Antifouling coating composition, antifouling coating film, antifouling substrate, and method for improving storage stability of antifouling coating compositions

Abstract

In one aspect, the invention has an object of providing antifouling coating compositions which have high resistance to fouling, in particular, fouling by slime, can form coating films with excellent properties such as strength and rubber properties, exhibit appropriate viscosity (sprayability and coating film surface leveling properties during spray coating) and sagging resistance, and have high storage stability suppressing deteriorations of these properties. To achieve the object, the invention provides an antifouling coating composition including (A) a diorganopolysiloxane having at least two silanol groups in the molecule, (B) an organosilane and/or a partial hydrolyzate condensate thereof having at least two hydrolyzable groups in the molecule, and (C) a pyrithione metal salt. The antifouling coating composition can be prepared from a kit in the form of a multiple-component system including respective packages of a component including the component (A) and the component (C), and a component including the component (B). In the (kit for the preparation of the) antifouling coating composition, the pyrithione metal salt (C) functions as an effective ingredient for achieving excellent antifouling properties, in particular, anti-sliming properties, and also as an effective ingredient for improving storage stability.

Claims

1. An antifouling coating composition comprising: (A) a diorganopolysiloxane having at least two silanol groups in the molecule, (B) an organosilane and/or a partial hydrolyzate condensate thereof having at least two hydrolyzable groups in the molecule, and (C) a pyrithione metal salt, wherein the content of said pyrithione metal salt in said antifouling coating composition ranges from 3 to 20 wt %, and an ether-modified organopolysiloxane.

2. The antifouling coating composition according to claim 1, wherein the diorganopolysiloxane (A) is represented by General Formula [I]: ##STR00005## wherein R.sup.1 indicates independently at each occurrence a hydrocarbon group of 1 to 6 carbon atoms, the letter a is an integer of 1 to 3, and the letter n is an integer of 5 to 1,000.

3. The antifouling coating composition according to claim 1, wherein the organosilane and/or the partial hydrolyzate condensate thereof (B) is represented by General Formula [II]:
R.sup.2.sub.dSiY.sub.4-d  [II] wherein R.sup.2 indicates independently at each occurrence a hydrocarbon group of 1 to 6 carbon atoms, Y indicates independently at each occurrence a hydrolyzable group, and the letter d is an integer of 0 to 2.

4. The antifouling coating composition according to claim 1, wherein the pyrithione metal salt (C) is represented by General Formula [III]: ##STR00006## wherein R.sup.3 indicates independently at each occurrence a hydrogen atom or an alkyl, cycloalkyl, alkenyl, aryl, alkoxy or halogenated alkyl group of 1 to 6 carbon atoms, M indicates a metal Zn, Cu, Na, Mg, Ca, Ba, Fe or Sr, and the letter n is the valence of the metal M.

5. The antifouling coating composition according to claim 1, wherein the diorganopolysiloxane (A) has a weight average molecular weight of 500 to 1,000,000.

6. The antifouling coating composition according to claim 1, further comprising silica wherein silica and part or the whole of the diorganopolysiloxane (A) have been heat treated prior to preparing said antifouling coating composition.

7. The antifouling coating composition according to claim 1, wherein the organosilane and/or the partial hydrolyzate condensate thereof (B) has at least one of oxime groups, acetyloxy groups and alkoxy groups as the hydrolyzable groups.

8. The antifouling coating composition according to claim 1, further comprising a curing catalyst (G).

9. A kit for the preparation of the antifouling coating composition according to claim 1, the kit being a multiple-component system comprising respective packages of a component comprising the diorganopolysiloxane (A) and the pyrithione metal salt (C), and a component comprising the organosilane and/or the partial hydrolyzate condensate thereof (B).

10. An antifouling coating film obtained by curing the antifouling coating composition according to claim 1.

11. An antifouling substrate obtained by coating or impregnating a substrate with the antifouling coating composition according to claim 1, and thereafter curing the composition.

12. The antifouling substrate according to claim 11, wherein the substrate is an underwater structure or a marine vessel.

13. A method for manufacturing an antifouling substrate, comprising coating or impregnating a substrate with the antifouling coating composition according to claim 1, and curing the composition that has been applied to coat or impregnate the substrate.

14. The kit according to claim 9, further comprising silica wherein silica in a package and part or the whole of the diorganopolysiloxane (A) have been heat treated prior to being placed in said respective packages.

15. The antifouling coating composition according to claim 1, further comprising a phenyl-modified organopolysiloxane.

16. The antifouling coating composition according to claim 1, wherein the content of the ether-modified organopolysiloxan ranges 0.1 to 3 wt % in terms of the content in a dry coating film formed from the antifouling coating composition.

Description

DESCRIPTION OF EMBODIMENTS

(1) Hereinbelow, the present invention will be described in detail with respect to aspects such as antifouling coating compositions, antifouling coating films, antifouling substrates and methods for improving the storage stability of antifouling coating compositions. The present invention is not limited to embodiments described below, and various modifications are possible within the scope and spirit of the invention.

(2) —Antifouling Coating Compositions—

(3) An antifouling coating composition according to the present invention includes a diorganopolysiloxane (A) having at least two silanol groups (≡Si—OH) in the molecule, an organosilane and/or a partial hydrolyzate condensate thereof (B) having at least two hydrolyzable groups in the molecule, and a pyrithione metal salt (C). These components will be described sequentially below.

(4) (A) Diorganopolysiloxanes

(5) The diorganopolysiloxane (A) has at least two silanol groups in the molecule. In detail, compounds represented by General Formula [I] below are preferable.

(6) ##STR00003##

(7) In General Formula [I], R.sup.1 indicates independently at each occurrence a hydrocarbon group of 1 to 6 carbon atoms, for example, a linear or branched alkyl group such as methyl, ethyl or propyl group, or a cycloalkyl group such as cyclohexyl group, and is preferably a methyl group.

(8) The letter a is an integer of 1 to 3, and is preferably 1. The letter n is an integer of 5 or greater, and is preferably 100 to 1,000.

(9) The diorganopolysiloxane (A) preferably has a weight average molecular weight of 5 to 1,000,000, more preferably 5,000 to 100,000, and still more preferably 10,000 to 50,000. Further, the viscosity thereof at 23° C. is preferably 20 to 100,000 mPa.Math.s, more preferably 100 to 10,000 mPa.Math.s, and still more preferably 500 to 5,000 mPa.Math.s. These weight average molecular weight and viscosity values advantageously ensure that the coating exhibits excellent workability during production, sprayability and curability into coating films as well as that the resultant coating films show high strength.

(10) In the antifouling coating composition which may include a solvent, the diorganopolysiloxane (A) is usually present in 20 to 90 wt %, and preferably 50 to 70 wt %. Further, the content of the diorganopolysiloxane (A) with respect to 100 wt % of the solid content of the antifouling coating composition is usually 30 to 95 wt %, and preferably 60 to 90 wt %. Such a content ensures that coating films with good coating film strength and rubber elasticity can be formed as well as that the resultant antifouling coating films will exhibit antifouling properties for long periods.

(11) Commercially available products may be used as the diorganopolysiloxanes (A). Examples thereof include “DMS-S35” (manufactured by GELEST, Inc.).

(12) (Silica)

(13) The antifouling coating composition of the invention may contain silica together with the diorganopolysiloxane (A). In this case, the silica may be kneaded together with the diorganopolysiloxane (A) before use, in particular, during the preparation of a component including the diorganopolysiloxane (a main component) of a multiple-component antifouling coating composition.

