HK1099175B - Synergistic antifouling compositions comprising 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1h-pyrrole-3-carbonitrile - Google Patents

Description

Synergistic antifouling compositions containing 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile

The application is a divisional application of an invention patent application with the application date of 2002, 11/5 and the application number of 02821921. X.

Technical Field

The present invention relates to antifouling compositions and in particular to compositions which provide improved protection against fouling organisms. The present invention relates inter alia to a synergistic antifouling composition comprising at least 3.5 wt% based on dry weight of the composition of 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile or a salt thereof, and another biocide selected from bethoxazin, tolylfluanide, dichlorofluanide or DCOIT; as protective material against fouling organisms. The present invention therefore relates to the field of protection of materials, such as underwater objects, in relation to the protection of wood, wood products, biodegradable materials and coatings.

Background

4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile (known as component I) is disclosed in EP-0,312,723-A for controlling molluscs. The compound may be represented by the formula:

the component (II) comprises:

pyrtropioxazine (component II-a) is disclosed in WO-95/06043 as a bactericidal and fungicidal compound useful for wood protection and also in WO-95/05739 as having antibacterial, anti-fermentative, antifungal, algicidal, anti-crustacean and molluscicidal properties. Which is the common name for the compound 3- (benzo [ b ] thiophen-2-yl) -5, 6-dihydro-1, 4, 2-oxathiazine-4-oxide, which can be represented by the following formula

Tolylfluanide (component II-b) has an activity similar to that of dichlofluanide, but has a better solubility in organic solvents and is therefore easier to integrate into coating formulations and impregnants. Which is the common name for the compound 1, 1-dichloro-N- [ (dimethylamino) sulfonyl ] -1-fluoro-N- (4-tolyl) -methanesulfonamide, and can be represented by the formula

Dichlofluanid (component II-C) has broad-spectrum antimicrobial activity and is used in wood coatings and primers to combat wood-staining fungi. It is the common name for the compound 1, 1-dichloro-N- [ (dimethylamino) sulfonyl ] -1-fluoro-N-phenyl-methanesulfonamide, which can be represented by the formula

DCOIT (component II-d) is a broad-spectrum biostatic agent used in antifouling paints and wood preservatives. Which is the trivial name for the compound 4, 5-dichloro-2- (n-octyl) -3(2H) -isothiazolone, which can be represented by the formula

Compositions comprising component (I) as barnacidal agent together with an algicidal agent are disclosed in WO-98/12269.

Disclosure of Invention

It has now been found that a composition of 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile (hereinafter component I) with another biocide selected from betoxazine, tolylfluanid, dichlofluanid or DCOIT (hereinafter component II) provides a synergistic control of fouling organisms, especially algae, within the scope of the composition (i.e. the particular individual proportions or amounts of active ingredients) can be readily determined by the skilled person. The content of 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile in the antifouling composition of the invention is at least 3.5% by weight, based on the total weight of the dry weight of the composition.

The term "4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile" or component (I), component (II-a), component (II-b), component (II-c) or one of the components (II-d) is meant to include the compounds in the form of a base or a salt, the latter being prepared by reacting the base form with a suitable acid. Suitable acids include, for example, inorganic acids such as hydrohalic acids, i.e., hydrofluoric, hydrochloric, hydrobromic and hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, hypophosphorous acid, and the like; or organic acids such as, for example, acetic acid, propionic acid, glycolic acid, 2-hydroxypropionic acid, 2-oxopropionic acid, oxalic acid, malonic acid, succinic acid, (Z) -2-butenedioic acid, (E) -2-butenedioic acid, 2-hydroxysuccinic acid, 2, 3-dihydroxysuccinic acid, 2-hydroxy-1, 2, 3-propanetricarboxylic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, 4-methyl-benzenesulfonic acid, cyclohexanesulfamic acid, 2-hydroxybenzoic acid, 4-amino-2-hydroxybenzoic acid, and the like. The components (I) and (II) may also be in the form of solvates, such as hydrates.

