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EP-4735540-A1 - ANTIFOULING COMPOSITION

EP4735540A1EP 4735540 A1EP4735540 A1EP 4735540A1EP-4735540-A1

Abstract

The invention provides 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 in the (meth)acrylic silyl ester copolymer and/or (ii) a (meth)acrylic polymer 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 in the (meth)acrylic polymer; (iii) a monocarboxylic acid or a metal salt thereof; (iv) biocides comprising: a. tralopyril; 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; and (v) 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

Assignees

  • Jotun A/S

Dates

Publication Date
20260506
Application Date
20240628

Claims (17)

  1. 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 in the (meth)acrylic silyl ester copolymer and/or (ii) a (meth)acrylic polymer 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 in the (meth)acrylic polymer; (iii) a monocarboxylic acid or a metal salt thereof; (iv) biocides comprising: a. tralopyril; 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; and (v) at least 35 wt% of pigments, extenders and biocides combined, relative to the total weight of the coating composition as a whole.
  2. 2. The antifouling coating composition as claimed in claim 1, wherein said composition comprises a (meth)acrylic silyl ester copolymer (i) or both a (meth)acrylic silyl ester copolymer (i) and a (meth)acrylic polymer (ii).
  3. 3. 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.
  4. 4. The antifouling coating composition as claimed in any preceding claim, wherein the copper compound has a copper content of at least 45 wt%, preferably at least 50 wt%, especially metallic copper or copper(I) oxide.
  5. 5. The antifouling coating composition as claimed in any preceding claim, wherein tralopyril is present in an amount of 0. 1 to 5.0 wt%, relative to the total weight of the composition, preferably 0.2 to 3.0 wt%, more preferably 0.3 to 2.0 wt%, even more preferably 0.4 to 1.0 wt% and/or RECTIFIED SHEET (RULE 91) ISA/EP wherein the 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%, even more preferably 0.3 to 2.0 wt%, further preferred 0.3 to 1.0 wt%.
  6. 6. 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 R 1 is H or CH3; R 2 is each independently selected from C1-C10 hydrocarbyl groups preferably isopropyl; (b) one or more monomer(s) of formula (II) wherein R 4 is H or CH3, and R 5 is a C1-C20 hydrocarbyl substituent, preferably a Cl-10 alkyl substituent.
  7. 7. The antifouling coating composition as claimed in any preceding claim wherein the coating composition comprises a (meth)acrylic polymer (ii).
  8. 8. The antifouling coating composition as claimed in any preceding claim wherein the (meth)acrylic polymer (ii) is a (meth)acrylic polymer (ii-a) that has a Tg of less than 10 °C, further preferred less than 0 °C, such as less than -10 °C. RECTIFIED SHEET (RULE 91) ISA/EP
  9. 9. The antifouling coating composition as claimed in claim 8, wherein the (meth)acrylic copolymer (ii-a) comprises (a) (meth)acrylic acid and (b) one or more monomer(s) of formula (II) wherein R 4 is H or CH3, and R 5 is a C1-C20 hydrocarbyl substituent preferably a Cl-10 alkyl substituent, most preferably methyl, ethyl, n-propyl, n-butyl or 2-ethylhexyl.
  10. 10. The antifouling coating composition as claimed in any preceding claim, wherein the (meth)acrylic polymer (ii) is a (meth)acrylic polymer (ii-b) and has a glass transition temperature (Tg) of at least 10 °C.
  11. 11. The antifouling coating composition as claimed in claim 10 wherein the (meth)acrylic ester polymer (ii-b) comprises: (a) one or more monomer(s) of formula (II) wherein R 4 is H or CH3, and R 5 is a C1-C20 hydrocarbyl substituent preferably a Cl-10 alkyl substituent, most preferably methyl, ethyl, n-propyl, n-butyl or 2-ethylhexyl; and (b) one or more monomers of formula (VI) RECTIFIED SHEET (RULE 91) ISA/EP wherein R 11 is H or CH3, and R 12 is a C3-40 substituent, such as C3-C20 substituent, containing at least one oxygen or nitrogen atom, preferably at least one oxygen atom or R 12 represents a poly(alkylene glycol) group.
  12. 12. The antifouling coating composition as claimed in any preceding claim, wherein component (i) is present 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%; and/or wherein component (ii-a) is present in an amount of 0.5 to 12 wt%, relative to the total weight of the coating compositions as a whole, preferably 1.0 to 7.0 wt%; and/or component (ii-b) is present in an amount of 1.0 to 15 wt.% relative to the total coating composition as a whole, preferably 2.0 to 12 wt%; and wherein the monocarboxylic acid or metal salt thereof (iii) is present in an amount of 5.0 to 30 wt% based on the total weight of the coating composition as a whole, preferably 5.0 to 25 wt%.
  13. 13. The antifouling coating composition as claimed in any preceding claim, wherein the monocarboxylic acid or metal salt thereof (iii) is rosin, modified rosin or metal salts thereof, especially gum rosin, hydrogenated gum rosin, copper salt of gum rosin, zinc salt of gum rosin, copper salt of hydrogenated gum rosin, zinc salt of hydrogenated gum rosin and mixtures thereof.
  14. 14. 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.
  15. 15. The antifouling coating composition as claimed in any preceding claim, wherein tralopyril is present in an amount of 5.0 to 60.0 wt%, relative to the total weight of biocides (iv), preferably 7.0 to 60.0 wt%, more preferably 8.0 to 60.0 wt%, even more preferably 9.0 to 60.0 wt%, further preferred 10.0 to 60.0 wt% and/or wherein the one or more copper compounds is present in an amount of 5.0 to 90.0 wt%, relative to the total weight of biocides (iv), preferably 6.0 to 87.0 wt%, more preferably 7.0 to 85.0 wt%, even more preferably 8.0 to 82.0 wt%, further preferred 9.0 to 80.0 wt%. RECTIFIED SHEET (RULE 91) ISA/EP
  16. 16. 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 15.
  17. 17. An object coated with the antifouling coating composition as claimed in any of claims 1 to 15. RECTIFIED SHEET (RULE 91) ISA/EP

Description

Antifouling Composition 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 tralopyril and a copper compound having a copper content of at least 40 wt%. The compositions additionally contain a monocarboxylic acid or a metal salt thereof, a (meth)acrylic silyl ester copolymer and/or a (meth)acrylic polymer and pigments and/or extenders. 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 system 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 poly siloxane 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 redesigned. There thus remains a need to develop new self-polishing antifouling coating compositions which contain reduced levels of biocides. Tralopyril is a relatively new metal-free, organic marine antifouling agent which has a broad spectrum of activity against hard-shelled and soft-bodied invertebrates such as barnacles, hydroids, mussels, oysters, tube worms and tunicates. Tralopyril is sold under the trade name Econea and the supplier’s product datasheet recommend using between 4 and 6 wt% in antifouling coating compositions. When lower amounts of tralopyril are used as the only biocide active against hard fouling there is a challenge with achieving sufficient antifouling performance. The present inventors have surprisingly found that combining tralopyril 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. 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 present in the (meth)acrylic silyl ester copolymer; and/or (ii