GB2576431A

GB2576431A - Antifouling Composition

Info

Publication number: GB2576431A
Application number: GB1911800.9A
Authority: GB
Inventors: Risberg Erik; Hensen Terje; Dahling Marit
Original assignee: Jotun AS
Current assignee: Jotun AS
Priority date: 2018-08-17
Filing date: 2019-08-16
Publication date: 2020-02-19
Anticipated expiration: 2039-08-16
Also published as: KR20200020605A; SG10201906899YA; GB201813454D0; CN110835486B; JP7427391B2; CN110835486A; GB2576431B; JP2020026533A; DE102019121252A1; GB201911800D0

Abstract

An antifouling coating composition comprises a binder system which includes (A) a first silyl ester copolymer comprising a triisopropylsilyl methacrylate monomer, (B) a second silyl ester copolymer comprising a triisopropylsilyl acrylate monomer, and (C) 5 to 40 wt.% monocarboxylic acid or a derivative thereof, wherein components (A) and (B) are different and the weight ratio of (A):(B) is 55:45 to 95:5. The acid or derivative thereof may be a C6-20 cyclic monocarboxylic acid, such as rosin. Copolymers (A) or (B) may comprise a hydrophilic monomer, such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, or tetrahydrofurfuryl (meth)acrylate. The binder system preferably comprises 20-70 wt.% copolymer (A) and 2-45 wt.% copolymer (B) on a dry solids basis. The composition may contain a biocide and less than 15 wt.% silyl ester copolymers other than (A) and (B). When combined, (A) and (B) may have a glass transition temperature of more than 10ºC and less than 70ºC.

Description

Antifouling Composition

Field of the Invention

The present invention relates to marine antifouling coating compositions, more specifically to marine antifouling coating compositions comprising a blend of a silyl ester copolymer comprising triisopropylsilyl methacrylate as a monomer with a silyl ester copolymer comprising triisopropylsilyl acrylate as a monomer. The composition additionally contains a monocarboxylic acid or derivative thereof. The invention further relates to a method of protecting objects from fouling, and to objects coated with the antifouling composition of the invention.

Background of invention

Surfaces that are submerged in seawater are subjected to fouling by marine organisms such as green and brown algae, barnacles, mussels, tube worms and the like. On marine constructions such as vessels, oil platforms, buoys, etc. such fouling is undesired and has economic consequences. The fouling may lead to biological degradation of the surface, increased load and accelerated corrosion. On vessels the fouling will increase the frictional resistance which will cause reduced speed and/or increased fuel consumption.

To prevent settlement and growth of marine organisms antifouling paints are used. These paints generally comprise a film-forming binder, together with different components such as pigments, fillers, additives and solvents together with biologically active substances (biocides). Biocides can be broadly divided into those active against soft fouling, such as green and brown algae, grass, slime and those active against hard fouling, such as barnacles, mussels, tube worms etc.

Commercial vessels (e.g. container ships, bulk carriers, tankers, passenger ships) often operate in different waters, in different trade, with different activity, including idle periods. The antifouling coating should provide good fouling protection under all those conditions. Typical service intervals for commercial vessels are from 30 to 90 months. Maintenance of submerged objects is costly, so the applied antifouling coatings should be effective for the specified service interval. It requires a controlled degradation of the coating film giving constant release of biocides to protect the object through the full service interval and under various sailing conditions.

This controlled degradation can best be obtained by using a self-polishing antifouling coating having a controlled polishing rate. Too fast polishing will lead to a rapid consumption of the coating film, resulting in an unprotected surface. Too slow polishing will lead to insufficient release of the biocide, which is vital for effective protection from fouling. A controlled degradation over the life time will give a constant release of biocides and thereby good fouling protection. The most successful self-polishing antifouling coatings products on the market are using silyl ester copolymers as binders. These are copolymers made by copolymerizing either triisopropyl silyl acrylate (TIPSA) or triisopropyl silyl methacrylate (TIPSMA).

In addition to these demands, the coating industry is constantly faced with stricter VOC regulations, which limits the amount of organic solvents that can be used in antifouling paints. The most common application methods for antifouling coating are airless spray, brush or roller. It is important that the paint can be applied by standard techniques which in turn means coating compositions and paints having a certain viscosity level, whilst minimising their VOC content and still achieving satisfactory application properties. The VOC limits may be exceeded if additional solvent must be added to reduce the viscosity at the point of application. Paint application is a high shear process. It is therefore recommended to use high shear Cone and Plate viscometer that apply a shear rate of 10 000 s-l (ISO 2884) or 12 000 s-l (ASTM D4287) to measure the coating viscosity. The method applies high shear to the paint which is representative of the shearing conditions under application of paint by brushing, rolling and spraying.

It is a challenge to find coating compositions which comply with the ever tightening VOC regulations and which also have controlled polishing properties, good mechanical properties and exhibit good fouling protection.

TIPSMA copolymers provide antifouling coatings with good mechanical properties, but limited antifouling performance due to slower polishing rates compared to TIPSA copolymers. TIPSA copolymers provide good static performance but are more prone to mechanical failure, such as cracking. Previous strategies to try to balance the mechanical properties with the antifouling performance have been to employ silyl acrylic copolymers which contain structural units derived from both TIPSMA and TIPSA as described in, for example, EP 2781567.

However, there are limitations on the reduction of VOC in order to maintain good application properties. The TIPSMA copolymers generally exhibit higher solution viscosity than TIPSA copolymers.

It is desirable to have an antifouling coating formulation with a low content of VOCs. The present inventors have found that by using a mixture of at least one TIPSMA copolymer and at least one TIPSA copolymer it is possible to achieve an antifouling coating having reduced VOC and good application properties and at the same time having good mechanical properties and providing good fouling protection. A mixture of at least one TIPSMA copolymer and at least one TIPSA copolymer gives a significantly lower viscosity of the coating composition compared to using a copolymer comprising both TIPSMA and TIPSA monomer units.

Summary of invention

In one aspect, the invention relates to an antifouling coating composition comprising a binder system which comprises:

(A) a silyl ester copolymer comprising a triisopropylsilyl methacrylate monomer;

(B) a silyl ester copolymer comprising a triisopropylsilyl acrylate monomer; and (C) 5 to 40 wt% of a monocarboxylic acid or derivative thereof;

wherein components (A) and (B) are different and the weight ratio of (A):(B) is in the range 55:45 to 95:5.

In another aspect, the invention provides a process for protecting an object from fouling, said process comprising coating at least a part of said object which is subject to fouling with an antifouling coating composition as defined herein.

The invention also relates to objects coated with the antifouling coating composition as defined herein.

Definitions

The terms “marine antifouling coating composition”, “antifouling coating composition” or simply “coating composition” refer to a composition that, when applied to a surface, prevents or minimises growth of marine organisms on the surface.

The term “hydrocarbyl group” refers to any group containing C atoms and H atoms only and therefore covers alkyl, alkenyl, aryl, cycloalkyl, aiylalkyl groups and so on.

The term “acrylic copolymer” refers to a copolymer comprising repeating units derived from (meth)aciylate monomers. Generally an acrylic copolymer will comprise at least 80 wt% of the repeating units derived from (meth)acrylate monomers, i.e. acrylate and/or methacrylate monomers.

The term “(meth)acrylate” means a methacrylate or acrylate.

As used herein the term “monocarboxylic acid” refers to a compound comprising one -COOH group.

As used herein the term “resin acid” refers to a mixture of carboxylic acids present in resins.

The term “rosin” used in the text which follows is being used to cover “rosin or derivatives thereof’.

The term “binder” defines part of the composition which includes the silyl ester copolymers and any other polymers, resins or components which together form a matrix giving substance and strength to the composition. Typically, the term “binder” used herein means the silyl ester copolymers together with the monocarboxylic acid, i.e. components (A), (B) and (C) as defined herein.

The term “Tg” means glass transition temperature.

Where a wt% of a given monomer is given, the wt% is relative to the sum total (weight) of each monomer present in the copolymer.

The term “wt% based on the total weight of the composition” refers to the wt% of a component present in the final, ready to use, composition, unless otherwise specified.

Detailed description of invention

The invention relates to a new antifouling coating composition comprising a binder, which contains a mixture of (A) a silyl ester copolymer comprising a triisopropylsilyl methacrylate monomer, (B) a silyl ester copolymer comprising a triisopropyl silyl acrylate monomer and (C) a monocarboxylic acid or derivative thereof.

(A) Silyl ester copolymer comprising triisopropylsilyl methacrylate (TIPSMA) monomer

The silyl ester copolymer (A) contains a monomer of triisopropyl silyl methacrylate. Typically, the weight percentage of the triisopropyl silyl methacrylate monomer is in the range 20 to 80 wt%, such as 30 to 70 wt%, relative to the total weight of the silyl ester copolymer as a whole. Additional silyl ester (meth)acrylate monomers, hydrophilic (meth)acrylate monomers, and/or non-hydrophilic (meth)acrylate monomers may additionally be present as described herein. In one embodiment, the silyl ester copolymer includes at least the monomers triisopropyl silyl methacrylate and a hydrophilic (meth)acrylate.

In a particularly preferable embodiment, the silyl ester copolymer (A) comprises as monomers:

(a) triisopropyl silyl methacrylate;

(b) a compound of Formula (I)

2 wherein R is hydrogen or methyl, R is a cyclic ether (such as oxolane, oxane, dioxolane, dioxane optionally alkyl substituted) and X is a C1-C4 alkylene;

and/or a compound of Formula (II)

4 wherein R is hydrogen or methyl, and R is a C3-Cl8 substituent with at least one oxygen or nitrogen atom, preferably at least one oxygen atom; and optionally (c) one or more monomers of Formula (III)

R⁵

o (III) wherein R⁵ is hydrogen or methyl, and R⁶ is a C1-C8 hydrocarbyl.

Monomers

In one embodiment, the silyl ester copolymer (A) includes at least the monomers triisopropyl silyl methacrylate (a) and at least one hydrophilic monomer (b).

Where a wt% of a given monomer in the silyl ester copolymer (A) is given, the wt% is relative to the sum total (weight) of each monomer present in the copolymer. Thus, if triisopropyl silyl methacrylate (a) and hydrophilic (meth)acrylate monomer (b) are the only monomers in the silyl ester copolymer, the wt% of triisopropyl silyl methacrylate is calculated as [triisopropyl silyl methacrylate (a) (weight) / (triisopropylsilyl methacrylate (a) (weight) + hydrophilic (meth)acrylate monomer (b) (weight))] x 100%. If only triisopropylsilyl methacrylate (a), hydrophilic (meth)acrylate monomer (b) and non-hydrophilic (meth)acrylate (c) are present, the wt% of triisopropylsilyl methacrylate is calculated as [triisopropylsilyl methacrylate (a) (weight) / (triisopropylsilyl methacrylate (a) (weight) + hydrophilic (meth)acrylate monomer (b) (weight) + non-hydrophilic (meth)acrylate (c) (weight))] x 100%.

The copolymer (A) preferably comprises >80 wt%, preferably >90 wt%, more preferably >95 wt%, especially >98 wt% of the combination of triisopropylsilyl methacrylate (a), hydrophilic (meth)acrylate monomer(s) (b) and non-hydrophilic (meth)acrylate monomer(s) (c).

Component (a) is triisopropylsilyl methacrylate, which preferably forms 20 to 80 wt% of the copolymer, preferably 30 to 75 wt%, especially 40 to 70 wt%, more especially 45 to 65 wt%.

Component (b) (total) preferably forms 1 to 50 wt% of the copolymer, preferably 3 to 40 wt% of the copolymer, especially 4 to 35 wt% of the copolymer, more especially 5 to 30 wt%. These wt% values refer to the total of component (b) monomers present.

The ratio (a):(b) (weight/weight) is preferably in the range of 40:60 to 99:1, preferably in the range of 50:50 to 95:5, especially in the range of 55:45 to 92:8, most preferably in the range of 60:40 to 90:10. It is preferred that the weight fraction of (a) in the copolymer is greater than that of component (b).

The amount of (a)+(b) in the copolymer (A) is preferably at most 95 wt%, such as at most 90 wt%, especially at most 85 wt%. The amount of (a)+(b) in the copolymer may be in the range of 30-95 wt% or 40-85 wt%.

Hydrophilic (meth)acrylate monomer! s) component !b)

In certain embodiments, the silyl ester copolymer contains at least one monomer of Formula (I)

2 wherein R is hydrogen or methyl, R is a cyclic ether (such as oxolane, oxane, dioxolane, dioxane optionally alkyl substituted) and X is a C1-C4 alkylene, preferably a C1-C2 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, C1-C6 alkyl group. That substituent group might be at any position on the ring including the position that binds to the X group.

