An Erodible Antifouling Coating Composition

Abstract

An erodible antifouling coating composition for application, for example,to ship's hulls to potentially prevent the adhesion and build up of fouling agents on the hull is described. The coating composition comprises an erodible binder system excluding a triorgano tin based binder; optionally, one or more antifouling agents; and at least one silicone oil. A process for producing the composition, a substrate coated with the composition, and a process of coating a substrate with the composition are also described.

Claims

1. An erodible antifouling coating composition comprising: an erodible binder system excluding a triorgano tin based binder; optionally, one or more antifouling agents; and at least one silicone oil.

2. An erodible antifouling coating composition according to claim 1, wherein the silicone oil comprises a polydiorganosiloxane such as an alkyl and/or aryl substituted polysiloxane.

3. An erodible antifouling coating composition according to any preceding claim, wherein the composition comprises a mixture of silicone oils differing in molecular weight and/or in the nature of the groups bonded to the silicon atoms.

4. An erodible antifouling coating composition according to any preceding claim, wherein the silicone oil comprises a polyorganosiloxane having a structure comprising diorganosiloxane residues and terminal organosiloxane residues, and, optionally, branch organosiloxane residues; wherein the diorganosiloxane residues of the polyorganosiloxane comprise one or more of ##STR00012## and; the terminal organosiloxane residues comprise ##STR00013## whereas the optional branch organosiloxane residues comprise; ##STR00014## wherein R.sup.1 to R.sup.6 independently comprise an inert optionally substituted organic group such as C.sub.1-8 alkyl or aryl, generally, methyl or phenyl; R.sup.7 comprises an inert optionally substituted organic group such as aryl, generally phenyl; R.sup.8 comprises an inert optionally substituted organic group such as C.sub.1-8alkyl, generally, methyl or ethyl, optionally, methyl; v=n+2m+1; w=1; n is 0 to x+y+z/3, generally 0 to x+y+z/10, such as 0 to x+y+z/50, rounded to the nearest whole number; m is 0 to x+y+z/10,generally0 to x+y+z/50,such as0 to x+y+z/100, rounded to the nearest whole number; x+y+z is 5 to 1000, generally 10 to 500, such as 20 to 200, with the proviso that diorganosiloxane residues selected from the structures in (i) above having R.sup.7 groups and diorganosiloxane residues selected from the structures in (i) above having R.sup.8 groups are present in the polyorganosiloxane.

5. An erodible antifouling coating composition according to claim 4 wherein each of the R.sup.1 to R.sup.6 groups independently comprise alkyl and aryl groups, R.sup.7 comprises an aryl group and R.sup.8 comprises an alkyl group, more typically, each of the R.sup.1 to R.sup.6 groups independently comprise methyl and phenyl groups, R.sup.7 comprises a phenyl group and R.sup.8 comprises a methyl group.

6. An erodible antifouling coating composition according to any of claims 2-5, wherein the alkyl groups comprise saturated hydrocarbon radicals being straight or branched, polycyclic, acyclic, cyclic or part cyclic/acyclic moieties or combinations thereof and contain 1 to 10 carbon atoms, such as 1 to 8 carbon atoms, for example 1 to 6 carbon atoms, or 1 to 4 carbon atoms, or are selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl and cyclic or branched variants thereof, n-hexyl and cyclic or branched variants thereof, n-heptyl and cyclic or branched variants thereof and n-octyl and cyclic or branched variants thereof, more typically, from the group methyl, ethyl, n-propyl isopropyl and most typically, from methyl; and/or wherein the aryl groups are an organic radical derived from an aromatic hydrocarbon by removal of one hydrogen and include any monocyclic, bicyclic or polycyclic carbon ring of up to 7 members in each ring, wherein at least one ring is aromatic and more typically, wherein the aryl group is selected from such monocyclic and bicyclic rings, wherein said radical may be optionally substituted with one or more substituents independently selected from alkyl or alkoxy radicals, and/or wherein, the aryl groups are generally selected from phenyl, naphthyl, idenyl and alkyl substituted phenyl, more typically, methyl substituted phenyl and phenyl, most typically, phenyl.

