Aquatic life adhesion preventive coating agent and ship's bottom surface modification method

Abstract

To provide an aquatic life adhesion preventive coating agent which enables formation of a film exhibiting a contamination adhesion preventive function over a long period.SOLUTION: An aquatic life adhesion preventive coating agent contains silicone resin and a disilanol compound. The silicone resin contains T unit siloxane and D unit siloxane in a molar ratio of 10:90 to 95:5. The disilanol compound has a weight average molecular weight of 100,000 to 150,000, and silanol groups at both terminals of the molecules. As for the aquatic life adhesion preventive coating agent, when an adhesion preventive film 10 is formed, the film is formed by the silicon resin, the silanol groups of each of both terminals of the molecules in the disilanol compound are coupled to the silicone resin, and a loop-shaped body 11 is formed from the surface of the adhesion preventive film toward the outside thereof by a polysiloxane main chain having inferior compatibility to the silicone resin. The loop-shaped body is elastically deformable, even though an aquatic life 3 is attached thereto, the aquatic life 3 is quickly peeled therefrom.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technical field of this specification relates to an anti-fouling coating agent for forming a coating on underwater structures such as the ship bottom of a ship to prevent the adhesion of crustaceans, shellfish, algae, etc., and a surface modification method for modifying the surface of an underwater structure with the anti-fouling coating agent.

Background Art

[0002] Conventionally, anti-fouling paints that are applied to underwater structures such as the ship bottom of a ship to prevent the adhesion of crustaceans, shellfish, algae, etc. are known. Conventional anti-fouling paints contain tin compounds (such as tributyltin oxide (TBTO)) and copper compounds (such as cuprous oxide) as anti-fouling agents, and these anti-fouling agents are gradually released to exhibit an anti-fouling function. However, these anti-fouling agents caused marine pollution. As anti-fouling paints for suppressing marine pollution, Patent Documents 1 to 3 describe anti-fouling paints containing an acrylic-based composition as an anti-fouling agent.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the anti-adhesion paints described in the conventional Patent Documents 1 to 3 exhibit an anti-fouling adhesion prevention function by the slow release of the anti-adhesion agent from the film formed by the anti-adhesion paint. For this reason, the conventional anti-adhesion paints have a problem that they cannot exhibit the anti-fouling adhesion prevention function because the anti-adhesion agent is completely released from the formed film.

[0005] The technology described in this specification solves the above problems, and an object thereof is to provide an anti-aquatic organism adhesion coating agent that forms a film exhibiting an anti-fouling adhesion prevention function over a long period of time.

Means for Solving the Problems

[0006] The anti-aquatic organism adhesion coating agent according to the embodiment of this specification contains a silicone resin and a disilanol compound. The silicone resin contains, in a molar ratio, a siloxane represented by the formula (R 1 SiO 3 / 2 ) (hereinafter referred to as "T-unit siloxane") and a siloxane represented by the formula (R 2 2SiO 2 / 2 ) (hereinafter referred to as "D-unit siloxane") in the binding structural unit, with the T-unit siloxane: the D-unit siloxane = 10:90 to 95:5. The disilanol compound is characterized in that it has a weight average molecular weight of 100,000 to 150,000, has silanol groups at both ends of the molecule, and the main chain is polydimethylsiloxane or a diphenylsiloxane-dimethylsiloxane copolymer.

[0007] According to the anti-fouling coating agent for aquatic organisms of the embodiment, when the applied anti-fouling coating agent for aquatic organisms forms a film on the surface such as the bottom of a ship to form an anti-fouling film, the silicone resin forms a film with flexibility, and in the disilanol compound, each silanol group at both ends of the molecule binds to the silicone resin, and a polysiloxane main chain with poor compatibility with the silicone resin forms a loop-shaped body outward from the surface of the anti-fouling film. The formed loop-shaped body has a large weight average molecular weight of 100,000 to 150,000 and is capable of elastic deformation. Therefore, the anti-fouling film formed from the anti-fouling coating agent for aquatic organisms can be easily peeled off even when crustaceans, shellfish, or algae adhere due to the elastic deformation of the loop-shaped body, so that the adhesion of crustaceans, shellfish, or algae can be prevented.

[0008] Here, in the anti-fouling coating agent for aquatic organisms, the silicone resin can be contained in a molar ratio of the T-unit siloxane: the D-unit siloxane = 60:40 to 90:10.

[0009] According to this, the anti-fouling film formed from the anti-fouling coating agent for aquatic organisms can have appropriate flexibility and excellent protectiveness for the surface such as the bottom of a ship.

[0010] Also, in the anti-fouling coating agent for aquatic organisms, it can be a combination with a curing catalyst.

[0011] According to this, when forming a film to form a film, the curing time can be shortened.

[0012] Here, the surface modification method of the bottom of a ship according to the embodiment is a surface modification method for modifying the surface of the bottom of a ship with an anti-fouling coating agent for aquatic organisms, a glass-based undercoat is applied to the surface of the bottom of the ship to form a glass-based film forming step for forming a glass-based film, The formed glass-based film is coated with the above anti-fouling coating agent for aquatic organisms to form an anti-fouling film, characterized by having an anti-fouling film forming step.

[0013] According to the surface modification method of the ship bottom of the embodiment, the surface of the ship bottom is protected by a glass-based film formed from a glass-based undercoat agent, and an anti-fouling coating agent for aquatic organisms is coated on the glass-based film. Therefore, the adhesion of the anti-fouling coating agent for aquatic organisms can be enhanced, and the durability of the glass-based film and the anti-fouling film can be enhanced.

[0014] Further, in the above surface modification method of the ship bottom, the glass-based undercoat agent contains 5 to 20% by mass of silicone resin, 5 to 20% by mass of alkylalkoxysilane, and 60 to 85% by mass of diluent. The silicone resin contains a siloxane represented by the formula (SiO 4 / 2 ), hereinafter referred to as "Q-unit siloxane".

[0015] According to this, the Q-unit siloxane contained in the silicone resin of the glass-based undercoat agent can enter into the fine irregularities of the ship bottom that becomes the object to be coated, and the adhesion of the glass-based undercoat agent can be enhanced. In addition, since the glass-based film formed from the glass-based undercoat agent contains alkylalkoxysilane, it has flexibility due to the alkyl group of alkylalkoxysilane and can be excellent in the surface protection of the ship bottom.

[0016] Further, in the above surface modification method of the ship bottom, the silicone resin contains a siloxane represented by the formula (R 3 SiO 3 / 2 ), hereinafter referred to as "T-unit siloxane".

[0017] According to this, the glass-based film formed from the glass-based undercoat agent has flexibility and can follow the movement such as the bending of the ship bottom. Therefore, it can be excellent in the surface protection of the ship bottom.

