Underwater cable and method for protecting underwater cable

Abstract

To provide an underwater antifouling pipe, which has excellent antifouling property even under conditions of a high biofouling load in water and is also excellent in damage resistance, an underwater cable, and a method for protecting a cable for underwater by the underwater antifouling pipe.SOLUTION: There are provided an underwater antifouling pipe, including a base material layer containing silicone as a main material and an antifouling layer containing a cured silicone body (A) and a slip agent (B) on the base material layer, with the antifouling layer as an outermost layer, an underwater cable having a cable for underwater in the underwater antifouling pipe, and a method for protecting the cable for underwater by the underwater antifouling pipe.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an underwater antifouling pipe, a manufacturing method thereof, an underwater cable, and a method for protecting an underwater cable. [Background technology]

[0002] Articles used in water, such as oceans and rivers, can suffer from various problems due to the attachment of aquatic organisms. For example, cables used for power transmission and data transfer, and hoses and pipes used for transporting liquids can suffer problems such as damage, weight increase, and reduced flexibility due to the attachment of aquatic organisms.

[0003] In response to these problems, studies have been conducted on exterior coatings and paintings for underwater articles that prevent the attachment of living organisms. For example, US Pat. No. 5,399,633 discloses a seismic streamer casing made of flexible tubing coated with a two-part layer of heat-curable silicone elastomer to prevent biofouling. Furthermore, Patent Document 2 discloses a submarine hose used for transporting crude oil or refined oil from a tanker moored to a single-point mooring buoy, the hose surface being covered with a cover for preventing adhesion of marine organisms to the hose surface for the purpose of preventing adhesion of marine organisms to the hose surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2008-506928 [Patent Document 2] JP 2001-21093 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, new underwater or above-water facilities and equipment, such as floating power plants, underwater unmanned exploration vehicles, underwater drones, and seabed stations, have been developed one after another, and as a result, cables with various sizes, strengths, and flexibility are required. On the other hand, the use of the casings and covers of Patent Documents 1 and 2 can impart a certain degree of antifouling properties against aquatic organisms, but these are still insufficient in terms of adaptability to the various applications described above and antifouling properties in various environments, particularly environments with high biofouling loads, and are also insufficient in terms of damage to cables caused by ocean currents, movement of equipment, contact with floating objects, etc. Therefore, the present invention aims to provide an underwater anti-fouling pipe, an underwater cable, and a method for protecting an underwater cable using the underwater anti-fouling pipe, which have excellent anti-fouling properties even under conditions of high biological adhesion load in water and also have excellent damage resistance. [Means for solving the problem]

[0006] In view of the above-mentioned problems, the present inventors conducted intensive research and discovered that the above-mentioned problems could be solved by an underwater anti-fouling pipe having a base layer made of silicone and an anti-fouling layer thereon containing a cured silicone and a slipping agent, and thus completed the present invention. The gist of the present invention is as follows. The present invention relates to the following [1] to

[13] . [1] An underwater antifouling pipe having a substrate layer mainly made of silicone, and an antifouling layer on the substrate layer containing a cured silicone (A) and a slipping agent (B), the antifouling layer being the outermost layer. [2] The underwater antifouling pipe described in [1], wherein the slipping agent (B) is one or more selected from oils and polymers having hydrophilic groups. [3] The underwater antifouling pipe according to [1] or [2], wherein the content of the slipping agent (B) in the antifouling layer is 1 to 30 mass %. [4] An underwater antifouling pipe described in any one of [1] to [3], wherein the slipping agent (B) is one or more selected from silicone oil, paraffin oil, oils and fats, acrylic polymers having hydrophilic groups, and polyalkylene glycols. [5] The underwater antifouling pipe described in [4], wherein the silicone oil is one or more selected from phenyl-modified silicones and polyether-modified silicones. [6] The underwater antifouling pipe described in any one of [1] to [5], wherein the antifouling layer has a thickness of 50 μm to 3 mm. [7] The underwater antifouling pipe according to any one of [1] to [6], wherein the silicone constituting the base layer is silicone rubber. [8] The underwater antifouling pipe described in any one of [1] to [7], wherein the antifouling layer is in direct contact with the base material layer. [9] The underwater antifouling pipe according to any one of [1] to [8], which contains a color pigment (C).

[10] The underwater antifouling pipe described in [9], wherein the coloring pigment (C) is present in the antifouling layer.

[11] An underwater cable having an underwater cable in an underwater antifouling tube described in any one of [1] to

[10] .

[12] A method for protecting an underwater cable by covering a surface of the underwater cable with an underwater antifouling tube described in any one of [1] to

[10] .

[13] A method for producing an underwater antifouling pipe, comprising the steps of applying an antifouling coating composition containing a curable silicone (a) and a slipping agent (B) to a substrate layer mainly made of silicone, and curing the curable silicone (a) to obtain an antifouling layer. Effect of the Invention

[0007] According to the present invention, it is possible to provide an underwater anti-fouling pipe, an underwater cable, and a method for protecting an underwater cable using the underwater anti-fouling pipe, which have excellent anti-fouling properties and excellent damage resistance even under conditions of high biological adhesion load underwater, particularly in the sea. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The underwater antifouling pipe, its manufacturing method, underwater cable, and underwater cable protection method of the present invention will be described in detail below.

[0009] [Underwater antifouling pipe] The underwater antifouling pipe of the present invention has a substrate layer mainly made of silicone, and an antifouling layer containing a cured silicone (A) and a slipping agent (B) on the substrate layer, the antifouling layer being the outermost layer.

[0010] <Base material layer> The silicone-based substrate layer constituting the underwater antifouling pipe of the present invention is mainly made of silicone. The content of silicone in the substrate layer is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more. The substrate layer is a tubular substrate that surrounds the underwater cable, etc. The substrate layer is mainly made of silicone, and it is sufficient that silicone is present in the above-mentioned ratio at least on the surface that contacts the antifouling layer, and other layers or reinforcing glass cloth, etc. may be present. Further, the substrate layer may have an additional layer therein. For example, the substrate layer may be provided on a tubular flexible resin, and the underwater antifouling pipe of the present invention further has an antifouling layer on the substrate layer. Examples of the silicone constituting the base layer include silicone resins and silicone rubbers, with silicone rubber being preferred. These silicones may be either addition reaction curing type or condensation curing type, with the addition reaction curing type being preferred from the standpoint of ease of production and strength of the base layer. By using silicone rubber for the base layer, the underwater antifouling pipe of the present invention can be made flexible, making it easier to apply to moving facilities and providing excellent damage resistance.

[0011] The inner diameter and thickness of the base layer are not particularly limited, but from the viewpoint of improving antifouling properties and manufacturing workability, the inner diameter is preferably 1 to 1,000 mm, more preferably 5 to 100 mm, and the thickness of the base layer is preferably 0.3 mm to 200 mm, more preferably 1 to 10 mm. The tensile strength of the base layer measured by a test method in accordance with JIS K 6251 is preferably 3 MPa or more, more preferably 5 MPa. The elongation at break of the base layer measured by a test method in accordance with JIS K 6251 is preferably 150% or more, more preferably 250% or more. The hardness of the substrate layer measured with a type A durometer in accordance with JIS K 6253-3 is preferably 30 or more, and more preferably 50 or more. The base layer is preferably a silicone tube or a silicone hose. Examples of commercially available silicone tubes and silicone hoses suitable for use as the base layer include silicone tubes, silicone braided hose S, and silicone delivery suction hose manufactured by Togawa Rubber Co., Ltd.

[0012] The substrate layer preferably has a light-shielding property, and the hiding rate of the substrate layer is preferably 50% or more. The substrate layer having a light-shielding property can suppress the growth of aquatic plants such as algae. The substrate layer may contain a coloring agent. Examples of the coloring agent include coloring pigments and dyes, and coloring pigments are preferred. Among them, the coloring pigments shown in the section (Coloring Pigment (C)) described later are more preferred. The substrate layer may contain silica (D) which will be described later.

[0013] <Anti-stain layer> The underwater antifouling pipe of the present invention has an antifouling layer containing a silicone cured product (A) and a slipping agent (B).

[0014] (Silicone cured body (A)) The stain-resistant layer contains a silicone cured product (A). It is believed that the inclusion of the silicone cured product (A) in the antifouling layer provides antifouling properties for a long period of time. Furthermore, because the coloring pigment can be retained on the surface of the base layer, it is believed that the growth of aquatic plants such as algae can be suppressed even inside the antifouling pipe or in cut areas where there is no antifouling layer. The silicone cured product (A) is preferably obtained by curing the curable silicone (a) described below. In this case, the structure of the silicone cured product (A) is a structure in which the raw material curable silicone (a) has been crosslinked.

[0015] Furthermore, when the antifouling layer contains a silane coupling agent (f) or an organosilicon crosslinking agent (g) described below, these may react with the curable silicone (a) and become part of the cured silicone (A).

[0016] The silicone cured product (A) has a main chain and crosslinking sites. The main chain has a polydiorganosiloxane structure, and preferably has a polydimethylsiloxane structure. The crosslinking sites will vary depending on the reactive groups of the curable silicone (a) raw materials and the reactive groups of the silane coupling agent (f) and organosilicon crosslinking agent (g), but examples include those in which a silicon atom links three or four main chains via three or four siloxane bonds, and those in which a silicon atom links to other silicon atoms via a hydrocarbon group to link main chains together, with those in which a silicon atom links three or four main chains via three or four siloxane bonds being preferred. From the viewpoint of imparting flexibility to the antifouling layer, the molecular weight between crosslinking points of the silicone cured product (A) is preferably 500 or more, more preferably 5,000 or more, even more preferably 10,000 or more, even more preferably 15,000 or more, even more preferably 20,000 or more, and is preferably 1,000,000 or less, more preferably 100,000 or less, even more preferably 50,000 or less, even more preferably 40,000 or less.

