The present invention relates to the field of melamine formaldehyde amino resins suitable for use in coatings, for example water borne coatings.

Melamine formaldehyde amino polymers may be produced by reacting formaldehyde with a triazine under acid or basic conditions to form a hydroxymethyl functional monomer. The functionalised monomers can then react with further triazine under acid catalyst in a polymerization step to form polymeric (or if of low molecular weight oligomeric) chains where the triazine groups are linked by methylene groups. These melamine formaldehyde polymers may be used as cross-linkers to form coating resins on a substrate. The coating is formed as a three dimensional network by reacting of the cross-linker with other suitable polymer precursors for film forming resins such as alkyds, polyesters, acrylics and epoxies.

It is desirable for coating applications io apply the resin components (such as the triazine, formaldehyde and the carboxylic acid, hydroxy, and/or (meth)acrylate monomers) to the substrate from a water dispersion and then perform all the steps in situ to form the cured cross-linked resin coat. It is also desirable for the reaction temperature to be low so that a wide variety of potentially heat sensitive substrates can be coated. However there are several factors which mitigate against this.

N. ^N

NH Conventional triazines (such as melamine) ² comprise both ring nitrogens and free amino groups which are basic when the triazine is dispersed in water. These basic groups compete to neutralize the acid catalyst in the formation of the cross-linker. A high temperature is therefore required to drive off excess amine and promote the reaction.

WO 01/60882 suggests alkoxylating the amino groups on the triazine to reduce the amount of free amino groups. The alkoxy groups are electronegative and so also reduce the basicity of the ring nitrogens. These triazines are thus much less basic and therefore the rate of neutralization of the acid catalyst is reduced and lower reaction temperatures are possible. However these triazines are not so readily dispersible with water as the comprise organic solubilising groups and so are more suitable for non aqueous systems.

It has been believed that film forming monomers comprising weakly acidic groups such as carboxylic acid and/or acidic polyols (for example acrylate monomers) were required for the coating dispersion to have good stability in water. Yet it was also believed that the presence of strong acid groups (such as sulfonate) in the dispersion would destabilize.the emulsion.

It is an object of the invention to solve some or all of the above problems with the prior art.

Broadly in accordance with the present invention there is provided a polymerisable composition comprising

(a) from about 1 % to about 95% by weight of the total composition of at least one polymer precursor for an alkyd, polyester, acrylic and/or epoxy polymer where the polymer precursor comprises a strong acid group in an amount from about 0.01 % to about 10% by weight of the polymer precursor;

(b) from about 1 % to about 95% by weight of the total composition of

(i) from about 50% to about 95% by weight of component (b) a monomeric melamine and/or derivative thereof optionally comprising less than 0.5% by weight of free amino groups; and

(ii) from about 5% to about 50% by weight of component (b) an oligomeric melamine and/or derivative thereof (optionally formed by reacting melamine and/or a derivative thereof with formaldehyde and/or derivative thereof) where the oligomer comprises less than 0.5% by weight of free amino groups.

The aforementioned polymerisable composition of the invention is usually a coating that is applied to a suitable substrate after which cross-linking / polymerisation is initiated preferably at low temperature to form a three dimensional network in situ on a subtrate.

Therefore a further aspect of the invention provides a cross-linked resin obtained or obtainable by polymerising the aforementioned polymerisable composition of the invention optionally at low temperature. Preferably the cross-linked resin comprises a coating on a substrate.

A still further aspect of the invention there is provided a method of coating a substrate optionally at low temperature comprising the steps of:

(a) coating a substrate with the aforementioned polymerisable composition of the invention; and

(b) polymerising the composition in situ optionally at low temperature to provide a cross-linked resin coating thereon.

The polymer precursor(s) of component (a) may be monomer(s) or more usually oligomer(s) or polymer(s) which are themselves polymeric and are further polymerised to form the cross-linked network. For example component (a) may comprise a

(meth)acrylic polymer functionalised with strong acid which when polymerised with the melamine cross-linkers of component (b) forms a cross-linked network also of acrylic polymer. A polymer precursor in component (a) and the polymer (cross-linked resin) formed after further polymerising the polymerisable composition are often both polymers of the same general type (i.e. alkyd, polyester, acrylic and/or epoxy).

