GB2530071A

GB2530071A - Antifouling Composition

Info

Publication number: GB2530071A
Application number: GB1416128.5A
Authority: GB
Inventors: Richard John Foster
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-09-12
Filing date: 2014-09-12
Publication date: 2016-03-16
Anticipated expiration: 2034-09-12
Also published as: GB201416128D0; WO2016038363A1; GB2530071B

Abstract

An antifouling composition is provided, the composition comprising a copper antifouling agent and a resin binder matrix comprising a hydrophilic resin component and a hydrophobic resin component. A composition for applying to a surface to provide an antifouling coating thereon is also provided. The composition comprises a resin composition comprising a copper antifouling agent, a hydrophilic resin precursor, a hydrophobic resin precursor and a hardener composition. The resin composition and the hardener composition are combined in use such that the hydrophobic resin precursor and the hydrophilic resin precursor react with the hardener composition to form a resin matrix containing the copper antifouling agent. A method of preparing an antifouling coating containing a copper antifouling agent comprises determining the leaching rate of copper antifouling agent required for the coating, providing a mixture comprising the copper antifouling agent, a hydrophobic resin component and a hydrophilic resin component, the ratio of the hydrophobic resin component and the hydrophilic resin component being selected to achieve the determined leaching rate and curing the mixture.

Description

ANTIFOULING COMPOSITION

The present invention relates to an antifouling composition, in particular to an antifouling composition comprising copper as an antifouling agent. The composition finds use in situations where fouling is to be prevented, in particular in the protection against fouling of marine and water-borne craft.

Copper is known to be toxic to marine plants and animals and has been employed for a considerable time as an antifouling agent. It is known to sheath articles or structures in environments that render them susceptible to fouling in copper or an alloy of copper. In the past, copper 1 oxide, often referred to as red copper oxide, has been used in paints and coatings to prevent fouling. More recently, coatings have been formed using a composition comprising metallic copper powder suspended in a carrier, such as a resin. Compositions of this latter type have gained popularity due to their ability to provide protection for extended periods of time, in some cases up to and exceeding ten years. Compositions comprising metallic copper suspended in a carrier may be applied to a surface as a coating, for example to the hull of a boat or ship. Alternatively, or in addition, the composition may be incorporated into the hull composition, for example during moulding.

US 3,219,505 concerns a treatment of surfaces to prevent fouling, the treatment comprising applying to the surface a water impermeable, thermosetting resin containing particles of copper. The resin is lightly sanded after application to the surface, in order to expose copper at the surface of the resin. The surface being treated may be coated with a glass fibre cloth prior to application of the copper/resin composition. The copper/resin composition may also be used in the manufacture of an article by impregnating a glass fibre cloth with the aforementioned copper/resin composition. The treatment is particularly suited for the hulls of boats and other articles that are immersed in water when in use.

More recently, GB 2084488 proposes a method of moulding an article to be protected from fouling, the method comprising applying to the surface of a mould a composition comprising a powder of copper or a copper alloy and a catalysed fluid resin. A layer of glass fibres and resins is applied to the composition. After curing, the moulding is removed from the mould. The surface of the resin is lightly abraded to reveal the copper or copper alloy at the surface. In addition, GB 2084488

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discloses a coating to treating a structure to prevent biofouling, the coating comprising the aforementioned copper or copper alloy/resin mixture.

ER 0 046 354 discloses a development of the coating of GB 2084488.

ER 0 046 354 discloses that resin-based compositions containing powdered copper or copper alloy may be formed from polyester and similarly curable resins providing that the resin has an acid value below about 10mg KCH/g, more preferably less than mg KOH/g. The resins employed in ER 0 046 354 are those cured by free-radical initiated cross-linking mechanisms, such as polyesters, vinyl esters and urethane acrylates. Abrasion of the surface of the composition once applied is generally required. To avoid the need to abrade the surface of the composition to expose copper, it is necessary to employ high loadings of copper or copper alloy in the composition.

Compositions according to the disclosure of GB 2084488 and ER 0 046 354 found a measure of commercial success, in particular for use as a gel coat in the manufacture of a moulded boat hull, prior to the hull being laminated. However, the need to abrade the coating to reveal the copper at the surface of the coating is not practical and leads to technical problems. The use of high copper loadings to avoid the need to abrade the surface is not practical.

More recently still, an epoxy resin-based antifouling composition was developed and commercialised. The composition was intended to avoid the need to abrade the surface in order to reveal copper. The composition comprised copper powder bound in an epoxy resin matrix. The resin matrix included a water soluble resin, such as an ethylene vinyl alcohol resin or the like, with the intention that the water soluble resin would dissolve in use, leaving the epoxy resin matrix porous, allowing the copper to leach to the surface. Products employing this composition have been made commercially available under the trade names CoppercoatTM and Copper 20001M The principle of rendering an epoxy-based copper antifouling composition porous to water has been successfully developed and commercialised in the current commercial product CopperplusTM. The product comprises copper dispersed in an epoxy resin matrix. The resin matrix is rendered porous by the inclusion of methyl diproxitol, which leaches out of the matrix over time, exposing the dispersed copper.

Epoxy resin is a good binder for coating compositions. However, epoxy resin is virtually impermeable to water. Modification of the epoxy resin matrix is therefore required in order to achieve the porosity necessary to allow the composition to be effective as an antifouling treatment, if abrasion of the surface of the composition to reveal the copper antifouling agent is to be avoided. The permeability of modified epoxy resin binders is affected by the degree of cure of the binder. This is in turn affected by the ambient temperature at the time the resin composition is applied as a coating. The permeability is also affected by temperature over time, for a month or more after application.