(14) Examples of the silica for use in the invention include hydrophilic silica (non-surface-treated silica) such as wet process silica (hydrated silica) and dry process silica (fumed silica and anhydrous silica), and surface-treated hydrophobic silica such as hydrophobic wet silica and hydrophobic fumed silica. These types of silica may be used singly or as a mixture.

(15) The wet process silica is not particularly limited. For example, that having an adsorbed water content of about 4 to 8%, a bulk density of 200 to 300 g/L, a primary particle diameter of 10 to 30 μm and a specific surface area (a BET surface area) of not less than 10 m.sup.2/g may be used.

(16) The dry process silica is not particularly limited. For example, that having a water content of not more than 1.5%, a bulk density of 50 to 100 g/L, a primary particle diameter of 8 to 20 μm and a specific surface area of not less than 10 m.sup.2/g may be used.

(17) The hydrophobic fumed silica is obtained by surface-treating the dry process silica with organosilicon compounds such as methyltrichlorosilane, dimethyldichlorosilane, hexamethyldisilazane, hexamethylcyclotrisiloxane and octamethylcyclotetrasiloxane. The hydrophobic fumed silica absorbs little water over time, and the water content is usually not more than 0.3%, and most often 0.1 to 0.2%. The hydrophobic fumed silica is not particularly limited. For example, that having a primary particle diameter of 5 to 50 μm, a bulk density of 50 to 100 g/L, and a specific surface area of not less than 10 m.sup.2/g may be used.

(18) When the silica is heat treated together with the diorganopolysiloxane as will be described later, water adsorbed on the surface of the silica is physically reduced or removed. As a result, the water content of the heat-treated hydrophobic fumed silica is usually not more than 0.2%, preferably not more than 0.1%, and more preferably 0.05 to 0.1%. Other properties such as the bulk density remain the same as in the hydrophobic silica prior to the heat treatment.

(19) Commercially available products may be used as the silica. Examples thereof include “R974” and “RX200” manufactured by Nippon Aerosil Co., Ltd.

(20) When an antifouling coating composition is produced which contains the silica together with the diorganopolysiloxane, in particular, when a multiple-component antifouling coating composition is produced which includes a component (a main component) containing the diorganopolysiloxane kneaded together with the silica, the diorganopolysiloxane and the silica are preferably used as a heat-treated product formed by heat treating these components in advance, or as a mixture of the heat-treated product with the raw diorganopolysiloxane. Such a configuration is preferable because the preliminary heat treatment of the silica together with part or the whole of the diorganopolysiloxane enhances the affinity between the two components and produces effects such as suppressed aggregation of the silica. For example, the heat treatment may be carried out by heating the components at normal or reduced pressure and a temperature of from 100° C. to the decomposition temperature of the components, preferably a temperature of 100 to 300° C., and more preferably 140 to 200° C., usually for about 3 to 30 hours.

(21) The silica is usually added in a proportion of 1 to 100 wt %, preferably 2 to 50 wt %, and more preferably 5 to 30 wt % relative to the diorganopolysiloxane (A). If the amount of the silica added is less than this range, sufficient coating film strength, coating film hardness and thixotropy cannot be obtained and the coating may fail to achieve a desired film thickness in one coating operation, in particular one spray coating operation. Any amount exceeding the above range may result in an excessively high viscosity of the coating.

(22) The above use of silica produces effects such as that the stability during preparation or storage of the obtainable antifouling coating composition is increased, that the coating exhibits good flowability and thixotropy and can form coating films with a sufficient thickness in a small number of coating operations even on vertical surfaces, and further that the obtainable coating films are excellent and well balanced in terms of such properties as hardness, tensile strength and elongation.

(23) (B) Organosilanes and/or Partial Hydrolyzate Condensates thereof

(24) Preferably, the organosilane and/or the partial hydrolyzate condensate thereof (B) is a compound and/or a partial hydrolyzate condensate thereof represented by General Formula [II] below.
R.sup.2.sub.dSiY.sub.4-d  [II]

(25) In General Formula [II], R.sup.2 indicates independently at each occurrence a hydrocarbon group of 1 to 6 carbon atoms, for example, a linear or branched alkyl group such as methyl, ethyl or propyl group, a cycloalkyl group such as cyclohexyl group, an alkenyl group such as vinyl group, or an aryl group such as phenyl group, and is preferably a methyl group or an ethyl group.

(26) In General Formula [II], Y indicates independently at each occurrence a hydrolyzable group. Examples thereof include oxime groups, acetyloxy groups, alkoxy groups, acyloxy groups, alkenyloxy groups, iminoxy groups, amino groups, amide groups and aminoxy groups, with alkoxy groups being preferable.

(27) Preferred oxime groups are those having a total of 1 to 10 carbon atoms. Examples include dimethyl ketoxime, methyl ethyl ketoxime, diethyl ketoxime and methyl isopropyl ketoxime.

(28) Preferred acetyloxy groups are aliphatic such groups having a total of 1 to 10 carbon atoms as well as aromatic such groups having a total of 6 to 12 carbon atoms. Examples include acetoxy group, propyloxy group, butyloxy group and benzoyloxy group.

(29) Preferred alkoxy groups are those having a total of 1 to 10 carbon atoms. An oxygen atom may be present between at least one pair of adjacent carbon atoms. Examples include methoxy group, ethoxy group, propoxy group, butoxy group, methoxyethoxy group and ethoxyethoxy group.

(30) Preferred acyloxy groups are aliphatic or aromatic such groups represented by the formula: RCOO— (wherein R is an alkyl group of 1 to 10 carbon atoms or an aromatic group of 6 to 12 carbon atoms). Examples thereof include acetoxy group, propionoxy group, butyloxy group and benzoyloxy group.

(31) Preferred alkenyloxy groups are those having 3 to 10 carbon atoms. Examples thereof include isopropenyloxy group, isobutenyloxy group and 1-ethyl-2-methylvinyloxy group.

(32) Preferred iminoxy groups (═N—OH, also referred to as oxyimino groups or ketoxime groups) are those having about 3 to 10 carbon atoms. Examples thereof include ketoxime group, dimethyl ketoxime group, methyl ethyl ketoxime group, diethyl ketoxime group, cyclopentanoxime group and cyclohexanoxime group.

(33) Preferred amino groups are those having 1 to 10 carbon atoms. Examples thereof include N-methylamino group, N-ethylamino group, N-propylamino group, N-butylamino group, N,N-dimethylamino group, N,N-diethylamino group and cyclohexylamino group.

(34) Preferred amide groups are those having a total of 2 to 10 carbon atoms. Examples thereof include N-methylacetamide group, N-ethylacetamide group and N-methylbenzamide group.

(35) Preferred aminoxy groups are those having a total of 2 to 10 carbon atoms. Examples thereof include N,N-dimethylaminoxy group and N,N-diethylaminoxy group.

(36) The letter d is an integer of 0 to 2, and is preferably 0.

(37) Commercially available organosilanes may be used. Exemplary tetraethyl orthosilicates include “ETHYL SILICATE 28” (manufactured by COLCOAT CO., LTD.) and “ETHYL ORTHOSILICATE” (manufactured by Tama Chemicals Co., Ltd.). Exemplary partial hydrolyzate condensates of tetraethyl orthosilicates include “SILICATE 40” (manufactured by Tama Chemicals Co., Ltd.) and “TES40 WN” (manufactured by Wacker Asahikasei Silicone Co., Ltd.). Exemplary alkyl trialkoxysilanes include “KBM-13” (manufactured by Shin-Etsu Chemical Co., Ltd.).