Thus in another aspect of the present invention there is provided a process for forming a cross linked polymer network comprising the steps of

(a) obtaining a polymer (Polymer A) by polymerising a composition comprising (i) from about 1% to about 95% by weight of at least one monomer for an alkyd, polyester, acrylic and/or epoxy polymer where the monomer comprises a strong acid group in an amount from about 0.01 % to about 10% by weight of the total monomer;

(b) reacting from about 1 % to about 95% by total weight of the Polymer A from step (a) in a further polymerisation with from about 1% to about 95% by total weight of a further composition (Composition B) comprising

(i) from about 50% to about 95% by weight of the further component (b) a monomeric melamine and/or derivative thereof optionally comprising less than 0.5% by weight of free amino groups; and (ii) from about 5% to about 50% by weight of the further component (b) an oligomeric melamine and/or derivative thereof (optionally formed by reacting melamine and/or a derivative thereof with formaldehyde and/or derivative thereof) where the oligomer comprises less than 0.5% by weight of free amino groups. to form a cross-linked resin network.

Optionally in a further intermediate step (a)(ii) the Polymer A and Composition B are applied to a substrate to form a coating thereon before they are reacting in step (b) to form a cross-linked resin coating thereon.

The weights given in step (a)(i) are as a percentage of the total weight of the monomers / polymer precursors in the composition used to form Polymer A. The total weights given in step (b) are as a percentage of the combined weight of Polymer A and Composition B.

The weights given in (b)(i) & (b)(ii) are as a percentage of the amount of Composition B.

The polymer (Polymer A) obtained or obtainable in step (a) of the process of the invention forms a yet other aspect of the present invention. Polymer A may also be used as a polymer precursor in component (a) of the polymerisable composition of the invention.

Conveniently Polymer A comprises an acrylic polymer obtained from monomer comprising an activated unsaturated moiety (more conveniently of Formula 1' as described herein) functionalised with a suitable strong acid group.

As used herein the term strong acid group denotes a group which substantially completely dissociated under the conditions specified (for example in an aqueous solvent), preferred strong acid groups are those which are substantially fully ionized in water at ambient temperature.

Surprisingly the applicant has found that use of a small amount of a monomer with a strong acid group does not destabilize the monomer dispersion. There is a low concentration of (preferably substantially no) groups on the monomer(s) which are basic under the conditions of the reaction so a lower reaction temperature can be used for the acid catalysed steps.

Optionally the polymer precursor(s) comprise one or more activated unsaturated moieties, (such as one or more (meth)acrylate(s)) and/or one or more oxirane moieties.

In the process of the invention steps (a) and (b) may be simultaneous or sequential, where for example the Polymer A may be purified, collected and/or isolated before use in step (b). The steps (a) and (b) may be carried out in the same or different vessels. However it is preferred to form the melamine cross-linked resin network in situ (for examples after the components have been coated onto a suitable substrate). For example Polymer A (e.g. an acrylic polymer functionalised with strong acid) and Composition B (e.g. substantially amino free melamine cross-linker) may be made separately and coated onto a substrate (either as a pre-blended mixture or coated at the same time) and then cross-linking may be initiated at low temperature to form a cross-linked resin coating.

As used herein the term low temperature cure or cross-linking means curing the resin so polymerised is substantially complete at a temperature of less than about 100 ⁰ C.

Preferably the low temperature cure temperature is from about 30 ⁰ C to about 80 ⁰ C, more preferably from about 40 ⁰ C to about 7O ⁰ C, most preferably about 60 ⁰ C.

Preferably the curing time at these low temperatures was at least 2 minutes, more preferably from about 15 minutes to about 60 minutes, most preferably from about 20 minutes to about 40 minutes for example about 30 minutes.

The polymer precursors for use as component (a) in the composition and/or process of the invention may comprise those of Formula 'I'

° ² Formula T where

L is a divalent organo linking group, optionally hydrocarbo, more optionally hydrocarbylene;

Q ₁ is a strong acid group; Q ₂ is a suitable counter ion; and n= 0 or 1 (i.e. Formula I represents a methacrylate, when n is 1 , or an acrylate, when n is O).

