JPH08302247A - Aqueous biofouling preventing conductive composition and antifouling method using the same - Google Patents

Abstract

(57) [Summary] [Object] To provide a conductive composition for forming a conductive resin layer in the electrochemical control of aquatic organisms, and an antifouling method using the same. A conductive composition for forming a resin layer having conductivity for preventing adhesion of aquatic organisms, which comprises at least a binder resin, a conductive filler and an antibacterial substance Preventive conductive composition. The conductive resin layer formed on at least the contact surface with water contains at least a binder resin, a conductive filler and a substance having antibacterial properties, and the conductive resin layer has a positive potential or a negative potential or a positive potential and a negative potential. An antifouling method using a conductive composition for preventing adhesion of aquatic organisms to which an electric potential is alternately applied. [Effect] By applying an electric potential to the conductive resin containing the antibacterial agent, it is possible to sterilize or desorb marine-adhering bacteria adhering to the surface of the conductive resin, and also to locally non-conduct the conductive resin surface. Since the aquatic organisms attached to the sexual part are sterilized by the action of the antibacterial agent, it is possible to prevent the formation of slime layers and microbial layers by the aquatic organisms, and to prevent the attachment of large organisms. It is possible to prevent the stain-proofing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a conductive resin layer on the surface of an underwater structure such as a water conduit, a pipeline, a ship, a buoy, a port facility, a bridge, a fixed net or aquaculture net such as aquaculture cage of a power plant. And a positive potential or a negative potential, or a positive potential and a negative potential are alternately applied to the conductive resin layer periodically to sterilize or desorb aquatic organisms to prevent the adhesion. The present invention relates to a composition and an antifouling method using the same.

[0002]

2. Description of the Related Art Conventionally, for example, an antifouling means for introducing a seawater in order to use the seawater as a cooling water in a power plant, a ship, or a fishing net used in the seawater,
A method of adding a bactericidal substance such as hypochlorite to seawater to sterilize aquatic organisms, or a coating containing an organic tin compound to form a coating film on ships and fishing nets A method for preventing stains by elution is generally used. However, when a substance having bactericidal properties such as hypochlorite is added, it reacts with organic substances in seawater to generate harmful substances such as trihalomethanes, which may cause pollution of the ocean and influence on useful marine organisms. . Further, the use of organotin compounds is limited due to the problem of marine pollution. Further, non-organotin compounds are used as an alternative to the organic tin antifouling agents, but these alternative antifouling agents require a repainting of the paint because the retention time of the antiadhesive effect is short. There was a problem that the labor required for the repainting work was significantly increased and a large amount of labor cost was required.

Further, a method of decomposing seawater by an electrolytic reaction to generate chlorine and antifouling with these toxic substances has also been proposed, but a structure formed of metal such as a ship is corroded by chlorine. However, there is room for improvement in terms of practicality.

On the other hand, there has been proposed a method for electrochemically controlling aquatic organisms attached to ships and fishing nets without generating harmful substances such as chlorine. This method is a method utilizing the principle of attachment of aquatic organisms, and as a specific method,
Chloroprene rubber, silicone resin, urethane resin, acrylic resin, etc. as a conductive composition filled with a conductive material such as graphite in a coating material such as a binder, the conductive composition is coated on the surface of the underwater structure, A conductive resin layer is formed, and a positive potential at which chlorine is not generated by an electrolytic reaction of seawater, or a positive potential and a negative potential are alternately applied to the conductive resin layer,
It disinfects aquatic organisms adhering to the surface of a conductive resin and then removes them to make an underwater structure antifouling. That is, in this method, generally, the mechanism by which aquatic organisms attach to underwater structures is that adherent Gram-negative bacteria attach to the surface and secrete slime-like substances derived from lipids, and collect and grow in this slime layer. However, focusing on the fact that it is caused by the adherence of large-scale aquatic organisms such as algae, shellfish, and barnacles on the microbial layer, the aqueous phase of early Gram-negative bacteria It is intended to prevent the attachment of large-scale aquatic organisms by controlling the attachment of organisms.