Advantages of the Invention

[0018] According to the anti-fouling coating agent for aquatic organisms of the embodiment, the film formed from the anti-fouling coating agent for aquatic organisms can prevent the adhesion of crustaceans, shellfish, algae, etc.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0020] Hereinafter, the embodiments of this specification will be described. In the embodiment, as shown in FIG. 1, an anti-fouling coating agent for forming an anti-fouling film 10 for modifying the surface of the bottom 1 of a ship as an underwater structure, and a glass-based undercoat agent for forming a glass-based film 12 as an undercoat of the anti-fouling coating agent for aquatic organisms will be described, and a surface modification method for modifying the surface of the bottom 1 of the ship will also be described. Of course, the embodiments of this specification are not limited to the application to the bottom 1 of a ship as an underwater structure, and can also be applied to the aquaculture facilities for fish and shellfish such as the quay walls and breakwaters of harbors, and aquaculture rafts. Note that the marine environment and seawater 2 in this specification are used for convenience, and also include river environments and fresh water, and brackish waters.

[0021] As used herein, "crustaceans" refers to the general term for arthropods of the class Crustacea, including shrimp, crabs, crayfish, barnacles, etc. Crustaceans that adhere to the ship bottom 1 include barnacles, oyster drills, etc. "Mollusks" refers to the general term for mollusks having a calcareous exoskeleton (shell), and mollusks that adhere to the ship bottom 1 include the great whelk (Buccinidae), the Chinese whelk, etc. "Algae" refers to the general term for plants growing in water, including green algae, charophytes, yellow algae, yellow-brown algae, euglenoids, brown algae, red algae, cyanobacteria, etc. When crustaceans, mollusks, or algae (hereinafter sometimes referred to as "aquatic organisms 3") adhere to the ship bottom 1 of a ship, etc., it becomes a resistance to the propulsion of the ship, and also impairs the appearance. Therefore, it is necessary to prevent the adhesion of aquatic organisms 3.

[0022] The ship bottom 1 of a ship as an underwater structure is formed of steel plates, wooden boards, FRP (Fiber Reinforced Plastics) of fiber-reinforced plastics, etc. Also, breakwaters and sea walls as underwater structures are formed of concrete molded bodies. Note that steel plates include those coated with rust preventive paint, those coated with synthetic resin, etc. The anti-aquatic organism adhesion coating agent of the embodiment can be applied regardless of these materials.

[0023] The anti-aquatic organism adhesion coating agent contains a silicone resin containing a T-unit siloxane and a D-unit siloxane, and a disilanol compound having silanol groups at both ends of the molecule.

[0024] A silicone resin is a resin (oligomer) having a siloxane bond ((-Si-O-) n ) as a skeleton, and is formed by the dehydration condensation reaction of silanol groups of siloxanes which are bonding structural units. As shown in FIG. 2, as siloxanes of the bonding structural units forming the silicone resin, there are M-unit siloxanes (monofunctional), D-unit siloxanes (bifunctional), T-unit siloxanes (trifunctional), and Q-unit siloxanes (tetrafunctional).

[0025] The T-unit siloxane is a siloxane in which the bonding structural unit is represented by the formula (R 1 SiO 3 / 2 ), and it is a trifunctional siloxane. The anti-fouling coating film 10 formed from an anti-fouling coating agent containing a silicone resin having a large amount of T-unit siloxane contains a large amount of trifunctional siloxane that is the bonding structural unit of the silicone resin, so a strong coating film (anti-fouling coating film 10) bonded three-dimensionally is formed. The anti-fouling coating film 10 containing a silicone resin having a large amount of T-unit siloxane becomes a hard and slightly less flexible film. Also, since the T-unit siloxane is trifunctional, even if two functional groups form the main chain, one functional group remains, so it easily binds to the silanol group of the disilanol compound. Note that R 1 in the formula of the bonding structural unit and R 2 described below are organic substituents, and are methyl groups and / or phenyl groups.

[0026] The D-unit siloxane is a siloxane in which the bonding structural unit is represented by the formula (R 2 2SiO 2 / 2 ), and it is a difunctional siloxane. The anti-fouling coating film 10 formed from an anti-fouling coating agent containing a silicone resin having a large amount of D-unit siloxane forms a coating film (anti-fouling coating film 10) composed of an aggregate of chain-like bodies in which difunctional siloxanes that are the bonding structural units of the silicone resin are two-dimensionally bonded. Therefore, the anti-fouling coating film 10 containing a silicone resin having a large amount of D-unit siloxane becomes a flexible film.

[0027] The silicone resin of the anti-fouling coating agent for aquatic organisms can also bond with the silanol groups of the disilanol compound by containing T-unit siloxane. In the anti-fouling film 10 formed by the anti-fouling coating agent for aquatic organisms, the polysiloxane main chain of the disilanol compound forms a loop-shaped body 11. Due to the elastic deformation of the loop-shaped body 11, even if crustaceans, shellfish, or algae adhere, they will peel off immediately. Therefore, it can prevent the adhesion of crustaceans, shellfish, or algae. Further, since the silicone resin of the anti-fouling coating agent for aquatic organisms further contains D-unit siloxane, the anti-fouling film 10 formed by the anti-fouling coating agent for aquatic organisms has flexibility and can follow the movements such as the deflection of the bottom 1 of a ship.

[0028] The molar ratio of T-unit siloxane to D-unit siloxane can be T-unit siloxane:D-unit siloxane = 10:90 to 95:5. This is because the anti-fouling film 10 formed by the anti-fouling coating agent for aquatic organisms can be excellent in anti-fouling property against aquatic organisms 3 and excellent in protectiveness. If the amount of T-unit siloxane is less than the above, the amount of the disilanol compound that can bond will decrease, and the anti-fouling property of the anti-fouling film 10 formed by the anti-fouling coating agent for aquatic organisms against aquatic organisms 3 may be inferior. Also, relatively, the amount of D-unit siloxane increases, and the anti-fouling film 10 formed by the anti-fouling coating agent for aquatic organisms becomes too flexible a layer, and the durability of the anti-fouling film 10 may be inferior. On the other hand, if the amount of T-unit siloxane is more than the above, relatively, the amount of D-unit siloxane decreases, and the flexibility of the anti-fouling film 10 formed by the anti-fouling coating agent for aquatic organisms may be inferior, and the protectiveness may be inferior. As another embodiment, T-unit siloxane:D-unit siloxane = 40:60 to 95:5 can be used, and as yet another embodiment, T-unit siloxane:D-unit siloxane = 60:40 to 90:10 can be used.

