JP2005281398A - Coating composition for preventing attachment of marine organism, and method for preventing attachment of marine organism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating composition for preventing the attachment of marine organisms, preventing the attachment of the ocean organisms to an ocean structure or a ship by applying electric characteristics of garnet causing no marine pollution, and synergistic action of anatase-type titanium dioxide. <P>SOLUTION: The coating composition for preventing the attachment of the marine organisms is obtained by compounding a mixed fine powder of a mineral-fired oxide containing the garnet and rare earth elements, and the anatase-type titanium dioxide with a synthetic resin compound. When the composition is formed into a coated film, the coated film component is not eluted even when soaked in sea for a long period. The attachment of the ocean organisms is prevented by heightening an alkali ion concentration of water at the surface of the film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a marine organism adhesion preventing coating composition and a marine organism adhesion preventing method capable of continuously preventing adhesion of marine organisms such as barnacles and mussels to an underwater marine structure or the bottom of a ship.

Bacteria, which are initially attached as marine organisms, are found on the surface of seawater such as marine structures and submerged facilities immersed in seawater for a long period of time, power plant cooling channels, ship bottoms, stationary nets, and aquaculture nets. And barnacles, mussels, bryophytes, sea squirts, etc. are attached. In particular, marine organism shells and the like adhered to the bottom of the ship, leading to increased resistance to running water at the bottom of the ship, increasing fuel consumption, or reducing rust prevention performance.
In addition, a large amount of marine organism shellfish may adhere to the surface of the cooling waterway structure of the power plant, reducing the cross-sectional area of the cooling waterway, increasing the flow resistance, and blocking the cooling waterway itself. It was.
Furthermore, marine organisms attached to various types of nets may cause an increase in net weight, damage, damage to fish, and the like.
Therefore, it is necessary to periodically remove the attached marine organisms. For example, a ship or the like is moored and submerged for removal work, or the operation is stopped and removed at a power plant or the like. It was necessary to carry out the process, and it took a lot of time and cost.

  Conventionally, organotin compounds have been kneaded into paints to achieve high antifouling effects as a countermeasure to prevent the adhesion of marine organisms, but fish malformation has been a frequent problem. Although the use of organotin compounds has been voluntary, painting on ships was prohibited in 2003 by the International Maritime Organization (IMO) headquarters.

As a non-tin antifouling paint, knead an elution component such as sodium chloride or calcium chloride into the paint component, or knead a basic compound such as calcium hydroxide or barium hydroxide. Proposals have been made to prevent adhesion of marine organisms by means of elution into seawater (for example, Patent Documents 1 to 3).
For example, in Patent Document 1, sodium chloride, potassium chloride, magnesium sulfate, and the like are impregnated into a coating film component, and these elution components gradually dissolve out from the coating film component, and the elution ion concentration is increased from seawater to prevent the attachment of marine organisms. Proposals to prevent are disclosed.
In Patent Document 2, a basic substance such as calcium hydroxide, barium hydroxide, or magnesium hydroxide is supported in the coating film, and these hydroxides are gradually eluted from the film, and the alkalinity of the water on the coating surface is controlled. A proposal to prevent the attachment of marine organisms by increasing is disclosed.
In Patent Document 3, Portland cement, blast furnace cement, calcium hydroxide and the like are impregnated into a synthetic resin as a powdery basic compound, and the hull surface is made alkaline by gradually eluting while suppressing rapid elution of alkali components. Proposals have been disclosed to prevent rusting and prevent marine organisms from sticking.
In these Patent Documents 1 to 3, the components supported or impregnated in the coating are gradually dissolved out of the coating to increase the concentration of components in the vicinity of the coating, or by making the water on the coating surface alkaline, This is a proposal to prevent the attachment of organisms.
Patent Document 4 is a self-degrading paint in which anatase-type titanium dioxide is contained in a biodegradable polymer. The coating gradually peels and dissolves in the sea, and a new surface coating is always produced, thereby preventing soiling. It is a method to create sex.
Further, Patent Document 5 has been proposed by the present inventors, and by using together a garnet of a natural silicate mineral and a calcined mineral oxide containing a rare earth element, the electrical properties of the garnet are enhanced, The effect of preventing the attachment of marine organisms is achieved by making the water in the vicinity alkaline.
Japanese Patent No. 2926447 Japanese Patent Laid-Open No. 9-255897 JP 10-152629 A JP 2001-114616 A JP 2003-55608 A

