Composition

INTRODUCTION

The present invention relates to an antifouling coating composition comprising a silyl (meth)acrylate polymer, tralopyril and a polar solvent, as well as to a method of preparing the composition. The composition has excellent long term storage stability. The invention also relates to paint comprising the composition and to a paint container containing the composition. Additionally the invention relates to an article comprising a coating on at least a part of a surface thereof and to a method of coating an article to prevent fouling thereon comprising coating at least a part of a surface of the article with the composition.

BACKGROUND

Surfaces that are submerged in the marine environment are subject to the attachment of fouling organisms, such as bacteria, diatoms, algae, tube worms, barnacles and mussels. Of all the marine organisms that grow on the surfaces, hard fouling (such as barnacles, mussels and tubeworms) is the problem that leads to the highest economic consequences. Given the right conditions, hard fouling can grow extremely quickly. Barnacles and mussels are distributed worldwide and are the most commonly encountered fouling organism in coastal waters.

The risk of fouling and the attachment of barnacles and other hard fouling on vessels is typically highest during outfitting periods for new buildings and on vessels having a long layup at anchorage or a long static period during trading. Fouling can seriously impair the operational efficiency of a vessel. It causes increased hydrodynamic drag resulting in increased fuel consumption, decreased speed and decreased operational range. A very rough fouled hull can increase fuel usage by as much as 40 %. There are also additional expenses of dry-docking. The removal of attached calcareous organisms such as barnacles, mussels and tubeworms has to be done by mechanical scraping. Fouling on vessels can also cause the spread of non- indigenous species. These are all important economic factors that demand the prevention of biofouling.

To prevent settlement and growth of marine organisms antifouling paints are used. These paints generally comprise polymers which form a film (sometimes referred to as film-forming binder), antifouling agents which deter or control the fouling, pigments and solvents. In many cases the paint also comprises one or more further compounds such as extenders, dehydrating agents and thixotropic agents. Tralopyril is an antifouling agent having a broad-spectrum activity against hard- shelled and soft bodied animal organisms. It is therefore an attractive antifouling agent to incorporate into paint and especially paint designed for application to surfaces of submerged vessels such as ships.

A problem encountered with the inclusion of tralopyril in paints, however, is that when it is combined with silyl (meth)acrylate polymer, the paint tends to thicken or even gel during storage and particularly during storage for >1 month, e.g. 6 months. In other words paints comprising silyl (meth)acrylate polymer and tralopyril tend to increase in viscosity during storage indicating that reactions are happening in the paint and it is not entirely stable. This is obviously a practical problem. The viscosity of paint determines how it can be applied (e.g. whether it can be sprayed) and also impacts on the surface finish. For industrial paint, such as antifouling paint, the paint is typically applied to very large surface areas and is most often applied by airless spray. The viscosity of the paint must therefore be in a range that enables application by state of the art equipment. A paint cannot be thinned and sprayed if it has gelled.

EP-A-3078715 recognises the stability problem encountered in paints comprising silyl (meth)acrylates and tralopyril. It confirms that such paints have a tendency to thicken during storage. EP-A-3078715 goes on to disclose that the problem can be overcome by the addition of a stabiliser selected from carbodiimides and/or silanes.

SUMMARY OF THE INVENTION

Viewed from a first aspect the present invention provides an antifouling composition comprising:

(i) a silyl (meth)acrylate polymer;

(ii) tralopyril;

(iii) a polar solvent; and

(iv) a non-polar solvent;

wherein said polar solvent has an evaporation rate relative to n-butyl acetate of at least 0.1 and a Hansen solubility parameter, δΗ of <17.0 (J/cm ³ ) ¹ ' ² , said composition comprises at least 2.5 wt% polar solvent, based on the total amount of solvent present in the composition, and said composition has a viscosity of less than 2000 cP.

Viewed from a further aspect the present invention provides a method for preparing a composition as hereinbefore described comprising mixing:

(i) a silyl (meth)acrylate polymer; (ii) tralopyril;

(iii) a polar solvent; and

(iv) a non-polar solvent.

Viewed from a further aspect the present invention provides a paint comprising a composition as hereinbefore described.

Viewed from a further aspect the present invention provides a paint container containing a composition as hereinbefore described.

Viewed from a further aspect the present invention provides an article comprising (e.g. covered with or coated with) a coating on at least a part of a surface thereof, wherein said coating comprises the composition as hereinbefore described.

Viewed from a further aspect the present invention provides a method of coating an article to prevent fouling thereon, wherein said method comprises:

coating at least a part of a surface of said article with a composition as hereinbefore described; and drying and/or curing said coating.

Viewed from a further aspect the present invention provides the use of a composition as hereinbefore described for coating at least a part of a surface of an article to prevent fouling thereon.

DEFINITIONS

As used herein the term "antifouling coating composition" refers to a composition that, when applied to a surface, prevents or minimises growth of marine organisms on a surface.

As used herein the term "paint" refers to a composition comprising the antifouling coating composition as herein described and optionally solvent which is ready for use, e.g. for spraying. Thus the antifouling coating composition may itself be a paint or the antifouling coating composition may be a concentrate to which solvent is added to produce a paint.

As used herein the term Hansen solubility parameter, δΗ, provides a measure of the hydrogen bonds between molecules in a solvent.

As used herein the term Hansen solubility parameter, δϋ, provides a measure of the dispersion forces between molecules in a solvent.

As used herein the term Hansen solubility parameter, δΡ, provides a measure of the dipolar intermolecular forces between molecules in a solvent.

All Hansen solubility parameters quoted herein are from HSPiP (Hansen Solubility Parameters in Practice) software, 4th Edition 4.1 .07. As used herein the term "silyl (meth)acrylate polymer" refers to a polymer comprising repeat units derived from silyl (meth)acrylate monomers. Generally a silyl (meth)acrylate polymer will comprise at least 5 wt%, more preferably at least 20 wt% and still more preferably at least 40 wt% repeat units derived from silyl (meth)acrylate monomers, i.e. silyl acrylate and/or silyl methacrylate monomers.

As used herein the term "alkyl" refers to saturated, straight chained, branched or cyclic groups. Alkyl groups may be substituted or unsubstituted.

As used herein the term "cycloalkyl" refers to a saturated or partially saturated mono- or bicyclic alkyl ring system containing 3 to 10 carbon atoms. Cycloalkyl groups may be substituted or unsubstituted.

As used herein the term "alkylene" refers to a bivalent alkyl group.

As used herein the term "aryl" refers to a group comprising at least one aromatic ring. The term aryl encompasses heteroaryl as well as fused ring systems wherein one or more aromatic ring is fused to a cycloalkyl ring. Aryl groups may be substituted or unsubstituted. An example of an aryl group is phenyl, i.e. C ₆ H ₅ . Phenyl groups may be substituted or unsubstituted.

As used herein the term "substituted" refers to a group wherein one or more, for example up to 6, more especially 1 , 2, 3, 4, 5 or 6, of the hydrogen atoms in the group are replaced independently of each other by the corresponding number of the described substituents. The term "optionally substituted" as used herein means substituted or unsubstituted.

As used herein the term "molecular weight" refers to weight average molecular weight (Mw), unless otherwise specified.

As used herein the term "PDI" or polymer dispersity index refers to the ratio Mw/Mn, wherein Mn refers to number average molecular weight.

As used herein the term "volatile organic compound (VOC)" refers to a compound having a boiling point of 250 °C or less at a standard atmospheric pressure of 101 .3 kPa.

As used herein the term "rosin" refers to rosin and rosin derivatives.

As used herein "antifouling agent" refers to a compound or mixture of compounds that prevents the settlement of marine organisms on a surface, and/or prevents the growth of marine organisms on a surface and/or encourages the dislodgement of marine organisms from a surface.

