WO2015097240A2

WO2015097240A2 - Block copolymer and method of preparation

Info

Publication number: WO2015097240A2
Application number: PCT/EP2014/079229
Authority: WO
Inventors: Kalsani VENKATESHWARLU; Steven Edward BOWLES
Original assignee: Ppg Coatings Europe B.V.
Priority date: 2013-12-24
Filing date: 2014-12-23
Publication date: 2015-07-02
Also published as: WO2015097240A3

Abstract

A process for producing a block copolymer binder (A and B blocks) which involves sequentially polymerizing the monomers of one of block A or of block B and polymerizing the monomers of the other block bonded to the first polymer block. The polymerization of each polymer block is carried out by controlled radical polymerization techniques. The resulting block copolymer binder and marine anti-fouling coating compositions based on the binder are also disclosed.

Description

Block Copolymer and Method of Preparation

The present invention relates to novel antifouling coating compositions, binders useful in such coating compositions, processes for their production, and substrates coated with such coatings. In particular, the invention relates to coating compositions with improved properties in relation to the non-adherence or removal of fouling organisms, and to improved methods for the production of binders useful in such coatings.

The adhesion of micro-organisms, plants, and animals to surfaces, particularly surfaces exposed to water which contains such organisms, is referred to as fouling. The presence of fouling on submerged structures can lead to a reduction in their performance. For example, if the surface is the hull of a ship, the increase in frictional resistance caused by the adhesion of organisms such as barnacles to the surface can lead to a reduction in the fuel efficiency of the ship. In response, antifouling coatings have been developed and are used to combat the detrimental effects of such fouling.

Traditionally, there are several ways that an antifouling coating composition can be designed to prevent the adhesion and buildup of fouling agents on a surface (antifouling coating).

Firstly, the coating may be designed to slowly degrade over time when in contact with fresh water or sea water, usually by slow hydrolysis of the binder within the coating, causing organisms adhered to the surface to gradually fall off the surface. This mode of adhesion prevention is often referred to as "self-polishing" and such coatings are often referred to as self-polishing coatings.

Secondly, the coating may rely on low-surface energy to prevent fouling organisms from adhering to the surface of the coated substrate. These types of coatings are often referred to as "fouling release" coatings.

Finally, the coating may contain a biocide agent which serves to poison organisms which may become attached to the surface, thus causing the organism to die and fall off the surface. This mode of adhesion prevention is often referred to as "antifouling" and such coatings are often referred to as antifouling coatings.

Coatings which combine the above mentioned antifouling techniques are also available. For example, self-polishing coatings may also incorporate biocidal materials which are released into the environment upon hydrolysis and which further reduce the ability of marine organisms to attach to underwater surfaces. These exemplary dual function coatings are often referred to as self-polishing antifouling coatings.

Conventional antifouling coatings, as described above, are primarily composed of one or more biocides incorporated into a paint matrix. One such family of coatings, those based on organotin (TBT) polymers, have now been banned by legislation. Further, several countries have regulated the amount of other metals, such as copper, which are commonly incorporated into antifouling coatings for their biocidal properties or are used as catalysts during binder synthesis. As such, there is generally a desire to find alternatives for TBT polymers and/or to reduce the levels of regulated metals, such as copper, in antifouling coatings. In addition to the selection of antifouling and/or self-polishing components, the binder used in these coatings should also be considered. The term "binder" refers to the component or components of a coating that, upon cure, form a continuous film on the coated substrate. As such, the present invention provides an improved binder for marine self-polishing, antifouling, and/or fouling release coatings (i.e., antifouling coatings). The present invention also provides improved methods for the synthesis of such binders, and improved coating compositions comprising such binders, wherein the cured or dried coating minimizes adhesion of marine organisms.

Polymeric binders according to the present invention may be suitable for use in antifouling coatings which (i) may be used without need for further purification, (ii) are capable of film-forming, (iii) are low in copper content, and/or (iv) provide good antifouling behaviour in use. The invention is also directed to antifouling coating compositions including these polymeric binders, and substrates coated with such compositions. For instance, surfaces such as metal, such as a steel surface (e.g., underwater structures such as a ship's hull, an oil rig, or a dock), may be coated with the compositions of the invention.

According to the present invention there are provided methods and compositions as set forth in the description provided herein and in the appended claims. Other features of the invention will be apparent from the dependent claims.

The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each exemplary embodiment of the invention, as set out herein, are also applicable to any other aspects or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments.

Throughout this specification, the term "comprising" or "comprises" means including the component(s) specified but not to the exclusion of the presence of other components. The term "consisting essentially of or "consists essentially of means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention. Typically, when referring to compositions, a composition consisting essentially of a set of components will comprise less than 5% by weight, typically less than 3% by weight, more typically less than 1% by weight of non- specified components. The term "consisting of or "consists of means including the components specified but excluding other components.

Whenever appropriate, depending upon the context, the use of the term "comprises" or "comprising" may also be taken to include the meaning "consists essentially of or "consisting essentially of, and also may also be taken to also include the meaning "consists of or "consisting of.

The present invention provides a process for producing a block copolymer binder comprising at least two different polymer blocks A and B, the process comprising sequentially:

i) polymerizing the monomers of one of block A or of block B to produce a first polymer block; and

ii) polymerizing the monomers of the other of block A or of block B in the presence of the first polymer block to produce a second polymer block bonded to the first polymer block,

wherein the polymerization of each polymer block is carried out by controlled radical polymerization techniques using a catalyst comprising a chelated copper halide.

The controlled radical polymerization technique of the present invention may be an atom transfer radical polymerization process.

As used herein, the term "controlled radical polymerization" and related terms such as "controlled radical polymerization technique(s)" includes, but is not limited to, atom transfer radical polymerization (ATRP), single electron transfer polymerization (SETP), reversible addition- fragmentation chain transfer (RAFT), and nitroxide- mediated polymerization (NMP). Controlled radical polymerization, such as ATRP, is described generally as a "living polymerization," i.e., a chain-growth polymerization that propagates with essentially no chain transfer and essentially no chain termination. The molecular weight of a polymer prepared by controlled radical polymerization can be controlled by the stoichiometry of the reactants, such as the initial concentration of monomer(s) and initiator(s). In addition, controlled radical polymerization also provides polymers having characteristics including, but not limited to: narrow molecular weight distributions, such as polydispersity index (PDI) values less than 2.5; and/or well defined polymer chain structure, such as block copolymers and alternating copolymers, with some embodiments.

For the purposes of a non-limiting illustration of a controlled radical polymerization processes, the ATRP process is described in further detail as follows. The ATRP process can be described generally as including: polymerizing one or more radically polymerizable monomers in the presence of an initiation system; forming a polymer; and isolating the formed polymer. The initiation system may include: an initiator having at least one radically transferable atom or group; a transition metal compound, such as a catalyst, which participates in a reversible redox cycle with the initiator; and a ligand, which coordinates with the transition metal compound.

The term "ATRP process", as used herein, also includes, but not exclusively, reverse ATRP processes, "activators generated by electron transfer" (AGET) ATRP, "initiators for continuous activator regeneration" (ICAR) ATRP, and "activators regenerated by electron transfer" (ARGET) ATRP. See, for example, Patten, T. E. & Matyjaszewski, K. (1998), "Atom Transfer Radical Polymerisation and the Synthesis of Polymeric Materials", Adv. Materials 10:901.

The term "activator regenerated by electron transfer" or "ARGET", as used herein, includes an ATRP process which uses non-initiating reducing agents, typically in large excess, to continuously regenerate the activator allowing very low concentrations of the catalyst (i.e., transition metal) while maintaining control over polymerization.

In an exemplary embodiment of the present invention, the ATRP process is an ARGET polymerization process. See, for example, Min, K., Gao, H., & Matyjaszewski, K. (2007), "Use of Ascorbic Acid as Reducing Agent for Synthesis of Weil-Defined Polymers by ARGET ATRP", Macromolecules 40: 1789-1791. An initiation system, or initial reaction mixture, for an ATRP process of the present invention may comprise, in a solvent, a functional initiator and a catalyst chelated by a ligand. The monomers and optional co-monomers for polymerization may be added to this initial reaction mixture in order to progress the synthesis of the desired block copolymer.

When the ATRP process is an ARGET polymerization process, a reducing agent may be added to the initial reaction mix along with the monomers and optional co- monomers.

Hence, step (i) of an ARGET process according to the present invention may comprise adding monomers of the first polymer block and a first reducing agent to the initial reaction mixture to form a second reaction mix, and step (ii) may comprise adding monomers of the second polymer block and a second reducing agent to the second reaction mixture, after the first block copolymer has formed, to form a final reaction mix.

Any suitable solvent may be employed for carrying out the reaction. Examples include toluene, 1,4-dioxane, xylene, anisole, DMF, DMSO, water, methanol, acetonitrile, chloroform. Alternatively, solvent may be dispensed with and bulk monomer may be used as solvent in some cases.

The catalyst chelated by a ligand may be a chelated copper halide, such as chelated copper bromide. The final reaction mix may comprise from lppm to lOOppm by weight of the chelated copper halide. It will be understood that the copper halide may be in an activated divalent state, or a deactivated monovalent state, but will typically be added to the reaction in its deactivated divalent form with activation effected by the reducing agent. The chelated copper halide may have, as chelating agent, a ligand selected from Me₆TREN (tris[2-(dimethylamino)ethyl]amine),

EH₆-TREN (tris[2-(di(ethylhexylacryl)amino)ethyl]amine),

PMDETA (N,N,N',N",N"-pentamethyldiethylenetriamine),

TPMA (Tris(2-pyridylmethyl)amine), and dNbpy (4,4'-di-(5-nonyl)-2,2'-bipyridine), or mixtures thereof,

preferably EH₆-TREN, which has the formula:

The functional initiator may be an organic halide, preferably an alkyl bromide, preferably present at from 0.1% to 5% by weight of the final reaction mix.

The first and second reducing agents may be independently selected from tin (II) 2- ethylhexanoate, glucose, ascorbic acid, hydrazine, and phenyl hydrazine. These reducing agents have the benefit of low toxicity. The first and second reducing agents may be the same reducing agent, optionally both tin (II) 2-ethylhexanoate, optionally at from 1% to 15% by weight of the final reaction mix.

The first polymer block may be block A. Alternatively, the first polymer block may be block B.