Suitable compounds of Formula (I) include tetrahydrofurfuryl acrylate, tetrahydrofiirfuryl methacrylate, isopropylideneglycerol methacrylate, glycerolformal methacrylate and cyclic trimethylolpropane formal acrylate.

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

In a further embodiment, the copolymer (A) may include one or more monomers of Formula (II):

4 wherein R is hydrogen or methyl, and R is a C3-C18 substituent containing at least one oxygen or nitrogen atom, preferably at least one oxygen atom.

As indicated in the above formula, the term “hydrophilic (meth)acrylate” requires the R⁴ group in Formula (II) to include at least one oxygen or nitrogen atom, preferably at least one oxygen atom. As explained in detail below, additional non-hydrophilic (meth)acrylate monomers of Formula (III) may also be present, in which the R⁶ unit consists of C and H atoms only.

In an embodiment, the silyl ester copolymer (A) contains at least one monomer of Formula (II) above, in which the R⁴ group is of formula -(CFFCFFOlmR , where R is a Cl-CIO hydrocarbyl substituent, preferably a Cl-CIO alkyl or a C6-C10 aryl substituent, and m is an integer in the range of 1 to 6, preferably 1 to 3. Preferably R is of formula -(CFFCFFOlm-R , where R is an alkyl substituent, preferably methyl or ethyl, and m is an integer in the range of 1 to 3, preferably 1 or

2.

In an embodiment, the silyl ester copolymer (A) includes one or more of 2methoxyethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl acrylate, 2ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethyl acrylate, 2-(2methoxyethoxy)ethyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2ethoxyethoxy)ethyl methacrylate, oligo(ethylene glycol) methyl ether acrylate and oligo(ethylene glycol) methyl ether methacrylate.

Particularly preferred monomer(s) (b) include 2-methoxyethyl acrylate, 2methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2-ethoxyethoxy)ethyl methacrylate, tetrahydrofurfuryl acrylate, and tetrahydrofurfuryl methacrylate.

As used herein, Formula (I) and Formula (II) defines a “polar” (meth)acrylate monomer or “hydrophilic” (meth)acrylate monomer. The use of these monomers with triisopropylsilyl methacrylate ensures the formation of a binder that has a controlled degradation.

It is preferred if the silyl ester copolymer (A) comprises a monomer of Formula (I) or a monomer of Formula (II). It is generally not preferred to have a monomer from both these formulae present.

Additional non-hydrophilic (meth)acrylate monomer(s) (c)

The silyl ester copolymer (A) may include one or more additional nonhydrophilic (meth)acrylate monomers of Formula (III)

R⁵

O (III) wherein R⁵ is hydrogen or methyl, and R⁶ is a C1-C8 hydrocarbyl substituent, preferably a C1-C8 alkyl substituent, most preferably methyl, ethyl, n-butyl or 2ethylhexyl. Monomers according to Formula (III) are referred to as “nonhydrophilic” monomers herein. Preferable “non-hydrophilic” monomers include ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate and butyl methacrylate.

In all embodiments of the invention the silyl ester copolymer (A) preferably includes at least one additional non-hydrophilic methacrylate and/or non-hydrophilic acrylate monomer. Where one or more non-hydrophilic (meth)acrylate monomers are present, the sum of these non-hydrophilic (meth)acrylate monomers in the silyl ester copolymer is preferably at most 60 wt%, preferably no more than 55 wt%, such as in the range of 5 to 55 wt%, especially in the range of 10 to 50 wt%.

In a preferred embodiment, the monomers triisopropyl silyl methacrylate (a), component (b) and any non-hydrophilic (meth)acrylate monomer(s) according to Formula (III) together form >80wt%, preferably >90 wt%, especially >95 wt%, more especially >98wt% of the monomers in the silyl ester copolymer (A).

In a preferred embodiment, the silyl ester copolymer (A) includes one or more of the non-hydrophilic monomers methyl methacrylate and/or n-butyl acrylate.

In all embodiments of the invention it is preferred that methyl methacrylate is included. Where present, methyl methacrylate is preferably present in an amount of 2 to 50 wt%, preferably 5 to 40 wt% of the copolymer (A). In a preferred embodiment triisopropyl silyl methacrylate (a), component (b) and methyl methacrylate together form >50 wt%, preferably >65 wt%, especially >80 wt% of the monomers in the silyl ester copolymer (A).

Where present, n-butyl acrylate is preferably present in an amount of 1 to 30 wt%, especially 2 to 20 wt%, more especially 3 to 15 wt%.

The silyl ester copolymer (A) may include additional ethylenically unsaturated monomers. Representative examples of suitable ethylenically unsaturated monomers include styrene, vinyl acetate, triisopropyl silyl acrylate, 2(trimethylsiloxy)ethyl methacrylate, zinc (meth)acrylate, zinc acetate (meth)acrylate and zinc neodecanoate (meth)acrylate. Where present, any additional ethylenically unsaturated monomer preferably forms no more than 20 wt% of the copolymer, preferably no more than 10 wt% of the copolymer.

(B) Silyl ester copolymer comprising triisopropylsilyl acrylate (TIPSA) monomers

The silyl ester copolymer (B) contains a monomer of triisopropylsilyl acrylate. Typically, the weight percentage of the triisopropyl silyl acrylate monomer is in the range 20 to 80 wt%, such as 30 to 70 wt%, relative to the total weight of the silyl ester copolymer as a whole. Additional silyl ester (meth)acrylate monomers, hydrophilic (meth)acrylate monomers, and/or non-hydrophilic (meth)acrylate monomers may additionally be present as described herein. In one embodiment, the silyl ester copolymer (B) includes at least the monomers triisopropylsilyl acrylate and a hydrophilic (meth)acrylate.

In a particularly preferable embodiment, the silyl ester copolymer (B) comprises as monomers:

(a) triisopropyl silyl acrylate;

(b) a compound of Formula (I)

(I)

and/or a compound of Formula (II)

R³

⁰ (Π) wherein R is hydrogen or methyl, and R is a C3-Cl8 substituent with at least one oxygen or nitrogen atom, preferably at least one oxygen atom; and optionally (c) one or more monomers of Formula (III)

O (III) wherein R⁵ is hydrogen or methyl, and R⁶ is a C1-C8 hydrocarbyl.

Monomers

In one embodiment, the silyl ester copolymer (B) includes at least the monomers triisopropylsilyl acrylate (a) and at least one hydrophilic monomer (b).

Where a wt% of a given monomer in the silyl ester copolymer (B) is given, the wt% is relative to the sum total (weight) of each monomer present in the copolymer. Thus, if triisopropylsilyl acrylate (a) and hydrophilic (meth)acrylate monomer (b) are the only monomers in the silyl ester copolymer, the wt% of triisopropylsilyl acrylate is calculated as [triisopropylsilyl acrylate (a) (weight) / (triisopropylsilyl acrylate (a) (weight) + hydrophilic (meth)acrylate monomer (b) (weight))] x 100%. If only triisopropylsilyl acrylate (a), hydrophilic (meth)acrylate monomer (b) and non-hydrophilic (meth)acrylate (c) are present, the wt% of triisopropylsilyl acrylate is calculated as [triisopropylsilyl acrylate (a) (weight) / (triisopropylsilyl acrylate (a) (weight) + hydrophilic (meth)acrylate monomer (b) (weight) + non-hydrophilic (meth)acrylate (c) (weight))] x 100%.

The copolymer preferably comprises >80 wt%, preferably >90 wt%, more preferably >95 wt%, especially >98 wt% of the combination of triisopropylsilyl acrylate (a), hydrophilic (meth)acrylate monomer(s) (b) and non-hydrophilic (meth)acrylate monomer(s) (c).

Component (a) is triisopropylsilyl acrylate, which preferably forms 20 to 80 wt% of the copolymer, preferably 30 to 75 wt%, especially 40 to 70 wt%, more especially 45 to 65 wt%.

Component (b) (total) preferably forms 1 to 40 wt% of the copolymer, preferably 3 to 30 wt% of the copolymer, especially 4 to 25 wt% of the copolymer, more especially 5 to 20 wt%. These wt% values refer to the total of component (b) monomers present.

The ratio (a):(b) (weight/weight) is preferably in the range of 50:50 to 99:1, preferably in the range of 60:40 to 95:5, especially in the range of 70:30 to 93:7, most preferably in the range of 75:25 to 92:8. It is preferred that the weight fraction of (a) in the copolymer is greater than that of component (b).

The amount of (a)+(b) in the copolymer is preferably at most 95 wt%, such as at most 90 wt%, especially at most 85 wt%. The amount of (a)+(b) in the copolymer may be in the range of 30-95 wt% or 40-85 wt%.

Hydrophilic (meth (acrylate monomerCs) component (b)

In certain embodiments, the silyl ester copolymer (B) contains at least one monomer of Formula (I)

R¹ (I)

In a further embodiment, the copolymer (B) may include one or more monomers of Formula (II):

(II)

In an embodiment, the silyl ester copolymer (B) contains at least one monomer of Formula (II) above, in which the R⁴ group is of formula -(CH2CH₂O)_mR , where R is a Cl-CIO hydrocarbyl substituent, preferably a Cl-CIO alkyl or a C6-C10 aryl substituent, and m is an integer in the range of 1 to 6, preferably 1 to 3. Preferably R is of formula -(CH2CH₂O)_m-R , where R is an alkyl substituent, preferably methyl or ethyl, and m is an integer in the range of 1 to 3, preferably 1 or 2.

In an embodiment, the silyl ester copolymer (B) includes one or more of 2methoxyethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl acrylate, 2ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethyl acrylate and 2-(2methoxyethoxy)ethyl methacrylate 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2ethoxyethoxy)ethyl methacrylate, oligo(ethylene glycol)methyl ether acrylate and oligo(ethylene glycol)methyl ether methacrylate.

As used herein, Formula (I) and Formula (II) defines a “polar” (meth)acrylate monomer or “hydrophilic” (meth)aciylate monomer. The use of these monomers with triisopropyl silyl acrylate ensures the formation of a binder that has a controlled degradation.

It is preferred if the silyl ester copolymer (B) comprises a monomer of Formula (I) or a monomer of Formula (II). It is generally not preferred to have a monomer from both these formulae present.

Additional non-hydrophilic (meth)acrylate monomer(s) (c)

The silyl ester copolymer (B) may include one or more additional nonhydrophilic (meth)aciylate monomers of Formula (III)

R⁵

R⁶

Ο (ΠΙ) wherein R⁵ is hydrogen or methyl, and R⁶ is a C1-C8 hydrocarbyl substituent, preferably a C1-C8 alkyl substituent, most preferably methyl, ethyl, n-butyl or 2ethylhexyl. Monomers according to Formula (III) are referred to as “nonhydrophilic” monomers herein. Preferable “non-hydrophilic” monomers include ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate and butyl methacrylate.

In all embodiments of the invention the silyl ester copolymer (B) preferably includes at least one additional non-hydrophilic methacrylate and/or non-hydrophilic acrylate monomer. Where one or more non-hydrophilic (meth)acrylate monomers are present, the sum of these non-hydrophilic (meth)acrylate monomers in the silyl ester copolymer is preferably at most 60 wt%, preferably no more than 55 wt%, such as in the range of 5 to 55 wt%, especially in the range of 10 to 50 wt%.

In a preferred embodiment, the monomers triisopropyl silyl acrylate (a), component (b) and any non-hydrophilic (meth)acrylate monomer(s) according to Formula (III) together form >80wt%, preferably >90 wt%, especially >95 wt%, more especially > 98 wt% of the monomers in the silyl ester copolymer (B).

In a preferred embodiment, the silyl ester copolymer (B) includes one or more of the non-hydrophilic monomers methyl methacrylate and/or n-butyl acrylate.

In all embodiments of the invention it is preferred that methyl methacrylate is included. Where present, methyl methacrylate is preferably present in an amount of 2 to 60 wt%, preferably 5 to 50 wt% of the copolymer. In a preferred embodiment triisopropyl silyl acrylate (a), component (b) and methyl methacrylate together form >50 wt%, preferably >65 wt%, especially >80 wt% of the monomers in the silyl ester copolymer (B).

The silyl ester copolymer (B) may include additional ethylenically unsaturated monomers. Representative examples of suitable ethylenically unsaturated monomers include styrene, vinyl acetate, triisopropylsilyl methacrylate, 2-(trimethylsiloxy)ethyl methacrylate, zinc (meth)acrylate, zinc acetate (meth)acrylate and zinc neodecanoate (meth)acrylate. Where present, any additional ethylenically unsaturated monomer preferably forms no more than 20 wt% of the copolymer, preferably no more than 10 wt% of the copolymer.