Surfaces or objects exposed to moist or aqueous environments are prone to colonize by aquatic organisms such as algae, fungi, bacteria, microorganisms, and aquatic animals such as, for example, tunicates, hydroids, bivalves, bryozoans, polychaete worms, sponges, barnacles, mollusks, and crustaceans. As these organics settle or adhere to the surface, the value of the exposed article is reduced. The attachment or deposition of this organic matter is also referred to as "fouling" of the structure. The exterior or even the interior of the article is damaged, the surface changes, for example, from smooth, clean and streamline to rough, foul and turbulent, the weight of the article increases due to the deposited organic matter and its residues, and the vicinity of the article may become clogged or fouled with dirt. The function of the object and system under study is reduced and the quality of the water environment is compromised. A common method of controlling the attachment of fouling organisms is to treat the surface to be protected with a coating comprising an antifouling agent.

Fouling of surfaces or objects exposed to humid or aqueous environments often begins with the attachment or settlement of algae. This condition roughens the smooth surface, while other fouling organisms such as, for example, tunicates, barnacles, crustaceans, molluscs, etc. become easily sedimented. Therefore, the algicidal properties of antifouling compositions to protect surfaces from fouling are of major importance.

The composition of the invention is particularly suitable for protecting surfaces or objects which are in constant or frequent contact with water, against fouling or attachment or colonization by algae, by applying to said surface or object a synergistic antifouling composition comprising at least 3.5% by weight, based on the total dry weight of the composition, of one of component (I) and component (II), each in a proportion which provides a synergistic effect against fouling organisms. Examples of such surfaces or objects are, for example, ship hulls, estuary devices, wharfs and mortars, dry docks, water gates, mooring posts, buoys, off-shore drilling equipment, oil rigs, bridges, pipelines, fishing nets, cables, ballast tanks, ship tanks for pumping water from contaminated waters, recreational equipment such as surfboards, jet skis, and any other object that is in constant or frequent contact with water.

The invention also provides a method for protecting materials, especially surfaces or objects which are in constant or frequent contact with water, against fouling organisms by applying to the object an antifouling composition comprising an effective antifouling amount of at least 3.5% by weight, based on the total dry weight of the composition, of component (I) in combination with one of components (II), each in a ratio which provides a synergistic effect against fouling organisms.

The present invention also provides a method of protecting a surface comprising applying to the surface an anti-fouling composition of the present invention. Particularly important uses of the method of the invention include a method of inhibiting fouling of a ship's hull which comprises applying to the hull the antifouling composition of the invention. Fouling on the hull, for example, increases friction scraping, correspondingly reduces speed and maneuverability, and increases fuel consumption and maintenance costs by removing the fouling material.

Furthermore, the antifouling composition according to the present invention can be used for industrial immersion baths for protecting structures such as, for example, swimming pools, bathrooms, cooling water circulation conduits and various equipments whose functions are impaired by the presence and/or proliferation of fouling organisms, such as manufacturing plants or air-conditioning equipments. Other examples are buildings and building parts such as floors, exterior and interior walls or ceilings, or places that are prone to moisture such as cellars, bathrooms, kitchens, washing rooms, etc., and foul-smelling hotbeds. Foul smelling not only presents hygiene and aesthetic problems, but also results in economic losses because the building and/or finishing materials break down more quickly than expected.

The synergistic antifouling compositions of the invention can also be used in various applications:

industrial water treatment fluids such as cooling water, pulp mill process water and suspensions, secondary oil recovery systems, spinning fluids, metal treatment fluids and the like.

In-tank/in-can protection of aqueous functional fluids, such as polymer emulsions, water-based paints and adhesives, glues, starch slurries, thickening solutions, gelatins, wax emulsions, inks, polishes, pigments and inorganic slurries, rubber latexes, concrete additives, drilling muds, cosmetics, aqueous cosmetic formulations, pharmaceutical formulations, and the like.