As used herein, the terms "monomer unit" and "monomer residue" are interchangeable, and refer to the units in the polymer chains after polymerization, derived from the monomers used for forming the polymer chains.

At least 50% of the monomer units in block A may be monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic, and/or phosphonic acids, wherein at least some or all of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group. At least 50% of the monomer units in block B may be monomer units (b), which are monomer units other than monomer residues (a).

Monomer units (a) are monomer residues of ethylenically unsaturated carboxylic, sulfonic or phosphonic acids, and the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group, as set out hereinbefore. Monomer units (a) may also be monomer residues of ethylenically unsaturated carboxylic, sulfonic or phosphonic acids, wherein at least some of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group

The monomer residues (a) of polymer block A may include acrylic, (Ci-Cs alk)acrylic, itaconic, maleic, fumaric or crotonic acid, or the sulfonic or phosphonic acid equivalents thereof, with a silyl ester group containing at least 3 silicon atoms.

The silyl group may be represented by formula (I):

-(SiCR^-O Si-CR^R³) (I) wherein each R⁴ and R⁵ is independently selected from -0-SiR¹R²R³, or -O-

or is hydrogen or hydroxyl, or is independently selected from a C1-C20 hydrocarbyl radical; and wherein R¹, R² and R³ each independently represent hydrogen, hydroxyl, or are independently selected from a C1-C20 hydrocarbyl radical. Preferably when R⁴ or R⁵ is the radical -0-(SiR⁴R⁵0)_n-SiR¹R²R³, R⁴ and R⁵ within that radical are not themselves -0-(SiR⁴R⁵0)„-SiR¹R²R³. Further, each n independently represents a number of -Si(R⁴)(R⁵)-0- units from 1 to 1000 with the proviso that, when no R⁴ and R⁵ group present in the silyl group includes a silicon atom, n is at least 2. The monomers providing residues (a) of polymer block A may be monomers having the following chemical formula:

bis(trimethylsiloxy) methylsilylmethacrylate, MATM2. The monomers providing residues (a) of polymer block A may be monomers the following chemical formula:

trimethylsiloxy bis(dimethylsiloxy)methacrylate, MADM3. The monomer units (or residues) (b) may be derived from monomers polymerizable or copolymerizable to form polyesters, polyurethanes, polyethers, polyacrylics, polyvinyls, polyepoxides, polyamides, polyureas and copolymers thereof. Preferably, the monomer units (b) may be methylmethacrylate units. Thus, the present invention also provides a process for producing a block copolymer binder comprising at least two different polymer blocks A and B, wherein at least 50% of the monomer units in block A are monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic and/or phosphonic acids, wherein at least some or all of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group, the process comprising sequentially:

ii) polymerizing the monomers of the other of block A or of block B in the presence of the first polymer block to produce a second polymer block bonded to the first polymer block,;

wherein the polymerization of each polymer block is carried out by controlled radical polymerization techniques using a catalyst comprising a chelated copper halide. The process for producing a block copolymer binder of the present invention is typically highly controllable and commercially viable for bulk production of the block copolymer binders set out herein. The use of a controlled radical polymerization technique may reduce the concentration of unreacted monomers, and thus reduces or removes the need for post-synthesis purification.

Further, the novel chelated copper halide catalyst reduces the amount of copper used in the process, and thus provides a block copolymer binder without the need for post- synthesis purification of the synthesis product to reduce or remove copper (other than solvent removal if required). Typical prior art routes for monomer and/or copper removal can lead to acid-degradation of the silyl ester groups of polymer block A. Thus, the invention provides a novel, significantly un-degraded polymer binder having low copper content. Further, the process for the synthesis of a block copolymer binder of the present invention proceeds at a rate that is much faster that prior art processes (e.g. hours vs. days), and at a greatly reduced cost, due largely in part to the inventive use of chelated copper halide catalysts. Additionally, the ARGET process described herein allows for reduced catalyst concentrations through the use of a non-initiating reducing agent which may continuously regenerate the catalyst (e.g., reduce the copper to the active Cu(I) form) in the ATRP process.

The present invention also provides a block copolymer binder obtained or obtainable by the processes of the present invention. The block copolymer binder may comprise 50ppm by weight or less of copper, preferably 30 ppm by weight or less of copper.

The present invention also provides a block copolymer binder comprising at least two different polymer blocks A and B, wherein at least 50% of the monomer units in block A are monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic and/or phosphonic acids, and wherein at least some or all of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group, and wherein the block copolymer binder comprises 50ppm by weight or less of copper, preferably 30 ppm by weight or less of copper. The block copolymer binder of the invention may be in a solid form which may not have been subjected to reaction with acid following polymerization.

The block copolymer binder of the present invention may be further modified by chemical modification selected from esterification, hydrogenation, hydrolysis, quaternization, sulfonation, hydroboration, oxidation, epoxidation, chloro/bromo- methylation and hydrosilylation. The present invention also provides a coating composition comprising a block copolymer binder as described above, and optionally an antifouling-effective amount of at least one biocide. Suitably, within the composition, the exact amount of effective binder will depend on the application. Typically, however, the binder may represent from 1-99% by weight, preferably 5-80% by weight, more preferably 7.5-50%) by weight, most preferably 10- 40%o by weight, for example 15-30% by weight, e.g. 20%> by weight, of the composition.

The present invention also provides a substrate coated with a coating of an antifouling coating composition of the present invention.

The present invention also provides a marine vessel or marine structure partially or fully coated with a coating of an antifouling coating composition of the present invention. As used herein, a "marine vessel" or "marine structure" includes any vessel or structure designed to travel or reside in fresh water or salt water, and includes at least ships, ship hulls, boats, boat hulls, submarines, tankers, tanker hulls, oil rigs, propellers, rudders, keels, centerboards, fins, hydrofoils, deck surfaces, buoys, piers, wharves, jetties, fishing nets, cooling system surfaces, cooling water intake or discharge pipes, nautical beacons, floating beacons, floating breakwaters, docks, pipes, pipelines, tanks, water pipes in power stations, seaside industrial plants, fish preserving structures, aquatic constructions, port facilities, bridges, bells, plumbs, wheels, cranes, dredges, pumps, valves, wires, cables, ropes, ladders, pontoons, transponders, antennae, barges, periscopes, snorkels, gun mounts, gun barrels, launch tubes, mines, torpedoes and depth charges.

Preferably, at least 80% of the monomer units in block B of the present invention are monomer units other than those of type (a), more preferably, at least 95%, most preferably, at least 99%, especially 100% of the monomer units in block B are monomer units other than those of type (a).

Advantageously, the block copolymer of the invention has a lower surface energy when coated on a substrate than the corresponding statistical (random) copolymer formed of the same monomers as those of block A and B, providing an enhanced fouling release property in the coating.

Polymer blocks A and/or B may be homopolymer blocks or copolymer blocks, (i.e. a polymer block derived from two or more monomers). Preferably, at least 80% of the monomer units of block A are monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic and/or phosphonic acids having silyl ester side groups containing at least 3 silicon atoms in the silyl group, more preferably, at least 90%>, most preferably, 100%.

For the avoidance of doubt, the polymer block A of the present invention may be obtained from polymerization of the silyl ester of the relevant acid monomer or the acid groups of the relevant acid monomer residues may be esterified post polymerization. It will be appreciated that the post polymerization esterification may not necessarily be complete so that some of the acid residues in block A may not be silylated with the silyl group. Typically, however, at least 55% of the monomer residues in block A are silylated with the silyl group, more preferably, at least 75%, most preferably, at least 90%. Typically, between 60-100%) of the residues in block A are silyl ester residues, more typically, 80-100%), most typically, 90-100%), especially, 100%. Typically, the polymer block A of the present invention may be obtained from polymerization of the silyl ester of the relevant acid monomer.

In relation to block A, the ethylenically unsaturated carboxylic acid residues having the silyl ester side group may be derived from any other polymerizable ethylenically unsaturated monomer or polymer derived therefrom having acid functionality on the side chains thereof and capable of forming the silyl ester thereof such as itaconic, maleic, fumaric, crotonic. In addition, the invention extends to suitable sulfonic or phosphonic acid equivalents of the above acrylic and other monomers. An ethylenically unsaturated carboxylic acid is preferred. However, (alk)acrylic acid such as acrylic acid or (Ci-Cs alk) acrylic acid (e.g. methacrylic acid) mentioned above, more preferably, methacrylic acid residues, are preferred. Accordingly, the polymer block A may be acrylic based or derived from other suitable monomers. More generally, the polymer block A of the present invention may be at least partially derived from any known unsaturated monomer or polymer having acid groups in the side chains or the terminal groups, more preferably, acid groups of formula -Z(OH)_x wherein X is an integer from 1-3 and Z is selected from the following:

Preferably, the unsaturated carboxylic, sulfonic, or phosphonic acid is acrylic or (C_1-8 alk)acrylic acid, more preferably, acrylic acid or methacrylic acid, most preferably, methacrylic acid.

Preferably, the silyl group of the silyl ester monomer residue (a) is represented by formula (I):

(SiCR^-O Si-CR^R³) wherein each R⁴ and R⁵ is independently selected from -0-SiR¹R²R³, or -O- (SiR⁴R⁵0)_n-SiR¹R²R³, or may be hydrogen or hydroxyl, or may be independently selected from a C1-C20 hydrocarbyl radical; and R¹, R² and R³ each independently represent hydrogen, hydroxyl, or may be independently selected from a C1-C20 hydrocarbyl radical; and preferably when R⁴ or R⁵ is the radical -0-(SiR⁴R⁵0)_n- SiR¹R²R³, R⁴ and R⁵ within that radical are not themselves -0-(SiR⁴R⁵0)_n-SiR¹R²R³; and wherein each n independently represents a number of -Si(R⁴)(R⁵)-0- units from 1 to 1000 with the proviso that when no R⁴ and R⁵ group present in the silyl group includes a silicon atom, n is at least 2.

A C1-C20 hydrocarbyl radical herein represents an alkyl, aryl, alkoxyl, acyl, aryloxyl, alkenyl, alkynyl, aralkyl, or aralkyloxyl radical that may, where possible, include branched, linear, or cyclic parts optionally substituted by one or more substituents independently selected from the group comprising hydroxyl, silyl, -0-SiR¹R²R³, -0-(SiR⁴R⁵0)_n-SiR¹R²R³, halogen, nitro, amino (preferably, tertiary amino), or amino alkyl radicals, and/or interrupted by one or more nitrogen, oxygen, sulphur, -C(O)-, -C(0)0- or -C(0)NH- radicals, and/or terminated by -C(0)-H, -C(0)OH, or -C(0)NH₂ radicals. Of the above, a Ci-Cio hydrocarbyl radical is more preferred, particularly a C1-C4 aliphatic hydrocarbyl radical, more particularly, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tertiary butyl, or methoxyl, and most particularly, methyl.