Preferred monomers of Formula I may be represented by Formula Ia

Formula 'Ia' where m = 1 to 18 (i.e. in Formula I, L is Ci.iβalkylene) and n is 0 or 1.

In Formula I and Formula Ia Q ₁ may be any suitable strongly acidic cationic or anionic group and may be attached at any point along the chain.

Formula I are those represented by Formula 'Ib'

Formula 'Ib' where

Q ₁ may be a protonated optionally substituted amine (in which case Q ₂ is any suitable anion such as halide); or Q ₁ may be the anion of a suitable strong acid such as a phosphonate or sulfonate group (in which case Q ₂ is any suitable cation such as an alkali metal ion).

Thus Formula Ib corresponds to methacrylate monomers of Formula I where L is propylene and monomers of Formula Ia where m is 3 and n is 1. Most preferred monomers are selected from

= SPMK or potassium salt of sulfopropylmethacrylate

and where A ^" is any suitable counter anion.

Preferred triazines suitable for use in the present invention comprise those described and/or claimed in WO 01/60882 such as Examples 2 or 3 therein. Other preferred triazines which can be used as described herein are those commercially available triazines used to prepare highly alkylated melamine formaldehyde resins, such as hexa methoxy methyl melamine (denoted herein as HMMM and having structure

e melamine of structure:

and/or any mixtures thereof.

Preferably the compositions of the invention are dispersed in water.

A further aspect of the present invention provides polymers and/or oligomers obtained and/or obtainable by polymerizing an aqueous dispersion of a compositions of the invention described above optionally in the presence of an acid catalyst.

Preferred oligomers and/or polymers of the invention have a weight average molecular weight (Mw) of from about 10,000 to about 500,000 daltons, more preferably from about 10,000 to about 100,000 daltons.

Further explanation and definitions for the some of the chemical and other terms used herein is provided below. However as the context dictates there may be a conflict between either the whole or a part of the present application the detailed example shall prevail unless there is clearly an error in the present application.

As used herein plural forms of the terms herein are to be construed as including the singular form and vice versa.

The term "comprising" as used herein will be understood to mean that the list following is non-exhaustive and may or may not include any other additional suitable items, for example one or more further feature(s), component(s), ingredient(s) and/or substituent(s) as appropriate.

The terms 'effective', 'acceptable' 'active' and/or 'suitable' (for example with reference to any process, use, method, application, preparation, product, material, formulation, compound, monomer, oligomer, polymer precursor, and/or polymers of the invention and/or described herein as appropriate) will be understood to refer to those features of the invention which if used in the correct manner provide the required properties to that which they are added and/or incorporated to be of utility as described herein.

Such utility may be direct, for example where a material has the required properties for the any of the uses described and/or indirect for example where a material has use as a synthetic intermediate and/or diagnostic tool in preparing other materials of direct utility. As used herein these terms also denote that a functional group is compatible with producing effective, acceptable, active and/or suitable end products.

Many of the definitions described in this disclosure may be based on those given by IUPAC whose definitions are also incorporated herein by reference.

The terms Optional substituent' and/or Optionally substituted' as used herein (unless followed by a list of other substituents) signifies one or more of the following groups (or substitution by these groups): carboxy, sulfo, formyl, hydroxy, amino, imino, nitrilo,

mercapto, cyano, nitro, methyl, methoxy and/or combinations thereof. These optional groups include all suitable chemically possible combinations in the same moiety of a plurality (preferably two) of the aforementioned groups (e.g. amino and sulfonyl if directly attached to each other represent a sulfamoyl group). Preferred optional substituents comprise: carboxy, sulfo, hydroxy, amino, mercapto, cyano, methyl, halo, trihalomethyl and/or methoxy.

The synonymous terms Organic substituent' and "organic group" as used herein (also abbreviated herein to "organo") denote any univalent or multivalent moiety (optionally attached to one or more other moieties) which comprises one or more carbon atoms and optionally one or more other heteroatoms.

Organic groups may comprise organoheteryl groups (also known as orgaπoelement groups) which comprise univalent groups containing carbon, which are thus organic, but which have their free valence at an atom other than carbon. Specific subclasses of organoheteryl groups comprise organothio (or organylthio) and organogermanium (or organylgermanium). Examples of organoheteryl groups are. phenoxy, acetamido, pyridinio (C ₅ H ₅ N ⁺ -), thiocyanato (N≡C-S-), trimethyl and silyl.