Other factors that affect the performance of an epoxy-based copper antifouling composition are the ratio of hardener to resin employed. In addition, over the lifetime of the coating, unreacted epoxy groups in the matrix can homopolymerise, which in turn can reduce the permeability of the resin matrix with a consequent reduction in the antifouling performance.

There is a need to improve the reliability and performance of copper-based antifouling compositions. In particular, it would be advantageous if the performance of the composition could be improved, to avoid the need to reapply the composition to the treated surface. Any improved composition should preferably avoid the need to abrade the surface to reveal the copper active component.

Surprisingly, it has been found that an improved antifouling composition is provided when copper powder is dispersed in a resin matrix comprising a hydrophilic resin component and a compatible hydrophobic resin component.

Accordingly, in a first aspect, the present invention provides an antifouling composition comprising: a copper antifouling agent; and a resin binder matrix comprising a hydrophilic resin component and a hydrophobic resin component.

The composition comprises a powdered copper antifouling agent dispersed in a resin binder system. The resin binder matrix comprises a hydrophilic resin component and a hydrophobic resin component. It has been found that the composition of the present invention exhibits improved antifouling performance. In particular, the composition exhibits a leaching rate of copper that is controllable and is unaffected by the ambient conditions both during and after the application of the composition.

The presence in the resin binder matrix of a hydrophilic resin component renders the resin binder system permeable. This in turn allows the composition to absorb water, thus allowing copper ions to diffuse to the surface of the coating, without the need to abrade the composition once applied. It has been found that the leaching rate of copper from the composition is readily controlled by varying the proportions of the hydrophilic and hydrophobic components of the resin binder matrix.

The composition comprises a copper antifouling agent. The presence of copper in the composition provides the required antifouling activity. Copper may be present in the composition in any suitable form that provides an antifouling action at the surface of the composition when applied. In particular, the antifouling action is provided by the presence of copper ions at the surface of the composition, which are oxidised to form copper 1 oxide, which is the active agent in preventing fouling.

Accordingly, the copper antifouling agent present in the composition may be any copper-containing compound or composition that is able to generate copper ions upon contact with water.

The copper antifouling agent is most preferably present in a finely divided form, in particular as a powder, more particularly as a spherical powder.

In a preferred embodiment, the copper antifouling agent comprises copper metal. Alternatively or in addition, the copper antifouling agent may comprise a copper alloy that exhibits an antifouling activity. Examples of such antifouling, copper-containing alloys include alloys of copper and nickel, such as copper/nickel alloys having a ratio of copper and nickel of from 90:10 to 99:1 parts by weight. A copper/nickel alloy having a ratio of copper and nickel of 90:10 is effective as an antifouling agent and exhibits a low leaching rate for the copper. As a further alternative, the copper antifouling agent may comprise a copper-containing compound, for example copper 1 oxide.

The copper antifouling agent may be present in the antifouling composition in any suitable amount, in particular to provide the required antifouling protection when the composition is applied to a surface to be protected. The composition may

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comprise at least 30% by weight of the copper antifouling agent, preferably at least 40%, more preferably at least 50%, still more preferably at least 60% by weight. The copper antifouling agent may be present in the composition in an amount of up to 90% by weight, more preferably up to 80% by weight, still more preferably up to 70% by weight. An amount of the copper antifouling agent in the range of from 50 to 80% by weight is preferred, more preferably in the range of from 60 to 70% by weight.

The copper antifouling agent is dispersed in the resin binder matrix. The resin binder matrix comprises a hydrophilic resin component and a hydrophobic resin component. It is preferred that the hydrophobic resin component constitutes the major portion of the resin binder matrix, with the hydrophilic resin component forming the minor component of the resin binder matrix.

As indicated above, the leaching rate of copper from the composition is dependent upon the amount of hydrophilic resin component present in the resin binder matrix, relative to the amount of hydrophobic resin component. This provides a means for accurately controlling the copper leaching rate of the composition when applied and in use. The weight ratio of the hydrophilic resin component to the hydrophobic resin component in the resin matrix is preferably at least 1:1.5, that is the resin component comprises at least 60% by weight of the hydrophobic resin.

more preferably at least 1:2, that is the resin component comprises at least 67% by weight of the hydrophobic resin, still more preferably at least 1:3, that is the resin component comprises at least 75% by weight of the hydrophobic resin. The weight ratio of the hydrophilic resin component to the hydrophobic resin component in the resin matrix may be up to 1:20, that is the resin component comprises up to 95% by weight of the hydrophobic resin, more preferably up to 1:15, that is the resin component comprises up to 94% by weight of the hydrophobic resin, still more preferably up to 1:10, that is the resin component comprises up to 91% by weight of the hydrophobic resin.

The resin binder matrix may comprise the hydrophilic resin component in an amount of up to 40% by weight, more preferably up to 30% by weight. The resin binder matrix preferably comprises at least 5% by weight of the hydrophilic resin component, more preferably at least 10%, still more preferably at least 15%. The hydrophilic resin component is preferably present in the resin binder matrix in an amount of from 5 to 35% by weight, more preferably from 10 to 30%, still more preferably from 15 to 25% by weight.

Similarly, the resin binder matrix may comprise the hydrophobic resin component in an amount of up to 60% by weight, more preferably up to 70% by weight. The resin binder matrix may comprise up to 95% by weight of the hydrophobic resin component, more preferably up to 90%, still more preferably up to 85%. The hydrophobic resin component is preferably present in the resin binder matrix in an amount of from 65 to 95% by weight, more preferably from 70 to 90% by weight, still more preferably from 75 to 85% by weight.