Preferably, R⁴ and R⁵ each independently represent an alkyl, an alkoxyl, an aryl, an hydroxyl group, a -O-SiR^R³, or a -CHSiR O SiR^R³ group, wherein R¹, R², R³, R⁴ and R⁵ are as defined above and wherein preferably, n = 1-50, more preferably n = 1-10, for example n = 1, 2, 3, 4 or 5.

More preferably, R⁴ and R⁵ are each independently selected from the group comprising an alkyl group, a hydroxyl group, an alkoxyl group, a -0-SiR¹R²R³ group, or a -0-(SiR⁴R⁵0)_n-SiR¹R²R³ group.

Most preferably, R⁴ and R⁵ are each independently selected from the group comprising an alkyl group, a -0-(SiR⁴R⁵0)_n-SiR¹R²R³ group, and a -0-SiR¹R²R³ group, as previously defined. According to the present invention, R¹, R², R³, R⁴ and R⁵ may each be independently methyl, ethyl, propyl, isopropyl, isobutyl, n-butyl, sec-butyl, and t-butyl. Preferably, when they are alkyl groups, R⁴ and R⁵ are methyl or ethyl, more preferably methyl, most preferably, one or both R⁴ and R⁵ are methyl. When R¹, R² and R³ are alkyl groups they are preferably independently Ci-Cs alkyl groups, more preferably C1-C4 alkyl groups, most preferably methyl, isopropyl and n- butyl. The alkyl groups may be branched or linear and, optionally, substituted as aforesaid. When R⁴ or R⁵ are alkoxyl, they are preferably Ci-Cs oxyl groups which may be branched or linear, more preferably C1-C4 oxyl groups, most preferably a methoxyl group. Preferably, when any one of the R⁴ or R⁵ groups is selected as -0-SiR¹R²R³ or -0-(SiR⁴R⁵0)_n-SiR¹R²R³, and such groups are substituted, the substitution is at the groups and is preferably a substitution by hydroxyl, silyl, halogen, amino, or amino alkyl.

Preferably, at least one of R⁴ or R⁵ in general formula (I), notably at least one of R⁴ or R⁵ attached to the Si adjacent to the polymer backbone in general formula (I), is selected from -0-(SiR⁴R⁵0)_n-SiR¹R²R³ or -0-SiR¹R²R³, preferably at least one of R⁴ or R⁵, notably at least one of R⁴ or R⁵ attached to the Si adjacent to the polymer backbone in general formula (I), is -0-SiR¹R²R³, more preferably, both R⁴ and R⁵ attached to the same Si in general formula (I) are selected from -0-(SiR⁴R⁵0)_n- SiR¹R²R³ or -0-SiR¹R²R³, notably both R⁴ and R⁵ attached to the Si adjacent to the polymer backbone in general formula (I) are selected from -0-(SiR⁴R⁵0)_n-SiR¹R²R³ or -0-SiR¹R²R³, most preferably both R⁴ and R⁵ attached to the same Si in general formula (I) are -0-SiR¹R²R³, notably both R⁴ and R⁵ attached to the Si adjacent to the polymer backbone in general formula I are -O-SiR^R³.

Suitable examples of silyl ester monomers (a) for block A include MAD3M and MATM2 (trimethylsiloxy bis(dimethylsiloxy)methacrylate and bis(trimethylsiloxy) methylsilylmethacrylate, respectively).

Suitably, as noted above, each n independently represents a number of -Si(R⁴)(R⁵)-0- units, and further, each n independently represents from 1 to 1000, preferably in the range 1 to 500, more preferably in the range 1 to 50, most preferably in the range 1 to 20, for example, n=l, 2, 3, 4 or 5, e.g. n=l .

Preferably, the side chains of formula (I) are present on 1-100% of the residual monomer units in the polymer block A, more preferably, 50-100%, most preferably, 80-100% of the monomer units.

Preferably, the group of formula (I) is present in the block copolymer in the range of 1-99%) w/w, more preferably, 5-75%> w/w, most preferably 15-55%) w/w. In the case where not all the monomer units of block A are monomer residues of type (a), suitable comonomers for block A include (i) those that contain functional groups that may be reactive with optional functional groups of the block B polymer, and (ii) those that do not include such functional groups.

Examples of functional group-containing monomers (i) that are suitable for use in preparing the block A polymer are monomers containing hydroxyl groups, amine groups, epoxy groups, and carboxylic acid groups, to name a few. Examples of monomers containing hydroxyl groups are hydroxyalkyl functional acrylates and methacrylates such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4- hydroxybutyl methacrylate and the like. Mixtures of these hydroxyalkyl functional monomers may also be used. Examples of amine group-containing monomers are t- butylaminoethyl (meth)acrylate and aminoethyl (meth)acrylate. Examples of carboxylic acid group-containing monomers are (meth)acrylic acid, crotonic acid and itaconic acid. Examples of epoxy group-containing monomers include glycidyl (meth)acrylate.

Examples of monomers (ii) are vinyl aromatic compounds and alkyl or aryl esters of (meth)acrylic acid or anhydride. Suitable vinyl aromatic compounds include styrene which is preferred, alpha-methylstyrene, alpha-chloromethyl styrene and vinyl toluene. Suitable alkyl esters of acrylic and methacrylic acid or anhydride include those wherein the alkyl portion of the ester contains from 1 to 30, preferably 4 to 30, carbon atoms, those in which the alkyl group is linear or branched or aliphatic, including cycloaliphatic. Suitable specific monomers include alkyl acrylates such as methyl acrylate, n-butyl acrylate and t-butyl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, cyclohexyl acrylate, t-butyl cyclohexyl acrylate, trimethyl cyclohexyl acrylate, lauryl acrylate, and the like; alkyl methacrylates, including methyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate (which is preferred), isobornyl methacrylate, cyclohexyl methacrylate, t-butyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, and lauryl methacrylate. Suitable aryl esters include acrylate and methacrylate esters of secondary and tertiary butylphenol substituted in the 2, 3, or 4 position and nonylphenol. Preferably, both block A and block B, and any additional polymer blocks, are independently homopolymer blocks.

Suitable monomers for block B include, but are not limited to, those monomers which are polymerizable or copolymerizable to form polyesters, polyurethanes, polyethers, polyacrylics, polyvinyls, polyepoxides, polyamides, polyureas and copolymers thereof. Suitable monomers or comonomers for block B include (i) those that contain functional groups that may or may not be reactive with optional functional groups of the block A polymer, and (ii) those that do not include such functional groups.

The polymer block B may comprise at least one reactive functional group selected from a hydroxyl group, a carboxyl group, an isocyanate group, a blocked isocyanate group, a primary amine group, a secondary amine group, an amide group, a carbamate group, a urea group, a urethane group, a vinyl group, an unsaturated ester group, a maleimide group, a fumarate group, an anhydride group, a hydroxy alkylamide group, and an epoxy group. The polymer block B can comprise a mixture of any of the foregoing reactive functional groups.

Polymers suitable for use as the at least one reactive functional group-containing polymer block B can include any of a variety of functional polymers known in the art. For example, suitable hydroxyl group-containing polymers can include acrylic polyols, polyester polyols, polyurethane polyols, polyether polyols, and mixtures thereof. In a particular embodiment of the present invention, the film-forming block polymer B is an acrylic polyol having a hydroxyl equivalent weight ranging from 1000 grams to 100 grams per solid equivalent, preferably 500 grams to 150 grams per solid equivalent.

Suitable hydroxyl group and/or carboxyl group-containing acrylic polymers for block B can be prepared from polymerizable ethylenically unsaturated monomers and are typically copolymers of (meth)acrylic acid and/or hydroxylalkyl esters of (meth)acrylic acid with one or more other polymerizable ethylenically unsaturated monomers such as alkyl esters of (meth)acrylic acid including methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate and 2-ethyl hexylacrylate, and vinyl aromatic compounds such as styrene, alpha-methyl styrene, and vinyl toluene. As used herein, "(meth)acrylate" and like terms is intended to include both acrylates and methacrylates. According to the present invention, an acrylic polymer of block B can be prepared from ethylenically unsaturated beta-hydroxy ester functional monomers. Such monomers can be derived from the reaction of an ethylenically unsaturated acid functional monomer, such as monocarboxylic acids, for example, acrylic acid, and an epoxy compound which does not participate in the free radical initiated polymerization with the unsaturated acid monomer. Examples of such epoxy compounds include glycidyl ethers and esters. Suitable glycidyl ethers include glycidyl ethers of alcohols and phenols such as butyl glycidyl ether, octyl glycidyl ether, phenyl glycidyl ether and the like. Suitable glycidyl esters include those which are commercially available from Shell Chemical Company under the trade name CARDURA E, and from Exxon Chemical Company under the trade name GLYDEXX-10. Alternatively, the beta-hydroxy ester functional monomers can be prepared from an ethylenically unsaturated, epoxy functional monomer, for example glycidyl (meth)acrylate and allyl glycidyl ether, and a saturated carboxylic acid, such as a saturated monocarboxylic acid, for example isostearic acid.

Epoxy functional groups can be incorporated into the polymer of block B prepared from polymerizable ethylenically unsaturated monomers by copolymerizing oxirane group-containing monomers, for example glycidyl (meth)acrylate and allyl glycidyl ether, with other polymerizable ethylenically unsaturated monomers, such as those discussed above. Preparation of such epoxy functional acrylic polymers is described in detail in U.S. Patent No. 4,001,156 at columns 3 to 6, incorporated herein by reference.