7. An erodible antifouling coating composition according to any of claims 4 to 6, wherein at least 10% of the total R.sup.7 and R.sup.8 groups are alkyl and at least 10% of total R.sup.7 and R.sup.8 groups are aryl, such as at least 30% of total R.sup.7 and R.sup.8 groups being alkyl and at least 10% of total R.sup.7 and R.sup.8 groups being aryl or, wherein R.sup.1 to R.sup.6 each independently comprise methyl and/or phenyl, typically, at least some of R.sup.8 groups are methyl and some of R.sup.7 groups are phenyl, more typically, at least 10% of the R.sup.8 groups are methyl and at least 10% of R.sup.7 groups are phenyl, most typically, at least 30% of R.sup.8 groups are methyl and at least 10% of R.sup.7 groups are phenyl.

8. An erodible antifouling coating composition according to any preceding claim wherein the silicone oil is a methyl phenyl silicone oil in which, optionally, at least 25% of the diorganosiloxane units are methylphenylsiloxane units and optionally, the silicone oil is a trimethylsilyl-terminated poly(methylphenylsiloxane).

9. An erodible antifouling coating composition according to any preceding claim, wherein the composition comprises at least a first and a second silicone oil wherein optionally, the first silicone oil comprises alkyl and aryl organo groups attached to silicon in the siloxane in a first ratio, and the second silicone oil comprises alkyl and aryl organo groups in a second ratio, wherein optionally, the first ratio and the second ratio are different and/or optionally, the total organo groups of the first silicone oil comprise alkyl groups in the proportion of 70% to 95%, such as 80% to 90%, and/or aryl groups in the proportion of 5% to 30%, for example 10 to 20%, and/or optionally, the total organo groups of the second silicone oil comprise alkyl groups in the proportion of 50% to 80%, such as 60% to 70%, and/or aryl groups in the range of 20% to 50% total groups, for example 30% to 40%, and/or optionally, the first silicone oil and the second silicone oil are contained in the antifouling composition in a ratio of between 10:1 to 1:10 by weight, such as in a ratio of between 10:1 and 1:2 by weight, for example in a ratio of between 10:2 and 1:1, or in a ratio of between 10:5 and 10:8, such as in a ratio of between 10:6 and 10:7.5 by weight.

10. An erodible antifouling coating composition according to any preceding claim, wherein the silicone oil includes 510V100 and/or 550 silicone oil.

11. An erodible antifouling coating composition according to any preceding claim, wherein the erodible binder system is self-polishing and/or ablative.

12. An erodible antifouling coating composition according to any preceding claim, wherein the erodible binder system is based on an effective amount of alkaline soluble binder.

13. An erodible antifouling coating composition according to any preceding claim, wherein the erosion rate of the dried coating on a substrate in seawater is at least 1 m per month at 10 knots.

14. An erodible antifouling coating composition according to claim 12 or 13, wherein the alkaline soluble binder optionally comprises a rosin based binder, a zinc resinate based binder, a copper resinate based binder, a silyl acrylate based binder or a metal (such as copper, zinc, magnesium or calcium) acrylate based binder including copolymers and/or mixtures thereof, such as, an alkaline soluble binder comprising a zinc acrylate based binder, a copper acrylate based binder, a silyl acrylate based binder and/or a silyl acrylate/zinc acrylate based copolymer binder.

15. An erodible antifouling coating composition according to claim 14, wherein the rosin based binder comprises a resin acid, typically, a polycyclic monocarboxylic acid such as abietic acid and/or metal resinates such as copper, calcium, magnesium or zinc resinates; and/or wherein the silyl acrylate based binder is a binder comprising residues of monomers in accordance with formula I: ##STR00015## wherein R.sup.31, R.sup.32, R.sup.33, R.sup.34, R.sup.35 each independently comprise an alkyl, an aryl group or a hydrogen atom, R.sup.36 comprises a hydrogen atom or a methyl group, R.sup.37 comprises a hydrogen atom or an alkyl group, typically, hydrogen, n represents a number of diorganosilxoane units from 0 to 200, for example homo- or copolymers of triisopropylsilyl (meth)acrylate (TIPSA), or tri-t-butylsilyl(meth)acrylate with optionally one or more suitable comonomers or mixtures thereof; and/or the metal acrylate based binder comprises an acrylic copolymer having at least one side chain bearing a group of the formula II ##STR00016## wherein M comprises Zn, Ca, Mg or Cu, more typically, Zn or Cu and R.sup.40 represents an organic acid residue selected from ##STR00017## wherein R.sup.41 is a monovalent organic residue.