(38) In the antifouling coating composition which may include a solvent, the organosilane and/or the partial hydrolyzate condensate thereof (B) having at least two hydrolyzable groups described above in the molecule may be present in 0.1 to 50 wt %, and is usually present in 1 to 30 wt %, and preferably 3 to 15 wt %. This content ensures that the coating composition maintains an appropriate curing rate and is cured to give coating films exhibiting excellent coating film strength and rubber properties.

(39) (C) Pyrithione Metal Salts

(40) Preferably, the pyrithione metal salt (C) is a compound or a mixture of two or more compounds selected from compounds represented by General Formula [III] below.

(41) ##STR00004##

(42) In General Formula [III], R.sup.3 indicates independently at each occurrence a hydrogen atom; an alkyl group of 1 to 6 carbon atoms, for example, a linear or branched alkyl group such as methyl, ethyl or propyl group; a cycloalkyl group such as cyclohexyl group; an alkenyl group such as vinyl group; an aryl group such as phenyl group; an alkoxy group of 1 to 6 carbon atoms, for example, a methoxy, ethoxy or propoxy group; or a halogenated alkyl group of 1 to 6 carbon atoms, for example, a trifluoromethyl group; and preferably indicates a hydrogen atom.

(43) M indicates a metal Zn, Cu, Na, Mg, Ca, Ba, Fe or Sr, and is preferably Zn or Cu. The letter n is the valence of the metal M, and is preferably 2.

(44) In the antifouling coating composition which may include a solvent, the pyrithione metal salt (C) may be present in .1 to 50 wt %, and is usually present in 1 to 30 wt %, preferably 3 to 20 wt %, and more preferably 5 to 15 wt %. Further, the pyrithione metal salt (C) is usually present in a dry coating film at 1 to 40 wt %, and preferably 3 to 25 wt %. The pyrithione metal salt (C) is usually used in 1 to 80 wt %, and preferably 8 to 30 wt % relative to the diorganopolysiloxane (A). Further, the pyrithione metal salt (C) is usually used in 30 to 100,000 wt %, preferably 150 to 10,000 wt %, and more preferably 600 to 5,000 wt % relative to an ether-modified organopolysiloxane which is a typical anti-sagging and anti-settling agent.

(45) In the antifouling coating composition of the invention, the pyrithione metal salt (C) functions as an effective ingredient for achieving excellent antifouling properties, in particular, anti-sliming properties, and also as an effective ingredient for improving storage stability.

(46) The reason why the addition of the pyrithione metal salt (C) provides the above characteristics is probably because the terminal hydroxyl groups of the diorganopolysiloxane (A) interact with the metal center of the pyrithione metal salt (C) which easily gives vacant coordination sites. This interaction allows the pyrithione metal salt to be eluted from the inside of the antifouling coating film at a suitable rate, thus markedly reducing the attachment of slime over a long period. Further, the interaction suppresses the occurrence of chemical reactions that may change properties of the coating during storage, with the result that an appropriate coating film-forming capability is maintained until the preparation of the antifouling coating composition or the coating film-forming capability is ameliorated during the storage. In detail, the phrase that an appropriate coating film-forming capability is maintained indicates that the coating remains at substantially the same level before and after storage in terms of the capability in which the coating shows low viscosity and good sprayability as well as can be applied in a large thickness by exhibiting good sagging resistance. The phrase that the coating film-forming capability is ameliorated means that the viscosity is reduced to allow for improved sprayability and/or the sagging resistance is improved to allow for thicker application. An increase in viscosity does not cause problems in the application as long as the increase does not adversely affect sprayability and sagging resistance (thick applicability).

(47) (Optional Ingredients)

(48) In addition to the diorganopolysiloxane (A), the organosilane and/or the partial hydrolyzate condensate thereof (B) having at least two hydrolyzable groups in the molecule, and the pyrithione metal salt (C), the antifouling coating composition according to the present invention may contain other ingredients such as silicone oils (D), fillers (E), anti-sagging and anti-settling agents (F), curing catalysts (G), silane coupling agents (H), antifouling agents (I) other than the components (C), additional coating film-forming components (J), inorganic dehydrating agents (K), flame retardants (L), thixotropic agents (M) and thermal conductivity improvers (N).

(49) (D) Silicone Oils

(50) Preferred silicone oils (D) are those which can bleed out from cured products of the antifouling coating. Examples of such silicone oils (D) include phenyl-modified organopolysiloxanes represented by Formula [IV] below.
(R.sup.4).sub.3SiO(SiR.sup.4.sub.2O).sub.nSi(R.sup.4).sub.3  [IV]

(51) In Formula [IV], R.sup.4 indicates independently at each occurrence an alkyl, aryl, aralkyl or fluoroalkyl group of 1 to 10 carbon atoms, at least one of R.sup.4s is a phenyl group, and the letter n indicates an integer of 0 to 150.

(52) Of the silicone oils (D), those silicone oils represented by Formula [IV] usually have a weight average molecular weight of 180 to 20,000, preferably 1,000 to 10,000, and usually have a viscosity at 23° C. of 20 to 30,000 mPa.Math.s, preferably 50 to 3,000 mPa.Math.s.

(53) Of the silicone oils represented by Formula [IV], for example, methyl phenyl silicone oils are preferable that are derived from dimethyl silicone oils in which R.sup.4s are all methyl groups by the substitution (modification) of part of the methyl groups with phenyl groups.

(54) Examples of the methyl phenyl silicone oils include products sold under the trade names of “KF-54”, “KF-56” and “KF-50” (manufactured by Shin-Etsu Chemical Co., Ltd.), “SH510” and “SH550” (manufactured by Dow Corning Toray Co., Ltd.) and “TSF431” (manufactured by Toshiba Silicone).

(55) In the antifouling coating composition which may include a solvent, the silicone oils (D) are preferably present in a total content of 0.1 to 50 wt %, and more preferably 3 to 20 wt %. This content of the silicone oils (D) ensures that the obtainable antifouling coating can form antifouling coating films with excellent antifouling properties and coating film strength which tend to function as satisfactory antifouling layers. If the content is below the above range, antifouling properties may be deteriorated. Any content exceeding the above range may result in a decrease in coating film strength.

(56) (E) Fillers

(57) The fillers (E) may be known organic and inorganic pigments and other types of fillers. Examples of the organic pigments include carbon black, phthalocyanine blue and iron blue. Examples of the inorganic pigments include neutral and nonreactive pigments such as titanium white (titanium oxide), red oxide, barite powder, silica, talc, white chalk and iron oxide powder; and basic pigments reactive with acidic substances in the coating (active pigments) such as Chinese white (ZnO, zinc oxide), lead white, red lead, zinc powder and lead suboxide powder. Examples of other types of fillers include metal oxides such as diatomaceous earth and alumina; metal carbonate salts such as calcium carbonate, magnesium carbonate and zinc carbonate; and others such as asbestos, glass fibers, quartz powder, aluminum hydroxide, gold powder, silver powder, surface-treated calcium carbonate and glass balloon. These fillers may be surface treated with silane compounds. The fillers may be used singly, or two or more may be used in combination. Further, the fillers may include colorants such as dyes.

