure 1 shows how the viscosity of various aqueous compositions comprising polymers for use in examples of the present invention varies with concentration. DETAILED DESCRIPTION

Three polymers for use in the examples of the present invention were synthesised as set- out below.

Polymer 1

Methanol (102.8 kg), vinyl acetate (49 kg), TTT (0.336 kg), propanal (3.17 kg) and Peroxan PO (1.176 kg) were charged to a 500 L reactor. A nitrogen blanket was applied and the jacket temperature was set to 73 degC. After 30 minutes, an addition made up of vinyl acetate (71.6 kg), TTT (0.696 kg) and Peroxan PO (0.504 kg) and a separate addition of propanal (12.67 kg) were started and fed into the reactor over 2 hours. The jacket temperature was held for a further 2 hours before being increased to 81 degC and held for 1.5 hours. The reaction mixture was then distilled with a jacket temperature of 80-100 degC over 5 hours before cooling and adding methanol (50 kg).

Conversion was 93 % based on the total solid content of the final undistilled reaction mixture compared to the theoretical maximum total solid content reached by conversion of all monomers. The k- value was found to be 29. The polymer solution in methanol was charged to a 25 L reactor. The reaction mixture was equilibrated to 20 degC and a solution of sodium hydroxide in methanol was charged. Once the reaction was complete, the mixture was neutralised with acetic acid.

The degree of hydrolysis was 72.7 mol% and the 4 % solution viscosity was 2.79 mPa.s.

The product may optionally be dried and dissolved in water or be diluted in water as part of a distillation process, optionally to a total solid content of 20 wt% to 50 wt%.

Polymer 2

Methanol (84 kg), vinyl acetate (40 kg), TTT (0.384 kg), propanal (3.64 kg) and Peroxan PO (0.98 kg) were charged to the reactor. A nitrogen blanket was applied and the jacket temperature was set to 72 degC. After 30 minutes, an addition of vinyl acetate (59.5 kg) and a separate addition of propanal (15.4 kg) were started and fed into the reactor over 1 hour 45 minutes. A shot containing methanol (0.8 kg), TTT (0.384 kg) and Peroxan PO (0.421 kg) was added 45 minutes into the addition and a shot containing methanol (0.8 kg) and TTT (0.384 kg) was added 1 hour 15 minutes into the addition. Upon completion of the additions, the jacket temperature was held for a further 3 hours. The jacket temperature was then increased to 77 degC and held for 1 hour and then increased again to 82 degC and held for 1 hour. The reaction mixture was then distilled with a jacket temperature of 80-100 degC over 5 hours before cooling and adding methanol (40 kg). Conversion was 93 % based on the total solid content of the final undistilled reaction mixture compared to the theoretical maximum total solid content reached by conversion of all monomers. The k-value was found to be 26.

The polymer solution in methanol was charged to a 25 L reactor. The reaction mixture was equilibrated to 20 degC and a solution of sodium hydroxide in methanol was charged. Once the reaction was complete, the mixture was neutralised with acetic acid.

The degree of hydrolysis was 72.8 mol% and the 4 % solution viscosity was 2.36 mPa.s.

The product may optionally be dried and dissolved in water or be diluted in water as part of a distillation process, optionally to a total solid content of 20 wt% to 50 wt%. Polymer 3

Methanol (94.5) kg), vinyl acetate (45 kg), TTT (0.117 kg), propanal (1.8 kg) and Peroxan PO (1.1 kg) were charged to the reactor. A nitrogen blanket was applied and the jacket temperature was set to 72 degC. After 30 minutes, an addition of vinyl acetate (67 kg) and a separate addition of propanal (6.3 kg) were started and fed into the reactor over 1 hour 30 minutes. A shot containing methanol (0.9 kg), TTT (0.117 kg) and Peroxan PO (0.473 kg) was added 45 minutes into the addition and a shot containing methanol (0.9 kg) and TTT (0.117 kg) was added 1 hour 15 minutes into the addition. Upon completion of the additions, the jacket temperature was held for a further 4 hours before being increased to 82 degC and held for 1 hour. The reaction mixture was then distilled with a jacket temperature of 80-100 degC over 5 hours before cooling and adding methanol (50 kg).

Conversion was 97 % based on the total solid content of the final undistilled reaction mixture compared to the theoretical maximum total solid content reached by conversion of all monomers. The k- value was found to be 28.

The polymer solution in methanol was charged to a 25 L reactor. The reaction mixture was equilibrated to 20 degC and a solution of sodium hydroxide in methanol was charged. Once the reaction was complete, the mixture was neutralised with acetic acid.

The degree of hydrolysis was 71.1 mol% and the 4 % solution viscosity was 2.72 mPa.s.

The product may optionally be dried and dissolved in water or be diluted in water as part of a distillation process, optionally to a total solid content of 20 wt% to 50 wt%.

Viscosities of aqueous compositions of Polymers 1, 2 and 3

Aqueous compositions comprising Polymers 1, 2 and 3 were made with different amounts of polymer, and the viscosity measured using a rotary viscometer at 20°C. The results of the viscosity measurements for the aqueous compositions of Polymers 1, 2 and 3 are shown below in Tables 1, 2 and 3, respectively.

Table 1 - viscosity measurements of aqueous compositions of Polymer 1

Table 2 - viscosity measurements of aqueous compositions of Polymer 2

Table 3 - viscosity measurements of aqueous compositions of Polymer 3

The viscosities of aqueous compositions of a known, comparative polyvinyl alcohol, B72, were also measured (supplied by Synthomer (UK) Ltd., Harlow, United Kingdom).

