JPH10204335A - Underwater antifouling coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating compsn. that effectively prevents the growth of marine organisms on underwater shells, etc., of ships for a long term and is excellent in terms of environmental protection, by compounding a photocatalytic metal oxide powder (pref. anatase titanium oxide) and a binder. SOLUTION: A photocatalyst powder excited by the sunlight near the surface of a coating film oxidizes or reduces a binder surrounding it, causing the binder to be decomposed, dissolved into sea water, and thus separated. The bactericidal action of the particles of the photocatalyst powder with their heads projected out of the coating film surface prevents the growth of marine organisms for a long term. Anatase titanium oxide is pref. as the photocatalyst powder, and its pref. average particle size is 0.003-0.05μm. A vinyl resin, a polyester resin, a chlorinated rubber, etc., can be used as the binder. The coating compsn. is prepd. by compounding 20-85wt.% (pref. 40-75wt.%) photocatalyst powder with 10-60wt.% (pref. 25-50wt.%) binder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater antifouling paint composition which can effectively prevent the underwater organisms from adhering.

[0002]

2. Description of the Related Art Various types of marine organisms adhere to the outer skin of ships below sea level, marine structures, fishing nets, and other surfaces, which hinders efficient operation of ships. Problems such as extremely shortened service life occur in articles and fishing nets. As a countermeasure, an underwater antifouling paint composition containing various antifouling agents is applied. Typical antifouling paints used in the past include antifouling vehicle components consisting of a binder consisting of resins such as vinyl resins, alkyd resins, and chlorinated rubber that are insoluble in seawater, and a rosin that is soluble in seawater. Insoluble matrix-type antifouling paint containing a dispersing agent or a copolymer containing a triorganotin-containing monomer that gradually hydrolyzes in seawater as a vehicle component, and a dissolving matrix containing an antifouling agent as necessary Type antifouling paint.

[0003] However, the insoluble matrix-type antifouling paint which elutes the antifouling agent together with rosin into seawater and exhibits an antifouling effect cannot be expected to have a stable antifouling effect for a long period of time. Elutes, the resin component insoluble in seawater remains as a coating film and forms a skeleton structure.In particular, when applied to ships, the frictional resistance between seawater and the coated surface increases, the speed decreases, and fuel consumption decreases. However, there was a problem such as an increase in On the other hand, the dissolving matrix type antifouling paint has an antifouling effect, but has problems in health and safety and environmental conservation based on tin. Recently, antifouling paints containing a hydrolyzable resin containing no organotin and an antifouling agent have been developed. Since the antifouling paint does not contain organotin, the problem of safety and health has been solved, but there is a problem that the hydrolysis has a high temperature dependence and therefore the hydrolysis rate is difficult to adjust. Was.

[0004]

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of the conventional antifouling paints as described above, and is used for the outer panels of ships below sea level, marine structures, fishing nets, and the like. An object of the present invention is to provide a coating composition which can effectively prevent various marine organisms from adhering to the surface for a long period of time, and is excellent in safety and health and environmental protection.

[0005]

Means for Solving the Problems The inventors of the present invention have studied to overcome such a situation, and as a result, have found that a metal oxide powder having photocatalytic activity without containing organotin is compounded. Accordingly, the present invention has been found that a coating composition having a long-term antifouling property, excellent in safety and health and environmental protection, and hard to form a skeleton structure can be obtained, thereby completing the present invention. That is, the present invention provides an underwater antifouling paint composition containing a metal oxide powder having photocatalytic activity and a binder.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The photocatalytic activity of a metal oxide powder having photocatalytic activity (hereinafter simply referred to as “photocatalytic powder”), which is a component of the coating composition of the present invention, refers to sunlight (particularly ultraviolet light) in which the powder has energy equal to or more than its band cap. ) Is excited by absorbing the), the generated electrons and holes are the activity of oxidizing or reducing the substance in contact with the photocatalyst powder to decompose. In the present invention, the photocatalyst powder that has largely absorbed sunlight near the surface of the formed coating film is decomposed by oxidizing or reducing the binder near the periphery, and is dissolved or dropped in seawater. Since the photocatalyst powder caught on the surface of the coating film in this way has a bactericidal effect and the like, it prevents the underwater organisms from adhering. In addition, the photocatalyst powder caught in this manner is
In order to decompose the binder near the periphery, it is dropped off and the lower photocatalyst powder is excited, and this process is repeated in the same manner to prevent the adhesion of aquatic organisms for a long time.