As used herein the term "extender" is used interchangeably with "filler" and refers to a compound which increases the volume or bulk of a coating composition. DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an antifouling coating composition comprising:

(i) a silyl (meth)acrylate polymer;

(ii) tralopyril;

(iii) a polar solvent; and

(iv) a non-polar solvent.

Optionally the composition further comprises one or more of: (v) additional antifouling agent; (vi) carboxylic acid compound and/or derivative thereof; (vii) a binder; (viii) a pigment and/or extender; (ix) a dehydrating agent; and (x) an additive.

In the antifouling coating compositions of the present invention the combination of a silyl (meth)acrylate polymer, tralopyril and polar solvent advantageously provides a composition which has long term storage stability as well as excellent application properties. This means that the antifouling coating composition can be stored for an extended period of time (e.g. at least 1 month in uncontrolled temperature conditions) and still have a viscosity of less than 2000 cP which enables it to be applied to a surface, e.g. by spraying. The polar solvent may replace some or all of the conventional solvents (e.g. aromatic hydrocarbon solvents) present in antifouling coating compositions. Preferably, however, the antifouling coating composition comprises a non-polar solvent.

Polar Solvent

The polar solvent present in the antifouling coating composition preferably has an evaporation rate relative to n-butyl acetate of at least 0.15. Preferably the polar solvent has an evaporation rate relative to n-butyl acetate of 0.15 to 5.0, more preferably 0.2 to 2.5 and still more preferably 0.3 to 2.0. Preferably the evaporation rate is determined according to ASTM D3539 in an evaporometer at a temperature of 25 °C and at a relative humidity below 5 %.

The polar solvent present in the antifouling coating composition preferably has a Hansen solubility parameter, δΗ of <15.0 (J/cm ³ ) ¹ ' ² . Preferably the Hansen solubility parameter, δΗ is 2.0 to 14.5 (J/cm ³ ) ¹ ' ² , more preferably 3.0 to 12.0 (J/cm ³ ) ¹ ' ² and still more preferably 3.5 to 10.0 (J/cm ³ ) ¹ ' ² .

The polar solvent present in the antifouling coating composition preferably has a Hansen solubility parameter, δΡ of <10.0 (J/cm ³ ) ¹ ' ² . Preferably the Hansen solubility parameter, δΡ is 1 .5 to 8.5 (J/cm ³ ) ¹ ' ² , more preferably 2.0 to 8.0 (J/cm ³ ) ¹ ' ² and still more preferably 2.5 to 7.5 (J/cm ³ ) ¹ ' ² .

The polar solvent present in the antifouling coating composition preferably has a Hansen solubility parameter, δϋ of <20.0 (J/cm ³ ) ¹ ' ² . Preferably the Hansen solubility parameter, δϋ is 10.0 to 20.0 (J/cm ³ ) ¹ ' ² , more preferably 12.0 to 18.0 (J/cm ³ ) ¹ ' ² and still more preferably 14.0 to 16.5 (J/cm ³ ) ¹ ' ² .

The Hansen solubility parameters, δΗ, δΡ and δϋ are available for a wide range of solvents, e.g. in HSPiP (Hansen Solubility Parameters in Practice) software 4th Edition 4.1 .07. The Hansen solubility parameters for some polar solvents suitable for use in the antifouling coating composition of the invention are provided below.

The polar solvent present in the antifouling coating composition preferably has a boiling point of 75°C to 250°C and more preferably a boiling point of 1 10°C to 180°C.

The polar solvent present in the antifouling coating composition of the invention preferably comprises at least one heteroatom selected from O, N, P and S and preferably O. More preferably the polar solvent present in the composition comprises one or two heteroatoms and still more preferably one or two O atoms.

The polar solvent present in the antifouling coating composition of the invention preferably comprises one or more functional groups selected from -O- (ether), -OC(O)- (ester), -C(O)- (ketone) and -C(OH)- (secondary alcohol). Particularly preferably the polar solvent comprises one or more -OC(O)-, -(CO)- and -C(OH)- functional groups. Preferably the polar solvent present in the composition does not comprise a primary alcohol functional group.

The polar solvent present in the antifouling coating composition of the present invention is preferably selected from formulae (la)-(lc) and more preferably from formulae (lb) or (Ic):

wherein

each R is independently selected from linear or branched Ci _-8 alkyl groups;

R ¹ is selected from linear or branched Ci _-8 alkyl groups, optionally interrupted by

O- group; and R ² is selected from H or linear or branched Ci _-8 alkyl groups, optionally interrupted by one -O- group.

In preferred solvents of formulae (la)-(lc) R is linear or branched Ci _-6 alkyl, more preferably Ci _-4 alkyl and still more preferably methyl. Preferably R is linear.

In preferred solvents of formulae (la)-(lc) R ¹ is linear or branched C _2-8 alkyl and more preferably C _4-5 alkyl. Representative examples of preferred R ¹ groups include n- butyl, n-pentyl, i-butyl and i-pentyl.

In other preferred solvents of formulae (la)-(lc) R ¹ is linear or branched Ci _-8 alkyl groups, interrupted by one -O- group. In this case R ¹ is preferably linear or branched C _2-4 alkyl. Representative examples of preferred R ¹ groups include - CH ₂ OCH ₃ and -CH(CH ₃ )CH ₂ OCH ₃ .

In preferred solvents of formula (la) R ² is H.

Representative examples of solvents of formula (la), along with their evaporation rate relative to n-BuAc and their Hansen solubility parameters are provided in the table below. These are preferred solvents of formula (la) for the antifouling coating composition of the present invention. 1 -methoxy-2-propanol is a preferred solvent of formula (la).

Representative examples of solvents of formula (lb), along with their evaporation rate relative to n-BuAc and their Hansen solubility parameters are provided in the table below. These are preferred solvents of formula (lb) for the antifouling coating composition of the present invention. n-Butyl acetate, isoamyl acetate and 1 - methoxy-2-propyl acetate are preferred solvents of formula (lb). Name Evaporation δΗ δΡ δϋ

rate, (J/cm ³ ) ¹ ' ² (J/cm ³ ) ¹ ' ² (J/cm ³ ) ¹ ' ² n-BuAc = 1

n-Propyl acetate 2.1 7.6 4.3 15.3

Isopropyl acetate 3.5 8.2 4.5 14.9 n-Butyl acetate 1 .0 6.3 3.7 15.8

Isobutyl acetate 1 .5 6.3 3.7 15.1 t-Butyl acetate 2.8 6.0 3.7 15.0

Amyl acetate 0.4 6.1 3.3 15.8

Isoamyl acetate 0.5 7.0 3.1 15.3 n-Propyl propionate 1 .2 5.7 5.8 15.7

Butyl propionate 0.5 5.9 5.5 15.7

Isobutyl isobutyrate 0.4 5.8 2.8 15.1 n-Pentyl propionate 0.2 5.7 5.2 15.8

1 -Methoxy-2-propyl acetate 0.4 9.8 5.6 15.6

Ethyl 3-ethoxypropionate 0.12 8.8 3.3 16.2

Representative examples of solvents of formula (lc), along with their evaporation rate relative to n-BuAc and their Hansen solubility parameters are provided in the table below. These are preferred solvents of formula (lc) for the antifouling coating composition of the present invention. Methyl isoamyl ketone, methyl amyl ketone and methyl isobutyl ketone are preferred solvents of formula (lc).

Particularly preferably the antifouling coating composition of the present invention comprises a polar solvent selected from 1 -methoxy-2-propanol, n-butyl acetate, isoamyl acetate, 1 -methoxy-2-propyl acetate, methyl isoamyl ketone, methyl amyl ketone, and methyl isobutyl ketone. These solvents have been found to produce antifouling coating compositions that are stable to long term storage, i.e. they do not gel or thicken during long term storage.

