GB2255343A - Improvements relating to marine stainproofing agents - Google Patents

Abstract

A marine stainproofing agent comprises A) 4,5-dichloro-2-n-octylisothiazoline-3-one; B) a polymer comprising one or more monopolymers of unsaturated monomers having the formula (1), <IMAGE> wherein X is H or Me, n is an integer of 1-50, and R<1> is (C1-C18)alkyl or (C1-C18)acyl. or hydrophilic copolymers of other unsaturated monomers and the above monomers; C) one or more of: (i) at least one dialkylpolysulfide derivative of the formula (2> R<2>-(S)m-R<3> (2> wherein R<2> and R<3> are each independently (C1-C20)alkyl, and m is an integer of 1-5, (ii) a polybutene having a degree of polymerization of 2-100, (iii) a xylene/formaldehyde polycondensation product having an average molecular weight of 300-1000, or (iv) a C9 aromatic hydrocarbon/formaldehyde polycondensation product having an average molecular weight of 350-500. The agent has improved elution control, resulting in improved long-term activity.

Description

IMPROVEMENTS RELATING TO MARINE STAINPROOFING AGENTS Fishing nets for cultivation, fixed nets, materials such as ropes supporting them, and screens for preventing sea pollution used under coast constructions for example, remain immersed in seawater for long periods.

Because they become ultimatelv fouled by adhering marine organisms, problems such as mesh blockage, infectious or parasitic diseases of fish caused bv decreased seawater inflow, and damage or decreased buoyancy of the net due to increased weight can become significant.

To prevent nets from becoming fouled or stained by adhesive marine organisms a sea stainproofing treatment agent containing an organic tin compound such as TBT (tributvl tin compound) as active ingredient, has been widely used. Use of it, however, is becoming less popular due to accumulation of the active ingredient in the marine environment.

As an organic tin-free stainproofing agent, Japanese Patent Publication No. 43962/1987 discloses an dialkylsulfide compound, and Japanese Patent Laid-open No. 38306/1985 discloses using tetraalkylthiuramdisulfide, dial kylpol ysulfide, and 2-( thiocyanomethylthio)benzothiazole.

The present inventors have suggested a stainproofing agent for fishing nets containing a copolymer having specific hydrophilicity plus thiocyanoalkylthiobenzoheterozole, in Japanese Patent Laid-open No.

178562/1989.

Effective stainproofness cannot be obtained using only a dialkylsulfide compound, and although tetraalkylthiuramdisulfide, dialkylpolysulfide and 2-( thiocyanomethylthio)benzothiazole mentioned above have sufficient stainproofing activity in the short term, use of them alone does not allow the active ingredients to elute in a sufficient amount from the treatment agent to be of use in the long term. Furthermore, it was found that the combination of copolymer having specific hydrophilicity and thiocyanoalkylthiobenzoheterozole suggested by the present inventors was also inadequate to provide adequate stainproofing for long periods.

An object of the present invention is to provide a method for controlling the elution rate of a stainproofing agent from fibriform or corded materials treated therewith in order to improve the efficacy of said agent over long periods.

The present inventors have made a devoted study to accomplish the aforesaid object, and have determined that the elution rate of 4,5-dichloro-2n-octylisothiazoline-3-one as a stainproofing agent contained in a sea stainproofing treatment agent can be satisfactorily controlled for a long period by combining a specific hydrophilic polymer with a specific dialkylpolysulfide compound, a polybutene, a xylene/formaldehyde polycondensation product and/or a Ca aromatic hydrocarbon/formaldehyde polycondensation product.

Accordingly the present invention provides a marine stainproofing agent comprising A) 4,5-dichloro-2-n-octyliso thiazoline-3-one; B) a polymer comprising one or more monopolymers of unsaturated monomers having the formula (1),

wherein X is H or Me, n is an integer of 1-50, and Rl is (C1-Cls)alkyl or (C1 -C18)acyl, or hydrophilic copolymers of other unsaturated monomers and the above monomers; C) one or more of:: (i) at least one dialkylpolysulfide derivative of the formula (2) R2-(S)m-R3 (2) wherein R2 and R3 are each independently (C1 -C20)alkyl, and m is an integer of 1-5, (ii) a polybutene having a degree of polymerization of 2-100, (iii) a xylene/formaldehyde polycondensation product having an average molecular weight of 300-1000, or (iv) a C9 aromatic hydrocarbon/ formaldehyde polycondensation product having an average molecular weight of 350-700.