[0005]

The above-mentioned method utilizing the principle of adhesion of aquatic organisms is formed by filling a conductive material in a binder resin such as chloroprene rubber or silicone resin, urethane resin, acrylic resin, which is an insulator. The conductive resin layer has conductivity, but non-conductive portions are partially formed on the surface of the conductive resin depending on the dispersed state of the conductive material, the conditions for forming the resin layer, and the like. The aquatic organisms attached to this non-conductive part cannot be controlled electrochemically, and a slime layer is locally formed, and then a microbial layer is formed. Furthermore, since large-sized aquatic organisms adhere to the formed microbial layer, there is a problem that the maintenance time of the anti-adhesion effect is shortened, leaving room for improvement.

The present invention has been made in view of the above problems, and provides a conductive composition for forming a conductive resin layer in the electrochemical control of aquatic organisms, and an antifouling method using the same. A conductive composition for forming a resin layer having conductivity for the purpose of preventing the adhesion of aquatic organisms, which is composed of at least a binder resin, a conductive filler, and an antibacterial substance. The first gist is a conductive composition for preventing biofouling, and in the first gist,
The second gist is an electrically conductive composition for preventing aqueous organism adhesion, wherein the substance having antibacterial properties is an inorganic substance or an organic substance. In the first gist, the substance having antibacterial properties is composed of a simple metal, a metal compound or an organic substance. A third aspect of the present invention is an electrically conductive composition for preventing adhesion of aqueous organisms, which comprises an inorganic substance carrying an antibacterial substance, wherein at least the electrically conductive resin layer formed on the contact surface with water is electrically conductive with at least the binder resin. A conductive composition for preventing adherence to aquatic organisms, comprising a filler and a substance having antibacterial properties, characterized in that a positive potential or a negative potential or a positive potential and a negative potential are alternately applied to the conductive resin layer thereof An antifouling method is the fourth gist, and in the fourth gist, an antifouling method using an electrically conductive composition for preventing the adherence of aquatic organisms, wherein the antibacterial substance is an inorganic substance or an organic substance, is the fifth gist. Summary of 4 The antifouling method using the conductive composition for preventing the attachment of aqueous organisms, wherein the antibacterial substance is a simple metal, a metal compound or an organic substance, and the antibacterial substance is carried on an inorganic substance. It is a summary.

The present invention will be described in more detail below. The binder resin used in the present invention is a thermoplastic resin, a resin that is dried or reacted and cured at room temperature, or a resin that is cured by heating, and may be an organic solvent type, a water-soluble type, or an emulsion type resin. . Examples of the thermoplastic resin or the cured resin that is dried or reacted at room temperature include natural rubber, NBR, SBR, chloroprene rubber, acrylonitrile butadiene rubber, ethylene propylene rubber, polyvinyl chloride resin, silicone resin, fluorine resin, polyethylene and polyethylene elastomer resin. , Polypropylene and polypropylene elastomer resin, urethane and urethane elastomer resin, polyvinyl acetate resin, vinyl acetate
Examples thereof include acrylic copolymer resin, polyamide resin, and polyimide resin.

As the resin which is cured by heating, thermosetting acrylic resin, melamine resin, urethane resin, tar modified urethane resin, epoxy resin, unsaturated polyester resin, polyester modified fluorine resin, silicone resin, alkyd resin, etc. Is mentioned. Further, it is more preferable to use a resin having high hydrophobicity in order to suppress the adhesion of aquatic organisms.