The antifouling coating composition of the present invention preferably comprises at least 3 wt% polar solvent, based on the total amount of solvent present in the composition. Preferably the composition comprises at least 4 wt% polar solvent, more preferably 5 to 60 wt% and still more preferably 7 to 55 wt% polar solvent, based on the total amount of solvent present in the composition. These levels of polar solvent ensure the composition is stable to storage for extended periods of time.

The amount of polar solvent present in the overall antifouling coating composition is preferably 0.5 to 30 wt%, more preferably 1 to 25 wt% and still more preferably 2 to 20 wt% based on the total weight of the composition.

Non-polar solvent

The antifouling coating composition comprises a non-polar solvent. Preferably the non-polar solvent is organic.

Examples of suitable non-polar organic solvents are aromatic hydrocarbons such as xylenes, toluene, mesitylene and aliphatic hydrocarbons such as white spirit and limonene. Combinations of different non-polar solvents may also be used. Preferably, however, the non-polar solvent is an aromatic hydrocarbon and particularly preferably the non-polar solvent is xylene. Suitable non-polar organic solvents are commercially available.

The amount of solvent, and particularly non-polar solvent, present in the antifouling coating compositions of the present invention is preferably as low as possible as this minimizes the VOC content. Preferably the composition comprises up to to 98 wt% non-polar solvent or up to 97.5 wt% non-polar solvent, more preferably 40 to 90 wt% and still more preferably 45 to 85 wt% non-polar solvent, based on the total amount of solvent present in the composition. Preferably non-polar solvent is present in the compositions of the invention in an amount of 0-35 wt%, more preferably 1 -30 wt% and still more preferably 1 -25 wt% based on the total weight of the composition.

Further preferred antifouling coating compositions of the present invention comprise 2.5-60 wt% polar solvent and 40 to 97.5 wt% non-polar solvent, more preferably 5-60 wt% polar solvent and 40 to 95 wt% non-polar solvent and still more preferably 7-55 wt% polar solvent and 45-93 wt% non-polar solvent, based on the total amount of solvent present in the composition. The skilled man will appreciate that the solvent content will vary depending on the other components present.

Silyl (meth)acrylate polymer

The silyl (meth)acrylate polymer present in the antifouling coating composition of the present invention is preferably a copolymer.

Preferably the silyl (meth)acrylate polymer present in the antifouling coating composition of the present invention comprises a residue of at least one silyl (meth)acrylate monomer and preferably a residue of at least one silyl (meth)acrylate monomer of formula (II):

R ⁴ is H or CH ₃ ;

R ⁵ are each independently selected from linear or branched Ci _-4 alkyl groups;

R ⁶ are each independently selected from the group consisting of linear or branched Ci. 20 alkyl groups, C3-12 cycloalkyl groups, optionally substituted C _6- 2o aryl groups and -OSi(R ⁷ ) ₃ groups;

each R ⁷ is independently a linear or branched Ci _-4 alkyl group;

Z is a Ci-C ₄ alkylene;

m is an integer from 0 to 1 ; and

n is an interger from 0 to 5.

Examples of substituted aryl groups include aryl groups substituted with at least one substituent selected from halogens, alkyl groups having 1 to about 8 carbon atoms, acyl groups, or a nitro group. Particularly preferred aryl groups include substituted and unsubstituted phenyl, benzyl, phenalkyl or naphthyl.

Representative examples of R ⁵ and R ⁷ groups include methyl, ethyl, n-propyl, i- propyl, n-butyl, i-butyl and t-butyl.

Representative examples of Z include -CH ₂ -, -CH ₂ CH ₂ -, -(CH ₂ )3- and -(CH ₂ ) ₄ . Branched C _3-4 alkylene groups are also envisaged, e.g. -CH ₂ CH(CH3)CI-l2-.

In preferred monomers of formula (II), m is 0. In preferred monomers of formula (II), n is 0.

In preferred monomers of formula (II), R ⁶ are each independently selected from linear or branched Ci _-2 o alkyl groups. Still more R ⁶ are each independently selected from linear or branched Ci _-8 alkyl groups and still more preferably from C _2- 6 alkyl groups.

Examples of silyl (meth) acrylate monomers, e.g. as defined by the general formula (II) include:

(meth)acrylates such as triisopropylsilyl (meth)acrylate, tri-n-butylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, tri-sec-butylsilyl (meth)acrylate, butyldiisopropylsilyl (meth)acrylate, tert-butyldimethylsilyl (meth)acrylate, thexyldimethylsilyl (meth)acrylate, tert-butyldiphenylsilyl (meth)acrylate, triisopropylsiloxycarbonylmethyl (meth)acrylate, triisopropylsiloxycarbonylethyl (meth)acrylate, tert-butyldiphenylsiloxycarbonylmethyl (meth)acrylate, nonamethyltetrasiloxy (meth)acrylate, bis(trimethylsiloxy)methylsilyl (meth)acrylate and tris(trimethylsiloxy)silyl (meth)acrylate.

Preferred monomers are alkylsilyl (meth)acrylates and more preferably trialkylsilyl (meth)acrylates, wherein one or more of the alkyl group(s) is branched. Particularly preferred monomers include triisopropylsilyl (meth)acrylate, tri-n-butylsilyl (meth)acrylate, thexyldimethylsilyl (meth)acrylate and tert-butyldiphenylsilyl (meth)acrylate. Triisopropylsilyl acrylate and triisopropylsilyl methacrylate are particularly preferred.

The silyl (meth)acrylate polymer present in the antifouling coating composition of the present invention preferably comprises 1 -3 different monomers of formula (II) and more preferably 1 or 2 different monomers of formula (II).

Preferably the silyl (meth)acrylate polymer present in the antifouling coating composition of the present invention further comprises a residue of one or more (meth)acrylate monomers. Preferred meth(acrylate) monomers present in the silyl (meth)acrylate polymer are those of formulae (llla)-(lllc):

wherein R is hydrogen or methyl, R is a cyclic ether and X is a Ci-C ₄ alkylene; or

wherein R ⁸ is hydrogen or methyl, and R ¹⁰ is a C ₃ -Ci ₈ substituent with at least one oxygen or nitrogen atom, preferably at least one oxygen atom; or

wherein R ⁸ is hydrogen or methyl, and R ¹¹ is a CrC ₈ hydrocarbyl

In preferred monomers of formula (Ilia) R ⁸ is hydrogen or methyl, R ⁹ is a cyclic ether (such as oxolane, oxane, dioxolane, dioxane optionally alkyl substituted) and X is a C-i-4 alkylene, preferably a Ci _-2 alkylene. The cyclic ether may contain a single oxygen atom in the ring or 2 or 3 oxygen atoms in the ring. The cyclic ether may contain a ring comprising 2 to 8 carbon atoms, such as 3 to 5 carbon atoms. The whole ring might comprise 4 to 8 atoms, such as 5 or 6 atoms.

The cyclic ether ring may be substituted such as by one or more, such as one, C-i-6 alkyl group. That substituent group might be at any position on the ring including the position that binds to the X group.

Suitable monomers of formula (Ilia) include tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, isopropylideneglycerol methacrylate, glycerolformal methacrylate and cyclic trimethylolpropane formal acrylate.

Formula (Ilia) most preferably represents tetrahydrofurfuryl acrylate having the structure below:

In preferred monomers of formula (1Mb) R ⁸ is hydrogen or methyl, and R ¹⁰ is a C3-18 substituent containing at least one oxygen or nitrogen atom, preferably at least one oxygen atom.

In preferred monomers of formula (1Mb) R ¹⁰ is of formula -(CH ₂ CH ₂ 0) _M -R ¹² where R ¹² is a CMO hydrocarbyl substituent, preferably a CMO alkyl or a C _6- io aryl substituent, and m is an integer in the range of 1 to 6, preferably 1 to 3. Preferably R ¹⁰ is of formula -(CH ₂ CH ₂ 0) _M -R ¹² where R ¹² is an alkyl substituent, preferably methyl or ethyl, and m is an integer in the range of 1 to 3, preferably 1 or 2.