Carbamate functional groups can be incorporated into the polymer of block B prepared from polymerizable ethylenically unsaturated monomers by copolymerizing, for example, the above-described ethylenically unsaturated monomers with a carbamate functional vinyl monomer such as a carbamate functional alkyl ester of methacrylic acid. Useful carbamate functional alkyl esters can be prepared by reacting, for example, a hydroxyalkyl carbamate, such as the reaction product of ammonia and ethylene carbonate or propylene carbonate, with methacrylic anhydride. Other useful carbamate functional vinyl monomers for block B include, for instance, the reaction product of hydroxyethyl methacrylate, isophorone diisocyanate, and hydroxypropyl carbamate; or the reaction product of hydroxypropyl methacrylate, isophorone diisocyanate, and methanol. Still other carbamate functional vinyl monomers may be used for block B, such as the reaction product of isocyanic acid (HNCO) with a hydroxyl functional acrylic or methacrylic monomer such as hydroxyethyl acrylate, and those described in U.S. Patent No. 3,479,328, incorporated herein by reference.

Carbamate functional groups can also be incorporated into the acrylic polymer of block B by reacting a hydroxyl functional acrylic polymer with a low molecular weight alkyl carbamate such as methyl carbamate. Pendant carbamate groups can also be incorporated into the acrylic polymer of block B by a "transcarbamoylation" reaction in which a hydroxyl functional acrylic polymer is reacted with a low molecular weight carbamate derived from an alcohol or a glycol ether. The carbamate groups exchange with the hydroxyl groups yielding the carbamate functional acrylic polymer and the original alcohol or glycol ether. Also, hydroxyl functional acrylic polymers of block B can be reacted with isocyanic acid to provide pendent carbamate groups. Likewise, hydroxyl functional acrylic polymers can be reacted with urea to provide pendent carbamate groups.

Polyester polymers are also useful in the coating compositions of the invention as the polymer block B. Useful polyester polymers typically include the condensation products of polyhydric alcohols and polycarboxylic acids. Suitable polyhydric alcohols can include ethylene glycol, neopentyl glycol, trimethylol propane, and pentaerythritol. Suitable polycarboxylic acids can include adipic acid, 1,4-cyclohexyl dicarboxylic acid, and hexahydrophthalic acid. Besides the polycarboxylic acids mentioned above, functional equivalents of the acids such as anhydrides where they exist or lower alkyl esters of the acids such as the methyl esters can be used. Also, small amounts of monocarboxylic acids such as stearic acid can be used. The ratio of reactants and reaction conditions are selected to result in a polyester polymer with the desired pendent functionality, i.e., carboxyl or hydroxyl functionality. For example, hydroxyl group-containing polyesters can be prepared by reacting an anhydride of a dicarboxylic acid such as hexahydrophthalic anhydride with a diol such as neopentyl glycol in a 1 :2 molar ratio. Where it is desired to enhance air- drying, suitable drying oil fatty acids may be used and include those derived from linseed oil, soya bean oil, tall oil (tallol), dehydrated castor oil, or Tung oil.

Carbamate functional polyesters of block B can be prepared by first forming a hydroxyalkyl carbamate that can be reacted with the polyacids and polyols used in forming the polyester. Alternatively, terminal carbamate functional groups can be incorporated into the polyester by reacting isocyanic acid with a hydroxy functional polyester. Also, carbamate functionality can be incorporated into the polyester by reacting a hydroxyl polyester with a urea. Additionally, carbamate groups can be incorporated into the polyester by a transcarbamoylation reaction. Preparations of suitable carbamate functional group-containing polyesters are those described in U.S. Patent No. 5,593,733 at column 2, line 40 to column 4, line 9, incorporated herein by reference.

Polyurethane polymers containing terminal isocyanate or hydroxyl groups also can be used as the polymer block B in the coating compositions of the invention. The polyurethane polyols or NCO-terminated polyurethanes which can be used are those prepared by reacting polyols including polymeric polyols with polyisocyanates. Polyureas containing terminal isocyanate or primary and/or secondary amine groups which also can be used are those prepared by reacting polyamines including polymeric polyamines with polyisocyanates. The hydroxyl/isocyanate or amine/isocyanate equivalent ratio is adjusted and reaction conditions are selected to obtain the desired terminal groups. Examples of suitable polyisocyanates include those described in U.S. Patent No. 4,046,729 at column 5, line 26 to column 6, line 28, incorporated herein by reference. Examples of suitable polyols include those described in U.S. Patent No. 4,046,729 at column 7, line 52 to column 10, line 35, incorporated herein by reference. Examples of suitable polyamines include those described in U.S. Patent No. 4,046,729 at column 6, line 61 to column 7, line 32 and in U.S. Patent No. 3,799,854 at column 3, lines 13 to 50, both incorporated herein by reference. Carbamate functional groups can be introduced into the polyurethane polymers of block B by reacting a polyisocyanate with a polyester having hydroxyl functionality and containing pendent carbamate groups. Alternatively, the polyurethane can be prepared by reacting a polyisocyanate with a polyester polyol and a hydroxyalkyl carbamate or isocyanic acid as separate reactants. Examples of suitable polyisocyanates are aromatic isocyanates, such as 4,4'-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate and toluene diisocyanate, and aliphatic polyisocyanates, such as 1 ,4-tetramethylene diisocyanate and 1 ,6-hexamethylene diisocyanate. Cycloaliphatic diisocyanates, such as 1 ,4-cyclohexyl diisocyanate and isophorone diisocyanate also can be employed.

Examples of suitable polyether polyols include polyalkylene ether polyols such as those having the following structural formulas (II) or (III):

wherein the substituent R is hydrogen or a lower alkyl group containing from 1 to 5 carbon atoms including mixed substituents, n has a value typically ranging from 2 to 6, and m has a value typically ranging from 8 to 100 or higher.

Exemplary polyalkylene ether polyols include poly(oxytetramethylene) glycols, poly(oxytetraethylene) glycols, poly(oxy-l ,2-propylene) glycols, and poly(oxy-l ,2- butylene) glycols. Also useful are polyether polyols formed from oxyalkylation of various polyols, for example, glycols such as ethylene glycol, 1,6-hexanediol, Bisphenol A, and the like, or other higher polyols such as trimethylolpropane, pentaerythritol, and the like. Polyols of higher functionality which can be utilized as indicated can be made, for instance, by oxyalkylation of compounds such as sucrose or sorbitol. One commonly utilized oxyalkylation method is reaction of a polyol with an alkylene oxide, for example, propylene or ethylene oxide, in the presence of an acidic or basic catalyst. Specific examples of polyethers include those sold under the names TERATHANE and TERACOL, available from E. I. Du Pont de Nemours and Company, Inc.

Preferably, polymer blocks with oxyalkylene backbone groups are excluded from block B of the present invention. In addition, preferably, polymer blocks having residues of mercaptans are also excluded from block B. Preferably, the monomer residues of block B are present in the block copolymer in the range of 5-99% w/w of the total monomer residues in the block copolymer, more preferably, 30-95% w/w, most preferably 40-70%) w/w.

Preferably, the residues (a) of block A, with silyl groups, are present in the block copolymer in the range 1-95% w/w of the total monomer residues in the block copolymer, more preferably, 5-70%> w/w, most preferably, 30-60%) w/w.

Advantageously, the present invention provides antifouling coatings with the option of reduced biocide levels and optionally with self-polishing properties. Fouling release coatings, which have a low surface energy that prevents the adhesion of marine organisms, are typically less effective for immobile underwater structures, such as a ship in harbour or a fixed underwater structure, as compared to a substrate that is mobile. Accordingly, the compositions of the present invention allow for improved antifouling performance which is effective against fouling of fixed or idle marine structures or surfaces of such.

As mentioned above, polymers of block B can be connected to block A in any of a variety of ways. For example, any of these blocks could include functional groups or unsaturation that could be utilized to react with any of a variety of other monomer residues in the other block. For example, block A or block B could contain residues of monomers such as acrylic monomers having pendant epoxy, hydroxyl, and unsaturated groups. One such preferred example connection could be obtained by ring opening a pendant epoxy group on one block by reaction with an unsaturated acid on the other block. The weight average molecular weight (Mw) of each block of the block copolymer of the invention, typically a diblock copolymer, is not particularly restricted. The Mw should be chosen so that good film forming properties are obtained. However, in general, the Mw of each block may be from 5,000 up to 500,000 Daltons, more preferably, 8,000 to 200,000 Daltons, most preferably, 10,000 to 60,000 Daltons as determined by GPC (size exclusion chromatography). Accordingly, the Mw of the block copolymer may be 10,000 to 1,000,000 Daltons, more preferably, 16,000 to 400,000 Daltons, most preferably, 20,000 to 120,000 Daltons as determined by GPC (size exclusion chromatography). The ratio of block A to block B may be from 10:90 to 90:1 by weight, for instance from 20:80 to 80:20 such as from 40:60 to 60:60, for instance 50:50

Definitions

As used herein, the term "independently", "independently selected", "independently represent" or the like indicates that each radical so described, can be identical or different. When n > 1, such as in general formula (I) for instance, then each R⁴ or each R⁵ within a particular (SiR⁴R⁵0)_n group can be the same as or different than the other R⁴ or R⁵ groups, respectively, within the particular (SiR⁴R⁵0)_n group. Moreover, if there is more than one (-SiR¹R²R³) group present, each R¹, each R², and each R³ can be the same as or different than the other R¹, R², and R³ groups present in the overall formula.

The term "alk" or "alkyl", as used herein, unless otherwise defined, relates to saturated hydrocarbon radicals being straight, branched, cyclic or polycyclic moieties or combinations thereof, and unless otherwise indicated contains 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, yet more preferably 1 to 4 carbon atoms. These radicals may be optionally substituted with a halo, cyano, nitro, OR¹⁹, OC(0)R²⁰, C(0)R²¹, C(0)OR²², NR²³R²⁴, C(0)NR²⁵R²⁶, SR²⁷, C(0)SR²⁷, C(S)NR²⁵R²⁶, aryl or Het, wherein R¹⁹ to R²⁷ each independently represent hydrogen, aryl or alkyl, and/or may be interrupted by one or more oxygen or sulphur atoms, or by silano or dialkylsilcon groups. Examples of such radicals may be independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2- methylbutyl, pentyl, iso-amyl, hexyl, cyclohexyl, 3-methylpentyl, octyl, and the like.