Properties of the silyl ester copolymers (A) and (B)

The silyl ester copolymers (A) and (B) can be prepared using polymerization reactions known in the art. The silyl ester copolymers can 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, dispersion polymerization and suspension polymerization in a conventional way or by controlled polymerization techniques. In preparing a coating composition using this silyl ester copolymer, the copolymer is preferably diluted with an organic solvent to give a polymer solution having an appropriate viscosity. From this standpoint, it is desirable to employ solution polymerization.

Examples of suitable initiators for free-radical polymerization include azo compounds such as dimethyl 2,2’-azobis(2-methylpropionate), 2,2'-azobis(2methylbutyronitrile), 2,2'-azobis(isobutyronitrile) and 1,1'azobis(cyanocyclohexane); and peroxides such as tert-amyl peroxypivalate, tertbutyl peroxy pivalate, tert-amyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, tert-butyl peroxydiethylacetate, tert-butyl peroxyisobutyrate, tert-butyl peroxybenozate, 1,1di(tert-amyl peroxy)cyclohexane, tert-amyl peroxy 2-ethylhexyl carbonate, tertbutylperoxy isopropyl carbonate, tert-butylperoxy 2-ethylhexyl carbonate, polyether poly-tert-butylperoxy carbonate, di-tert-butyl peroxide and dibenzoyl peroxide. These compounds may be used alone or in combinations of two or more thereof.

Examples of the organic solvent include aromatic hydrocarbons such as xylene, toluene, mesitylene; ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, methyl isoamyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone; esters such as butyl acetate, tert-butyl acetate, amyl acetate, isoamyl acetate, propyl propionate, n-butyl propionate, isobutyl isobutyrate, 2-methoxyethyl acetate, l-methoxy-2-propyl acetate; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dibutyl ether, dioxane, tetrahydrofuran, alcohols such as methyl isobutyl carbinol, benzyl alcohol; ether alcohols such as l-methoxy-2-propanol, l-propoxy-2propanol; aliphatic hydrocarbons such as white spirit, limonene. These solvents may be used alone or in combinations of two or more thereof.

The silyl ester copolymer may be a random copolymer, an alternate copolymer, a gradient copolymer or block copolymer. The copolymer is preferably a random copolymer.

The thus-obtained polymer containing organosilyl ester groups preferably has a weight-average molecular weight (Mw) from 5,000 to 100,000, preferably from 15,000 to 80,000, more preferably from 20,000 to 60,000. Mw is measured as described in the examples section.

The silyl ester copolymers (A) and (B) preferably each have a glass transition temperature (Tg) of at least 5 °C, preferably at least 10 °C, all values being measured according to the Tg test described in the examples section. Values less than 70 °C are preferred, such as less than 60 °C, e.g. less than 55 °C.

When combined, the blend of copolymers (A) and (B) preferably has a glass transition temperature (Tg) of less than 70 °C, preferably less than 60 °C, such as less than 55 °C, all values being measured according to the Tg test described in the examples section. Values more than 10 °C are preferred, such as more than 20 °C,

e.g. more than 25 °C.

The silyl ester copolymers (A) and (B) may be provided as a polymer solution, such as a xylene solution. The polymer solution is desirably regulated to have a solid content from 30 to 90 % by weight, preferably from 40 to 80 % by weight, more preferably from 45 to 75 % by weight.

The weight ratio of copolymer (A):(B) in the coating composition is in the range 55:45 to 95:5. Preferably, the ratio of (A):(B) is in the range 65:35 to 90:10.

The amount of silyl ester copolymer (A) present in the coating compositions of the invention is 20 to 90 wt% (dry solids), preferably 30 to 80 wt% (dry solids), more preferably 35 to 75 wt% (dry solids), based on the total weight of the binder system (dry solids).

The final antifouling coating composition of the invention preferably comprises 2 to 30 wt% (dry solids), more preferably 5 to 25 wt% (dry solids) of the silyl ester copolymer (A), based on the total coating composition.

The amount of silyl ester copolymer (B) present in the coating compositions of the invention is 2 to 45 wt% (dry solids), preferably 3 to 40 wt% (dry solids), more preferably 5 to 35 wt% (dry solids), based on the total weight of the binder system (dry solids).

The final antifouling coating composition of the invention preferably comprises 0.5 to 15 wt% (dry solids), more preferably 1 to 12 wt% (dry solids) of the silyl ester copolymer (B), based on the total coating composition.

It is within the ambit of the invention to employ more than one silyl ester copolymer (A) and/or more than one silyl ester copolymer (B), however it is preferred if a single copolymer (A) and a single copolymer (B) are used.

In one embodiment of the invention, the coating composition contains less than 15 wt%, preferably less than 10 wt%, such as less than 5 wt%, e.g. 0 wt% of a silyl ester copolymer other than copolymer (A) and (B) as defined herein.

(C) Monocarboxylic acid

The antifouling coating compositions of the present invention comprise a monocarboxylic acid or derivative thereof.

Monocarboxylic acids and derivatives of monocarboxylic acids have a number of properties that makes them applicable in antifouling coating compositions. They contribute to the controlled release of biocides, adjust the water solubility and mechanical properties of the antifouling coating, and reduce viscosity. They are readily available, and many of them originate from renewable, natural resources.

The monocarboxylic acid present in the antifouling coating composition of the present invention preferably comprises 5 to 50 carbon atoms, more preferably 10 to 40 carbon atoms and still more preferably 12 to 25 carbon atoms.

The monocarboxylic acid present in the antifouling coating composition of the present invention is preferably selected from a resin acid or derivative thereof, C6-C20 cyclic monocarboxylic acid, C5-C24 acyclic aliphatic monocarboxylic acid, C7-C20 aromatic monocarboxylic acid, a derivative of any of the monocarboxylic acids, and mixtures thereof.

Derivatives of monocarboxylic acid include metal salts of monocarboxylic acid, such as alkali metal carboxylate, alkaline earth metal carboxylate (e.g. calcium carboxylate, magnesium carboxylate) and transition metal carboxylate (e.g. zinc carboxylate, copper carboxylate). Preferably the metal carboxylate is a transition metal carboxylate, particularly preferably the metal carboxylate is a zinc carboxylate or copper carboxylate. The metal carboxylate may be added directly to the antifouling coating composition or be generated in situ in the antifouling coating composition.

Representative examples of resin acids include abietic acid, neoabietic acid, dehydroabietic acid, palustric acid, levopimaric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, communic acid and mercusic acid, secodehydroabietic acid. It will be appreciated that the resin acids are derived from natural sources and as such they typically exist as a mixture of acids. Resin acids are also referred to as rosin acids. Representative examples of sources of resin acids are gum rosin, wood rosin and tall oil rosin. Gum rosin, also referred to as colophony and colophonium, is particularly preferred. Preferred rosins are those comprising more than 85 % resin acids and still more preferably more than 90 % resin acids.

Commercial grades of rosin are often classified according to its colour by designation of letters on a colour scale XC (lightest), XB, XA, X, WW, WG, N, M, K, I, H, G, F, E, D (darkest) as specified in ASTM D509. Preferred colour grades for the compositions of the invention are X, WW, WG, N, Μ, K, I, and still more preferably WW. Commercial grades of rosin typically have an acid value from 155 to 180 mg KOH/g as specified in ASTM D465. Preferred rosin for the compositions of the invention has an acid value from 155 to 180 mg KOH/g, more preferred 160 to 175 mg KOH/g, even more preferred 160 to 170 mg KOH/g. Commercial grades of rosin typically have a softening point (Ring & Ball) of 70 °C to 80 °C as specified in ASTM E28. Preferred rosin for the compositions of the invention has a softening point of 70 °C to 80 °C, more preferred 75 °C to 80 °C

Representative examples of resin acid derivatives include partly hydrogenated rosin, fully hydrogenated rosin, disproportionated rosin, dihydroabietic acids, dihydropimaric acids and tetrahydroabietic acids.

Representative examples of C6-C20 cyclic monocarboxylic acids include naphthenic acid, l,4-dimethyl-5-(3-methyl-2-butenyl)-3-cyclohexen-l-yl-carboxylic acid, l,3-dimethyl-2-(3-methyl-2-butenyl)-3-cyclohexen-l-yl-carboxylic acid, 1,2,3trimethyl-5-(l-methyl-2-propenyl)-3-cyclohexen-l-yl-carboxylic acid, 1,4,5trimethyl-2-(2-methyl-2-propenyl)-3-cyclohexen-l-yl-carboxylic acid, 1,4,5trimethyl-2-(2-methyl-l-propenyl)-3-cyclohexen-l-yl-carboxylic acid, 1,5,6trimethyl-3-(2-methyl-1 -propenyl)-4-cyclohexen-1 -yl-carboxylic acid, 1 -methyl-4(4-methyl-3-pentenyl)-4-cyclohexen-l-yl-carboxylic acid, l-methyl-3-(4-methyl-3pentenyl)-3-cyclohexen-1 -yl-carboxylic acid, 2-methoxycarbonyl-3-(2-methyl-1 propenyl)-5,6-dimethyl-4-cyclohexen-l-yl-carboxylic acid, l-isopropyl-4-methylbicyclo[2,2,2]2-octen-5-yl-carboxylic acid, l-isopropyl-4-methyl-bicyclo[2,2,2]2octen-6-yl-carboxylic acid, 6-isopropyl-3-methyl-bicyclo[2,2,2]2-octen-8-ylcarboxylic acid and 6-isopropyl-3-methyl-bicyclo[2,2,2]2-octen-7-yl-carboxylic acid.

Representative examples of C5-C24 acyclic aliphatic monocarboxylic acids include Versatic™ acids, neodecanoic acid, 2,2,3,5-tetramethylhexanoic acid, 2,4dimethyl-2-isopropylpentanoic acid, 2,5-dimethyl-2-ethylhexanoic acid, 2,2dimethyloctanoic acid, 2,2-diethylhexanoic acid, pivalic acid, 2,2-dimethylpropionic acid, trimethylacetic acid, neopentanoic acid, 2-ethylhexanoic acid, isononanoic acid, 3,5,5-trimethylhexanoic acid, isopalmitic acid, isostearic acid, 16methylheptadecanoic acid and 12,15-dimethylhexadecanoic acid. The acyclic aliphatic monocarboxylic acid is preferably selected from liquid, acyclic C10-C24 monocarboxylic acids or liquid, branched C10-C24 monocarboxylic acids. It will be appreciated that many of the acyclic C10-C24 monocarboxylic acids may be derived from natural sources, in which case in isolated form they typically exist as a mixture of acids of differing chain lengths with varying degree of branching.

Preferably the monocarboxylic acid is gum rosin, derivatives of gum rosin, acyclic C10-C24 monocarboxylic acids, C6-C20 cyclic monocarboxylic acids or mixtures thereof. A mixture of acid preferably contains at least one resin acid, gum rosin or derivative of gum rosin. Gum rosin is most preferred.

In one embodiment, the derivative of the monocarboxylic acid is not a metal carboxylate.

The amount of monocarboxylic acid present in the compositions of the invention is 5 to 40 wt% (dry solids), preferably 10 to 35 wt% (dry solids), more preferably 15 to 30 wt% (dry solids), based on the total weight of the binder system.

The final antifouling coating composition of the invention preferably comprises 0.5 to 25 wt% (dry solids) of the monocarboxylic acid, such as 1 to 20 wt% (dry solids), in particular 2 to 18 wt% (dry solids) based on the total coating composition.

(D) Acrylic Copolymer

The coating compositions of the present invention may additionally comprise an acrylic copolymer (D) as part of the binder system. The term “acrylic copolymer” refers to copolymers comprising at least one monomer based on acrylic acid, methacrylic acid, esters of acrylic acid and esters of methacrylic acid. It is a requirement that the acrylic copolymer (D) is different to the copolymers (A) and (B) of the invention. Ideally, the acrylic copolymer (D) does not contain TIPSMA or TIPSA monomer units.

The acrylic copolymer preferably has a Tg below 30 °C, preferably below 20 °C, more preferred below 10 °C, even more preferred below 0°C, all values being measured according to the Tg test described in the examples section. It is envisaged that the use of an acrylic copolymer having a glass transition temperature (Tg) of less than 30 °C may further reduce the viscosity of the eventual antifouling coating composition and therefore reduces the solvent content that might be required.

A single acrylic copolymer may be employed as component (D).

Alternatively, a mixture of two or more acrylic polymers can be used.