In a further aspect the invention comprises a method of controlling the elution rate of 4,5-dichloro-2-n-octylisothiazoline-3-one as a stainproofing agent from fibriform or corded materials immersed in seawater, comprising incorporating with said agent components B) and C) as defined above. The invention also encompasses a method of protecting a fibriform or corded material immersed in seawater from staining by marine organisms, comprising impregnating said material with a stainproofing agent as defined above; and in a further aspect it includes the use of components B) and C) as defined above to control the elution rate of a stainproofing agent 4,5-dichloro 2-n-octvlisothiazoline-3-one from fibriform or corded materials immersed in seawater.

Component A), 4,5-dichloro-2-n-octylisothiazoline-3-one, is known as a stainproofing agent having low toxicity.

Component B used as an elution controller comprises a polymer of either a unit B1 consisting of one or more unsaturated monomers having the aforesaid formula (1), or a unit B2 consisting of one or more of unit B1 and one or more unsaturated monomers copolymerizable with the unit BI.

The unit B1 consists of, for example, 2-methoxyethyl acrylate, methoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxytetraethylene glycol acrylate, methoxypolyethylene glycol acrylate, 2ethoxyethyl acrylate, ethoxydiethylene glycol acrylate, ethoxytriethylene glycol acrylate, ethoxytetraethylene glycol acrylate, ethoxypolyethylene glycol acrylate, 2-propoxyethyl acrylate, propoxydiethylene glycol acrylate, propoxytriethylene glycol acrylate, propoxytetraethylene glycol acrylate, propoxypolyethylene glycol acrylate, 2-acetoxyethyl acrylate, acetoxydiethylene glycol acrylate, acetoxytriethylene glycol acrylate, acetoxytetraethylene glycol acrylate, acetoxypolyethylene glycol acrylate, 2-methoxyethyl methacrylate, methoxydiethylene glycol methacrylate, methoxytriethylene glycol methacrylate, methoxytetraethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, 2-ethoxyethyl methacrylate, ethoxydiethylene glycol methacrylate, ethoxytriethylene glycol methacrylate, ethoxytetrae thylene glycol methacrylate, ethoxypolyethylene glycol methacrylate, 2-propoxyethyl methacrylate, propoxydiethylene glycol methacrylate, propoxytriethylene glycol methacrylate, propoxytetraethylene glycol methacrylate, propoxypolyethylene glycol methacrylate, 2-acetoxyethyl methacrylate, acetoxydiethylene glycol methacrylate, acetoxytriethylene glycol methacrylate, acetoxytetraethylene glycol methacrylate, or acetoxypolyethylene glycol methacrylate.

The unit B2 includes, for example, alkyl acrylate, alkyl methacrylate, crotonic ester, itaconic ester, acrylamide, acrylonitrile, ethylene, vinyl chloride, vinyl acetate, vinylidene chloride, methyl vinyl ether, butadiene, cyclohexene, styrene, vinyltoluene, alpha-methylstyrene, and chlorostyrene.

The ingredient C contained in the sea stainproofing treatment agent used in the present invention consists of one or more compounds selected from the aforesaid C(i)-C(iv).These components are usually used as extreme pressure agents for cutting oil, resin softeners, seizes, etc., and do not influence any organisms.

The component C(i) is, for example, di-tert-nonylpentasulfide (specific gravity is 1.03) or di-tert-dodecylpentasulfide (specific gravity is 1.55). A polybutene of the component C(ii) is, for example, various kinds of Nissanpolybutene (Polybis) (manufactured by Nihon Yushi K.K.), a xylene/formaldehyde polycondensation product of the component C(iii) is, for example, various kinds of Oregotech (manufactured by Mitsubishi Sekiyu K.K.), and a C9 aromatic hydrocarbon/formaldehyde polycondensation product of the component C(iv) is, for example, various types of Generite (manufactured by General Sekiyu Kagaku K.K.). The components C are, however, not limited to the above materials.

The blending ratios of the components A-C in 100 parts by weight of the sea stainproofing agent used in the present invention are 0.3-20 parts by weight, preferably 0.5-20 parts bv weight of the component A, 1-30 parts by weight, preferably 2-20 parts by weight of the component B, 1-30 parts by weight, preferably 2-25 parts by weight of the component C, and what is left is another component such as an organic solvents.