The term "alkenyl", as used herein, relates to hydrocarbon radicals having one or several, preferably up to 4, more preferably, 1 or 2, most preferably 1 double bond(s), being straight, branched, cyclic or polycyclic moieties or combinations thereof and containing from 2 to 18 carbon atoms, preferably 2 to 10 carbon atoms, more preferably from 2 to 8 carbon atoms, still more preferably 2 to 6 carbon atoms, yet more preferably 2 to 4 carbon atoms. These radicals may be optionally substituted with a hydroxyl, halo, cyano, nitro, OR¹⁹, OC(0)R²⁰, C(0)R²¹, C(0)OR²², NR²³R²⁴, C(0)NR²⁵R²⁶, SR²⁷, C(0)SR²⁷, C(S)NR²⁵R²⁶, aryl or Het, wherein R¹⁹ to R²⁷ each independently represent hydrogen, aryl or alkyl, and/or may be interrupted by one or more oxygen or sulphur atoms, or by silano or dialkylsilcon groups. Examples of such radicals may be independently selected from alkenyl groups which include vinyl, allyl, isopropenyl, pentenyl, hexenyl, heptenyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclo hexenyl, 1-propenyl, 2-butenyl, 2-methyl-2-butenyl, isoprenyl, farnesyl, geranyl, geranylgeranyl, and the like.

The term "alkynyl", as used herein, relates to hydrocarbon radicals having one or several, preferably up to 4, more preferably, 1 or 2, most preferably, 1 triple bond(s), being straight, branched, cyclic or polycyclic moieties or combinations thereof and having from 2 to 18 carbon atoms, preferably 2 to 10 carbon atoms, more preferably from 2 to 8 carbon atoms, still more preferably from 2 to 6 carbon atoms, yet more preferably 2 to 4 carbon atoms. These radicals may be optionally substituted with a hydroxy, halo, cyano, nitro, OR¹⁹, OC(0)R²⁰, C(0)R²¹, C(0)OR²², NR²³R²⁴, C(0)NR²⁵R²⁶, SR²⁷, C(0)SR²⁷, C(S)NR²⁵R²⁶, aryl or Het, wherein R¹⁹ to R²⁷ each independently represent hydrogen, aryl or lower alkyl, and/or may be interrupted by one or more oxygen or sulphur atoms, or by silano or dialkylsilcon groups. Examples of such radicals may be independently selected from alkynyl radicals, which include ethynyl, propynyl, propargyl, butynyl, pentynyl, hexynyl, and the like.

The term "aryl", as used herein, relates to an organic radical derived from an aromatic hydrocarbon by removal of one hydrogen, and includes any monocyclic, bicyclic or polycyclic carbon ring of up to 7 members in each ring, wherein at least one ring is aromatic. These radicals may be optionally substituted with a hydroxy, halo, cyano, nitro, OR¹⁹, OC(0)R²⁰, C(0)R²¹, C(0)OR²², NR²³R²⁴, C(0)NR²⁵R²⁶, SR²⁷, C(0)SR²⁷,

C(S)NR 25 R 26 , aryl or Het, wherein R 19 to R 27^" each independently represent hydrogen, aryl or lower alkyl, and/or may be interrupted by one or more oxygen or sulphur atoms, or by silano or dialkylsilcon groups. Examples of such radicals may be independently selected from phenyl, p-tolyl, 4-methoxyphenyl, 4-(tert-butoxy)phenyl, 3-methyl-4-methoxyphenyl, 4-fluorophenyl, 4-chlorophenyl, 3-nitrophenyl, 3- aminophenyl, 3-acetamidophenyl, 4-acetamidophenyl, 2-methyl-3-acetamidophenyl, 2-methyl-3-aminophenyl, 3-methyl-4-aminophenyl, 2-amino-3-methylphenyl, 2,4- dimethyl-3-aminophenyl, 4-hydroxyphenyl, 3-methyl-4-hydroxyphenyl, 1-naphthyl,

2- naphthyl, 3-amino- 1-naphthyl, 2-methyl-3-amino- 1-naphthyl, 6-amino-2-naphthyl, 4,6-dimethoxy-2-naphthyl, tetrahydronaphthyl, indanyl, biphenyl, phenanthryl, anthryl, or acenaphthyl and the like. The term "aralkyl", as used herein, relates to a group of the formula alkyl-aryl, in which alkyl and aryl have the same meaning as defined above and may be attached to an adjacent radical via the alkyl or aryl part thereof. Examples of such radicals may be independently selected from benzyl, phenethyl, dibenzylmethyl, methylphenylmethyl,

3- (2-naphthyl)-butyl, and the like.

The term "Het", when used herein, includes four-to-twelve-membered, preferably four-to-ten-membered ring systems, which rings contain one or more heteroatoms selected from nitrogen, oxygen, sulphur and mixtures thereof, and which rings may contain one or more double bonds or be non-aromatic, partly aromatic or wholly aromatic in character. The ring systems may be monocyclic, bicyclic or fused. Each "Het" group identified herein is optionally substituted by one or more substituents

19 20 21 selected from halo, cyano, nitro, oxo, lower alkyl, OR , OC(0)R , C(0)R , C(0)OR²², NR²³R²⁴, C(0)NR²⁵R²⁶, SR²⁷, C(0)SR²⁷ or C(S)NR²⁵R²⁶ wherein R¹⁹ to R²⁷ each independently represent hydrogen, aryl or lower alkyl. The term "Het" thus includes groups such as optionally substituted azetidinyl, pyrrolidinyl, imidazolyl, indolyl, furanyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, triazolyl, oxatriazolyl, thiatriazolyl, pyridazinyl, morpholinyl, pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, piperidinyl, pyrazolyl and piperazinyl. Substitution at Het may be at a carbon atom of the Het ring or, where appropriate, at one or more of the heteroatoms.

"Het" groups may also be in the form of an N oxide.

For the avoidance of doubt, the reference to alkyl, alkenyl, alkynyl, aryl, or aralkyl in composite groups should be interpreted according to definitions provided above. For example, the reference to alkyl in aminoalkyl or alk in alkoxyl should be interpreted as alkyl or alk as detailed above, etc.

The use of parenthesis in the terms "(alk)acrylate" or "(meth)acrylate", as used herein, optionally refers to alkacrylate, methacrylate, or the non-alk or non-meth acrylate respectively. The term "silyl", as used herein, includes

groups wherein R'-R⁵ are as defined herein and the term "silyl ester side group" means, in the case of an acid, the silyl group bonded to an oxy radical of the acid group to form an O-Si ester bond. The term "lower alkyl" or the like, as used herein, has the same definition as "alkyl" above except that it is restricted to 1 to 6 carbon atoms.

The term "block copolymer", as used herein, includes unless otherwise indicated to the contrary cyclic or linear AB diblock copolymers, ABC tri or further ABCD etc block copolymers, ABA triblock copolymers; (AB)_n star and multiblock copolymers; A_nB_n star block copolymers; and graft copolymers.

Additives

Pigments, antifouling agents, solvents, plasticizers and other additives can be added to the binders of the present invention to produce coating compositions and coatings according to the present invention; and are known in the art.

Suitable solvents for the antifouling coating composition of the present invention include acetates, ketones and non- functional group containing aromatic compounds such as ethyl acetate, butyl acetate, methylethyl ketone, methyl isobutyl ketone, ethylene glycol monoethylether acetate, methoxypropyl acetate, toluene, xylene, white spirit, ethoxypropyl acetate, ethoxyethyl propionate, methoxybutyl acetate, butyl glycol acetate, solvent naphtha, n-butanol and mixtures of these solvents. The solvents are used in a quantity of up to 70% by weight, preferably up to 40% by weight, based on the weight of the antifouling composition.

Further additives to be used if required are, for example, plasticizers such as, for example, tricresyl phosphate, phthalic diesters, or chloroparaffins; pigments such as colour pigments, bright pigments, and extender pigments and fillers, such as titanium oxide, barium sulphate, chalk, carbon black; levelling agents; thickeners; stabilizers, such as substituted phenols or organo functional silanes. Adhesion promoters and light stabilizers may also be utilised. Antifoulants (biocides), although not essential to the present invention, may be used as a component in the coating composition of the present invention and may be any of one or more conventionally known antifoulants. The known antifoulants are roughly divided into inorganic compounds, metal-containing organic compounds, and metal- free organic compounds.

Examples of the inorganic compounds include copper compounds (e.g. copper sulphate, copper powder, cuprous thiocyanate, copper carbonate, copper chloride, and the traditionally preferred cuprous oxide), zinc sulphate, zinc oxide, nickel sulphate, and copper nickel alloys. However, it will be understood that for copper-free compositions, or compositions low in copper, these are not preferred.

Examples of the metal-containing organic compounds include organo-copper compounds, organo-nickel compounds, and organo-zinc compounds. Also usable are manganese ethylene bis(dithiocarbamate) (maneb) or zinc propylene bis(dithiocarbamate) (propineb). Examples of the organo-copper compounds include copper nonylphenol-sulphonate, copper bis(ethylenediamine) bis(dodecylbenzene sulphonate), copper acetate, copper naphthenate, copper pyrithione and copper bis(pentachlorophenolate). Examples of the organo-nickel compounds include nickel acetate and nickel dimethyl dithiocarbamate. Examples of the organo-zinc compounds include zinc acetate, zinc carbamate, bis(dimethylcarbamoyl) zinc ethylene- bis(dithiocarbamate), zinc dimethyl dithiocarbamate, zinc pyrithione, and zinc ethylene-bis(dithiocarbamate). As an example of a mixed metal-containing organic compound, one can cite (polymeric) manganese ethylene bis dithiocarbamate complexed with zinc salt (mancozeb).

Examples of the metal-free organic compounds include N-trihalomethyl thiophthalimides, trihalomethyl thiosulphamides, dithiocarbamic acids, N- arylmaleimides, 3 -(substituted amino)- 1,3 thiazolidine-2,4-diones, dithiocyano compounds, triazine compounds, oxathiazines and others.

Examples of the N-trihalomethyl thiophthalimides include N-trichloromethyl thiophthalimide and N-fluorodichloromethyl thiophthalimide.

Examples of the dithiocarbamic acids include bis(dimethylthiocarbamoyl) disulphide, ammonium N-methyldithiocarbamate, and ammonium ethylene-bis(dithiocarbamate).

Examples of trihalomethylthiosulphamides include N-(dichlorofluoromethylthio)- N' ,N'-dimethyl-N-phenylsulphamide and N-(dichlorofluoromethylthio)-N' ,Ν'- dimethyl-N-(4-methylphenyl)sulphamide.

Examples of the N-arylmaleimides include N-(2,4,6-trichlorophenyl)maleimide, N-4 tolylmaleimide, N-3 chlorophenylmaleimide, N-(4-n-butylphenyl)maleimide, N- (anilinophenyl)maleimide, and N-(2,3-xylyl)maleimide.

