EP-4735541-A1 - ANTIFOULING COMPOSITION

Abstract

An antifouling coating composition comprising: (i) a (meth)acrylic silyl ester copolymer comprising at least 15 wt% silyl ester monomers, relative to the total weight of monomers present in the (meth)acrylic silyl ester copolymer; and/or (ii) a (meth)acrylic copolymer comprising 10 wt% or less of silyl ester monomers and 5.0 wt% or less of metal ester monomers, relative to the total weight of monomers present in the (meth)acrylic copolymer, which has a Tg of 10.0 °C or more; (iii) rosin, modified rosin or a metal salt of rosin or a modified rosin; (iv) biocides comprising: a. medetomidine; and b. one or more copper compounds having a copper content of at least 40 wt%, relative to the formula weight of the copper compound, wherein the coating composition as a whole comprises 10.0 wt% or less of biocides; (v) a (meth)acrylic copolymer comprising 10 wt% or less of silyl ester monomers and 5.0 wt% or less of metal ester monomers, relative to the total weight of monomers present in the (meth)acrylic copolymer, which has a Tg below 10.0 °C, preferably below 0 °C, more preferred below - 5 °C, even more preferred below -10 °C, comprising a. monomer of formula (II) wherein R 4 is H or CH 3 , and R 5 is a C1-C20 hydrocarbyl substituent; and b. 0.5 to 10 wt% of at least one carboxylic acid containing monomer; and 102 (vi) at least 35 wt% of pigments, extenders and biocides combined, relative to the total weight of the coating composition as a whole.

Inventors

• DAHLING, MARIT
• Hanssen, Karoline
• Trondsen, Gaute

Assignees

• Jotun A/S

Dates

Publication Date

20260506

Application Date

20240628

Claims (1)