Preferred monomers of formula (1Mb) include one or more of 2-methoxyethyl methacrylate, 2-methoxyethyl acrylate, 2-ethoxyethyl methacrylate, 2-(2- ethoxyethoxy)ethyl methacrylate and 2-(2-ethoxyethoxy)ethyl acrylate.

In preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention it is generally not preferred to have monomers of both formula (Ilia) and (1Mb) present.

In preferred monomers of formula (lllc), R ⁸ is hydrogen or methyl, and R ¹¹ is a

C ₁ -8 hydrocarbyl substituent, preferably a Ci _-8 alkyl substituent, most preferably methyl, ethyl, n-butyl or 2-ethylhexyl.

Preferred monomers of formula (lllc) include methyl methacrylate and n-butyl acrylate.

Preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the invention comprise at least one monomer of formula (lllc).

The silyl (meth)acrylate polymer present in the antifouling coating composition of the present invention may optionally comprise other polymerizable monomers. Examples include alkyl esters of acrylic acid and methacrylic acid such as 3,5,5- trimethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, isotridecyl (meth)acrylate, octadecyl (meth)acrylate; cyclic alkyl esters of acrylic acid and methacrylic acid such as cyclohexyl (meth)acrylate, 4-tert- butylcyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, isobornyl (meth)acrylate; aryl esters of acrylic acid and methacrylic acid such as phenyl (meth)acrylate, benzyl (meth)acrylate, naphthyl (meth)acrylate; hydroxyalkyl ester of acrylic acid and methacrylic acid such as 2- hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, poly(ethylene glycol) (meth)acrylate, poly(propylene glycol) (meth)acrylate; alkoxyalkyi and poly(alkoxy)alkyl ester of acrylic acid and methacrylic acid such as poly(ethylene glycol) methyl ether (meth)acrylate, poly(propylene glycol) methyl ether (meth)acrylate, glycidyl (meth)acrylate; other functional monomers of acrylic acid and methacrylic acid such as methacrylic anhydride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl dodecanoate, vinyl benzoate, vinyl 4-tert-butylbenzoate, VeoVaTM 9, VeoVaTM 10; N-vinyl lactams, N- vinyl amides such as N-vinyl pyrrolidone; vinyl monomers such as styrene, a-methyl styrene and vinyl toluene.

Preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention have a weight average molecular weight of 5000 to 80000, more preferably 10000 to 70000 and still more preferably 20000 to 60000. Preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention have a number average molecular weight of 3000 to 20000, more preferably 5000 to 15000 and still more preferably 7000 to 12000. Preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention have a polydispersity index (PDI), calculated by the equation PDI = Mw/Mn of 1 .2 to 5 and more preferably 2.5 to 4.0. Preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention have a Tg of 10 °C to 80 °C, more preferably 15 °C to 70 °C and still more preferably 20 °C to 60 °C.

The antifouling coating composition may comprise one or more (e.g. 1 , 2, 3, 4 or 5) silyl (meth)acrylate polymers as hereinbefore described. Preferred antifouling coating compositions of the present invention comprise 1 , 2, 3 or 4 silyl (meth) acrylate polymers and still more preferably 1 or 2 silyl (meth)acrylate polymers.

In preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention, the amount of monomers of formula (II) is preferably 5 to 80 wt%, more preferably 20 to 70 wt% and still more preferably 40 to 65 wt% based on the total weight of monomers. In preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention, the total amount of monomers of formula (Ilia) and (1Mb) is preferably 1 to 40 wt%, more preferably 2 to 30 wt% and still more preferably 5 to 25 wt% based on the total weight of monomers. In preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention, the amount of monomers of formula (III c) is preferably 1 to 50 wt%, more preferably 2 to 45 wt% and still more preferably 5 to 40 wt% based on the total weight of monomers. In preferred silyl (meth)acrylate polymers present in the antifouling coating composition of the present invention, the amount of other monomers is preferably 0 to 20 wt%, more preferably 0 to 15 wt% and still more preferably 0 to 10 wt% based on the total weight of monomers. Preferably the total amount of silyl (meth)acrylate polymer present in the compositions of the invention is 1 -50 wt%, more preferably 2-40 wt% and still more preferably 5-35 wt%, based on the total weight of the composition.

Suitable silyl (meth)acrylate polymers may be prepared using polymerization techniques known in the art. The silyl (meth)acrylate polymer may, for example, be obtained by polymerizing a monomer mixture in the presence of a polymerization initiator by any of various methods such as solution polymerization, bulk polymerization, emulsion polymerization, and suspension polymerization. Controlled polymerization techniques may, for example, be employed. When preparing a coating composition using the silyl (meth)acrylate polymer as hereinbefore described, the polymer is preferably diluted with solvent to give a polymer solution having an appropriate viscosity. From this standpoint, it is desirable to employ solution polymerization or bulk polymerization to prepare the silyl (meth)acrylate polymer. Examples of suitable polymerization initiators include azo compounds such as dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-methylbutyronitrile), 2,2'- azobis(isobutyronitrile) and 1 ,1 '-azobis(cyanocyclohexane) and peroxides such as tert- butyl peroxypivalate, tert- butyl peroxy-2-ethylhexanoate, tert-butyl peroxydiethylacetate, tert-butyl peroxyisobutyrate, di-tert-butyl peroxide, tert-butyl peroxybenozate, and tert-butyl peroxyisopropylcarbonate, tert-amyl peroxypivalate, tert-amyl peroxy-2- ethylhexanoate, 1 ,1 -di(tert-amyl peroxy)cyclohexane and dibenzoyi peroxide. These compounds may be used alone or as a mixture of two or more thereof.

Examples of suitable solvents for polymerisation include aromatic hydrocarbons such as xylene, toluene, mesitylene; ketones such as methyl isobutyl ketone, methyl isoamyl ketone, cyclopentanone, cyclohexanone; esters such as butyl acetate, amyl acetate, isoamyl acetate, propylene glycol methyl ether acetate; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dibutyl ether; alcohols such as 2-butanol, benzyl alcohol; ether alcohols such as 1 -methoxy-2-propanol; aliphatic hydrocarbons such as white spirit; and optionally a mixture of two or more solvents. These compounds are used alone or as a mixture of two or more thereof.

Alternatively suitable silyl (meth)acrylate polymers may be purchased commercially.

Tralopyril

The antifouling coating composition of the present invention comprises tralopyril or a salt thereof. This is an organic antifouling agent that is capable of preventing or removing marine fouling from a surface. The organic biocide, tralopyril is sold by Janssen as Econea®. Tralopyril is 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1 H- pyrrole-3-carbonitrile and has the structure shown below:

Tralopyril exhibits a broad spectrum of activity against various marine organisms including barnacles, mussels and tube worms. Salts thereof may also be used. The term tralopyril is used below to discuss this biocide. The teaching equally applies to salts thereof.

Antifouling coating compositions of the present invention comprise tralopyril in an amount to ensure biocidal activity. Preferred amounts are 0.5 to 10 wt% (dry solids), preferably 1 to 7 wt%, preferably 2 to 6 wt%.

One advantage of the use of tralopyril is that it exhibits greater biocidal efficacy towards marine organisms compared to metal biocides, meaning that the amount of metal biocide can be reduced or eliminated. In turn, unwanted effects such as discoloration due to the precipitation of copper salts is avoided or reduced. A disadvantage of using tralopyril is that it causes instability in silyl (meth)acrylate containing compositions. This problem is, however, overcome in the antifouling coating compositions herein which comprises a polar solvent.