However, in the method of eluting the component supported from the coating as in Patent Documents 1 to 3, although the coating component is actively eluted at the initial stage when the coating is immersed in seawater, the immersion is continued for a long time. The amount of elution of the elution component is extremely small, the antifouling effect is lowered, and finally the antifouling effect is lost when the elution component in the coating disappears.
Moreover, in the proposal which aimed at the antifouling effect by the biodegradation action and photocatalyst action containing titanium dioxide by the self-decomposition method like the above-mentioned patent documents 4, the antifouling object is an environment of several meters in the sea like a ship bottom The amount of solar energy to reach was small, the photocatalytic action was very low, and the antifouling effect was very low.
Furthermore, in the said patent document 5, the higher adhesion prevention effect was calculated | required.

Therefore, as a result of repeated studies for increasing the alkali ion concentration on the surface of the coating film in seawater, the present inventors have used anatase-type titanium dioxide, resulting in an extremely high amount of negative ion generation on the surface of the coating film. It was confirmed that the alkali ion concentration on the surface of the coating was remarkably improved, the marine organism adhesion preventing effect was remarkably enhanced and continued for a long period of time, and the present invention was completed.
The present invention has been proposed in view of the above, characterized in that a mixed fine powder of a natural silicate mineral garnet and a calcined mineral oxide containing a rare earth element and anatase titanium dioxide are kneaded into a synthetic resin compound. The present invention relates to a marine organism adhesion preventing coating composition.

  Further, the present invention provides a synthetic resin compound comprising 3-50 parts by weight of a mixed fine powder of garnet, a natural silicate mineral, and a calcined mineral oxide containing a rare earth element, and 1-40 parts by weight of anatase titanium dioxide. The present invention also proposes a marine organism adhesion prevention method characterized in that a coating film is formed by applying a marine organism adhesion prevention coating composition kneaded in 100 parts by weight.

The marine organism adhesion prevention coating composition of the present invention is applied to marine structures and ship bottoms where seawater comes into contact on a daily basis, and applies the electrical properties of garnet and the water modification effect of anatase titanium dioxide. Thus, there is no component that dissolves into the sea from the coating composition, there is no marine contamination, and the effect of preventing the attachment of marine organisms semipermanently can be continued as long as the coating is not damaged. That is, a semi-permanent marine organism adhesion preventing effect can be imparted to marine structures, undersea facilities, power plant cooling water channels, ship bottoms, and the like.
In addition, in order to improve the electrical properties of garnet, it is used in combination with a calcined mineral oxide containing rare earth elements, and further, by synergistic action with anatase type titanium dioxide, the paint composition is applied to undersea structures, ship bottoms, etc. By forming a coating film, it is possible to prevent the attachment of marine organisms semi-permanently, and the time, labor, and cost for removing the deposit can be eliminated or greatly reduced.

  In addition, the marine organism adhesion prevention method of the present invention only needs to form a film by applying a marine organism adhesion prevention coating composition having a specific composition to an adherend, and substantially requires subsequent maintenance. do not do. Therefore, for example, when the adherend is a ship, the fuel amount of the ship can be significantly reduced. For example, when the adherend is a cooling water channel of a power plant, it is not necessary to stop and stop the operation of the power plant. Is extremely large.

  20 parts by weight of a mixed fine powder composed of 97 to 80% by weight of a calcined mineral containing 3 to 20% by weight of a rare earth element with respect to 100 parts by weight of a synthetic resin compound (solid content 35%), and 5 to 20% by weight of anatase type titanium dioxide The coating composition kneaded in part is most suitable and has a high effect of preventing marine organism adhesion.

  The negative ion generation and alkali ion generation in the marine organism adhesion prevention coating composition of the present invention will be described.

The natural silicate mineral garnet used in the present invention has the same electrical characteristics as tourmaline [tourmaline: NaFe ₃ Al ₆ (BO ₃ ) ₃ Si ₆ O ₁₈ (OH ₉ F) ₄ ]. This is as disclosed in Japanese Patent No. 3286298 and Japanese Patent No. 3286307, which have conducted detailed research on characteristics. Further, tourmaline is disclosed in Solid Physics Vol. 24, No. 12 (1989).

