JPH0665526A - Antifouling coating composition and steel material excellent in anti-smearing property - Google Patents

Abstract

PURPOSE:To obtain a safe, pollution-free antifouling coating composition without using a toxic substance which accumulates in the body by incorporating an oxidoreductase inhibitor as an antifouling ingredient into a coating composition. CONSTITUTION:This position contains an oxidoreductase inhibitor as an antifouling ingredient. The mechanism of fouling prevention in this composition is as follows. The inhibitor inhibits the activity of oxidoreductases resulting from the metabolism of bacteria, especially oxidoreductases in an electron- transfer system, to prevent the growth and attachment of bacteria and, hence, the attachment of larger larval organisms is also prevented. Examples of the inhibitor include amino alcohols, lactones, thiocarbamic acid, and derivatives thereof. These substances are industrially utilized also as drug materials and are commercially available.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling paint for preventing a decrease in efficiency due to biofouling on a ship bottom or an underwater structure, and a steel material coated with the paint and having excellent antifouling performance.

[0002]

2. Description of the Related Art It is generally known that aquatic organisms and marine organisms adhere to and propagate on ship bottoms, intake pipes, etc., leading to deterioration in function and resulting in economic loss. For example, in a ship, it causes a decrease in navigation speed and increases fuel consumption. Further, in the water intake pipe, the liquid transfer efficiency may be lowered or the pipe may be blocked. In order to prevent such biofouling, antifouling paints containing various antifouling active ingredients have been widely used.

Many substances such as organic tin, mercury, arsenic, and cuprous oxide are known as antifouling active ingredients, and these substances prevent the attachment of organisms by killing or repelling them due to their toxicity. To do.

Conventionally, it has been considered that even if these poisons are eluted, there is no problem of pollution due to the dilution / diffusion effect in the ocean. However, contamination by the most commonly used organotin antifouling paint has become a problem in recent years. That is, it has become clear that these poisons are accumulated and concentrated in the living body, causing serious marine pollution. For this reason, at present, antifouling coatings containing toxic substances, especially organic tin, are regulated, and development of effective antifouling paints to replace them is desired.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a safe pollution-free antifouling paint and a steel material excellent in antifouling property without using a substance having a cumulative toxicity.

[0006]

It is generally considered that the attachment of organisms to underwater structures such as a ship bottom is caused by the following process. That is, organic substances such as proteins first adhere, bacteria adhere and propagate there, and larvae of large organisms settle and grow by being attracted to them. The present inventors have made various studies on substances that inhibit bacterial growth based on the finding that preventing bacterial adhesion in these processes can prevent subsequent biological adhesion. As a result, when a substance that inhibits the reaction by the oxidoreductase of bacteria was contained in the paint, it was found that the adhesion of aquatic organisms was prevented and the antifouling performance was excellent, and the present invention was achieved. .

The present invention is summarized by an antifouling paint characterized by containing an oxidoreductase inhibitor as an antifouling component in a paint, and a steel material coated with the paint and having an excellent antifouling property. .

[0008]

The antifouling paint of the present invention is characterized in that an oxidoreductase inhibitor is used as an antifouling component. Thus, there is no antifouling paint that focuses on the inhibition of enzyme reaction, that is, the inhibition of bacterial metabolism. The mechanism of antifouling in this paint is the redox enzyme induced in the metabolic reaction of bacteria,
In particular, by inhibiting the oxidoreductase in the electron transfer system with an inhibitor, the growth and attachment of bacteria are prevented, and as a result, the attachment of larvae of large organisms is also prevented.

The oxidoreductase inhibitor used as the antifouling component in the present invention is a substance known to inhibit oxidoreductase and is not particularly limited as long as it is a substance having no accumulation toxicity. The oxidoreductase here is the metabolism of microorganisms,
In particular, it is involved in the respiratory system that uses oxygen as the final electron acceptor. Examples of the inhibitors that can be used in the present invention include amino alcohols (2-amino-2-methylpropanol etc.), lactones (galactono-1,4-lactone etc.), thiocarbamic acids (diethylthiocarbamate etc.). , Quinoline and isoquinolines (8-hydroxyquinoline, etc.), carboxylic acid amides (semicarbazide, acetamide, etc.), pyrans (arabinose, 2-deoxy-D-glucose, etc.), aliphatic oxyacids and ketone acids (hydroxybutyric acid, Pyruvic acid, etc.), amino acids and their derivatives (leucine, phenylalanine, cysteine, glutathione, etc.), aromatic carboxylic acids (benzoic acid, 3,4-dihydromandelic acid, etc.), mercaptans (mercaptoethanol, etc.), N-ethylmaleimide , Dithiothreitol, allopurino There is Le, and the like. These exemplified substances are industrially used as pharmaceutical raw materials, and commercially available products can be used.