[0029] In addition, the ratio of the T-unit siloxane to the D-unit siloxane can also be represented by the R / Si ratio. In the R / Si ratio, the T-unit siloxane having one organic group per silicon atom has an R / Si ratio of 1.0. The D-unit siloxane having two organic groups per silicon atom has an R / Si ratio of 2.0. According to this, the R / Si ratio that enables the anti-fouling film 10 formed by the anti-fouling coating agent for preventing aquatic organism adhesion to be excellent in slipperiness and excellent in protectiveness can be 1.05 to 1.9. As another embodiment, the R / Si ratio can be 1.05 to 1.6, and as yet another embodiment, it can be 1.1 to 1.4.

[0030] As the silicone resin contained in the anti-fouling coating agent for preventing aquatic organism adhesion, an oligomer (copolymer oligomer) in which a T-unit siloxane and a D-unit siloxane are copolymerized can be used. In addition, as the silicone resin contained in the anti-fouling coating agent for preventing aquatic organism adhesion, an oligomer (mixed oligomer) obtained by mixing an oligomer in which a T-unit siloxane is polymerized and an oligomer in which a D-unit siloxane is polymerized can also be used. The anti-fouling coating agent containing the copolymer oligomer forms an anti-fouling film 10 having uniform flexibility. The anti-fouling coating agent containing the mixed oligomer forms an anti-fouling film 10 in which a microscopically hard film and a soft film are mixed.

[0031] Commercially available products can be used as the silicone resin. As commercially available T-unit siloxanes, KR-500, KR-515, KC-89S, X-40-9225 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. can be used. As commercially available D-unit silicone resins, XF42-B0970, TSF410, TSF411 (manufactured by Momentive Performance Materials Japan G.K.), etc. can be used. As commercially available copolymer oligomers of T-unit siloxane and D-unit siloxane, X-40-9246, X-40-9250, X-88-1004, X-88-1007 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. can be used.

[0032] In addition, the silicone resin of the anti-fouling coating agent for aquatic organisms may contain M-unit siloxane and / or Q-unit siloxane as long as its performance is not impaired.

[0033] The disilanol compound contained in the anti-fouling coating agent for aquatic organisms in the embodiment is a silicone having silanol groups at both ends of the polysiloxane main chain. Since the silanol groups of the disilanol compound can bond (condensation reaction) with the silicone resin, it is also referred to as a silanol-reactive polymer.

[0034] The disilanol compound is composed of two silanol groups having compatibility with the silanol groups of T-unit siloxane and D-unit siloxane, which are the bonding structural units of the silicone resin, and a polysiloxane main chain having poor compatibility with the silanol groups of these bonding structural units. The bonding structural units (T-unit siloxane and D-unit siloxane) of the silicone resin contain a large number of silanol groups before the formation of the anti-fouling film 10, so they are compatible with the silanol groups at both ends of the disilanol compound and are hardly compatible with the polysiloxane main chain of the disilanol compound. In the film-forming process of the anti-fouling coating agent for aquatic organisms, since the polysiloxane main chain of the disilanol compound is hardly compatible with the bonding structural units of the silicone resin, it appears on the surface of the anti-fouling film 10 formed by the film formation of the anti-fouling coating agent for aquatic organisms. The two silanol groups at both ends of the polysiloxane main chain that appear on the surface of the anti-fouling film 10 bond with the siloxane units of the silicone resin, and the polysiloxane main chain connecting the two silanol groups is presumed to form a loop-shaped body 11 and cover the surface of the anti-fouling film 10. As shown in FIG. 1, the polysiloxane main chain that has become the loop-shaped body 11 forms an arc toward the outside of the anti-fouling film 10 and is capable of elastic deformation. For this reason, the anti-fouling film 10 formed from the anti-fouling coating agent for aquatic organisms can be peeled off immediately when the aquatic organism 3 adheres due to the elastic deformation of the loop-shaped body 11, so that the adhesion of the aquatic organism 3 can be prevented.

[0035] The polysiloxane main chain can be polydimethylsiloxane or a diphenylsiloxane-dimethylsiloxane copolymer. Polydimethylsiloxane or a diphenylsiloxane-dimethylsiloxane copolymer has a large water contact angle. The anti-adhesion film 10 formed from an anti-fouling coating agent for aquatic organisms is not well compatible with water, and it is considered that even if an aquatic organism 3 adheres, it will be peeled off immediately. The disilanol compound in which the polysiloxane main chain is polydimethylsiloxane is shown in the following structural formula (1), and the disilanol compound in which the polysiloxane main chain is a diphenylsiloxane-dimethylsiloxane copolymer is shown in the following structural formula (2).

[0036] [Chemical formula]

[0037] [Chemical formula]

[0038] The weight average molecular weight of the disilanol compound having a polysiloxane main chain (hereinafter, may be simply abbreviated as "average molecular weight") can be 100,000 to 150,000. This is because the anti-adhesion film 10 formed from an anti-fouling coating agent for aquatic organisms can prevent the adhesion of aquatic organisms 3. When the average molecular weight of the disilanol compound is less than 100,000, the loop-shaped body 11 formed from the polysiloxane main chain can only elastically deform slightly, and there is a risk that it cannot be peeled off when an aquatic organism 3 adheres, and there is a risk that the adhesion of the aquatic organism 3 cannot be prevented. On the other hand, when the average molecular weight of the disilanol compound exceeds 150,000, the loop-shaped body 11 formed from the polysiloxane main chain is too long and becomes a state of moving greatly, has adhesiveness, and there is a risk that an aquatic organism 3 will adhere due to the adhesiveness. As another embodiment, the average molecular weight of the disilanol compound can be 105,000 to 140,000, and as still another embodiment, it can be 110,000 to 130,000.

[0039] Commercially available dicyclolanol compounds can be used. As commercially available dicyclolanol compounds, X-21-5841, KF-9701, X-21-5847, X-21-5849 (manufactured by Shin-Etsu Chemical Co., Ltd.), XC96-723, YF3800, XF3905, YF3057, YF3807, YF3802, YF3897 (manufactured by Momentive Performance Materials Japan G.K.) and the like can be used.

[0040] When applying the anti-fouling coating agent of the embodiment to the ship bottom 1, a curing catalyst can be added to increase the curing rate of the anti-fouling film formed from the anti-fouling coating agent. As the curing catalyst, commercially available products such as oxides, phosphoric acids, amines or metals can be used. As another embodiment, a metal catalyst (titanium-based catalyst, aluminum-based catalyst) excellent in curing characteristics can be used as the curing catalyst. As still another embodiment, a titanium-based catalyst of the metal catalyst can be used, and among the titanium-based catalysts, a titanium organic metal compound-based catalyst (such as tetrabutyl titanate) can be used.