First, the electric characteristics of tourmaline are special polar crystals called permanent electrodes, and the pulverized fine particles are independent polar crystals, and when they come into contact with water, water (H ₂ O) Although it is dissociated into hydrogen ions (H ⁺ ) and hydroxide ions (OH ⁻ ), oxygen gas is not generated even though hydrogen gas is generated, and it is known that the concentration of alkali ions (HO ⁻ ) in water increases. It has been.

Next, the electrical characteristics of the garnet will be described. The natural silicate mineral garnet is a nesosilicate composed mainly of divalent iron oxide, and its composition is Fe ₃ Al ₂ (SiO ₄ ) ₃ .
As a result of conducting further detailed research on the electrical characteristics of garnet, the present inventors have obtained the following knowledge. This is disclosed in Patent Document 5.
Armandite garnet was used as the garnet of natural silicate mineral. This almandite garnet is a natural natural round-cornered sand having a particle size of about 250 to 500 μm. The composition is summarized as follows: SiO ₂ : 37.6%, Al ₂ O ₃ : 20.9%, FeO: 31.3%, CaO: 1.64%, MgO: 6.21%, MnO: 1.18 %, K ₂ O: 0.01%, ZnO: 0.02, Y ₂ O ₃ : 0.05%. Since this garnet is pulverized into fine particles having a particle size of about 75 to 100 μm and put into a column, and this is made to flow and flow, when it comes into contact with water, the pH value of raw water (purified water) is initially 6.62. After 2 minutes it was 8.54, and after 5 minutes it was 9.61. The ¹⁷ O-NMR spectrum half-width value obtained by nuclear magnetic resonance (NMR) of water in contact with the garnet fine particles was 71.0 Hz, which was confirmed to be smaller than 117.5 Hz of the raw water (purified water).
Further, the cation concentrations of alkaline metals such as Ca ⁺⁺ ions, K ⁺ ions, and Mg ⁺⁺ ions as garnet components were analyzed. As a result, Mg ⁺⁺ = 0.5 mg / l, Ca ⁺⁺ = 0.5 mg / l, K ⁺ <0.1 mg / l, Al ⁺⁺⁺ <0.5 mg / l, Si ⁺⁺⁺⁺ = 0.5 mg / l, Fe ⁺⁺ <0.05 mg / l. Since these total cation molar concentrations are extremely small and are not concentrations that cause rapid pH change, the water in contact with the garnet fine particles immediately changes pH and becomes alkaline, and the 17O-NMR cluster The phenomenon that the full width at half maximum (Hz) is reduced is a novel finding that garnet, a natural silicate mineral, is weak but has electrical characteristics similar to those of tourmaline.
In addition, by mixing a fine powder of natural silicate mineral with a fine powder of natural silicate mineral and a fired mineral containing rare earth elements together with a synthetic resin compound, the amount of negative ions generated on the coating surface can It is also disclosed that the amount of alkali ions on the surface of the coating increases as compared with the case of.

In the marine organism adhesion prevention coating composition of the present invention, based on the application of the electrical characteristics of the garnet described above, even if the garnet kneaded in the coating is in seawater, it is semipermanently near the coating as long as it is present in the coating. from water OH ^- continue to generate, it is possible to prevent adhesion of marine organisms continues to maintain the alkalinity.

Further, the present invention improves the electrical properties of garnet, and further enhances the surface activity due to hydroxyl radical (.OH), which is an active species of anatase-type titanium dioxide, even at the bottom of a ship with a low solar radiation dose of several meters in the sea. It has been found that the generation rate of alkali ions, which are negative ions, is increased and the generation amount is increased by the excitation action of calcined minerals containing elements.
That is, the present invention is based on the synergistic effect of the garnet's electrical properties, surface activity by hydroxyl radicals of anatase-type titanium dioxide and excitation action of calcined mineral oxides containing rare earth elements. As long as it exists in the seawater even if it exists in the seawater, OH ^- can be generated semipermanently from the water in the vicinity of the seawater, maintaining alkalinity and preventing the adhesion of marine organisms. It came.

First, the alkalinization of water (H ₂ O) by the electrical characteristics of the garnet of the present invention will be described.
Water molecules (H ₂ O) are always in an equilibrium state as shown in the following formula (1).
H ₂ O ⇔ OH ⁻ + H ⁺ (1)
When the water molecules come into contact with the garnet, the equilibrium state is broken, and a part of the hydrogen ions (H ⁺ ) becomes hydrogen gas and leaves the water. As a result, the concentration of hydroxyl negative ions [OH ⁻ ] is increased and alkalinized.

