Antifouling paint composition with improved in-can stability

Abstract

The present embodiments relate to a method of producing an antifouling paint composition and to antifouling paint composition. The method comprises combining an acrylate-based polymer comprising at least one silyl ester bond with a reactive amide- and / or amine-containing antifouling agent and a monoisocyanate, and / or with an adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate, to form an antifouling paint composition comprising the adduct. The antifouling paint composition has improved in-can stability due to reduced risk of gel formation and viscosity increase.

Description

[0001] ANTIFOULING PAINT COMPOSITION WITH IMPROVED IN-CAN STABILITY

[0002] TECHNICAL FIELD

[0003] The present embodiments generally relate to antifouling paint compositions and methods of producing such antifouling paint compositions, and in particular to antifouling paint compositions having improved in-can stability.

[0004] BACKGROUND

[0005] Biofouling presents several issues for underwater structures and, thus, there is a general need to prevent and reduce biofouling on such structures. There are numerous antifouling approaches currently employed, including the use of specific coatings that deter biofouling, the use of toxins or biocides having antifouling activity as additives in coatings or paints for surfaces, and the use of mechanical cleaning of surfaces. The toxins or biocides can cause a physiological disruption or disturbance of the organism or result in killing the organism. The toxic or biocidal effects may occur prior to, during or after adhesion of the organism, with the outcome that the organism falls off the coated surface. Several different substances are employed for this purpose depending on the organism to deter from fouling surfaces. Certain coatings present surfaces that physically deter organisms so that they cannot easily adhere to the surface. These types of coatings are generally hydrophobic, smooth, slippery and have low friction, such as elastomers, including silicone rubbers. Self-polishing coatings (SPCs) slowly degrade over time to release a biocide that inhibits settling of organisms on the coated surface. The degradation is often caused by a slow, controlled hydrolysis of a component in the coating, usually a binder component and dissolution of water-soluble pigments.

[0006] There are both economic and environmental benefits of reducing biofouling on marine and freshwater installations. For example, biofouling reduces fuel efficiency for ships, reduces profitable operation time of ships during the biofouling cleaning procedures and decreases cooling power of cooling water equipment, to mention a few.

[0007] Silyl-acrylate is a common binder in antifouling paint compositions. However, a problem with silyl-acrylate as binder is that the viscosity of silyl-acrylate-based antifouling paint compositions increases over time. Such an increase in viscosity can lead to in-can gelation of the paint composition. Without being bound to theory, the mechanism of this gelation is believed to occur through water hydrolysis of the silyl ester bond resulting in a free carboxylic acid. In the presence of metal ions, especially zinc ions, a crosslinking between the carboxylic acid groups take place with an increased viscosity as a result. Lewis acids and bases can catalyze the hydrolysis reaction causing a faster gelation process. Water is essential for the hydrolysis process to take place. The water can come from various raw materials added in the paint formulation process and can even be formed when, for instance zinc oxide, reacts with rosin to form zinc rosinate during the formulation process.

[0008] To improve the in-can stability, water or moisture scavengers like tetraethyl orthosilicate (TEOS), also referred to as tetraethoxysilane (Si(OC2Hs)4), is commonly used to remove water from paint compositions. It is, however, very difficult to keep the paint composition entirely free of water, so even the use of excess water scavenger does not fully solve the problem with gelation and viscosity increase over time.

[0009] US 10,239,898 discloses compounds based on adducts with isocyanates and a method for preparation thereof comprising reacting 3-isocyanatopropyltrimethoxysilane with medetomidine, compositions comprising these compounds and also use thereof as, or for producing, coatings.

[0010] There is, therefore, a need to reduce risk of gelation and viscosity increase in antifouling paint compositions and thereby improve the in-can stability of the antifouling paint compositions.

[0011] SUMMARY

[0012] It is a general objective to improve in-can stability of antifouling paint compositions.

[0013] It is a particular objective to inhibit gelation and viscosity increase in antifouling paint composition.

[0014] This and other objectives are met by embodiments of the present invention.

[0015] The present invention is defined in the independent claims. Further embodiments of the invention are defined in the dependent claims.

[0016] An aspect of the invention relates to a method of producing an antifouling paint composition. The method comprises combining an acrylate-based polymer comprising at least one silyl ester bond with a reactive amide- and / or amine-containing antifouling agent and a monoisocyanate, and / or with an adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate, to form an antifouling paint composition comprising the adduct. Another aspect of invention relates to an antifouling paint composition comprising an adduct between a reactive amide- and / or amine-containing antifouling agent and a monoisocyante, and an acrylate-based polymer comprising at least one silyl ester bond.

[0017] A further aspect of the invention relates to use of a monoisocyanate as a dual water and reactive amide- and / or amine-containing antifouling agent scavenger in an antifouling paint composition comprising an acrylate-based polymer comprising at least one silyl ester bond and a reactive amide- and / or amine- containing antifouling agent.

[0018] The antifouling paint composition of the invention has improved in-can stability due to reduced risk of gelation and viscosity increase. The invention achieves this by deactivating and / or removing the reactive amide- and / or amine-containing antifouling agent so that it cannot catalyze hydrolysis of silyl ester bonds in the acrylate-based polymer binder. Such a deactivation and / or removal of the reactive amide- and / or amine-containing antifouling agents in the antifouling paint composition thereby reduces the hydrolysis of silyl ester bonds in the acrylate-based polymer binders, which further prevents or at least reduces the gelation of the antifouling paint composition and any viscosity increase over time.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The embodiments, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which:

[0021] Fig. 1 illustrates the presence of isocyanate in samples by the adsorption peak present at the wavenumber around 2275-2250 cm1;

[0022] Fig. 2 illustrates spectra of different combinations of medetomidine, pTSI and 1-M-2-P;

[0023] Fig. 3 illustrates viscosity of paint compositions over time for a control paint composition lacking antifouling agent (Paint 1), a reference antifouling paint composition (Paint 2) and an antifouling paint composition according to an embodiment (Paint 3); and

[0024] Fig. 4 illustrates viscosity of paint compositions over time for a control paint composition lacking antifouling agent (Paint 1), a reference antifouling paint composition lacking water scavenger (Paint 6), a reference antifouling paint composition comprising TEOS as water scavenger (Paint 2), and antifouling paint compositions according to embodiments (Paint 3; Paint 4; Paint 5). DETAILED DESCRIPTION

[0025] The foregoing and other aspects of the embodiments will now be described in more detail with respect to the description and methodologies provided herein. It should be appreciated that the invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to one of ordinary skill in the art.

[0026] The one of ordinary skill in the art will understand that terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless otherwise defined, all terms, including technical and scientific terms used in the description, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0027] As used in the description of the embodiments, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Thus, such references may be replaced with a reference to “one or more”, e.g., one, of the relevant component or integer. As used herein, all references to “one or more” of a particular component or integer will be understood to refer to from one to a plurality, e.g., two, three or four, of such components or integers. It will be understood that references to “one or more” of a particular component or integer will include a particular reference to one such integer. Also, as used herein, "and / or" refers to and encompasses any and all possible combinations of one or more of the associated listed items. Furthermore, the term "about," as used herein when referring to a measurable value, such as an amount of a compound, dose, time, temperature, and the like, refers to variations of 20 %, 10 %, 5 %, 1 %, 0.5 %, or even 0.1 % of the specified amount. When a range is employed, e.g., a range from x to y, it is it meant that the measurable value is a range from about x to about y, or any range or value therein including x and y. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and / or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0028] All patents, patent applications and publications referred to herein are incorporated by reference in their entirety. In the event of conflicting terminology, the present specification is controlling. The present embodiments generally relate to antifouling paint compositions and methods of producing such antifouling paint compositions, and in particular to antifouling paint compositions having improved in-can stability.