Examples of the 3 -(substituted amino)- l,3-thiazolidine-2,4-diones include 2- (thiocyanomethylthio)-benzothiazole, 3-benzylideneamino- 1 , 3-thiazolidine-2,4- dione, 3-(4-methylbenzylideneamino)- 1 ,3-thiazolidine-2,4-dione, 3-(2-hydroxy benzylideneamino)-l,3-thiazolidine-2,4-dione,3-(4-dimethylaminobenzylideamino)-

1.3- thiazolidine-2,4-dione, and 3-(2,4-dichlorobenzylideneamino)- 1 ,3-thiazolidine-

2.4- dione.

Examples of the dithiocyano compounds include dithiocyanomethane, dithiocyanoethane and 2,5-dithiocyanothiophene. Examples of the triazine compounds include 2-methylthio-4-butylamino-6- cyclopropylamino-s-triazine. Examples of oxathiazines include 1,4,2-oxathiazines and their mono- and di-oxides such as disclosed in PCT Patent Application Publication No. WO 98/05719: mono- and di-oxides of 1,4,2-oxathiazines with a substituent in the 3 position representing (a) phenyl; phenyl substituted with 1 to 3 substituents independently selected from hydroxyl, halo, Cl-12 alkyl, C5-6 cycloalkyl, trihalomethyl, phenyl, C1-C5 alkoxy, CI -5 alkylthio, tetrahydropyranyloxy, phenoxy, CI -4 alkyl carbonyl, phenyl carbonyl, CI -4 alkylsulfmyl, carboxy or its alkali metal salt, CI -4 alkoxycarbonyl, CI -4 alkylaminocarbonyl, phenylamino carbonyl, tolylaminocarbonyl, morpholinocarbonyl, amino, nitro, cyano, dioxolanyl or CI -4 alkyloxyiminomethyl; naphthyl; pyridinyl; thienyl; furanyl; or thienyl or furanyl substituted with one to three substituents independently selected from C1-C4 alkyl, CI -4 alkoxy, CI -4 alkylthio, halo, cyano, formyl, acetyl, benzoyl, nitro, C1-C4 alkoxycarbonyl, phenyl, phenylaminocarbonyl and CI -4 alkyloxyiminomethyl; or (b) a substituent of generic formula:

wherein X is oxygen or sulphur; Y is nitrogen, CH or C(Cl-4 alkoxy); and the C6 ring may have one CI -4 alkyl substituent; a second substituent selected from CI -4 alkyl or benzyl being optionally present in position 5 or 6.

Other examples of the metal-free organic compounds include 2,4,5,6-tetrachloroiso phthalonitrile, Ν,Ν-dimethyl-dichlorophenylurea, 4,5-dichloro-2-n-octyl-4- isothiazo line-3 -one, N,N-dimethyl-N ' -phenyl-(N-fluorodichloromethylthio)- sulfamide, tetramethylthiuramdisulphide, 3-iodo-2-propinylbutyl carbamate, 2- (methoxylcarbonylamino)benzimidazole, 2,3 ,5 ,6-tetrachloro-4-(methylsulphonyl) pyridine, diiodomethyl-p-tolyl sulphone, phenyl(bispyridine) bismuth dichloride, 2- (4-thiazolyl)benzimidazole, dihydroabietyl amine, N-methylol formamide and pyridine triphenylborane. According to a preferred embodiment, the use as antifoulant of the oxathiazines disclosed in PCT Patent Application Publication No. WO 95/05739 has the added advantage (disclosed in European Patent Application Publication No. EP-A-823462) of increasing the self-polishing properties of the paint.

Among the fouling organisms, barnacles have proved to be the most troublesome, because they are resistant to most biocides. As such, coating composition of the present invention may also include at least an effective amount of at least one specific bamaclecide, such as cuprous oxide or thiocyanate. A preferred bamaclecide is disclosed in European Patent Application Publication No. EP-A-831134, which discloses the use of from 0.5 wt% to 9.9 wt%, based on the total weight of the dry mass of the composition, of at least one 2-trihalogenomethyl-3-halogeno-4-cyano pyrrole derivative substituted in position 5 and optionally in position 1, the halogens in positions 2 and 3 being independently selected from the group consisting of fluorine, chlorine and bromine, the substituent in position 5 being selected from the group consisting of CI -8 alkyl, CI -8 monohalogenoalkyl, C5-6 cycloalkyl, C5-6 monohalogenocycloalkyl, benzyl, phenyl, mono- and di-halogenobenzyl, mono- and di-halogenophenyl, mono- and di-Cl-4-alkyl benzyl, mono- and di-Cl-4- alkyl phenyl, monohalogeno mono-Cl-4-alkyl benzyl and monohalogeno mono-Cl-4- alkyl phenyl, any halogen on the substituent in position 5 being selected from the group consisting of chlorine and bromine, the optional substituent in position 1 being selected from CI -4 alkyl and CI -4 alkoxy CI -4 alkyl.

An alternative bamaclecide is Medetomidine (commercial name Selektope) which has the chemical name 4-[l-(2,3-dimethylphenyl)ethyl]lH-imidazole (cas no. 86347-14- 0). Medetomidine may be present in the range of 0.05 wt% - 0.5 wt%.

One or more antifoulants selected from the above antifoulants may be employed in coating compositions of the present invention. The antifoulants are used in such an amount that the proportion thereof in the solid contents of the coating composition is usually from 0.05% to 90% by weight, from 0.05%> to 80%> by weight, preferably from 0.5%) to 60%> by weight, more preferably from 0.5%> to 25%> by weight, and even more preferably 0.5% to 5% by weight. Too little antifoulant does not produce an antifouling effect, while too much antifoulant results in the formation of a coating film which is apt to develop defects such as cracking and peeling and thus becomes less effective in its antifouling property.

Plasticizer, which may be included in coating compositions of the present invention, , includes, for example, phthalate-based plasticizers such as dioctyl phthalate, dimethyl phthalate, dicyclohexyl phthalate; aliphatic dibasic ester-based plasticizers such as diisobutyl adipate, dibutyl sebacate; glycol ester-based plasticizers such as diethylene glycol dibenzoate, pentaerythritol alkyl ester; phosphate-based plasticizers such as tricresyl phosphate, trichloroethyl phosphate; epoxy-based plasticizers such as epoxylated soybean oil, octyl epoxy stearate; organic tin-based plasticizers such as dioctyltin laurate, dibutyltin laurate; and trioctyl trimellitate, triacetylene.

Pigment, which may be included in coating compositions of the present invention, such as in coatings or coating compositions according to the fourth aspect of the invention, includes, for example, extender pigments such as precipitated barium sulphate, talc, clay, chalk, silica white, alumina white, bentonite; and colour pigments such as titanium oxide, zirconium oxide, basic lead sulfate, tin oxide, carbon black, graphite, red iron oxide, chromium yellow, phthalocyanine green, phthalocyanine blue, quinacridone.

Besides those described above, other additives are not particularly limited, and include, for example, rosin, organic monobasic acids such as monobutyl phthalate and monooctyl succinate, camphor, castor oil. The coating compositions of the present invention can be prepared, for example, by adding conventional additives such as other binder resins, one or more antifouling agents, a plasticizer, a coating-abrasion regulator, a pigment, and/or a solvent to the block copolymer of the present invention, and then mixing them by a mixer such as a ball mill, a pebble mill, a roll mill, a sand grind mill.

A cured or dry coating film can be formed by applying the antifouling coating composition described above in a usual manner onto the surface of a substrate to be coated and then removing the solvent through evaporation at ordinary temperature or under heating. The coating composition of the present invention can be applied to the substrate by any conventional coating technique such as brushing, spraying, dipping or flowing, but spray applications are preferred. Any of the known spraying techniques may be employed such as compressed air spraying, electrostatic spraying and either manual or automatic methods. The coating composition of the invention may be applied directly to the substrate. Typically, however, it is applied to a primer or build coat already on the substrate such that it forms an outer layer of the coated substrate and is thereby exposed directly to the marine and/or other fouling environment. One or more coatings of the composition may be applied. Accordingly, the invention extends to a substrate, preferably a metal, more preferably, a steel substrate such as an underwater structure (e.g., a ship's hull or a dock) coated with an antifouling coating composition according to the present invention. The invention also extends to a fixed, idle or mobile marine structure as described above (e.g., a dock or a ship) fully or partially coated with an antifouling coating composition according to the present invention.

In the present invention, the term coat or coating indicates a coat derived from one or more applied layers of the coating compositions described herein. The total dry film thickness of the coat may depend on the substrate, and may be 50-600μιη, more typically 75-450μιη, most typically 150-300μιη.

Features and embodiments of each aspect or exemplary embodiment of the invention are to be treated and understood as features and embodiments of each and every other aspect or exemplary embodiment of the invention, and so are to be considered as disclosed herein in the context of each aspect or exemplary embodiment unless otherwise stated or unless mutually exclusive.

For a better understanding of the invention, and to show how exemplary embodiments of the same may be carried into effect, reference will be made, by way of example only, to the accompanying illustrative examples. EXAMPLES

Methods:

The absolute number-average molecular weight (M_n) and polydispersity index (PDI) were determined by TD-SEC (size exclusion chromatography with triple detection).

For surface coating, the polymer resin was dissolved in xylene at a solid content of 40 to 50% by weight. The polymer solutions were then applied with a 300μι ^Γ coater on sand-blasted PVC panels previously washed with soap and rinsed with water and ethanol.

Contact angle measurements were performed with a Digidrop apparatus (GBX) equipped with a syringe and a flat-tipped needle, by placing ^L-droplets of deionized water (9_W) on the coated surface. The reported contact angles values are an average of five measurements on different regions of the same sample.

The antifouling activity was tested by applying the prepared paints to a panel, either directly to the panel or over a primer, mounting the panel on a frame, and immersing the frame from a raft in a seawater estuary off the Southern Netherlands during the active season (March to October). Each test also included uncoated panels and primer coated panels, both of which became heavily fouled with seaweed and some animal life within 4 weeks. Total fouling score (N) is calculated as the sum of the intensity factor (I) multiplied by the type of fouling (G = gravity factor):

N=∑(I*G)

Where the intensity factor is defined as listed in Table 1 and the gravity factor is defined as listed in Table 2.