Organic groups may alternatively or additionally comprise organyl groups which comprise any organic substituent group, regardless of functional type, having one free valence at a carbon atom.

Organic groups may also comprise heterocyclyl groups which comprise univalent groups formed by removing a hydrogen atom from any ring atom of a heterocyclic compound: (a cyclic compound having as ring members atoms of at least two different elements, in this case one being carbon).

Organoheteryl (or organoelement) groups denotes univalent groups comprising carbon, which are thus organic, but which have their free valence at an atom other than carbon.

Specific subclasses of organoheteryl groups comprise organothio (or organylthio) and organogermanium (or organylgermanium). Examples of organoheteryl groups are. phenoxy, acetamido, pyridinio (C ₅ H ₅ N ⁺ -), thiocyanato (N≡C-S-), trimethyl and silyl.

Groups such as hydroxyphenyl and aminoacetyl are not organoheteryl groups as the free valence is at a carbon atom.

Organyl groups are any organic substituent group, regardless of functional type, having one free valence at a carbon atom for example CH ₃ CH ₂ - , CICH ₂ - , CH ₃ C(=O)-, 4-pyridylmethyl. Organyl may also be used in conjunction with other terms, as in organylthio- (e.g. MeS-) and organyloxy.

Oxo compounds comprise an oxygen atom, =0, doubly bonded to carbon or another element. The term thus embraces aldehydes, carboxylic acids, ketones, sulfonic acids, amides and esters. Oxo can be used herein as an adjective (and thus separated by a space) modifying another class of compound, as in oxo carboxylic acids or can indicate the presence of an oxo substituent at any position. To indicate a double-bonded oxygen that is part of a ketonic structure, the term keto may also be used as a prefix.

Keto may also be used to denote oxidation of CHOH to C=O in a parent compound that contains OH groups (such as carbohydrates) as in 3-ketoglucose; ketoaldonic acids; and ketoaldoses.

Organoheteryl (or organoelement) groups denotes univalent groups comprising carbon, which are thus organic, but which have their free valence at an atom other than carbon. Specific subclasses of organoheteryl groups comprise organothio (or organylthio) and organogermanium (or organylgermanium). Examples of organoheteryl groups are. phenoxy, acetamido, pyridinio (C ₅ H ₅ N ⁺ -), thiocyanato N=C-S-), trimethyl and silyl. Groups such as hydroxyphenyl and aminoacetyl are not organoheteryl groups as the free valence is at a carbon atom.

Organyl groups are any organic substituent group, regardless of functional type, having one free valence at a carbon atom for example CH ₃ CH ₂ - , CICH ₂ - , CH ₃ C(=O)-, 4-pyridylmethyl. Organyl may also be used in conjunction with other terms, as in organylthio- (e.g. MeS-) and organyloxy.

The term oxirane denotes an optionally substituted, saturated ring of up to eight, more preferably from 3 to 6 atoms, in which an oxygen atom is one of the ring atoms, the other ring atoms being carbon. More preferred oxiranes comprise optionally substituted three (epoxy) or four (oxetanyl) membered rings.

Preferably the non carbon atoms in an organic group may be selected from: hydrogen, halo, phosphorus, nitrogen, oxygen, silicon and/or sulphur, more preferably from hydrogen, nitrogen, oxygen, phosphorus and/or sulphur, most preferably from hydrogen, nitrogen and/or oxygen.

Most preferred organic groups comprise one or more of the following carbon containing moieties: alkyl, alkoxy, alkanoyl, carboxy, carbonyl, formyl and/or combinations thereof; optionally in combination with one or more of the following heteroatom containing moieties: oxy, thio, sulfinyl, sulfonyl, amino, imino, nitrilo and/or combinations thereof. Organic groups include all chemically possible combinations in the same moiety of a plurality (preferably two) of the aforementioned carbon containing and/or heteroatom

moieties (e.g. alkoxy and carbonyl if directly attached to each other represent an alkoxycarbonyl group).