[0041] In addition, a diluent for adjusting the viscosity of the anti-fouling coating agent can be added to the anti-fouling coating agent. As the diluent, silicone-based diluents such as general-purpose silicone oil and hydrocarbon-based diluents such as paraffin-based and olefin-based diluents can be used.

[0042] The anti-fouling coating agent can be produced by mixing and stirring a silicone resin with a dicyclolanol compound and, if necessary, a diluent or the like. A general-purpose explosion-proof stirrer is used for stirring the anti-fouling coating agent. The curing catalyst is stored in a container separate from the container of the anti-fouling coating agent and mixed with the anti-fouling coating agent during painting.

[0043] The glass-based primer is a primer that is applied as a primer for an anti-fouling coating agent for underwater organisms, and forms a glass-based film 12 on the bottom 1 of a ship as an underwater structure.

[0044] The glass-based primer for forming the glass-based film 12 contains 5 to 20% by mass of silicone resin, 5 to 20% by mass of alkylalkoxysilane, and 60 to 85% by mass of diluent.

[0045] The silicone resin has a siloxane (Q-unit siloxane) represented by the formula (SiO 4 / 2 ) as a main constituent unit in the bonding structure unit, and optionally contains a siloxane represented by the formula (R 3 SiO 3 / 2 ) (hereinafter referred to as "T-unit siloxane") in the bonding structure unit.

[0046] The alkylalkoxysilane is composed of an alkylalkoxysilane (T-unit alkylalkoxysilane) represented by the formula ((R 5 O)3SiR 6 ) in the bonding structure unit.

[0047] The Q-unit siloxane (SiO 4 / 2 ) is an oligomer of a silane compound having four siloxane bond attachment points to silicon, and as a single structural unit, has a structure of "(R 4 O)4Si", and four alkoxy groups (R 4 O) undergo a hydrolysis and dehydration condensation reaction (polymerization) with the alkoxy groups of other Q-unit siloxanes, T-unit siloxanes, or T-unit alkylalkoxysilanes to form a film composed of hard siloxane bonds with a three-dimensional network structure. The condensation between Q-unit siloxanes forms a glassy film with a siloxane bond ((-Si-O-) n ) as the backbone. The Q-unit siloxane with a low degree of polymerization can enter the fine uneven shape on the surface of the bottom 1 of the ship and adhere firmly to the bottom 1 of the ship by the anchor effect. The alkoxy group (R 4(O) can be a methoxy group or an ethoxy group with fast hydrolysis and dehydration condensation reactions, and can be a methoxy group with faster reactions. Note that the Q-unit siloxane with a low degree of polymerization in the embodiment refers to one with a degree of polymerization of 5 to 15 (weight average molecular weight of 300 to 900).

[0048] Commercially available products can also be used as the Q-unit siloxane. As commercially available Q-unit siloxanes, MKC Silicate MS51, MS56, MS57, MS56S (manufactured by Mitsubishi Chemical Corporation), XIAMETER OFS-6697 Silane (manufactured by Dow Corning Toray Co., Ltd.), X-40-9238, X-40-2308 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. can be used.

[0049] The T-unit siloxane (R 3 SiO 4 / 2 ) is an oligomer of a silane compound having three siloxane bond attachment points to silicon and one alkyl group (R 3 ). By causing the attachment points of the three siloxane bonds to undergo hydrolysis and dehydration condensation reactions (polymerization) with the alkoxy groups of the Q-unit siloxane, T-unit siloxane, or T-unit alkylalkoxysilane, a film composed of hard siloxane bonds with a three-dimensional network structure is formed. Since the silicone resin of the glass-based undercoat contains the T-unit siloxane, the formed glass-based film 12 has flexibility due to the alkyl group (R 3 ) of the T-unit siloxane, and the durability of the glass-based film 12 can be enhanced. Since the T-unit siloxane is an oligomer, it is mixed as a microscopically soft film into the glass-based film 12 formed from the glass-based undercoat. The alkyl group (R 3 ) can be a C8 - C12 medium-chain alkyl group that can impart appropriate flexibility. Note that when the alkyl group (R 3 ) is a short-chain alkyl group with 7 or less carbon atoms, the glass-based film 12 formed from the glass-based undercoat does not have sufficient flexibility and may not be able to follow the deformation caused by vibrations of the ship bottom 1 of the ship, etc., and there is a risk of cracking. On the other hand, when the alkyl group (R 3) When it is a long-chain alkyl group with C13 or more, the glass-based coating film 12 formed from the glass-based undercoat agent has excessive flexibility, and there is a risk that the strength of the glass-based coating film 12 such as adhesion strength is inferior.

[0050] Commercially available products can also be used as the T-unit siloxane. As commercially available T-unit siloxanes, KR-500, KR-515, KC-89S, X-40-9225 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. can be used.

[0051] The T-unit alkylalkoxysilane is a silane compound having three alkoxy groups and one alkyl group on silicon, and the alkoxy group (R 5 O) enables copolymerization (dehydration condensation reaction) with silicone resins (Q-unit siloxane, T-unit siloxane), and as a single substance, it has the structure of "(R 5 O)3SiR 6 ". When the T-unit alkylalkoxysilane copolymerizes with the Q-unit siloxane, the glass-based coating film 12 formed from the glass-based undercoat agent has flexibility due to the alkyl group (R 6 ) of the T-unit alkylalkoxysilane and can follow the deformation of the base material of the ship bottom 1 without cracking. Different from the oligomeric T-unit siloxane, the T-unit alkylalkoxysilane is a single substance like a monomer, so flexibility can be uniformly imparted to the glass-based coating film 12 formed from the glass-based undercoat agent. The alkoxy group (R 5 O) of the T-unit alkylalkoxysilane can be a methoxy group or an ethoxy group with fast hydrolysis and dehydration condensation reaction, and can be a faster methoxy group. The alkyl group (R 6 ) of the T-unit alkylalkoxysilane can be a medium-chain alkyl group having C8 to C12 that can impart appropriate flexibility. Incidentally, the alkyl group (R 6) When the short-chain alkyl group is C7 or less, the glass-based film 12 formed from the glass-based undercoat may not have sufficient flexibility and may not be able to follow the deformation due to vibrations of the ship bottom 1 of the ship, etc., and may crack. On the other hand, when the alkyl group (R 6 ) of the T-unit alkylalkoxysilane is a long-chain alkyl group of C13 or more, the glass-based film 12 formed from the glass-based undercoat has excessive flexibility, and there is a possibility that the strength of the glass-based film 12, such as the adhesion strength, is inferior.

[0052] Commercially available products can also be used as the T-unit alkylalkoxysilane. As commercially available T-unit alkylalkoxysilanes, DOWSIL Z-6341 Silane (n-C8H 17 Si(OC2H5)3), DOWSIL Z-6210 Silane (n-C 10 H 21 Si(OCH3)3) (manufactured by Dow Corning Toray Co., Ltd.), KBE-3083 (n-C8H 17 Si(OC2H5)3), KBM-3103C (n-C 10 H 21 Si(OCH3)3) (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. can be used.