The stainproofing tends to be inadequate if the amount of component A is below the bottom limit, and coating of the net can be insufficient if the amount of component A exceeds the above upper limit or the amount of component B is below the above lower limit. When the component B is present at above the upper limit, problems of insufficient stainproofing or decreased elution control can occur. Decreased elution control may also occur if component C is present in insufficient amounts, and coating may be inadequate if there is too much of component C.

The marine stainproofing treatment agent used in the present invention can additionally include other materials such as resins, organic solvents, further stainproofing agents, colourants, additives, agents for thixotropy, anti-form agents, thickening agents, or plasticizers besides the aforementioned components A-C.

Examples of other resins are rosin, modified rosin, fatty acids, usual oil varnish, chlorinated rubbers, polyvinyl chlorides, styrene/butadiene copolymers, and acrylate resins.

Examples of organic solvents are toluene, xylene, solvent naptha, pseudocumene, acetone, ethvl methyl ketone, isobutyl methyl ketone, ethyl acetate, butvl acetate, alkyl cellosolve, etc., or a mixture thereof.

As additional stainproofing agents may be used any of: N-tert-butyl-N' cyclopropyl-6-(methylthio)-1 ,3,5-triazine-2,4-diamine, 3-(3,4-dichlorophenyl)1,1 -dimethylurea, N,N-dimethyl-N'-phenyl-N'-(fluorodichloromethylthio) sulfamide, N,N-dimethyl-N'-triyl-N'-(fluorodichloromethylthio) sulfamide, N-(fluorodichloromethylthio)phtalimide, bis(diethylcarbamoyl)disulfide, 2 (thiocyanomethylthio) benzothiazole, 2,4,5,6-tetrachloro-1 ,3-dicyanobenzen, N-2,6-diethylphenyl)dichloromaleimide, N-(2-ethyl-6methylphenyl)dichloromaleimide, copper suboxide, an organic tin compound, zinc dimethyldithiocarbamate, copper diethyldithiocarbamate, tetraethylthiuramdisulfide, N-(ethylmethylphenyl)-dichloromaleimide, or N (diethylphenyl)-dichloromaleimide.

The marine stainproofing agent of the present invention is usually prepared by dissolving the ingredients in an organic solvent using a solubilizer. Impregnation of a net is accomplished by usual methods such as soaking.

EXAMPLES The present invention is embodied by the following examples and comparative experiments, wherein parts and % are based on weight.

COMPOSITIONS 1-3 According to the blending ratio shown in Table 1, the solvent 1, the unit Bl, the unit B2 and the catalvst 1 were charged into a flask having a stirrer, warmed to lOO0C in 30 minutes while stirring, and continuously stirred for a further 2 hours at the same temperature. Then an additional solution consisting of the solvent 2 and the catalyst 2 was added dropwise into the above mixture over 1 hour, and the mixture was stirred for 2 hours at 105"C and another I hour at 1200C.

Finally a diluting solvent was added and the mixture was homogenized. Thus 3 kinds of transparent hydrophilic copolymer solutions were obtained by the above procedure. The solids contents, the viscosities, and the molecular weights of these polymer solutions are shown in Table 1.

TABLE 1 Production 1 2 3 Solvent 1 xylene 60 60 60 Unit B1 ethoxypentadecaethylene 10 glycol methacrylate methoxytricosaethylene 5 2 glycol methacrylate 2-methoxyethyl acrylate 3 propioxytetradiethylene 21.5 glycol methacrylate 2-acetoxyethyl acrylate 21.4 Unit i32 methvl methacrylate 35 30 50 l-butvl methacrylate 50 22.1 2-ethylhexyl acrylate 45 st vrene 5 Catalyst 1 tert-butylperoxy-2- 1.5 ethylhexanoate benzoylperoxide 1.5 1.5 Catalyst 2 tert-butylperoxy-2- 0.5 ethylhexanate benzoylperoxide 1.5 1.5 Solvent 2 xvlene 20 20 20 Diluting xylene 20 20 20 solvent Property viscosity (poise/20 C) 1.3 1.0 1.2 value solids contents (weight %) 62.0 49.2 48.8 weight-average molecular 73,000 23,000 28,000 weight Examples 1-30 and Comparative Experiments 1-20 < Preparation of the Sea Treatment Agent > According to the blending ratio shown in Table 2, all the ingredients were charged into a beaker and dissolved by stirring with a dissolver for preparation of each sea treatment agent of examples and comparative experiments.