The term 'hydrocarbo group ¹ as used herein is a sub-set of an organic group and denotes any univalent or multivalent moiety (optionally attached to one or more other moieties) which consists of one or more hydrogen atoms and one or more carbon atoms and may comprise one or more saturated, unsaturated and/or aromatic moieties.

Hydrocarbo groups may comprise one or more of the following groups.

Hydrocarbyl groups comprise univalent groups formed by removing a hydrogen atom from a hydrocarbon (for example alkyl, ethyl and phenyl).

Hydrocarbylene groups comprise divalent groups formed by removing two hydrogen atoms from a hydrocarbon, the free valencies of which are not engaged in a double bond (for example alkylene,. 1 ,3-phenylene, -CH ₂ CH ₂ CH ₂ - propane-1 ,3-diyl, -CH ₂ - and methylene).

Hydrocarbylidene groups comprise divalent groups (which may be represented by "R ₂ C=") formed by removing two hydrogen atoms from the same carbon atom of a hydrocarbon, the free valencies of which are engaged in a double bond (for example alkylidene).

Hydrocarbylidyne groups comprise trivalent groups (which may be represented by "RC=') formed by removing three hydrogen atoms from the same carbon atom of a hydrocarbon the free valencies of which are engaged in a triple bond (for example alkylidyne).

Hydrocarbo groups may also comprise saturated carbon to carbon single bonds (e.g. in alkyl groups); unsaturated double and/or triple carbon to carbon bonds (e.g. in respectively alkenyl and alkynyl groups); aromatic groups (e.g. in aryl groups) and/or combinations thereof within the same moiety and where indicated may be substituted with other functional groups

The term 'alkyl ¹ or its equivalent (e.g. 'alk') as used herein may be readily replaced, where appropriate and unless the context clearly indicates otherwise, by terms encompassing any other hydrocarbo group such as those described above (e.g. comprising double bonds, triple bonds, aromatic moieties (such as respectively alkenyl, alkynyl and/or aryl) and/or combinations thereof (e.g. aralkyl) as well as any multivalent

hydrocarbo species linking two or more moieties (such as bivalent hydrocarbylene radicals e.g. alkylene).

Any radical group or moiety mentioned herein (e.g. as a substituent) may be a multivalent or a monovalent radical unless otherwise stated or the context clearly indicates otherwise (e.g. a bivalent hydrocarbylene moiety linking two other moieties). However where indicated herein such monovalent or multivalent groups may still also comprise optional substituents. A group which comprises a chain of three or more atoms signifies a group in which the chain wholly or in part may be linear, branched and/or form a ring (including spiro and/or fused rings). The total number of certain atoms may be specified for certain substituents for example Ci. _N organo, signifies a organo moiety comprising from 1 to N carbon atoms. In any of the formulae that may be disclosed herein if one or more substituents are not indicated as attached to any particular atom in a moiety (e.g. on a particular position along a chain and/or ring) the substituent may replace any H and/or may be located at any available position on the moiety which is chemically suitable and/or effective.

Preferably any of the organo groups listed herein comprise from 1 to 36 carbon atoms, more preferably from 1 to 18 carbon atoms. It is particularly preferred that the number of carbon atoms in an organo group is from 1 to 12, especially from 1 to 10 inclusive, for example from 1 to 4 carbon atoms.

As used herein chemical terms (other than IUAPC names for specifically identified compounds) which comprise features which are given in parentheses - such as (alkyl)acrylate, (meth)acrylate and/or (co)polymer - denote that that part in parentheses is optional as the context dictates, so for example the term (meth)acrylate denotes both methacrylate and acrylate.

The substituents on the repeating unit of a polymer and/or oligomer may be selected to improve the compatibility of the materials with the polymers and/or resins in which they may be formulated and/or incorporated for the uses described herein. Thus the size and length of the substituents may be selected to optimise the physical entanglement or interlocation with the resin or they may or may not comprise other reactive entities capable of chemically reacting and/or cross-linking with such other resins as appropriate.