Optionally the antifouling coating composition comprises one or more additional antifouling agents. The terms antifouling agent, biologically active compounds, antifoulant, biocide, toxicant are used in the industry to describe known compounds that act to prevent marine fouling on a surface. The further antifouling agent present in the compositions of the invention is preferably a marine antifouling agent. The antifouling agent may be inorganic, organometallic or organic. Suitable antifouling agents are commercially available.

Examples of inorganic antifouling agents include copper and copper compounds such as copper oxides, e.g. copper(l) oxide and copper(ll) oxide; copper alloys, e.g. copper-nickel alloys; copper salts, e.g. copper(l) thiocyanate and copper sulphide. Examples of organometallic antifouling agents include zinc pyrithione; organocopper compounds such as copper pyrithione, copper acetate, copper naphthenate, oxine copper, copper nonylphenolsulfonate, copper bis(ethylenediamine)bis(dodecylbenzensulfonate) and copper bis(pentachlorophenolate); dithiocarbamate compounds such as zinc bis(dimethyldithiocarbamate) [ziram], zinc ethylenebis(dithiocarbamate) [zineb], manganese ethylenebis(dithiocarbamate) [maneb] and manganese ethylene bis(dithiocarbamate) complexed with zinc salt [mancozeb].

Examples of organic antifouling agents include heterocyclic compounds such as 2-(tert-butylamino)-4-(cyclopropylamino)-6-(methylthio)-1 ,3,5- triazine [cybutryne], 4,5- dichloro-2-n-octyl-4-isothiazolin-3-one [DCOIT], 1 ,2-benzisothiazolin-3-one, 2- (thiocyanatomethylthio)-1 ,3-benzothiazole [benthiazole] and 2,3,5,6-tetrachloro-4- (methylsulphonyl) pyridine; urea derivatives such as 3-(3,4-dichlorophenyl)-1 ,1 - dimethylurea [diuron]; amides and imides of carboxylic acids, sulphonic acids and sulphenic acids such as N-(dichlorofluoromethylthio)phthalimide, N- dichlorofluoromethylthio-N',N'-dimethyl-N-phenylsulfamide [dichlofluanid], N- dichlorofluoromethylthio-N',N'-dimethyl-N-p-tolylsulfamide [tolylfluanid] and N-(2,4,6- trichlorophenyl)maleimide; other organic compounds such as pyridine triphenylborane [TPBP], amine triphenylborane, 3-iodo-2-propynyl N-butylcarbamate [iodocarb], 2,4,5,6-tetrachloroisophthalonitrile and p-((diiodomethyl)sulphonyl) toluene.

Other examples of antifouling agents include tetraalkylphosphonium halogenides, guanidine derivatives, imidazole containing compounds such as 4-[1 -(2,3- dimethylphenyl)ethyl]-1 H-imidazole [medetomidine] and derivatives, macrocyclic lactones includes avermectins and derivatives thereof such as ivermectine and spinosyns and derivatives thereof such as spinosad, and enzymes such as oxidase, proteolytically, hemicellulolytically, cellulolytically, lipolytically and amylolytically active enzymes.

Preferred further antifouling agents are copper(l) oxide, copper thiocyanate, zinc pyrithione, copper pyrithione, zinc ethylenebis(dithiocarbamate) [zineb], 2-(tert- butylamino)-4-(cyclopropylamino)-6-(methylthio)-1 ,3,5-triazine [cybutryne], 4,5-dichloro- 2-n-octyl-4-isothiazolin-3-one [DCOIT], N-dichlorofluoromethylthio-N',N'-dimethyl-N- phenylsulfamide [dichlofluanid], N-dichlorofluoro methylthio-N',N'-dimethyl-N-p- tolylsulfamide [tolylfluanid] and 4-[1 -(2, 3-dimethylphenyl)ethyl]-1 H-imidazole [medetomidine]. Especially preferred further antifouling agents are copper(l) oxide, copper(l) thiocyanate, zinc pyrithione, copper pyrithione, zinc ethylenebis(dithiocarbamate) [zineb], 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one [DCOIT], and 4-[1 -(2,3- dimethylphenyl)ethyl]-1 H-imidazole [medetomidine].

The antifouling agents may be used alone or in mixtures as different antifouling agents operate against different marine fouling organisms. Mixtures of antifouling agents are generally preferred. One preferred mixture of antifouling agents is active against marine invertebrates, such as barnacles, tubeworms, bryozoans and hydroids; and plants, such as algae (seaweed and diatoms); and bacteria

Some preferred coating compositions of the present invention are free of an inorganic copper antifouling agent. Such compositions preferably comprise a combination of tralopyril and one or more agents selected from zinc pyrithione, zineb and 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one.

Other preferred coating compositions comprise tralopyril, copper(l) oxide and/or copper(l) thiocyanate and one or more selected from copper pyrithione, zineb and 4,5- dichloro-2-n-octyl-4-isothiazolin-3-one.

The combined amount of antifouling agents present in the antifouling composition may form up to 60 wt% of the coating composition, such as 0.1 to 50 wt%, e.g. 0.2 to 45 wt%, based on the total weight of the composition. Where inorganic copper compounds are present, a suitable amount of antifouling agent might be 5 to 60 wt% in the coating composition. Where inorganic copper compounds are avoided, lower amounts might be used such as 0.1 to 25 wt%, e.g. 0.2 to 20 wt%. It will be appreciated that the amount of antifouling agent will vary depending on the end use and the antifouling agent used. The use of these antifouling agents is known in antifouling coatings and their use would be familiar to the skilled man. The antifouling agent may be encapsulated or adsorbed on an inert carrier or bonded to other materials for controlled release. These percentages refer to the amount of active antifouling agent present and not therefore to any carrier used.

Preferred antifouling coating compositions of the invention comprise:

(i) 1 -50 wt%, more preferably 2-40 wt% of a silyl (meth)acrylate polymer;

(ii) 0.5-10 wt%, more preferably 1 -7 wt% of tralopyril;

(iii) 0.5-30 wt%, more preferably 1 -25 wt% of a polar solvent; and

(iv) 0-35 wt%, more preferably 1 -30 wt% of a non-polar solvent;

wherein wt% is based on the total weight of the composition. Carboxylic acid compounds and derivatives thereof

The antifouling coating composition of the present invention preferably comprises one or more compounds comprising a carboxylic acid group and/or derivatives thereof. Derivatives include metal salts of compounds comprising a carboxylic acid group (also referred to as metal carboxylates) and esters of compounds comprising a carboxylic acid group, preferably methyl esters.

Preferred carboxylic acids compounds are rosins. The antifouling coating composition of the present invention preferably comprises rosin and/or a rosin derivative. Representative examples of rosins include wood rosin, tall oil rosin and gum rosin. Representative examples of rosin derivatives include hydrogenated and partially hydrogenated rosin, disproportionated rosin, dimerised rosin, polymerised rosin, maleic acid esters, fumaric acid esters and other esters of rosin and hydrogenated rosin, copper rosinate, zinc rosinate, calcium rosinate, magnesium rosinate and other metal rosinates of rosin and polymerised rosin and others as described in WO 97/44401 . Preferably the rosin or rosin derivative present in the antifouling coating composition of the present invention is a gum rosin.

Preferably the rosin present comprises rosin acids selected from abietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, secodehydroabietic acid, pimaric acid, isopimaric acid, levopimaric acid, palustric acid, sandaracopimaric acid, communic acid and derivatives thereof.

Examples of other carboxylic acid compounds include organic acid compounds such as Versatic™ acids, isononanoic acid, 2-ethylhexanoic acid, naphthenic acid, and other organic acids as described in EP1342756; cyclic carboxylic acid compounds such as 1 -methyl-3-(4-methyl-3-pentenyl)-3-cyclohexen-1 -yl-carboxylic acid, 1 -methyl-4-(4- methyl-3-pentenyl)-4-cyclohexen-1 -yl-carboxylic acid, 1 ,4,5-trimethyl-2-(2-methyl-1 - propenyl)-3-cyclohexen-1 -yl-carboxylic acid and 1 ,5,6-trimethyl-3-(2-methyl-1 - propenyl)-4-cyclohexen-1 -yl-carboxylic acid and others as described in EP 1695956 and JP2016216651A.