[0029] The present methods and antifouling paint compositions solve or at least reduce the problem of gelation and viscosity increase over time for paint compositions that use acrylate-based polymer binders comprising silyl ester bonds and that comprise antifouling agents comprising a reactive amide- and / or amine. Such reactive amide- and / or amine-containing antifouling agents act as catalyzers causing, in the presence of water, hydrolysis of silyl ester bonds in the acrylate-based polymer binders resulting in free carboxylic acid groups. In such a case, crosslinking between different carboxylic acid groups can occur, especially in the presence of metal ions, such as zinc ions (Zn2+). Crosslinking between different carboxylic acid groups causes gelation of the antifouling paint composition and an increase in viscosity.

[0030] The present invention solves this problem by deactivating and / or removing the reactive amide- and / or amine-containing antifouling agents so that the reactive amide- and / or amine-containing antifouling agents cannot catalyze hydrolysis of silyl ester bonds in the acrylate-based polymer binders. Such a deactivation and / or removal of the reactive amide- and / or amine-containing antifouling agents in the antifouling paint composition thereby reduces the hydrolysis of silyl ester bonds in the acrylate-based polymer binders, which further prevents or at least reduces the gelation of the antifouling paint composition and any viscosity increase over time. As a consequence, the antifouling paint composition of the invention has improved in-can stability.

[0031] In-can stability as used herein refers the storage stability and shelf life of the antifouling paint composition, such as when provided in a spray can or paint can. In particular, the present invention prevents or at least inhibits gelation and viscosity increase over time and thereby the stability and shelf life of the antifouling paint composition is improved.

[0032] An aspect of the invention relates to a method of producing an antifouling paint composition. The method comprises the step of combining an acrylate-based polymer comprising at least one silyl ester bond with a reactive amide- and / or amine-containing antifouling agent and a monoisocyanate, and / or with an adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate, to form an antifouling paint composition comprising the adduct. The monoisocyanate can react with any free reactive amide- and / or amine-containing antifouling agent, also referred to as reactive amide- and / or amine-containing biocide herein, to thereby form a reaction product, i.e., the adduct, between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate. The reaction between the monoisocyanate and the reactive amide- and / or amine- containing antifouling agent deactivates any free reactive amide- and / or amine-containing antifouling agent in the antifouling paint composition and thereby prevents or at least inhibits such free reactive amide- and / or amine-containing antifouling agents from catalyzing the hydrolysis of the silyl ester bond(s) of the acrylate-based polymer.

[0033] Free reactive amide- and / or amine-containing antifouling agent as used herein relates to any reactive amide- and / or amine-containing antifouling agent that has not reacted with the monoisocyanate to form the adduct and any reactive amide- and / or amine-containing antifouling agent not absorbed or adsorbed on surfaces in any pigment particles, when present in the antifouling paint composition. The monoisocyanate thereby acts as a scavenger for the reactive amide- and / or amine-containing antifouling agent by removing free reactive amide- and / or amine-containing antifouling agent from the antifouling paint composition by deactivating such free reactive amide- and / or amine-containing antifouling agent through the formation of the adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate. As a consequence, the amount of free reactive amide- and / or amine- containing antifouling agent that can act as a hydrolysis catalysator is thereby significantly reduced.

[0034] Deactivation of the reactive amide- and / or amine-containing antifouling agent as used herein refers to reacting the reactive amide- and / or amine-containing antifouling agent with the monoisocyanate to form the adduct and thereby deactivating the reactive amide- and / or amine-containing antifouling agent from acting as a hydrolysis catalysator for the silyl ester bond(s) of the acrylate-based polymer.

[0035] An adduct, also referred to as addition product, is a product of a direct addition of two or more distinct molecules resulting in a single reaction product containing all atoms of all components, i.e., the of the two or more distinct molecules. As an example, an adduct between medetomidine (formula I) and pTSI is presented in formula II and thereby consists of one medetomidine molecule and one pTSI molecule interconnected by an urea bond. Thus, an adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate consists of the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate interconnected by a bond formed between the reactive amide or amine in the reactive amide- and / or amine-containing antifouling agent and the isocyante group of the monoisocyanate. In an embodiment, the reactive amide- and / or amine-containing antifouling agent only contains a single reactive amide group or a single reactive amine group. In such an embodiment, the adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate consists of one molecule of the reactive amide- and / or amine-containing antifouling agent (one reactive amide- and / or amine-containing antifouling agent molecule) and one molecule of the monoisocyanate (one monoisocyanate molecule) interconnected by a bond.

[0036] The bond is an urea bond (-NH-CO-NH- or -NH-CO-N-) if the isocyanate group of the monoisocyanate reacts with a reactive amine group of the reactive amide- and / or amine-containing antifouling agent and a carbamoyl urea bond (-CO-NH-CO-) if the isocyanate group reacts with a reactive amide group of the reactive amide- and / or amine-containing antifouling agent.

[0037] Generally, if the reactive amide- and / or amine-containing antifouling agent comprises N> reactive amide and / or amine groups, such as N> reactive amide groups, N> reactive amine groups, or A / i>1 reactive amide groups and A / 2^1 reactive amine groups, wherein M + N? = N> , then the adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate consists of one molecule of the reactive amide- and / or amine-containing antifouling agent and M molecule(s) of the monoisocyanate, wherein <M<N. Thus, if the reactive amide- and / or amine-containing antifouling agent comprises multiple amide groups, multiple amine groups, or at least one amide group and at least one amine group, then the adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate consists of one molecule of the reactive amide- and / or amine-containing antifouling agent and one or more (up to the total number of reactive amide and / or amine groups in the reactive amide- and / or amine-containing antifouling agent) monoisocyanates.

[0038] In a preferred embodiment, N=M.

[0039] In another preferred embodiment, N=M= .

[0040] In an embodiment, the method comprises reacting the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate to form the adduct. In this embodiment, the combining step comprises combining the acrylate-based polymer comprising at least one silyl ester bond with the adduct. This embodiment thereby involves pre-reacting and thereby deactivating the reactive amide- and / or amine-containing antifouling agent with the monoisocyanate before combining with the acrylate-based polymer comprising at least one silyl ester bond. In the present embodiment, the acrylate-based polymer comprising at least one silyl ester bond is thereby mainly contacted with the adduct rather than any free reactive amide- and / or amine-containing antifouling agent.

[0041] In an embodiment, the reacting step comprises reacting the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate at a molar ratio of monoisocyanate : reactive amide- and / or amine-containing antifouling agent of >1 : 1. Thus, in an embodiment, equal molar ratio of monoisocyanate and reactive amide- and / or amine-containing antifouling agent or a molar excess of monoisocyanate is reacted to form the adduct. Such a molar ratio of > 1 : 1 reduces the amount of free, i.e., non-reacted, reactive amide- and / or amine-containing antifouling agent following the reaction between the monoisocyanate and the reactive amide- and / or amine-containing antifouling agent.