Certain moieties, species, groups, repeat units, compounds, oligomers, polymers, materials, mixtures, compositions and/or formulations which comprise and/or are used in some or all of an invention as described herein may exist as one or more different forms such as any of those in the following non exhaustive list: stereoisomers (such as

enantiomers (e.g. E and/or Z forms), diastereoisomers and/or geometric isomers); tautomers (e.g. keto and/or enol forms);conformers; salts; zwitterions; complexes (such as chelates, clathrates, crown compounds, cyptands / cryptades, inclusion compounds, intercalation compounds, interstitial compounds, ligand complexes, organometallic complexes, non-stoichiometric complexes, π-adducts, solvates and/or hydrates); isotopically substituted forms; polymeric configurations [such as homo or copolymers, random, graft and/or block polymers, linear and/or branched polymers (e.g. star and/or side branched), cross-linked and/or networked polymers, polymers obtainable from di and/or tri-valent repeat units, dendrimers, polymers of different tacticity (e.g. isotactic, syndiotactic or atactic polymers)]; polymorphs (such as interstitial forms, crystalline forms and/or amorphous forms); different phases, solid solutions; and/or combinations thereof; and/or each and all mixtures of the each and all of above forms where possible and/or suitable.

Any invention described herein comprises and/or uses all such forms which are effective as defined in this disclosure.

Where appropriate compounds of and/or used in an invention and/or described herein may be reacted with one or more organic or inorganic acid or base (as appropriate) to form one or more salts effective in one or more of any uses described herein. Thus such compounds may form salts with organic or inorganic acids (for example acid addition salts). It will be appreciated that such salts provided they are acceptable may be used in place of their corresponding compounds. Such salts may be prepared by reacting corresponding compounds with a suitable acid or base in a conventional manner.

Certain compounds of an invention may exist in more than one physical form (for example different crystal forms) and an invention includes each physical form (for example each crystal form) of compounds of formula I and mixtures thereof.

Certain compounds of an invention may also exist in the form of solvates (for example hydrates) or as an unsolvated form (for example an anhydrous form) and an invention includes each solvate of compounds of an invention and mixtures thereof. The degree of solvation may be non-stoichiometric. If the solvent is water the hydrate may be, for example, a hemihydrate, a monohydrate or a dihydrate.

It will be appreciated by those skilled in the art that certain compounds described herein may contain one or more chiral centre or centres and exist in different optically active forms. Thus, for example, certain compounds may contain a chiral centre at an asymmetrically substituted carbon atom. When a compound contains a single chiral

centre it may exist in two enantiomeric forms. Unless the context dictates otherwise an invention includes all and each enantiomer of such compounds and any mixtures thereof whether or not racemic (equal amounts of both enantiomer). Enantiomers may be obtained by methods known to those skilled in the art. Such methods typically include one or more of any of the following: resolution via formation of diastereoisomeric salts or complexes which may be separated, for example, by crystallisation; formation of diastereoisomeric derivatives or complexes which may be separated (for example, by crystallisation, gas-liquid or liquid chromatography), followed by the liberation of the desired enantiomer from the separated derivative; selective derivatisation of one enantiomer by reaction with an enantiomer-specific reagent (for example enzymatic esterification, oxidation or reduction), followed by separation of the modified and unmodified enantiomers; use of gas-liquid or liquid chromatography in a chiral environment (for example on a chiral support such as silica gel with a bound chiral ligand and/or in the presence of a chiral solvent); asymmetric synthesis of a specific enantiomer using optically active reagents, substrates, catalysts, solvents and/or enzymatic processes; and asymmetric transformation of one enantiomer into the other.

When compounds contain more than one chiral centre they may exist in diastereoisomeric forms. The diastereoisomers may be separated by methods known to those skilled in the art, for example by chromatography or crystallisation and individual enantiomers within the diastereoisomers may be separated as described above. An invention includes each diastereoisomer of such compounds and mixtures thereof.

It will be appreciated that where the active moiety is transformed by the separation procedures described above, a further step may be required to convert the transformation product back to the active moiety.

Certain compounds described herein may exist in different tautomeric forms or as different geometric isomers, and the present invention includes each tautomer and/or geometric isomer of compounds of the invention and mixtures thereof.

Certain compounds described herein may exist in different stable conformational forms which may be isolatable and/or separable. For example rings may exist in more than one stable conformation or there may be torsional asymmetry due to restricted rotation about an asymmetric single bond, and thus steric hindrance and/or ring strain, may permit separation of different conformers. An invention includes each conformational isomer of such compounds and mixtures thereof.