The hydrophobic resin component may be a hydrophobic resin or a resin monomer or precursor that can be cured to form a hydrophobic resin, for example by reaction with a hardener. Such resin systems are known in the art.

Suitable hydrophobic resin components for inclusion in the resin binder matrix are known in the art and commercially available. Suitable hydrophobic resin components are any resin components that can be used to form a resin matrix for use as a coating on a surface to be treated and protected. The hydrophobic resin component may be a thermosetting resin or a thermoplastic resin system.

Thermosetting resin systems are preferred, as they produce more durable coatings.

Suitable hydrophobic resins for forming coatings include epoxy resins. Epoxy resin systems can be formulated to include a hydrophilic component, such as a polyoxyethylene. The polyoxyethylene may be included in either the resin monomers or the hardener components. However, as the curing of the epoxy resin occurs over time, the extent and rate of curing vary according to the ambient temperature.

Accordingly, epoxy resins are not preferred for use in the composition of the present invention.

Rather, hydrophobic resins for use in the composition of the present invention are preferably those that have their extent of cure less dependent upon ambient temperature. In particular, the temperature-dependency of the resin is preferably within an acceptable range, that is the properties of the resin are not significantly varied across the range of temperatures to which the resin will be exposed during preparation of the coating and its subsequent use. Preferred hydrophobic resins are polyurethane resins, acrylic resins, polyester resins and epoxyester resins.

Polyurethane resins are particularly preferred.

In one preferred embodiment, the hydrophobic resin is a water-borne polyurethane prepared from a hardener, in particular an isocyanate and a resin, in particular a polyol. Preferably, an excess of the hardener is used, ensuring that most, if not all, of the resin reacts with the hardener, with the remaining hardener reacting with the water. In this way, further reaction of the hydrophobic resin components is prevented.

The resin binder matrix of the composition further comprises a hydrophilic resin component. The hydrophilic resin component is present in the resin matrix formed by the hydrophobic resin component. In one embodiment, the hydrophilic resin component and the hydrophobic resin component are present as a physical mixture within the matrix, for example in the form of an interpenetrating polymer network. More preferably, the hydrophobic resin component and the hydrophilic resin component are chemically linked within the resin matrix. Such a chemical linkage is preferably achieved by selecting the hydrophobic resin and the hydrophilic resin to react with the same hardener, in particular an isocyanate hardener. As noted above, when preparing the resin matrix, it is preferred to use an excess of the hardener, for example at least twice the stoichiometric amount of hardener required to react with both the hydrophobic resin and the hydrophilic resin components.

A preferred hardener for the system is one that reacts with water, in particular an isocyanate. In this way, any excess unreacted hardener reacts with water, such as moisture in the atmosphere, within a shod period of time after the coating has been applied.

Alternatively, the resin matrix may be formed by reacting each of the hydrophobic resin component and the hydrophilic resin component with a different, respective hardener. In such a case, it is still preferred that the two resin components are chemically linked within the resin matrix.

In use, the hydrophilic resin component, as a result of being chemically bound and/or physically retained within the resin binder matrix, remains in the resin binder matrix and the coating, once applied. The cured hydrophilic resin component acts to absorb water into the resin binder matrix. The water so absorbed dissolves the

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copper antifouling agent present in the composition, producing copper ions. The copper ions leach to the surface of the composition and form copper 1 oxide at the surface, which in turn acts as the active agent to prevent fouling.

The hydrophilic resin component may be a hydrophilic resin monomer. The resin monomer is cured to form the hydrophilic resin component.

Suitable monomers include acid group-containing hydrophilic unsaturated monomers and salts thereof, nonionic hydrophilic unsaturated monomers and cationic hydrophilic unsaturated monomers. Oligomers and resins formed with the aforementioned monomers may also be used as the hydrophilic resin component of the resin binder matrix of the composition.

Examples of acid group-containing hydrophilic unsaturated monomers include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, acryloyloxy propionic acid, vinyl-sulfonic acid, styrene-sulfonic acid, 2-(meth)acrylamide-2-methyl propane sulfonic acid, 2-(meth)acryloyl ethane sulfonic acid, 2-(meth)acryloyl propane sulfonic acid, and sulfoethoxy polyethylene glycol mono(meth)acrylate, and salts thereof.

Examples of nonionic hydrophilic unsaturated monomers include acrylamides, such as acrylamide, methacrylamide, N-ethyl (meth)acrylamide, N-n-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N,N-methyl (meth)acrylamide; acrylates and methacrylates, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxy polyethylene glycol (meth)acrylate, polyethylene glycol mono(meth)acrylate; pyridines, such as vinyl pyridine; piperidines, such as N-acryloyl piperidine; and pyrrolidones, such as N-acryloyl pyrrolidine.

Examples of cationic hydrophilic unsaturated monomers include certain acrylates and acrylamides, such as N,N-dimethylaminoethyl (meth)acrylate, N,N- diethylaminoethyl (meth)acrylate, N,N-dimethyl-aminopropyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide, and quaternary salts thereof.

As noted above, oligomers and resins formed with the above monomers may also be used as the hydrophilic resin component to form the resin binder matrix of the composition. In embodiments in which the composition comprises a monomer or precursor for one or both of the resin components, these are reacted and cured as described above to form the resin matrix in the final coating or layer formed using the composition.