(58) The addition of the fillers (E) can improve the strength of the coating films. Further, the coating which contains the fillers can conceal a primer coating film to prevent UV degradation of the primer coating film. In the antifouling coating composition which may include a solvent, the fillers (E) may be preferably present in 0.1 to 30 wt %.

(59) (F) Anti-sagging and Anti-settling Agents (Thickening Agents)

(60) Examples of the anti-sagging and anti-settling agents (thickening agents) (F) include ether-modified organopolysiloxanes, organic clay waxes (such as stearate salts, lecithin salts and alkylsulfonate salts of Al, Ca and Zn), organic waxes (such as polyethylene waxes, polyethylene oxide waxes, amide waxes, polyamide waxes and hydrogenated castor oil waxes), mixtures of organic clay waxes and organic waxes, and synthetic fine powdery silica. Of these, ether-modified organopolysiloxanes and synthetic fine powdery silica are preferable.

(61) Of the components (F), compounds represented by Formula [V] below may be used as the ether-modified organopolysiloxanes.
(R.sup.5).sub.3SiO(SiR.sup.5.sub.2O).sub.nSi(R.sup.5).sub.3  [V]

(62) In Formula [V], R.sup.5 indicates independently at each occurrence a hydrogen atom; an alkyl, aryl or aralkyl group of 1 to 10 carbon atoms; a hydroxyl group; a hydrolyzable group Y; or a linear, branched or alicyclic hydrocarbon chain with an ether group optionally terminated with a hydroxyl group, a —SiR.sub.xY.sub.(3-x) group (x is 0 to 2) or an alkyl or acyl group of 1 to 6 carbon atoms. At least one of R.sup.5s is a linear, branched or alicyclic hydrocarbon chain with an ether group optionally terminated with a hydroxyl group, a —SiR.sub.xY.sub.(3-x) group (x is 0 to 2) or an alkyl or acyl group of 1 to 6 carbon atoms. The hydrolyzable group Y is the same as defined in Formula [II]. The letter n indicates an integer of 1 or greater.

(63) Examples of the ether-modified organopolysiloxanes include products such as “FZ-2191” (alkylene glycol-modified silicone oil, Dow Corning Toray Co., Ltd.), “FZ-2101” (alkylene glycol-modified silicone oil, Dow Corning Toray Co., Ltd.), “X-22-4272” (hydroxyl-terminated/alkylene glycol-modified silicone oil, Shin-Etsu Chemical Co., Ltd.), and “BY16-839” (alicyclic epoxy-modified silicone oil, Dow Corning Toray Co., Ltd.).

(64) Of the ether-modified organopolysiloxanes, those having a viscosity at 23° C. of 100 to 10,000 mPa.Math.s are usually used.

(65) Of the components (F), the polyamide waxes maybe products sold by Kusumoto Chemicals, Ltd. under the trade names of “DISPARLON 305”, “DISPARLON 4200-20” and “DISPARLON A630-20X”.

(66) The addition of the anti-sagging and anti-settling agents (F) can improve the sagging resistance of the coating films. However, adding these components in an excessively large amount can result in decreases in terms of adhesion, sprayability of the coating and leveling properties of the coating films. Thus, the amount of the anti-sagging and anti-settling agents (F), in particular, the representative ether-modified organopolysiloxanes of Formula [V], is usually 0.01 to 10 wt %, and preferably 0.1 to 3 wt % in the antifouling coating composition which may include a solvent. Further, the content of such components in a dry coating film is usually 0.01 to 10 wt %, and preferably 0.1 to 3 wt %.

(67) (G) Curing Catalysts

(68) The curing catalysts (G) may be used to accelerate the curing reaction between the diorganopolysiloxane (A) and the organosilane and/or the partial hydrolyzate condensate thereof (B). Suitable examples of such curing catalysts (G) include those described in JP-A-H04-106156 (Japanese Patent No. 2522854). Specific examples include tin carboxylates such as tin naphthenate and tin oleate; tin compounds such as dibutyltin diacetate, dibutyltin acetoacetonate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dioleate, dibutyltin oxide, dibutyltin dimethoxide, dibutyltin dipentoate, dibutyltin dineodecanoate, dioctyltin dineodecanoate, bis(dibutyltin laurate)oxide, dibutyl bis(triethoxysiloxy)tin, bis(dibutyltin acetate)oxide, dibutyltin bis(ethyl maleate) and dioctyltin bis(ethyl maleate); titanate esters or titanium chelate compounds such as tetraisopropoxytitanium, tetra-n-butoxytitanium, tetrakis(2-ethylhexoxy)titanium, dipropoxybis(acetylacetonato)titanium and titanium isopropoxyoctyl glycol; organometallic compounds such as zinc naphthenate, zinc stearate, zinc 2-ethyloctoate, iron 2-ethylhexoate, cobalt 2-ethylhexoate, manganese 2-ethylhexoate, cobalt naphthenate and alkoxyaluminum compounds; aminoalkyl-substituted alkoxysilanes such as 3-aminopropyltrimethoxysilane and N-β-(aminoethyl) γ-aminopropyl trimethoxysilane; amine compounds and salts thereof such as hexylamine, dodecyldodecylamine phosphate, dimethylhydroxylamine and diethylhydroxylamine; quaternary ammonium salts such as benzyltriethyl ammonium acetate; lower fatty acid salts of alkali metals such as potassium acetate, sodium acetate and lithium oxalate; and guanidyl group-containing silanes or siloxanes such as tetramethylguanidylpropyltrimethoxysilane, tetramethylguanidylpropylmethyldimethoxysilane and tetramethylguanidylpropyltris(trimethylsiloxy)silane.

(69) By the addition of the curing catalysts (G), the formation of coating films is accelerated and dry coating films can be obtained in a shorter time. The curing catalysts (G) may be used in an amount of not more than 10 wt %, and preferably not more than 1 wt % in the antifouling coating composition which may include a solvent. In the case where the catalysts are used, the lower limit of the amount thereof is preferably .1 wt %, and more preferably 0.01 wt %.

(70) (H) Silane Coupling Agents

(71) Preferred silane coupling agents (H) are those silane coupling agents having one, or two or more groups such as alkoxysilyl group, amino group, imino group, epoxy group, hydrosilyl group, mercapto group, isocyanate group and (meth)acryl group. In particular, those having an amino group are preferable. Examples of the silane coupling agents having an amino group include 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and 3-(2-(2-aminoethyl)aminoethyl)aminopropyltrimethoxysilane. Examples of other silane coupling agents include 3-glycidoxypropylmethyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, N-phenylpropyltrimethoxysilane and N-phenylpropyltriethoxysilane. Mixtures of the above silane coupling agents may also be used.

(72) The addition of the silane coupling agents (H) can further increase the adhesion of the coating films with respect to primer coating films or substrates, or can increase the strength of the antifouling coating films. The amount of the silane coupling agents (H) added is preferably 0.01 to 1 wt % in the antifouling coating composition which may include a solvent.

(73) (I) Antifouling Agents other than Pyrithione Metal Salts (C)

(74) The antifouling agents (I) may be any of inorganic and organic antifouling agents other than the pyrithione metal salts (C). Known inorganic antifouling agents may be used, with copper, cuprous oxide, copper thiocyanate and inorganic copper compounds being preferable. Examples of the organic antifouling agents include tetramethylthiuram disulfide, carbamate compounds (e.g., zinc dimethyldithiocarbamate and manganese 2-ethylenebisdithiocarbamate) and 2,4,5,6-tetrachloroisophthalonitrile. The antifouling agents (I) may be used singly, or a plurality of antifouling agents may be used as a mixture.