[0042] In a particular embodiment, the reacting step comprises reacting the reactive amide- and / or amine- containing antifouling agent and the monoisocyanate at a molar ratio of monoisocyanate : reactive amide- and / or amine-containing antifouling agent of 1 : 1 , i.e., equal molar amounts of the monoisocyanate and the reactive amide- and / or amine-containing antifouling agent.

[0043] In another particular embodiment, the reacting step comprises reacting the reactive amide- and / or amine- containing antifouling agent and the monoisocyanate at a molar ratio of monoisocyanate : reactive amide- and / or amine-containing antifouling agent of more than 1 : 1 , i.e., >1 : 1 and a molar excess of monoisocyanate.

[0044] In an embodiment, the reacting step comprises reacting solid reactive amide- and / or amine-containing antifouling agent and the monoisocyanate to form the adduct. In this embodiment, the reactive amide- and / or amine-containing antifouling agent is thereby in a solid form, such as a powder.

[0045] In another embodiment, the method comprises dissolving the reactive amide- and / or amine-containing antifouling agent in an organic solvent to form an antifouling agent solution. In such an embodiment, the reacting step comprises combining the antifouling agent solution and the monoisocyanate to form the adduct. The organic solvent is an organic solvent, in which the reactive amide- and / or amine-containing antifouling agent can be dissolved or at least dispersed. Illustrative, but non-limiting, examples of such organic solvents include alcohols excluding primary alcohols, ketones, benzene, alkylbenzene, halocarbon, petroleum-derived organic solvents, aromatic hydrocarbons and any combination thereof. Alcohols are preferably in the form of secondary or tertiary alcohols as primary alcohols can react with the monoisocyanate thereby interfering with the formation of the adduct between the monoisocyanate and the reactive amide- and / or amine-containing antifouling agent. Illustrative, but non-limiting, examples of alcohols that could be used as organic solvent include propan-2-ol, propane-1 ,2-diol, butane-1 ,2-diol, butane-1 ,3-diol, 1-methoxy-2-propanol, benzyl alcohol, and any combination thereof. An example of ketone that could be used as organic solvent is methyl-isobutyl ketone. An example of alkylbenzene is xylene, also referred to as xylol or dimethylbenzene. Another aromatic fluid-based solvent that could be used include Solvesso® fluids, such as Solvesso® 100, Solvesso® 150, Solvesso® 150 ND. The Sol vessor® fluids are member of the petroleum hydrocarbon family and consist predominately of C9-C11 aromatic hydrocarbons. In the case of the Solvesso® 150 family, the main constituent is C10 aromatic hydrocarbons, whereas in the case of Solvesso® 100, the main constituent is C9 aromatic hydrocarbons. Preferred halocarbons are organochlorine compounds, such as dicholoromethane. An example of a petroleum-derived organic solvent is white spirit, also referred to as mineral spirits, mineral turpentine, turpentine substitute and petroleum spirits in the art.

[0046] Hence, in an embodiment, the organic solvent is selected from the group consisting of propan-2-ol, propane-1 , 2-diol, butane-1 , 2-diol, butane-1 , 3-diol, 1-methoxy-2-propanol, methyl-isobutyl ketone, white spirit, benzyl alcohol, xylene, C9-C11 aromatic hydrocarbons, dicholoromethane, and any combination thereof.

[0047] A preferred organic solvent is 1-methoxy-2-propanol.

[0048] Another preferred organic solvent is xylene.

[0049] In an embodiment, the organic solvent is selected from the group consisting of 1-methoxy-2-propanal, xylene, and any combination thereof.

[0050] In the above-described embodiments, in-can stability is improved by inhibiting gelation and viscosity increase by deactivating the reactive amide- and / or amine-containing antifouling agent with the monoisocyanate prior to combining the reactive amide- and / or amine-containing antifouling agent with the acrylate-based polymer comprising at least one silyl ester bond. The deactivation of the reactive amide- and / or amine-containing antifouling agent through the formation of the adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate implies that no or at least less free reactive amide- and / or amine-containing antifouling agent is available as hydrolysis catalysator when combined with the acrylate-based polymer comprising at least one silyl ester bond.

[0051] In an alternative, or complementary, embodiment, the in-can stability can be improved by adhering reactive amide- and / or amine-containing antifouling agent onto pigment and / or carrier particles prior to or in connection with contacting the reactive amide- and / or amine-containing antifouling agent with the acrylate-based polymer comprising at least one silyl ester bond. Reactive amide- and / or amine- containing antifouling agent absorbed, adsorbed or otherwise adhering to the pigment and / or carrier particles is restricted from acting as a hydrolysis catalysator and is thereby prevented or at least inhibited from inducing gelation and viscosity increase in the antifouling paint composition. In this alternative or additional embodiment, the reactive amide- and / or amine-containing antifouling agent is thereby “deactivated” by adhering to pigment and / or carrier particles rather than mainly forming an adduct with the monoisocyanate. As is further discussed herein, these two different ways of deactivating the reactive amide- and / or amine-containing antifouling agent can be combined.

[0052] In an embodiment, the method further comprises the step of contacting the reactive amide- and / or amine- containing antifouling agent with pigment and / or carrier particles to at least partly adhere the reactive amide- and / or amine-containing antifouling agent onto the pigment and / or carrier particles. In this embodiment, the combing step comprises combining the acrylate-based polymer comprising at least one silyl ester bond with the pigment and / or carrier particles with adhering reactive amide- and / or amine- containing antifouling agent and the monoisocyanate.

[0053] In an embodiment, the method comprises dissolving the reactive amide- and / or amine-containing antifouling agent in an organic solvent to form an antifouling agent solution. In such an embodiment, the contacting step comprises contacting the antifouling agent solution with pigment and / or carrier particles to form a pigment or carrier solution, in which the reactive amide- and / or amine-containing antifouling agent is at least partly adhering to the pigment and / or carrier particles. In this embodiment, the combing step comprises combining the acrylate-based polymer comprising at least one silyl ester bond with the pigment or carrier solution and the monoisocyanate. The organic solvent, in which the reactive amide- and / or amine-containing antifouling agent is dissolved or dispersed, can be selected from the above-described embodiments of organic solvents. Hence, in an embodiment, the organic solvent is selected from the group consisting of alcohols excluding primary alcohols, ketones, benzene, alkylbenzene, halocarbon, petroleum-derived organic solvents, aromatic hydrocarbons and any combination thereof. In a particular embodiment, the organic solvent is selected from the group consisting of propan-2-ol, propane-1 , 2-diol, butane-1 ,2-diol, butane-1 ,3-diol, 1-methoxy- 2-propanol, methyl-isobutyl ketone, white spirit, benzyl alcohol, xylene, C9-C11 aromatic hydrocarbons, dicholoromethane, and any combination thereof.

[0054] In a particular embodiment, the method comprises mixing pigment particles, rosin solution and an organic solvent to form a rosinate and, as a byproduct of the rosination reaction, water. The method also comprises, in this embodiment, adding the monoisocyanate to the rosinate to form a water-scavenged rosinate solution. The reactive amide- and / or amine-containing antifouling agent and additional pigment particles, or a mixture of the reactive amide- and / or amine-containing antifouling agent and additional pigment particles, are then added to the water-scavenged rosinate solution to form a pigmented solution, in which the reactive amide- and / or amine-containing antifouling agent is at least partly adhering to the pigment particles and in which the monoisocyanate acts as a dual water and antifouling agent scavenger forming the adduct between non-adhering reactive amide- and / or amine-containing antifouling agent and the monoisocyanate. This embodiment of the method further comprises combining the pigmented solution and the acrylate-based polymer comprising at least one silyl ester bond to form the paint composition.