Preferred hydrophilic components for use in the resin binder matrix of the composition are polyoxyethylene polyols and vinyl pyrrolidone. Polyoxyethylene polyols and polyoxyethylene/oxypropylene copolymer polyols are particularly preferred hydrophilic resin components for use in the composition of the present invention. Polyoxyethylene polyols are solids at room temperature, with the exception of very low molecular weight products. Copolymer polyols with ethylene oxide and propylene oxide are liquids at room temperature.

Polyoxyethylene/oxypropylene copolymer polyols having an ethylene oxide to propylene oxide (EO/PO) of 70/30 or 75/25 are particularly preferred.

The resin binder matrix comprises a hydrophobic resin component and a hydrophilic resin component. The hydrophobic resin component and the hydrophilic resin component together form the resin matrix in the cured composition, in which the copper antifouling agent is dispersed.

The hydrophilic and hydrophobic resin components are selected to be compatible with one another. Preferably, the hydrophobic resin component and the hydrophilic resin component are suitable to be cured together in a mixture, more preferably with the use of a single hardener composition, as noted above. When using a single hardener for both resin components, the hydrophilic resin may be combined with the hydrophobic resin before the hardener is added. Alternatively or in addition thereto, the hydrophilic resin component may be combined with the hardener, before being added to the hydrophobic resin for curing. It is to be noted that the hardener may be selected to impart the required hydrophilic or hydrophobic properties to one of the resin components. For example, in embodiments comprising a polyurethane resin matrix, a hydrophilic hardener may be prepared by reacting a hydrophilic component, such as a polyoxyethylene, with an isocyanate to form a hydrophilic hardener.

The hydrophilic resin component should also be compatible with the method of curing the hydrophobic resin component. In particular, the hydrophilic resin component should not interfere with the curing of the hydrophobic resin component to form the resin matrix. Further, the hydrophilic and hydrophobic properties of the resin components must be retained when the components are mixed and are cured together.

For example, in one embodiment of the composition, the hydrophobic resin component is a hydroxylated acrylic resin, preferably present in the form of an emulsion, and the hydrophilic resin component is a polyoxyethylene polyol, which when reacted form a polyurethane resin matrix. The polyurethane resin is typically formed by a reaction involving an isocyanate, preferably a water miscible isocyanate, which is used as the basis for a hardener. The polyoxyethylene polyol may be combined with the hydrophobic resin component or may be used to prepare a prepolymer with an isocyanate for use as the hardener system.

The resin binder matrix may comprise a single hydrophobic resin component or a mixture of two or more such components. Similarly, the resin binder matrix may comprise a single hydrophilic resin component or a mixture of two or more thereof.

In use, the composition of the present invention is provided as a coating or layer on the surface of an article, item or structure. In this form, the resin binder system is cured and in the form of a resin matrix having the copper antifouling agent dispersed therethrough. The composition may be applied to the surface in any suitable form to provide the aforementioned coating that is effective in preventing fouling by aquatic plants and animals.

In one embodiment, the composition of the present invention is provided as an uncured formulation, such as a paint composition. In this form, the composition comprises the resin components in the form of monomers, pre-polymers and/or precursors that are subsequently cured to form the coating as described above. The composition is preferably provided with a separate hardener composition, as is common practice in the art, such that when the two compositions are combined the resin components cure to form the aforementioned resin matrix.

Accordingly, in a further aspect, the present invention provides a composition for applying to a surface to provide an antifouling coating thereon, the composition comprising: a resin composition comprising: a copper antifouling agent; a hydrophilic resin precursor; a hydrophobic resin precursor; and a hardener composition; in use the resin composition and the hardener composition being combined.

whereby the hydrophobic resin precursor and the hydrophilic resin precursor react with the hardener composition to form a resin matrix containing the copper antifouling agent.

The components of the composition are as hereinbefore described.

As noted above, the hardener composition may comprise a hardener component for reacting with each of the hydrophobic resin precursor and the hydrophilic resin precursor. More preferably, a single hardener component for reacting with both the resin components is employed.

The hydrophilic resin precursor may be present in combination with the hydrophobic resin precursor. Alternatively, or in addition thereto, the hydrophilic resin precursor or the hydrophobic resin precursor may be present in the hardener composition.

Compositions of this embodiment may comprise one or more additional components, for example components that aid the composition being applied to the surface. Other components included in coating compositions that may be present in the composition of the present invention are known in the art.

The composition may be free of a solvent. More preferably, the composition comprises one or more solvents. Suitable solvents are known in the art and include organic solvents and water. Water is a preferred solvent, as it has a low environmental impact, has few health concerns for users and is readily available.

The solvent is present in a sufficient amount to facilitate application of the uncured composition to the surface being treated. Higher solvent amounts reduce the relative amount of copper antifouling agent in the composition, in turn making application of the composition to the surface easier.

A solvent is preferably employed for higher melting point resin components, in particular those that are solid at room or ambient temperatures.

The resin component may be dissolved in the solvent. Alternatively, and more preferably, the resin component may be dispersed in the solvent, in particular as an emulsion. For example, in one preferred embodiment, the resin binder matrix of the coating composition comprises an acrylic resin as the hydrophobic resin component. The acrylic resin is provided in the form of an emulsion of acrylic monomers in water. The emulsion is polymerised to form a dispersion of particles of solid resin in water.

Embodiments of the composition of the present invention that are intended for use as a gel coat, for example for application in a mould, are most preferably free of solvent.