(75) The addition of the antifouling agents (I) can further enhance the antifouling properties of the coating films in seawater. The amount of the antifouling agents (I) added is preferably 0.1 to 30 wt % in the antifouling coating composition which may include a solvent.

(76) (J) Additional Coating Film-forming Components

(77) Additional coating film-forming components (J) other than the components such as the diorganopolysiloxanes (A) may be used while still achieving the objects of the invention. Examples of such “additional coating film-forming components” include resins which are hardly soluble or are insoluble in water such as acrylic resins, acryl silicone resins, unsaturated polyester resins, fluororesins, polybutene resins, silicone rubbers, urethane resins (rubbers), polyamide resins, vinyl chloride copolymer resins, chlorinated rubbers (resins), chlorinated olefin resins, styrene-butadiene copolymer resins, ethylene-vinyl acetate copolymer resins, vinyl chloride resins, alkyd resins, coumarone resins, trialkylsilyl acrylate (co)polymers (silyl resins) and petroleum resins.

(78) The addition of the additional coating film-forming components (J) can increase the strength of the coating films. The amount of the additional coating film-forming components (J) added is preferably 0.1 to 30 wt % in the antifouling coating composition which may include a solvent.

(79) (K) Inorganic Dehydrating Agents

(80) Examples of the inorganic dehydrating agents (K) include anhydrous calcium sulfate (CaSO.sub.4), synthetic zeolite adsorbents (available under trade names such as Molecular Sieves) and silicates, with anhydrous calcium sulfate and Molecular Sieves being preferable. One, or two or more inorganic dehydrating agents may be used.

(81) The inorganic dehydrating agents (K) also function as stabilizers. Thus, the addition of these components prevents the occurrence of degradation by water in the antifouling coating composition and can further improve the storage stability. The amount of the inorganic dehydrating agents (K) added is preferably 0.1 to 10 wt % in the antifouling coating composition which may include a solvent.

(82) (L) Flame Retardants

(83) Exemplary flame retardants include antimony oxide and paraffin oxide.

(84) (M) Thixotropic Agents

(85) Exemplary thixotropic agents include polyethylene glycol, polypropylene glycol and derivatives thereof.

(86) (N) Thermal Conductivity Improvers

(87) Exemplary thermal conductivity improvers include boron nitride and aluminum oxide.

(88) (Multiple-component Antifouling Coating Compositions/Kits for Preparation of Antifouling Coating Compositions)

(89) The antifouling coating composition according to the invention is usually provided as a multiple-component coating including two or more components. Each of these components (liquids) comprises one or more ingredients, and is placed in respective packages and thereafter stored in a container such as a can. At the time of application, the contents of those components are mixed and stirred together to give an antifouling coating composition. That is, one aspect of the invention provides a kit for the preparation of the inventive antifouling coating composition that includes the aforementioned components.

(90) In organopolysiloxane antifouling coating compositions, it is generally accepted that the “main agent” is a component which includes an organopolysiloxane as a base of binder resin for the antifouling coating composition, and the “curing agent” is a component which includes a compound capable of reacting with the organopolysiloxane to form crosslinks, and further that the “additive” is a component which includes compounds capable of reacting with the compounds present in both the main agent component and the curing agent component, such as silane coupling agents. The antifouling coating composition of the invention (the kit for the preparation of the composition) may be produced in the form of a two-component system consisting of a main agent component (X) and a curing agent component (Y).

(91) In the case where, for example, the silane coupling agent (H) is used as an optional component, the inventive antifouling coating composition (the kit for the preparation of the composition) may be produced in the form of a three-component system consisting of a main agent component (X), a curing agent component (Y) and an additive component (Z).

(92) The main agent component (X) in the invention includes the diorganopolysiloxane (A) having at least two Si—OH (silanol) groups in the molecule, the pyrithione metal salt (C) and optionally other ingredients. As mentioned hereinabove, part or the whole of the diorganopolysiloxane (A) used in the main agent component (X) may be a heat treated product of the compound with silica. Examples of the optional ingredients which may be present in the main agent component (X) include the silicone oils (D) represented by phenyl-modified organopolysiloxanes, the anti-sagging and anti-settling agents (F) represented by ether-modified organopolysiloxanes, the fillers (E) represented by pigments, the antifouling agents (I) other than the pyrithione metal salts (C), the additional coating film-forming components (J), the inorganic dehydrating agents (K), the flame retardants (L), the thixotropic agents (M) and the thermal conductivity improvers (N).

(93) The main agent component (X) may contain a solvent as required. Known solvents may be used, with examples including aliphatic solvents, aromatic solvents, ketone solvents, ester solvents, ether solvents and alcohol solvents. Examples of the aromatic solvents include xylene and toluene. Examples of the ketone solvents include methyl isobutyl ketone (MIBK) and cyclohexanone. Examples of the ether solvents include propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate (PGMAC). Examples of the alcohol solvents include isopropyl alcohol.

(94) In order for the obtainable antifouling coating composition to exhibit a viscosity suited for application or other operations, the solvents are preferably used in, for example, 0 to 50 wt % relative to the antifouling coating composition. The solvents maybe added in appropriate amounts also to the curing agent component (Y) and the additive component (Z).

(95) The curing agent component (Y) in the invention includes the organosilane and/or the partial hydrolyzate condensate thereof (B) having at least two hydrolyzable groups in the molecule and optional ingredients having high reactivity with the components in the main agent. Examples of the optional ingredients which may be present in the curing agent component (Y) include the curing catalyst (G), the silicone oils (D) represented by phenyl-modified organopolysiloxanes, and the anti-sagging and anti-settling agents (F) represented by ether-modified organopolysiloxanes. The silicone oils (D) represented by phenyl-modified organopolysiloxanes, and the anti-sagging and anti-settling agents (F) represented by ether-modified organopolysiloxanes may be added to any of the main agent component (X) and the curing agent component (Y) as long as the addition of such ingredients does not induce undesired reactions with other ingredients present in the components (X) and (Y).

(96) The additive component (Z) in the invention includes optional ingredients having high reactivity with the ingredients in the main agent component (X) and the curing agent component (Y). Examples of the optional ingredients include the silane coupling agents (H).

(97) For example, the antifouling coating composition of the invention may be obtained by adding the ingredients for constituting the multiple-component antifouling coating, namely, the contents of the components (packages) of the aforementioned kit and further optional ingredients as required sequentially or simultaneously and mixing these ingredients together in accordance with common procedures.

(98) —Antifouling Substrates—

(99) A method for manufacturing antifouling substrates according to the present invention includes a step of coating or impregnating a substrate with the aforementioned inventive antifouling coating composition, and a step of curing the composition that has been applied to coat or impregnate the substrate.