[0017] From the viewpoint of imparting long-lasting antifouling properties, the content of the silicone cured product (A) in the antifouling layer is preferably 40 mass % or more, more preferably 50 mass % or more, and even more preferably 60 mass % or more, and is preferably 95 mass % or less, more preferably 90 mass % or less. In the manufacturing method described below, the content of silicone cured product (A) in the obtained antifouling layer can be calculated by subtracting the components that are released and volatilized during curing from the total amount of the curable silicone (a), silane coupling agent (f) and organosilicon crosslinking agent (g) in the solids of the antifouling coating composition. Here, the "solid content of the antifouling coating composition" refers to the components excluding the organic solvent (i) described below and the volatile components contained as solvents in each component, and can be regarded as an antifouling layer. The "solid content of the antifouling coating composition" may be calculated by measuring the solid content (heating residue) obtained by drying the coating composition in a hot air dryer at 125°C for 1 hour. The "content of each component in the antifouling layer" can be calculated from the content of each component minus the organic solvent (i) described below, volatile components contained as a solvent in each component, and components that are eliminated and volatilized after the curing reaction.

[0018] (Slip agent (B)) The underwater antifouling pipe of the present invention contains a slipping agent (B) in the antifouling layer. The slipping agent (B) imparts slipperiness to the antifouling layer, thereby improving the inhibition of adhesion of aquatic organisms (antifouling properties). By making the surface of the underwater antifouling pipe slippery underwater, it is possible to reduce damage when it comes into contact with substances and improve workability during installation and retrieval. The slipping agent (B) is preferably one having fluidity at 25°C, and more preferably in a liquid state. It is considered that the slipping agent having fluidity has high mobility in the antifouling layer, and can enhance the effect of providing slip to the surface. In addition, the viscosity of the antifouling coating composition described later can be reduced, and the coating property can be improved. The slipping agent (B) is preferably at least one selected from oils and polymers having a hydrophilic group.

[0019] Examples of the oils include silicone oil, paraffin oil, and oils and fats, and among these, silicone oil is preferable. The paraffin oil includes liquid paraffin. The oils and fats are esters of fatty acids and glycerin, and examples of the oils and fats include animal oils and fats, vegetable oils and fats, etc.

[0020] Examples of the polymer having a hydrophilic group include an acrylic polymer having a hydrophilic group and a polyalkylene glycol, and an acrylic polymer having a hydrophilic group is preferable. Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, copolymers of ethylene glycol and propylene glycol, and alkyl ethers thereof.

[0021] That is, the slipping agent (B) is preferably one or more selected from silicone oil, paraffin oil, oils and fats, acrylic polymers having hydrophilic groups, and polyalkylene glycols, more preferably one or more selected from silicone oil and acrylic polymers having hydrophilic groups, and even more preferably silicone oil. Also, from the viewpoints of the antifouling properties, damage resistance, and manufacturing workability of the underwater antifouling pipe, it is preferable to include an acrylic polymer having a hydrophilic group, and more preferably to include both silicone oil and an acrylic polymer having a hydrophilic group. The silicone oil and the acrylic polymer having a hydrophilic group, which are suitable slipping agents (B), will be described in detail below.

[0022] [Silicone oil (B1)] Examples of the silicone oil (B1) used in the underwater antifouling pipe of the present invention include dimethyl silicone (polydimethylsiloxane, unmodified silicone) and modified silicone. Modified silicone is a dimethyl silicone in which some of the methyl groups have been replaced with organic groups other than methyl groups, and does not substantially contain reactive groups such as the curable silicone (a) described below. Silicone oil has low interfacial tension and its properties do not change easily even in environments such as low temperatures, so it easily migrates to the surface of the anti-fouling layer, efficiently improving the resistance to adhesion of aquatic organisms (anti-fouling properties) and damage resistance.

[0023] The viscosity of the silicone oil (B1) at 25°C, from the viewpoints of imparting slipperiness to aquatic organisms, improving antifouling properties, and improving the coatability of the antifouling coating composition, is preferably 10 mPa·s or more, more preferably 20 mPa·s or more, even more preferably 40 mPa·s or more, still more preferably 60 mPa·s or more, even more preferably 80 mPa·s or more, and is preferably 10,000 mPa·s or less, more preferably 5,000 mPa·s or less, and even more preferably 4,000 mPa·s or less. In this specification, the viscosity of the silicone oil (B1) at 25° C. refers to the viscosity measured with a B-type rotational viscometer.

[0024] Examples of modified silicones include phenyl-modified silicone, polyether-modified silicone, long-chain alkyl-modified silicone, higher fatty acid ester-modified silicone, fluoroalkyl-modified silicone, carbinol-modified silicone, carboxy-modified silicone, amino-modified silicone, epoxy-modified silicone, methacryl-modified silicone, mercapto-modified silicone, and phenol-modified silicone. Of these modified silicones, from the viewpoints of improving the antifouling properties and damage resistance of the underwater antifouling pipe, imparting appropriate thixotropy to the antifouling coating composition described below, and improving its coatability, the silicone oil (B1) is preferably one or more selected from phenyl-modified silicones and polyether-modified silicones, more preferably polyether-modified silicones, and even more preferably a combination of phenyl-modified silicones and polyether-modified silicones.

[0025] The structure of the modified silicone may be a side chain modified type, a both end modified type, a one end modified type, a block type, or a side chain and both end modified type.

[0026] The commercially available dimethyl silicone is "KF-96-1,000cs" (manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity (25°C): 1,000 mm 2 / sec) etc.

[0027] From the viewpoints of antifouling properties and facilitating the formation of an antifouling layer, the phenyl modification rate of the phenyl-modified silicone is preferably 3 to 50%, more preferably 3 to 20%, and even more preferably 4 to 10%. The phenyl modification rate is the number of phenyl groups relative to the total number of phenyl groups and methyl groups bonded to silicon, expressed as a percentage. The kinetic viscosity of the phenyl-modified silicone at 25°C is preferably 10 to 5000 mm from the viewpoint of the antifouling properties of the antifouling layer and the coating workability of the antifouling coating composition. 2 / sec is preferred, 100 to 3000 mm 2 / sec is more preferable, 500-2000mm 2 / sec is more preferred. A commercially available phenyl-modified silicone product is "KF-50-1,000cs" (manufactured by Shin-Etsu Chemical Co., Ltd., phenyl modification rate = 5%, kinematic viscosity (25 °C): 1,000 mm 2 / sec) etc.

[0028] When the anti-stain layer contains a phenyl-modified silicone, the content in the anti-stain layer is preferably 0.1 mass % or more, more preferably 1 mass % or more, even more preferably 3 mass % or more, and even more preferably 5 mass % or more, from the viewpoint of improving the anti-stain properties, formation efficiency, and damage resistance of the anti-stain layer, and is preferably 50 mass % or less, more preferably 40 mass % or less, even more preferably 30 mass % or less, and even more preferably 20 mass % or less.

[0029] The structure of the polyether-modified silicone may be a side-chain-modified type, a both-terminal-modified type, a block type, or a side-chain- and both-terminal-modified type, with the side-chain-modified type and the both-terminal-modified type being preferred. Examples of the polyether (polyalkylene glycol) constituting the polyether group (polyalkylene glycol group) of the polyether-modified silicone include polyethylene glycol, polypropylene glycol, and a copolymer of ethylene glycol and propylene glycol, with polyethylene glycol being preferred. From the viewpoint of antifouling properties and facilitating the formation of an antifouling layer, the proportion of the polyether partial structure in the structure of the polyether-modified silicone is preferably 10 to 50 mass %, more preferably 15 to 40 mass %. When the anti-fouling layer contains a polyether-modified silicone, the content in the anti-fouling layer is preferably 0.1 mass % or more, more preferably 0.5 mass % or more, and even more preferably 1 mass % or more, from the viewpoint of improving the anti-fouling properties of the anti-fouling layer and making it easier to form the anti-fouling layer, and is preferably 20 mass % or less, more preferably 10 mass % or less, and even more preferably 7 mass % or less.

[0030] When the anti-fouling layer contains a polyether-modified silicone containing an ethyleneoxy (-OC2H4-) structural unit and / or an acrylic polymer (B2) having a hydrophilic group having an ethyleneoxy (-OC2H4-) structure described below, from the viewpoint of imparting good anti-fouling properties and damage resistance to the anti-fouling layer, the total mass of the ethyleneoxy (-OC2H4-) partial structures per 100 parts by mass of the dimethylsiloxane partial structure (-(CH3)2Si-O-) of the silicone is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass. The kinetic viscosity of the polyether modified silicone at 25°C is preferably 10 to 5000 mm from the viewpoints of antifouling properties and coating workability of the antifouling coating composition. 2 / sec is preferred, 50 to 2000 mm 2 / sec is more preferable, 100-500mm 2 / sec is more preferred. Commercially available polyether-modified silicone products include "X-22-4272" (Shin-Etsu Chemical Co., Ltd., double-ended type, kinematic viscosity (25°C): 270 mm 2 / sec), "KF-6020" (Shin-Etsu Chemical Co., Ltd., side chain type, kinetic viscosity (25°C): 180 mm 2 / sec), "FZ-2203" (manufactured by Dow Corning Toray Co., Ltd., side chain type), and "FZ-2160" (manufactured by Dow Corning Toray Co., Ltd., block type).