Preferably compounds comprising a carboxylic acid group and/or derivatives thereof (e.g. rosin and/or a derivative thereof) is present in the compositions of the invention in an amount of 0-40 wt%, more preferably 1 -35 wt% and still more preferably 2-25 wt%, based on the total weight of the composition. A mixture of one or more compounds comprising a carboxylic acid group and/or derivatives thereof may also be used. Compounds comprising a carboxylic acid group and/or derivatives thereof including rosin and rosin derivatives are commercially available. For example, gum rosin which is preferably present in the coating compositions of the invention, is commercially available.

Binder components

In addition to the silyl (meth)acrylate polymer, an additional binder may optionally be used to adjust the properties of the antifouling coating composition. Examples of binders that can be used include:

(meth)acrylic polymers and copolymers, in particular acrylate binders, such as poly(n-butyl acrylate), poly(n-butyl acrylate-co-isobutyl vinyl ether) and others as described in WO03/070832 and EP2128208;

hydrophilic copolymers for example (meth)acrylate copolymers as described in GB2152947 and poly(N-vinyl pyrrolidone) copolymers and other copolymers as described in EP0526441 ;

vinyl ether polymers and copolymers, such as poly(methyl vinyl ether), poly(ethyl vinyl ether), poly(isobutyl vinyl ether), polyvinyl chloride-co-isobutyl vinyl ether);

aliphatic polyesters, such as poly(lactic acid), poly(glycolic acid), poly(2- hydroxybutyric acid), poly(3-hydroxybutyric acid), poly(4-hydroxyvaleric acid), polycaprolactone and aliphatic polyester copolymer containing two or more of the units selected from the above mentioned units;

polyoxalates as described in WO2009/100908 and other condensation polymers as described in W096/14362;

alkyd resins and modified alkyd resins; and

hydrocarbon resin, e.g. as described in WO201 1/092143, such as hydrocarbon resin formed only from the polymerisation of at least one monomer selected from a C5 aliphatic monomer, a C9 aromatic monomer, an indene coumarone monomer, or a terpene or mixtures thereof.

Especially suitable additional binders are (meth)acrylic polymers and copolymers.

Extenders and pigments

The term extender is used herein to encompass extenders as well as fillers. These compounds increase the bulk of the composition. Examples of extenders and fillers are minerals such as dolomite, plastorite, calcite, quartz, barite, magnesite, aragonite, silica, wollastonite, talc, chlorite, mica, kaolin and feldspar; synthetic inorganic compounds such as zinc phosphates, calcium carbonate, magnesium carbonate, barium sulphate, calcium silicate and silica; polymeric and inorganic microspheres such as uncoated or coated hollow and solid glass beads, uncoated or coated hollow and solid ceramic beads, hollow, porous and compact beads of polymeric materials such as poly(methyl methacrylate), poly(methyl methacrylate-co- ethylene glycol dimethacrylate), poly(styrene-co-ethylene glycol dimethacrylate), poly(styrene-co-divinylbenzene), polystyrene and polyvinyl chloride).

The pigments may be inorganic pigments, organic pigments or a mixture thereof. Inorganic pigments are preferred. Examples of inorganic pigments include titanium dioxide, iron oxides and zinc oxide. Examples of organic pigments are naphthol red, phthalocyanine compounds, azo pigments and carbon black.

Preferably the total amount of extender, filler and/or pigment present in the compositions of the invention is 0-70 wt%, more preferably 1 -60 wt% and still more preferably 2-50 wt%, based on the total weight of the composition. The skilled man will appreciate that the extender and pigment content will vary depending on the other components present and the end use of the coating composition. Dehydrating agent

The antifouling coating composition of the present invention optionally comprises a dehydrating agent, also refered to as water scavenger or drying agent. Preferably the dehydrating agent is a compound which removes water from the composition in which it is present. Dehydrating agents improve the storage stability of the antifouling coating composition by removing moisture introduced from raw materials, such as pigments and solvents, or water formed by reaction between carboxylic acid compounds and bivalent and trivalent metal compounds in the antifouling coating composition. The dehydrating agents and desiccants that may be used in the antifouling coating compositions include organic and inorganic compounds.

The dehydrating agents can be hygroscopic materials that absorb water or binds water as crystal water, often refered to as desiccants. Examples of desiccants include calcium sulphate hemihydrate, anhydrous calcium sulphate, anhydrous magnesium sulphate, anhydrous sodium sulphate, anhydrous zinc sulphate, molecular sieves and zeolites. The dehydrating agent can be a compound that chemically reacts with water. Examples of dehydrating agents that reacts with water include orthoesters such as trimethyl orthoformate, triethyl orthoformate, tripropyl orthoformate, triisopropyl orthoformate, tributyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate, tributyl orthoacetate and triethyl orthopropionate; ketals; acetals; enolethers; orthoborates such as trimethyl borate, triethyl borate, tripropyl borate, triisopropyl borate, tributyl borate and tri-tert-butyl borate; organosilanes such as trimethoxymethyl silane, vinyltrimethoxysilane, phenyltrimethoxysilane, tetraethoxysilane and ethyl polysilicate.

Preferred dehydrating agents are those that chemically react with water. Particularly preferred dehydrating agents are organosilanes. Organosilanes are particularly preferred in antifouling coating compositions comprising inorganic copper antifouling agent. Still more preferably organosilanes present in antifouling coating compositions comprising copper (I) oxide.

Preferably the dehydrating agent is present in the compositions of the invention in an amount of 0-5 wt%, more preferably 0.5-2.5 wt% and still more preferably 1 .0-2.0 wt%, based on the total weight of the composition.

Preferably the antifouling coating compositions of the present invention do not comprise a carbodiimide compound. In particular the antifouling coating composition of the present invention preferably does not comprise a compound containing a functional group represented by the formula [-N=C=N-].

Other Components

The antifouling coating composition of the present invention preferably comprises one or more other components. Examples of other components that can be added to the antifouling coating composition are reinforcing agents, thixotropic agents, thickening agents, anti-settling agents, dispersing agents, wetting agents and plasticizers.

Examples of reinforcing agents are flakes and fibres. Fibres include natural and synthetic inorganic fibres such as silicon-containing fibres, carbon fibres, oxide fibres, carbide fibres, nitride fibres, sulphide fibres, phosphate fibres, mineral fibres; metallic fibres; natural and synthetic organic fibres such as cellulose fibres, rubber fibres, acrylic fibres, polyamide fibres, polyimide fibres, polyester fibres, polyhydrazide fibres, polyvinylchloride fibres, polyethylene fibres and others as described in WO 00/77102. Preferably, the fibres have an average length of 25 to 2,000 μηη and an average thickness of 1 to 50 μηη with a ratio between the average length and the average thickness of at least 5. Preferably reinforcing agents are present in the compositions of the invention in an amount of 0-20 wt%, more preferably 0.5-15 wt% and still more preferably 1 -10 wt%, based on the total weight of the composition.

Examples of thixotropic agents, thickening agents and anti-settling agents are silicas such as fumed silicas, organo-modified clays, amide waxes, polyamide waxes, amide derivatives, polyethylene waxes, oxidised polyethylene waxes, hydrogenated castor oil wax, ethyl cellulose, aluminium stearates and mixtures thereof. Preferably thixotropic agents, thickening agents and anti-settling agents are each present in the composition of the invention in an amount of 0-10 wt%, more preferably 0.5-6 wt% and still more preferably 1.0-3.0 wt%, based on the total weight of the composition.