(100) In detail, after sufficient stirring, the resultant antifouling coating composition is applied to a substrate by spraying or another method to coat or impregnate the substrate and is cured by being allowed to stand in air at room temperature for about 0.5 to 3 days or by being subjected to air blowing at an elevated temperature, thereby producing an antifouling substrate having an antifouling coating film on the surface. The film thickness of the cured antifouling coating film may be controlled to a desired thickness in accordance with factors such as purposes of use. Antifouling coating films having excellent antifouling performance may be obtained by applying the antifouling coating composition one to several times usually in a thickness of 30 to 400 μm, and preferably 30 to 200 μm per application, for example, 30 to 150 μm per application, and thereafter curing the composition so as to achieve a cured film thickness of, for example, 150 to 1000 μm.

(101) In a wide range of industrial fields such as power generation, port and civil engineering construction and marine vessels (building and repairing), the antifouling coating compositions of the invention may be used to protect the surface of substrates to be placed in contact with seawater or fresh water from the attachment of marine organisms and thereby to allow the substrates to maintain their normal functions for long periods. Examples of such substrates include marine vessels (such as marine vessel shells), fishery materials (such as ropes, fishing nets, fishing gears, floats and buoys), underwater structures such as water supply inlets and drains in thermal power plants and nuclear power plants, seawater equipment (such as seawater pumps), mega-floats, coast roads, submarine tunnels, port facilities, and sludge diffusion prevention films in various offshore construction works for building structures such as canals and waterways.

(102) The inventive antifouling coating compositions have an excellent balance between low viscosity and high thixotropy, and thus exhibit good application workability and can at the same time form relatively thick coating films even in one coating operation. Because of these characteristics, the inventive antifouling coating compositions can form coating films having excellent properties such as coating film strength and surface smoothness.

(103) Applying the antifouling coating composition one time or several times as required and curing the composition according to common procedures result in antifouling substrates such as marine vessels and underwater structures coated with the antifouling coating films which exhibit excellent antifouling properties and have appropriate plasticity even when formed in a large thickness so as to display excellent crack resistance. A wide range of known application means may be used for the application of the antifouling coating composition, with examples including brushes, rolls, sprays and dip coaters. The organopolysiloxane antifouling coating compositions of the invention have characteristics suited for spray coating.

(104) In common with antifouling coating films from usual organopolysiloxanes, the antifouling coating films formed from the inventive antifouling coating compositions have low surface free energy and can therefore suppress the attachment of various aquatic organisms. Even if such organisms have become attached, they are easily detached by the resistance of the flow of seawater or fresh water. In addition, the antifouling coating films formed from the inventive antifouling coating compositions can release the antifouling agents such as the pyrithione metal salts (C) persistently over long periods. Because the surface of the inventive antifouling substrates is coated with such antifouling coating films, excellent antifouling effects can be achieved continuously for long terms not only against the attachment of aquatic organisms such as sea lettuce, barnacles, green algae, serpula, oysters and Bugula neritina (for example, Schizoporellidae) but also against the fouling by slime. Further, these antifouling substrates have little impacts on the environment.

(105) The antifouling coating compositions of the invention may be applied directly to substrates to coat or impregnate the substrates. Even in the case where the antifouling coating compositions prepared according to the invention are applied directly to substrates such as water supply inlets and drains in nuclear power plants, mega-floats and marine vessels made of such materials as fiber-reinforced plastics (FRP), steel, iron, wood and aluminum alloys, the compositions can exhibit good adhesion with respect to the surface of these substrates (bases).

(106) Further, the antifouling coating compositions of the invention may be applied to already coated substrates. That is, the inventive antifouling coating compositions may be applied to the surface of substrates such as marine vessels and underwater structures preliminarily coated with base films (primer films) of coatings such as antirust agents and primers. Furthermore, the antifouling coating compositions of the invention may be applied as overcoatings to repair the surface of substrates such as marine vessels, in particular FRP boats, and underwater structures which have been already coated with conventional antifouling coatings or with the inventive antifouling coating compositions. The antifouling coating compositions of the invention may be placed in direct contact with any types of underlying coating films without limitation. Similarly to general organopolysiloxane antifouling coatings, for example, the inventive antifouling coating compositions may be applied to coating films formed from coatings based on resins such as epoxy resins, urethane resins and silicone resins. The antifouling coating compositions according to the present invention can be prepared to exhibit good adhesion with respect to the surface of these coating films.

(107) —Methods for Improving Storage Stability of Antifouling Coating Compositions—

(108) A method for improving the storage stability of an antifouling coating composition according to the present invention will be discussed. Here, the antifouling coating composition is in the form of a kit for the preparation of the antifouling coating composition, the set being a multiple-component system including respective packages of a component including a diorganopolysiloxane (A) having at least two silanol groups in the molecule, and a component including an organosilane and/or a partial hydrolyzate condensate thereof (B) having at least two hydrolyzable groups in the molecule. The method is characterized in that a pyrithione metal salt (C) is added to the component including the diorganopolysiloxane (A).

(109) In this method, the pyrithione metal salt (C) functions as an effective ingredient for improving the storage stability of the antifouling coating composition. It is needless to mention that, in this case too, the pyrithione metal salt (C) naturally functions as an effective ingredient for preventing the attachment of organisms such as slime, namely, as an inherent antifouling agent.

(110) The phrase that the storage stability is improved indicates that changes are suppressed from occurring during storage in terms of the properties of the antifouling coating composition, in particular, the diorganopolysiloxane (A) present in the main agent component (X) in the multiple-component kit for the preparation of the antifouling coating composition. For example, specific effects are obtained such as that the antifouling coating composition is prepared by mixing the contents of the multiple-component kit without an increase in viscosity and the obtained composition maintains appropriate viscosity and good workability such as sprayability, as well as that a decrease in sagging resistance is suppressed and the composition maintains thick applicability by exhibiting good sagging resistance. As mentioned hereinabove, these effects are probably associated with the interaction between the pyrithione metal salt (C) with the terminal hydroxyl groups of the diorganopolysiloxane (A).

(111) Details regarding the ingredients present in the antifouling coating composition to be improved in terms of storage stability by the inventive method are similar to those described hereinabove. The same applies to the components constituting the kit for the preparation of the antifouling coating composition.

EXAMPLES

(112) The present invention will be described in greater detail by presenting examples hereinbelow. The invention is not limited to the examples described below and may be modified without departing from the scope and spirit of the invention.

(113) (Preparation of Antifouling Coating Compositions)

(114) Table 1 describes information such as generic names, manufacturers and trade names of ingredients for antifouling coating compositions used in examples. In Table 1, the weight average molecular weight Mw was measured by gel permeation chromatography (GPC) using a calibration curve prepared with respect to standard polystyrenes.