[0031] The content of silicone oil (B1) in the antifouling layer is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, even more preferably 6% by mass or more, and is preferably 50% by mass or less, more preferably 35% by mass or less, even more preferably 25% by mass or less, and even more preferably 15% by mass or less, from the viewpoint of improving the antifouling properties of the antifouling layer and making it easier to form the antifouling layer.

[0032] [Acrylic polymer having hydrophilic group (B2)] The acrylic polymer (B2) having a hydrophilic group used in the underwater antifouling pipe of the present invention preferably contains a structural unit derived from a monomer having a hydrophilic group, more preferably contains a structural unit derived from a monomer having a hydrophilic group and a structural unit derived from a hydrophobic monomer, and even more preferably consists of a structural unit derived from a monomer having a hydrophilic group and a structural unit derived from a hydrophobic monomer. The content of the structural unit derived from the monomer having a hydrophilic group in the acrylic polymer having a hydrophilic group (B2) is preferably 1 to 100 mass%, more preferably 3 to 80 mass%, even more preferably 5 to 70 mass%, and even more preferably 10 to 60 mass%. It is believed that the acrylic polymer has hydrophilic groups, and when the underwater antifouling pipe of the present invention is installed underwater, the hydrophilic portion of the acrylic polymer dissolves or swells and gradually migrates to the surface of the antifouling layer, thereby efficiently preventing the attachment of aquatic organisms. In addition, because it has an acrylic structure, it is believed that the antifouling properties can be maintained for a long period of time by undergoing gradual hydrolysis and changing its affinity for water. As the hydrophilic group of the monomer having a hydrophilic group, from the viewpoint of the antifouling property and damage resistance of the underwater antifouling pipe, an ether group or a hydroxyl group is preferable, and an ether group is more preferable.

[0033] In addition, the content of structural units derived from hydrophobic monomers in the acrylic polymer (B2) having a hydrophilic group is preferably 99% by mass or less, more preferably 97% by mass or less, even more preferably 95% by mass or less, even more preferably 90% by mass or less, and is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more. It is believed that the inclusion of a hydrophobic monomer provides high affinity with other components of the antifouling layer, such as the silicone crosslinked product, and enables a uniform slip effect to be exhibited on the surface of the antifouling layer.

[0034] As the monomer having a hydrophilic group, from the viewpoint of the anti-fouling properties and damage resistance of the underwater anti-fouling pipe, a monomer having a polyalkylene glycol group, a monomer having a hydroxyl group, and a monomer having an alkoxyalkyl group are preferred, and a monomer having a polyalkylene glycol group is more preferred. Specifically, from the viewpoint of improving the antifouling properties, one or more selected from polyalkylene glycol (meth)acrylate, hydroxyalkyl (meth)acrylate, alkoxyalkyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 4-(meth)acryloylmorpholine, and vinylpyrrolidone are preferred, one or more selected from polyalkylene glycol (meth)acrylate and hydroxyalkyl (meth)acrylate are more preferred, and polyalkylene glycol (meth)acrylate is even more preferred. In addition, "(meth)acrylate" means "acrylate or methacrylate".

[0035] Examples of the polyalkylene glycol (meth)acrylate include those in which one end of the polyalkylene glycol is bonded to (meth)acrylic acid directly via an ester bond or a linking group, and the remaining end is a hydroxyl group or an alkoxy group, and those which are alkoxy groups are preferred. Among these, polyalkylene glycols in which one end is directly ester-bonded to (meth)acrylic acid are preferred, and those in which the remaining end is an alkoxy group are more preferred. The terminal (meth)acrylic acid is preferably acrylic acid or methacrylic acid, and more preferably acrylic acid. Examples of the terminal alkoxy group include a methoxy group, a phenoxy group, and an octoxy group, with a methoxy group and a phenoxy group being preferred, and a methoxy group being more preferred.

[0036] The polyalkylene glycol constituting the polyalkylene glycol (meth)acrylate is preferably polyethylene glycol, polypropylene glycol, or a copolymer of ethylene glycol and propylene glycol, and more preferably polyethylene glycol. The average number of alkylene glycol units constituting the polyalkylene glycol in the polyalkylene glycol (meth)acrylate is preferably 2-25, more preferably 3-15, and even more preferably 5-12.

[0037] Specific examples of polyalkylene glycol (meth)acrylates include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, poly(ethylene glycol-propylene glycol) mono(meth)acrylate, poly(ethylene glycol-butylene glycol) mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, allyloxypoly(ethylene glycol-propylene glycol) mono(meth)acrylate, phenoxypolyethylene glycol-polypropylene glycol methacrylate, octoxypoly(ethylene glycol-propylene glycol) mono(meth)acrylate, dodecyloxypolyethylene glycol mono(meth)acrylate, octadecyloxypolyethylene glycol mono(meth)acrylate, nonylphenoxypolypropylene glycol acrylate, and the like, with methoxypolyethylene glycol mono(meth)acrylate being preferred.

[0038] Commercially available polyalkylene glycol (meth)acrylates include NK Ester AM-90G (methoxypolyethylene glycol #400 acrylate), NK Ester AM-130G (methoxypolyethylene glycol #550 acrylate), NK Ester M-90G (methoxypolyethylene glycol #400 methacrylate), and NK Ester 130G (methoxypolyethylene glycol #550 acrylate), all manufactured by Shin-Nakamura Chemical Co., Ltd. M-230G (methoxypolyethylene glycol #1000 methacrylate); Light Acrylate MTG-A (methoxy-triethylene glycol acrylate), Light Acrylate EC-A (ethoxy-diethylene glycol acrylate), Light Acrylate EHDG-AT (2-ethylhexyl-diethylene glycol acrylate), Light Ester 041MA (methoxypolyethylene glycol methacrylate) manufactured by Kyoeisha Chemical Co., Ltd.; Blemmer ANP-300 (nonylphenoxy polypropylene glycol acrylate), Blemmer AP-400 (polypropylene glycol monoacrylate), Blemmer 70PEP-350B (polyethylene glycol polypropylene glycol monomethacrylate), Blemmer 55PET-800 (polyethylene glycol tetramethylene glycol monomethacrylate), Blemmer 50POEP-800B (octoxypolyethylene glycol polypropylene glycol methacrylate) manufactured by NOF Corporation; and Viscoat #MTG (methoxypolyethylene glycol acrylate) manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0039] Examples of the hydroxyalkyl (meth)acrylate include hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate. Commercially available hydroxyalkyl (meth)acrylate products include Light Ester HOA(N) (2-hydroxyethyl acrylate), Light Ester HO-250(N) (2-hydroxyethyl methacrylate), and Light Ester HOP(N) (2-hydroxypropyl methacrylate), all manufactured by Kyoeisha Chemical Co., Ltd.

[0040] Examples of the alkoxyalkyl (meth)acrylate include methoxyethyl (meth)acrylate.

[0041] As the tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl acrylate and tetrahydrofurfuryl methacrylate are preferred, and tetrahydrofurfuryl acrylate is more preferred. As the 4-(meth)acryloylmorpholine, 4-acryloylmorpholine and 4-methacryloylmorpholine are preferable, and 4-acryloylmorpholine is more preferable. Examples of vinylpyrrolidone include 1-vinyl-2-pyrrolidone (N-vinyl-2-pyrrolidone), 3-acetyl-1-vinylpyrrolidin-2-one, and 3-benzoyl-1-vinylpyrrolidin-2-one, with 1-vinyl-2-pyrrolidone being preferred.

[0042] Examples of the hydrophobic monomer include alkyl(meth)acrylates having a branched, linear or cyclic alkyl group having 1 to 30 carbon atoms, aryl(meth)acrylates having an aromatic group having 6 to 10 carbon atoms, and (meth)acrylic group-containing silicones. Of these, alkyl(meth)acrylates and (meth)acrylic group-containing silicones are preferred, and alkyl(meth)acrylates are more preferred.

[0043] The alkyl group of the alkyl (meth)acrylate preferably has 1 to 30 carbon atoms, more preferably 4 to 18 carbon atoms, further preferably 4 to 8 carbon atoms, and even further preferably 4 to 6 carbon atoms. The alkyl group may be branched, straight-chained or cyclic, preferably branched or straight-chained, and more preferably branched.

[0044] Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, and isooctyl (meth)acrylate. acrylate, 2-ethylhexyl (meth)acrylate, 3,5,5-trimethylhexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, phenyl (meth)acrylate, and benzyl (meth)acrylate, and among these, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred.

[0045] The aromatic group of the aryl(meth)acrylate preferably has 6 to 10 carbon atoms, and more preferably has 6 to 7 carbon atoms. Specific examples of the aryl(meth)acrylate include phenyl(meth)acrylate and benzyl(meth)acrylate.

[0046] Examples of the (meth)acrylic group-containing silicone include methacrylic group-containing silicone and acrylic group-containing silicone, with methacrylic group-containing silicone being preferred. The (meth)acrylic group-containing silicone is preferably one in which a (meth)acrylic group is bonded to one end of the silicone main chain via a linking group, or one in which a (meth)acrylic group is bonded directly to one end of the silicone main chain, and more preferably one in which a (meth)acrylic group is bonded to one end of the silicone main chain via a linking group. The linking group is preferably a trimethylene group. The silicone main chain is preferably made of linear or branched dimethyl silicone (polydimethylsiloxane), and more preferably made of linear dimethyl silicone. Furthermore, it is more preferable that an alkyl group having 1 to 6 carbon atoms is present at the end opposite to the (meth)acrylic group, and it is more preferable that a butyl group is present. Commercially available (meth)acrylic group-containing silicones include Silaplane TM-0701T (tris(trimethylsiloxy)silylpropyl methacrylate), Silaplane FM-0711 (methacrylic group-containing dimethylpolysiloxane, number average molecular weight 1,000), and Silaplane FM-0721 (methacrylic group-containing dimethylpolysiloxane, number average molecular weight 5,000), all manufactured by JNC Corporation. By including a (meth)acrylic group-containing silicone, the antifouling properties of the antifouling coating film that is formed can be improved.