16. An erodible antifouling coating composition according to claim 15, wherein R.sup.31, R.sup.32, R.sup.33, R.sup.34, R.sup.35 each independently represent an alkyl, an aryl group or a hydrogen atom, R.sup.36 represents a hydrogen atom or a methyl group, and R.sup.37 represents a hydrogen atom or an alkyl group, typically, hydrogen.

17. An erodible antifouling coating composition according to any preceding claim, wherein the amount of erodible binder system in the composition is generally between 1% to 80% by weight of the solid content in the antifouling coating, the amount present may be 10% to 60% by weight solids.

18. An erodible antifouling coating composition according to any preceding claim, wherein the binder system comprises either a copolymer and/or a co-binder (co)polymer and in either case typically incorporates (co)monomer residues such as acrylic and/or vinyl monomer residues.

19. An erodible antifouling coating composition according to any preceding claim, wherein the antifouling agent is generally a biocidal agent used as a component in the coating composition of the present invention and may be any of one or more conventionally known antifoulants, optionally selected from inorganic compounds, metal-containing organic compounds, and metal-free organic compounds.

20. A substrate at least partially coated with a dried coating composition according to any preceding claim, and wherein the substrate is an optionally primer coated and/or optionally intermediate and/or otherwise suitably coated metal substrate, such as an underwater structure, for example, the surface of a ship's hull whether uncoated, primer and/or intermediate and/or otherwise suitably coated.

21. A process for producing an erodible antifouling coating composition according to any of claims 1 to 19, wherein the coating composition is prepared by combining the erodible binder system, silicone oil(s), a solvent and optionally any other conventional components such as co-binder resins, a biocidal agent, a pigment, a plasticizer, a coating-abrasion regulator, etc. and then mixing them by a suitable method such as mixing for example by a ball mill, a pebble mill, a roll mill or a sand grind mill.

22. A process of coating at least a portion of a substrate with an erodible antifouling coating according to any of claims 1-19 by applying the undried antifouling coating composition onto the surface of a leach layer free substrate to be coated and then removing the solvent through evaporation at ordinary temperature or under heating wherein the leach layer free substrate may be a metal substrate, a primer layer, an intermediate layer or a previous erodible antifouling coating and wherein when over-coating with an erodible antifouling coating composition according to any of claims 1 to 18, the old coating is washed and/or sweep blasted such that whatever leach layer is present, if any, is removed before over-coating with the new over-coating layer.

Description

EXAMPLES

[0134] The invention will be further discussed with reference to the following non-limiting examples.

[0135] In the examples, the following test methods were employed:

Test Methods

[0136] Stability at 40 C. [0137] The stability of the viscosity of the paint samples was monitored at 40 C. for 1 year. The viscosity was determined every three months.

[0138] Polishing [0139] The paint formulations were sprayed on discs. These discs were rotated in seawater. Before the start of the rotation, the layer thickness of the paint samples on the discs was measured. The decrease in layer thickness (polishing) was then measured every ten weeks.

[0140] Static Raft Performance [0141] Paint formulations were sprayed on panels. These panels were exposed in seawater in different marine locations. Quarterly pictures were taken and the static raft performance was judged on slime, soft fouling and hard fouling.

[0142] Boottop performance [0143] Paint formulations are sprayed on panels. Panels are exposed to seawater and every ten weeks the panels are taken out of the water and exposed on an exposition field outside. Panels are judged every 10 weeks on physical properties-blisters, cracking and detachment.

[0144] Drag/torque measurements [0145] Paint formulations are sprayed on discs. Discs are rotated in a container filled with seawater. The torque of the rotating disks is measured at various speeds and at various times.

[0146] Particle size is determined with a fineness gauge: a small amount of paint is placed in the deep end of the groove of a fineness gauge. With a straight edge scraper the paint is drawn towards the shallow end of the groove. Fineness indication of the paint is at the point of the scale where the oversized particles appear in a substantial concentration.

[0147] Dispersing is generally done by means of a dissolver at high speed.