[0055] In this embodiment, the dual scavenging properties of the monoisocyanate is utilized together with adhering reactive amide- and / or amine-containing antifouling agent to the surface of pigment particles in order to suppress any gelation of the antifouling paint composition. Firstly, the reaction between pigment particles and the rosin solution produces a rosinate and, as an undesired byproduct, water. Water is needed for the hydrolysis reaction catalyzed by free reactive amide- and / or amine-containing antifouling agent. Thus, the monoisocyanate is added to act as a water scavenger by reacting with water. As a consequence, the monoisocyanate reduces the amount of free water available for the hydrolysis reaction. Secondly, the reactive amide- and / or amine-containing antifouling agent is added together with pigment particles or first mixed with pigment particles and then added to the water-scavenged rosinate solution. This means that the reactive amide- and / or amine-containing antifouling agent can adhere to the surface of the pigment particles prior to and / or upon contact with the water-scavenged rosinate solution. As a consequence, the amount of free, i.e., non-adhering, reactive amide- and / or amine-containing antifouling agent in the pigmented solution is low. Any such free reactive amide- and / or amine-containing antifouling agent can, however, react with non-reacted monoisocyanate to form the adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate. This means that the monoisocyanate acts, in this embodiment, as a dual scavenger by both removing water produced during the rosination reaction and removing any free, non-adhering reactive amide- and / or amine-containing antifouling agent.

[0056] In a particular embodiment, the method comprises mixing zinc oxide (ZnO) and / or cuprous oxide (CU2O), rosin solution and an organic solvent to form Zn-rosinate and / or Cu-rosinate and water. In this embodiment, the reactive amide- and / or amine-containing antifouling agent and additional zinc oxide and / or cuprous oxide or a mixture of the reactive amide- and / or amine-containing antifouling agent and additional zinc oxide and / or curpous oxide are added to the water-scavenged rosinate solution to form the pigmented solution, in which the reactive amide- and / or amine-containing antifouling agent is at least partly adhering to the zinc oxide and / or curpous oxide particles and in which the monoisocyanate acts as a dual water and antifouling agent scavenger forming the adduct between non-adhering reactive amide- and / or amine-containing antifouling agent and the monoisocyanate.

[0057] In a preferred embodiment, ZnO, CU2O or a mixture of ZnO and CU2O is used as pigment. Also other pigments can be used in the antifouling paint composition including, but not limited, to cupper (II) oxide (CuO), titanium dioxide (TiC>2) and iron oxide (FexOy). Thus, in an embodiment, the pigments or pigment particles are selected from the group consisting of cuprous oxide (copper (I) oxide), copper (II) oxide, zinc oxide, titanium dioxide, iron oxide, and any combination thereof.

[0058] As mentioned in the foregoing, instead of, or as a complement to, adhering the reactive amide- and / or amine-containing antifouling agent onto pigment particles, the reactive amide- and / or amine-containing antifouling agent, or at least a portion thereof, could be adhered to the surface of carrier particles that do not necessarily have to be pigments. An illustrative, but non-limiting, example of such carrier particles includes silica particles.

[0059] The dual scavenging properties of the monoisocyanate can be used also in paint formulations, in which the reactive amide- and / or amine-containing antifouling agent, or at least a portion thereof, is not adhering to the surface of any pigment and / or carrier particles. Thus, also other ingredients and components of the paint formulation, or other reactions taking place in the paint formulation than the reaction between pigment particles and the rosin solution producing a rosinate and water, may contain or lead to the production of water. In such cases, the water scavenging effect of the monoisocyanate could be utilized to reduce the amount of free water available for the hydrolysis reaction.

[0060] The monoisocyanate does not only have dual scavenging properties but may in fact have ternary scavenging properties by also reacting with any primary alcohols present in the paint formulation and thereby reducing the amount of free primary alcohols. Such alcohol scavenging could be beneficial for the paint formulation for various reasons. Firstly, primary alcohols, such as ethanol, desorbs the reactive amide- and / or amine-containing antifouling agent adhering to pigment particles to thereby result in free reactive amide- and / or amine-containing antifouling agent in the paint formulation. The free reactive amide- and / or amine-containing antifouling agent may then catalyze hydrolysis of silyl ester bonds in the acrylate-based polymer binder, which may lead to gelation as previously described herein. Secondly, the free reactive amide- and / or amine-containing antifouling agent implies quicker leakage of the reactive amide- and / or amine-containing antifouling agent from the paint and thereby a reduction of the antifouling lifetime of the paint.

[0061] In an embodiment, the reactive amide- and / or amine-containing antifouling agent comprises medetomidine, or an enantiomer, base or salt thereof.

[0062] Medetomidine, also referred to as (±)-4-[1-(2,3-dimethylphenyl)ethyl)-1 / - / -imidazole, see formula I, is a highly selective a2-adrenoreceptor agonist. There are two tautomers of the imidazole group of medetomidine resulting in 4-[1-(2,3-dimethylphenyl)ethyl)-1 / 7-imidazole as shown in formula I or its tautomer 5-[1 -(2, 3-d imethylp henyl)ethyl)- 1 H-imidazole.

[0063] Medetomidine is a highly efficient inhibitor of barnacles and impede cuprid larval settlement already at low concentrations, 1-10 nM. Medetomidine interacts with octopamine receptors in the barnacle cyprid larva, causing the legs of the larva to kick and thereby prevents the larva from settling onto medetomidine containing or releasing surface. Medetomidine has also shown effect on other hard fouling, such as tube worms.

[0064] Medetomidine is a racemic mixture of the two optical enantiomers, the levo- and dextro-rotary optical isomers (Journal of pharmacology and experimental therapeutics, 259: 848-854, 1991 ; European Journal of Pharmacology, 195: 193-199, 1991) with generic names levomedetomidine and dexmedetomidine, respectively. A process for the preparation of the racemic mixture of medetomidine and related intermediates is disclosed in WO 2011 / 070069. Many of the previous medetomidine syntheses used expensive 4-substituted imidazole derivatives as starting material. However, the synthesis presented in WO 2011 / 070069 is made from affordable commercially available starting materials, where the imidazole ring is instead formed during the synthesis. WO 2013 / 014428 describes a novel process of preparing medetomidine, including novel intermediates thereof, avoiding potentially disadvantageous use of imidazole derivatives as starting material. WO 2016 / 120635 relates to new processes for preparation of intermediates, such as 3-arylbutanals, useful in the synthesis of medetomidine.

[0065] The terms medetomidine, dexmedetomidine, and levomedetomidine as used herein include salts, bases and solvates thereof unless specifically stated otherwise. Acceptable salts of medetomidine, dexmedetomidine, and levomedetomidine include acid addition salts and base addition salts. Such salts may be formed by conventional means, for example by reaction of a free acid or a free base form of medetomidine, dexmedetomidine, and levomedetomidine with one or more equivalents of an appropriate acid or base, optionally in a solvent, or in a medium in which the salt is insoluble, followed by removal of the solvent, or the medium, using standard techniques, e.g., in vacuum or by freeze-drying. Salts may also be prepared by exchanging a counter-ion of medetomidine, dexmedetomidine, and levomedetomidine in the form of a salt with another counter-ion, for example using a suitable ion exchange resin. An illustrative, but non-limiting, example of a salt of medetomidine is medetomidine hydrochloride. For the avoidance of doubt, other acceptable derivatives of medetomidine, dexmedetomidine, and levomedetomidine are included within the scope of the invention, e.g., solvates, etc.