Next, the conductive filler will be described. Examples of the conductive filler include carbon materials such as carbon black, graphite and acetylene black, metal materials such as gold, silver, palladium, nickel, stainless steel and copper, tin oxide, indium oxide, antimony oxide, iron oxide and manganese. One kind of oxide or a mixture of two or more kinds of oxides is used. In addition, these conductive fillers are resin powders such as mica, nylon resin, polystyrene resin, polyethylene resin, silicone resin, acrylic resin, and oxide powders such as alumina, titanium oxide, silicon oxide, etc. It may be powder. Various shapes such as amorphous, spherical, scale-like, and fibrous can be used as the shape of these conductive fillers. Also, the particle size is from 0.01 μm to 200 μm
It only has to be about. The conductive filler is preferably filled in an amount of 20 to 60% by weight based on the binder-resin solid content.

Further, the substance having antibacterial properties will be described. Examples of the substance having antibacterial properties include inorganic substances and organic substances. Examples of the inorganic substances include silver, copper, nickel, zinc,
Metals such as lead and germanium, which are oxides, oxyacid salts, chlorides, sulfates, nitrates, carbonates, organic chelates
The compound may be a compound. As an organic substance, 2-
(4-thiazolyl) -benzimidazole, 4,5,
6,7-tetrachloro-2-trifluoromethylbenzimidazole, 10,10'-oxysphenoxyarsine, trimethoxysilyl-propyrioctadecyl ammonium chloride, 2-N-octyl-4-isothiazolin-3-one, Examples include bis (2-pyridylthio-1-oxide) zinc.

These antibacterial substances may be used alone or in admixture of two or more, and may be filled in an amount of about 0.00001 to 10% by weight based on the resin solid content in the conductive composition. 1-5% by weight should be contained,
Further, in order to maintain the antibacterial action for a long time, it is more preferable that an inorganic substance having an ion-exchange ability and an adsorptivity is loaded with a substance having antibacterial properties and filled in the conductive composition. As the inorganic substance having ion exchange ability and adsorptivity, alumina, zeolite, hydroxyapatite, activated carbon, silica or silica gel, calcium phosphate, zirconium phosphate,
Preferred are magnesium aluminometasilicate, calcium aluminometasilicate, calcium silicate, magnesium aluminate, calcium aluminate, potassium titanate, calcium titanate and the like. The shape of these inorganic substances is not limited, and the particle size may be about 0.1 to 200 μm. In addition, two or more kinds of substances having antibacterial properties may be mixed and supported on these inorganic substances.

As an inorganic substance carrying an antibacterial substance, a commercially available antibacterial agent may be used, and examples thereof include "Apatizer-A" manufactured by Sangi Co., Ltd. Nissei Chemical Co., Ltd. “Daikira”, Shinto Kogyo Co., Ltd. “Antibacterial Ceramics”, Matsushita Electric Industrial Co., Ltd. “Amenitop”, Toa Gosei Co., Ltd. “Novaron”, Catalytic Chemicals ( "Atomie ball" manufactured by Kanebo Kasei Co., Ltd., "Bactekira" manufactured by Kanebo Kasei Co., Ltd., "Zeomic" manufactured by Shinagawa Fuel Co., Ltd., and the like. 1-10 wt% may be filled.

Further, in order to enhance the electrochemical control of aquatic organisms, the conductive composition may be filled with a substance (electron mediator) which promotes electron transfer between the aquatic organisms and the electrode. Examples of electronic mediators include ferrocene,
Ferrocene monocarboxylic acid, ferrocene dicarboxylic acid or ferrocene such as [(trimethylamine) methyl] ferrocene or a derivative thereof, H ₄ Fe (CN) ₆ , K ₄ Fe
(CN) ₆ or Na ₄ Fe (CN) ₆ and other ferrocyanes, and other compounds such as 2,6-dichlorophenolindol, phenazine methosulfate,
Benzoquinone, phthalocyanine, brilliant cresylbu-, calocyanine, resorcin, thionine, N, N-
Dimethyl-disulfonated thionine, new methylene blue-, tobusimble-O, safranine-O,
2,6-dichlorophenol indophenol, benzyl viologen, alizarin brilliant blue, phenocyanidinone, phenazine ethosulfate and the like can be mentioned.