[0047] The weight average molecular weight (Mw) of the acrylic polymer (B2) having a hydrophilic group is, from the viewpoint of antifouling property and the viscosity of the antifouling coating composition, preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, even more preferably 7,000 or more, and is preferably 150,000 or less, more preferably 100,000 or less, even more preferably 50,000 or less, and even more preferably 30,000 or less. It is preferable that the weight average molecular weight (Mw) of the hydrophilic group-containing acrylic polymer (B2) is within the above range, since good antifouling properties and damage resistance can be imparted to the antifouling layer.

[0048] When the antifouling layer of the underwater antifouling pipe of the present invention contains an acrylic polymer (B2) having a hydrophilic group, the content of the acrylic polymer (B2) having a hydrophilic group in the antifouling layer is preferably 0.2% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, from the viewpoint of antifouling property and damage resistance, and is preferably 50% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0049] (Coloring Pigment (C)) The antifouling layer in the underwater antifouling pipe of the present invention preferably contains a color pigment (C). The inclusion of a color pigment in the antifouling layer can enhance damage resistance. Furthermore, it is believed that the inclusion of a color pigment in the antifouling layer can block sunlight and other light from reaching the interior and gaps of the underwater antifouling pipe where the antifouling layer does not exist, thereby suppressing the growth of aquatic plants such as algae. The color pigment (C) is not particularly limited, and examples thereof include inorganic pigments such as iron oxide, titanium oxide, carbon black, zinc oxide, aluminum silicate, alumina white, and barium sulfate; and organic pigments such as naphthol red and phthalocyanine blue. From the viewpoints of the production operability and coating operability of the antifouling coating composition, storage stability, and the antifouling properties and damage resistance of the antifouling layer, inorganic pigments are preferred, and among these, one or more pigments selected from iron oxide, titanium oxide, carbon black, zinc oxide, aluminum silicate, alumina white, and barium sulfate are preferred, one or more pigments selected from iron oxide, titanium oxide, and carbon black are preferred, and one or more pigments selected from iron oxide and titanium oxide are more preferred. Examples of iron oxide include red iron oxide, yellow iron oxide, and black iron oxide. As the titanium oxide, any of the rutile type, anatase type and brookite type can be used, and from the viewpoints of the stability and availability of the antifouling layer and the antifouling coating composition, it is preferable to use the rutile type. Examples of organic pigments include naphthol red and phthalocyanine blue. The content of the color pigment (C) in the antifouling layer is preferably 0.01 to 20 mass%, more preferably 1 to 10 mass%, and even more preferably 4 to 10 mass%, from the viewpoints of excellent antifouling properties and damage resistance of the antifouling layer, as well as excellent production workability, coating workability, and storage stability of the antifouling coating composition.

[0050] (Silica (D)) The antifouling layer in the underwater antifouling pipe of the present invention preferably contains silica (D) from the viewpoint of improving the physical properties such as hardness, flexibility, and strength of the antifouling layer. Silica (D) not only improves the physical properties of the antifouling layer, but also improves the fluidity and thixotropy of the antifouling coating composition which is the raw material thereof.

[0051] As the silica (D), dry process silica and wet process silica are preferred, and dry process silica is more preferred. The dry process silica is not particularly limited, but the adsorbed water content is preferably 1.5% by mass or less, the bulk density is preferably 50 to 100 g / L, the primary particle size is preferably 8 to 20 μm, and the specific surface area (BET surface area) is preferably 10 m 2 / g or more is preferred. The wet-process silica is not particularly limited, but the adsorbed water content is preferably 4 to 8 mass %, the bulk density is preferably 200 to 300 g / L, the primary particle size is preferably 10 to 30 μm, and the specific surface area is preferably 10 m 2 / g or more is preferred.

[0052] The silica (D) is not particularly limited, but from the viewpoint of the coatability of the antifouling coating composition, hydrophilic silica and hydrophobic silica are preferred, and hydrophobic silica is more preferred. It is also preferred to use hydrophilic silica and hydrophobic silica in combination. The hydrophilic silica is untreated silica (surface-untreated silica), and examples thereof include dry process silica (fumed silica, anhydrous silica) and wet process silica (hydrated silica), with dry process silica being preferred and fumed silica being more preferred. Commercially available hydrophilic silica products include "AEROSIL 200" manufactured by Nippon Aerosil Co., Ltd.

[0053] The hydrophobic silica is hydrophobically treated silica (silica whose surface has been hydrophobically treated), and examples thereof include aqueous wet-process silica and hydrophobic fumed silica. Examples of hydrophobic fumed silica include silica obtained by surface-treating dry-process silica with one or more organosilicon compounds selected from methyltrichlorosilane, dimethyldichlorosilane, hexamethyldisilazane, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane, and silica surface-treated with hexamethyldisilazane is preferred. The hydrophobic fumed silica is not particularly limited, but the water content is preferably 0.3 mass% or less, more preferably 0.05 to 0.2 mass%, the primary particle size is preferably 5 to 50 nm, the bulk density is preferably 50 to 100 g / L, and the specific surface area is preferably 10 m 2 It is preferable that the molecular weight is 1 / g or more.

[0054] Commercially available hydrophobic silica products include "AEROSIL R974" and "AEROSIL RX200" manufactured by Nippon Aerosil Co., Ltd.

[0055] From the viewpoint of improving the strength and hardness of the antifouling layer, the content of silica (D) in the antifouling layer is preferably 0.1 mass% or more, more preferably 1 mass% or more, and is preferably 20 mass% or less, more preferably 10 mass% or less.

[0056] The content of silica (D) per 100 parts by mass of the silicone cured product (A) in the anti-fouling layer is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, from the viewpoint of improving the strength and hardness of the anti-fouling layer, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less.

[0057] (Biological repellents (E)) The antifouling layer preferably contains a biological repellent (E) for the purpose of enhancing antifouling properties.

[0058] The biological repellent (E) is eluted from the antifouling layer in water and has the effect of inhibiting aquatic organisms from attaching to the surface of the antifouling layer, thereby improving the antifouling properties. The biological repellent (E) is preferably one having a repellent effect against aquatic organisms and a certain dissolution rate in water, and is preferably one or more selected from copper pyrithione, zinc pyrithione, 4-bromo-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile (also known as tralopyril), and 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (also known as DCOIT). From the viewpoint of dissolution from the antifouling layer and repellent effect against a wide range of biological species, one or more selected from copper pyrithione and zinc pyrithione are more preferred, and from the viewpoint of dissolution, copper pyrithione is even more preferred. The biological repellent (E) may be used alone or in combination of two or more. The content of the biological repellent (E) in the antifouling layer is preferably 0.1 mass% or more, more preferably 1 mass% or more, and even more preferably 5 mass% or more, from the viewpoints of the strength and antifouling properties of the antifouling layer, and the coatability of the antifouling coating composition, and is preferably 30 mass% or less, more preferably 20 mass% or less, and even more preferably 10 mass% or less.

[0059] <Configuration of underwater antifouling pipe> As described above, the underwater antifouling pipe of the present invention has a substrate layer mainly made of silicone, and an antifouling layer on the substrate layer containing a cured silicone material (A) and a slipping agent (B), the antifouling layer being the outermost layer.

[0060] The underwater antifouling pipe of the present invention preferably contains a color pigment (C). The color pigment (C) is preferably present in the substrate layer, the antifouling layer, or both the substrate layer and the antifouling layer, more preferably in the antifouling layer, or both the substrate layer and the antifouling layer, and even more preferably in the antifouling layer.

[0061] The cross-sectional shape of the underwater antifouling pipe of the present invention may be a circle, an ellipse, a polygon such as a rectangle, etc., and is preferably a circle or an ellipse, more preferably a circle. In addition, the shapes of the outer circumference and the inner circumference of the pipe may be different, but are preferably the same. It is preferable to select the optimum thickness, overall thickness and inner diameter of the underwater antifouling pipe depending on the thickness, strength, installation location, application, etc. of the underwater cables to be introduced inside.

[0062] The underwater antifouling pipe of the present invention may have one or more slits in the longitudinal direction of the pipe, and from the viewpoint of ease of installation, it is preferable that the slits are present. For example, an underwater antifouling pipe obtained by winding one or more of the substrates having a C-shaped, L-shaped, or I-shaped cross section around an underwater cable or the like and then tying the substrate has a slit in the longitudinal direction. Therefore, when a pipe having a slit is used, the underwater antifouling pipe of the present invention is preferably one in which the slit is closed by coating the slit with an antifouling paint composition or by joining the slit, after the underwater antifouling pipe having a slit is wound around an underwater cable or the like. On the other hand, from the viewpoint of exerting high antifouling properties, it is preferable that the opening area of ​​the slit is small, and it is more preferable that the pipe does not have a slit.