TABLE 2(1 /44/4) According to the methods disclosed below, the stainproofness against soak in the sea and the elution rate of each stainproofing agent of the examples and comparative experiments prepared by the above- mentioned procedures were examined. The results are shown in Table 3.

< Examination of Stainproofness > The samples, 20 cm wide and 40 cm long, of a fishing net (32, 6 joints) not having knots and made of polyethylene for cultivation growth were soaked into the sea stainproofing treatment agents of the examples and comparative experiments respectively to be impregnated, and air-dried for 48 hours. The samples were soaked at 1.5 m under the sea surface in Aioi Harbor, Hyogo prefecture, and examined on their states of stain by adhesive sea organisms for 6 months. The results of examination of stainproofness were shown with the following 5 levels.

5: No organism was adhered.

4: Adhered organisms were less than 5% by area based on the sample.

3: Adhered organisms were 5% or more to less than 15% by area based on the sample.

m Adhered organisms were 15% or more to less than 50% by area based on the sample.

1: Adhered organisms were 50% or more by area based on the sample.

< Elution rate of stainproofing agent > The same samples as those used in the examination of the stainproofness were impregnated with the sea treatment agents by the same methods and examined in the sea by the same methods. The samples impregnated with seawater were pulled up after 6 months and soaked in 1 liter of seawater in a beaker for elution of the stainproofing agents. The solution rates of the stainproofing agents were determined by analyzing the seawater including the stainproofing agents which eluted from the samples.

The elution rates were shown with the concentration of eluting the stainproofing agents in 1 liter of seawater (ppm).