1. Claims 1. An antifouling coating composition comprising: (i) a (meth)acrylic silyl ester copolymer comprising at least 15 wt% silyl ester monomers, relative to the total weight of monomers present in the (meth)acrylic silyl ester copolymer; and/or (ii) a (meth)acrylic copolymer comprising 10 wt% or less of silyl ester monomers and 5.0 wt% or less of metal ester monomers, relative to the total weight of monomers present in the (meth)acrylic copolymer, which has a Tg of 10.0 °C or more; (iii) rosin, modified rosin or a metal salt of rosin or a modified rosin; (iv) biocides comprising: a. medetomidine; and b. one or more copper compounds having a copper content of at least 40 wt%, relative to the formula weight of the copper compound, wherein the coating composition as a whole comprises 10.0 wt% or less of biocides; (v) a (meth)acrylic copolymer comprising 10 wt% or less of silyl ester monomers and 5.0 wt% or less of metal ester monomers, relative to the total weight of monomers present in the (meth)acrylic copolymer, which has a Tg below 10.0 °C, preferably below 0 °C, more preferred below - 5 °C, even more preferred below -10 °C, comprising a. monomer of formula II: wherein R4 is H or CH3, and R5 is a C1-C20 hydrocarbyl substituent; and b. 0.5 to 10 wt% of at least one carboxylic acid containing monomer; and (vi) at least 35 wt% of pigments, extenders and biocides combined, relative to the total weight of the coating composition as a whole. 2. The antifouling coating composition as claimed in claim 1, wherein said composition comprises a (meth)acrylic silyl ester copolymer (i). 3. The antifouling coating composition as claimed in claim 1, wherein said composition comprises a (meth)acrylic copolymer (ii) or wherein said composition comprises a (meth)acrylic copolymer (ii) and a (meth)acrylic silyl ester copolymer (i). 4. The antifouling coating composition as claimed in any preceding claim, wherein the composition comprises 8.0 wt% or less of biocides, relative to the total weight of the coating composition as a whole, preferably 5.0 wt% or less. 5. The antifouling coating composition as claimed in any preceding claim, wherein the copper compound has a copper content of at least 50 wt%, such as copper (I) oxide. 6. The antifouling coating composition as claimed in any preceding claim, wherein medetomidine is present in an amount of 0.05 to 1.0 wt%, relative to the total weight of the composition, preferably 0.05 to 0.6 wt%, even more preferably 0.1 to 0.4 wt% and/or wherein the one or more copper compound is present in an amount of 0.1 to 8.0 wt%, relative to the total weight of the composition preferably 0.2 to 5.0 wt%, more preferably 0.3 to 3.0 wt%. 7. The antifouling coating composition as claimed in any preceding claim, wherein the (meth)acrylic silyl ester copolymer (i) comprises structural units derived from the following monomers: (a) a silyl ester monomer of formula (I), wherein R1 is H or CH 3 ; R2 is each independently selected from C1-C10 hydrocarbyl groups, preferably isopropyl; (b) one or more monomer(s) of formula (II) wherein R4 is H or CH 3 , and R5 is a C1-C20 hydrocarbyl substituent preferably a C1-10 alkyl substituent; and optionally (c) one or more monomers of formula (III) wherein R6 is H or CH3, and R7 is a C3-C20 substituent containing at least one oxygen or nitrogen atom, preferably at least one oxygen. 8. The antifouling coating composition as claimed in preceding claim, wherein the (meth)acrylic copolymer (v) comprises, such as consists of, (a) one or more monomer(s) of formula (II) wherein R4 is H or CH 3 , and R5 is a C1-C20 hydrocarbyl substituent, most preferably methyl, ethyl, n-propyl, n-butyl or 2-ethylhexyl and (b) (meth)acrylic acid 9. The antifouling coating composition as claimed in 8 wherein the monomer of formula (II) is methyl methacrylate, ethyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl methacrylate or isooctyl acrylate. 10. The antifouling coating composition as claimed in any preceding claim wherein the (meth)acrylic ester copolymer (ii) comprises such as consists of: (a) one or more monomer(s) of formula (II) wherein R4 is H or CH3, and R5 is a C1-C20 hydrocarbyl substituent preferably a C1-10 alkyl substituent, most preferably methyl, ethyl, n-propyl, n- butyl or 2-ethylhexyl; and (b) one or more monomers of formula (VI) wherein R11 is H or CH 3 , and R12 is a C3-20 substituent, such as C3-C10 substituent, containing at least one oxygen or nitrogen atom, preferably at least one oxygen atom or R12 represents a poly(alkylene glycol) group. 11. The antifouling coating composition as claimed in any preceding claim, wherein component (i) is present in an amount of 2.0 to 40 wt%, relative to the total weight of the coating compositions as a whole, preferably 5.0 to 30 wt%; and/or wherein component (v) is present in an amount of 0.5 to 10 wt%, relative to the total weight of the coating compositions as a whole, preferably 1.0 to 5.0 wt%; and/or wherein the rosin, modified rosin or metal salt thereof (iii) is present in an amount of 5.0 to 25 wt% based on the total weight of the coating composition as a whole. 12. The antifouling coating composition as claimed in any preceding claim, wherein compound (iii) is gum rosin, hydrogenated gum rosin, copper salt of gum rosin, zinc salt of gum rosin, zinc salt of hydrogenated gum rosin, copper salt of hydrogenated gum rosin and mixtures thereof. 13. The antifouling coating composition as claimed in any preceding claim, further comprising one or more biocides selected from zinc pyrithione, copper pyrithione, zineb and 4,5-dichloro-2-octyl-4-isothiazolin-3-one. 14. The antifouling coating composition as claimed in any preceding claim comprising: component (i) in an amount of 2.0 to 30 wt%, relative to the total weight of the coating compositions as a whole, preferably 5.0 to 25 wt%; component (v) in an amount of 0.5 to 10 wt%, relative to the total weight of the coating compositions as a whole, preferably 1.0 to 5.0 wt%; and component (iii) in an amount of 5.0 to 30 wt% based on the total weight of the coating composition as a whole; medetomidine in an amount of 0.05 to 1.0 wt%, relative to the total weight of the composition, preferably 0.05 to 0.7 wt%, more preferably 0.05 to 0.5 wt%, even more preferably 0.1 to 0.3 wt%; and one or more copper compounds in an amount of 0.1 to 8.0 wt%, relative to the total weight of the composition preferably 0.2 to 5.0 wt%, more preferably 0.3 to 3.0 wt%; or component (ii) in an amount of 2.0 to 30 wt%, relative to the total weight of the coating compositions as a whole, preferably 5.0 to 25 wt%; component (v) in an amount of 0.5 to 10 wt%, relative to the total weight of the coating compositions as a whole, preferably 1.0 to 5.0 wt%; component (iii) in an amount of 5.0 to 30 wt% based on the total weight of the coating composition as a whole; medetomidine in an amount of 0.05 to 1.0 wt%, relative to the total weight of the composition, preferably 0.05 to 0.7 wt%, more preferably 0.05 to 0.5 wt%, even more preferably 0.1 to 0.3 wt%; and one or more copper compounds is present in an amount of 0.1 to 8.0 wt%, relative to the total weight of the composition preferably 0.2 to 5.0 wt%, more preferably 0.3 to 3.0 wt%; wherein the antifouling coating composition comprises pigments and/or extenders and the combined total of pigments, extenders and biocides is 35 wt% or more. 15 A process for protecting an object from fouling, said process comprising coating at least a part of said object which is subject to fouling with an antifouling coating composition as claimed in any of claims 1 to 14. 16. An object coated with the antifouling coating composition as claimed in any of claims 1 to 14.