[0063] The outermost layer of the underwater anti-fouling pipe of the present invention is an anti-fouling layer, and the outermost layer refers to the layer that has a surface that faces the underwater cable, etc. (inner side) and a surface that comes into contact with the external water on the opposite side (outer side) when the underwater anti-fouling pipe of the present invention is laid underwater. The thickness of the antifouling layer is preferably 10 μm to 3 mm, more preferably 30 μm to 3 mm, even more preferably 50 μm to 3 mm, still more preferably 50 μm to 1 mm, even more preferably 50 to 500 μm, even more preferably 75 to 500 μm, and even more preferably 100 to 500 μm.

[0064] The antifouling layer preferably has a light-shielding property, and the concealing ratio of the antifouling layer is preferably 50% or more, more preferably 70% or more, even more preferably 90% or more, and even more preferably 95% or more. The light-shielding property of the antifouling layer can block light such as sunlight from reaching the inside or the cut parts, and can suppress the growth of aquatic plants such as algae.

[0065] The underwater antifouling pipe of the present invention preferably has softness and flexibility, which prevents damage due to water currents such as ocean currents and enables use in facilities that move underwater or on the water.

[0066] [Protection methods for underwater cables and underwater cables] The underwater cable of the present invention has an underwater cable in the underwater antifouling pipe. Underwater cables are used to connect surface facilities, undersea facilities, underwater floating facilities, underwater mobile facilities, ships, etc., or to connect these to facilities on land, for the purpose of transmitting electricity or communicating communications. Underwater cables are made of electrical conductors, optical fibers, etc. covered with an insulator or the like. It is preferable for underwater cables to have a metallic water-resistant layer, especially when they are immersed in water for long periods of time. The underwater cable of the present invention has an underwater cable in an underwater anti-fouling tube, but it is preferable that the underwater cable is in the internal cavity of the underwater anti-fouling tube, and it is preferable that all parts of the underwater cable that are present underwater are covered by the underwater anti-fouling tube.

[0067] The method for protecting an underwater cable of the present invention involves covering the surface of the underwater cable with an underwater antifouling tube. Methods for covering the surface of an underwater cable with an underwater anti-fouling tube include inserting the underwater cable into the internal cavity of the underwater anti-fouling tube, winding an underwater anti-fouling tube having a slit in the longitudinal direction around the underwater cable and tying it together, and covering the underwater cable with a number of short underwater anti-fouling tubes and then joining the underwater anti-fouling tubes. From the viewpoint of ease of installation, the method of winding an underwater anti-fouling tube having a slit in the longitudinal direction around the underwater cable and tying them together is preferred. On the other hand, from the viewpoint of exerting high anti-fouling properties, the method of inserting the underwater cable into the internal cavity of the underwater anti-fouling tube is preferred. By covering the underwater cable with the underwater antifouling tube, the underwater cable can be protected from contamination and damage caused by aquatic organisms, and can also be protected from damage caused by water currents and drifting debris.

[0068] [Manufacturing method for underwater antifouling pipes] The method for producing an underwater antifouling pipe of the present invention includes a step of applying an antifouling coating composition containing a curable silicone (a) and a slipping agent (B) to a substrate layer mainly made of silicone, and a step of curing the curable silicone (a) to obtain an antifouling layer. If one or more slits are present in the longitudinal direction of the pipe, it is preferable to provide a step before or after the above two steps of winding one or more of the substrates around an underwater cable or the like and then tying them together to obtain an underwater anti-fouling pipe, and it is more preferable to apply an anti-fouling paint composition to the slits or join the slits after winding one or more of the substrates around an underwater cable or the like to seal the slits.

[0069] <Antifouling paint composition> The antifouling coating composition used in the production method of the present invention contains a curable silicone (a) and a slip agent (B). As the slipping agent (B), the slipping agent (B) described above in the <<anti-stain layer>> is preferably used. Furthermore, the antifouling coating composition used in the present production method preferably contains, in addition to the curable silicone (a) and the slipping agent (B), a coloring pigment (C), silica (D) and a biological repellent (E), and the coloring pigment (C), silica (D) and biological repellent (E) described above in <Antifouling Layer> are preferably used, respectively.

[0070] (Curable silicone (a)) The curable silicone (a) has a main chain and reactive sites. The main chain has a polyorganosiloxane structure, and examples of the polyorganosiloxane structure include a polydimethylsiloxane structure and a polymethylphenylsiloxane structure. Of these, a polydimethylsiloxane structure is preferable, and an alkylene group, a polyoxyalkylene group, or the like may be present in a block form. Furthermore, for example, an alkylene group or a polyoxyalkylene group may be present as a linking site between the main chain and the reactive site. The reactive site is an addition reactive group or a condensation reactive group, and is preferably a condensation reactive group from the viewpoint of being less affected by curing inhibitors in the curing reaction and being able to obtain a stable reaction rate. The reactive sites of the curable silicone (a) react with each other or with the organosilicon crosslinking agent (g) contained in the antifouling coating composition to form a crosslinked structure, which becomes a silicone cured body and forms an antifouling layer. They may also react with the silane coupling agent (f) to form part of the silicone cured body.

[0071] Examples of the condensation reactive group include a silanol group, an oximesilyl group, an acyloxysilyl group, an alkoxysilyl group, an alkenyloxysilyl group, an aminosilyl group, and an amidosilyl group. Of these, a silanol group, an oximesilyl group, an acyloxysilyl group, an alkoxysilyl group, and an alkenyloxysilyl group are preferred, a silanol group, an oximesilyl group, an alkoxysilyl group, and an alkenyloxysilyl group are more preferred, a silanol group, an oximesilyl group, an alkoxysilyl group, and an alkenyloxysilyl group are even more preferred, and a silanol group and an oximesilyl group are even more preferred. The oxime group is preferably an oxime group having 1 to 10 carbon atoms, more preferably a dimethylketoxime group, a methylethylketoxime group, a diethylketoxime group, or a methylisopropylketoxime group, and still more preferably a methylethylketoxime group. The alkoxy group is preferably an alkoxy group having 1 to 6 carbon atoms, more preferably a methoxy group, an ethoxy group, a propoxy group, or a butoxy group, more preferably a methoxy group or an ethoxy group, and even more preferably a methoxy group. Two or more oxime groups or alkoxy groups may be bonded to one silicon atom, and it is preferable that two or more oxime groups or alkoxy groups are bonded to one silicon atom.

[0072] The location of the reactive site may be a direct bond to a silicon atom of the main chain, in a side chain, at both ends of the main chain, or at one end of the main chain, with both ends of the main chain being preferred.

[0073] Specific examples of the curable silicone (a) include silanol group-containing silicones, oximesilyl group-containing silicones, alkoxy group-containing silicones, and enol silyl ether group-containing silicones. Of these, silanol group-containing silicones, oximesilyl group-containing silicones, and alkoxy group-containing silicones are preferred, and silanol group-containing silicones and oximesilyl group-containing silicones are more preferred.

[0074] From the viewpoint of improving coating workability, curability of the coating composition, and strength of the coating film formed, the weight average molecular weight (Mw) of the curable silicone (a) is preferably 500 or more, more preferably 5,000 or more, even more preferably 10,000 or more, still more preferably 15,000 or more, still more preferably 20,000 or more, and is preferably 1,000,000 or less, more preferably 100,000 or less, still more preferably 50,000 or less, and still more preferably 40,000 or less. In the present invention, the "weight average molecular weight (Mw)" is measured using GPC (gel permeation chromatography) and calculated by converting it into standard polystyrene of known molecular weight.

[0075] The viscosity of the curable silicone (a) at 25°C is preferably 20 mPa·s or more, more preferably 100 mPa·s or more, more preferably 500 mPa·s or more, and even more preferably 1000 mPa·s or more, from the viewpoint of improving the production workability of the coating composition, the coating workability and curability of the coating composition, and the strength and flexibility of the coating film formed, and is preferably 100,000 mPa·s or less, more preferably 10,000 mPa·s or less, and even more preferably 5,000 mPa·s or less. The viscosity of the curable silicone (a) at 25° C. is measured using a B-type rotational viscometer (for example, model BM, manufactured by Tokyo Keiki Co., Ltd.).

[0076] From the viewpoint of improving the strength of the antifouling layer to be formed, the content of the curable silicone (a) in the antifouling coating composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less.

[0077] Commercially available curable silicone (a) products include "DMS-S35" manufactured by GELEST and "KE-445" manufactured by Shin-Etsu Chemical Co., Ltd.

[0078] (Slip agent (B)) As the slip agent (B) used in the antifouling coating composition, the slip agent (B) described above in the <Antifouling Layer> is suitably used, and specific suitable compounds are also as described above.

[0079] The content of the silicone oil (B1) in the antifouling coating composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, from the viewpoint of improving the coating workability of the antifouling coating composition and the antifouling properties and damage resistance of the antifouling layer, and is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0080] The content of the acrylic polymer (B2) having a hydrophilic group in the antifouling coating composition is, from the viewpoint of improving the antifouling properties and facilitating the formation of an antifouling layer, preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less.

[0081] (Coloring Pigment (C)) The antifouling coating composition preferably contains a color pigment (C). The color pigment (C) used in the antifouling coating composition is preferably the color pigment (C) described in the <Antifouling Layer> above, and specific preferred compounds are also as described above. The content of the color pigment (C) in the antifouling coating composition is preferably from 0.01 to 20% by mass, more preferably from 1 to 10% by mass, and even more preferably from 3 to 8% by mass.

[0082] (Silica (D)) The antifouling coating composition preferably contains silica (D). The silica (D) used in the antifouling coating composition is preferably the silica (D) described above in the <antifouling layer>, and specific preferred compounds are also as described above.

[0083] The content of silica (D) in the antifouling coating composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, and is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less.