[0053] The glass-based undercoat contains 60 to 85% by mass of a diluent. More specifically, the diluent is composed of a volatile silicone oil and an alcohol, and contains 20 to 60% by mass of the volatile silicone oil and 20 to 60% by mass of the alcohol with respect to the total amount of the glass-based undercoat. By the glass-based undercoat containing a diluent, the Q-unit siloxane with a low degree of polymerization is diluted with the diluent and enters the fine uneven shape on the surface of the ship bottom 1 of the ship, and can adhere firmly to the ship bottom 1 by the anchor effect.

[0054] As the volatile silicone oil to be contained in the glass-based undercoat agent, chain siloxane, cyclic siloxane, and dimethylpolysiloxane can be used. As another embodiment, decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), which are cyclic siloxanes with high volatility, can be used. As yet another embodiment, decamethylcyclopentasiloxane (D5) can be used. The kinematic viscosity (25°C) of the volatile silicone oil can be 5 mm 2 / s or less. If it exceeds 5 mm 2 / s, there is a risk that the silicone oil will not volatilize. As another embodiment, the kinematic viscosity (25°C) of the volatile silicone oil can be 0.65 to 2 mm 2 / s.

[0055] As the alcohol to be contained in the glass-based undercoat agent, a mixture of C2-C12 alcohols can be used. This is because the volatility of the diluent can be made suitable. When the alcohol contained in the glass-based undercoat agent is C1 alcohol (methanol), the diluent volatilizes quickly, and there is a risk that the workability of the glass-based undercoat agent will be poor. On the other hand, when the alcohol contained in the glass-based undercoat agent is an alcohol with a molecular weight exceeding C12 alcohol (dodecanol), the diluent volatilizes slowly, and there is a risk that the workability of the glass-based undercoat agent will be poor.

[0056] A curing catalyst can be added to the glass-based undercoat agent to accelerate curing. The curing catalyst may be any one that can accelerate the curing reaction of the Q-unit siloxane and the T-unit alkylalkoxysilane, which are components for forming the glass-based film 12 of the glass-based undercoat agent. Commercially available products such as oxides, phosphates, amines, or metals can be used. As another embodiment, a metal catalyst (titanium-based catalyst, aluminum-based catalyst) with excellent curing characteristics can be used as the curing catalyst. As yet another embodiment, a titanium-based catalyst among metal catalysts can be used, and among titanium-based catalysts, a titanium organometallic compound-based catalyst (such as tetrabutyl titanate) can be used.

[0057] The curing catalyst can be added to the glass-based undercoat in an amount of 0.5 to 5% by mass. This is because the curability of the glass-based undercoat can be suitably improved. If the addition amount of the curing catalyst to the glass-based undercoat is less than 0.5% by mass, there is a possibility that the curability of the glass-based undercoat cannot be suitably improved. On the other hand, if it exceeds 5% by mass, it becomes an excessive addition amount and may be uneconomical. As another embodiment, the content of the curing catalyst in the glass-based undercoat can be 0.8 to 2% by mass.

[0058] When the glass-based undercoat contains a curing catalyst, it can be a two-component material (main agent and curing agent) in which the curing catalyst is mixed with the glass-based undercoat immediately before application. By using a two-component material, the glass-based undercoat can suppress the promotion of curing during storage of the material. In this case, the main agent can be a mixture of Q-unit siloxane, T-unit siloxane, and alkylalkoxysilane, and the curing agent can be a mixture of a curing catalyst and a diluent.

[0059] The surface modification method of the bottom 1 of a ship as an underwater structure according to the embodiment includes a glass-based film forming step in which a glass-based undercoat is applied to the surface of the bottom 1 of the ship to form a glass-based film 12, and an adhesion prevention film forming step in which an underwater biofouling prevention coating agent is applied to the formed glass-based film 12 to form an adhesion prevention film 10.

[0060] When the ship's bottom 1 is a newly built ship, the bottom 1 is washed with warm water or the like, and if necessary, roughened with sandpaper or the like, and then used for painting. When the ship is a ship that has already sailed, the crustaceans, shellfish, or algae attached to the bottom 1 are removed with a scraper or the like, the oil stain or the like is wiped off with a thinner, and after washing the bottom 1, it is used for painting.

[0061] The glass-based film forming step is a step of spray coating a glass-based undercoat containing a silicone resin, an alkylalkoxysilane, and a diluent, and a curing agent containing a diluent and a curing catalyst on the bottom 1 of the ship.

[0062] The glass-based primer and the curing agent are mixed immediately before spray coating, and can be applied by spraying using a general-purpose spray gun or by brush coating. Also, the glass-based primer and the curing agent can be applied using an aerosol such as a mixing spray gun or a spray can that can mix the main agent and the curing agent during spraying. As the mixing spray gun, WA-200-S6, SG-496B (manufactured by Anest Iwata Corporation), etc. can be used.

[0063] The coating amount of the glass-based primer and the curing agent is the coating amount in the wet state (Wet) of the glass-based primer, and can be 30 to 150 g / m 2 This is because a sufficient film thickness can be ensured. When the coating amount of the glass-based primer and the curing agent is less than 30 g / m in the coating amount in the wet state of the glass-based primer, there is a possibility that it may be partially uncoated and the effect of the glass-based film 12 cannot be exhibited. On the other hand, when it exceeds 150 g / m 2 there is a possibility that the applied glass-based primer and curing agent may drip and flow. As another embodiment, the coating amount of the glass-based primer and the curing agent can be 50 to 120 g / m in the coating amount in the wet state of the glass-based primer, and as yet another embodiment, it can be 70 to 100 g / m 2 2 2 Since the glass-based primer can exhibit its effect by being covered with the glass-based film 12 formed from the glass-based primer on the bottom of the ship 1, even if the excess glass-based primer is wiped off with a cloth or the like after coating, the effect of the glass-based primer can be exhibited. Also, even when the glass-based primer is applied with an excessive coating amount, since a film can be formed by the volatilization of the diluent, the effect of the glass-based primer can be exhibited without wiping off the excessive glass-based primer. 2

[0064] The glass-based primer (and hardener) applied to the ship bottom 1 initiates the bonding through the dehydration condensation of the oligomers of the siloxane of the silicone resin. Since the silicone resin is composed of Q-unit siloxanes, it forms a hard coating. By including T-unit siloxanes in addition to the Q-unit siloxanes in the silicone resin, a partially flexible coating can be formed. Also, the oligomers of the siloxane of the silicone resin and the T-unit alkylalkoxysilane are bonded through dehydration condensation, and the alkyl group (R 6 ) of the T-unit alkylalkoxysilane imparts flexibility to the hard coating.