Description

P2309 Antifouling Composition 166981/01 Field of the Invention The present invention relates to marine antifouling coating compositions, more specifically to antifouling coating compositions comprising biocides in an amount of 10.0 wt% or less, wherein the biocides comprise medetomidine and a copper compound having a copper content of at least 40 wt%. The compositions additionally contain a rosin, a modified rosin or metal salts thereof, and a specific (meth)acrylic copolymer. The invention further relates to a method of protecting objects from fouling, and to objects coated with the antifouling composition of the invention. Background of invention Surfaces that are submerged in seawater are subjected to fouling by marine organisms such as green and brown algae, barnacles, mussels, tube worms and the like. On marine constructions such as vessels, oil platforms, buoys, etc. such fouling is undesired and has economic consequences. The fouling may lead to biological degradation of the surface, increased load and accelerated corrosion. On vessels the fouling will increase the frictional resistance which will cause reduced speed and/or increased fuel consumption. To prevent settlement and growth of marine organisms, antifouling paints are used. These paints generally comprise a film-forming binder, together with different components such as pigments, extenders, additives and solvents together with biologically active substances (biocides). Biocides can be broadly divided into those active against soft fouling, such as green and brown algae, grass, slime and those active against hard fouling, such as barnacles, mussels, tube worms etc. The largest product segment for antifouling coating systems on merchant vessels is self-polishing antifouling coatings (SPC). The majority of the products are copper based with a relatively high total content of biocides, pigments and extenders. The commercial copper containing products typically contain 20-50 % by weight of copper(I) oxide, which is known to have good activity against hard fouling, and an additional 1-10 % by weight of organic biocides, which are mainly active against soft fouling, to broaden the antifouling activity spectrum of the products. One of the success factors with SPC products is that the polishing rate can be adjusted to maximise their effectiveness on vessels with different operational speeds and activity. There is a limited number of biocides approved for use as marine antifouling agents by regulatory bodies. The approved biocides are considered safe to use and without adverse environmental effects. However, it is still important to optimize the effect of the combination of biocides in the coating film to limit their use to a minimum. Restrictions on the use of biocides are increasing and it is likely that in the future the amounts of biocides in antifouling coatings will have to be significantly reduced. When reducing the amounts of biocides there is a challenge in maintaining good long term antifouling performance. Low biocide formulations are generally associated with formulations having a low content of pigments and extenders often in combination with polysiloxane binders or binders having polysiloxane blocks and/or added silicone oils. An example of commercial products are biocidal fouling release coatings (FRC). Reducing the biocide to low levels in conventional self-polishing antifouling coatings will require a full or part replacement of biocides by other components. That will have consequences for the self-polishing properties, mechanical properties and antifouling performance of the coating, unless the formulation is carefully re- designed. There thus remains a need to develop new self-polishing antifouling coating compositions which contain reduced levels of biocides. Medetomidine is an organic biocide which has specific actions against hard fouling, and in particular barnacle cyprids. Medetomidine is sold under the trade name Selektope and the supplier’s product datasheet recommend using between 0.1 and 0.3 wt% in combination with an algicide in antifouling coating compositions in order to obtain full protection against marine fouling. When medetomidine is used as the only biocide active against hard fouling there is a challenge with achieving sufficient antifouling performance due to its specific biological activity. The present inventors have surprisingly found that combining medetomidine with a copper compound as defined herein, self-polishing antifouling coating compositions with 10 wt% or less total biocides can be prepared. Such coating compositions have unexpectedly attractive antifouling properties despite the low levels of biocides, in particular the low amounts of copper compounds present. Summary of invention In one aspect, the invention relates to an antifouling coating composition comprising: (i) a (meth)acrylic silyl ester copolymer comprising at least 15 wt% silyl ester monomers, relative to the total weight of monomers