Next, the surface activity of the hydroxyl radical of anatase-type titanium dioxide (TiO ₂ ) will be described. The anatase-type reaction mechanism is not necessarily clear, but is generally considered as follows.
Anatase titanium dioxide (TiO ₂ ) absorbs light waves, and electrons (e ⁻ ) and holes (h ⁺ ) are generated inside the anatase titanium dioxide.
TiO ₂ + on (light) → e ⁻ + h ⁺ (2)
H ⁺ (hole) in the formula (2) reacts with water to generate a hydroxyl radical (.OH). It shows in Formula (3).
h ⁺ + H ₂ O → OH ⁻ (· OH) + H ⁺ (3)

  In the present invention, in order to further enhance the electrical properties of garnet and the surface activity of hydroxyl radicals of anatase titanium dioxide, the excitation action of calcined minerals containing rare earth elements is applied to reduce the generation rate and concentration of alkali ions in water. I am trying to improve it.

  The average particle size of the mixed fine powder of the garnet fine powder used in the present invention and the calcined mineral oxide containing rare earth elements is preferably about 5 μm, and the main components of the mineral oxide containing rare earth elements are lanthanum, cerium, neodymium, silicon. Further, rare earth elements such as zirconium and yttrium are contained in an oxide state.

The anatase-type titanium dioxide used in the present invention is devised with respect to the addition method and the addition amount in order to exert the surface activity effect of the hydroxyl radical.
Anatase-type titanium dioxide alone does not give a measured value of the amount of negative ions generated, but generates hydroxyl radical negative ions by the excitation action of a calcined mineral oxide containing rare earth elements.

Examples of the synthetic resin compound used in the present invention include silicone resin, silicone rubber latex, natural rubber latex, acrylic resin, acrylic rust preventive resin, epoxy resin, epoxy vinyl acetate resin, alkyd resin, fluorine resin, and the like. The anticorrosive paint can be used. Preferred examples of such various synthetic resin compounds are shown.
3-50 wt. Of mixed fine powder consisting of 3-50 wt.% Of garnet of natural silicate mineral and 97-50 wt.% Of calcined mineral containing rare earth element to 100 wt parts of acrylic copolymer resin emulsion (solid content 35%). Part and 1 to 40 parts by weight of anatase-type titanium dioxide were kneaded to obtain a marine organism adhesion preventing coating composition.

  The marine organism adhesion-preventing coating composition of the present invention comprises a total of four components: garnet, a natural silicate mineral, calcined mineral oxide containing rare earth elements, anatase-type titanium dioxide, and synthetic resin compound. It is preferable to mix the components in a specific range. That is, a composition in which 3 to 50 parts by weight of a mixed fine powder of garnet and a calcined mineral oxide containing a rare earth element and 1 to 40 parts by weight of anatase-type titanium dioxide are kneaded into 100 parts by weight of a synthetic resin compound is desirable.

  More desirably, 20 parts by weight of a mixed fine powder composed of 3 to 20% by weight of garnet and 97 to 80% by weight of a calcined mineral containing a rare earth element with respect to 100 parts by weight of a synthetic resin compound (solid content 35%), anatase type A coating composition in which 5 to 20 parts by weight of titanium dioxide is kneaded is most suitable, the amount of negative ions generated is large, and the effect of preventing adhesion of marine organisms is high.

As described above, the mixed fine powder of garnet and a calcined mineral oxide containing a rare earth element is preferably 3 to 50 parts by weight (relative to 100 parts by weight of the synthetic resin compound). If the amount of garnet in the mixed fine powder is too large, the amount of calcined mineral containing rare earth elements decreases, and the amount of mixed fine powder added must be increased. However, an increase in the amount of the mixed fine powder is not preferable because it leads to a decrease in coating strength.
As described above, the anatase-type titanium dioxide is preferably 1 to 40 parts by weight (relative to 100 parts by weight of the synthetic resin compound), more preferably 5 to 20 parts by weight. If the amount of the anatase-type titanium dioxide is too small or too large, the amount of negative ions generated is reduced and the effect of preventing the adhesion of marine organisms is reduced.