(115) TABLE-US-00001 TABLE 1 Packs Components Generic names, chemical formulae, etc. Main agent Organopolysiloxane 1 HO—[Si(CH.sub.3).sub.2—O—].sub.n—H Mw 28,500 component Organopolysiloxane 2 HO—[Si(CH.sub.3).sub.2—O—].sub.n—H Mw 31,000 (X) Silica Silica surface-treated with hexamethyldisilazane Red pigment Red iron oxide White pigment Titanium oxide Zinc pyrithione Zn(—S—C.sub.5H.sub.4N—O—).sub.2 Copper pyrithione Cu(—S—C.sub.5H.sub.4N—O—).sub.2 Irgarol 2-methylthio-4-t-butylamino-6-cyclopropylamino-triazine Xylene Xylene Curing Partially hydrolyzed H.sub.5C.sub.2O—[Si(OC.sub.2H.sub.5).sub.2—O—].sub.n—C.sub.2H.sub.5 agent and condensed component organosilane (Y) Phenyl-modified H.sub.3C—[Si(CH.sub.3).sub.2—O—].sub.n—[Si(C.sub.6H.sub.5).sub.2—O—].sub.m—CH.sub.3 Phenyl modification rate 5%, organopolysiloxane 1,000 mPa .Math. s Ether-modified H.sub.3C—[Si(CH.sub.3).sub.2—O—].sub.n—[Si(CH.sub.3)(—R—(—C.sub.2H.sub.4—O—).sub.1—H)—].sub.m—CH organopolysiloxane 1 900 mPa .Math. s Ether-modified H.sub.3C—[Si(CH.sub.3).sub.2—O—].sub.n—[Si(CH.sub.3)((—C.sub.2H.sub.4—O—).sub.1—(—C.sub.3H.sub.6—O—).sub.o—R)—].sub.m—CH.sub.3 organopolysiloxane 2 1700 mPa .Math. s Ether-modified HO—(—C.sub.2H.sub.4—O—).sub.1—C.sub.3H.sub.6—[Si(CH.sub.3).sub.2—O—].sub.m—Si(CH.sub.3).sub.2—C.sub.3H.sub.6—(—O—C.sub.2H.sub.4—).sub.n—OH organopolysiloxane 3 270 mPa .Math. s Tin catalyst Dibutyltin dilaurate Acetylacetone Acetylacetone Xylene Xylene Additive Aminosilane compound (CH.sub.3O).sub.3—Si—C.sub.3H.sub.6—NH—C.sub.2H.sub.4—NH.sub.2 component (Z) Xylene Xylene Packs Components Manufacturers Trade names Main agent Organopolysiloxane 1 component (X) Organopolysiloxane 2 Silica Red pigment TODA KOGYO CORP. KN-V White pigment SAKAI CHEMICAL INDUSTRY CO., LTD. TITONE R-5N Zinc pyrithione Arch Chemicals Japan, Inc. Zinc Omadine Powder Copper pyrithione Arch Chemicals Japan, Inc. Copper Omadine Powder Irgarol BASF Japan Irgarol 1051 Xylene Curing agent Partially hydrolyzed and Wacker Asahikasei Silicone Co., Ltd. TES40 WN component (Y) condensed organosilane Phenyl-modified organopolysiloxane Ether-modified organopolysiloxane 1 Ether-modified organopolysiloxane 2 Ether-modified organopolysiloxane 3 Tin catalyst DIC Corporation Gleck TL Acetylacetone Xylene Additive Aminosilane compound Shin-Etsu Chemical Co., Ltd. KBM-603 component (Z) Xylene

(116) Main agent components (X), curing agent components (Y) and additive components (Z) in amounts described in Table 2 were thoroughly mixed together homogeneously with a disperser. Thus, antifouling coating compositions of Examples 1 to 11 and Comparative Examples 1 to 4 were prepared.

(117) [Evaluation Methods]

(118) With regard to each of the antifouling coating compositions of Examples 1 to 11 and Comparative Examples 1 to 4 as prepared above and the antifouling coating films formed therefrom, property tests and antifouling tests described below were carried out. The results are described in Table 2.

(119) <Coating/Coating Film Property Tests>

(120) (Viscosity)

(121) To determine the viscosity, each of the compositions was analyzed at 23° C. with a Stormer viscometer (manufacturer: TAIYU KIZAI CO., LTD., product name: Stormer Viscometer, model: 691).

(122) (Sagging Resistance)

(123) To evaluate sagging resistance, each of the compositions was applied to a tin plate on a flat table using a box-type sag tester illustrated in JIS K 5400 (1990) 6.4. Immediately after the film thickness was measured with a wet film gauge, the test plate (the tin plate) was held vertical so that the track of the sag tester became horizontal. The sagging resistance of the film was thus examined. The critical film thickness prior to the occurrence of sagging was determined with respect to each composition based on the criteria in which the sagging resistance was evaluated to be acceptable when the length of the sample which had sagged from a coating layer toward a downward adjacent coating layer was less than half the space between the coating layers.

(124) (Adhesion)

(125) Sandblasted plates were provided which had been coated with an epoxy-based anticorrosive coating (trade name: BANNOH 500, manufactured by CHUGOKU MARINE PAINTS, LTD.) in a thickness of 100 μm and further with a polyurethane binder coating (trade name: CMP BIOCLEAN SG, manufactured by CHUGOKU MARINE PAINTS, LTD.) in a thickness of 100 μm. To the coated plates, each of the compositions was applied such that the dry film thickness would be 200 μm. The compositions were dried at room temperature for one day. Thereafter, a straight incision was cut with a knife to a depth reaching the CMP BIOCLEAN SG coating film layer and the top surface was strongly rubbed in the direction perpendicular to the incision, thereby evaluating the adhesion. If the adhesion is low, rubbing causes a separation between the composition layer and the CMP BIOCLEAN SG coating film layer.

(126) (Storage Stability)

(127) After the main agent components (X) were prepared, they were subjected to an accelerated test in which the components were stored at 40° C. for 50 days and were thereafter tested to determine the above properties, thereby evaluating the storage stability of the coatings.

(128) <Antifouling Tests>

(129) (Preparation of Test Plates)

(130) Sandblasted plates were provided which had been coated with an epoxy-based anticorrosive coating (trade name: BANNOH 500, manufactured by CHUGOKU MARINE PAINTS, LTD.) in a thickness of 100 μm and further with a polyurethane binder coating (trade name: CMP BIOCLEAN SG, manufactured by CHUGOKU MARINE PAINTS, LTD.) in a thickness of 100 μm. To the coated plates, each of the compositions of Examples 1 to 11 and Comparative Examples 1 to 4 was applied such that the dry film thickness would be 200 μm.

(131) (Method of Testing Static Antifouling Properties)

(132) After the test plates were dried at room temperature for 7 days, they were immersed in seawater in Miyajima Bay, Hiroshima, Japan, under static conditions. The proportions of the areas fouled by organisms on the surface of the test plates were evaluated by visual observation every three months.

(133) (Method of Testing Dynamic Antifouling Properties)

(134) After the test plates were dried at room temperature for 7 days, they were immersed off the coast in Kure, Hiroshima, Japan, while generating a stream of water with rotors such that the speed was approximately 15 knots. The proportions of the areas fouled by organisms on the surface of the test plates were evaluated by visual observation every three months.

(135) (Evaluation Points)

(136) 0: No aquatic organisms had become attached.

(137) 0.5: Aquatic organisms had become attached to more than 0% and not more than 10% of the surface.

(138) 1: Aquatic organisms had become attached to more than 10% and not more than 20% of the surface.

(139) 2: Aquatic organisms had become attached to more than 20% and not more than 30% of the surface.

(140) 3: Aquatic organisms had become attached to more than 30% and not more than 40% of the surface.

(141) 4: Aquatic organisms had become attached to more than 40% and not more than 50% of the surface.

(142) 5: Aquatic organisms had become attached to from more than 50% to about 100% of the surface.