"fouling organisms" include organisms that attach, settle, grow on or adhere to various surfaces, especially in humid or aqueous environments, such as sea water, fresh water, salt water, rain water, and cooling water, tap water, wastewater, and sewage. The fouling organism is an alga such as, for example, Microalgae (Microalgae), for example, euglena layer (Amphora), acrenstrum layer (Achnanthes), Navicula layer (Navicula), Navicula layer (ampiphora), bylonicera layer (melothrira), synechocystis layer (melosiara), ramosidium trae layer (coconeis), Chlamydomonas layer (Chlamydomonas), synechocystis layer (Chlorella), Chlorella layer (Ulothrix), candida pacifica layer (Anabaena), Phaeodactylum, haematococcus layer (Porphyridium), macroalgae such as phycophyta layer (Enteromorpha), nemacystus layer (Cladophora), trichotheca layer (ecotropha), trichotheca layer (acrochaeta), rhodophyta pellucium layer (cera), rhodophyta purpurea layer (echocarpus), rhodochrous layer (rhodophyta) and polynosium layer (polynosira); fungi; a microorganism; tunicates, including ascidiaceae such as Ciona intestinalis, Diposoma Listerianium, and Botrylus schlossiei; the hydroid net (Hydrozoa), including the Clava squamata; hydractinia echinata, Obeliagenonicula and Tubulararia laryux; binoculars including Mytilus edulis, Crassostravingica, Ostrea edulis, Ostrea chilennia, Dressena polymorpha (mussel (Zebra))), and Lasaea rubra; moss including electrora pilosa, Bugula neritina and bowenkia graminis; polychetes, including hydroids norvegica; sponge; and crustaceans, including Artemia and cirripdia (barnacles), such as Balanus amphitrite, Lepas ananatifer, Balanus, Balanus balanoids, Balanus hameri, Balanus crenatus, Balanus improvisus, Balanus galeatus, and Balanus eburneus; and Elminiusmodestus and Verruca.

The relative proportions of components (I) and (II) in the specific composition examples are such as to produce an unexpected synergistic effect against fouling organisms, especially against algae, compared to compositions comprising component (I) or component (II) active ingredient alone. It will be readily appreciated by those skilled in the art that such synergistic effects may be obtained at various ratios of components (I) to (II) in the composition, depending on the type of fouling organism for which the effect is being measured and the type of substrate to be treated. The determination of the synergistic or possibly (in terms of the partial ratio of components (I) to (II) applied to a particular fouling organism) non-synergistic effect of the composition is a routine task for a person skilled in the art, based on the teachings of the present application. However, for most fouling organisms, the appropriate weight ratio of component (I) to component (II) content in the active composition should generally be in the range of from 10: 1 to 1: 10. This range is preferably from 3: 1 to 1: 2, more preferably from 2: 1 to 1: 1. The specific ratio of the component (I) to the component (II) of the antifouling composition is 1: 1.

Particular compositions of the invention are those comprising at least 3.5% by weight of component (I) based on the total dry weight of the composition in combination with various proportions of component (II) selected from component (II-a) (i.e. pyridoxal) or component (II-b) (i.e. tolylfluanide), thereby providing a synergistic effect against fouling organisms.

Other specific compositions of the present invention are compositions comprising at least 3.5% by weight of component (I) based on the total dry weight of the composition in combination with various proportions selected from component (II-c) (i.e. dichlofluanid) or component (II-d) (i.e. DCOIT) to provide a synergistic effect against fouling organisms.

Very particular compositions of the present invention are compositions comprising at least 3.5% by weight of the total dry weight of the composition of a combination of component (I) and component (II-a), i.e. pyridoxazine, in various proportions to provide a synergistic effect against fouling organisms.

For safe treatment procedures against fouling organisms, the active components of components (I) and (II) used in the compositions of the invention should be present in essentially pure form, i.e. free from chemical impurities (such as by-products or residual solvents) generated during manufacture and/or handling. The active ingredients of components (I) and (II) used in the compositions of the invention, when they have at least one asymmetric carbon atom, may be in the form of a racemic mixture or in the form of substantially pure stereoisomers or enantiomers of the compound obtained from a racemic mixture by standard fractionation methods, including simulated moving bed techniques. The term "substantially pure" as used hereinbefore means a purity of at least about 96%, preferably at least 98%, more preferably at least 99%, as determined by methods conventional in the art, such as high performance liquid chromatography or optical methods.