Table 1 - Intensity Factors

Table 2 - Gravity Factors

Materials:

Methyl methacrylate (MMA) purchased from Acros, and bis(trimethylsiloxy) methylsilyl methacrylate (MATM2) supplied by Momentive Performance Materials were distilled under reduced pressure, and stored under argon before use. Other materials are obtainable from Sigma- Aldrich materials. Example A

Synthesis of a block copolymer according to an exemplary embodiment of the invention using an ARGET ATRP process.

Synthesis procedure:

An initial reaction mix was formed by charging toluene, ethyl 2-bromoisobutyrate, and copper(II) bromide EH₆-TREN solution into a flask and degassing for 20 minutes at room temperature (25°C) with nitrogen sparge (Charge 1 - initial reaction mix).

Methyl methacrylate (MMA) and tin (II) ethylhexanoate were blended together and degassed with nitrogen sparge (Charge 2).

Charge 1 was held at 90°C and Charge 2 added over 30 minutes to form the second reaction mix, which was held at 90°C for 2.5 hours. MATM2 and tin (II) ethylhexanoate were blended together and degassed with nitrogen sparge (Charge 3). Charge 3 was then added to the second reaction mix over 30 minutes at 90°C, and held at 90°C for 7 hours (final reaction mix). The proportions of additive relative to the final reaction mix (by weight) are listed in Table 3. The resulting product was formed at high conversion with 47.6% by weight present in the toluene solvent after reaction.

Table 3

The solvent was removed by evaporation and the resulting solid was found to be a clean, film-forming resin with no need for further purification or for copper removal by acetic acid treatment. The resulting diblock polymer had a composition of 50% by weight MATM2 and 50% by weight MMA with Mn measured as 25,557 g/mole (Dalton) and Mw 67,151 g/mole (Dalton).

A film formed from the resin exhibited a water contact angle of 99° initially, falling to 45° after 10 days immersion in water.

Example B

A second block copolymer was synthesised as above (i.e. as Example A) using 57 wt% block A (MATM2) and 43 wt% block B (MMA).

Comparative Example C

A comparative diblock copolymer of pMATM2-b-pMMA was synthesized using a RAFT ATRP process and an azo-containing catalyst. The production costs and times for prior art RAFT ATRP processes were frequently excessive, due largely in part to expenses related to the catalysts, typically azo compounds and organic peroxides, and synthesis methods which required days to produce the polymeric binder. Block A - MATM2 was first polymerized with 2-cyanoprop-2-yl-dithiobenzoate (CPDB) as a chain transfer agent, and block B - MMA was added to the reaction mixture in order to polymerize MMA on the chains of the pMATM2 first block.

Specifically, into a 250 ml round-bottomed flask equipped with a magnetic stir bar, MATM2 (57 wt%), CPDB, and azobis-isobutyronitrile (AIBN) were dissolved in distilled xylene, and degassed through bubbling with argon, sealed, and placed in an oil bath previously heated to 70°C until a total monomer conversion (>96%; >24 hours). When the polymerization was achieved, a solution of MMA (43 wt%) and AIBN in distilled xylene, previously degassed, was added to the reaction mixture. The polymerization was conducted until no evolution of the monomer conversion (about >24 hours). The polymer was precipitated into methanol, filtered and dried under vacuum for 48h at room temperature for further characterizing its absolute number average molecular weight (M_n=19,400g/mol).

Comparative Example D

A random (statistical) polymer was generated by charging a 250 ml round-bottomed flask equipped with a magnetic stir bar with MATM2 (57 wt%), MMA (43 wt%), CPDB, and AIBN. These components were dissolved in distilled xylene and degassed through bubbling with argon, sealed, and placed in an oil bath previously heated at 70°C until no evolution of the monomer conversion (24 hours). The polymer was precipitated into methanol, filtered and dried under vacuum for 48h at room temperature for further characterizing its absolute number average molecular weight (Mn = 18,100g/mol).

Table 4

The results presented in Table 4 show the greatly improved synthesis times for the inventive examples (A and B) produced using the chelated copper halide catalyst and the ARGET ATRP process of the present invention. Comparative Example C, which used an azo-containing catalyst and a RAFT ATRP process to produce a similar block copolymer, demonstrated much longer synthesis times (>48 hours).

The contact angle was measured for each of the binders as described in the methods section above. Each of the binders produced a surface coating having a water contact angle greater than 90°, indicating surfaces having very low surface energies. As an additional comparative example, Intersleek® 700, a commercially available fouling release coating from AkzoNobel, was coated on a surface and the contact angle was measured as 105.5° (not shown in Table 4).

After immersion in sea water, however, the ARGET polymer of Example A showed a contact angle of 45°, demonstrating that the surface becomes more hydrophilic in nature, and thus a surface which is less likely to become fouled by marine organisms. That is, hydrophilic coatings may become hydrated by the surrounding water and physically prevent adsorption of fouling organisms onto the surface, thus reducing fouling.

The contact angle of the commercially available fouling release coating Intersleek® 700 did not change upon immersion, however, indicating that the coating remains hydrophobic even when in use on a marine vessel. The "non-stick" nature of this fouling release coating may be undesirable in certain ship building environments because the coating may contaminate surrounding coating areas and cause delamination or reduced adhesion of other types of coatings such as primers, build coats, and top coats. "Surface energy", as used herein, generally refers to the ability of a surface to be freely wetted by a liquid, and concerns the liquid- so lid surface interface where wetting of the surface occurs. A surface is wettable (hydrophilic) if a liquid's molecules are more strongly attracted to the molecules of the solid surface than to each other, i.e. the adhesive forces are stronger than the cohesive forces. By contrast, a surface is not wettable (hydrophobic) if the liquid's molecules are more strongly attracted to each other than to the molecules of the solid surface, i.e. the cohesive forces are stronger than the adhesive forces. Surface energy can be quantified by measuring the contact angle of a drop of liquid placed on the surface. A contact angle less than 90° indicates at least a partial wettability of the surface, a contact angle of 0° indicates complete wetting of the surface, and a contact angle exceeding 90° indicates only little wetting, if any, of the surface.

Coating Examples

Coatings comprising block copolymers according to exemplary embodiments of the invention (Examples A and B) and comprising a comparative block copolymer (Comparative Examples C) were prepared and compared to coatings comprising statistical (random) polymers (Comparative Example D).

The proportions of additives relative to the final reaction mix for a coating composition comprising the block copolymer binder of Example A are shown in Table 5 (below).

Table 5

¹ see notes in Table 6 below The proportions of additives relative to the final reaction mix, by weight, for coating composition comprising the block copolymer binders of Examples A and B, as well as Comparative Examples C and D, are shown in Table 6 (below).

Table 6

Paint ingredient: Ti0₂ (pigment); Cuprous oxide, Econea®, Sea-nine™ (biocides); ZnO, Talc, CaC0₃ (fillers); Aerosil® 200, Disperbyk® 180 (additives); Xylene (solvent).

¹ Metal-free biocide available from Janssen

2 Biocide, DCOIT (provided as Sea-nine™; a 3 lwt% DCOIT solution in xylene), available from Dow

³ hydrophilic fumed silica additive

⁴ high molecular weight wetting and dispersing additive

⁵ percent includes xylene from binder and Sea-nine™ Each coating was evaluated for antifouling activity as defined above, and a fouling score was calculated for each (Table 7)

Table 7

¹ after seven (7) months immersion (sample size=7)

² untreated PVC panel

The results in Table 7 demonstrate that the inventive binders produced in Examples A and B form coating compositions having excellent anti-fouling activity (Inventive Examples 1 - 4). When compared to coatings comprising the binders produced in Comparative Example C, which used the expensive azo-containing catalysts (AIBN) in a RAFT ATRP process, the anti-fouling activity is similar. When compared to coatings comprising the statistical polymer binders (random copolymers) produced in Comparative Example D, the anti-fouling activity was much better. Thus, the controlled radial polymerization process using the inventive chelated copper halide catalysts of the present invention produces a block copolymer more economically (less expensive catalyst), and more quickly (9 hours versus >48hours), than binders disclosed in the prior art. Additionally, the coatings produced using these inventive binders demonstrate excellent anti-fouling activity.

Although a few exemplary embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims. For example, a different ligand may be employed as chelating agent for the catalyst.

In summary, a process for producing a block copolymer binder (A and B blocks) involves sequentially polymerizing the monomer units of one of block A or of block B and polymerizing the monomers of the other block bonded to the first polymer block. The polymerization of each polymer block may be carried out by controlled radical polymerization techniques using a chelated copper halide catalyst. The controlled radial polymerization technique may be an atom transfer radical polymerization (ATRP) process, preferably an ARGET (activators regenerated by electron transfer) polymerization process.

The monomer units in block A may be monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic and/or phosphonic acids, wherein some of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group.

Optionally, the process may include an initial reaction mix which comprises, in a solvent, a functional initiator and a catalyst chelated by a ligand; and/or wherein step (i) comprises adding monomers of the first polymer block and a first reducing agent to the initial reaction mixture to form a second reaction mix, and wherein step (ii) comprises adding monomers of the second polymer block and a second reducing agent to the second reaction mixture, after the first block copolymer has formed, to form a final reaction mix. Optionally, the catalyst may be a chelated copper halide, wherein the halide is preferably bromide; and/or the final reaction mix may comprise from lppm to lOOppm by weight of a chelated copper halide; and/or the chelated copper halide may have, as chelating agent, a ligand selected from Me₆TREN, EH₆TREN, PMDETA, TPMA, and dNbpy, or mixtures thereof, preferably EH₆TREN.

Optionally, the functional initiator may be an organic halide, preferably an alkyl bromide, preferably present at from 0.1% to 5% by weight of the final reaction mix.

Optionally, the first and second reducing agents may be independently selected from tin (II) 2-ethylhexanoate, glucose, ascorbic acid, hydrazine, and phenyl hydrazine; and/or the first and second reducing agents may be the same reducing agent, optionally both tin (II) 2-ethylhexanoate; optionally at from 1% to 15% by weight of the final reaction mix. Optionally, the first polymer block may be block A; or the first polymer block may be block B.

Optionally, at least 50% of the monomer units in block B may be monomer units (b), other than monomer residues (a).