(143) TABLE-US-00002 TABLE 2 Generic names, chemical Packs formulae, etc. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Compositions Main agent Organopolysiloxane 1 and 59.8 59.8 56.8 56.1 50.6 component silica (X) Organopolysiloxane 2 and silica Red pigment 5.5 5.4 5.1 White pigment 4.0 4.0 Zinc pyrithione 5.0 5.5 7.2 10.1 Copper pyrithione 5.0 Irgarol Xylene 9.2 12.2 15.8 13.4 20.7 Subtotal 77.9 80.9 83.6 82.2 86.5 Curing agent Partially hydrolyzed and 3.0 3.0 2.9 2.8 2.5 component condensed organosilane (Y) Phenyl-modified 5.0 5.0 4.8 4.7 4.2 organopolysiloxane Ether-modified 0.1 0.1 0.1 0.1 0.1 organopolysiloxane 1 Ether-modified organopolysiloxane 2 Ether-modified organopolysiloxane 3 Tin catalyst 0.6 0.6 0.6 0.6 0.4 Acetylacetone 5.0 5.0 4.8 4.7 4.2 Xylene 2.3 2.3 2.3 2.2 1.2 Subtotal 16.0 16.0 15.5 15.1 12.6 Additive Aminosilane compound 0.1 0.1 0.1 0.1 0.1 component Xylene 2.9 2.9 0.8 2.7 0.8 (Z) Subtotal 3.0 3.0 0.9 2.8 0.9 Total 96.9 99.9 100.0 100.0 100.0 Properties of Immediately Sagging resistance 300 350 200 200 350 coatings after Critical wet film thickness fabrication prior to occurrence of sagging [μm] Stormer viscosity [KU] 82 82 75 75 70 After Sagging resistance 300 350 200 250 350 accelerated Critical wet film thickness stability prior to occurrence of sagging test at 40° C. [μm] for 50 days Stormer viscosity [KU] 82 82 72 73 72 Adhesion Good Good Good Good Good Antifouling Static 3 months 0 0.5 0 0 0 properties immersion 6 months 2 2 2 2 2 9 months 0.5 1 0.5 0.5 0.5 12 months 0.5 0 0.5 0.5 0.5 Dynamic 3 months 0 0 0 0 0 immersion 6 months 0 0.5 0 0 0 9 months 0 0.5 0 0 0 12 months 0 0.5 1 1 1 Generic names, chemical Packs formulae, etc. Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10 Compositions Main agent Organopolysiloxane 1 and 32.8 58.2 43.1 54.2 component silica (X) Organopolysiloxane 2 and 51.8 silica Red pigment 5.5 5.2 5.6 7.2 5.4 White pigment Zinc pyrithione 18.2 4.3 4.5 Copper pyrithione 3.7 6.0 Irgarol Xylene 28.7 25.4 13.9 24.5 19.8 Subtotal 85.2 86.7 81.5 80.8 83.9 Curing agent Partially hydrolyzed and 2.7 2.6 2.9 3.6 2.7 component condensed organosilane (Y) Phenyl-modified 4.6 4.3 4.9 6.0 4.5 organopolysiloxane Ether-modified 0.1 0.1 0.1 0.1 organopolysiloxane 1 Ether-modified 2.1 organopolysiloxane 2 Ether-modified organopolysiloxane 3 Tin catalyst 0.5 0.4 0.6 0.6 0.5 Acetylacetone 4.6 4.3 4.9 6.0 4.5 Xylene 1.3 0.7 2.2 1.7 0.9 Subtotal 13.8 12.4 15.5 18.0 15.2 Additive Aminosilane compound 0.1 0.1 0.1 0.1 0.1 component Xylene 0.8 0.8 2.8 1.1 0.8 (Z) Subtotal 0.9 0.9 2.9 1.2 0.9 Total 99.9 100.0 99.9 100.0 100.0 Properties of Immediately Sagging resistance 250 250 200 300 250 coatings after Critical wet film thickness fabrication prior to occurrence of sagging [μm] Stormer viscosity [KU] 69 72 75 72 75 After Sagging resistance 300 350 200 350 250 accelerated Critical wet film thickness stability prior to occurrence of sagging test at 40° C. [μm] for 50 days Stormer viscosity [KU] 72 76 73 70 73 Adhesion Good Good Good Good Good Antifouling Static 3 months 0 0 0 0 0 properties immersion 6 months 3 2 3 2 2 9 months 1 0.5 1 0.5 0.5 12 months 0 0.5 0.5 0.5 0.5 Dynamic 3 months 0 0 0 0 0 immersion 6 months 1 0 0 0 0 9 months 1 0 0 0 0 12 months 0.5 1 1 1 1 Generic names, chemical Comp. Comp. Comp. Comp. Packs formulae, etc. Ex. 11 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Compositions Main agent Organopolysiloxane 1 and 52.3 59.8 59.8 60.5 component silica (X) Organopolysiloxane 2 and 55.8 silica Red pigment 5.2 7.8 5.6 White pigment 7.7 4.0 Zinc pyrithione 4.4 Copper pyrithione Irgarol 5.0 Xylene 23.6 6.4 9.2 12.5 23.7 Subtotal 85.5 73.9 77.9 80.8 85.1 Curing agent Partially hydrolyzed and 2.6 3.0 3.0 3.0 2.8 component condensed organosilane (Y) Phenyl-modified 4.4 5.0 5.0 5.1 4.6 organopolysiloxane Ether-modified 0.1 0.1 0.1 0.1 organopolysiloxane 1 Ether-modified rganopolysiloxane 2 Ether-modified 0.9 organopolysiloxane 3 Tin catalyst 0.4 0.6 0.6 0.6 0.5 Acetylacetone 4.4 5.0 5.0 5.1 4.6 Xylene 0.9 2.3 2.3 2.2 1.3 Subtotal 13.6 16.0 16.0 16.1 13.9 Additive Aminosilane compound 0.1 0.1 0.1 0.1 0.1 component Xylene 0.8 2.9 2.9 3.0 0.8 (Z) Subtotal 0.9 3.0 3.0 3.0 0.9 Total 100.0 92.9 96.9 99.9 99.9 Properties of Immediately Sagging resistance 250 300 200 200 300 coatings after Critical wet film thickness fabrication prior to occurrence of sagging [μm] Stormer viscosity [KU] 69 79 76 76 78 After Sagging resistance 350 200 400 100 200 accelerated Critical wet film thickness stability prior to occurrence of test at 40° C. sagging [μm] for 50 days Stormer viscosity [KU] 67 77 >141 77 82 Adhesion Good Good Good Good Good Antifouling Static 3 months 0 5 4 5 5 properties immersion 6 months 1 5 5 5 5 9 months 0.5 5 5 5 5 12 months 0.5 4 5 4 4 Dynamic 3 months 0 3 3 1 1 immersion 6 months 0 5 5 5 5 9 months 0 1 4 2 2 12 months 0.5 5 5 5 5

(144) The results show that the antifouling coating compositions of the invention satisfy sprayability and sagging resistance in a balanced manner and can maintain these properties stably even after long storage.

(145) Further, the antifouling performance will be discussed with respect to the proportions of fouling by aquatic organisms including slime. As shown in Table 2, the coating films of Comparative Examples 1, 3 and 4 which did not contain any pyrithione metal salts and the coating film of Comparative Example 2 in which the pyrithione metal salt had been replaced by Irgarol suffered fouling at high proportions mainly due to the attachment of slime. In contrast, the coating films of Examples 1 to 11 which contained the pyrithione metal salt were demonstrated to exhibit high antifouling properties over long periods, permitting very little fouling. Further, this antifouling performance was displayed in both the static environment and the dynamic environment. These result shows that the inventive antifouling coating films can effectively exhibit antifouling performance under various conditions experienced by marine structures and marine vessels.