[0084] The content of silica (D) per 100 parts by mass of curable silicone (a) in the antifouling coating composition is, from the viewpoint of improving the thixotropy of the antifouling coating composition, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 12 parts by mass or less.

[0085] (Biological repellents (E)) The antifouling coating composition preferably contains a biological repellent (E). As the biological repellent (E) used in the antifouling coating composition, the biological repellent (E) described above in the <Antifouling Layer> is suitably used, and specific suitable compounds are also as described above. The content of the biological repellent (E) in the antifouling coating composition is preferably 0.05% by mass or more, more preferably 1% by mass or more, and is preferably 50% by mass or less, more preferably 30% by mass or less.

[0086] (Other Ingredients) The antifouling coating composition used in the manufacturing method of the present invention may contain other components in addition to the curable silicone (a), slip agent (B), and the above-mentioned color pigment (C), silica (D), and biological repellent (E). Examples of other components include a silane coupling agent (f), an organosilicon crosslinking agent (g), a curing catalyst (h), an organic solvent (i), a pigment other than the color pigment (C) and silica (D), a dehydrating agent, an anti-sagging agent / anti-settling agent, an enzyme, a flame retardant, and a thermal conductivity improver. It is preferable to contain a silane coupling agent (f), an organosilicon crosslinking agent (g), a curing catalyst (h), and an organic solvent (i).

[0087] [Silane coupling agent (f)] The antifouling coating composition preferably contains a silane coupling agent (f) for the purpose of improving the adhesion and curing properties of the antifouling layer. The silane coupling agent (f) is an organic alkoxysilane having at least one alkoxy group and at least one organic reactive group on the silicon atom. The alkoxy group is preferably a methoxy group or an ethoxy group, and more preferably a methoxy group. One to three alkoxy groups are bonded to the silicon atom, preferably two or three alkoxy groups are bonded, and more preferably three alkoxy groups are bonded to the silicon atom. Examples of the organic reactive group include an amino group, a mercapto group, an epoxy group, an isocyanate group, a ureido group, a vinyl group, an acryl group, a methacryl group, and a styryl group. Of these, an amino group, a mercapto group, an epoxy group, an isocyanate group, and a ureido group are preferred, an amino group, a mercapto group, and an epoxy group are more preferred, and an amino group is even more preferred. Specific examples of the organic reactive group containing an amino group include preferably a 2-(aminoethyl)-3-aminopropyl group and a 3-aminopropyl group, and more preferably a 2-(aminoethyl)-3-aminopropyl group.

[0088] Examples of the silane coupling agent (f) include 3-(2-aminoethylamino)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-(2-aminoethylamino)ethylamino)propyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-isocyanatepropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. Of these, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane are preferred, and 3-(2-aminoethylamino)propyltrimethoxysilane is more preferred. The silane coupling agent (f) may be a condensate of the above-mentioned compound. The silane coupling agent (f) may be used alone or in combination of two or more kinds.

[0089] The content of the silane coupling agent (f) in the antifouling coating composition is preferably from 0.01 to 5 mass %, more preferably from 0.03 to 1 mass %, and even more preferably from 0.05 to 0.5 mass %. The content of the silane coupling agent (f) in the antifouling coating composition relative to 100 parts by mass of the curable silicone (a) is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 1 part by mass, and even more preferably 0.05 to 0.5 parts by mass.

[0090] [Organosilicon Crosslinking Agent (g)] The antifouling coating composition preferably contains an organosilicon crosslinking agent (g) in order to improve the curing rate and the strength of the antifouling layer. The organosilicon crosslinking agent (g) is an organosilanes having three or four hydrolyzable groups on the silicon atom, and when it has three hydrolyzable groups, it also has one hydrocarbon group, and its partial condensates are also included. The number of hydrolyzable groups per silicon atom is three or four, and preferably four. The hydrolyzable group is preferably an alkoxy group or an oxime group, and more preferably an alkoxy group. The alkoxy group is preferably a methoxy group or an ethoxy group. The hydrocarbon group is preferably a hydrocarbon group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, or a propyl group, and even more preferably a methyl group or an ethyl group. Examples of the organosilicon crosslinking agent (g) include tetraethyl orthosilicate, partial decondensation products of tetraethyl orthosilicate, alkyltrialkoxysilanes, and oximesilanes, with tetraethyl orthosilicate and partial hydrolysis condensation products of tetraethyl orthosilicate being preferred.

[0091] Commercially available products of tetraethyl orthosilicate include "Ethyl Silicate 28" manufactured by Colcoat Co., Ltd. and "Ethyl Orthosilicate" manufactured by Tama Chemical Industries Co., Ltd. Commercially available partial hydrolysis condensates of tetraethyl orthosilicate include "Silicate 40" manufactured by Tama Chemical Industries Co., Ltd. and "WACKER SILICATE TES 40 WN" manufactured by Wacker Asahi Kasei Silicones Co., Ltd. Commercially available alkyltrialkoxysilanes include "KBM-13" manufactured by Shin-Etsu Chemical Co., Ltd. Commercially available oxime silane products include "MTO (MOS)" (methyl tris (methyl ethyl ketoxime) silane) and "VTO (VOS)" (vinyl tris (methyl ethyl ketoxime) silane) manufactured by Toray Industries, Inc. The organosilicon crosslinking agent (g) may be used alone or in combination of two or more kinds.

[0092] The content of the organosilicon crosslinking agent (g) in the antifouling coating composition is preferably from 0.5 to 10 mass %, more preferably from 1 to 5 mass %, and even more preferably from 2 to 4 mass %. The content of the organosilicon crosslinking agent (g) in the antifouling coating composition is preferably 1.5 to 30 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 3 to 10 parts by mass, per 100 parts by mass of the curable silicone (a).

[0093] [Curing catalyst (h)] The antifouling coating composition preferably contains a curing catalyst (h) in order to improve the curing rate and the film strength of the antifouling layer. The curing catalyst (h) may be an organometallic compound, preferably a tin compound, a titanium compound, or an alkali metal salt of a lower fatty acid, more preferably a tin compound or a titanium compound, and even more preferably a tin compound.

[0094] Examples of the tin compound include dibutyltin diacetate, dibutyltin acetoacetonate, dibutyltin dilaurate, dibutyltin diolate, dibutyltin oxide, dibutyltin dimethoxide, dibutyltin dipentanoate, dibutyltin dioctoate, dibutyltin dineodecanoate, dioctyltin dineodecanoate, bis(dibutyltin laurate) oxide, dibutylbis(triethoxysiloxy)tin, bis(dibutyltin acetate) oxide, dibutyltin bis(ethyl malate), dioctyltin bis(ethyl malate), tin naphthenate, and tin oleate. Dibutyltin diacetate, dibutyltin acetoacetonate, dibutyltin dilaurate, dibutyltin diolate, dibutyltin oxide, dibutyltin dimethoxide, dibutyltin dipentanoate, dibutyltin dioctoate, and dibutyltin dineodecanoate are preferred, and dibutyltin dilaurate is more preferred. Commercially available tin compounds include "NEOSTANN U-100" manufactured by Nitto Kasei Co., Ltd. and "Gleck TL" manufactured by DIC Corporation.

[0095] Examples of the titanium compound include tetraisopropoxytitanium, tetra-N-butoxytitanium, tetrakis(2-ethylhexoxy)titanium, dipropoxybis(acetylacetonato)titanium, and titanium isopropoxyoctyl glycol. Examples of organometallic compounds other than tin compounds and titanium compounds include zinc naphthenate, zinc stearate, zinc 2-ethyloctoate, iron 2-ethylhexoate, cobalt 2-ethylhexoate, manganese 2-ethylhexoate, cobalt naphthenate, and alkoxyaluminum compounds. Examples of the alkali metal salts of lower fatty acids include potassium acetate, sodium acetate, and lithium oxalate. The curing catalyst (h) may be used alone or in combination of two or more kinds.

[0096] The content of the curing catalyst (h) in the antifouling coating composition is preferably from 0.001 to 10 mass %, more preferably from 0.01 to 3 mass %, and even more preferably from 0.1 to 1 mass %, from the viewpoint of improving the curing rate. The content of the curing catalyst (h) in the antifouling coating composition relative to 100 parts by mass of the curable silicone (a) is preferably 0.003 to 30 parts by mass, more preferably 0.03 to 5 parts by mass, and even more preferably 0.3 to 3 parts by mass.

[0097] [Organic solvent (i)] The antifouling coating composition according to the present invention may contain an organic solvent (i) in order to keep the viscosity of the coating composition low and improve coating workability. Examples of the organic solvent (i) include aromatic hydrocarbon-based organic solvents, aliphatic hydrocarbon-based organic solvents, alicyclic hydrocarbon-based organic solvents, ketone-based organic solvents, and ester-based organic solvents. Of these, aromatic hydrocarbon-based organic solvents and ketone-based organic solvents are preferred, and aromatic hydrocarbon-based organic solvents are more preferred. Examples of the aromatic hydrocarbon organic solvent include toluene, xylene, and mesitylene, with xylene being preferred. Aliphatic hydrocarbon organic solvents include pentane, hexane, heptane, and octane. Examples of the alicyclic hydrocarbon organic solvent include cyclohexane, methylcyclohexane, and ethylcyclohexane. Examples of the ketone organic solvent include acetylacetone, acetone, methyl ethyl ketone, methyl isobutyl ketone, and dimethyl carbonate, with acetylacetone being preferred. An example of the ester-based organic solvent is propylene glycol monomethyl ether acetate. The organic solvent (i) may be used alone or in combination of two or more kinds. The content of the organic solvent (i) in the coating composition is preferably 1 mass % or more, more preferably 10 mass % or more, and even more preferably 20 mass % or more from the viewpoint of improving coating workability, and is preferably 70 mass % or less, more preferably 50 mass % or less, and even more preferably 40 mass % or less from the viewpoint of suppressing sagging during coating and reducing the burden of solvent recovery.