The solvent is preferably present in an amount of from 0 to 60% by weight of the composition, more preferably from 1 to 50%, still more preferably from 2 to 40%, more preferably still from 5 to 30% by weight. A particularly preferred solvent content of the composition is from 10 to 25% by weight.

Other components that may be present in the composition of this embodiment are known in the art and include, for example, one or more air release agents, one or more surface wetting agents and one or more thickeners. Suitable components are commercially available.

In one preferred embodiment of the composition of the present invention, the hydrophobic resin component of the resin binder system is a polyurethane resin. The preferred hydrophilic resin component for use in a polyurethane binder system is a polyoxyethylene polyol. The permeability of a copper antifouling agent bound in a polyurethane binder system can be readily controlled by varying the amount of the polyoxyethylene polyol component in the composition.

It is well known in the polyurethane industry that unlike propylene, ethylene oxide containing polyols are water absorbing and consequently they are not normally used in the industry. However suitable polyoxyethylene polyols and polyoxyethylene/oxypropylene copolymer polyols are made in large quantities for other applications such as lubricants and, hence are readily available.

Polyoxyethylene polyols and polyoxyethylene/oxypropylene copolymer polyols are particularly preferred hydrophilic resin components for use with polyurethane resin binder systems. Polyoxyethylene polyols are solids at room temperature, with the exception of very low molecular weight products. Copolymers with propylene oxide are liquids at room temperature. Polyoxyethylene/oxypropylene copolymer polyols having an ethylene oxide to propylene oxide (EO/PO) of 70/30 or 75/25 are preferred, as noted above.

As discussed above, it has been found that the leaching rate of the copper antifouling agent from the composition when cured is controllable by varying the amount of hydrophilic resin component present in the resin binder system, that is by varying the ratio fo the hydrophobic and hydrophilic resin components.

Accordingly, in a further aspect, the present invention provides a method of preparing an antifouling coating containing a copper antifouling agent, the method comprising: determining the leaching rate of copper antifouling agent required for the coating; providing a mixture comprising the copper antifouling agent, a hydrophobic resin component and a hydrophilic resin component, the ratio of the hydrophobic resin component and the hydrophilic resin component being selected to achieve the determined leaching rate; and curing the mixture.

As discussed above, the composition of the present invention is applied to a surface to provide an antifouling coating or layer.

Accordingly, in a still further aspect, the present invention provides a method of forming an antifouling coating, the method comprising applying to a surface a composition as hereinbefore described.

The surface to which the composition is applied may be the surface of an article, such as the hull of a water borne craft or the surface of a submerged structure. Alternatively, the composition may be applied to the surface of a mould, for example to form a gel coat, as part of the moulding process for an article, such as the hull of a water borne craft.

Still further, the present invention provides an article, such as a water borne vessel, comprising an antifouling composition as hereinbefore described on at least a portion of the surface thereof.

Embodiments of the present invention will now be described, for the purposes of illustration only, by way of the following examples.

EXAMPLES

Example 1

Comparative Example

An antifouling composition comprising a hydrophobic resin component was prepared having the components set out in Table 1:

Table 1

RESIN COMPONENT Amount (Parts by weight) raldite FL 756/67 epoxy resin dispersion in water, 67%wt solids 50 Hydroplat 140 Rheology agent 0.4 Foam master 306 Air release agent 1 Surface wetting agent 0.5 ater 18.1

HARDENER COMPONENT

lncorez 148-700 Water miscible epoxy hardener 35 Polyviol polyvinyalcohol resin 25% in water 35

ANTIFOULING AGENT

Thpper powder 230 The efficacy of the antifouling composition summarised in Table 1, in terms of the rate at which copper was leached from the composition, was tested using the procedure set out in British Standard EN ISO 15181-1:2007 Parts 1 and 2. Sea water filtered through a 10 micron filter was used in place of the artificial sea water called for in the standard test procedure.

The results of the test are set out in Table 2 below.

Table 2

Time Temperature Leaching Rate (Days) (°C) (micrograms/cm2/day) 2 8 42 8 38.4 15 37.6 2 30 20.4 30 21.1 35 18.9

Example 2

A composition was prepared having the components indicated in Table 3.

Table 3

RESIN COMPONENT Amount (parts by weight) Hydroxylated acrylic dispersion (43% wt 170.83 solids) (Craymul 2171TM) Water 25.42 High ethylene oxide polyol 22.17 (Desmophen 41 WB 01TM) Air release agent (10% wt in water) 5.88 (Dow Corning Additive 621M) Surface wetting agent (10% wt in water) 1.86 (Capstone FX61TM) Polyurethane thickener (20% wt in water) 7.83 (Rheovis PU 127jTM)

HARDENER COMPONENT

Water miscible isocyanate (hardener) 24.87 (Rhodocoat XLSOOTM)

ANTIFOULING AGENT

Copper powder 513.15 The above components were mixed and formed a smooth paint. The paint exhibited superior application properties compared with known epoxy resin bound systems.

The efficacy of the antifouling composition of Table 2, in terms of the rate at which copper was leached from the composition, was tested using the procedure set out in British Standard EN ISO 15181-1:2007 Parts 1 and 2. Sea water filtered through a 10 micron filter was used in place of the artificial sea water called for in the standard test procedure.

The results of the test are set out in Table 4 below.

Table 4

Time Temperature Leaching Rate (Days) (°C) (micrograms/cm2/day) 2 8 37.2 8 38.4 15 35.1 2 30 40.2 30 39.3 35 34.9 As can be seen from Table 4, the composition of the present invention exhibited excellent leaching rates of copper from the composition. Compared with the composition of Example 1, it can be seen that the composition of the present invention, comprising both a hydrophilic resin component and a hydrophobic resin component in the resin binder matrix, exhibited superior leaching rates for the copper antifouling agent.