[0066] The base form of medetomidine is distributed by the company l-Tech AB under the product name SELEKTOPE®.

[0067] In the following, various aspects and embodiments of the present invention are described in further detail with reference to medetomidine. These aspects and embodiments also encompass an enantiomer of medetomidine, such as dexmedetomidine or levomedetomidine, a salt of medetomidine, a salt of dexmedetomidine, or a salt of levomedetomidine, or a base of medetomidine, a base of dexmedetomidine, or a base of levomedetomidine collectively denoted medetomidine, or an enantionmer, base or salt thereof herein. Thus, reference to medetomidine herein should be regarded as relating to medetomidine, a salt of medetomidine, a base of medetomidine, dexmedetomidine, a salt of dexmedetomidine, a base of dexmedetomidine, levomedetomidine, a salt of levomedetomidine, and / or a base of levomedetomidine unless indicated otherwise.

[0068] In an embodiment, the monoisocyanate is para-toluenesulfonyl isocyanate (pTSI).

[0069] In a particular embodiment, the reactive amide- and / or amine-containing antifouling agent is medetomidine, or an enantiomer, base or salt thereof, and the monoisocyanate is pTSI. In such a particular embodiment, the adduct between medetomidine and pTSI, pTSI-medetomidine is represented by formula II below:

[0070] The reactive amine-group of medetomidine reacts with the isocyanate group of pTSI forming an urea bond, thereby deactivating the reactive amine-group of medetomidine in the adduct between pTSI and medetomidine.

[0071] In an embodiment, the acrylate-based polymer comprising at least one silyl ester bond comprises a silyl acrylate polymer, a metal acrylate polymer comprising at least one silyl ester bond, a silyl acrylate and metal acrylate copolymer, and any combination thereof.

[0072] Illustrative, but non-limiting, examples of metal acrylate polymers comprising at least one silyl ester bond that could be used as acrylate-base polymer are copper acrylate polymer comprising at least one silyl ester bond, zinc acrylate polymer comprising at least one silyl ester bond, and any combination thereof. In a preferred embodiment, the acrylate-based polymer is a silyl acrylate polymer or a silyl acrylate and metal acrylate copolymer, and more preferably a silyl acrylate polymer.

[0073] In an embodiment, the acrylate-based polymer comprising at least one silyl ester bond is a self-polishing polymer. In such an embodiment, the antifouling paint composition is a self-polishing antifouling paint composition. An example of a self-polishing acrylate-based polymer is a silyl acrylate.

[0074] Another aspect of the invention relates to an antifouling paint composition. The antifouling paint composition comprise an adduct between a reactive amide- and / or amine-containing antifouling agent and a monoisocyante. The antifouling agent also comprises an acrylate-based polymer comprising at least one silyl ester bond.

[0075] In an embodiment, the antifouling paint composition further comprises an organic solvent.

[0076] In a particular embodiment, the organic solvent is selected from the group consisting of an alcohol other than a primary alcohol, benzene, an alkylbenzene, a halocarbon, a ketone, an aromatic hydrocarbon, a petroleum-derived organic solvent, and any combination thereof.

[0077] In a preferred embodiment, the organic solvent is selected from the group consisting of propan-2-ol, propane-1 , 2-diol, butane-1 ,2-diol, butane-1 ,3-diol, 1-methoxy-2-propanol, methyl-isobutyl ketone, white spirit, benzyl alcohol, xylene, dicholoromethane, C9-C11 aromatic hydrocarbons, and any combination thereof.

[0078] In a most preferred embodiment, the organic solvent is 1 -methoxy-2-propanol.

[0079] In another preferred embodiment, the organic solvent is xylene.

[0080] In a further preferred embodiment, the organic solvent is selected from the group consisting of 1 -methoxy- 2-propanal, xylene, and any combination thereof.

[0081] In an embodiment, the reactive amide- and / or amine-containing antifouling agent comprises medetomidine, or an enantiomer, base or salt thereof. In a particular embodiment, reactive amide- and / or amine-containing antifouling agent is medetomidine, or an enantiomer, base or salt thereof In an embodiment, the monoisocyante comprises pTSI. In an embodiment, the monoisocyante is pTSI.

[0082] In another embodiment, the comprises a mixture of two or more monoisocyanates, such as a mixture of pTSI and TEOS.

[0083] In an embodiment, the acrylate-based polymer comprising at least one silyl ester bond comprises a silyl acrylate polymer, a metal acrylate polymer comprising at least one silyl ester bond, preferably copper acrylate polymer comprising at least one silyl ester bond and / or zinc acrylate polymer comprising at least one silyl ester bond, a silyl acrylate and metal acrylate copolymer, and any combination thereof.

[0084] In a particular embodiment, the acrylate-based polymer comprising at least one silyl ester bond is a silyl acrylate polymer.

[0085] In an embodiment, the acrylate-based polymer comprising at least one silyl ester bond is an acrylate- based self-polishing polymer comprising at least one silyl ester bond. In this embodiment, the antifouling paint composition is a self-polishing antifouling paint composition.

[0086] In an embodiment, the antifouling paint composition further comprises pigments or pigment particles.

[0087] In a particular embodiment, the pigments or pigment particles are selected from the group consisting of zinc oxide, cuprous oxide, copper (II) oxide, titanium dioxide, an iron oxide, and any combination thereof.

[0088] In a preferred embodiment, the pigments or pigment particles are selected from the group consisting of zinc oxide, cuprous oxide, and any combination thereof.

[0089] In an embodiment, the antifouling paint composition further comprises the reactive amide- and / or amine- containing antifouling agent adhered, such as absorbed or adsorbed, to a surface of the pigment particles.

[0090] In an embodiment, the antifouling paint composition further comprises carrier particles, preferably silica particles. In such an embodiment, the reactive amide- and / or amine-containing antifouling agent is adhered, such as absorbed or adsorbed, to a surface of the pigment particles. In an embodiment, the antifouling paint composition also comprises a rosinate.

[0091] In a preferred embodiment, the rosinate is selected from the group consisting of zinc rosinate, copper rosinate, and any combination thereof, preferably zink rosinate.

[0092] In an embodiment, the antifouling paint composition comprises, preferably consists of: the acrylate-based polymer comprising at least one silyl ester bond, preferably silyl acrylate polymer, at from 5 up 25 % by weight; the adduct, preferably an adduct between para-toluenesulfonyl isocyanate and medetomidine, or an enantiomer, base or salt thereof, at from 0.1 up to 1 % by weight; an organic solvent, preferably 1-methoxy-2-propanol and / or xylene, at from 10 up to 50 % by weight; pigment particles, preferably zinc oxide (ZnO) and / or cuprous oxide (CU2O), at from 5 up to 50 % by weight; and rosinate at from 1 up to 5 % by weight.

[0093] In an embodiment, at least one other biocide other than medetomidine is included in the antifouling paint composition. This at least one other biocide could be an antifouling agent, an algicide, a fungicide, a herbicide or a combination thereof.