Experimental

Example 1

[0148]

TABLE-US-00001 Rosin based AF Raw Material Amount [kg] Lutonal A25 1.40 Rosin 16.65 Byk 065 0.39 Rhodorsil oil 550 1.10 Rhodorsil oil 510V100 1.48 Seanine 211 7.38 Bayferrox 222FM 8.85 Disparlon 6650 0.51 ZnO indirect Serena 23.83 Finntalc M40 12.38 Econea 028 3.51 Bentone SD-2 1.15 Xylene 21.37 Total 100.00 Key:- Lutonal A25 Plasticiser Byk 065 Defoamer Rhodorsil oil 510 V 100/Dow Methyl phenyl polysiloxane Corning 51 oil Rhodorsil oil 550/Dow Corning Methyl phenyl polysiloxane 550 oil Sea-Nine 211 Isothiazolinone based antifoulant Bayferrox 222 FM Iron Oxide Pigment Disparlon 6650 Thixotropic Agent Finntalc M40 Talc Filler Econea 028 Biocidal Agent Bentone SD-2 Thixotropic Agent

[0149] Binder (rosin) is dissolved in solvent (xylene/seanine) and when the binder is dissolved, plasticizer (lutonal) and defoamer (BYK 065) are added. Thixotropic agents (Disparlon and Bentone) are added and activated by dispersing for 15 minutes. All the pigments and biocidal agent (ZnO, Finntalc, Econea Bayferrox) are then added and the mixture is dispersed until a particle size fineness of 45-50 m and a temperature of up to 60 C. is reached. Release oils (oil 550 and 510V100) are then added and viscosity of final paint is adjusted with solvent.

Example 2

[0150]

TABLE-US-00002 Silylacrylate based AF Raw Material Amount [kg] Polyace NSP100 20.19 Vestinol AH 1.77 Thixatrol ST 0.97 Rosin 4.60 Rhodorsil oil 550 2.36 Rhodorsil oil 510V100 1.29 Seanine 211 6.05 Cuprous oxide 40.51 Bayferrox 222 FM 4.73 ZnO direct EMP 9.51 Sylosive A4 1.26 Finntalc M40 1.18 xylene 5.57 Total 100.00 Key:- Polyace NSP-100 Silyl acrylate binder Vestinol AH Plasticiser Thixatrol ST Thixotropic Agent Zinc oxide Direct EMP ZnO Filler Sylosive A4 dehydrator

[0151] Binder (rosin) is dissolved in solvent (xylene/seanine). When binder is dissolved, plasticizer (Vestinol AH) and binder (Polyace) are added. Thix agent (Thixatrol) and water scavenger (Sylosiv A4) are added and activated by dispersing for 15 minutes. All pigments (ZnO, Bayferrox and Cu.sub.2O) are added and the mixture is ground until a particle size fineness of 45-50 m (grinding is done by means of a bead-mill) and temperature of max. 60 C. is reached. Release oils (oil 550 and 510V100) are added and viscosity of final paint is set with solvent.

Example 3

[0152]

TABLE-US-00003 Silylacrylate based AF Raw Material Amount [kg] Polyace NSP-100, 19.990 Lankroflex E2307/Dehysol D 81, 1.780 Sea-Nine 211 6.00 Indonesian Gum Rosin 4.56 Disparlon A603-20X 4.67 Sylosiv A4 1.25 Bayferrox 222 FM 4.70 Cuprous oxide, Red 40.12 Zinc oxide Direct EMP 9.42 Finntalc M40 1.17 Xylene 4.09 Rhodorsil oil 510 V 100/Dow Corning 51 1.29 Rhodorsil oil 550/Dow Corning 550 0.960 Key:- Lankroflex E2307/Dehysol D 81 Plasticiser Indonesian Gum Rosin Binder self polishing Cuprous oxide, Red Biocidal Agent Disparlon A603-20X Polyamide wax

[0153] Binder (rosin) is dissolved in solvent (xylene/seanine) when binder is solved; plasticizer (lankroflexl) and binder Polyace are added. Water scavenger (sylosive) and thix agent (disparlon) are added and dispersed. All pigments (ZnO, Finntalc, Bayferrox and Cu.sub.2O) are added and the mixture is ground until a particle size fineness of 45-50 m and temperature of max. 60 C. is reached. Release oils (oil 550 and 510V100) are added and viscosity of final paint is set with solvent.

Preparative Example 4

[0154]

TABLE-US-00004 Zinc acrylate based AF Raw Material Amount [Kg] Dianal MR-9393 (Zinc Acrylate self 48.55 polishing binder) Rhodorsil oil 550 1.16 Rhodorsil oil 510V100 2.12 Blanc fixe 16.01 Finntalc M15 5.67 Zinc Omadine 7.35 Econea 028 4.71 Bayferrox 130 BM 6.01 Disparlon A603-20X 5.01 Xylene 3.41 Total 100.00 Key:- Dianal MR-9393 Zinc Acrylate self polishing binder Blanc fixe Filler Finntalc M15 Talc Filler Zinc Omadine Biocidal Agent Bayferrox 130 BM Iron Oxide Pigment

[0155] To binder (Dianal MR9393), pigments (blanc fixe, finntalc, zinc omadine, econea and bayferrox) and thix agent (Disparlon) are added and the mixture is ground until a particle size fineness of 45-50 m and temperature of max. 60 C. is reached. Release oils (oil 550 and 510V100) are added and viscosity of final paint is set with xylene.