The conductive composition has been described in detail above.
Next, a method for forming the conductive resin layer will be described. The conductive resin layer is formed by spraying the conductive composition directly onto the substrate, brush coating, or coating by a roll coater method, followed by heating and drying if necessary, and the conductive composition in advance. Examples include a method in which an object is formed into a sheet and fixed on a base material via an adhesive. In this case, when the substrate is a non-conductor, electroless plating method or ion plating, sputtering,
If a metal layer is formed on the surface of the base material by a vacuum vapor deposition method or a metal layer is formed on the surface of the conductive resin sheet adhered to the base material by the same method, the potential of the surface of the conductive resin becomes uniform. preferable.

Next, an antifouling method using the conductive resin layer will be described. In this method, a conductive resin layer is used as a working electrode, a counter electrode made of a material having conductivity is installed to the working electrode, and a DC power source (rectifier) is used to apply a potential between the working electrode and the counter electrode. It may be applied, or the potential may be controlled by using a reference electrode. The applied potential to the working electrode is 0 to 5 Vvs. SCE, 0 for negative potential
-5 Vvs. It may be SCE, and the potential may be converted in the same range even when the positive potential and the negative potential are alternately applied.

In the present invention, the conductive resin layer is added to the conductive resin layer in water containing aquatic organisms at 0 to 5 Vvs. When a positive potential of SCE is applied, aquatic organisms attached to the surface of the resin layer are sterilized,
Further, since the aquatic organisms attached to the local non-conductive portion are sterilized by the action of the antibacterial agent, the formation of slime layers and the formation of biological layers can be prevented, and the attachment of large organisms can be prevented.

Further, 0 to -5 Vvs. When a negative potential of SCE is applied, aquatic organisms approaching the conductive resin layer cannot be attached due to electric repulsion, and even if they are attached, they are sterilized by the action of the antibacterial agent. The formation of a microbial layer can be prevented, and adhesion of large organisms can be prevented.

Further, when the positive potential and the negative potential are alternately applied, the aquatic organisms attached to the conductive resin layer are sterilized by the positive potential, and further, the sterilized aquatic organisms are removed by applying the negative potential. Since the aquatic organisms that have been separated and attached to the local non-conductive portion are sterilized by the action of the antibacterial agent, the formation of slime layers and biological layers can be prevented, and the attachment of large organisms can be prevented.

[0019]

The present invention prevents the adhesion of microorganisms by sterilizing or desorbing the microorganisms by periodically applying a positive potential or a negative potential or a positive potential and a negative potential alternately to the conductive resin layer. Since the antibacterial agent is contained in the conductive resin layer for the purpose, the electrically conductive portion sterilizes or desorbs the attached aquatic organisms by the potential application, and further adheres to the local non-conductive portion. Since the aquatic organism is sterilized by the antibacterial agent, the antifouling effect is maintained for a long period of time.

[0020]

The present invention will be described below in detail with reference to examples. In the following examples, the device shown in FIG. 1 was used. That is, the conductive resin layer electrode 3 formed on the polyester substrate 2 is arranged in the test tank 1, and the conductive resin layer electrode 3 is connected to the potentiostat 4. The potentiostat 4 is connected to a reference electrode 5 and a counter electrode 6 arranged in the test tank 1, respectively. The potentiostat 4 is also connected to the function generator 7. 500 in test tank 1
Containing ml of sterile seawater, and a stirring device 8 at the bottom.
And a stirring bar 9 is arranged. The reference electrode 5 was a saturated sweet kohle electrode (SCE), and the counter electrode 6 was a platinum plate.