Certain compounds described herein may exist in zwitterionic form and an invention includes each zwitterionic form of compounds of formula I and mixtures thereof.

In certain documents the term "activated unsaturated moiety" may be used to denote an species comprising at least one unsaturated carbon to carbon double bond in chemical proximity to at least one activating moiety. Preferably the activating moiety comprises any group which activates an ethylenically unsaturated double bond for addition thereon by a suitable electrophillic group. Conveniently the activating moiety comprises oxy, thio, (optionally organo substituted)amino, thiocarbonyi and/or carbonyl groups (the latter two groups optionally substituted by thio, oxy or (optionally organo substituted) amino). More convenient activating moieties are (thio)ether, (thio)ester and/or (thio)amide moiet(ies). Most convenient "activated unsaturated moieties" comprise an "unsaturated ester moiety" which denotes an organo species comprising one or more "hydrocarbylidenyl(thio)carbonyl(thio)oxy" and/or one or more "hydrocarbylidenyl(thio)- carbonyl(organo)amino" groups and/or analogous and/or derived moieties for example moieties comprising (meth)acrylate functionalities and/or derivatives thereof. "Unsaturated ester moieties" may optionally comprise optionally substituted generic α,β-unsaturated acids, esters and/or other derivatives thereof including thio derivatives and analogs thereof.

Preferred activated unsaturated moieties are those represented by the following formula.

Formula 1' where n ¹ is O or 1 ,

X' ¹ is oxy or, thio

X' ² is oxy, thio or NR' ₅ (where R' ₅ represents H or optionally substituted organo),

R'i, R' _2, R ^* ₃ and R' ₄ each independently represent H, optionally substituents and/or optionally substituted organo groups; and all suitable isomers thereof, combinations thereof on the same species and/or mixtures thereof.

In will be appreciated that the terms "activated ^* unsaturated moiety"; "unsaturated ester moiety" and/or the above formula may represent a discrete chemical species (such as

a compound, ion, free radical, oligomer and/or polymer) and/or any part(s) thereof. Thus the above formula may also represent multivalent (preferably divalent) radicals. Thus the options given herein for n', X' ¹ , X' ² , R ¹ ,, R' ₂ , R' ₃ , R' ₄ and RV also encompass corresponding bi or multivalent radicals as appropriate.

More preferred moieties of this formula (including isomers and mixtures thereof) are those where n' is 1 ; X' ¹ is O; X' ² is O, S or NR' ₅ ;

R'i, R' ₂ , R ^* ₃ , and 'R ₄ are independently selected from: H, optional substituents and optionally substituted C^ohydrocarbo, and where present R' ₅ is selected from H and optionally substituted C _1-10 hydrocarbo.

Most preferably n' is 1 , X' ¹ is O; X' ² is O or S and R'i, R' ₂ , R' ₃ and R' ₄ are independently H, hydroxy and/or optionally substituted Ci ₆ hydrocarbyl. For example n' may be 1 , X' ¹ and X' ² may both be O:and R' ₂ may be H and R' ₃ may be H or CH ₃ .

More conveniently moieties of this formula are those where n' is 1; X' ¹ and X' ² are both O; R' _I is OH, R' ₂ is CH ₃ , and R' ₃ is H, and/or tautomer(s) thereof (for example of an acetoacetoxy functional species).

Most convenient unsaturated ester moieties are selected from: -OCO-CH=CH ₂ ; -OCO-C(CHa)=CH ₂ ; acetoacetoxy, -OCOCH=C(CH ₃ )(OH) and all suitable tautomer(s) thereof.

It will be appreciated that any suitable moieties represented by this formula might be used in the context of an invention such as other reactive moieties.

Many other variations embodiments of the invention will be apparent to those skilled in the art and such variations are contemplated within the broad scope of the present invention.

Further aspects of the invention and preferred features thereof are given in the claims herein.