In one embodiment, the acrylic copolymer contains (meth)acrylic acid units, more preferred having acid number below 60 mg KOH/g polymer, more preferred below 40 mg KOH/g polymer, even more preferred below 25 mg KOH/g polymer. Preferably the acid number is above 2 mg KOH/g polymer, such as above 5 mg KOH/g polymer. The acid number is measured as described in the examples section.

In one embodiment, the acrylic copolymer comprises 0.50-10 wt% of a carboxylic acid-containing monomer, based on the total weight of the acrylic copolymer.

In a particular preferable embodiment, the acrylic copolymer comprises as monomers:

i. at least one (meth)acrylate of Formula (IV):

wherein R⁸ is hydrogen or methyl, and R⁹ is a C1-C20 hydrocarbyl substituent; and ii. 0.5-10 wt% of at least one carboxylic acid-containing monomer, based on the total weight of the acrylic copolymer.

The combination of monomers defined under i. and ii. may make up at least 80 wt% of the acrylic copolymer such as at least 85 wt%, preferably at least 90 wt%, more preferably at least 95 wt%. In another particular embodiment, the combination of monomers defined under i. and ii. represent up to 95 wt% of the acrylic copolymer, such as up to 99 wt% of the acrylic copolymer.

To be clear, the “combination of monomers defined under i. and ii.” includes the possibility of having two or more monomers of Formula (IV) or two or more carboxylic acid-containing monomers. The acrylic copolymer preferably contains less than 10 wt%, preferably less than 5 wt%, preferably less than 2 wt% of any monomer other than the monomers of Formula (IV) and carboxylic acid-containing monomer as described in i. and ii. above. In a particular embodiment, components i. and ii. make up the entirety of the monomer components of the acrylic copolymer.

In a particular embodiment, the acrylic copolymer does not comprise a hydrolysable monomer, such as a silyl ester monomer. Preferably, the acrylic copolymer is non-hydrolysable.

Preferably, the acrylic copolymer has a weight average molecular weight (Mw) of 10,000 to 50,000 g/mol, preferably 15,000 to 45,000.

The acrylic copolymer may have an acid value of 2 to 60 mg KOH/g polymer as measured according to the acid value test described in the examples section, such as 5 to 40 mg KOH/g polymer.

The binder system of the invention may comprise 1 to 20 wt% (dry solids) of the acrylic copolymer, preferably 2 to 15 wt% (dry solids), more preferably 5 to 10 wt% (dry solids), relative to the total weight of the binder system as a whole.

(Meth)acrylate monomer i.

The (meth)acrylate monomer to be used in the acrylic copolymer is preferably of Formula (IV):

(IV)

9 wherein R is hydrogen or methyl, and R is a C1-C20 hydrocarbyl, preferably a Cl-8 alkyl substituent, most preferably methyl, ethyl, n-propyl, n-butyl or 2-ethylhexyl. Particularly preferred R⁹ groups are methyl, n-butyl, and 2ethylhexyl.

Monomers according to Formula (IV) are referred to as “non-hydrophilic” monomers herein.

In a particular embodiment, the acrylic copolymer comprises at least one (meth)acrylate monomer of Formula (IV) selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate and 225 ethylhexyl methacrylate. In a particular embodiment, the acrylic copolymer comprises at least two different monomers of Formula (IV).

In a particular embodiment, the acrylic copolymer comprises methyl methacrylate as one monomer and at least one other monomer of Formula (IV). In a further particular embodiment, the acrylic copolymer comprises at least methyl methacrylate and n-butyl (meth)acrylate. Where one or more (meth)acrylate monomers of Formula (IV) are present, the weight percentage of the sum of these (meth)acrylate monomers in the acrylic copolymer is preferably at most 99.5 wt%, such as at most 99.2 wt%, such as at most 99.0 wt%, such as at most 98.5 wt%, such as 98.0 wt% based on the total weight of the acrylic copolymer.

Furthermore, where one or more (meth)acrylate monomers of Formula (IV) are present, the weight percentage of the sum of these (meth)acrylate monomers in the acrylic copolymer is preferably at least 80 wt%, such as at least 85 wt%, such as at least 90 wt%, such as at least 92 wt% based on the total weight of the acrylic copolymer.

Where present, methyl methacrylate is preferably present in an amount of 1.0 to 50 wt% of the acrylic copolymer, preferably 1.5 to 30 wt%, more preferably 1.5 to 25 wt%.

Where present, n-butyl acrylate is preferably present in an amount of 50 to 99 wt% of the acrylic copolymer, preferably 55 to 98 wt%, more preferably 65 to 97 wt%, such as 70 to 95 wt%.

Carboxylic acid-containing monomer ii.

The carboxylic acid-containing monomer(s) to be used in the acrylic copolymer help to provide improved compatibility of the acrylic copolymer in the coating film. The carboxylic acid-containing monomer(s) are interchangeably referred to as acidic monomer(s) herein. Above the optimum range of acidic monomer content acrylic copolymers with high viscosities are obtained. High viscosity of the acrylic copolymer means that higher amounts of solvent are needed for preparation and application of the paint. This is unwanted due to strict VOC regulations.

Preferably, the acidic monomer is present in an amount of 0.5-10 wt% based on the weight of the acrylic copolymer. In further particular embodiments, the carboxylic acid-containing monomer is present in an amount of 0.5-8.0 wt%, such as 1.0-7.5 wt%, such as 1.2-7.0 wt%, such as 1.3-6.5 wt%, such as 1.4-6.0 wt%, based on the weight of the acrylic copolymer.

Examples of carboxylic acid containing monomers include acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, 2-carboxymethyl methacrylate, mono-2(methacryloyloxy)ethyl maleate and mono-2-(methacryloyloxy)ethyl succinate. Preferably, the carboxylic acid-containing monomer is acrylic acid or methacrylic acid, more preferably methacrylic acid. A combination of both acrylic acid and methacrylic acid may be used.

In an alternative embodiment, the acrylic copolymer (D) may be a hydrophilic (meth)acrylate based copolymer. The term hydrophilic is used herein to imply the presence of at least 10 wt% of at least one monomer of Formula (V):

O (v) wherein R¹⁰ is H or CH₃, and R¹¹ is a C3-C18 substituent containing at least one oxygen or nitrogen atom, preferably at least one oxygen atom or R¹¹ represents a poly(alkylene glycol) group. As used herein, this structure defines “hydrophilic” (meth)aciylate monomers.

As indicated in the above formula, the term “hydrophilic (meth)acrylate” requires the R¹¹ group in Formula (V) to include at least one oxygen or nitrogen atom, preferably at least one oxygen atom.

Preferably, the R¹¹ group is of formula (CH2CH2O)n-R¹² where R¹² is a ClC10 hydrocarbyl substituent, preferably a C1-C10 alkyl or C6-C10 aryl substituent, and n is an integer in the range of 1 to 5, preferably 1 to 3. Preferably R¹¹ is of formula (CH2CH₂O)_n-R¹² where R¹² is a Cl-C10 alkyl substituent, preferably CH₃or CH₂CH₃, and n is an integer in the range of 1 to 3, preferably 1 or 2. Such a monomer might be 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2-(2-methoxyethoxy)ethyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2butoxyethoxy)ethyl acrylate, 2-(2-(2-methoxyethoxy)ethoxy]ethyl acrylate, 2-(2-(2ethoxyethoxy)ethoxy]ethyl acrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2-(2-methoxyethoxy)ethyl methacrylate, 2-(2-ethoxyethoxy)ethyl methacrylate, 2-(2-butoxyethoxy)ethyl methacrylate, 2-(2(2-m ethoxy ethoxy) ethoxy] ethyl methacrylate, 2-[2-(2-ethoxyethoxy)ethoxy]ethyl methacrylate.

In an embodiment, the acrylic copolymer (D) includes one or more of 2methoxyethyl acrylate (MEA), 2-methoxyethyl methacrylate (MEMA), 2ethoxyethyl methacrylate (EEMA), 2-(2-ethoxyethoxy)ethyl acrylate (EDEGA) or 2-(2-ethoxyethoxy)ethyl methacrylate (EDEGMA).

In another embodiment, the acrylic copolymer (D) contains at least one monomer of Formula (V) above in which the R¹¹ group is a poly(alkylene glycol) group such as a polyethylene glycol) group. Such a group might have a formula (CH2CH2O)m-R¹³ or (CH2CH(CH₃)O)_m-R¹³ where R¹³ is a Cl-CIO hydrocarbyl substituent, preferably a Cl-CIO alkyl or C6-C10 aryl substituent, and m is an integer in the range of 5 to 100, preferably 5 to 20. Such a monomer might be poly(ethylene glycol) methyl ether acrylate, poly(ethylene glycol) ethyl ether acrylate, poly(ethylene glycol) methyl ether methacrylate, poly(ethylene glycol) ethyl ether methacrylate. Preferred such a monomer have a number average molecular weight (Mn) of 300-4000, more preferably 300-1000.

In an embodiment, the acrylic copolymer (D) contains at least one monomer of Formula (V) above in which the R¹¹ group is a saturated cyclic group containing at least one oxygen or nitrogen atom, preferably at least one oxygen atom. More preferably, Rⁿis a group W-R¹⁴ wherein R¹⁴ is a cyclic ether (such as oxolane, oxane, di oxolane, dioxane optionally alkyl substituted) and W is a C1-C4 alkylene. Such a monomer might be furfuryl acrylate, tetrahydrofurfuryl acrylate, (1,3dioxolan-4-yl)methyl acrylate, furfuryl methacrylate, tetrahydrofiirfuryl methacrylate, (2,2-dimethyl-l,3-dioxolan-4-yl)methyl methacrylate. Preferred cyclic ethers should contain at least 4 atoms in the ring. Most preferably in this embodiment, the compound of Formula (V) is tetrahydrofurfuryl acrylate (THFA) and tetrahydrofurfuryl methacrylate (THFMA).

In this embodiment, monomers of Formula (V) preferably form at least 15 wt% of the acrylic copolymer (D).

The monomer of Formula (V) is preferably 2-methoxyethyl acrylate (MEA), 2-methoxyethyl methacrylate (MEMA), 2-ethoxyethyl methacrylate (EEMA), tetrahydrofurfuryl acrylate (THFA), tetrahydrofurfuryl methacrylate (THFMA), 2(2-ethoxyethoxy)ethyl acrylate (EDEGA) or 2-(2-ethoxyethoxy)ethyl methacrylate (EDEGMA).

Preparation of the acrylic copolymer

The acrylic copolymer may be prepared using polymerization reactions known in the art. Acrylic polymers are preferably prepared using addition polymerization or chain growth polymerization. The polymer may, for example, be obtained by polymerizing a monomer mixture in the presence of a polymerization initiator and optionally a chain transfer agent by any of various methods such as solution polymerization, bulk polymerization, emulsion polymerization, dispersion polymerization and suspension polymerization in a conventional way or by controlled polymerization techniques. In preparing a coating composition using this polymer, the polymer is preferably diluted with an organic solvent to give a polymer solution having an appropriate viscosity. From this standpoint, it is desirable to employ solution polymerization.

Examples of suitable initiators for free-radical polymerization include azo compounds such as dimethyl 2,2’-azobis(2-methylpropionate), 2,2'-azobis(2methylbutyronitrile), 2,2'-azobis(isobutyronitrile) and 1,1'azobis(cyanocyclohexane); and peroxides such as tert-amyl peroxypivalate, tertbutyl peroxy pivalate, Zcrt-amyl peroxy-2-ethylhexanoate, Zc/'Z-butyl peroxy-2ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, tert-butyl peroxydiethylacetate, tert-butyl peroxyisobutyrate, tert-butyl peroxybenozate, 1,1di(tert-amyl peroxy)cyclohexane, Zc/7-amyl peroxy 2-ethylhexyl carbonate, tertbutylperoxy isopropyl carbonate, tert-butylperoxy 2-ethylhexyl carbonate, polyether poly-terLbutylperoxy carbonate, di-/e/7-butyl peroxide and dibenzoyl peroxide.

These compounds are used alone or as a mixture of two or more thereof.

Examples of the organic solvent include aromatic hydrocarbons such as xylene, toluene, mesitylene; ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, methyl isoamyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone; esters such as butyl acetate, /e/V-butyl acetate, amyl acetate, isoamyl acetate, propyl propionate, n-butyl propionate, isobutyl isobutyrate, 2-methoxyethyl acetate, l-methoxy-2-propyl acetate; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dibutyl ether, dioxane, tetrahydrofuran, alcohols such as n-butanol, isobutanol, methyl isobutyl carbinol, benzyl alcohol; ether alcohols such as butoxyethanol, 1methoxy-2-propanol, l-propoxy-2-propanol; terpenes such as limonene; aliphatic hydrocarbons such as white spirit. These solvents may be used alone or in combinations of two or more thereof. Preferred combinations are aromatic hydrocarbons and one or more solvent selected from ketones, esters, ethers, alcohols and ether alcohols.