It was found that the leaching rate of the composition of Example 2 could be easily controlled by varying the amount of the hydrophilic resin precursor, that is the high ethylene oxide polyol, present in the composition, that is by adjusting the ratio of the hydrophilic and hydrophobic resin components. In particular, the leaching rate could be readily increased by increasing the amount of high ethylene oxide polyol present in the composition, relative to the amount of the hydroxylated acrylic component.

Claims

CLAIMS1. An antifouling composition comprising: a copper antifouling agent; and a resin binder matrix comprising a hydrophilic resin component and a hydrophobic resin component.
2. The antifouling composition according to claim 1, wherein the copper antifouling agent is a powder.
3. The antifouling composition according to claim 2, wherein the copper antifouling is a spherical powder.
4. The antifouling composition according to any preceding claim, wherein the copper antifouling agent comprises copper metal.
5. The antifouling composition according to any preceding claim, wherein the copper antifouling agent comprises an alloy of copper.
6. The antifouling composition according to claim 5, wherein the alloy of copper is a copper/nickel alloy.
7. The antifouling composition according to any preceding claim, wherein the copper antifouling agent comprises copper 1 oxide.
8. The antifouling composition according to any preceding claim, wherein the copper antifouling agent is present in an amount of from 50 to 80% by weight.
9. The antifouling composition according to any preceding claim, wherein the hydrophobic resin component comprises the major portion of the resin binder matrix.
10. The antifouling composition according to claim 9, wherein the ratio of the bydrophilic resin component to the hydrophobic resin component is at least 1:1.5.
11. The antifouling composition according to claim 10, wherein the ratio of the bydrophilic resin component to the hydrophobic resin component is at least 1:3.
12. The antifouling composition according to any of claims 9 to 11, wherein the ratio of the hydrophilic resin component to the hydrophobic resin component is no greater than 1:20.
13. The antifouling composition according to claim 12, wherein the ratio of the hydrophilic resin component to the hydrophobic resin component is no greater than 1:10.
14. The antifouling composition according to any preceding claim, wherein the hydrophobic resin component is a thermosetting resin.
15. The antifouling composition according to any preceding claim, wherein the hydrophobic resin component comprises a polyurethane resin, an acrylic resin, a polyester resin, an epoxyester resin, or a precursor thereof.
16. The antifouling composition according to claim 15, wherein the hydrophobic resin component comprises a polyurethane resin or precursor thereof.
17. The antifouling composition according to any preceding claim, wherein the hydrophobic resin component and the hydrophilic resin component are chemically linked within the resin matrix.
18. The antifouling composition according to claim 17, wherein the hydrophobic resin component and the hydrophilic resin component are cured by reaction with the same hardener.
19. The antifouling composition according to any preceding claim, wherein the bydrophilic resin component is formed from one or more acid group-containing hydrophilic unsaturated monomers and salts thereof, nonionic hydrophilic unsaturated monomers or cationic hydrophilic unsaturated monomers.
20. The antifouling composition according to any preceding claim, wherein the bydrophilic resin component is formed from one or more polyoxyethylene polyols.
21. A composition for applying to a surface to provide an antifouling coating thereon, the composition comprising: a resin composition comprising: a copper antifouling agent; a hydrophilic resin precursor; a hydrophobic resin precursor; and a hardener composition; in use the resin composition and the hardener composition being combined, whereby the hydrophobic resin precursor and the hydrophilic resin precursor react with the hardener composition to form a resin matrix containing the copper antifouling agent.
22. The antifouling composition according to claim 21, wherein the copper antifouling agent is a powder.
23. The antifouling composition according to claim 22, wherein the copper antifouling is a spherical powder.
24. The antifouling composition according to any of claims 21 to 23, wherein the copper antifouling agent comprises copper metal.
25. The antifouling composition according to any of claims 21 to 24, wherein the copper antifouling agent comprises an alloy of copper.
26. The antifouling composition according to claim 25, wherein the alloy of copper is a copper/nickel alloy.
27. The antifouling composition according to any of claims 21 to 26, wherein the copper antifouling agent comprises copper 1 oxide.
28. The antifouling composition according to any of claims 21 to 27, wherein the copper antifouling agent is present in an amount of from 50 to 80% by weight.
29. The antifouling composition according to any of claims 21 to 28, wherein the hydrophobic resin precursor comprises the major portion of the resin precursor.
30. The antifouling composition according to claim 29, wherein the ratio of the hydrophilic resin precursor to the hydrophobic resin precursor is at least 1:1.5.
31. The antifouling composition according to claim 30, wherein the ratio of the bydrophilic resin precursor to the hydrophobic resin precursor is at least 1:3.