[0065] The antifouling coating formation process is a process of spray coating an antifouling coating agent for aquatic organisms containing a silicone resin and a disilanol compound, and a hardener containing a diluent and a curing catalyst, onto the ship bottom 1 of a ship or the glass-based coating 12 formed on the ship bottom 1. Note that even when the glass-based coating 12 is in an uncured state, the antifouling coating agent for aquatic organisms (and hardener) can be spray coated. This is because the silicone resin of the antifouling coating agent for aquatic organisms can be bonded to the silicone resin of the glass-based primer through dehydration condensation. Of course, the antifouling coating agent for aquatic organisms (and hardener) can also be applied to the glass-based coating 12 in a state where the glass-based primer (and hardener) has hardened and can adhere to the glass-based coating 12. Note that the antifouling coating agent for aquatic organisms (and hardener) and the glass-based primer (and hardener) each reach a touch-dry state in 1 to 6 hours.

[0066] Similar to the glass-based primer, the antifouling coating agent for aquatic organisms and the hardener are mixed immediately before spray coating, and can be applied by painting with a general-purpose spray gun or by brush painting, or by using a mixing spray gun or aerosol that can mix the main agent and the hardener during spraying.

[0067] The coating amount of the antifouling coating agent for aquatic organisms and the hardener is the coating amount in the wet state (Wet) of the antifouling coating agent for aquatic organisms, which is 30 to 150 g / m2 This can be achieved because a sufficient film thickness can be ensured. When the coating amount of the anti-fouling coating agent for aquatic organisms and the curing agent is less than 30 g / m² in terms of the coating amount in the wet state of the anti-fouling coating agent for aquatic organisms, 2 the film thickness may become too thin or there may be partial non-coating, and there is a risk that the effect of the anti-fouling film 10 cannot be exerted. On the other hand, when it exceeds 150 g / m², 2 there is a risk that the applied anti-fouling coating agent for aquatic organisms and the curing agent may drip and flow, and there is also a risk that the effect of the anti-fouling film 10 cannot be exerted. As another embodiment, the coating amount of the anti-fouling coating agent for aquatic organisms and the curing agent can be 50 to 120 g / m² in terms of the coating amount in the wet state of the anti-fouling coating agent for aquatic organisms, 2 and as yet another embodiment, it can be 70 to 100 g / m². 2 It should be noted that the anti-fouling coating agent for aquatic organisms does not require wiping off with a cloth or the like after coating.

[0068] The anti-fouling coating agent (and curing agent) applied to the glass film 12 or the ship bottom 1 initiates the bonding by the dehydration condensation of the oligomers of the T-unit siloxane and D-unit siloxane of the silicone resin. Since the silicone resin is composed of the T-unit siloxane and D-unit siloxane, the anti-fouling film 10 can form a flexible film. The disilanol compound contained in the anti-fouling coating agent for aquatic organisms has silanol groups at both ends participating in the bonding by the dehydration condensation of siloxane, and both ends are bonded to the structural units of siloxane. Also, in the state of the anti-fouling coating agent for aquatic organisms (anti-fouling film 10) immediately after application, a polysiloxane main chain with poor compatibility with the silicone resin appears on the surface of the anti-fouling film 10. Therefore, the disilanol compound has both ends bonded to the structural units of siloxane, and the polysiloxane main chain appears on the surface of the anti-fouling film 10, forming the loop-shaped body 11. Since the polysiloxane main chain that has become the loop-shaped body 11 forms an arc outward, the anti-fouling film 10 with the loop-shaped body appearing on the surface can be easily peeled off even when crustaceans, shellfish, or algae adhere due to the elastic deformation of the loop-shaped body 11, thus preventing the adhesion of crustaceans, shellfish, or algae.

Example

[0069] Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, an anti-fouling coating agent with different formulations and a glass-based primer were applied to the surface of a 60 cm × 60 cm FRP plate to prepare test specimens, and the test specimens were exposed to the sea at a depth of 1 m off the coast of Nagoya Port for one year, and the evaluation tests described below were conducted.

[0070] Adhesion test of aquatic organisms For the adhesion test of aquatic organisms, for the test specimens exposed to the sea for one year, the adhesion of aquatic organisms 3 (such as crustaceans, shellfish, or algae) was visually confirmed. Then, those where no adhesion of aquatic organisms 3 could be confirmed on the painted surface (anti-adhesion film 10) were marked as ○, those where adhesion of aquatic organisms 3 could be confirmed on 20% or less of the painted surface (50 or less in terms of the number of barnacles) were marked as △, and those where adhesion of aquatic organisms 3 could be confirmed on more than 20% of the painted surface (more than 50 in terms of the number of barnacles) were marked as × for evaluation.

[0071] Durability test of the film For the durability test of the film, for the test specimens exposed to the sea for one year, the occurrence of abnormalities (such as swelling, peeling, etc.) of the anti-adhesion film 10 was visually confirmed. Then, those where no abnormalities could be confirmed in the anti-adhesion film 10 were marked as ○, those where abnormalities could be confirmed in 20% or less of the area of the anti-adhesion film 10 were marked as △, and those where abnormalities could be confirmed in more than 20% of the area of the anti-adhesion film 10 were marked as × for evaluation.

[0072] The details of the silicone resin used in the anti-aquatic-organism adhesion coating agent of the test example are described in Table 1. Silicone resin A is an oligomer composed of T-unit siloxane, and silicone resin E is an oligomer composed of D-unit siloxane. Silicone resins B - D are copolymer oligomers formed by the copolymerization of T-unit siloxane and D-unit siloxane.

[0073]

Table 1

[0074] The details of the disilanol compound used in the anti-aquatic-organism adhesion coating agent of the test example are described in Table 2. Disilanol compounds A - D are those with the weight-average molecular weight of the polysiloxane main chain of the disilanol compound changed.

[0075]

Table 2

[0076] The formulations of glass-based undercoat A and glass-based undercoat B used as the undercoat for the anti-fouling coating agent in the test examples are described in Table 3 and Table 4, respectively. The oligomers of Q units (and T units) of siloxane, T unit alkylalkoxysilane, and volatile silicone oil are mixed to form the main component of the glass-based undercoat, and alcohol and titanium-based catalyst are mixed to form the curing catalyst of the glass-based undercoat. The main component and the curing catalyst of the glass-based undercoat can be mixed using a mixing spray gun that can mix the main component and the curing agent during spraying, and at the ratio of the formulation amounts in Table 3 or Table 3, at a coating amount of 80 g / m 2 (in the Wet state including volatile components), it was applied to the FRP plate of the test substrate.