TABLE 2-1/4 Example 1 2 3 4 5 6 7 8 9 10 11 12 DCOITO-1 66.7 66.7 66.7 66.7 66.7 66.7 66.7 66.7 66.7 66.7 66.7 66.7 Production 1 20.0 20.0 20.0 20.0 Production 2 24.8 24.8 24.8 24.8 Production 3 24.8 24.8 24.8 24.8 acrylate resin-2 TNPS-3 8.5 8.5 8.5 PB-4 8.5 8.5 8.5 XF-5 8.5 8.5 8.5 HCF-6 8.5 8.5 8.5 xylene 4.8 4.8 4.8 4.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 TOTAL 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 TABLE 2-2/4 Example 13 14 15 16 17 18 19 20 21 22 23 24 DCOITO-1 33.3 33.3 33.3 33.3 33.3 33.3 33.3 33.3 33.3 33.3 33.3 33.3 Production 1 8.1 8.1 8.1 8.1 Production 2 10.0 10.0 10.0 10.0 Production 3 10.0 10.0 10.0 10.0 acrylate resin-2 TNPS-3 10.0 10.0 10.0 PB-4 10.0 10.0 10.0 XF-5 10.0 10.0 10.0 HCF-6 10.0 10.0 10.0 xylene 48.6 48.6 48.6 48.6 46.7 46.7 46.7 46.7 46.7 46.7 46.7 46.7 TOTAL 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 TABLE 2-3/4 Example Comparative Experiment 25 26 27 28 29 30 1 2 3 4 5 6 DCOITO-1 50.0 50.0 50.0 50.0 50.0 50.0 Production 1 20.0 20.0 20.0 20.0 Production 2 24.8 24.8 24.8 24.8 24.8 24.8 24.8 24.8 Production 3 acrylate resin-2 TNPS-3 5.0 5.0 5.0 5.0 5.0 2.5 10.0 10.0 PB-4 5.0 2.5 2.5 2.5 10.0 10.0 XF-5 5.0 2.5 2.5 10.0 HCF-6 5.0 2.5 2.5 10.0 xylene 15.2 15.2 15.2 15.2 15.2 15.2 70.0 70.0 70.0 70.0 65.2 65.2 TOTAL 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 TABLE 2-4/4 Comparative Experiment 7 8 9 10 11 12 13 14 15 16 17 18 19 20 DCOITO-1 33.3 33.3 33.3 33.3 33.3 33.3 33.3 33.3 Production 1 16.1 Production 2 24.8 24.8 20.0 Production 3 24.8 24.8 24.8 24.8 20.0 acrylate resin-2 20.0 20.0 20.0 20.0 20.0 TNPS-3 10.0 10.0 PB-4 10.0 10.0 XF-5 10.0 10.0 10.0 HCF-6 10.0 10.0 10.0 xylene 65.2 65.2 65.2 65.2 65.2 65.2 36.7 36.7 36.7 36.7 50.6 46.7 46.7 46.7 TOTAL 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Note) (*1) DCOITO 4,5-dichloro-2-n-octylisothiazolin-3-one 30% xylene solution (Manufactured by Rohm and Haas) (*2) acrylate resin Hitaroide 1641A (Manufactured by Hitachi Kasei Kogyo K.K.) (Solids content 100%) (*3) TNPS di-tert-nonylpentasulfide (reagent; manufactured by Tokyo Kasei Kogyo K.K.) (*4) PB polybutylene 06N (Manufactured by Nihon Yushi K.K.) (*5) xylene/formaldehyde polycondensation product OLIGOTECH (Manufactured by Mitsubishi Sekiyu K.K.) (*6) HCF C9 hydrocarbon/formaldehyde resin ZENELITE (Manufactured by General Sekiyu Kagaku Kogyo K.K.) TABLE 3-1 Result of the examination Amount of eluting of s tainproofness s tainproofing ingredient 1 month 3mths 6mths ppm Example 1 5 5 5 0.23 2 5 5 5 0.19 3 5 5 5 0.18 5 5 5 5 0.20 5 5 5 5 0.14 6 5 5 5 0.13 7 5 5 5 0.13 5 0.15 9 5 5 5 0.12 10 5 5 5 0.12 11 5 5 5 0.10 12 5 5 5 0.11 13 5 5 5 0.12 14 5 5 5 0.10 15 5 5 5 0.09 16 5 5 5 0.09 17 5 5 5 0.08 18 5 5 5 0.06 19 5 5 5 0.07 20 5 5 5 0.06 21 5 5 5 0.06 22 5 5 5 0.07 23 5 5 5 0.06 24 5 5 5 0.08 25 5 5 5 0.25 26 5 5 5 0.16 TABLE 3-2 Result of the examination Amount of eluting of stainproofness stainproofing ingredient 1 month 3mths 6mths ppm Example 27 5 5 5 0.18 28 5 5 5 0.18 29 5 5 5 0.14 30 5 5 5 0.15 1 1 1 1 0 Comparative 2 1 1 1 0 experiment 3 1 1 1 0 4 1 1 1 0 5 1 1 1 0 6 1 1 1 0 7 1 1 1 0 8 1 1 1 0 9 1 1 1 0 10 1 1 1 0 11 1 1 1 0 12 1 1 1 0 13 4 2 1 0 14 4 2 1 0 15 4 2 1 0 16 4 2 1 0 17 5 2 1 0 18 5 1 1 0 19 5 1 1 0 20 3 1 1 0 Table 3 shows that the method for controlling the elution rates of stainproofing agents according to this invention provides good stainproofness and retains high elution rates of the stainproofing agents after 6 months as indicated in examples 1-3, showing the method is obviouslv superior.

Although specific embodiments and examples have been described herein, it should be born in mind that these have been provided by way of explanation and illustration and that the present invention is not limited therebv. Modifications which are within the ordinarv skill in the art to make are considered to lie within the scope of the invention as defined bv the following claims, including all equivalents.

Claims (14)

CLAIMS:

1. A marine stainproofing agent comprising A) 4,5-dichloro-2-n-octylisothiazoline-3-one; B) a polymer comprising one or more monopolymers of unsaturated monomers having the formula (1),

wherein X is H or Me, n is an integer of 1-50, and R1 is (Cl-Cl8)alkyl or (C1-C18)acyl, or hydrophilic copolymers of other unsaturated monomers and the above monomers; t) one or more ot:: (i) at least one dialkylpolysulfide derivative of the formula (2) R2(S)rnR3 (2) wherein R2 and R are each independently (C1 -C20)alkyl, and m is an integer of 1-5, (ii) a polybutene having a degree of polymerization of 2-100, (iii) a xylene/formaldehyde polycondensation product having an average molecular weight of 300-1000, or (iv) a C9 aromatic hydrocarbon/formaldehyde polycondensation product having an average molecular weight of 350-700.