32. The antifouling composition according to any of claims 29 to 31, wherein the ratio of the hydrophilic resin precursor to the hydrophobic resin precursor is no greater than 1:20.
33. The antifouling composition according to claim 32, wherein the ratio of the hydrophilic resin precursor to the hydrophobic resin precursor is no greater than 1:10.
34. The antifouling composition according to any of claims 21 to 33, wherein the hydrophobic resin precursor is a thermosetting resin.
35. The antifouling composition according to any of claims 21 to 34, wherein the hydrophobic resin precursor comprises a precursor for a polyurethane resin, an acrylic resin, a polyester resin, or an epoxyesler resin.
36. The antifouling composition according to claim 35, wherein the hydrophobic resin precursor comprises a precursor for a polyurethane resin.
37. The antifouling composition according to any of claims 21 to 36, wherein the hydrophobic resin precursor and the hydrophilic resin precursor react to be chemically linked within the resin matrix.
38. The antifouling composition according to claim 37, wherein the hydrophobic resin precursor and the hydrophilic resin precursor are cured by reaction with the same hardener.
39. The antifouling composition according to any of claims 21 to 38, wherein the hydrophilic resin precursor is one or more acid group-containing hydrophilic unsaturated monomers and salts thereof, nonionic hydrophilic unsaturated monomers or cationic hydrophilic unsaturated monomers.
40. The antifouling composition according to any of claims 21 to 39, wherein the hydrophilic resin precursor comprises one or more polyoxyethylene polyols.
41. The antifouling composition according to any of claims 21 to 39, wherein the hardener composition is present in excess of the amount required to react with the hydrophobic resin precursor and the hydrophilic resin precursor.
42. The antifouling composition according to any of claims 21 to 39, further comprising one or more solvents.
43. The antifouling composition according to claim 42, wherein the solvent is water.
44. The antifouling composition according to either of claims 42 or 43, wherein at least one of the resin precursors is present as an emulsion in the solvent.
45. The antifouling composition according to any of claims 42 to 44, wherein the solvent is present in the composition in an amount of from 0 to 60% by weight.
46. An antifouling composition substantially as hereinbefore described.
47. A method of preparing an antifouling coating containing a copper antifouling agent, the method comprising: determining the leaching rate of copper antifouling agent required for the coating; providing a mixture comprising the copper antifouling agent, a hydrophobic resin component and a hydrophilic resin component, the ratio of the hydrophobic resin component and the hydrophilic resin component being selected to achieve the determined leaching rate; and curing the mixture.
48. A method of forming an antifouling coating, the method comprising applying to a surface a composition according to any of claims 1 to 46.
49. An article comprising on at least a portion of the surface thereof a composition according to any of claims 1 to 46.
50. A water borne craft comprising a composition according to any of claims 1 to 46 on at least a portion of the surface thereof.
51. A method of forming an antifouling composition substantially as hereinbefore described.Amended claims have been filed as follows:-An antJfouino cornpostion comprising: a copoer antif.ounq agent: and a. en binder matrix.comp.dsing a hydrophiflc resin component and o iS rwdroohohEc resin component, wherein the hydrophobic resin component and the hvdrophihc. resin component are dhemicaliy iin.ked within the resin matrix'.2. The antifoulino connposmon according to claim I. wherein the copper antifduhng. aQent is a powder.0 3. The antitbuling comp.osidmi according to claim 2. wherein the copper antdoullng in a epheric.ai oowd.er.6. The antifoung composition according to any preceding claim, wherein the cooper antifouling agent comprises copper metal. r0 The antitouhng comros.non acccrthng to an of claims Ito 3. wherein LC) the copper antifouUng agent comprises an alloy of conner. r6. Ito;anhfouhng composition according to claim 5, wherein the alloy of copper lea copper/nickel alloy.7 The antftouling composition accordinu to any cd claims I to 2. wherein the copr.er antitbuling agent comprises copper I oxide.The a". ou rg c ocsPor ancoro og a. o eeig t't C C the copper armtbullng agent is present in an amount of from 50 to 80% by weight.9. The antifoulino composition according to any pre.cethng claim, wherein :30 the hydrophobic resin pomponent comprises the ma,or portion ct the resin bnder matrix.TO. The anthouing composition according to claim 9, herein the ratio of the hydrophiiic resin component to the hydrophobic resin component s at ii ç 1. The.antifouUnç composition 0000rthng to caim 10, wheren the ratio of the hydrophjc resin component to the hydrophobic resin component is at HI 12, The antffcwhng composition acoording to any of claims 9 HI 11, wherein the ratio of the hydrophilic res0i component to the hydrophobic resin comoonent is no greater than 120.13. The andfo.uiing composition according to ciaftr 12, wherein the atio of 15: the hydrophilic resin corn ponent to the hyarophobc resin; compc cent aco greater than 1:10., If) 1$. The antifouhng.co.mposftHIn accordion to any preceding ciaiht wherein the hydrophobic resin component is* a thermosetting resin I'S. The aiittouhn' composition according to any preceding claim,, wherein the hydrophobic resin, component comprises a polyurethane resin. an acrylic resin, a polyester resin, an epoxyester.e5n, or a precursor thereof.2.5 10. The anthouhng composition according to claim. 