The acrylic copolymer may be a random copolymer, an alternating copolymer, a gradient copolymer or a block copolymer. The acrylic copolymer is preferably a random copolymer.

Other Binder components

In addition to components (A) to (D) described above, an additional binder can be used to adjust the properties of the antifouling coating film. Examples of binders that can be used include:

hydrophilic copolymers, such as poly(A-vinyl pyrrolidone) copolymers and poly(ethylene glycol) copolymers;

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

(meth)aciylic homopolymers and copolymers, such as poly(n-butyl acrylate) and poly(n-butyl acrylate-co-isobutyl vinyl ether);

metal (meth)acrylate copolymers, such as copolymers comprising zinc (meth)acrylate, zinc hydroxide (meth)acrylate, zinc neodecanoate (meth)acrylate or zinc oleate (meth)acrylate;

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

polyoxalates;

polymeric plasticizers from any of the polymer groups specified above. The term polymeric plasticizer refers to polymers having a glass transition temperature (Tg) below 25°C.

Additional examples of other binders that may be present in the antifouling coating composition of the invention include:

esters of rosin and hydrogenated rosin such as methyl esters, glycerol esters, poly(ethylene glycol) esters, pentaerythritol esters, preferred are methyl esters of gum rosin and hydrogenated gum rosin;

dimerized and polymerized rosin;

alkyd resins and modified alkyd resins;

hydrocarbon resin, 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.

If, in addition to components (A) to (D) a further binder is present, the weight ratio of the binder system comprising (A) to (C) and optionally (D):further binder may range from 70:30 to 99:1, preferably from 75:25 to 95:5, especially 80:20 to 90:10.

Biocide

The antifouling coating composition of the invention preferably additionally comprises a compound capable of preventing settlement or growth of marine fouling on a surface. The terms antifouling agent, antifoulant, biocide, active compounds, toxicant are used in the industry to describe known compounds that act to prevent marine fouling on a surface. The antifouling agents of the invention are marine antifouling agents.

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. cuprous oxide and cupric oxide, copper thiocyanate and copper sulfide, copper powder and copper flakes.

Examples of organometallic marine antifouling agents include zinc pyrithione, copper pyrithione, zinc bis(dimethyldithiocarbamate) [ziram] and zinc ethylenebis(dithiocarbamate) [zineb].

Examples of organic marine antifouling agents include heterocyclic compounds such as 2-(ter/-butylamino)-4-(cyclopropylamino)-6-(methylthio)-l,3,5triazine [cybutryne], 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 1,2benzisothiazolin-3-one [DCOIT], 3-(3,4-dichlorophenyl)-1,1-dimethylurea [diuron] 7V-dichlorofluoromethylthio-7V',7V'-dimethyl-7V-phenylsulfamide [dichlofluanid], Ndichlorofluoromethylthio-7V',7V'-dimethyl-7V-/?-tolylsulfamide [tolylfluanid], N(2,4,6-trichlorophenyl)maleimide, triphenylborane pyridine [TPBP], 3-iodo-2propynyl Λ-butylcarbamate [IPBC], 2,4,5,6-tetrachloroisophthalonitrile [chlorothalonil], /?-((diiodomethyl)sulphonyl)toluene, 4-bromo-2-(4-chlorophenyl)5-(trifluoromethyl)-lH-pyrrole-3-carbonitrile [tralopyril] and 4-[l-(2,3-dimethylphenyl)ethyl]-lH-imidazole [medetomidine].

Other examples of marine antifouling agents may be tetraalkylphosphonium halogenides, guanidine derivatives such as dodecylguanidine monohydrochloride; macrocyclic lactones including avermectins and derivatives thereof such as ivermectine; spinosyns and derivatives such as spinosad; capsaicin and derivatives such as phenylcapsaicin; and enzymes such as oxidase, proteolytically, hemicellulolytically, cellulolytically, lipolytically and amylolytically active enzymes.

Copper based antifouling coating compositions contain inorganic copper biocides such as metallic copper, cuprous oxide, copper thiocyanate and the like to prevent hard fouling.

The cuprous oxide material has a typical particle diameter distribution of 0.170 pm and an average particle size (d50) of 1-25 pm. The cuprous oxide material may contain a stabilizing agent to prevent surface oxidation and caking. Examples of commercial available cuprous oxide paint grades include Nordox Cuprous Oxide Red Paint Grade, Nordox XLT from Nordox AS, Cuprous oxide from Furukawa Chemicals Co., Ltd.; Red Copp 97N, Purple Copp, Lolo Tint 97N, Chemet CDC, Chemet LD from American Chemet Corporation; Cuprous Oxide Red from SpiessUrania; Cuprous oxide Roast, Cuprous oxide Electrolytic from Taixing Smelting Plant Co., Ltd.

Antifouling coating compositions without inorganic copper biocides typically use a series of organic biocides such as 4-[l-(2,3-dimethylphenyl)ethyl]IH-imidazole [medetomidine] and 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)lH-pyrrole-3-carbonitrile [tralopyril] to prevent hard fouling. Any known biocide can be used in the invention.

Preferred biocides are cuprous oxide, copper thiocyanate, zinc pyrithione, copper pyrithione, zinc ethylenebis(dithiocarbamate) [zineb], 2-(tert-butylamino)-4(cyclopropylamino)-6-(methylthio)-l,3,5-triazine [cubutryne], 4,5-dichloro-2-noctyl-4-isothiazolin-3-one [DCOIT], N-dichlorofhioromethylthio-N',N'-dimethyl-Nphenylsulfamide [dichlorofluanid], N-dichlorofluoromethylthio-N',N'-dimethyl-N-ptolylsulfamide [tolylfluanid], triphenylborane pyridine [TPBP] and 4-bromo-2-(4chlorophenyl)-5-(trifluoromethyl)-lH-pyrrole-3-carbonitrile [tralopyril], 4-[ 1-(2,3dimethylphenyl)ethyl]-lH-imidazole [medetomidine] and phenylcapsaicin.

A mixture of biocides can be used as is known in the art as different biocides operate against different marine fouling organisms. Mixtures of antifouling agents are generally preferred.

In one embodiment the antifouling coating composition comprises cuprous oxide and/or copper thiocyanate and one or more agents selected from copper pyrithione, zineb, 4,5-dichloro-2-octyl-4-isothiazolin-3-one and medetomidine.

In an alternative embodiment the antifouling coating is free of an inorganic copper biocide. In this embodiment, a preferred biocide combination involves a combination of tralopyril and one or more selected from zinc pyrithione, zineb, 4,5dichloro-2-octyl-4-isothiazolin-3-one and medetomidine.

Where present, the combined amount of biocides may form up to 60 wt% of the coating composition, such as 0.1 to 50 wt%, e.g. 5 to 45 wt%. Where inorganic copper compounds are present, a suitable amount of biocide 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 10 wt%. It will be appreciated that the amount of biocide will vary depending on the end use and the biocide used.

Some biocides 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 biocide present and not therefore to any carrier used.

Other components

In addition to the binder and any of the optional components described above, the antifouling coating composition according to the present invention may optionally further comprise one or more components selected among inorganic or organic pigments, extenders and fillers, additives, solvents and thinners.

The pigments may be inorganic pigments, organic pigments or a mixture thereof. Inorganic pigments are preferred. Examples of inorganic pigments include titanium dioxide, red iron oxide, yellow iron oxide, black iron oxide, zinc oxide, zinc sulfide, lithopone and graphite. Examples of organic pigments include carbon black, phthalocyanine blue, phthalocyanine green, naphthol red and diketopyrrolopyrrole red. Pigments may optionally be surface treated to be more easily dispersed in the paint composition.

Examples of extenders and fillers are minerals such as dolomite, plastorite, calcite, quartz, baryte, magnesite, aragonite, silica, nepheline syenite, wollastonite, talc, chlorite, mica, kaolin, pyrophyllite, perlite, silica and feldspar; synthetic inorganic compounds such as calcium carbonate, magnesium carbonate, barium sulfate, calcium silicate, zinc phosphate and silica (colloidal, precipitated, fumed, etc.); polymeric and inorganic microspheres such as uncoated or coated hollow and solid glass beads, uncoated or coated hollow and solid ceramic beads, porous and compact beads of polymeric materials such as poly(methyl methacrylate), poly(methyl methacrylate-co-ethylene glycol dimethacrylate), poly(styrene-coethylene glycol dimethacrylate), poly(styrene-co-divinylbenzene), polystyrene, poly(vinyl chloride).

Preferably the total amount of extender and/or pigment present in the compositions of the invention is 2-60 wt%, more preferably 5-50 wt% and still more preferably 7-45 wt%, based on the total weight of the composition. The skilled person will appreciate that the extender and pigment content will vary depending on the particle size distribution, the particle shape, the surface morphology, the particle surface-resin affinity, the other components present and the end use of the coating composition.

Examples of additives that can be added to an antifouling coating composition are reinforcing agents, rheology modifiers, wetting and dispersing agents, defoamers and plasticizers.

Examples of reinforcing agents are flakes and fibres. Fibres include natural and synthetic inorganic fibres and natural and synthetic organic fibres e.g. as described in WO 00/77102. Representative examples of fibres include mineral-glass fibres, wollastonite fibres, montmorillonite fibres, tobermorite fibres, atapulgite fibres, calcined bauxite fibres, volcanic rock fibres, bauxite fibres, rockwool fibres, and processed mineral fibres from mineral wool. Preferably, the fibres have an average length of 25 to 2,000 pm and an average thickness of 1 to 50 pm 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 rheology modifiers include thixotropic agents, thickening agents and anti-settling agents. Representative examples of rheology modifiers are 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. Rheology modifiers that need activation may be added to the coating composition as is and activated during the paint production process or they can be added to the coating composition in a pre-activated form, e.g. solvent paste. Preferably rheology modifiers are each present in the composition of the invention in an amount of 0-5.0 wt%, more preferably 0.2-3.0 wt% and still more preferably 0.5-2.0 wt%, based on the total weight of the coating composition.

Examples of plasticizers are polymeric plasticizers, silicone oils (nonreactive polydimethylsiloxanes), chlorinated paraffins, phthalates, phosphate esters, sulphonamides, adipates, epoxidised vegetable oils and sucrose acetate isobutyrate. Preferably plasticizers are present in the compositions of the invention in an amount of 0-10 wt%, more preferably 0.5-7 wt% and still more preferably 1-5 wt%, based on the total weight of the coating composition.

Dehydrating agents and stabilizers improve the storage stability of the antifouling coating compositions. The dehydrating agent is preferably a compound which removes moisture and water from the coating composition. It is also referred to as water scavenger or drying agent. The dehydrating agents may be hygroscopic materials that absorb water or bind water as crystal water. These are often referred to as desiccants. Examples of such compounds include anhydrous calcium sulphate, calcium sulphate hemihydrate, anhydrous magnesium sulphate, anhydrous sodium sulphate, anhydrous zinc sulphate, molecular sieves and zeolites. The dehydrating agents may also be compounds that chemically react with water. Examples of dehydrating agents that react 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-te/7-butyl borate; organosilanes such as trimethoxymethylsilane, triethoxymethylsilane, tetraethoxysilane, phenyltrimetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and ethyl polysilicate.

The preferred dehydrating agents are organosilanes, such as tetraethoxysilane, and inorganic desiccants. The use of a organosilane is especially preferred.

Stabilizers are preferably acid scavengers. Examples of stabilizers are carbodiimide compounds, such as bis(2,6-diisopropylphenyl)carbodiimide, bis(2methylphenyl)carbodiimide and l,3-di-/?-tolylcarbodiimide.

Preferably the dehydrating agents and stabilizers are each 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.

In one particularly preferred embodiment of the invention, the coating composition comprises a dehydrating agent and/or a stabiliser, especially a dehydrating agent.

It is highly preferred if the antifouling composition contains a solvent. This solvent is preferably volatile and is preferably organic. Examples of organic solvents and thinners are aromatic hydrocarbons such as xylene, toluene, mesitylene; ketones such as methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, methyl amyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone; esters such as butyl acetate, tert-butyl acetate, amyl acetate, isoamyl acetate, propyl propionate, n-butyl propionate, isobutyl isobutyrate; ether esters such as 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, ethyl 3-ethoxypropionate; ethers such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dibutyl ether, dioxane, tetrahydrofuran; alcohols such as //-butanol, isobutanol, methyl isobutyl carbinol, benzyl alcohol; ether alcohols such as butoxyethanol, l-methoxy-2-propanol, l-propoxy-2-propanol; terpenes such as limonene; aliphatic hydrocarbons such as white spirit; and optionally a mixture of two or more solvents and thinners.