The amounts of the active ingredients in the compositions of the present invention are such that a synergistic effect is obtained. In particular, the ready-to-use compositions of the present invention are believed to comprise at least 3.5% by weight of component (I), based on the total dry weight of the composition. More particularly, the ready-to-use composition comprises from 4% to 6% by weight of component (I), based on the total dry weight of the composition. The amount of component (II) in the ready-to-use composition is such that a synergistic effect is obtained. In particular, the content of component (II) ranges from 1 to 20% by weight, more particularly from 3.5 to 6% by weight, of the total dry weight of the composition. In many cases, the antifouling compositions to be used directly can be obtained from concentrates, such as, for example, emulsifiable concentrates, suspension concentrates, or soluble concentrates, by dilution with an aqueous or organic medium. These concentrates are encompassed by the term composition as used in the definition of the present invention. These concentrates can be diluted in a spray tank to a ready-to-use mixture immediately prior to use.

Thus, the combination of components (I) and (II) is suitable for use with carriers and additives, including wetting agents, dispersing agents, adhesives, sticking agents, emulsifying agents and the like, such as those conventionally used in the formulation art. The antifouling compositions according to the invention can be prepared in any known manner, for example by homogeneously mixing, coating and/or grinding the composition of the active ingredients, i.e. one of the components (I) and (II), and the selected carrier material, in a one-step or multistage process, and if appropriate further additives such as surfactants.

Examples of inert carrier materials suitable for use as solid carriers in the present invention-for example those used in powder concentrates and granular formulations include natural and synthetic mineral fillers, for example magnesium silicates such as talc; silica such as diatomaceous earth; aluminum silicates such as kaolin, montmorillonite or mica; magnesium aluminum silicates such as attapulgite and vermiculite; calcium carbonate and calcium sulfate; carbon such as charcoal; sulfur; and highly dispersed silicic acid polymers. Suitable particulate absorbent carrier materials may be porous, such as pumice, broken brick, sepiolite or bentonite. In addition, a large amount of pregranulated material of inorganic or organic nature can be used, such as, in particular, dolomite or ground plant residues. Other inert carrier materials suitable for use as organic solid carriers include natural and synthetic resins (crude or formulated), for example organic waste polymers such as polyvinyl chloride, polyethylene, polypropylene, polyacrylates such as polymethyl methacrylate, polystyrene and mixed polymers thereof.

Suitable surfactants for use in the antifouling compositions of the invention are nonionic, cationic and/or anionic materials having good emulsifying, dispersing and/or wetting properties. Suitable anionic surfactants include both water-soluble soaps and water-soluble synthetic surfactants. Suitable soaps are alkali metal or alkaline earth metal salts, unsubstituted or substituted higher fatty acids (C)₁₀-C₂₂) Ammonium salts, such as the sodium or potassium salts of oleic or stearic acid, or of natural fatty acid mixtures obtainable from coconut oil or tallow oil. Synthetic surfactants include sodium or calcium salts of polyacrylic acids; fatty sulfonates and sulfates; sulfonated benzimidazole derivatives and alkylaryl sulfonates. The fatty sulfonates or sulfates are generally in the form of alkali metal or alkaline earth metal salts, unsubstituted ammonium salts or ammonium salts substituted by alkyl or acyl radicals having from 8 to 22 carbon atoms, for example the sodium or calcium salts of lignosulfonic acid or dodecylsulfonic acid or fatty alcohol sulfonates obtained from natural fatty acids, alkali metal or alkaline earth metal salts of sulfuric or sulfonic acid esters (such as sodium lauryl sulfate) and sulfonic acid/ethylene oxide adducts of fatty alcohols. Suitable sulphonated benzimidazole derivatives preferably contain 8 to 22 carbon atoms. Examples of alkylaryl sulfonates are dodecylbenzenesulfonic acid or dibutylnaphthalenesulfonic acid orSodium, calcium or alkanolamine salts of naphthalene-sulfonic acid/formaldehyde condensation products. The corresponding phosphates are also suitable, for example the salts of phosphoric acid esters, and the adducts of p-octylphenol with ethylene oxide and/or propylene oxide, or phospholipids. Suitable phospholipids are synthetic phospholipids of the natural (from animal or plant cells) or cephalin or lecithin type, such as, for example, phosphatidylethanolamine, phosphatidylserine, phosphatidylglycine, lysolecithin, cardiolipin, dioctylphosphatidylcholine, dipalmitoylphosphatidylcholine and mixtures thereof.