[0098] [Other optional components] Examples of pigments other than the color pigment (C) and silica (D) include mica, calcium carbonate, barium carbonate, potassium feldspar, kaolin, and short glass fibers. These inorganic fillers may be used alone or in combination of two or more. Examples of the dehydrating agent include zeolite, porous alumina, and orthoesters such as alkyl orthoformate, orthoboric acid, and isocyanates. Anti-sagging and anti-settling agents include organic clay waxes (such as stearate salts of Al, Ca, and Zn, lecithin salts, and alkylsulfonates), organic waxes (such as polyethylene wax, oxidized polyethylene wax, amide wax, polyamide wax, and hydrogenated castor oil wax), and mixtures of organic clay waxes and organic waxes. Examples of the enzyme include serine proteases, cysteine ​​proteases, metalloproteinases, cellulases, hemicellulases, pectinases, and glycosidases. Flame retardants include antimony oxide and paraffin oxide. Thermal conductivity improvers include boron nitride, aluminum oxide, and the like.

[0099] (Multi-liquid antifouling paint composition) The antifouling coating composition may be a one-component antifouling coating composition in which the components are one composition, or a multi-component antifouling coating composition in which the components are two or more compositions and mixed before application. From the viewpoint of preventing deterioration during storage, a multi-component antifouling coating composition is preferred, and from the viewpoint of coating workability, a one-component antifouling coating composition is more preferred. Examples of the multi-component antifouling coating composition include a two-component antifouling coating composition and a multi-component antifouling coating composition having three or more components. From the viewpoint of coating workability, a two-component antifouling coating composition is preferred, and from the viewpoint of preventing deterioration during storage, a multi-component antifouling coating composition having three or more components is preferred. In the case of a multi-component antifouling coating composition, it is preferable that the curable silicone (a), the silane coupling agent (f), the organosilicon crosslinking agent (g) and the curing catalyst (h) are contained in different liquids, and it is even more preferable that the silane coupling agent (f), the organosilicon crosslinking agent (g) and the curing catalyst (h) are contained in yet another different liquid. The color pigment (C), silica (D) and biological repellent (E) are preferably contained in the same liquid as the curable silicone (a). In addition, in the case of a multi-liquid type antifouling coating composition, the content of each component in the antifouling coating composition is the content relative to the total amount of all the components.

[0100] <Production of antifouling coating composition> The antifouling coating composition is preferably produced as follows. First, it is preferable to have a step of kneading the curable silicone (a) and the silica (D). In addition, heating may be performed during or after kneading. By kneading these in advance, the affinity between the two components is improved, and the aggregation of silica and the increase in viscosity of the coating composition can be suppressed. The heating conditions are preferably 100° C. or higher, more preferably 100 to 300° C., and even more preferably 140 to 200° C. The pressure is preferably normal pressure or reduced pressure, and the treatment time is preferably 3 to 30 hours.

[0101] The antifouling coating composition can be obtained by mixing and stirring the above-mentioned components. When the antifouling coating composition is a one-component antifouling coating composition, it is obtained by appropriately adding the essential components of the curable silicone (a) and the slipping agent (B) to the optional components of the coloring pigment (C), silica (D), the biological repellent (E), the silane coupling agent (f), the organosilicon crosslinking agent (g), the curing catalyst (h) and the organic solvent (i), and mixing and stirring them.

[0102] When the antifouling coating composition is a multi-liquid type antifouling coating composition, the curable silicone (a), the silane coupling agent (f), the organosilicon crosslinking agent (g) and the curing catalyst (h) are preferably contained in different liquids. When the antifouling coating composition is a three- or more-liquid type multi-liquid type antifouling coating composition, the silane coupling agent (f), the organosilicon crosslinking agent (g) and the curing catalyst (h) are preferably further contained in different liquids. It is also preferred that the color pigment (C), silica (D) and biological repellent (E) are contained in the same liquid as the curable silicone (a). The slipping agent (B) may be contained in either liquid, and it is preferable that the liquid containing the curable silicone (a) contains an acrylic polymer (B2) having a hydrophilic group, and the liquid containing the curing catalyst (h) contains a silicone oil (B1). In addition, the organic solvent (i) is preferably contained in both liquids. Mixing and stirring is preferably carried out at 0 to 50°C.

[0103] <Step of applying antifouling coating composition to substrate layer> This step is a step of applying the antifouling coating composition to a substrate layer mainly made of silicone. This step forms a coating film on the substrate layer. The substrate layer may be subjected to pretreatment such as cleaning, polishing, chemical etching, laser ablation, plasma treatment, etc., before coating. The method for applying the antifouling coating composition can be a known method, and examples of such methods include coating with a spray, brush, roller, film applicator, flow coater, roll coater, etc., and impregnating the substrate with the antifouling coating composition. Coating with a spray or brush is preferred, and coating with a spray is more preferred. After application, a mold may be pressed against the coating film before curing to provide an uneven structure on the surface of the antifouling layer. Examples of such uneven structures include a riblet structure that has the effect of reducing water flow friction resistance. When the multi-liquid antifouling coating composition is used, it is preferable to mix and stir all the liquids at room temperature (20 to 30° C.) immediately before application, and it is more preferable to mix and stir them using a disperser. The amount of the antifouling coating composition to be applied varies depending on the application method, application purpose, and size of the underwater antifouling pipe to be obtained, but is generally 10 to 3,000 g / m2 in terms of solid content. 2 is preferable, and 50 to 3000 g / m 2 is more preferred.

[0104] <Step of Curing the Curable Silicone (a) to Obtain an Antifouling Layer> This step is a step in which the curable silicone (a) is cured to obtain an antifouling layer. The curable silicone (a) is contained in the coating film formed in the previous step, and is cured in this step to obtain a silicone cured product. The silicone cured product obtained in this step is preferably the same as the silicone cured product (A) described above.

[0105] The temperature for curing the coating film is preferably 0 to 200° C., more preferably 10 to 150° C. When the temperature is within the above range, coating film defects caused by volatilization of the solvent or generation of gas accompanying curing are unlikely to occur, and a smooth antifouling layer can be obtained. The curing time is preferably from 1 minute to 3 days, and more preferably from 3 minutes to 2 days. The curing may be carried out in an airflow atmosphere in order to promote the removal of the solvent and by-product gases, but it is preferable to carry out the curing in a windless environment in order to prevent defects in the coating film. The thickness of the antifouling layer obtained in this step is preferably 10 μm to 3 mm, more preferably 30 μm to 3 mm, even more preferably 50 μm to 3 mm, still more preferably 50 μm to 1 mm, and even more preferably 50 to 500 μm. EXAMPLES

[0106] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0107] [Components of antifouling paint composition] The components used in the coating composition are shown in Table 1. The viscosity and kinetic viscosity in Table 1 are all values ​​at 25°C.

[0108] [Table 1]

[0109] <Acrylic polymer having hydrophilic group (B2)> Synthesis Example 1 (Synthesis of Polymer (B21)) The reaction was carried out under normal pressure and nitrogen atmosphere. 42.86 parts by mass of methyl amyl ketone was charged into a reaction vessel equipped with a stirrer, reflux condenser, thermometer, nitrogen inlet tube, and dropping funnel, and heated with stirring until the methyl amyl ketone reached 100°C. While maintaining the temperature of the reaction mixture at 100±5°C, a mixture consisting of 40.0 parts by mass of NK Ester AM-90G (methoxypolyethylene glycol acrylate, average number of polyethylene glycol units 9, manufactured by Shin-Nakamura Chemical Co., Ltd.), 60.0 parts by mass of isobutyl acrylate, and 4.0 parts by mass of 2,2'-azobis(2-methylbutyronitrile) was dropped into the reaction vessel over 4 hours. After that, the mixture was stirred for 2 hours while maintaining the temperature at 100±5°C, and a solution of polymer (B21) was obtained. The solid content of the obtained solution was 70.3% by mass, the viscosity was 109 mPa·s, and the weight average molecular weight (Mw) of polymer (B21) was 9,100.

[0110] (Solid content of polymer solution) The polymer solution was dried at 108° C. and 1 atmospheric pressure for 3 hours, and the mass of the solid content obtained was divided by the mass of the polymer solution before drying to determine the solid content (mass %).

[0111] (Viscosity of polymer solution) The viscosity (mPa·s) of the polymer solution at a liquid temperature of 25°C was measured using an E-type viscometer (TV-25, Toki Sangyo Co., Ltd.).

[0112] (Average molecular weight of polymer) The weight average molecular weight (Mw) of the polymer was measured by gel permeation chromatography (GPC) under the following conditions. (GPC conditions) Equipment: "HLC-8220GPC" (Tosoh Corporation) Columns: "TSKgel SuperH2000" and "TSKgel SuperH4000" (manufactured by Tosoh Corporation, 6 mm (inner diameter), 15 cm (length)) were connected. Eluent: tetrahydrofuran (THF) Flow rate: 0.500mL / min Detector: RI Column thermostat temperature: 40℃ Standard material: polystyrene Sample preparation: THF was added to the polymer solution, and the solution was filtered through a membrane filter to obtain a sample for GPC measurement.