Examples

The present invention will now be described in detail with reference to the following non limiting example which are by way of illustration only. In the examples and description herein the following abbreviations have been used for the various materials used:

BA = butyl acrylate,

DDM = dodecyl mercaptan (chain transfer agent)

HEA= hydroxyethyl acrylate,

HEMA = Hydroxyethyl methacrylate

MA = methyl acrylate

AA = acrylic acid

HBA = hydroxybutyl acrylate i-BMA = isobutylmethacrylate

MAA = methacrylic acid

MMA = methyl methacrylate;

PnP = n-propyl ether of propylene glycols (blend of 1-propoxy-2-proponal and 2- propoxy-1 -propanol) available commercially from Dow as a coalescing aid.

PTSA = para toluene sulfonic acid, an acid catalyst available commercially from King

Industries under the trade designation KC-1040

SPMK = Potassium salt of sulfopropylmethacrylate or ST = styrene

Examples 1 to 3 & Comp A acrylic copolymers

In Table 1 various acrylic polymers were prepared which were then formulated with melamine resins and were attempted to cure to form a three dimensional network. In each of these examples the chain transfer agent DDM was used in an amount of 0.5%.

Examples 1 to 3 exemplify Polymer A as described herein as the copolymer is functionalised with a strong acid group (sulpho). Comp A is a conventional acrylic copolymer.

Table 1

Resin SPMK MAA/AA ¹ HEA/HEMA ² BA HBA i-BMA MMA ST

Ex 1 0.6 4.8 7.5 35.1 46.6 5.3

Ex 2 0.6 6.3 11.0 31.3 45.6 5.2

Ex 3 0.6 6.3 7.4 34.9 45.6 5.2

Comp A - 4.8 ¹ 6.0 ² 21.9 14.9 18.2 34.3

¹ Contains AA in composition ² Contains HEMA in composition

Examples 4 to 6 melamine formaldehyde type resins (low temperature cure)

The acrylic copolymers with strong acid groups (Examples 1 to 3) were mixed with suitable melamine formaldehyde resin crosslinkers in the proportions shown in Table 2 (given as weight ratios).

Table 2

Ex 4 Ex 5 Ex 6

Melamine Formaldehyde cross- 10 10 10 linker, (100 % solids) (74 equivalent weight) PnP Co-solvent 20.0 20.0 20.0 Resin (-37.5% solids) at 80 w/w Ex 1 Ex 2 Ex 3

Each of these resins was mixed with melamine crosslinker resin in the weight ratio 75 resin to 25 melamine. The mixtures were further mixed by hand and roller for 5 minutes and no further change was observed.

Then the PTSA catalyst was added (KC-1040 from King) in a single amount of 3.0 by weight ratio to the amounts in Table 2.

The catalyzed mixture with Ex 4, 5, and 6 were applied conventionally to as a drawdown to a steel panel to form wet film thereon of 6 mil thickness, from which solvent was flashed off over 10 minutes. The coated samples were then allowed to cure at 60 ⁰ C for 30 minutes and then removed from the oven. The samples were left for four hours and then the Persoz hardness (measured conventionally) were to be in the range of 90 to 120 sec. The samples were left at ambient temperature that the Persoz hardness were in the range of 170 to 200 seconds. The samples were then double rubbed with methyl ethyl ketone (MEK) in a conventional test and found to resist

> 200 double rubs.

Comp B Control Experiment The acrylic polymer in Comp A was mixed with melamine formaldehyde crosslinker to attempt to form cross-linked melamine formaldehyde resin in the proportions shown in

Table 3 (given as weight ratio).

Table 3

Melamine Formaldehyde Cross- 10 linker(100% Solids)(74 equivalent weight)

PnP Co-solvent 20.0

Resin(~37.5% solids) at 80 w/w Comp A

The resin was mixed with melamine resin crosslinker in the weight ratio 75 resin to 25 melamine. The PTSA catalyst was added (KC-1040 from King) in a single amount of 3.0 by weight ratio to the amount in Table 3. The catalyzed mixture with Comp B was applied conventionally to as a drawdown to a steel panel to form wet film thereon of 6 mil thickness, from which solvent was flashed off over 10 minutes. The coated sample was then allowed to cure at 60°C for 30 minutes and then removed from the oven. The sample was left at ambient temperature for 4 days after which the Persoz hardness was only 14 sec. The sample was then double rubbed with methyl ethyl ketone (MEK) in a conventional test and found to be only 2 double rubs.