Suitable nonionic surfactants include: polyethoxylated and polypropoxylated derivatives of alkylphenols, fatty alcohols, fatty acids, aliphatic amines or amides having at least 12 carbon atoms in the molecule, alkylarylsulfonates and dialkylsulfosuccinates, such as polyglycol ether derivatives of aliphatic and cycloaliphatic alcohols, saturated and unsaturated fatty acids and alkylphenols, which preferably contain 3 to 10 glycol ether groups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moiety and 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols. Other suitable nonionic surfactants are water-soluble adducts of polyethylene oxide with polypropylene glycol, ethylenediamine polypropylene glycol having from 1 to 10 carbon atoms in the alkyl chain, which adducts contain from 20 to 250 ethylene glycol ether groups and/or from 10 to 100 propylene glycol ether groups. The compounds typically contain 1 to 5 ethylene glycol units per propylene glycol unit. Representative examples of nonionic surfactants are nonylphenol polyethoxyethanol, castor oil polyglycol ether, polypropylene/polyethylene oxide adduct, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol. Fatty acid esters of polyethylene sorbitol (such as polyoxyethylene sorbitol trioleate), glycerol, sorbitol, sucrose and pentaerythritol are also suitable nonionic surfactants.

Suitable cationic surfactants are those comprising a quaternary ammonium salt, preferably a halide, having 4 hydrocarbyl groups optionally substituted with halo, phenyl, substituted phenyl or hydroxy; e.g. containing at least one C₈-C₂₂Alkyl radicals (e.g. cetyl, lauryl, palm)Mesityl, myristyl, oleyl, etc.) as N-substituent, and quaternary ammonium salts which are unsubstituted or halogenated with lower alkyl, benzyl and/or hydroxy-lower alkyl as a further substituent.

Further description of surfactants commonly used and suitable for this case can be found, for example, in the following publications:

“McCutcheon’s Detergents and Emulsifiers Annual”(MC Publishing Crop.，Ridgewood，New Jersey，1981)；“Tensid-Taschenbuch”，2^nded. (Hanser Verlag, Vienna, 1981) and "Encyclopaedia of Surfactants (Chemical Publishing Co., New York, 1980-.

Alternatively, the emulsifiable concentrate formulations of the present invention can be prepared by diluting the combination of components (I) and (II) with at least one suitable organic solvent (i.e., a liquid carrier) followed by the addition of at least one solvent-soluble emulsifier. Solvents suitable for such formulations are generally water-immiscible and belong to the classes of hydrocarbon, chlorinated hydrocarbon, ketone, ester, alcohol and amide solvents, which can be appropriately selected by the skilled person based on the solubility of components (I) and (II), respectively. Emulsifiable concentrates usually contain, in addition to the organic solvent, from about 10 to 50% by weight of the active ingredient combination, from about 2 to 20% of emulsifiers and up to 20% of other additives such as stabilizers, corrosion inhibitors and the like. The combination of components (I) and (II) may also be formulated as a suspension concentrate, which is a stable suspension of the active ingredients in a liquid, preferably organic, which is diluted with water before use. To obtain such a non-settling flowable product, it is generally necessary to incorporate therein up to about 10% by weight of at least one suspending agent selected from known protective colloids and thixotropic agents. Other liquid formulations like aqueous dispersions and emulsions, for example obtained by diluting a wettable powder or concentrate with water, such as the ones described above, and also water-in-oil or oil-in-water types, are also encompassed within the scope of the present invention.

The invention also provides protective compositions, for example in the form of paints, varnishes or varnishes, comprising the combination of the components (I) and (II) described together with one or more additives suitable for their formulation. The total amount of the combination of components (I) and (II) in the protective composition may be from 2 to 10% (w/v). Additives suitable for use in the protective composition are conventional in the art and include, for example, at least one organic binder (preferably in aqueous form), such as acrylic or ethylene-based emulsions or rosin compounds; surfactants such as those described in the foregoing formulation of agricultural compositions; a viscosity modifier; a corrosion inhibitor; pigments such as titanium dioxide; stabilizers such as sodium benzoate, sodium hexametaphosphate, and sodium nitrate; mineral or organic colorants, and the like. The manner of formulating the additives with active biological components such as those described herein is also well known to those skilled in the art. The protective composition not only can be used alone to eliminate and/or limit the damaging consequences of fouling organisms, but also can prevent materials from being damaged by harmful environments and from being affected by fouling organisms.