[0094] Non-limiting, but illustrative examples of such biocides other than medetomidine that can be used according to the embodiments are listed in WO 2012 / 175469 on page 11 , line 16 to page 12, line 10 and in WO 2013 / 182641 on page 10, line 22 to page 13, line 2, the teaching of which is hereby incorporated by reference with regard to biocides that can be used according to the embodiments.

[0095] Other non-limiting biocides that can be used according to the embodiments include, but are not limited to, chlorothalonil (2,4,5,6-tetrachlorobenzene-1 ,3-dicarbonitrile), dichlofluanid (N- {[dichloro(fluoro)methyl]sulfanyl}-N',N'-dimethyl-N-phenylsulfuric diamide), DCOIT (4,5-dichloro-2-n- octyl-4-isothiazolin-3-one), cybutryne (2-N-tert-butyl-4-N-cyclopropyl-6-methylsulfanyl-1 ,3,5-triazine-2,4- diamine), DCMU (3-(3,4-dichlorophenyl)-1 ,1 -dimethylurea), tolylfluanid (N- [dichloro(fluoro)methyl]sulfanyl-N-(dimethylsulfamoyl)-4-methylaniline), zinc pyrithione (bis(2- pyridylthio)zinc 1 ,1 '-dioxide), copper pyrithione (bis(2-pyridylthio)copper 1 ,1 -dioxide), cybutryne (2-N- tert-butyl-4-N-cyclopropyl-6-methylsulfanyl- 1 , 3, 5-triazi ne-2,4-diami ne), zinc ethane-1 ,2- diylbis(dithiocarbamate), zinc bis(dimethylthiocarbamates, manganese ethylene-1 , 2-bisdithiocarbamate polymer, 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1 H-pyrrole-3-carbonitrile (tralopyril), and a mixture thereof.

[0096] Medetomidine has specific actions against hard fouling, in particular barnacle cyprids, but typically no effect on algal growth. Accordingly, at least one other biocide, such as an algicide, could be used to prevent algal growth as well.

[0097] The antifouling paint composition may optionally comprise other ingredients including, but not limited to, one or more fillers or extenders, such as talc, CaCOs, BaSO4, nepheline syenite and / or mica (phyllosilicates), one or more rheology modifiers (thixotropic agents, thickeners), such as fumed silica, silica, polyamide wax dispersion and / or clay, such as bentonite clay or organic derivative thereof, one or more plasticizers, such as chlorinated wax and / or butylated triphenyl phosphate esters, and / or one or more biocides.

[0098] The present invention also relates to the use of a monoisocyanate, preferably para-toluenesulfonyl isocyanate, as a dual water and reactive amide- and / or amine-containing antifouling agent scavenger in an antifouling paint composition comprising an acrylate-based polymer comprising at least one silyl ester bond, preferably a silyl acrylate polymer, and a reactive amide- and / or amine-containing antifouling agent, preferably medetomidine, or an enantiomer, base or salt thereof.

[0099] In an embodiment, the monoisocyanate is used as a ternary scavenger, i.e., a water scavenger, a primary alcohol scavenger and a reactive amide- and / or amine-containing antifouling agent scavenger.

[0100] EXAMPLES

[0101] EXAMPLE 1

[0102] This example involved deactivating medetomidine by reacting it to para-toluenesulfonyl isocyanate (pTSI) to form the adduct medetomidine-pTSI.

[0103] Medetomidine (1.0075 g) was dissolved in 1-methoxy-2-propanol (5 g, 1-M-2-P) in a 20 mL vial. 1.0158 g pTSI (1 equivalent compared to medetomidine) was added to the vial. The exothermic reaction between pTSI and medetomidine started immediately. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used to confirm conversion of medetomidine and pTSI into the adduct medetomidine-pTSI after 15 minutes. The catalytical properties of medetomidine, such as in the hydrolysis of silyl acrylate, were deactivated in this Example 1 by forming the adduct medetomidine-pTSI.

[0104] EXAMPLE 2

[0105] This example scavenged alcohols by reacting 1-M-2-P with the pTSI.

[0106] 1-M-2-P (C: 1.880 g, D: 1.8949 g, and E: 1.8807 g, respectively) was added to three 20 mL vials (C, D, and E, respectively). Medetomidine (C: 0.520 g, and E: 0.509 g, respectively) was added and dissolved in the vials C and E. pTSI (0.5 g, 1 equivalent with respect to medetomidine) was added to vials D and E. The exothermic reactions between pTSI and medetomidine and between pTSI and 1-M-2-P started immediately. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used to confirm conversion of medetomidine and pTSI; and 1-M-2-P and pTSI into the adduct of medetomidine- pTSI and pTSI-1 -M-2-P after 10 and 12 min for sample D and E, respectively, see Figs. 1 and 2. As can be seen in Fig. 1 , there was no isocyante present in any of the samples except pTSI, which indicated that all isocyanate had reacted in the samples pTSI in 1-M-2-P (t=10 min) and pTSkmedetomidine (1 :1) in 1- M-2-P (t=12 min).

[0107] Fig. 2 illustrates spectra of different combinations of medetomidine, pTSI and 1 -M-2-P. The adsorption peak for carbonyl on urethane can be seen at 1745 cm1, which indicates that pTSI and 1-M-2-P had reacted, which can be seen in both sample pTSI in 1-M-2-P (t=10 min) and pTSkmedetomidine (1 :1) in 1-M-2-P (t=12 min). The difference between these two samples was that medetomidine was present in sample pTSkmedetomidine (1 :1) in 1-M-2-P (t=12 min), and there was a significant difference in the adsorption peak of carbonyl on the urethane even if nearly all isocyanate had reacted. This indicated that the isocyanate had partially reacted with 1-M-2-P and partially with medetomidine in the sample pTSkmedetomidine (1 :1) in 1-M-2-P (t=12 min).

[0108] The data thereby shows that pTSI had dual actions by both deactivating the catalytical properties of medetomidine by the formation of the adduct medetomidine-pTSI and scavenging alcohols by reacting with 1-M-2-P. Such alcohol scavenging is beneficial from a gelation standpoint. In more detail, when using TEOS as a water scavenger, ethanol is produced in the reaction between TEOS and water (Si(OCH2CH3)4 + 4H2O Si(OH)4 + 4CH3CH2OH). Ethanol desorbs medetomidine from any prigment particles, which increases the rate in which the pain gels. Also, the desorption of medetomidine from the pigment particles by ethanol results in free medetomidine in the paint system, which means that medetomidine is leaching out quicker from the paint, thereby reducing the antifouling lifetime of the paint. EXAMPLE 3

[0109] This example investigated the viscosity of three paint compositions.

[0110] Three paint compositions were prepared to see how medetomidine deactivated in an adduct affected the viscosity of the paint compositions over time compared to a control paint formulation comprising free medetomidine. The paint compositions were prepared by adding all the solid ingredients (CU2O, ZnO) and, if present, medetomidine or medetomidine-pTSI solution, to paint cans. The liquid components were added to the dry mixture, in the following order, Rosin-solution, xylene, TEOS and silyl-acrylate solution. All component was mixed together with a spatula followed by 5 min shaking in the paint shaker.