As described above, since the photocatalyst powder gradually decomposes and dissolves or drops off the binder, it is difficult to form a skeleton structure like a conventional insoluble matrix-type antifouling paint, and it does not contain any organotin. It does not contain any antifouling agent or requires only a small amount to use, so that problems on health and safety and environmental conservation are solved. As the photocatalyst powder used in the present invention, for example, anatase type titanium oxide (Ti
O ₂ ), zinc oxide (ZnO), vanadium oxide (V ₂ O ₅ ), tungsten oxide (WO ₃ ), rubidium oxide (RuO ₂ ) and the like are typical examples. Excellent anatase-type titanium oxide is preferred. The average particle size of the photocatalyst powder is 0.001 to 0.8 μm, preferably 0.0 to increase the surface area and the photocatalytic activity.
Those having a size of 03 to 0.05 μm are suitable.

[0008] As the binder used in the present invention,
From insoluble matrix type antifouling paint and hydrolysis type antifouling
Various binders commonly used in paints can be used without particular limitation.
Can be used. Specifically, as a seawater-insoluble resin, vinyl
Resin, polyester resin, alkyd resin, fluorine tree
Fat, silicone resin, chlorinated rubber, etc. are typical
No. Further, as a hydrolysis type resin, JP-A-7-8
(B) No. 2512 and JP-A-7-82513
Xylic acid and / or its condensate, (ii) containing no hydroxyl group
Polycarboxylic acids and / or acid anhydrides thereof, and (c)
Polyester tree obtained by reacting polyhydric alcohol
Fat or polyester resin to vinyl resin
Resin; side chain terminal described in JP-A-8-3484
A resin having the following group at the end; -CO-OM-O-Si (R)_Three (Wherein, M represents a zinc atom or a copper atom, and R represents hydrogen
Atom, halogen atom, hydroxyl group, organo (poly) siloxy
It represents a sun group or a silyl group. The following groups are present at the side chain terminals described in JP-A-62-57464.
-CO-O-M-R (wherein M represents a zinc atom or a copper atom, and R represents -O
COR₁, -SCS-R ₁Or -OR₁And R₁Is
Shows a monovalent organic residue. ); JP-A-1-306479
Acetoxy group or ketoxime
Obtained by reacting a silane compound containing a group
Group-containing vinyl copolymers; described in JP-A-4-264170
The general formula of

[0009]

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(Wherein, R _{1 to} R ₄ represent an alkyl group or an aryl group) or a copolymer of the monomer and a vinyl monomer;
General formula described in No. 39 gazette,

[0011]

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(Wherein X ₁ and X _{2 each} represent a hydrogen atom or a methyl group, and Y ₁ and Y _{2 each} represent an alkyl group, an alkoxy group or a phenyl group), or Typical examples thereof include a copolymer of the monomer and a vinyl monomer. Other, Japanese Patent Application 7-28
No. 9548, a hydrophilic vinyl resin having a carboxyl group and having an acid value of 50 to 250, and the like. In the case where a seawater-insoluble resin is used in the present invention,
It dissolves or falls off only by the action of the photocatalyst powder, and when a hydrolyzable resin or hydrophilic resin is used, it dissolves or falls off by both the action of the resin itself and the action of the photocatalyst powder. The underwater antifouling coating composition of the present invention contains the photocatalyst powder and the binder described above as essential components, and if necessary, conventionally used antifouling agents, solvents, plasticizers, extender pigments, coloring pigments , Various additives, for example, an antifoaming agent, an anti-settling agent,
A leveling agent and the like can be appropriately compounded.

For example, antifouling agents include cuprous oxide, basic copper carbonate, copper thiocyanate, copper hydroxide, cuprous rhodan,
Manganese ethylene bisdithiocarbamate, zinc dimethyldithiocarbamate, zinc ethylenebisdithiocarbamate, zinc 2-pyridinethiol-1-oxide, 2-methylthio-4-t-butylamino-6-cyclopropylamino-s-triazine, 2, 4,5,6
-Tetrachloroisophthalonitrile, N, N-dimethylchlorophenylurea, 4,5-dichloro-2-N-octyl-3 (2H) isothiazolone, N- (fluorodichloromethylthio) phthalimide, N, N-dimethyl-
N'-phenyl (N-fluorodichloromethylthio) sulfamide, tetramethylthiuram disulfide, N
-(3,4-dichlorophenyl) -N, N-dimethylurea, 2,4,6-trichlorophenylmaleimide and the like.

The underwater antifouling coating composition of the present invention contains 20 to 85% by weight, preferably 40 to 85% by weight of a photocatalyst powder in the solid content of the coating composition.
75% by weight and 10 to 60% by weight of binder, preferably 2%
It is appropriate to comprise 5 to 50% by weight. The antifouling paint composition of the present invention is prepared by mixing or dispersing the above-mentioned components collectively or separately in a usual paint production apparatus such as a ball mill or disperser. The antifouling coating composition of the present invention thus prepared, as it is, or after adjusting the viscosity with a solvent, airless spray coating, air spray coating,
It is applied to ships and marine structures by roller coating, brush coating, etc. The antifouling coating composition of the present invention is preferably applied so as to have a thickness of about 30 μm to 300 μm after drying.