Other suitable additives for the antifouling compositions of the invention may be solid or liquid and are substances known in the art to be suitable for preparing formulations for surfaces or objects exposed to moisture or aqueous environments, providing further protective effects only for storage and handling. The additives may include, for example, polymers or copolymers, resins, and other optional additives such as drainage agents; a surface slip agent; a diluent; an organic binder; an insecticide; a fungicide; a bactericide; an auxiliary solvent; processing the additive; a fixative; a thickener; a plasticizer; a UV-stabilizer; stabilizers against heat or light; a dye; a coloring pigment; a desiccant; a corrosion inhibitor; an anti-settling agent; an anti-skinning agent; and defoaming agents and the like.

The antifouling compositions of the invention can be applied by a variety of conventional methods, such as hydraulic spraying, air blast spraying, aerosol spraying, dusting, spreading or pouring. The most suitable method is selected by those skilled in the art according to the desired purpose and the surrounding environment, i.e., the type of fouling organic matter to be controlled, the type of equipment used, and the type of material to be protected.

As previously mentioned, the combination of components (I) and (II) is preferably applied in the form of a composition in which the two components are sufficiently blended to ensure simultaneous application to the material to be protected. The application or application of the two components (I) and (II) can also be applied or applied "in combination" in succession, i.e.component (I) and component (II) are applied alternately or in succession or at the same point, so that they are necessarily admixed at the site to be treated. This effect is achieved if the administration is carried out sequentially within a short time, for example within 24 hours, preferably less than 12 hours. Such an alternative process can be carried out, for example, by using a suitable single package comprising at least one container filled with a formulation comprising active ingredient (I) and at least one container filled with a formulation comprising active ingredient (II). Thus, the invention also includes products comprising the following composition:

- (a) compositions comprising as component (I) at least 3.5% by weight, based on the total dry weight of the composition, of 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile, and

- (b) a composition comprising an active ingredient (II) selected from the group consisting of piroxazine, tolylfluanid, dichlofluanid or DCOIT, for simultaneous or sequential use, wherein the respective proportions of (a) and (b) provide a synergistic effect against fouling organisms, especially algae.

Detailed Description

The following examples are intended to illustrate the scope of the invention.

Examples

1. Poison culture dish assay in 96 well culture dish

Activity against algae growth was determined by a poison petri dish assay. Calculated amounts of stock solutions (containing 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile, pyridoxazine, DCOIT, dichlorfluanid or tolylfluanid in DMSO) were pipetted into a multi-well petri dish to reach final test concentrations of from 0.05ppm to 100ppm, mixed with warmed medium. The medium was inoculated with 300 microliters of algae suspension. The multi-well plates were maintained at 21 ℃, 65% relative humidity and 16 hour daily light-dark cycles (1000Lux photoperiod).

The lowest concentration of each test compound or mixture of test compounds sufficient to inhibit visible growth was taken as the Minimum Inhibitory Concentration (MIC). MIC was taken as the activity endpoint. The end point of the combination of component (I) with one of the components (II) is compared with the end point of the pure active compound used alone.

The synergistic use of component (I) with one of the components (II) is described by Kull F.C. et al in applied microbiology,9the commonly used and accepted method described in 538-541(1961) uses a synergyiindex assay calculated for both compounds a and B as follows:

synergy Index (SI) ═ Q_a/Q_A+Q_b/Q_B

Wherein

QA is the concentration (e.g. MIC) at which Compound A alone gives an endpoint, expressed in ppm

Qa is the concentration (e.g. MIC) at which compound a gives an endpoint when acted on in admixture, expressed in ppm,

QB is the concentration (e.g. MIC) at which Compound B alone gives an endpoint, expressed in ppm

Qb is the concentration (e.g. MIC) in ppm at which compound B gives an endpoint when it is allowed to act in admixture.