The content of the oxidoreductase inhibitor in the paint is
It is preferably 0.1% by weight or more based on the total solid content of the paint. A content below this level has some antifouling effect, but in order to exert sufficient antifouling performance, it is 0.1% by weight. The upper limit of the content is also not particularly limited, but when it is used as a paint, if the content of the antifouling component exceeds 80% by weight, the film-forming property becomes poor, so 80% by weight or less is preferable. More preferably, it is 60% by weight or less.

The present invention can be applied to any paint normally used for ship bottoms or underwater structures. Specific examples of applicable paints include paints using a general-purpose resin such as a chlorinated rubber resin, an epoxy resin, a silicone resin, a urethane resin, a phenol resin, or a polyester resin as a binder resin. In this paint, extenders such as talc, mica, silica, calcium carbonate, barium sulfate, titanium dioxide, red iron oxide, phthalocyanine blue,
A coloring pigment such as carbon black can be included. Further, other conventional additives such as a dispersant, an oxidation stabilizer, and a thixotropic agent can be added as necessary. Further, a water-soluble resin such as rosin or polyvinyl alcohol resin may be added. When a water-soluble resin is added, it gradually elutes in water, so that the enzyme inhibitor is always exposed on the surface and the antifouling effect is maintained.

In addition, a low toxicity biorepellent other than enzyme inhibitors (stilbene glycosides, flavonoid glycosides, isothiocyanates, etc.) and low toxicity antifouling agents such as cuprous oxide may be used in combination. However, the combined use of highly toxic substances such as organic tin does not meet the purpose of the present invention.

The antifouling paint of the present invention is useful as a ship bottom paint or as a paint for coating marine structures such as intake pipes. In particular, when it is used for coating various steel materials used in seawater, it is possible to prevent biofouling and also prevent corrosion of steel materials due to biofouling. The method for coating the steel material is not particularly limited, and a conventional coating method such as spray coating, electrostatic coating, flow coating, roll coating, brush coating and the like can be used. As the steel material coated with the antifouling paint, a steel material of any shape such as a steel plate, a steel pipe, and a wire can be used. These steel materials are degreased, pickled, sandblasted,
A pretreatment such as a shot blasting treatment or a phosphoric acid-based or chromate-based base treatment may be performed. Further, the antifouling paint of the present invention can be applied on the anticorrosion coating. In that case, it is preferable that the binder resin of the antifouling paint is the same resin system as the anticorrosion coating resin in order to have excellent adhesion to the anticorrosion coating resin.

[0014]

EXAMPLES The present invention will be described below with reference to examples.

First, a paint having the composition shown in Table 1 was prepared. Various kinds of antifouling agents were added thereto to prepare coating compositions having the compositions shown in Table 2. The paint has a viscosity of 2000 to 5000 cps at room temperature by adding solvents such as MEK and toluene as needed.
I adjusted it to be. The enzyme inhibitors added as antifouling agents are commercially available 8-hydroxyquinoline and semicarbazide.

On the other hand, after degreasing a hot rolled steel sheet having a thickness of 300 × 300 × 3.2 mm, sandblasting was performed on the entire surface to adjust the surface to Sa2.5 or more.

The blast steel plate was airless spray coated with the trial paint. Coating thickness is 300 ± 50 μm as dry film thickness
I adjusted it to be. The coating was performed on both sides, and the edges were coated with a brush.

The sample thus obtained was taken from the coast of the inner bay.
An actual seawater immersion test was carried out by mounting the raft at a position 20 m away. The upper part of the sample was suspended for vertical immersion, and the upper end of the sample was adjusted to be 10 cm below the sea level. The antifouling performance (biological adhesion state) of this sample was visually observed after 6 months and 1 year.

Separately from this, this sample was
Immerse it in a 500 × 400 water tank, discharge 20 medaka, and
Toxicity was evaluated by the survival rate after day.

The results of the antifouling performance and toxicity test are shown in Table 2. As is clear from the test results of Test Nos. 1 to 13 which are antifouling paints of the present invention, addition of an enzyme inhibitor can impart nontoxic and excellent antifouling performance. On the other hand, as is clear from the results of Comparative Examples Test Nos. 14 to 17, organotin compounds show excellent antifouling performance, but are highly toxic and pose a problem in terms of water pollution. In addition, test No. with no enzyme inhibitor added
In 17, the biofouling is remarkable.

Further, other oxidoreductase inhibitors (2-
It was confirmed that the addition of amino-2-methylpropanol, mercaptoethanol, pyruvic acid, dithiothreitol) had the same effect as 8-hydroxyquinoline and semicarbazide.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

As described above, the antifouling coating composition of the present invention containing an oxidoreductase inhibitor can impart excellent antifouling performance and is nontoxic, so that it can cause water pollution. As a safe antifouling paint, it can be used for marine structures such as ship bottoms and seawater intake pipes.

Claims (2)

[Claims] 1. An antifouling paint, wherein the paint contains an oxidoreductase inhibitor as an antifouling component. 2. Covered with the antifouling paint according to claim 1,
Steel material with excellent stain resistance.