Preferred solvents are ketones and aromatic solvents, especially xylene and mixtures of aromatic hydrocarbons and/or ketones.

The amount of solvent is preferably as low as possible. The solvent content may be up to 40 wt% of the composition, preferably up to 35 wt% of the composition, such as up to 30 wt% but may be as low as 15 wt% or less, e.g. 10 wt% or less. Again, the skilled person will appreciate that some raw materials comprise solvent and contribute to the total solvent content as specified above and that the solvent content will vary depending on the other components present and the end use of the coating composition.

Alternatively, the coating can be dispersed in an organic non-solvent for the film-forming components in the coating composition or in an aqueous dispersion.

The antifouling coating composition of the invention should preferably have solids content above 45 vol%, e.g. above 50 vol%, such as above 52 vol%, preferably above 55 vol%.

More preferably the antifouling coating composition should have a content of volatile organic compounds (VOC) below 500 g/L, preferably below 420 g/L, more preferably below 400 g/L, e.g. below 380 g/L. VOC content can be calculated as described in e.g. ASTM D5201-01 or IED 2010/75/EU or measured, e.g. as described in US EPA Method 24 or ISO 11890-2.

The viscosity of the coating composition may be in the range of less than 1000 cP, such as less than 800 cP, e.g. less than 500 cP when measured using a Cone and Plate viscometer in accordance with ISO 2884.

The antifouling coating composition of the invention can be applied to a whole or part of any object 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 object 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 can be accomplished by any convenient means, e.g. via painting (e.g. with brush or roller) or spraying the coating onto the object. 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.

When applying the antifouling coating to an object (e.g. a ship hull) the surface of the object is not protected solely by a single coat of antifouling coating composition. Depending on the nature of the surface, the antifouling coating can be applied directly to an existing coating system. Such a coating system may comprise several layers of paint of different generic types (e.g. epoxy, polyester, vinyl or acrylic or mixtures thereof). Starting with an uncoated surface (e.g. steel, aluminium, plastic, composite, glass fiber or carbon fiber) the full coating system will typically comprise one or two layers of an anticorrosive coating (e.g. curable epoxy coating or curable modified epoxy coating), one layer of tie-coat (e.g. curable modified epoxy coating or physical drying vinyl coating) and one or two layers of antifouling paint. In exceptional cases further layers of antifouling paint may be applied. If the surface is a clean and intact antifouling coating from a previous application, the new antifouling paint can be applied directly, typically as one or two coats with more in exceptional cases. When two or more coats of antifouling coating composition is applied, the different coats can be antifouling coatings of different compositions. Examples of antifouling coating systems combining different antifouling coating compositions may be a coating system with antifouling coating compositions of the invention where the antifouling coating in the first coat has a binder composition with a higher content of the silyl ester copolymer (A) than the antifouling coating in the final coat; a coating system with antifouling coating compositions of the invention where the antifouling coating in the first coat has a binder composition with a higher content of the silyl ester copolymer (B) than the antifouling coating in the final coat; a coating system with an antifouling coating system outside the invention in the first coat and an antifouling coating composition of the invention in the final coat.

The invention will now be defined with reference to the following nonlimiting examples.

Examples

Materials and methods

Testing

Determination of polymer solution viscosity

The viscosity of the polymers was determined in accordance with ASTM D2196 Test Method A using a Brookfield DV-I Prime digital viscometer with LV-2 or LV4 spindle at 12 rpm. The polymer solutions were tempered to 23.0 °C ± 0.5 °C before the measurements.

Determination of non-volatile matter content of the polymer solutions

The non-volatile matter content in the polymer solutions was determined in accordance with ISO 3251. A test sample of 0.5 g ± 0.1 g was taken out and dried in a ventilated oven at 105 °C for 3 hours. The weight of the residual material was considered to be the non-volatile matter (NVM). The non-volatile matter content is expressed in weight percent. The value given is the average of three parallel measurements.

Determination of polymer molecular weights distribution

The polymers were characterised by Gel Permeation Chromatography (GPC) measurement. The molecular weight distribution (MWD) was determined using a Malvern Omni sec Resolve and Reveal system with two PLgel 5 pm Mixed-D columns from Agilent in series, tetrahydrofuran (THF) as eluent at a constant flow rate of 1 ml/min and with a refractive index (RI) detector. The columns were calibrated using narrow polystyrene standards Polystyrene Medium EasiVials (4 ml) Red, Yellow and Green from Agilent. The column oven temperature and the detector oven temperature were 35 °C. The sample injection volume was 100 pl.

The data were processed using Omnisec 5.1 software from Malvern.

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 minimum 3 hours at room temperature prior to sampling for the GPC measurements. Before analysis the samples were filtered through 0.45 pm Nylon filters. The weight-average molecular weight (Mw) and the poly dispersity index (PDI), given as Mw/Mn, are reported in the tables.

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 Instruments DSC Q200. The sample was prepared by drawdown of the polymer solution on a glass panel using an applicator with 100 pm gap size. The glass panel was dried over night at room temperature and subsequently 24 hours at 50 °C in a ventilated heating cabinet. The dry polymer material was scraped off the glass panels and approx. 10 mg of the dry polymer material was transferred to an aluminium pan. The pan was sealed with a non-hermetic lid. The measurement was performed by running a heat-cool-heat procedure, within a temperature range from 80 °C to 120 °C, with a heating rate of 10 °C/min and cooling rate of 10 °C/min and using an empty pan as reference. 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.

Determination of acid value by colorimetric titration

The acid value of the polymers was determined according to the procedure described in ISO 2114:2000 Method A. A weighed quantity of the polymer solution was dissolved in lotun Thinner No. 17. Phenolphthalein was added as colour indicator and the solution was titrated with 0.1 M KOH solution in ethanol until a red colouration appeared and was stable for 10-15 s while the solution was stirred. The acid value for the dry polymers were calculated based on measured non-volatile matter of the tested polymer solution. The reported acid value is the average value of three parallel measurements.

General procedure for preparation of copolymer solutions S1-S10 and CS1-CS9 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 and initiator was prepared. The pre-mix was charged to the reaction vessel at a constant rate over 2 hours under a nitrogen atmosphere. After further 30 minutes reaction, post-addition of a boost initiator solution was added. The reaction vessel was maintained at the reaction temperature for a further 2 hours. The reactor was then heated to 105 °C and kept at this temperature for 1 hour. Finally, the reactor was cooled to room temperature. In the preparation of SI, a quantity of solvent was added for thinning during the cooling process.

The ingredients for preparing the copolymers are listed in Tables 1 and 2 below. All amounts are given in parts by weight.

Table 1. Silyl copolymer ingredients and properties (amounts given in parts by weight).

Comparative	CS3	0Ό9	35.0	20.0	1	20.0	5.0	20.0	(N i—H	0.2	O	1	60.4	1097	33.8	3.4	CT)
CS2	0Ό9	30.0	25.0	0Ό1		5.0	30.0	(N i—H	0.2	O		60.5	o i—H i—H	32.6	CC	IT)
CS1	0Ό9	45.0	0Ό1	0Ό1		5.0	30.0	(N i—H	0.2	O		9Ό9	1627	29.8	i—H cc	cn
Copolymer solutions	C/j	0Ό9		55.0		15.0	5.0	25.0	(N i—H	0.2	O		60.2	622	00 (N	3.4	CT) (N
S4	0Ό9	1	55.0	0Ό1	1	5.0	30.0	(N i—H	0.2	O	1	58.6	372	26.9	CC	i—H i—H
S3	009	1	55.0	5.0	1	5.0	35.0	(N i—H	0.2	O	1	60.5		29.2	CC	i—H CT)
rq c»	009	55.0		1	20.0	5.0	20.0	(N i—H	0.2	o		60.2	o i—H i—H	00 (N	2.9	σ>
55	0Ό9	55.0	1	10.0	1	5.0	30.0	(N i—H	0.2	ι/Ί		tn	997	27.2	2.8
	Polymer	Xylene	Triisopropylsilyl methacrylate	Triisopropylsilyl acrylate	2-(2 -Ethoxy ethoxy)ethyl acrylate	Tetrahydrofurfuryl acrylate	n-Butyl acrylate	Methyl methacrylate	2,2’-Azobis(2- methylbutyronitrile)	2,2’-Azobis(2- methylbutyronitrile)	Xylene	Xylene	Non volatile matter (wt%)	Viscosity (cP)	Mw (kD)	PDI	Tg (°C)
		Reactor charge	Feed charge	Boost charge	Thinning	Copolymer solution properties

Table 2. Silyl copolymer ingredients and properties (amounts given in parts by weight).

Comparative

CS9

Ο ο SO

Ο

13.0

8.0

21.0

04

0.2

SO

60.7

1380

34.6

o

CS8

ο ο SO

ο

Ο

Ο ο 04

Ο wS

Ο ο 04

04

04 Ο

SO

o SO

1302

36.9

IT)

00 CO

CS7

ο ο SO

ο

Ο 00

Ο ο 04

ο wS

Ο ο 04

04

Ο

SO

o SO

1315

IT)

Os CO

CS6

Ο Ο SO

35.0

ο ο 04

ο ο

ο wS

Ο ο

04

Γ4 Ο

SO

60.2

1527

36.0

IT)

CO

CS5

Ο Ο SO

Ο ο

Ο wS

ο ο

ο wS

ο ο

ο

sq

o SO

1565

xj^-

σ> CO

CS4

Ο Ο SO

50.0

Ο wS

ο ο

ο wS

ο ο

04

Ο

so

o o SO

o

CO

Μ

Copolymer solutions

o (Z2

Ο Ο SO

>

50.0

>

ο wS

>

ο wS

ο ο

Ο

IT)

wS

wS IT)

C4 O

Γ—

o 04

OS CO

Ο Ο SO

Ο ο

Ο wS

25.0

04

Ο

SO

00 o SO

IT) IT) IT)

26.0

IT)

SO co

00 ζΛ

Ο Ο SO

>

55.0

>

ο ο 04

>

ο Ό)

Ο ο 04

04

Ο

SO

>

60.4

IT)

30.2

IT)

SO

Μ

Ο SO

ο '/Ο

ο

Ο

οο ο

ΓΊ Ο

wS

OX >/Ί

Cu

ι/Ί

C-l

03 co

so ζΛ

Ο Ο SO

55.0

Ο wS

ο ο

Ο ο 04

04

Γ4 Ο

SO

60.7

SO

r-’

CO

Polymer

Xylene

Triisopropylsilyl methacrylate

Triisopropylsilyl acrylate

2-(2-Ethoxyethoxy)ethyl acrylate

Tetrahydrofurfuryl acrylate

2-Methoxyethyl acrylate

2-Methoxyethyl methacrylate

n-Butyl acrylate

Methyl methacrylate

2,2 ’-Azobis(2-methylbutyronitrile)

Xylene

Non volatile matter (wt%)

Viscosity (cP)

Mw (kD)

M Q Ph

Tg (°C)

Reactor charge

Feed charge

Boost charge

Thinning

Copolymer solution properties

P1807

General procedure for preparation of co-binder solution Al

55.0 parts of xylene and 7.5 parts of l-methoxy-2-propanol 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 80.0 parts 2-ethylhexyl acrylate, 17.0 parts methyl methacrylate, 3.0 parts methacrylic acid and 1.2 parts 2,2’-azobis(2methylbutyronitrile) was prepared. The pre-mix was charged to the reaction vessel at a constant rate over 2.5 hours under a nitrogen atmosphere. After further 30 minutes reaction, post-addition of a boost initiator solution of 0.2 parts 2,2’-azobis(2methylbutyronitrile) and 5.1 parts xylene was added. The reaction vessel was maintained at the reaction temperature for a further 2 hours. Finally, the reactor was cooled to room temperature. The amounts of ingredients are given in parts by weight.

The copolymer solution had the following properties:

Non volatile matter 59.4 wt%; Viscosity 640 cP; Mw 39.2 kD; Tg -41 °C;

Acid value 19 mg KOH/g (dry polymer).

General procedure for preparation of antifouling coating compositions

The components were mixed in the proportions given in Tables 4 and 5. (Trade names and manufacturer of selected ingredients in the antifouling coating compositions are displayed in Table 3.) The mixture was dispersed in the presence of glass beads (approx. 2 mm in diameter) in a paint can of 250 ml using a vibrational shaker for 15 minutes. The glass beads were filtered out before testing.