[0111] Table 1 - Paint formulations

[0112] ‘Prepared as Example 1

[0113] The viscosity overtime was monitored with a Krebs viscometer (TQC Sheen, Model: SH480 Digital Krebs viscometer, at room temperature (21 °C)) and the results are presented in Fig. 3. The TQC Sheen Krebs viscometer is a Krebs viscometer used for measuring viscosity of paints. The Krebs viscometer uses a paddle immersed in a vessel containing a fixed volume of the paint under test. A constant speed motor drives the paddle at exactly 200 r.p.m. and the torque induced is proportional to the viscosity of the sample and is converted into viscosity (cP), Krebs units (KU) and weight units (g). Reacting medetomidine with pTSI to form the adduct before adding it to the formulation reduced the catalytic action of medetomidine in hydrolysis of the paint binder, i.e. , silyl acrylate. Paint 3 behaved similar to the reference paint composition (Paint 1) without any added medetomidine and there was only a very small increase of viscosity over time. Paint 2 with free medetomidine suffered from a significant increase in viscosity over time as the free medetomidine, which is a Lewis base, catalyzed the hydrolysis of the silyl acrylate.

[0114] EXAMPLE 4

[0115] This example compared the viscosity change over time for different paint compositions using different drying agents / water scavengers.

[0116] The ingredients of the paint compositions are presented in Table 2 below.

[0117] Table 2 - Ingredients in paint compositions

[0118] Six paint compositions were prepared by mixing the ingredients in a special order to optimize the function of each ingredient.

[0119] Step 1 : Rosination

[0120] ZnO (5 g), rosin solution and xylene were mixed with a spatula and left for 30 min at room temperature (21 °C) to let the rosin and ZnO react and form Zn-rosinate and water.

[0121] Step 2: Drying with drying agent / water scavenger TEOS and / or pTSI was added to the Zn-rosinate solution, see Table 3, and mixed to let the drying agent / water scavenger (TEOS and / or pTSI) react with any water in the Zn-rosinate solution present for 30 min. In paint composition no. 3, TEOS and pTSI were mixed in at the same time. In paint composition no. 4, pTSI were added 30 min after the addition of TEOS, i.e., just before the start of Step 3.

[0122] Step 3: Adsorption of medetomidine to pigment particles

[0123] The rest of the ZnO was added together with medetomidine and CU2O. All components were mixed with a spatula and left for 30 min to let any free medetomidine have a chance to adhere to the surface of the pigment particles.

[0124] Step 4: Addition of paint binder

[0125] Silyl acrylate solution was mixed in with a spatula followed by shaking of the can in a paint shaker for 5 min.

[0126] There six paint compositions in accordance with above and Table 3 below.

[0127] Table 3 - Water scavengers in paint compositions

[0128] Right after the paint compositions were finalized in step 4, the time 0 viscosity was determined on a Krebs viscometer (TQC Sheen, Model: SH480 Digital Krebs viscometer, at room temperature, 21 °C). The viscosity of the paint compositions was followed over time and is presented in Fig. 4.

[0129] The reference paint composition with no drying agent / water scavenger (no. 6) showed a dramatic increase in viscosity over time. The paint composition with only TEOS as a drying agent / water scavenger (no. 2) improved the stability of the paint composition as compared to paint composition no. 6. However, there was still a slow increase in viscosity over time for paint composition no. 2. The paint compositions with pTSI as sole drying agent / water scavenger (no. 5) or pTSI in combination (togher or serial) with TEOS (nos. 3 and 4) significantly slowed down the increase in viscosity over time.

[0130] EXAMPLE 5

[0131] This example shows that medetomidine is still active as antifouling agent in a formulation using pTSI as dual water and medetomidine scavenger in real paint formulations applied to test panel and submerged in field tests

[0132] 12 different paint formulations were prepared using three different binder systems. Each binder was used in four different paint formulations. The four different formulations were:

[0133] Paint no. 1 a reference paint formulation without medetomidine used to show how much barnacles attached to a test panel when there was now biocide present in the coating;

[0134] Paint no. 2 a reference paint formulation with medetomidine used to show how much barnacles attached to a test panel when there was a biocide present in the coating;

[0135] Paint no. 3 a paint formulation with medetomidine where pTSI have been used as a dual water and medetomidine scavenger; and

[0136] Paint no. 4 a paint formulation with medetomidine added as a scavenged biocide (medetomidine was mixed with pTSI prior to mixing it into the paint formulation to form the adduct medetomidine-pTSI) to show that medetomidine was still effective in a coating on a test panel in field test.

[0137] Premix of medetomidine and pTSI

[0138] Medetomidine 0.5 g was dissolved in 1-M-2-P (1.86 g) in a vial, followed by addition of pTSI (0.49 g) to simulate scavenged medetomidine. The exothermic reaction was very quick and completed in a few minutes.

[0139] Paint formulations and application

[0140] Paint formulations were prepared by mixing the constituents of each paint (Tables 4-6) in paint cans. The paints were applied on plastic test panels by spraying.

[0141] Field test The test panels were attached to an aluminum frame and submerged on the Swedish west coast during summer. After 83 days in the water the test panels were inspected and the area on each test panel covered with barnacles were estimated. Table 4 - Silyl-acrylate formulations

[0142] * This is premixed medetomidine and pTSI (17.5 % by weight medetomidine)

[0143] Table 5 - Rosin formulations

[0144]

[0145] * This is premixed medetomidine and pTSI (17.5 % by weight medetomidine)

[0146] Table 6 - Zinc-acrylate formulations

[0147] * This is premixed medetomidine and pTSI (17.5 % by weight medetomidine) The test panels coated with paint formulations where pTSI had been added (paint formulations 3) to scavenge water and free medetomidine as well as formulations where scavenged medetomidine (paint formulations 4) was added performed equally well to the reference test panel with free medetomidine (paint formulations 2) and all test panels with medetomidine performed considerably better than the reference test panels without medetomidine (paint formulations 1 ) regardless of the binder system used in the formulations.

[0148] The embodiments described above are to be understood as a few illustrative examples of the present invention. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible. The scope of the present invention is, however, defined by the appended claims.

Claims

CLAIMS1. A method of producing an antifouling paint composition, the method comprises the step of combining an acrylate-based polymer comprising at least one silyl ester bond with a reactive amide- and / or amine-containing antifouling agent and a monoisocyanate, and / or with an adduct between the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate, to form an antifouling paint composition comprising the adduct.

2. The method according to claim 1 , further comprising the step of reacting the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate to form the adduct, wherein the combining step comprises combining the acrylate-based polymer comprising at least one silyl ester bond with the adduct.

3. The method according to claim 2, wherein the reacting step comprises reacting the reactive amide- and / or amine-containing antifouling agent and the monoisocyanate at a molar ratio of monoisocyanate : reactive amide- and / or amine-containing antifouling agent of >1 : 1 , preferably 1 : 1.

4. The method according to claim 2 or 3, wherein the reacting step comprises reacting solid reactive amide- and / or amine-containing antifouling agent and the monoisocyanate to form the adduct.

5. The method according to claim 2 or 3, further comprising dissolving the reactive amide- and / or amine-containing antifouling agent in an organic solvent to form an antifouling agent solution, wherein the reacting step comprises combining the antifouling agent solution and the monoisocyanate to form the adduct.

6. The method according to any one of claims 1 to 5, further comprising the step of contacting the reactive amide- and / or amine-containing antifouling agent with pigment particles and / or carrier particles to at least partly adhere the reactive amide- and / or amine-containing antifouling agent onto the pigment particles and / or carrier particles, wherein the combining step comprises combining the acrylate-based polymer comprising at least one silyl ester bond with the pigment particles and / or carrier particles with adhering reactive amide- and / or amine-containing antifouling agent and the monoisocyanate.