15, wherein the Pwdropno.b'c resin component comnrises a coivurethane resin or precursor thereof.i0t nng,,c r po c' accoc no tO an creced ç m the hydrophobic resin component and the hydrophilic resin component are cured by reaction with the same hardener.It The an cuftngccmpødkn:wtg tq any preçe*ig ctS'. wheeh the hydtbphiftc rsafrr eornpbnent Stnned fran one or more acid group-anakifng hydrophlltc unsaturated imrs*rs Øndf5Slt$ thsro& norilort hydrophilk unsaturated:r$noñiers at cifiaS hedittiIib üh PatS monrrte:.14. The anftfSiin4 npn act. dInub any of claims 1 lo tT, wherein the hydroç*1K ten ç rnponenila tanned from one or morn poiyoxyeth4ene poyeIs. El W 2Q i*,fppyi1gsurfacetopdeanfln9coating there*:, the oompo*or comprising a cesin cQmposition coprsThg a sgpe, n s I:n *ont tlydtcphiUr rA preturst, ___ IS a hydrophobIc resin eeurso and a hardener composition: in use it's reir* composition *t4 the hardener.anpasWon being: o4rnthned.wtierebythshydrophobkc resinprecursOr*ildtha bflhW *irrprecutsbt tact LI') with the hr*n tenet corrpos1tS to form:3 ret matS otó1nfrsg a hdophbtc esin 3D prnfl*rsit, a hyØrephaUc,Scnnonent arid the c*pperant%uling gent1 the hphobCto&n:pnnt. ahd the fi4drpfliWc resin camp*nent ik,kedin the: resib mthrix.21. The a touWlgtGmposWtn aecorthngto ciam 20, wher&n the copper antffbufing agent isa powder. 4"',a, Tent!otSg4c,p9s ocotdtnto fl' 21,*tit*in the copper:1 s,ntifu$is a spherSl powØetc as. the t4fouhu1 ostio hl9to nymcams2o to 22c O wher&n the oopp*radfttouling agent conpries copper meta! 4, The audfouftng compgflion according to anydciaims20'to2Z.wher&n the copper añtIf'ouling agent cøwptises an alloy of copper a The:*ntifot$ing eomposltlort aecafling to:cL&rn 24, whereIn the alloy of copper is a copperThick& alloy. :Z The:ansif!. fing:qt11pc!sUon a'xc $ina tp any of claims 20 to: 22, hra the copper aM oufln* agent comprises copper 1 xida 27. tfteaSMS1n poMfion aatd1Pg taiy of *Smn* 2Q t 2$, tip thecopper:antibuffng agent: is present in an amount of from 61) to 80% biett fl The antWóui4ng eowposttion aeordirg to ti of claithE 20 to 21, wher* the hydrophobic 16*: PYGC WSPt CoiWth,, thG Th*t pørtion of the o tesit I-1$ 20. tttanthbuUng t::posiiion ** :lng to *m 28. w$øremn the So of O the hy;rophi resin precursorto the t>*ophobinesnpreQvrsor s: at teast:1 LI') i;t5 t) 3D, TboaPtthJlm oitp*idoa øctWttg to claim 29 wøt&nths sb* The hyd:rqphuk reS prcursecto the. hydrophobicreaWtprursor ia at Ieast 31. The srtifGring compositioti acodiny to any ofdairns 28 30, 2 wharéth the rath ofthe hydrophith reS precursor to the hy&ophoS tetth precursor is no greater than 32. The antfouHg compStin accardirg to claim 31whe:efrLttte ratio of the hyt*thibb resin preursor to the: Sr:*dbio re*in no 34) greaterthan 1:10. 133. The antlioufing composition to a of claims 20 tb Z. wherein the hydt*obk resih precurs& is a themiosettlrig reS.M. The aSfSng; compos*ión acooSh to ahy df thrms 20 t33, $ where lfl: tt h)*Qpt%t* reSfr! prE4Jt$oY Øompfl$ss a precursor frra refli, an:øcryiic rss,na po'yester resin, wan epoxyntsr resin.3& the antffSinq crnpositkih ec*rdint& ctaini $4 wM:Sth Ptydmphabk r! pretu rtomprises a precursor for a:pOiYUrethafle ret Ut 3t The anSbullngvompSion accordMgt* any of caihs W wherein the hydrophobic sft ptetUrsbr aSihe hydrtphiRc4tesIb pteeursor res*t t be hØr* : Iflrtkøt withbv(hó matrix. (0r 15 ST. The antifoullnscomposftion according to dan 36, Whorein the.1 hydrophobic resin precursor art the htphWmJn precurs*' si uted $ 0 reaátion witfrt! iame hardener..St The antIfouWlgCWflpQflion accordingfo qy of Sims 20 to37, APEroIn tM hydr*phillc resin pr: ir one or more atidt* cgrflahlthg hydrpMc wiiwa rom&s a4 Thesof nn1S* hydrophIhc unsnntS: mi cer* pr patq&c h4tophthc unsaturated mo:nornn a The sflbding con pofliori accoi4t to any 0 c4airns 20 to7 wThi$nit4 hy* hflteSprecuisorpr1ses one or more: 1 poiyoxyethylsne pSit 40. The aPt1thuWg tonmsItton acdingb any of claims 20 to 39:, 9 wtiecMn the hardener composWei s present ii exi as ot the *tSr!t SSfr* 3Q to reactwith the tflophPbict$T pret:rs*the ty4rtphweiestn 41, The antifouRng composition according to any of otaims 20 to $0. further comprising one or mote soivents.42. The antifouhng composition accordihq to daim 41. wherein the soivert is water.43, The: ertifouUng oorr:positon ac.cC}r i.ng to etther of ciairps 41 or 42.wherein at east one of the resin precursors is present san emuson in the soiue.nt..44. The: anttfouiing composition acoprdi.ng to any of ojairns 41 to 43, wherew the yerf is present in the composition in an amount of from 0 to 60% by weight.. (045. An anttfouiing composttton substantia.iiy as hec&nbefdre described. r0 46. A method of forning an antifouiing coating. the method oomprisir, appying LC) toe sL}-fecs a comrf:on. aocordinq to any of cialma I to 45.. r2(1 47. Anarnciecompnsmo on at ieast a pcMtonof the. surface themof comm os o" acco cr10 to a' r' cars lo C 4$ A water borne Oraft comprising a composition according to any o ciaims I to 45 on at ieast a portion of the surface thereof.44 A method of forming an antifouiing composition substantiah as hereinbefore. described,