When the synergy index is more than 1.0, antagonism is exhibited. When SI is equal to 1.0, additivity is shown. Synergy was demonstrated when SI was less than 1.0.

Table 1: MIC-values (minimum inhibitory concentration in ppm) and synergy index (incubation time: 18 days) of the active ingredients and combinations thereof against Chlorella vulgaris (CCAP211/12)

	(I) To (II) ratio	MIC-value	Synergy index
				Ingredient (I)	Is single	100*	-
Component (II-a)	Is single	1.6	-
				(I)+(IIa)	1∶3	1.6	0.75
(I)+(IIa)	1∶1	3.1	0.98
				(I)+(IIa)	3∶1	6.2	1.02
Become intoPortion (I)	Is single	100*	-
				Component (II-b)	Is single	25	-
(I)+(II-b)	1∶3	12.5	0.41
				(I)+(II-b)	1∶1	25	0.63
(I)+(II-b)	3∶1	25	0.44
				Ingredient (I)	Is single	100*	-
Component (II-c)	Is single	25	-
				(I)+(IIc)	1∶3	25	0.81
(I)+(IIc)	1∶1	25	0.63
				(I)+(IIc)	3∶1	25	0.44
Ingredient (I)	Is single	100*	-

Ingredient (IId)	Is single	1.6	-
				(I)+(IId)	1∶3	1.6	0.75
(I)+(II-d)	1∶1	3.1	0.98
				(I)+(II-d)	3∶1	6.2	1.02

^*The MIC-value of component (I) for this organism is higher than 100ppm, but this value is used to calculate the SI.

Table 2: MIC-values (minimum inhibitory concentration in ppm) and synergy index (incubation time: 18 days) of various active ingredients and compositions thereof against (Bacillus subtilis) (CCAP379/1)

	(I) To (II) ratio	MIC-value	Synergy index
				Ingredient (I)	Is single	100*	-
Component (II-a)	Is single	6.2	-
				(I)+(II-a)	1∶3	6.2	0.77
(I)+(II-a)	1∶1	6.2	0.53
				(I)+(II-a)	3∶1	12.5	0.60
Ingredient (I)	Is single	100*	-
				Component (II-b)	Is single	12.5	-
(I)+(IIb)	1∶3	6.2	0.39
				(I)+(IIb)	1∶1	12.5	0.56
(I)+(IIb)	3∶1	12.5	0.34
				Ingredient (I)	Is single	100*	-
Component (II-c)	Is single	25	-
				(I)+(II-c)	1∶3	12.5	0.41
(I)+(II-c)	1∶1	12.5	0.31
				(I)+(II-c)	3∶1	12.5	0.22

Ingredient (I)	Is single	100*	-
				Component (II-d)	Is single	1.6	-
(I)+(II-d)	1∶3	1.6	0.75
				(I)+(II-d)	1∶1	1.6	0.51
(I)+(II-d)	3∶1	6.2	1.02

^*Component (I) to such an organic compoundMIC-values for subjects were higher than 100ppm, but this value was used to calculate SI.

2. Examples of antifouling paint

Examples 1 to 4 are conventional rosin-based anti-fouling compositions.

Rosin is a solid material, such as that naturally occurring in oleoresin of pine trees and is generally derived from oleoresin exudates of live trees, from old tree roots, and from tall rain oil as a by-product of kraft paper manufacture. Rosins are generally classified as rosin gum, wood rosin, and tall rain rosin, which represent their sources.

Claims (3)

1. Use of 4-bromo-2- (4-chlorophenyl) -5- (trifluoromethyl) -1H-pyrrole-3-carbonitrile as component (I) for synergistically improving the efficacy of DCOIT as component (II) against fouling organisms, wherein the weight ratio of component (I) to component (I I) is from 1: 1 to 1: 3.
2. 2. The use according to claim 1, wherein the amount of component (I) is 4 to 6% by weight based on the total dry weight of the composition comprising the combination of component (I) and component (I I).
3. 3. The use according to claim 1, wherein the amount of component (II) is from 3.5 to 6% by weight, based on the total dry weight of the composition comprising the combination of component (I) and component (II).