Table 4 - viscosity measurements of aqueous compositions of comparative polymer, B72 The viscosity was measured using a Brookfield DV 1+ rotary viscometer. The solution to be tested, of known total solid content, was equilibrated in a 500 g straight edged glass jar in a water bath set to 20 °C. Once equilibrated, the sample was placed beneath the viscometer and the viscosity measured, recording also the spindle number (1-7) used, the rotational speed (in rpm) and the torque generated.

Total solid content was determined as follows:

The percentage total solids content (TSC) was determined by weighing a sample of material before and after drying in a vacuum oven at -900 to -1000 mbar and 120 °C for two hours.

Where Wi = Weight of sample container (foil dish)

W2 = Weight of container plus sample before drying W3 = Weight of container plus sample after drying

Each sample is measured in duplicate.

A labelled foil dish was weighed on a 4 place analytical balance and the weight recorded (Wi). Without taring the balance, 1 -2 g of solution was added and the weight was accurately recorded (W2). The dish was placed into a vacuum oven at 120 °C and a vacuum was pulled. After two hours the foil dishes were allowed to cool in a desiccator for 5-10 minutes and the final weight (W3) was recorded. The average TSC of two measurements was reported.

The viscosities of the aqueous compositions are shown in Fig. 1 as a function of total solid content (TSC%) of the composition (key to graph: + - B72 [conventional polymer], o - Polymer 1, A - Polymer 2, x - Polymer 3).

The compositions made using polymers 1 , 2 and 3 exhibit similar viscosities for any given wt% of polymer. Furthermore and surprisingly, the compositions for any given wt% of polymer have a far lower viscosity than a conventional polymer, B72 (Synthomer (UK) Ftd., Harlow, United Kingdom), which has been used as a coating. Perhaps more importantly, for a particular viscosity, the compositions comprising polymers 1 , 2 and 3 have a far higher polymer content that the composition comprising the conventional polymer B72. This is important because many coating apparatuses have a maximum operating viscosity, and it is advantageous to be able to have a high polymer/solids content at a particular viscosity when coating.

Such aqueous compositions comprising polymers 1, 2 and 3 may therefore effectively be used as coatings, especially when provided with other components typically used in coatings.

Coating Composition Example 1

A prophetic exemplary coating composition in accordance with the present invention was made by mixing water with Polymer 1 to give a composition that is 30% total solid content with respect to the polymer. A pesticide is added, as is a surfactant to promote dispersion of the pesticide in the water. A colourant is added to ensure that the resulting coating is coloured to indicate to potential handlers that the coating comprises a pesticide.

Coating Composition Example 2

A prophetic exemplary coating composition in accordance with the present invention was made by mixing water with Polymer 2 to give a composition that is 30% total solid content with respect to the polymer. A pesticide is added, as is a surfactant to promote dispersion of the pesticide in the water. A colourant is added to ensure that the resulting coating is coloured to indicate to potential handlers that the coating comprises a pesticide.

Coating Composition Example 3

A prophetic exemplary coating composition in accordance with the present invention was made by mixing water with Polymer 3 to give a composition that is 30% total solid content with respect to the polymer. A pesticide is added, as is a surfactant to promote dispersion of the pesticide in the water. A colourant is added to ensure that the resulting coating is coloured to indicate to potential handlers that the coating comprises a pesticide.

Those skilled in the art will realise that in Coating Composition Examples 1, 2 and 3, the pesticide is optional, as is the surfactant and the colourant. The components of the coating composition may be varied to suit the intended purpose of the coating composition. For example, if the seed coating is to have pesticidal properties, then a pesticidal agent would be included in the coating composition.

Coating Example 1

A prophetic example of a method of coating seeds in accordance with the present invention will now be described. Wheat seeds and Coating Composition Example 1 are mixed in a drum, thereby coating the seeds with the coating composition. Such seed coating drums are well-known to those skilled in the art. One such drum is described in US4465017. Such drums produce coated seeds, and provides the seed with a water- soluble protective coating. In this example, the polymer is also acting as a binder for the pesticide and colourant.

Coating Example 2

The method of Coating Example 1 was repeated using Coating Composition Example 2 instead of Coating Composition Example 1. In this example, the polymer is also acting as a binder for the pesticide and colourant.

Coating Example 3

The method of Coating Example 1 was repeated using Coating Composition Example 3 instead of Coating Composition Example 1. In this example, the polymer is also acting as a binder for the pesticide and colourant.

Binder Example

An exemplary composition in accordance with the sixth aspect of the present invention will now be described, in which Polymer Example 1 acts as a binder. The composition is an ink composition for deposition using an inkjet printer, the ink composition comprising a colourant to provide colour to the ink and polymer example 1. The polymer acts as a binder for the ink. The composition comprises about lwt% colourant and about lwt% polymer acting as binder. Additive Manufacturing Example

A prophetic example of an additive manufacturing composition comprises Polymer 1 and a non-water soluble polymer. Polymer 1 acts as a temporary support material in the additive manufacturing process, and also acts as a binder for the non-water soluble polymer. The additive manufacturing composition is used as such compositions are conventionally used, with temporary support material Polymer 1 being removed by dissolution once the temporary support material has been done away with.

Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

The examples described above relate to the coating of particulates, in particular seeds. Those skilled in the art will realise that other substrates may be coated, for example, packaging.

Those skilled in the art will realise that such coatings need not cover a whole substrate or a whole surface of a substrate.

The examples described above relate to the coating of wheat seeds. Those skilled in the art will realise that other seeds may be coated. Furthermore, in certain circumstances seeds (for example, very small seeds, such as certain flower seeds) may agglomerate or pelletise during the coating process.

Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.