<Example 1><Preparation of conductive resin layer> A tar-modified urethane resin (manufactured by Yoshida Refinery Co., Ltd.) as a binder resin was dissolved in xylene to adjust the resin solid content to 40% by weight. did. 30% by weight of graphite having a particle size of 5 μm (manufactured by Nippon Graphite Co., Ltd.) with respect to the resin solid content, 20% by weight of 0.1 μm palladium (manufactured by Tokuriki Kagaku Kenkyusho), and an antibacterial agent (Matsushita) Denki Sangyo Co., Ltd. (Amenitop) was used to disperse and fill 1.0% of the resin solid content with a ball mill to obtain a conductive composition. After mixing the obtained conductive composition and a dedicated curing agent in a weight ratio of 2: 1 and forming a conductive resin layer by a spray method on a polyester plate having a size of 30 mm × 60 mm and a thickness of 1.0 mm, After drying at 120 ° C. for 60 minutes, the conductive resin layer has a thickness of 50 μm and a specific resistance value of 0.041 Ω-c.
m conductive resin electrode was obtained. The obtained conductive resin electrode was designated as A.

Example 2 <Preparation of Conductive Resin Layer> A styrene elastomer resin (manufactured by Mitsubishi Chemical Co., Ltd.) as a binder resin was dissolved in xylene to adjust the resin solid content to 25% by weight. Nylon beads coated with palladium and having a particle size of 5 μm (nylon beads: SP-500 manufactured by Toray Industries, Inc.) were added to 40% by weight of the resin solid content and carbon black of 0.016 μm (Mitsubishi Kasei). 10% by weight of # 3600 manufactured by Co., Ltd., 0.5% by weight of antibacterial agent (Daikira manufactured by Dainichiseika Kogyo Co., Ltd.) with respect to the resin solid content, and 3% by weight of ferrocene as an electronic mediator. Then, the conductive composition was obtained by dispersing and filling with three rolls. Nylon beads coated with palladium and having a particle diameter of 5 μm were produced by the following method. Nylon beads were dispersed in 10% hydrochloric acid for etching, filtered, washed with water, and adsorbed with palladium colloid by a commonly known sensitizer and activator. Then, the nylon beads were dispersed in an electroless palladium plating solution (manufactured by Ishihara Sangyo Co., Ltd.) to obtain 50
Palladium-coated nylon beads were obtained by treatment at 50 ° C. for 50 minutes. The obtained conductive composition is 30 mm × 60
Pour into a mold having a depth of 0.2 mm and a depth of 0.2 mm, and heat at 60 ° C. for 10 hours to give a thickness of 0.1 mm and a specific resistance value of 0.
A 74 Ω-cm conductive resin sheet was obtained. The obtained conductive resin sheet was fixed to the polyester sheet used in Example 1 with an epoxy adhesive. The obtained conductive resin electrode was designated as B.

The durability of the conductive resin electrodes obtained in the examples was evaluated by water resistance and deterioration by application of a potential. The water resistance was immersed in ion-exchanged water at 90 ° C for 30 minutes, and the change in the surface condition of the conductive resin was visually observed, and the adhesion was determined according to JIS K 54.
It evaluated based on 00. The results are shown by the number of 100 grids that did not peel. The specific resistance value was measured with a 4-terminal resistance measuring device (manufactured by KEITHLEY). For the deterioration of the conductive resin layer due to the application of the electric potential, the device shown in FIG.
A conductive resin electrode is installed in sterilized seawater, and + 2Vvs. S
30 minutes at CE / -2V vs. A pulse potential for 30 minutes was continuously applied by SCE for 30 days, changes in the surface state were visually observed, and changes in weight and specific resistance were evaluated. The results are shown in Tables 1 (water resistance) and 2 (deterioration due to application of potential).