Determination of paint viscosity using Cone and Plate viscometer

The viscosity of the antifouling paint composition was determined in accordance with ISO 2884-1:1999 using a digital Cone and Plate viscometer set at a temperature of 23 °C, working at a shear rate of 10 000 s'¹ and providing viscosity measurement range of 0-10 P. The result is given as the average of three measurements.

Calculation of the volatile organic compound (VOC) content of the antifouling coating composition

The volatile organic compound (VOC) content of the antifouling coating composition was calculated in accordance with ASTM D5201.

Accelerated cracking testing of coating films

PVC panels (20 cm x 40 cm) that had been degreased with solvent and sanded for improved adhesion of the coating were used for the test. The panels were coated with Safeguard Plus (two-component polyamide cured vinyl epoxy based coating, manufactured by Chokwang Jotun Ltd., Korea) using airless spray. The applied film thickness were within the recommended intervals in the technical data sheet for the product.

After a minimum drying time of 24 hours at room temperature the antifouling coating compositions were applied on the pre-coated panels using a film applicator with gap size of 800 pm. The test area of the coating films were approx. 5 cm x 9 cm. The panels were dried for 72 h at 52 °C in a ventilated heating cabinet before testing.

The panels were immersed in containers with natural, filtered seawater of 40 °C ± 2 °C flowing through. Every second month the panels were taken out and evaluated for film defects. The panels were dried at RT for 24 h and then at 52 °C for 24h before they were evaluated for cracking visually and under 10 x magnifications. After evaluation the panels were re-immersed.

The evaluation of the cracking is based on the assessment described in ISO 4628 Part 4 (2003). The panels were rated as follows:

Density of cracking:	Size of cracks:
0 - No cracks	SO - Not visible under xlO magnification
1 - Very few cracks 2 - Few cracks	51 - Only visible under xlO magnification 52 - Just visible with normal vision
3 - Moderate number of cracks	S3 - Clearly visible with norma vision
4 - Considerable number of cracks	S4 - Large cracks up to 1 mm wide
5 - Dense cracking	S5 - Very large cracks more than 1 mm wide

The rating after 11 months of exposure are reported in Table 4 and Table 5.

Determination of the polishing of antifouling coating films on rotating disc in seawater

The polishing was determined by measuring the reduction in film thickness of a coating film over time. PVC discs that had been degreased with solvent and sanded were used for the test. The antifouling coating compositions were applied as radial stripes on the disc using a film applicator with a gap size of 300 pm. The thickness of the dry coating films were measured by a surface profiler. The PVC discs were mounted on a shaft and rotated in a container in which seawater is flowing through. The speed of the rotated shaft gave an average simulated speed of 16 knots on the disc. Natural seawater which had been filtered and temperature-adjusted to 30 °C ± 2 °C was used. The PVC discs were taken out every 6 week for measuring the film thickness. The discs were rinsed and allowed to dry overnight at room temperature before measuring the film thickness.

The polishing reported in Table 4 and Table 5 is the reduction in film thickness after 52 weeks of testing.

Testing of antifouling performance in Florida, USA

PVC panels (20 cm x 30 cm) that had been degreased with solvent and sanded for improved adhesion of the coating were used for the test. The panels were coated with a first coat of a commercial primer/tiecoat (Safeguard Plus, two-component polyamide cured vinyl epoxy based coating, manufactured by Chokwang Jotun Ltd., Korea) using airless spray. After a minimum drying time of 24 hours at room temperature a second coat of a commercial antifouling paint (SeaQuantum Ultra S, one component silyl acrylate antifouling coating, manufactured by Jotun Paints (Europe) Ltd., England). The curing/drying time and film thicknesses of the first coat and the second coat were within the recommended intervals in the technical data sheets for the products.

After a minimum drying time of 24 hours at room temperature the antifouling coating compositions of the invention were applied directly to the pre-coated PVC panels as a last coat using a film applicator with a 300 pm gap size. The test area of the coating films were approx. 5 cm x 20 cm. The edges of the panels were sealed with a commercial antifouling product.

The panels were exposed on a raft in Florida where the panels were submerged 0.5 1.5 m below the sea surface. The panels were evaluated by visual inspection and rated according to the scale below. The score is given for the total fouling of algae and animals.

Score / rating of fouling:

0 Excellent	0-10 % of area fouled
1 Very good	11-20% of area fouled
2 Good	21-30% of area fouled
3 Fair	31-40 % of area fouled
4 Poor	41-50% of area fouled
5 Very poor	51-100 % of area fouled

The antifouling performance reported in Table 4 and Table 5 is the fouling score after 10 months of exposure in Florida.

Table 3. Trade name and manufacturer of selected ingredients in the antifouling coating compositions

Ingredient	Trade name	Manufacturer	Properties
Cuprous oxide	Cuprous oxide, paint grade	Nordox AS
Copper pyrithione	Copper Omadine	Lonza
Zinc pyrithione	Zinc Omadine	Lonza
Tralopyril	Econea	Janssen PMP
DCOIT encapsulated (80 wt% active)	Sea-Nine Ultra	Dow Chemical Company	Particle size d50 8-10 pm
Medetomidine	Selektope	1-Tech AB
Gum rosin	Gum rosin, WW grade (origin Portugal)	AV Pound & Co.
Isostearic acid	Radiacid 0907	Oleon NV	Liquid; CAS No. 30399-84-9
Feldspar	Coattun S.PR.C-5	Kaltun Mining Company
Plastorit	Plastorit 0000	Imerys Talc
Iron oxide red	Bayferrox Red 130 M	Lanxess AG
Organic DPP red	Irgazin Red L 3670 HD	BASF SE	Colour red 254; Diketo-pyrrolopyrrole pigment
Polyamide wax (20 wt% in xylene)	Disparlon A603-20X	Kusumoto Chemicals, Ltd.
Oxidised polyethylene wax (25 wt% in xylene)	Disparlon 4401-25X	Kusumoto Chemicals, Ltd.
1-Methoxylpropanol (PM)	Dowanol PM	Dow Chemical

Table 4. Paint formulation compositions (amounts given in parts by weight).

		Paint examples
		P-1	P-2	P-3	P-4	P-5
TIP SMA copolymer solution (A)	SI	19.5	13.0	19.5	13.0	-
S2	-	-	-	-	14.7
TIPSA copolymer solution (B)	S3	4.1	10.3	-	-	-
S4	-	-	4.3	10.6	-
S5	-	-	-	-	8.3
Monocarboxylic acid (C)	Gum rosin solution (60 wt% in xylene)	8.0	8.0	8.0	8.0	8.0
Biocides	Cuprous oxide	35.0	35.0	35.0	35.0	35.0
Copper pyrithione	3.0	3.0	3.0	3.0	3.0
Pigments and extenders	Iron oxide red	2.0	2.0	2.0	2.0	2.0
Titanium dioxide	1.0	1.0	1.0	1.0	1.0
Talc	5.0	5.0	5.0	5.0	5.0
Zinc phosphate	8.0	8.0	8.0	8.0	8.0
Zinc oxide	5.0	5.0	5.0	5.0	5.0
Additives	Polyamide wax (20 wt% in xylene)	1.0	1.0	1.0	1.0	1.0
Oxidised polyethylene wax (25 wt% in xylene)	0.5	0.5	0.5	0.5	0.5
Tetraethoxysilane	0.5	0.5	0.5	0.5	0.5
Solvent	Xylene	7.4	7.7	7.2	7.4	8.1
SUM		100	100	100	100	100

Binder composition (wt% of dry polymer)	Copolymer (A)	61	41	61	41	47
Copolymer (B)	13	33	13	33	27
Monocarboxylic acid (C)	26	26	26	26	26
Binder properties	Tg (°C) copolymer blend (A) + (B)	42	38	38	30	35
Paint properties	Cone & Plate viscosity (cP)	464	429	426	380	470
Calculated VOC (g/L)	390	390	390	390	390
Coating properties	Polishing - 12 mth (pm)	14	32	15	22	30
Cracking - 11 mth	0	0	0	0	0
Antifouling performance (Florida) - 10 mth	0	0	0	1	1

Table 5: Comparative paint formulation compositions (amounts given in parts by weight).

	CP-8	1	1	1	1	22.8	1	1	1	8.0	35.0	3.0	2.0	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
CP-7	1	23.1	1	1	1	1	1	1	8.0	35.0	3.0	2.0	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
CP-6	1	1	1	1	1	1	1	22.7	8.0	35.0	3.0	2.0	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
Comparative exampl	CP-5	1	1	1	23.2	1	1	1	1	8.0	35.0	3.0	2.0	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
CP-4	1	1	22.5	1	1	1	1	1	8.0	35.0	3.0	2.0	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
CP-3	23.9	1	1	1	1	1	1	1	8.0	35.0	3.0	2.0	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
CP-2	1	1	1	1	1	1	22.9	1	8.0	35.0	3.0	o (N	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
CP-1	1	1	1	1	1	23.1	1	1	8.0	35.0	3.0	O (N	o i—H	5.0	8.0	5.0	o i—H	0.5	0.5
		i—H GC	S2	S3	CZ)	S5	CS1	CS2	CS3	Gum rosin solution (60 wt% in xylene)	Cuprous oxide	Copper pyrithione	Iron oxide red	Titanium dioxide	Talc	Zinc phosphate	Zinc oxide	Polyamide wax (20 wt% in xylene)	Oxidised polyethylene wax (25 wt% in xylene)	T etraethoxy sil ane
		TIP SMA copolymer solution (A)	TIP SA copolymer solution (B)	Comparative silyl copolymer solution	Monocarboxylic acid (C)	Biocides	Pigments and extenders	Additives

ο

IT)

8.2	ΟΌΟΐ		1	74	1	26	o	390	71	5(S3)	i—H
IT) i—H	o	i—H
σ>	ΟΌΟΐ		74	1	1	26	519	390
35	o	o
8.3	ΟΌΟΐ				74	26	567	390
65	5(S3)	i—H
00	ΟΌΟΐ			74		26	300	390
47	5(S3)	o
8.5	ΟΌΟΐ		1	74	1	26	385	390
7.1	ΟΌΟΐ		74	1	1	26	477	390	σ>	o	i—H
ι—Η 00	ΟΌΟΐ		1	1	74	26	471	390
26	i—H on i—H	o
IT) i—H	o	o
σ>	ΟΌΟΐ		1	1	74	26	00	390
Xylene			Copolymer (A)	Copolymer (B)	Comparative copolymer	Monocarboxylic acid (C)	Cone & Plate viscosity (cP)	Calculated VOC (g/L)	Polishing - 12 mth (pm)	Cracking - 11 mth	Antifouling performance (Florida) - 10 mth
Solvent	SUM		Binder composition (wt% of dry polymer)	Paint properties	Coating properties

ο ο. ε

Paint examples

PA-8

O r--H

8.3

9.0

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o

00

0 001

PA-7

(N i—H

00 id

9.0

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o

8.6

0 001

PA-6

σ> i—H

9.0

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o

8.6

0 001

PA-5

13.0

o i—H

9.0

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o

σ>

0 001

PA-4

15.2

8.5

9.0

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o

00

0 001

PA-3

17.4

o'

0 6

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o'

00

100.0

PA-2

19.5

9.0

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o

00

0001

PA-1

21.8

i—H (N

9.0

•D i—H

28.0

o

3.0

o i—H

15.5

•D

(N

o

7.7

0001

SI (57.7 wt% in xylene)

S2 (60.2 wt% in xylene)

S4 (58.6 wt% in xylene)

S8 (60.4 wt% in xylene)

Gum rosin solution (60 wt% in xylene)

Isostearic acid

Cuprous oxide

Copper pyrithione

Iron oxide red

Titanium dioxide

Plastorit

Zinc oxide

Polyamide wax (20 wt% in xylene)

T etraethoxy sil ane

Xylene

TIPSMA copolymer solution (A)

TIP SA copolymer solution (B)

Monocarboxylic acid (C)

Biocides

Pigments and extenders

Additives

Solvent

SUM

(Μ

Paint examples	PA-8	64:36	33	394	375
PA-7	75:25	33	o o	375
PA-6	85:15	33	429	375
PA-5	55:45	33	351	375
PA-4	64:36	33	362	375
PA-3	73:27	33	383	375
PA-2	82:18	33	00 00	IQ
PA-1	91:9	33	411	375
		Weight ratio (A):(B)	Monocarboxylic acid (C) (wt%)	Cone & Plate viscosity (cP)	Calculated VOC (g/L)
		Binder system (dry polymer)	Paint properties