[0156] Results

TABLE-US-00005 TABLE 1 results for examples 1, 2 and 3 Example 1 Example 2 Example 3 Stability 1 year 25.9 19.5 22.1 @40 C. in [mPas .Math. s] Polishing 6.6 m/month 2.20 m/month 1.87 m/month Static raft 0% barnacles 0% barnacles 0% barnacles performance <10% algae <10% algae <10% algae Mediterranean Boottop No defects No defects No defects performance Draq torque Less drag than measurements without release oils

[0157] Oil Combinations Tested

[0158] Example 1 and 2 formulations were also tested and compared with single release oils DC 3074a methoxyfunctional silicone intermediate, Rhodorsil oil 510V100 and Rhodorsil oil 550.

TABLE-US-00006 TABLE 2 results for example 1 (rosin based) with different oils Comparative Example 1 Example 6 Comparative Example 1 Example 5 Example 1 Example 2 Without Example 1 with oil Example 1 Example 1 silicone oil with oil 550 510V100 with both oils with DC3074 Stability after 1 15.7 24.1 28.2 25.9 23.7 year @ 40 C. in [mPas.s] Static raft 3-10% 0% barnacles 1-3% 0% barnacles 10-20% performance barnacles and <10% barnacles and <10% barnacles Mediterranean and <10% algae and <10% algae and <10% algae algae algae

TABLE-US-00007 TABLE 3 Stability results for example 2 (silyl acrylate based) with different oils Compar- Compar- ative Example Example Example ative Example 3- 7- 8- 2 Example 4- Example 2 Example 2 Example 2 with Example 2 Without With oil with oil both with silicone oil 550 510V100 oils DC3074 Stability 24.2 21.0 26.1 19.5 >100 after 1 year @ 40 C. in [mPas .Math. s]

[0159] Stability of paint products is measured as viscosity and should not exceed 40 mPas.s at 40 C. after 1 year

[0160] In addition, drag torque measurements indicated that comparative example 3 without silicone oil had more drag than example 2 with both oils which decreased by 11.5% over time.

Drag Torque Measurements

[0161] At 1, 6, 12 and 18 months torque measurements were done on rotating discs.

[0162] Torque was measured in Nm

Comparative Example 1

[0163] Rosin based AF

[0164] Example 1 was repeated but without silicon oils.

TABLE-US-00008 Comparative Example 1 Example 1 Raw Material Amount [kg] Amount [kg] Lutonal A25 1.40 1.3 Rosin 16.65 17.93 Byk 065 0.39 0.36 Rhodorsil oil 550 1.10 Rhodorsil oil 510V100 1.48 Seanine 211 7.38 6.85 Bayferrox 222FM 8.85 8.22 Disparlon 6650 0.51 0.47 ZnO indirect Serena 23.83 25.51 Finntalc M40 12.38 9.8 Econea 028 3.51 3.26 Bentone SD-2 1.15 1.07 Xylene 21.37 25.21 Total 100.00 100.00

[0165] The results of example 1 versus comparative example 1 show a marked improvement in antifouling performancesee table 2 owing to the presence of the silicon oils in example 1.

Example 2 and Comparative Example 3

[0166] Silylacrylate based AF

TABLE-US-00009 Comparative Example 2 Example 3 Raw Material Amount [kg] Amount [kg] Polyace NSP100 20.19 21.64 Vestinol AH 1.77 1.70 Seanine 211N 6.05 5.80 Indonesian Rosin 4.60 5.53 Thixatrol ST 0.97 0.92 Sylosiv A4 1.26 1.21 Bayferrox 222 FM 4.73 4.54 Cuprous oxide, red 40.52 38.83 ZnO direct EMP 9.51 11.42 Finntalc M40 1.18 xylene 5.57 8.41 Rhodorsil oil 550 1.29 Rhodorsil oil 510V100 2.36 Total 100.00 100.0
The results of example 2 versus comparative example 3 show a marked improvement in drag torque of 11.5% over time.

[0167] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0168] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0169] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0170] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.