  Further, as the adherend to which the marine organism adhesion preventing coating composition of the present invention is applied, it is assumed that marine organisms and marine facilities that are immersed in seawater and to which marine organisms adhere are attached. Examples of marine organisms to be prevented from adhering include various aquatic organisms that live in seawater, including barnacles, mussels, bryozoans, scallops, bacteria, and algae.

Mixed fine powder (average particle size 5 μm) consisting of 100 parts by weight (solid content 35%) as synthetic resin compound, 100 parts by weight (solid content 35%), 5% by weight alumandite garnet as garnet, and 95% by weight calcined mineral containing rare earth elements 20 parts by weight and 10 parts by weight of anatase-type titanium dioxide were kneaded to obtain a marine organism adhesion preventing coating composition.
This marine organism adhesion prevention coating composition was applied with a brush to a steel material (300 m / m × 300 m / m) which had been pretreated with a rust-prevention coating in advance to form a dry film of 0.3 to 0.5 m / m.
The coated steel material thus obtained was immersed in 500 ml of purified water (Japanese Pharmacopoeia) and stirred in a circulating manner. The initial pH was 6.67, but the pH of water after 15 minutes was 9. It became 20.
The amount of negative ions generated in the coated steel was 3500 / cm ³ .
Then, this coated steel material was immersed in a depth of 2 m in the sea, held for 6 months, and the state of adhesion of marine organisms was tested.
As a result, no marine organisms were found on the surface of the painted steel. Subsequent immersion in the sea continued for one year, but no attachment of marine organisms was confirmed. Moreover, when the weight of this coated steel was measured, there was no increase or decrease, and no iron rust was generated.
Moreover, when the coated steel material immersed in the sea for 1 year was immersed in purified water (pH is 6.67), the pH of water after 15 minutes was 9.60. Therefore, it was confirmed that the alkali ion generation effect is continuously exhibited even after one year.

Comparative example

  For comparison, a steel material prepared in exactly the same manner except that the marine organism adhesion preventing coating composition was not applied was immersed in the sea in the same manner as the coating film of Example 1. As a result, numerous marine organisms (mainly barnacles) The adhesion of was confirmed.

Natural silicate mineral containing 100 parts by weight of non-tar epoxy resin (solid content 35%) as synthetic resin compound, 5% by weight of alumandite garnet as garnet, and rare earth elements such as lanthanum, cerium, neodymium, silicon, zirconium and yttrium 10 parts by weight of a mixed fine powder (average particle size 5 μm) composed of 95% by weight of the above baked oxide and 5 parts by weight of anatase-type titanium dioxide were kneaded to prepare a marine organism adhesion preventing coating composition.
This marine organism adhesion preventing coating composition was applied to an iron plate primed with a rust preventing coating in the same manner as in Example 1 to form a coating.
The coated iron plate thus obtained was made in the same manner as the test method described in Example 1 above.
The pH of the water after dipping the coated iron plate in purified water for 15 minutes was 9.80.
The amount of negative ions generated in the coated iron plate was 3050 negative ions / cm ³ .
As a result of immersing the coated iron plate in the sea for one year, no adhesion of marine organisms was confirmed on the coated iron plate, no increase or decrease in weight, and no rust was observed.

  A semi-permanent marine organism adhesion prevention effect can be imparted to offshore structures, underwater equipment, power plant cooling channels, ship bottoms, and the like.

Claims (3)

  A marine organism adhesion-preventing coating composition comprising a synthetic resin compound and a mixed fine powder of a natural silicate mineral garnet and a calcined mineral oxide containing a rare earth element and anatase-type titanium dioxide.   A mixture of 3 to 50 parts by weight of fine powder of natural silicate mineral garnet and calcined mineral oxide containing rare earth elements and 1 to 40 parts by weight of anatase type titanium dioxide are kneaded into 100 parts by weight of a synthetic resin compound. The marine organism adhesion preventing coating composition according to claim 1.   3-50 parts by weight of a mixed fine powder of natural silicate mineral garnet and a rare earth element-containing calcined mineral oxide and 1-40 parts by weight of anatase titanium dioxide are kneaded into an adherend in 100 parts by weight of a synthetic resin compound. A marine organism adhesion prevention method characterized in that a film is formed by applying a marine organism adhesion prevention coating composition.