[0015]

The present invention will be described in more detail with reference to the following examples. In the examples, “parts” and “%” are based on weight. <Preparation of seawater-insoluble resin>
After charging 0 parts and raising the temperature to 110 ° C., a mixture consisting of 53.8 parts of methyl methacrylate, 46.2 parts of butyl acrylate and 1.0 part of azobisisobutyronitrile was added dropwise over 3 hours. 5 hours reaction, weight average molecular weight 28,00
0, a resin solution (A) having a solid content of 50% was prepared. Examples 1-4 and Comparative Examples 1-2 The components (units: parts) shown in Table 1 below were kneaded and dispersed to produce antifouling paints of Examples 1-4 and Comparative Examples 1-2. Each of these antifouling paints was applied by air spray coating on a steel sheet coated with a rust preventive paint to a dry film thickness of 150 μm, and dried. The obtained test plate was subjected to an antifouling property test, an abrasive property test, and a skeleton layer measurement test, and the results are shown in the lower part of Table 1.

The test was performed based on the following method.
In Toba Bay, Toba City, Mie Prefecture, the test plate was submerged in the sea at a depth of 30 cm for 45 days, and then a rotor test (15 knots) was performed in the sea at a depth of 30 cm for 45 days.
The cycle was performed for 4 cycles. 1. Antifouling test The appearance of the coating film was observed. <Evaluation Criteria> 5: No deposit is observed on the test plate. 4: Adhesion of thin slime was observed on the test plate. 3: Thick slime adhered to the test plate.

2: Slight attachment of large animals and plants is observed. 1: Large attachment of large animals and plants is observed. 2. Abrasiveness test The film thickness was measured, and the difference from the film thickness before the test was calculated. 3. Skeleton layer measurement test The cross section of the coating film after the rotor test was examined with an electron microscope (SEM-EP).
Elemental analysis was performed by MA), and the thickness of the layer where no metal (anatase-type titanium oxide, cuprous oxide, red iron oxide) distribution was observed on the surface layer of the coating film was measured.

[0018]

[Table 1] Table 1 Example Comparative Example 1 2 3 4 12 Resin solution (A) 100 100 100 100 60 Seawater-insoluble fluororesin solution Note 1) 71 Polyisocyanate Note 2) 8 rosin 20 Anatase type titanium oxide Note 3) 50 75 125 125 Talk 100 6 Cuprous oxide 70 Valve stem 25 20 Xylene 20 42 24 Antifouling 1st cycle 5 5 5 5 2 4 2nd cycle 5 5 5 5 2 3 3rd cycle 5 5 5 5 2 2 4th cycle 5 5 5 5 1 2 Abrasiveness 1st cycle 5 8 11 3 0 7 (μm) 2nd cycle 10 15 18 8 0 12 3rd cycle 17 23 28 12 0 15 4th cycle 23 28 40 18 0 18 Skeleton 1st cycle 3 4 5 3 028 layer (μm) 2nd cycle 2 5 8 2 0 42 3rd cycle 4 4 7 2 0 60 4th cycle 3 5 7 3 0 75 Note 1) Asahi Glass Co., Ltd. Trade name "Lumiflon LF-200", fixed content 60% Note 2) Nippon Polyurethane Industry Co., Ltd. trade name "Coronate HX", solid content 100% Note 3) Ishihara Sangyo Co., Ltd. Name "ST-01", average particle diameter 0.007μm Table 1, is the antifouling coating composition of the present invention Example 1
To 4 had excellent antifouling properties and the like. On the other hand, Comparative Example 1 containing no photocatalyst powder was very poor in antifouling properties. Further, Comparative Example 2, which is a conventional insoluble matrix type antifouling paint, was inferior in long-term antifouling properties and formed a large skeleton layer.

[0019]

Since the underwater antifouling paint of the present invention contains a metal oxide powder having photocatalytic activity, there is no problem in terms of safety and health and environmental preservation, and it is difficult to form a skeleton structure. During the period, the adhesion of underwater organisms can be effectively prevented.

Claims (3)

[Claims] 1. A metal oxide powder having photocatalytic activity,
An underwater antifouling paint composition comprising a binder. 2. A metal oxide powder having photocatalytic activity,
The underwater antifouling coating composition according to claim 1, which is contained in the coating solids at 20 to 85% by weight. 3. The underwater antifouling paint composition according to claim 1, wherein the metal oxide having photocatalytic activity is anatase type titanium oxide.