7. The method according to claim 6, further comprising dissolving the reactive amide- and / or amine- containing antifouling agent in an organic solvent to form an antifouling agent solution, whereinthe contacting step comprises contacting the antifouling agent solution with pigment particles and / or carrier particles to form a pigment or carrier solution, in which the reactive amide- and / or amine- containing antifouling agent is at least partly adhering to the pigment particles and / or carrier particles; and the combing step comprises combining the acrylate-based polymer comprising at least one silyl ester bond with the pigment or carrier solution and the monoisocyanate.

8. The method according to claim 5 or 7, wherein the organic solvent is selected from the group consisting of an alcohol excluding primary alcohols, a ketone, benzene, alkylbenzene, a halocarbon, a petroleum-derived organic solvent, an aromatic hydrocarbons, and any combination thereof, preferably selected from the group consisting of propan-2-ol, propane-1 , 2-diol, butane-1 ,2-diol, butane-1 ,3-diol, 1- methoxy-2-propanol, methyl-isobutyl ketone, white spirit, benzyl alcohol, xylene, C9-C11 aromatic hydrocarbons, dicholoromethane, and any combination thereof, more preferably selected from the group consisting of 1-methoxy-2-propanol, xylene, and any combination thereof.

9. The method according to claim 6, 7 or 8 when dependent on claim 7, further comprising: mixing pigment particles, preferably zinc oxide (ZnO) and / or cuprous oxide (CU2O), rosin solution and an organic solvent to form a rosinate, preferably Zn-rosinate and / or Cu-rosinate, and water; adding the monoisocyanate to the rosinate to form a water-scavenged rosinate solution; adding the reactive amide- and / or amine-containing antifouling agent and additional pigment particles, preferably zinc oxide and / or cuprous oxide, or a mixture of the reactive amide- and / or amine- containing antifouling agent and additional pigment particles, preferably zinc oxide and / or curpous oxide, to the water-scavenged rosinate solution to form a pigmented solution, in which the reactive amide- and / or amine-containing antifouling agent is at least partly adhering to the pigment particles and in which the monoisocyanate acts as a dual water and antifouling agent scavenger forming the adduct between non-adhering reactive amide- and / or amine-containing antifouling agent and the monoisocyanate; and combining the pigmented solution and the acrylate-based polymer comprising at least one silyl ester bond to form the paint composition.

10. The method according to any one of claim 1 to 9, wherein the reactive amide- and / or amine- containing antifouling agent comprises medetomidine, or an enantiomer, base or salt thereof.11 . The method according to any one of claims 1 to 10, wherein the monoisocyante comprises paratoluenesulfonyl isocyanate.

12. The method according to any one of claims 1 to 11 , wherein the acrylate-based polymer comprising at least one silyl ester bond comprises a silyl acrylate polymer, a metal acrylate polymer comprising at least one silyl ester bond, preferably copper acrylate polymer comprising at least one silyl ester bond and / or zinc acrylate polymer comprising at least one silyl ester bond, a silyl acrylate and metal acrylate copolymer, and any combination thereof.

13. The method according to any one of claims 1 to 12, wherein the acrylate-based polymer comprising at least one silyl ester bond is a self-polishing polymer comprising at least one silyl ester bond; and the antifouling paint composition is a self-polishing antifouling paint composition.

14. An antifouling paint composition comprising: an adduct between a reactive amide- and / or amine-containing antifouling agent and a monoisocyante; and an acrylate-based polymer comprising at least one silyl ester bond.

15. The antifouling paint composition according to claim 14, further comprising an organic solvent, preferably selected from the group consisting of an alcohol excluding primary alcohols, a ketone, benzene, alkylbenzene, a halocarbon, a petroleum-derived organic solvent, an aromatic hydrocarbons, and any combination thereof, preferably selected from the group consisting of propan-2-ol, propane-1 ,2- diol, butane-1 ,2-diol, butane-1 ,3-diol, 1-methoxy-2-propanol, methyl-isobutyl ketone, white spirit benzyl alcohol, xylene, C9-C11 aromatic hydrocarbons, dicholoromethane, and any combination thereof, more preferably selected from the group consisting of 1-methoxy-2-propanol, xylene, and any combination thereof.

16. The antifouling paint composition according to claim 14 or 15, wherein the reactive amide- and / or amine-containing antifouling agent comprises medetomidine, or an enantiomer, base or salt thereof.

17. The antifouling paint composition according to any one of claims 14 to 16, wherein the monoisocyante comprises para-toluenesulfonyl isocyanate.

18. The antifouling paint composition according to any one of claims 14 to 17, wherein the acrylate- based polymer comprising at least one silyl ester bond comprises a silyl acrylate polymer, a metal acrylatepolymer comprising at least one silyl ester bond, preferably copper acrylate polymer comprising at least one silyl ester bond and / or zinc acrylate polymer comprising at least one silyl ester bond, a silyl acrylate and metal acrylate copolymer, and any combination thereof.

19. The antifouling paint composition according to any one of claims 14 to 18, wherein the acrylate-based polymer comprising at least one silyl ester bond is an acrylate-based selfpolishing polymer comprising at least one silyl ester bond; and the antifouling paint composition is a self-polishing antifouling paint composition.

20. The antifouling paint composition according to any one of claims 14 to 19, further comprising pigment particles, preferably zinc oxide (ZnO) and / or cuprous oxide (CU2O).

21. The antifouling paint composition according to claim 20, further comprising the reactive amide- and / or amine-containing antifouling agent adhered to a surface of the pigment particles.

22. The antifouling paint composition according to any one of claims 14 to 21 , further comprising carrier particles, preferably silica particles, and the reactive amide- and / or amine-containing antifouling agent adhered to a surface of the pigment particles.

23. The antifouling paint composition according to any one of claims 14 to 22, further comprising a rosinate, preferably zinc rosinate, cupper rosinate, and any combination thereof.

24. The paint composition according to any one of claims 14 to 23, wherein the antifouling paint composition comprises, preferably consists of: the acrylate-based polymer comprising at least one silyl ester bond, preferably silyl acrylate polymer, at from 5 up 25 % by weight; the adduct, preferably an adduct between para-toluenesulfonyl isocyanate and medetomidine, or an enantiomer, base or salt thereof, at from 0.1 up to 1 % by weight; an organic solvent, preferably 1-methoxy-2-propanol and / or xylene, at from 10 up to 50 % by weight; pigment particles, preferably zinc oxide (ZnO) and / or cuprous oxide (CU2O), at from 5 up to 50 % by weight; and rosinate at from 1 up to 5 % by weight.

25. Use of a monoisocyanate, preferably para-toluenesulfonyl isocyanate, as a dual water and reactive amide- and / or amine-containing antifouling agent scavenger in an antifouling paint composition comprising an acrylate-based polymer comprising at least one silyl ester bond, preferably a silyl acrylate polymer, and a reactive amide- and / or amine-containing antifouling agent, preferably medetomidine, or an enantiomer, base or salt thereof.

26. The use according to claim 25, wherein the use comprises use of the monoisocyanate as a ternary scavenger in the form of a water scavenger, a primary alcohol scavenger and a reactive amide- and / or amine-containing antifouling agent scavenger in an antifouling paint composition in the paint composition.

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