2. Stainproofing agent according to claim 1 wherein polymer B) is a monopolymer of 2-methoxyethyl acrylate, methoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxytetraethylene glycol acrylate, methoxypolyethylene glycol acrylate, 2-ethoxyethyl acrylate, ethoxydiethylene glycol acrylate, ethoxytriethylene glycol acrylate, ethoxytetraethylene glycol acrylate, ethoxypolyethylene glycol acrylate, 2-propoxyethyl acrylate, propoxydiethylene glycol acrylate, propoxytriethylene glycol acrylate, propoxytetraethylene glycol acrylate, propoxypolyethylene glycol acrylate, 2acetoxyethyl acrylate, acetoxydiethylene glycol acrylate, acetoxytriethylene glycol acrylate, acetoxytetraethylene glycol acrylate, acetoxypolyethylene glycol acrylate, 2-methoxvethvl methacrylate, methoxydiethylene glycol methacrylate, methoxvtriethvlene glycol methacrylate, methoxytetraethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, 2-ethoxyethyl methacrylate, ethoxydiethylene glycol methacrylate, ethoxytriethylene glycol methacryl ate, e thoxy tetraethylene glycol methacrylate, ethoxypolyethylene glycol methacrylate, 2-propoxyethyl methacrylate, propoxydiethylene glycol methacrylate, propoxytriethylene glycol methacrylate, propoxytetraethylene glycol methacrylate, propoxypolyethylene glycol methacrylate, 2-acetoxyethyl methacrylate, acetoxydiethylene glycol methacrylate, acetoxytriethylene glycol methacrylate. acetoxytetraethylene glycol methacrylate, or acetoxypolyethylene glycol methacrylate.

3 Stainproofing agent according to claim 1 wherein polymer B) is a copolvmer (l a monomer as defined in claim 2 and alkyl acrylate, alkyl methacrvlate, crotonic ester, itaconic ester, acrylamide, acrylonitrile, ethylene, inyl cliorid. vinyl acetate, vinylidene chloride, methyl vinyl ether, butadiene, cyclohexane, stvrene, vinvltoluene, alpha-methylstyrene, or chlorostirene.

4. Stainproofing agent according to any preceding claim wherein the dialkylpolysulfide derivative of the formula (2) is di-tert-nonylpentasulfide (specific gravity 1.03) or di-tert-dodecylpentasulfide (specific gravity 1.55).

5. Stainproofing agent according to any preceding claim wherein the polybutene C(ii) is Nissanpolybutene.

6. Stainproofing agent according to any preceding claim wherein the xylene / formaldehyde polycondensation product is Oregotech.

7. Stainproofing agent according to any preceding claim wherein the C9 aromatic hydrocarbon/formaldehyde polycondensation product is Generite.

8. Stainproofing agent according to any preceding claim wherein the amounts of components A), B) and C) in 100 parts by weight of said agent are 0.3-20 parts A), 1-30 parts B), and 1-30 parts C), the balance being solvents and/or other additives.

9. Stainproofing agent according to claim 8 wherein the amounts of A), B) and C) are 0.5-20 parts A), 2-20 parts B) and 2-25 parts C).

10. Method of controlling the elution rate of 4,5-dichloro-2-noctylisothiazoline-3-one as a stainproofing agent from fibriform or corded materials immersed in seawater comprising incorporating with said agent B) a polymer comprising one or more monopolymers of unsaturated monomers having the formula (1),

wherein X is H or Me, n is an integer of 1-50, and R1 is (Cl-Cls)alkyl or (C1 -C18)acyl, or hydrophilic copolymers of other unsaturated monomers and the above monomers; and C) one or more of: (i) at least one dialkylpolysulfide derivative of the formula (2) Ix2-(S)m-Ra (2) wherein R2 and RS are each independently (C1 -C2o)alkyl, and m is an integer of 1-5, (ii) a polvbutene having a degree of polymerization of 2-100, (iii) a xvlene/formaldehvde polycondensation product having an average molecular weight of 300-1000, or (iv) a C9 aromatic hydrocarbon / formaldehyde polycondensation product having an average molecular weight of 350-700.

11. Method according to claim 10 wherein components B) and C) are as defined in any of claims 2 to 7.

12. Method of protecting a fibriform or corded material immersed in seawater from staining by marine organisms, comprising impregnating said material with a stainproofing agent as defined in any of claims 1 to 9.

13. Use of components B) and C) as defined in any of claims 1 to 7 to control the elution rate of a stainproofing agent 4,5-dichloro-2-noctylisothiazoline-3-one from fibriform or corded materials immersed in seawater.

14. Marine stainproofing agent substantially as hereinbefore described.