Examples of plasticizers are chlorinated paraffins, phthalates, phosphate esters, sulphonamides, adipates and epoxidised vegetable oils. Preferably plasticizers are present in the compostions of the invention in an amount of 0-20 wt%, more preferably 1 -15 wt% and still more preferably 1 -10 wt%, based on the total weight of the composition.

Composition and Paint

The present invention also relates to a method of preparing the composition as hereinbefore described wherein the components present in the composition are mixed. In a preferred method of the invention tralopyril is premixed with polar solvent and mixed with silyl (meth)acrylate polymer and non-polar solvent and other optional ingredients. Any conventional production method may be used. In a preferred method of the invention, silyl (meth)acrylate polymer and non-polar solvent and other optional ingredients are dispersed and milled and cooled prior to addition of tralopyril or a mixture comprising tralopyril and polar solvent.

The composition as described herein may be prepared in a suitable concentration for use, e.g. in spray painting. In this case, the composition is itself a paint. Alternatively the composition may be a concentrate for preparation of paint. In this case, further solvent is added to the composition described herein to form paint. Preferred solvents are as hereinbefore described in relation to the composition.

After mixing, and optionally after addition of solvent, the antifouling coating composition or paint is preferably filled into a container. Suitable containers include cans, drums and tanks. The antifouling coating composition is preferably supplied as a one-pack. Thus the composition is preferably supplied in a ready-mixed or ready to use form. Optionally the one-pack product may be thinned with solvents prior to application.

The antifouling coating composition and paint of the invention preferably has a solids content of 40-80 vol%, more preferably 45-70 vol% and still more preferably 50- 65 vol%.

Preferably the antifouling coating composition and paint of the invention has a viscosity of 50 to 2000 cP, more preferably 50-1000 cP, still more preferably 100-900 cP and still more preferably 150-800 cP. Preferably viscosity is measured using a Cone and Plate viscometer (ISO 2884-1 :1999) as described in the examples.

Preferably the antifouling coating composition and paint of the invention has a viscosity of 50 to 2000 cP, more preferably 50-1000 cP, still more preferably 100-900 cP and still more preferably 150-800 cP after storage for 1 week at 52°C according to ASTM D1849-95(2014). Preferably the antifouling coating composition and paint of the invention has a viscosity of 50 to 2000 cP, more preferably 50-1000 cP, still more preferably 100-900 cP and still more preferably 150-800 cP after storage for 2 weeks at 52°C according to ASTM D1849-95(2014). Preferably the antifouling coating composition and paint of the invention has a viscosity of 50 to 2000 cP, more preferably 50-1000 cP, still more preferably 100-900 cP and still more preferably 150- 800 cP after storage for 4 weeks at 52°C according to ASTM D1849-95(2014). Preferably the antifouling coating composition of the invention does not form a gel during storage for 4 weeks at 52°C according to ASTM D1849-95(2014). Preferably viscosity is measured using a Cone and Plate viscometer (ISO 2884-1 :1999) as described in the examples.

Preferably the antifouling coating composition and paint of the invention has a content of volatile organic compounds (VOC) of 50 to 500 g/L, preferably 50 to 420 g/L, e.g. 50 to 390 g/L. VOC content can be calculated (ASTM D5201 -01 ) or measured (EPA, method 24).

Preferably the antifouling coating composition and paint of the invention has a viscosity of 50-1000 cP and a content of VOCs of 50 to 500 g/L, more preferably a viscosity of 100-900 cP and a content of VOCs of 50 to 420 g/L and more preferably a viscosity of 150-800 cP and a content of VOCs of 50 to 390 g/L.

The antifouling coating composition and paint of the invention can be applied to a whole or part of any article surface which is subject to fouling. The surface may be permanently or intermittently underwater (e.g. through tide movement, different cargo loading or swell). The article surface will typically be the hull of a vessel or surface of a fixed marine object such as an oil platform or buoy. Application of the coating composition and paint can be accomplished by any convenient means, e.g. via painting (e.g. with brush or roller) or more preferably spraying the coating onto the article. Typically the surface will need to be separated from the seawater to allow coating. The application of the coating can be achieved as conventionally known in the art. After the coating is applied, it is preferably dried.

The invention will now be described by the following non-limiting examples wherein:

EXAMPLES

Preparation and characterisation of polymers Determination of polymer solution viscosity

The viscosity of the polymer solutions was determined in accordance with ASTM D2196-15 Test method A using a Brookfield DV-I viscometer with LV-2 or LV-4 spindle at 12 rpm. The polymers were tempered to 23.0°C ± 0.5°C before the measurements.

Determination of solids content of the polymer solutions

The solids content of the polymer solutions was determined in accordance with ISO 3251 :2008. A test sample of 0.4 g ± 0.1 g was taken out and dried in a ventilated oven at 150°C for 30 minutes. The weight of the residual material is considered to be the non-volatile matter (NVM). The non-volatile matter content is expressed in weight percent. The result given is the average of three parallels.

Determination of polymer average molecular weights distribution

The polymers were characterised by Gel Permeation Chromatography (GPC) measurement. The molecular weight distribution (MWD) was determined using a Malvern Omnisec Resolve and Reveal system with two PLgel 5 μηη Mixed-D columns from Agilent in series. The columns were calibrated by conventional calibration using narrow polystyrene standards. The analysis conditions were as set out in the table below. Detector Rl

Cell volume 12 μΙ

Column Set Agilent PLgel 5 μηι Mixed-D, 2 columns in series

Mobile Phase THF

Flow rate 1 ml/min

Injection volume 100 μΙ

Autosampler Temperature 25 °C

Column Oven Temperature 35 °C

Detector Oven 35 °C

Temperature

Data Processing Omnisec 5.1

Calibration standards Agilent Polystyrene Medium EasiVials (4 ml)

Red, Yellow and Green

Samples were prepared by dissolving an amount of polymer solution corresponding to 25 mg dry polymer in 5 ml. THF. The samples were kept for a minimum of 3 hours at room temperature prior to sampling for the GPC measurements. Before analysis the samples were filtered through 0.45 μηι Nylon filters. The weight- average molecular weight (Mw) and the polydispersity index (PDI), given as Mw/Mn, is reported.

Determination of the glass transition temperature

The glass transition temperature (Tg) was obtained by Differential Scanning

Calorimetry (DSC) measurements. The DSC measurements were performed on a TA Instrument DSC Q200. Dry polymer samples were prepared by making drawdown on a glass panel using a film applicator with 100 μηι gap size. The glass panels were dried at room temperature for at least 24 hour with subsequent drying at 50 °C for 24 hours. Approximately 10 mg dry polymer material was collected from the glass panels and transferred to an aluminium pan. The measurements were done in open aluminium pans with an empty pan as reference. Scans were recorded at a heating rate of 10°C/min and cooling rate of 10°C/min in a temperature range from -50 °C to 120 °C. The data were processed using Universal Analysis software from TA Instruments. The inflection point of the glass transition range, as defined in ASTM E1356-08, of the second heating is reported as the Tg of the polymers. General procedure for preparation of copolymer solution S-1 to S-9

A quantity of solvent was charged to a temperature-controlled reaction vessel equipped with a stirrer, a condenser, a nitrogen inlet and a feed inlet. The reaction vessel was heated and maintained at the reaction temperature of 85 °C. A pre-mix of monomers, initiator and solvent was prepared. The pre-mix was charged to the reaction vessel at a constant rate over 2 hours under a nitrogen atmosphere. After a further 1 hour, post-addition of a boost initiator solution was added. The reaction vessel was maintained at the reaction temperature of 85 °C for a further 2 hours. The temperature was then increased to 1 10 °C and maintained for a further 30 minutes. The thinning solvent was added to the reactor and the copolymer solution was then cooled to room temperature.