[0024]

[Table 1]

[0025]

[Table 2]

<Example 3><Sterilizationexperiment> Vibrio alginolyticus (ATC)
C 17749) and marine broth (Marine b
2216 (DIFCO Laborator)
a) was aerobically cultured at 25 ° C. for 10 hours. The cells after culturing were collected by centrifugation, washed with sterilized seawater and then suspended in sterilized seawater, and the number of cells was counted by a hematite meter to determine the cell concentration of 1 × 10 ⁸ cells / ml. 200 ml of suspension was prepared. Next, the polyester sheet having the conductive resin layer formed thereon is immersed in this suspension for 90 minutes at room temperature to allow the bacterial cells to adhere to the surface of the conductive resin, and then immersed in 500 ml of sterilized seawater contained in the test tank 1. Then, a sterilization experiment was performed while stirring the sterilized seawater at a stirring speed of 200 rpm. Potential application conditions are (1) no potential application, (2) + 1.0V
vs. SCE 12 hours, (3) +0.6 Vvs. SC
E for 12 hours, (4) + 2.0V vs. SCE 12 hours, (5) + 1.0 Vvs. 30 minutes by SCE / -0.6
Vvs. SCE 60 minutes pulse potential for 12 hours,
(6) -0.6 Vvs. SCE was done for 6 hours in 12 hours. Then, the surface of the conductive resin was pipetted for 3 minutes in a fresh 10 ml of sterilized seawater using a micropipettor to release the adhered bacteria into the seawater. This seawater was diluted to an appropriate concentration and mixed with marine broth containing 0.7% agar. Then, the cells were cultured at room temperature for 24 hours, and the number of colonies that appeared was determined to determine the number of viable cells adhering to the surface of the conductive resin. The result is that no potential was applied to the conductive resin electrode containing no antibacterial agent. Is shown as a relative value. The results are shown in Tables 3 and 4.

[0027]

[Table 3]

[0028]

[Table 4]

Comparative Example 1 A conductive resin containing no antibacterial agent was formed under the same conditions as in Example 1. The sterilization experiment was performed under the same conditions as in Example 2. The obtained conductive resin electrode is C
And The results are shown in Table 5.

[0030]

[Table 5]

[0031]

INDUSTRIAL APPLICABILITY As shown by the results of Examples and Comparative Examples, the present invention sterilizes or removes marine-adherent bacteria attached to the surface of a conductive resin by applying a potential to the conductive resin containing an antibacterial agent. Moreover, since the aquatic organisms attached to the local non-conductive part of the conductive resin surface are sterilized by the action of the antibacterial agent, the formation of slime layer and microbial layer by the aquatic organisms can be prevented. Furthermore, since large organisms can be prevented from adhering, it is possible to prevent the underwater structure from being dyed for a long period of time.

[Brief description of drawings]

FIG. 1 shows an antifouling effect confirmation test device used in Examples and Comparative Examples.

[Explanation of symbols]

 1 Test Layer 2 Substrate 3 Conductive Resin Layer Electrode 4 Potentiostat 5 Reference Electrode 6 Counter Electrode 7 Function Generator 8 Stirrer 9 Stirrer

Claims (6)

[Claims] 1. A conductive composition for forming a conductive resin layer for preventing adhesion of aquatic organisms, which is composed of at least a binder resin, a conductive filler and an antibacterial substance. A conductive composition for preventing biofouling. 2. The conductive composition for preventing the attachment of aqueous organisms according to claim 1, wherein the substance having an antibacterial property is an inorganic substance or an organic substance. 3. The electrically conductive composition for preventing adherence to aquatic organisms according to claim 1, wherein the substance having antibacterial properties is a simple metal, a metal compound or an organic substance, and the substance having antibacterial properties is carried on an inorganic substance. 4. A conductive resin layer formed on at least a contact surface with water contains at least a binder resin, a conductive filler and an antibacterial substance, and the conductive resin layer has a positive potential or a negative potential. Alternatively, an antifouling method using a conductive composition for preventing adhesion of aquatic organisms, in which a positive potential and a negative potential are alternately applied. 5. The antifouling method using the conductive composition for preventing the attachment of aqueous organisms according to claim 4, wherein the substance having antibacterial properties is an inorganic substance or an organic substance. 6. The conductive composition for preventing adherence to aquatic organisms according to claim 4, wherein the antibacterial substance is a simple metal, a metal compound or an organic substance, and the antibacterial substance is carried on an inorganic substance. Antifouling method.