[0077]

Table 3

[0078]

Table 4

[0079] The results of the test examples and the evaluation tests are described in Table 5. Test examples 2, 3, 6 to 8, and 10 to 14 are examples, and test examples 1, 4, 5, 9, and 15 are comparative examples. Table 5 describes the formulation of the anti-fouling coating agent in the test examples. The silicone resin and the disilanol compound are mixed to form the main component of the anti-fouling coating agent, and the diluent and the titanium-based catalyst are mixed to form the curing catalyst of the anti-fouling coating agent. The main component and the curing catalyst of the anti-fouling coating agent can be mixed using a mixing spray gun that can mix the main component and the curing agent during spraying, and at the ratio of the formulation amounts in Table 5, at a coating amount of 80 g / m 2 (in the Wet state including volatile components), it was applied to the coated surface of the test substrate coated with the glass-based undercoat.

[0080]

Table 5

[0081] The anti-fouling coating agents for aquatic organisms in Test Examples 1 to 4 used a copolymer oligomer of silicone resin C with a T-unit siloxane:D-unit siloxane = 70:30 (molar ratio) as described in Table 1 in the silicone resin, and used dicyclanol compounds A to D with the weight average molecular weight of the polysiloxane main chain of the dicyclanol compounds changed as described in Table 2 in the dicyclanol compounds, respectively, as the main agent of the mixed anti-fouling coating agent for aquatic organisms. The curing catalyst of the anti-fouling coating agent for aquatic organisms was a curing catalyst obtained by mixing the diluent and the titanium-based catalyst described in Table 5. As the glass-based undercoat, Glass-based Undercoat A described in Table 3 was used.

[0082] (Test Example 1) Test Example 1 is a test example in which dicyclanol compound A with a weight average molecular weight of 77,000 as described in Table 2 was used in the dicyclanol compound. For the specimens exposed to the sea for one year, although no abnormalities were found in the adhesion prevention film 10 in the film durability test, in the adhesion test of aquatic organisms, the adhesion of aquatic organisms 3 exceeding 20% of the painted surface was confirmed, and it was inferior in the adhesion of aquatic organisms 3. In Test Example 1, it is presumed that the average molecular weight of the dicyclanol compound was small, and the loop-shaped body 11 formed from the polysiloxane main chain could hardly be elastically deformed, resulting in a state where aquatic organisms 3 were likely to adhere.

[0083] (Test Examples 2 and 3) Test Example 2 is a test example in which the disilanol compound B with a weight average molecular weight of 110,000 described in Table 2 was used for the disilanol compound. Test Example 3 is a test example in which the disilanol compound C with a weight average molecular weight of 150,000 described in Table 2 was used for the disilanol compound. In each case, for the test specimens exposed to the sea for one year, no abnormality was confirmed in the adhesion prevention film 10 in the film durability test, and no adhesion of the aquatic organism 3 was confirmed on the painted surface in the adhesion test of the aquatic organism. They were excellent in film durability and adhesion of the aquatic organism. In Test Examples 2 and 3, the silicone resin was excellent in the balance of the molar ratio of the T-unit siloxane and the D-unit siloxane, had appropriate flexibility, was excellent in protectiveness as a film, and the disilanol compound was able to elastically deform moderately and was presumably in a state where it would be peeled off immediately even if the aquatic organism 3 adhered.

[0084] (Test Example 4) Test Example 4 is a test example in which the disilanol compound D with a weight average molecular weight of 180,000 described in Table 2 was used for the disilanol compound. For the test specimen exposed to the sea for one year, although no abnormality was confirmed in the adhesion prevention film 10 in the film durability test, adhesion of the aquatic organism 3 was confirmed on 20% or less of the painted surface in the adhesion test of the aquatic organism, and the adhesion of the aquatic organism was slightly inferior. In Test Example 4, the average molecular weight of the disilanol compound was large, and the loop-shaped body 11 formed from the polysiloxane main chain was in a state of moving greatly because it was too long, had adhesiveness, and it is presumed that this was the cause of the adhesion of the aquatic organism 3 due to the adhesiveness.

[0085] The anti-fouling coating agents in Test Examples 5 to 9 used, in the silicone resin, silicone resin A which is an oligomer composed of T-unit siloxane described in Table 1, silicone resins B to D which are copolymer oligomers with the molar ratio of T-unit siloxane:D-unit siloxane changed as described in Table 1, and silicone resin E which is an oligomer composed of D-unit siloxane, respectively, and used, in the disilanol compound, disilanol compound C with a weight average molecular weight of 150,000 described in Table 2, and made them the main agent of the mixed anti-fouling coating agent. Note that silicone resins B to D are copolymer oligomers. The curing catalyst of the anti-fouling coating agent was a curing catalyst in which the diluent described in Table 5 and the titanium-based catalyst were mixed. As the glass-based undercoat, glass-based undercoat B described in Table 4 was used.

[0086] (Test Example 5) Test Example 5 is a test example in which silicone resin A which is an oligomer composed of T-unit siloxane described in Table 1 was used in the silicone resin. For the test specimens exposed to the sea for one year, in the coating durability test, the occurrence of abnormalities (cracks and peeling from cracks) of 20% or less of the area of the anti-fouling coating 10 could be confirmed, and in the underwater bioadhesion test, the adhesion of underwater organisms 3 of 20% or less of the painted surface could be confirmed, and the coating durability and the underwater bioadhesion were slightly inferior. In Test Example 5, since silicone resin A which is an oligomer composed of T-unit siloxane was used in the silicone resin, the anti-fouling coating 10 was hard, and the anti-fouling coating 10 could not follow the movement of the test specimen, resulting in cracks and peeling, and it is presumed that this was the reason why underwater organisms 3 easily adhered to the cracks and peeling.

[0087] (Test Examples 6 to 8) Test Example 6 is a test example in which silicone resin B, a copolymer oligomer consisting of T unit siloxane:D unit siloxane = 90:10 as shown in Table 1, was used as the silicone resin. Test Example 7 is a test example in which silicone resin C, a copolymer oligomer consisting of T unit siloxane:D unit siloxane = 70:30 as shown in Table 1, was used as the silicone resin. Test Example 8 is a test example in which silicone resin D, a copolymer oligomer consisting of T unit siloxane:D unit siloxane = 60:40 as shown in Table 1, was used as the silicone resin. In each of the test specimens exposed in the sea for one year, no abnormality was observed in the adhesion prevention coating 10 in the coating durability test, and no adhesion of aquatic organisms 3 was observed on the coating surface in the aquatic organism adhesion test, showing that the coating had excellent durability and adhesion to aquatic organisms. In test examples 6 to 8, it is presumed that the silicone resin had an excellent balance of the molar ratio of T unit siloxanes and D unit siloxanes, had moderate flexibility, and provided excellent protective properties as a coating, and the disilanol compound was capable of moderate elastic deformation, and was in a state in which even if aquatic organisms 3 attached, they would be quickly peeled off.