[0113] [Production of antifouling paint composition] Production Examples 1 to 6 (Production of Antifouling Paint Compositions) <Mixture of curable silicone (a) and silica (D)> The curable silicone (a) and silica (D) shown in Table 1 were kneaded in the ratio shown in Table 2 to obtain a kneaded product.

[0114] [Table 2]

[0115] <Antifouling paint composition> Each component was blended according to the blending amounts (parts by mass) shown in Table 3, and the liquids of the base agent, curing agent, and additive were mixed and stirred to obtain a three-liquid type antifouling coating composition (Production Example 1). Also, each component was blended according to the blending amounts (parts by mass) shown in Table 3, and the liquids of the base agent and curing agent were mixed and stirred to obtain a two-liquid type antifouling coating composition (Production Example 2). The components were blended according to the blending amounts (parts by mass) shown in Table 4, and mixed and stirred to obtain one-component antifouling coating compositions (Production Examples 3 to 6).

[0116] [Table 3]

[0117] [Table 4]

[0118] <Manufacture of underwater antifouling pipes> Example 1 Immediately before application, the base material, curing agent, and additives of the three-component antifouling coating composition obtained in Preparation Example 1 were placed in a container and mixed, and the mixture was thoroughly stirred using a disperser to obtain a homogeneous mixture, thereby obtaining antifouling coating composition Y1. Next, the antifouling paint composition Y1 was applied with a brush to the outer surface of a silicone tube (made of silicone rubber, obtained from AS ONE Corporation) having an inner diameter of 7 mm and an outer diameter of 9 mm, while measuring the amount of antifouling paint composition Y1 to be applied, so that the antifouling layer had a uniform thickness of 200 μm (film thickness after drying), and then dried at 23° C. for 1 day to obtain an underwater antifouling pipe P1.

[0119] Example 2 Immediately before application, the base agent and curing agent of the two-component antifouling coating composition obtained in Preparation Example 2 were placed in a container and mixed, and the mixture was thoroughly stirred using a disperser to obtain a homogeneous mixture, thereby obtaining antifouling coating composition Y2. An underwater antifouling pipe P2 was obtained in the same manner as in Example 1, except that the antifouling coating composition Y2 was used instead of the antifouling coating composition Y1.

[0120] Example 3 The antifouling paint composition Y3 was applied to the outer surface of a silicone tube (made of silicone rubber, obtained from AS ONE Corporation) with an inner diameter of 7 mm and an outer diameter of 9 mm so that the antifouling layer had a thickness (film thickness after drying) of 50 μm, and the tube was dried at 23°C for one day to obtain an underwater antifouling tube P3.

[0121] [Examples 4 to 8 and Comparative Example 1] In Example 3, the antifouling coating composition and the thickness of the antifouling layer (film thickness after drying) were changed as shown in Table 5, but the same procedure as in Example 3 was repeated to obtain underwater antifouling pipes P4 to P8 and C1.

[0122] Comparative Example 2 In Example 3, the silicone tube was changed to a vinyl tube (made of polyvinyl chloride resin, manufactured by Yakoh Co., Ltd., product name: vinyl tube hose) with an inner diameter of 7 mm and an outer diameter of 9 mm, and an antifouling coating composition Y3 was applied so that the thickness of the antifouling layer (film thickness after drying) was 200 μm. An underwater antifouling pipe C2 was obtained in the same manner as in Example 3.

[0123] Comparative Example 3 In Example 3, a silicone tube that was not coated with the antifouling coating composition was used for evaluation as an underwater antifouling tube C3.

[0124] <Anti-stain property evaluation> The underwater antifouling pipes manufactured in the Examples and Comparative Examples were immersed in the ocean (Hiroshima Bay, Seto Inland Sea) at a depth of 1 m from the sea surface, and after 3 months, the area occupied by marine organisms was evaluated according to the following criteria. The smaller the area occupied by marine organisms, the better the antifouling properties. (Standards for stain resistance) 5: The area occupied by marine organisms is less than 10% of the entire outer surface of the underwater antifouling pipe. 4: The area occupied by marine organisms is between 10% and 30% of the entire outer surface of the underwater antifouling pipe. 3: The area occupied by marine organisms is 30% or more but less than 50% of the entire outer surface of the underwater antifouling pipe. 2: The area occupied by marine organisms is 50% or more but less than 80% of the entire outer surface of the underwater antifouling pipe. 1: The area occupied by marine organisms is 80% or more of the entire outer surface of the underwater antifouling pipe.

[0125] <Slipperiness evaluation (damage resistance evaluation)> The slipperiness of the surface of the underwater antifouling pipe was evaluated underwater. Specifically, the underwater antifouling pipes manufactured in the Examples and Comparative Examples were touched with the pads of their fingers in water at 23°C, and evaluated individually by 10 people, with Example 7 as the control. The evaluation was based on the following criteria, and the average scores are shown in Table 5. Slippery materials (those with a high slipperiness rating) have less damage to their stain-resistant layer due to friction, and therefore have excellent damage resistance. (Slipperiness evaluation criteria) 3: More slippery than Example 7 2: Equivalent to Example 7 1: Less slippery than Example 7

[0126] <Algae growth suppression performance inside underwater antifouling pipes> The underwater anti-fouling pipes manufactured in the examples and comparative examples were drilled with 1 mm diameter holes at 0.2 m intervals, immersed in the ocean (Hiroshima Bay, Seto Inland Sea) 1 m below the sea surface, and seawater was allowed to circulate inside. After 6 months, each underwater anti-fouling pipe was cut open and the growth of algae on the inner surface of the underwater anti-fouling pipe was evaluated according to the following criteria. The smaller the area occupied by algae, the more the growth of algae inside the underwater anti-fouling pipe was suppressed, and the better the algae growth suppression performance. (Evaluation criteria for algae growth inhibition performance) 5: The area occupied by algae is less than 10% of the entire outer surface of the underwater antifouling pipe. 4: The area occupied by algae is 10% or more but less than 30% of the entire outer surface of the underwater antifouling pipe. 3: The area occupied by algae is 30% or more but less than 50% of the entire outer surface of the underwater antifouling pipe. 2: The area occupied by algae is 50% or more but less than 80% of the entire outer surface of the underwater antifouling pipe. 1: The area occupied by algae is 80% or more of the entire outer surface of the underwater antifouling pipe.

[0127] [Table 5]

[0128] The results of the examples show that the underwater anti-fouling pipe of the present invention has excellent anti-fouling properties even under conditions of high biological adhesion load when used underwater, and has excellent slip properties, so it is less susceptible to loads when coming into contact with floating objects in the sea, other cables, underwater rocks, etc., and also has excellent damage resistance. Furthermore, it can be seen that the underwater anti-fouling pipe of the present invention is able to suppress the growth of algae even inside the underwater anti-fouling pipe where no anti-fouling layer is present, probably because the anti-fouling layer has light-blocking properties and remains on the surface of the base material layer for a long period of time.

Claims

1. An underwater cable having an underwater cable in an underwater antifouling pipe, The underwater anti-fouling pipe has a substrate layer mainly made of silicone, and an anti-fouling layer on the substrate layer, which contains a silicone cured product (A) obtained by reacting and curing a curable silicone (a) having a condensation reactive group and a silane coupling agent (f), which is an organic alkoxysilane having an amino group, and a slipping agent (B), the anti-fouling layer being an outermost layer having a surface in contact with external water on the opposite side to a side facing the underwater cable, the anti-fouling layer having a thickness of 75 to 500 μm, and containing a coloring pigment (C), and the substrate layer is a silicone tube or a silicone hose.

2. 2. The underwater cable according to claim 1, wherein the slipping agent (B) is at least one selected from the group consisting of oils and polymers having a hydrophilic group.

3. 3. The underwater cable according to claim 1, wherein the content of the slipping agent (B) in the antifouling layer is 1 to 30 mass %.

4. 4. The underwater cable according to claim 1, wherein the slipping agent (B) is at least one selected from the group consisting of silicone oil, paraffin oil, oils and fats, acrylic polymers having a hydrophilic group, and polyalkylene glycols.

5. 5. The underwater cable according to claim 4, wherein the silicone oil is at least one selected from the group consisting of phenyl-modified silicones and polyether-modified silicones.

6. 6. The underwater cable according to claim 1, wherein the antifouling layer has a thickness of 100 to 500 μm.

7. The underwater antifouling pipe comprises only the base layer and the antifouling layer, 7. The underwater cable according to claim 1, wherein the silicone constituting the base layer is silicone rubber.

8. The underwater cable according to any one of claims 1 to 7, wherein the antifouling layer is directly on the base material layer.

9. An underwater cable as described in any one of claims 1 to 8, wherein the antifouling layer contains a biological repellent (E) which is one or more species selected from copper pyrithione and zinc pyrithione.

10. 10. The underwater cable according to claim 1, wherein the color pigment (C) is present in the antifouling layer.

11. A method for protecting an underwater cable by covering the surface of the underwater cable with an underwater antifouling tube, comprising the steps of: The underwater anti-fouling pipe has a substrate layer mainly made of silicone, and an anti-fouling layer on the substrate layer, the anti-fouling layer containing a silicone cured product (A) obtained by reacting and curing a curable silicone (a) having a condensation reactive group and a silane coupling agent (f), which is an organic alkoxysilane having an amino group, and a slipping agent (B), the anti-fouling layer being an outermost layer having a surface in contact with external water on the opposite side to a side facing the underwater cable, the anti-fouling layer having a thickness of 75 to 500 μm, and containing a coloring pigment (C), the substrate layer being a silicone tube or a silicone hose.

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