The ingredients of the compositions, given as parts by weight, and the properties of the copolymer solutions are presented in Table 1 .

Table 1

Preparation and testing of antifouling coating formulations

Determination of paint viscosity using Cone and Plate viscometer

The viscosity of the antifouling coating compositions were determined according to ISO 2884-1 :1999 using a Cone and Plate viscometer set at a temperature of 23 °C, working at a shear rate of 10000 s ^"1 and providing viscosity measurement range of 0-10 P. The result given is the average of three measurements.

Determination of paint consistency using Stormer-type viscometer

The consistency of the antifouling paint compositions was determined according to ASTM D562-10(2014) Method B using a digital Stormer-type viscometer. The measurement was done on samples in 500 mL container at 23 °C.

Determination of VOC

The VOC (g/L) of the antifouling coating compositions was calculated according to ASTM D5201 -01 .

Accelerated storage stability testing of paints

The storage stability of the antifouling coating compositions were determined under the conditions described in ASTM D1849-95(2014). The samples were stored in 250 mL containers at 52 °C. After storage, the samples were cooled to room temperature before the containers were opened. The consistency of the paints was evaluated. Liquid samples were stirred to homogenous quality and the viscosities were recorded using a Cone and Plate viscometer. Storage for 1 month at 52 °C simulates some of the effects of storage for 6 months to 1 year at 23 °C.

General procedure for preparation of antifouling coating compositions

The components were mixed in the proportions given in Tables 3-1 to 3-3 and Table 4. The amounts are given in parts by weight. Table 4 describes comparative compositions. The mixture was dispersed in the presence of an appropriate amount of glass beads (3-4 mm in diameter) in a 1 L container using a vibrational paint shaker for 15 minutes. The paint was transferred to 250 mL containers for storage stability testing.

The properties of the polar solvents employed in the antifouling coating compositions are summarised in Table 2 below. The Hansen solubility properties were taken from HSPiP (Hansen Solubility Parameters in Practice) software 4th Edition 4.1 .07.

Table 2

Table 3-1

Table 3-1 continued

Table 3-2

Table 3-2 (continued)

PB-11 PB-12 PB-13

Silyl copolymer S-1 - - -

S-2 - - -

S-3 - - -

S-5 - - -

S-7 28.0 - -

S-8 - 20.0 20.0

Co-binders Gum rosin 6.0 8.0 8.0

Poly(n-butyl acrylate) - 2.0 2.0

Biocides Copper(l) oxide - - -

Copper(l) thiocyanate - 25.0 25.0

Copper pyrithione - - -

Zinc pyrithione 3.0 5.0 5.0

Tralopyril 5.0 3.0 3.0

Pigment and Naphtol red 0.5 - - extenders Iron oxide red 1.0 5.0 5.0

Titanium dioxide - - -

Talc 6.0 3.0 3.0

Feldspar 10.0 - -

Zinc oxide 23.0 7.0 7.0

Additives Polyamide wax (20% in xylene) 0.5 2.0 2.0

Oxidized poly(ethylene oxide) wax (25% in xylene) 0.5 - -

Tetraethoxysilane 1.0 1.0 1.0

Calcium sulphate hemihydrate - - -

Sylosive A4 - - -

Polar solvents Butyl acetate 10.0 10.0 15.0

1-Methoxy-2-propyl acetate - - -

Other solvents Xylene 10.0 9.0 4.0

Sum 99.5 100.0 100.0 wt% polar solvent of total solvent 18 % 34 % 51 %

Calculated VOC (g/L) 394 400 400

Storage stability; Start 285 197 189 Cone & Plate 1 week 321 247 258 viscosity (cP) 2 weeks 352 275 309

3 weeks 368 319 367

4 weeks 523 407 462 Table 3-3

PC-1 PC-2 PC-3 PC-4

Silyl copolymer S-1 26.5 - - 26.5

S-2 - 24.3 - -

S-7 - - - -

S-8 - - 20.0 -

S-9 - - - -

Co-binders Gum rosin 4.5 4.5 8.0 4.5

Poly(n-butyl acrylate) - - 2.0 -

Biocides Copper(l) oxide 35.0 35.0 - 35.0

Copper(l) thiocyanate - - 25.0 -

Copper pyrithione 3.0 3.0 5.0 3.0

Zinc pyrithione - - - -

Zineb - - - -

Tralopyril 3.0 3.0 3.0 3.0

Pigment and Iron oxide red 2.0 2.0 5.0 2.0 extenders Titanium dioxide 1.0 1.0 - 1.0

Talc 6.0 6.0 3.0 6.0

Dolomite - - - -

Zinc oxide 6.0 6.0 7.0 6.0

Additives Polyamide wax (20% in xylene) 1.0 1.0 2.0 1.0

Oxidized poly( ethylene oxide) wax

(25% in xylene) 0.5 0.5 - 0.5

Tetraethoxysilane 0.5 0.5 1.0 0.5

Polar solvents 1 -Methoxy-2-propanol 5.0 1.0 5.0 -

1 ,3-Dioxolane - - - 5.0

Other solvents Xylene 6.0 12.2 14.0 6.0

Sum 100.0 100.0 100.0 100.0 wt% polar solvent of total solvent 21 % 4 % 17 % 21 %

Calculated VOC (g/L) 409 406 401 414

Storage stability; Start 392 449 259 467 Cone & Plate 1 week 403 505 350 499 viscosity (cP) 2 weeks 458 541 461 525

3 weeks 515 540 684 557

4 weeks 552 569 945 623 Table 4

Antifouling coating compositions PA1 -PA17, PB1-13 and PC1 -4 all comprise a silyl (meth)acrylate, tralopyril and at least 2.5 wt% of polar solvent (either a ketone, ester or secondary alcohol). All of these coating compositions are stable to storage. Thus even after storage for 4 weeks in accelerated storage conditions, the compositions have not formed a gel which indicates that they are still applicable to a surface by spraying.

In contrast comparative example C-1 , which comprises silyl (meth)acrylate and tralopyril, but lacks a polar solvent, forms a gel after 1 week of storage. This demonstrates that it is the addition of the polar solvent to the composition which provides the storage stability.

Similarly comparative example C-3, which comprises silyl (meth)acrylate, tralopyril and only 2 wt% polar solvent, based on the total weight of solvent, forms a gel after 1 week of storage in accelerated conditions. In contrast PC-2 and PC-3, comprising 4 wt% and 9 wt% of polar solvent, based on the total weight of solvent, are stable to storage.

Comparative example C-2 which comprises silyl (meth)acrylate, but lacks tralopyril and polar solvent, is stable during storage. This shows that it is the combination of tralopyril and silyl (meth)acrylate which causes instability in antifouling compositions during storage.

Preparation of antifouling coating composition

An antifouling coating composition was prepared using a dissolver. 120 g copper pyrithione, 500 g silyl (meth)acrylate polymer solution S-2, 300 g gum rosin solution (60% in xylene) and 120 g methyl isoamyl ketone were mixed in a 3 L paint container. 1400 g copper(l) oxide, 240 g talc, 240 g zinc oxide, 80 g iron oxide red, 40 g titanium dioxide, 20 g oxidized polyether wax (25% in xylene) and 20 g tetraethoxysilane were added. The mixture was dispersed at high speed until the mill base had a fineness of grind of 40 μηι and a temperature of 55°C. 470 g silyl (meth)acrylate polymer solution S-2, 40 g polyamide wax (20% in xylene) and 170 g xylene were added under stirring. The mixture was cooled and a pre-mix of 120 g tralopyril and 120 g methyl isoamyl ketone was added. The paint was cooled to room temperature and transferred to smaller containers for viscosity measurements and storage stability testing. The viscosity was measured the next day.

The paint composition had a calculated VOC of 403 g/L and a measured Stormer viscosity of 86 KU and a Cone and Plate viscosity of 369 cP.