[0088] (Test Example 9) Test Example 9 is a test example in which silicone resin E, an oligomer consisting of D-unit siloxane, as shown in Table 1, was used as the silicone resin. In the coating durability test of the test specimen exposed to the sea for one year, the occurrence of abnormalities (blistering) exceeding 20% ​​of the area of ​​the adhesion prevention coating 10 was confirmed, but in the aquatic organism adhesion test, no adhesion of aquatic organisms 3 was confirmed, and only the durability of the coating was slightly inferior. In Test Example 5, silicone resin E, an oligomer consisting of D-unit siloxane, was used as the silicone resin, so it is presumed that the anti-adhesion coating 10 had flexibility, and the intrusion of seawater 2 caused the anti-adhesion coating 10 to blister.

[0089] The anti-fouling coating agents of Test Examples 10 to 13 used a mixed oligomer obtained by mixing silicone resin A composed of T-unit siloxane and silicone resin E composed of D-unit siloxane described in Table 1 with different ratios in silicone resin, and used dicyclanol compound B with a weight average molecular weight of 110,000 described in Table 2 as the main component of the mixed anti-fouling coating agent. The curing catalyst of the anti-fouling coating agent was a curing catalyst obtained by mixing the diluent and titanium-based catalyst described in Table 5. As the glass-based undercoat, glass-based undercoat B described in Table 4 was used.

[0090] (Test Example 10) Test Example 10 is a test example in which a mixed oligomer (that is, T-unit siloxane: D-unit siloxane = 95: 5) obtained by mixing silicone resin A and silicone resin E in a ratio of silicone resin A: silicone resin E = 57: 3 was used in silicone resin. For the test specimens exposed to the sea for one year, in the coating durability test, abnormal occurrences (cracks and peeling from cracks) of 20% or less of the area of the anti-fouling coating 10 could be confirmed, and in the underwater biofouling test, the adhesion of underwater organisms 3 of 20% or less of the painted surface could be confirmed. The durability of the coating and the adhesion of underwater organisms were slightly inferior.

[0091] (Test Examples 11 and 12) Test Example 11 is a test example in which a mixed oligomer (that is, T-unit siloxane: D-unit siloxane = 90: 10) obtained by mixing silicone resin A and silicone resin E in a ratio of silicone resin A: silicone resin E = 54: 6 was used in silicone resin. Test Example 12 is a test example in which a mixed oligomer (that is, T-unit siloxane: D-unit siloxane = 60: 40) obtained by mixing silicone resin A and silicone resin E in a ratio of silicone resin A: silicone resin E = 36: 24 was used in silicone resin. For each of the test specimens exposed to the sea for one year, in the coating durability test, no abnormal occurrences could be confirmed in the anti-fouling coating 10, and in the underwater biofouling test, no adhesion of underwater organisms 3 could be confirmed on the painted surface. They were excellent in the durability of the coating and the adhesion of underwater organisms.

[0092] (Test Example 13) Test Example 13 is a test example in which a mixed oligomer (i.e., T-unit siloxane:D-unit siloxane = 10:90) mixed with silicone resin A:silicone resin E at a ratio of 6:54 is used in the silicone resin. For the test specimens exposed to the sea for one year, in the coating durability test, an abnormality (swelling) of 20% or less of the area of the adhesion-preventing coating 10 was confirmed. However, in the adhesion test of underwater organisms, no adhesion of underwater organisms 3 was confirmed, and only the durability of the coating was slightly inferior. In Test Example 13, it is presumed that the adhesion-preventing coating 10 has flexibility and swelling occurred in the adhesion-preventing coating 10 due to the intrusion of seawater 2.

[0093] (Test Example 14) Test Example 14 is a test example in which the application of the glass-based undercoat is omitted from Test Example 7. By omitting the application of the glass-based undercoat, it was confirmed that the underwater organism adhesion-preventing coating agent has poor adhesion to the FRP plate, and in the coating durability test, an abnormality (swelling) of 20% or less of the area of the adhesion-preventing coating 10 was confirmed.

[0094] (Test Example 15) Test Example 15 is for an FRP plate with an unmodified (unpainted) surface that was exposed to the sea for one year. In the adhesion test of underwater organisms, adhesion of underwater organisms 3 exceeding 20% of the painted surface was confirmed, and it was inferior in the adhesion of underwater organisms.

Explanation of Reference Numerals

[0095] 1…Ship bottom, 2…Seawater, 3…Underwater organisms, 10…Adhesion-preventing coating, 11…Loop-shaped body, 12…Glass-based coating.

Claims

1. comprising a silicone resin and a disilanol compound, the silicone resin contains, in a molar ratio, a siloxane represented by the formula (R 1 SiO 3 / 2 ), hereinafter referred to as "T-unit siloxane", and a siloxane represented by the formula (R 2 2 SiO 2 / 2 ), hereinafter referred to as "D-unit siloxane", in a molar ratio of the T-unit siloxane: the D-unit siloxane = 10:90 to 95:5, the disilanol compound has a weight average molecular weight of 100,000 to 150,000, has silanol groups at both ends of the molecule, and the main chain is polydimethylsiloxane or a diphenylsiloxane-dimethylsiloxane copolymer, and is a coating agent for preventing adhesion of aquatic organisms.

2. The anti-fouling coating agent for preventing adhesion of aquatic organisms according to claim 1, wherein the silicone resin contains the T-unit siloxane and the D-unit siloxane in a molar ratio of 60:40 to 90:

10.

3. The anti-fouling coating agent for preventing adhesion of aquatic organisms according to claim 1, which is a combination with a curing catalyst.

4. A surface modification method for modifying the surface of the bottom of a ship with an anti-fouling coating agent for preventing adhesion of aquatic organisms, a glass-based undercoat is applied to the surface of the bottom of the ship to form a glass-based film in a glass-based film forming step, the anti-fouling coating agent according to claim 1 is applied to the formed glass-based film to form an anti-fouling film in an anti-fouling film forming step, and the surface modification method of the bottom of the ship is characterized by having these steps.

5. The glass-based undercoat contains 5 to 20% by mass of a silicone resin, 5 to 20% by mass of an alkylalkoxysilane, and 60 to 85% by mass of a diluent, the silicone resin has, in a bonding structural unit, a formula (SiO 4 / 2 The method for surface modification of a ship bottom according to claim 4, comprising containing a siloxane represented by (hereinafter referred to as "Q-unit siloxane").

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