Optionally, the monomer residues (a) of polymer block A include acrylic, (Cl-Cs alk) acrylic, itaconic, maleic, fumaric or crotonic acid, or the sulfonic or phosphonic acid equivalents thereof, with a silyl ester group containing at least 3 silicon atoms; and/or wherein the silyl group is represented by formula (I):

-(SiCR^-O Si-CR^R³) (I) wherein each R⁴ and R⁵ is independently selected from -0-SiR¹R²R³, or -O- (SiR o SiR^R³, or is hydrogen or hydro xyl, or is independently selected from a C1-C20 hydrocarbyl radical, and R¹, R² and R³ each independently represent hydrogen, hydroxyl, or are independently selected from a C1-C20 hydrocarbyl radical, and preferably, when R⁴ or R⁵ is the radical -0-(SiR⁴R⁵0)_n-SiR¹R²R³, R⁴ and R⁵ within that radical are not themselves -0-(SiR⁴R⁵0)_n-SiR¹R²R³, wherein each n independently represents a number of -Si(R⁴)(R⁵)-0- units from 1 to 1000 with the proviso that, when no R⁴ and R⁵ group present in the silyl group includes a silicon atom, n is at least 2.

Optionally, the monomer residues (a) may be derived from monomers of the following chemical formula: bis(trimethylsiloxy)methylsilylmethacrylate, MATM2; and/or trimethylsiloxy bis(dimethylsiloxy) methacrylate, MADM3.

Optionally, the monomer units (b) may be derived from momomers polymerizable or copolymerizable to form polyesters, polyurethanes, polyethers, polyacrylics, polyvinyls, polyepoxides, polyamides, polyureas, and copolymers thereof; and/or the monomer units (b) may be methylmethacrylate units.

The above described process may be used to produce a block copolymer binder comprising 50 ppm by weight or less of copper, preferably 30 ppm by weight or less of copper. The process allows controlled synthesis of the binder and removes the need for further, potentially damaging, purification of the binder to remove metal catalysts prior to use.

Also included is a block copolymer binder comprising at least two different polymer blocks A and B, wherein at least 50% of the monomer units in block A are monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic or phosphonic acids, and wherein the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group, wherein the block copolymer binder comprises 50 ppm by weight or less of copper, preferably 30 ppm by weight or less of copper. Optionally, the binder is in a solid form and which has not been subjected to reaction with acid following polymerization; and/or the binder may be further modified by chemical modification selected from esterification, hydrogenation, hydrolysis, quaternization sulfonation, hydroboration, oxidation, epoxidation, chloro/bromomethylation and hydrosilylation.

The resulting block copolymer binder may be used to form marine antifouling compositions, optionally comprising an antifouling-effective amount of at least one biocide.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Where a feature of the invention and/or step of any method or process of the invention is optional herein it should be assumed that it may be combined with any one or more aspects of the invention detailed herein either alone or in combination with any one or more other optional feature(s) and/or step(s) herein except combinations where at least some of such features and/or steps are mutually exclusive. The combinations set out in the claims are those particularly preferred. The optional features for each exemplary embodiment of the invention, as set out herein are also applicable to any other aspects or exemplary embodiments of the invention, where appropriate.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A process for producing a block copolymer binder comprising at least two different polymer blocks A and B, wherein at least 50% of the monomer units in block A are monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic and/or phosphonic acids, and wherein the monomer residues or at least some of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group; the process comprising sequentially: i) polymerizing the monomers of one of block A or block B to produce a first polymer block; and ii) polymerizing the monomers of the other of block A or block B in the presence of the first polymer block to produce a second polymer block bonded to the first polymer block; wherein the polymerization of each polymer block is carried out by controlled radical polymerization techniques, preferably an atom transfer radical polymerization (ATRP) process.

2. A process according to Claim 1, wherein the ATRP process is an ARGET (activators regenerated by electron transfer) polymerization process.

3. A process according to Claim 2, wherein an initial reaction mix for the ARGET process comprises, in a solvent, a functional initiator and a catalyst chelated by a ligand.

4. A process according to Claim 3, wherein step (i) comprises adding monomers of the first polymer block and a first reducing agent to the initial reaction mixture to form a second reaction mix, and wherein step (ii) comprises adding monomers of the second polymer block and a second reducing agent to the second reaction mixture, after the first block copolymer has formed, to form a final reaction mix.

5. A process according to Claim 3 or Claim 4, wherein the catalyst is a chelated copper halide, wherein the halide is preferably bromide.

6. A process according to Claim 5, wherein the final reaction mix comprises from lppm to lOOppm by weight of the chelated copper halide.

7. A process according to Claim 5 or Claim 6, wherein the chelated copper halide has, as chelating agent, a ligand selected from Me₆TREN, EH₆TREN, PMDETA, TPMA, and dNbpy, or mixtures thereof, preferably EH₆TREN.

8. A process according to any one of Claims 3 to 7, wherein the functional initiator is an organic halide, preferably an alkyl bromide, preferably present at from 0.1% to 5% by weight of the final reaction mix.

9. A process according to any one of Claims 4 to 8, wherein the first and second reducing agents are independently selected from tin (II) 2-ethylhexanoate, glucose, ascorbic acid, hydrazine, and phenyl hydrazine.

10. A process according to Claim 8, wherein the first and second reducing agents are the same reducing agent, optionally both tin (II) 2-ethylhexanoate, optionally at from 1% to 15% by weight of the final reaction mix.

11. A process according to any preceding Claim, wherein at least 50% of the monomer units in block B are monomer units (b), other than monomer residues (a).

12. A process according to any preceding Claim, wherein the monomer residues (a) of polymer block A include acrylic, (Cl-Cs alk) acrylic, itaconic, maleic, fumaric and/or crotonic acid, or the sulfonic and/or phosphonic acid equivalents thereof, with a silyl ester group containing 3 or more silicon atoms.

13. A process according to any preceding Claim, wherein the silyl groups or at least some of the silyl groups are represented by formula (I):

-(SiCR^-O Si-CR^R³) (I)

wherein each R⁴ and R⁵ is independently -O-SiR^R³, or -0-(SiR⁴R⁵0)_n-SiR¹R²R³, or is hydrogen or hydroxyl, or is independently selected from a C₁-C₂₀ hydrocarbyl radical, and R¹, R² and R³ each independently represent hydrogen, hydroxyl, or are independently a C₁-C₂₀ hydrocarbyl radical, and preferably, when R⁴ or R⁵ is the radical -0-(SiR⁴R⁵0)_n-SiR¹R²R³, R⁴ and R⁵ within that radical are not themselves -0-(SiR⁴R⁵0)„-SiR¹R²R³, wherein each n independently represents a number of -Si(R⁴)(R⁵)-0- units from 1 to 1000 with the proviso that, when no R⁴ and R⁵ group present in the silyl group includes a silicon atom, n is at least 2.

14. A process according to any preceding Claim, wherein the monomer residues (a) are derived from monomers of the following chemical formula:

bis(trimethylsiloxy)methylsilylmethacrylate (MATM2).

15. A process according to any preceding Claim, wherein the monomer residues (a) are derived from monomers of the following chemical formula:

trimethylsiloxy bis(dimethylsiloxy) methacrylate (MADM3).

16. A process according to any one of Claims 11 to 15, wherein the monomer units (b) are derived from momomers polymerizable or copolymerizable to form polyesters, polyurethanes, polyethers, polyacrylics, polyvinyls, polyepoxides, polyamides, polyureas, and copolymers thereof.

17. A process according to any one of Claims 11 to 16, wherein the monomer units (b) in block B are methylmethacrylate units.

18. A process for producing a block copolymer binder comprising at least two different polymer blocks A and B, the process comprising sequentially: i) polymerizing the monomers of one of block A or block B to produce a first polymer block; and ii) polymerizing the monomers of the other of block A or block B in the presence of the first polymer block to produce a second polymer block bonded to the first polymer block; wherein the polymerization of each polymer block is carried out by controlled radical polymerization techniques using a chelated copper halide catalyst.

19. A process according to Claim 18, wherein the chelated copper halide has, as chelating agent, a ligand selected from Me₆TREN, EH₆TREN, PMDETA, TPMA, and dNbpy, or mixtures thereof, preferably EH₆TREN; and the halide is preferably bromide.

20. A process according to Claim 18 or 19, wherein the controlled radical polymerization technique is an atom transfer radical polymerization (ATRP) process, preferably an activators regenerated by electron transfer polymerization (ARGET) process.

21. A process according to Claim 20 wherein an initial reaction mix for the ARGET process comprises, in a solvent, a functional initiator and the chelated copper halide catalyst.

22. A process according to Claim 21, wherein step (i) comprises adding monomers of the first polymer block and a first reducing agent to the initial reaction mixture to form a second reaction mix, and wherein step (ii) comprises adding monomers of the second polymer block and a second reducing agent to the second reaction mixture, after the first block copolymer has formed, to form a final reaction mix.

23. A process according to Claim 22, wherein the final reaction mix comprises from lppm to lOOppm by weight of the chelated copper halide.

24. A process according to any of Claims 18 to 23, wherein at least 50% of the monomer units in block A are monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic and/or phosphonic acids, and wherein at least some of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group.

25. A process according to any of Claims 18 to 24, wherein at least 50% of the monomer units in block B are monomer units (b), other than monomer residues (a).

26. A block copolymer binder obtained or obtainable by a process according to any one of Claims 1 to 25.

27. A block copolymer binder according to Claim 26, comprising 50 ppm by weight or less of copper, preferably 30 ppm by weight or less of copper.

28. A block copolymer binder comprising at least two different polymer blocks A and B, wherein at least 50% of the monomer units in block A are monomer residues (a) of ethylenically unsaturated carboxylic, sulfonic and/or phosphonic acids, and wherein the monomer residues or at least some of the monomer residues have silyl ester side groups containing at least 3 silicon atoms in the silyl group, wherein the block copolymer binder comprises 50 ppm by weight or less of copper, preferably 30 ppm by weight or less of copper.

29. A block copolymer binder according to any one of Claims 26 to 28, which is in a solid form and which has not been subjected to reaction with acid following polymerization.

30. A block copolymer binder according to any one of Claims 26 to 29, further modified by chemical modification selected from esterification, hydrogenation, hydrolysis, quaternization sulfo nation, hydroboration, oxidation, epoxidation, chloro/bromomethylation and hydrosilylation.

31. A coating composition comprising a block copolymer binder according to any one of Claims 26 to 30, and optionally an antifouling-effective amount of at least one biocide.

32. A coating composition according to Claim 31, comprising 50 ppm by weight or less of copper, preferably 30 ppm by weight or less of copper.

33. A substrate coated with a coating of an antifouling coating composition according to Claim 31 or Claim 32.