CTi

IT)

Comparative examples	CPA-8	1	1	22.7	1	1	1	1	1	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
CPA-7	1	1	1	1	1	1	1	22.9	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
CPA-6	1	1	1	1	1	1	22.9	1	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
CPA-5	1	22.8	1	1	1	1	1	1	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
CPA-4	1	1	1	1	1	22.9	1	1	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
CPA-3	1	1	1	1	23.0	1	1	1	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
CPA-2	22.8	1	1	1	1	1	1	1	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
CPA-1	1	1	1	23.0	1	1	1	1	9.0	ι/Ί i—H	28.0	o	3.0	o i—H	15.5
		CS1 (60.6 wt% in xylene)	CS2 (60.5 wt% in xylene)	CS3 (60.4 wt% in xylene)	CS4 (60.0 wt% in xylene)	CS5 (60.1 wt% in xylene)	CS6 (60.2 wt% in xylene)	CS7 (60.7 wt% in xylene)	CS8 (60.3 wt% in xylene)	Gum rosin solution (60 wt% in xylene)	Isostearic acid	Cuprous oxide	Copper pyrithione	Iron oxide red	Titanium dioxide	Plastorit
		Comparative copolymer	Monocarboxylic acid (C)	Biocides	Pigments and extenders

Comparative examples

CPA-8

•D

(N i—H

o'

8.9

0'001

1

33

PA-8

375

CPA-7

•D

(N i—H

o'

00

0'001

1

33

PA-7

460

375

CPA-6

•D

(N i—H

o

oo

0'001

1

33

PA-6

460

375

CPA-5

•D

(N i—H

o'

8.8

0'001

1

33

PA-5

405

375

CPA-4

•D

(N i—H

o'

00

0'001

1

33

PA-4

403

375

CPA-3

•D

(N i—H

o'

8.6

0'001

1

33

PA-3

411

375

CPA-2

•D

(N i—H

o'

8.8

0'001

1

33

PA-2

CN

375

CPA-1

•D

(N i—H

o'

8.6

0'001

1

33

PA-1

432

375

Zinc oxide

Polyamide wax (20 wt% in xylene)

T etraethoxy sil ane

Xylene

Weight ratio (A):(B)

Monocarboxylic acid (C) (wt%)

Comparative blend

Cone & Plate viscosity (cP)

Calculated VOC (g/L)

Additives

Solvent

SUM

Binder system (dry polymer)

Paint properties

Table 8. Paint formulation compositions (amounts given in parts by weight).

		Paint examples
		PB-1	PB-2	PB-3	PB-4
TIPSMA copolymer solution (A)	SI (57.7 wt% in xylene)	20.5	16.1	-	-
S6 (60.7 wt% in xylene)	-	-	22.1	-
S7 (54.9 wt% in xylene)	-	-	-	13.2
TIPSA copolymer solution (B)	S4 (58.6 wt% in xylene)	4.4	8.7	-	-
S9 (60.8 wt% in xylene)	-	-	5.5	-
S10 (55.3 wt% in xylene)	-	-	-	9.8
Monocarboxylic acid (C)	Gum rosin solution (60 wt% in xylene)	8.0	8.0	10.9	6.0
Co-binders	Al (59.4 wt% in solvent)	-	-	3.5	-
Biocides	Cuprous oxide	35.0	35.0	-	50.0
Copper pyrithione	-	-	-	1.5
Zinc pyrithione	-	-	3.5	-
Tralopyril	-	-	4.0	-
Encapsulated DCOIT (80 wt% active)	2.5	2.5	-	-
Pigments and extenders	Iron oxide red	2.0	2.0	4.5	-
Organic DPP red	-	-	-	0.5
Titanium dioxide	1.0	1.0	-	2.0
Feldspar	-	-	14.0	-
Talc	5.0	5.0	9.0	3.5
Zinc phosphate	8.0	8.0	-	-
Zinc oxide	5.0	5.0	11.0	4.5
Additives	Polyamide wax (20 wt% in xylene)	1.0	1.0	1.0	0.9
Oxidised polyethylene wax (25 wt% in xylene)	0.5	0.5	-	0.6
Tetraethoxysilane	0.5	0.5	1.0	0.2
Solvent	Xylene	6.6	6.7	10.0	7.3
SUM		100.0	100.0	100.0	100.0

Binder system (dry polymer)	Weight ratio (A):(B)	82:18	64:36	80:20	57:43
Monocarboxylic acid (C) (wt%)	25	25	26	22

		Paint examples
		PB-1	PB-2	PB-3	PB-4
Paint properties	Cone & Plate viscosity (cP)	613	555	405	609
Calculated VOC (g/L)	381	381	387	408

Table 9. Comparative paint formulation compositions (amounts given in parts by weight).

		Comparative examples
		CPB-1	CPB-2	CPB-3
Comparative copolymer	CS1 (60.6 wt% in xylene)	24.0	-	-
CS6 (60.2 wt% in xylene)	-	23.8	-
CS9 (60.7 wt% in xylene)	-	-	27.6
Monocarboxylic acid (C)	Gum rosin solution (60 wt% in xylene)	8.0	8.0	10.9
Co-binders	Al (59.4 wt% in solvent)	-	-	3.5
Biocides	Cuprous oxide	35.0	35.0	-
Zinc pyrithione	-	-	3.5
Tralopyril	-	-	4.0
Encapsulated DCOIT (80 wt% active)	2.5	2.5	-
Pigments and extenders	Iron oxide red	2.0	2.0	4.5
Titanium dioxide	1.0	1.0	-
Feldspar	-	-	14.0
Talc	5.0	5.0	9.0
Zinc phosphate	8.0	8.0	-
Zinc oxide	5.0	5.0	11.0
Additives	Polyamide wax (20 wt% in xylene)	1.0	1.0	1.0
Oxidised polyethylene wax (25 wt% in xylene)	0.5	0.5	-
Tetraethoxysilane	0.5	0.5	1.0
Solvent	Xylene	7.5	7.7	10.0
SUM		100.0	100.0	100.0

Binder system (dry polymer)	Weight ratio (A):(B)	-	-	-

		Comparative examples
		CPB-1	CPB-2	CPB-3
	Monocarboxylic acid (C) (wt%)	25	25	26
Comparative blend	PB-1	PB-2	PB-3
Paint properties	Cone & Plate viscosity (cP)	625	603	429
Calculated VOC (g/L)	381	381	387

Table 10: 2K paint formulation compositions (amounts given in parts by weight).

			Paint ex.	Comp. ex.
			PC-1	CPC-1
Comp. A	TIPSMA copolymer solution (A)	S2 (60.2 wt% in xylene)	17.0	-
TIPSA copolymer solution (B)	S8 (60.4 wt% in xylene)	5.7	-
Comparative copolymer	CS8 (60.3 wt% in xylene)	-	22.6
Biocides	Cuprous oxide	34.9	34.9
Copper pyrithione	3.0	3.0
Pigments and extenders	Iron oxide red	2.0	2.0
Talc	3.0	3.0
Zinc phosphate	4.0	4.0
Additives	Polyamide wax (20 wt% in xylene)	0.8	0.8
Oxidised polyethylene wax (25 wt% in xylene)	0.5	0.5
T etraethoxysilane	0.5	0.5
Solvent	Xylene	7.0	7.1
SUM		78.4	78.4
Comp. B	Monocarboxylic acid (C)	Gum rosin solution (60 wt% in xylene)	7.9	7.9
Biocides	Medetomidine (20 wt% solution in PM)	1.0	1.0
Pigments and extenders	Titanium dioxide	1.0	1.0
Talc	2.0	2.0
Zinc phosphate	4.0	4.0
Zinc oxide	5.0	5.0
Additives	Polyamide wax (20 wt% in xylene)	0.2	0.2

			Paint ex.	Comp. ex.
			PC-1	CPC-1
	Solvent	Xylene	0.5	0.5
SUM		21.6	21.6

Mixed paint	Binder system (dry polymer)	Weight ratio (A):(B)	75:25	-
Monocarboxylic acid (C) (wt%)	26	26
Paint properties	Cone & Plate viscosity (cP)	469	497
Calculated VOC (g/L)	389	389

Comparative copolymer CS1 in Coating composition CPI has a monomer composition similar to the blends of SI + S3 and SI + S4 as in coating composition 5 Pl andP3.

Comparative copolymer CS2 in Coating composition CP2 has a monomer composition similar to the blends of SI + S3 and SI + S4 as in coating composition P2 and P4.

Comparative copolymer CS3 in Coating composition CP6 has a monomer composition similar to the blends of S2 + S5 as in coating composition P5.

The results for paint viscosity in Tables 2 and 3 show that it is advantageous to use blends of TIPSMA copolymer (A) and TIPSA copolymer (B) compared to a TIPSMA-TIPSA copolymer to achieve reduced viscosity.

Claims

Claims

1. An antifouling coating composition comprising a binder system which comprises:

(A) a silyl ester copolymer comprising a triisopropyl silyl methacrylate monomer;

(B) a silyl ester copolymer comprising a triisopropyl silyl acrylate monomer; and (C) 5 to 40 wt% of a monocarboxylic acid or derivative thereof;

wherein components (A) and (B) are different and the weight ratio of (A):(B) is in the range 55:45 to 95:5.
2. An antifouling coating composition as claimed in claim 1 wherein the silyl ester copolymer (A) and/or the silyl ester copolymer (B) further comprises at least one hydrophilic monomer.
3. An antifouling coating composition as claimed in claim 2, wherein the silyl ester copolymer (A) and/or the silyl ester copolymer (B) comprises:

a compound of Formula (I)

⁰ (I)

1 2 wherein R is hydrogen or methyl, R is a cyclic ether (such as oxolane, oxane, dioxolane, dioxane optionally alkyl substituted) and X is a C1-C4 alkylene; and/or a compound of Formula (II)

R³

⁰ (Π)

3 4 wherein R is hydrogen or methyl, and R is a C3-Cl8 substituent with at least one oxygen or nitrogen atom, preferably at least one oxygen atom; and optionally one or more monomers of Formula (III)

R⁵

o (III) wherein R⁵ is hydrogen or methyl, and R⁶ is a C1-C8 hydrocarbyl.
4. An antifouling coating composition as claimed in claim 3 wherein in Formula (II), R⁴ is a group of formula -(CEECFEOjm-R⁷ where R⁷ is a C1-C10 alkyl or a C6-C10 aryl substituent and m is an integer in the range of 1 to 6, preferably 1 to 3.
5. An antifouling coating composition as claimed in claim 4 wherein R⁴ is a group of formula -(CFhCFhOjm-R where R is a C1-C10 alkyl substituent, preferably methyl or ethyl, and m is an integer in the range of 1 to 3, preferably 1 or 2.
6. An antifouling coating composition as claimed in any of claims 3 to 5 wherein the silyl ester copolymer (A) and/or the silyl ester copolymer (B) comprises one or more of 2-methoxyethyl acrylate, 2-methoxyethyl methacrylate, 2ethoxyethyl methacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2ethoxyethoxy)ethyl methacrylate, tetrahydrofurfuryl acrylate, and tetrahydrofurfuryl methacrylate.
7. An antifouling coating composition as claimed in any preceding claim, wherein the monocarboxylic acid or derivative thereof comprises a C6-C20 cyclic monocarboxylic acid, wherein said cyclic monocarboxylic acid is preferably rosin or a derivative or metal salt thereof, e.g. gum rosin.
8. An antifouling coating composition as claimed in any preceding claim further comprising one or more biocides.
9. An antifouling coating composition as claimed in any preceding claim, where the binder system comprises 20 to 70 wt% (dry solids) of the silyl ester copolymer (A) based on the total weight of the binder system.
10. An antifouling coating composition as claimed in any preceding claim, wherein the binder system comprises 2 to 45 wt% (dry solids) of the silyl ester copolymer (B) based on the total weight of the binder system.
11. An antifouling coating composition as claimed in any preceding claim, further comprising at least one acrylic copolymer (D) which is different to the silyl ester copolymers (A) and (B).
12. An antifouling coating composition as claimed in any preceding claim wherein said composition comprises less than 15 wt% of any silyl ester copolymers other than copolymers (A) and (B).
13. An antifouling coating composition as claimed in any preceding claim, wherein, when combined, copolymers (A) and (B) have a glass transition temperature (Tg) of more than 10 °C and less than 70 °C.
14. A process for protecting an object from fouling, said process comprising coating at least a part of said object which is subject to fouling with an antifouling coating composition as claimed in any of claims 1 to 13.
15. An object coated with the antifouling coating composition as claimed in any of claims 1 to 13.