JPH0768467B2 - Antifouling paint - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an antifouling paint for preventing adhesion of aquatic organisms to underwater structures, ship bottoms and the like.

[Technical Background of the Invention and its Problems] Underwater structures, articles that are used for a long time in water, such as ship bottoms, not only have aquatic organisms attached and propagate during use, impairing their appearance, but also adversely affecting their functions. May be given.

In the case of the bottom of the ship, the adhesion of aquatic organisms increases the surface roughness of the entire ship, which reduces the ship speed and increases fuel consumption. As a result, the repair period at the dock will become longer and the operating efficiency will drop significantly. In addition, the propagation of bacteria causes enormous damage such as decomposition of the underwater structure and deterioration of its physical properties, resulting in a marked decrease in life.

Conventionally, as antifouling agents used to avoid such damage, organic chlorine compounds, cuprous oxide, organic tin compounds and the like are known.

A physiologically active substance containing a heavy metal such as an organic tin compound or cuprous oxide has a particularly excellent antifouling effect and is considered to be an essential component for an underwater structure or a paint for a ship bottom. For example, U.S. Pat. No. 3,167,473 describes an antifouling agent using an organotin compound, which is called "polymer type". This antifouling treatment agent
Having an organotin-containing group in the side chain of the copolymer, it is hydrolyzed in slightly alkaline seawater to release the organotin compound, and exhibits an antifouling effect, and at the same time, the hydrolyzed copolymer itself is also water-soluble. Since it is transformed into and dissolves in seawater, an active surface can always be maintained without leaving a resin residue layer.
It is also described that the combined use of cuprous oxide is preferable in order to improve the antifouling effect of this paint. In addition,
-231771 publication, for the purpose of promoting the elution of physiologically active substances such as contained organotin compounds and cuprous oxide, as a part of the monomer of the organotin-containing copolymer used in combination therewith, hydrolyzed. Methods using degradable silyl (meth) acrylates are described. However, in the antifouling treatment agent in which these copper compounds such as cuprous oxide are used in combination, there is a problem that the polymer gels within a few days. Therefore, when long-term storage is required, the organotin-containing copolymer and the copper compound must be separately packaged and stored. Such a two-component paint is difficult to mix in a large amount and is not practical. In addition, when the final composition was not mixed uniformly, fouling could occur early in the portion where the concentration of the copper compound was low.

Therefore, various stabilizers have been proposed (US Pat. No. 4,191,579), but the organotin compound is highly irritating and causes inflammation when it comes into contact with the skin. However, there were serious problems such as marine pollution due to outflow into seawater, occurrence of malformed fish, and accumulation in human body due to ecological concentration.

For this reason, Japanese Patent Publication No. 60-500452 discloses a treating agent having an antifouling effect without using an organotin-containing copolymer. This antifouling treatment agent is composed of a poison and a self-polishing type polymer, and the monomer of the polymer is a hydrolyzable silyl (meta) such as tris (4-methyl-2-pentoxy) silyl acrylate. Acrylate is mentioned.

However, this self-polishing polymer has a problem that it only functions as a delivery system for poisonous substances, does not have antifouling performance by itself, and it is difficult to exhibit self-polishing properties in a stationary state. When cuprous oxide or the like is used as a poisonous component, the storage stability is poor,
There was also the problem of gelation within a few days. Moreover, in this antifouling agent, the known stabilizers effective in organotin-containing copolymers, such as EDTA, antioxidants, ethyl silicate, ethyl orthoformate, and lead compounds, had no effect.

[Object of the Invention] The present invention provides an antifouling paint which does not contain an organotin compound and an organotin-containing copolymer, does not adversely affect the marine ecosystem, and has excellent static antifouling properties. The purpose is to do.

[Structure of the Invention] The present inventors paid attention to the self-polishing property of the antifouling paint,
The present invention has been accomplished by finding a coating composition having excellent antifouling property and good storage stability without using an organotin compound and an organotin-containing copolymer.

That is, the antifouling paint of the present invention has the general formula (A) (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² , R ³ , and R ⁴ are each a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, and a phenyl group. And at least one of them represents a monovalent hydrocarbon group having 4 or more carbon atoms.) And at least one unsaturated triorganosilyl monomer represented by the formula (1), and a (meth) acrylic or vinyl compound. A copolymer obtained by polymerizing at least one kind of organic monomer, (B) copper powder, copper alloy powder and / or copper compound, and (C) fine powder of polymethylsilsesquioxane. Is characterized by.

The copolymer of the component (A) used in the present invention is a characteristic component in the present invention, and shows appropriate hydrolyzability by selecting an organic group bonded to a silicon atom of a triorganosilyl group, It exhibits controlled dissolution characteristics in water because it gradually hydrolyzes in water to increase its hydrophilicity. Such a copolymer is obtained by polymerizing one or more unsaturated triorgansilyl monomers and one or more organic monomers to a polymerization degree of about 50 to 10,000. To be

The composition ratio of the unsaturated triorganosilyl monomer and the organic monomer is not particularly limited, but the amount of the unsaturated triorganosilyl monomer is preferably 10 to 95% by weight, more preferably 20 to 70% by weight. Is the range. If the amount of the unsaturated triorganosilyl monomer is less than 10% by weight, the required hydrolysis rate cannot be obtained and sufficient antifouling property is not exhibited. On the other hand, if it exceeds 95% by weight, the physical properties of the coating film will be poor and the hydrolysis rate will be excessive, so that it will dissolve in a short time and the antifouling power will not continue.

In the unsaturated triorganosilyl monomer, which is one of the starting materials for the copolymer, R ¹ is a hydrogen atom or a methyl group, and R ² , R ³ , and R ⁴ are each independently 1 to 18 carbon atoms. It is a valent hydrocarbon group and is selected from linear or branched alkyl groups, cycloalkyl groups and phenyl groups. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, a myristyl group, and a stearyl group, and the cycloalkyl group includes a cyclopentyl group,
A cyclohexyl group and the like are exemplified. At least one of R ² , R ³ and R ⁴ has a carbon number of 4 in order to have moderate hydrolyzability and thereby to control the sustained solubility of the paint in water.
It must be more than that.

As such an unsaturated triorganosilyl monomer,
Dimethyl butyl silyl acrylate, dimethyl hexyl silyl acrylate, dimethyl octyl silyl acrylate, dimethyl decyl silyl acrylate, dimethyl dodecyl silyl acrylate, dimethyl cyclohexyl silyl acrylate, dimethyl phenyl silyl acrylate, methyl dibutyl silyl acrylate, ethyl dibutyl silyl acrylate, dibutyl hexyl silyl acrylate , Dibutylphenylsilyl acrylate, tributylsilyl acrylate, triphenylsilyl acrylate, and the like; and corresponding methacrylates. Of these, R ² , R ³ , R ⁴ such as dimethylhexylsilyl (meth) acrylate and dimethyldecylsilyl (meth) acrylate are preferred because of their slow hydrolysis rate, ease of synthesis, and good film-forming property. Of these, two having a methyl group and the remainder having a long-chain alkyl group having 6 or more carbon atoms are excellent, but have a controlled hydrolysis rate in water,
Tributylsilyl (meth) acrylate is preferable in order to obtain appropriate moderate solubility.

The organic monomer, which is the other starting material of the copolymer, is selected from (meth) acrylic compounds and vinyl compounds. Examples of the (meth) acrylic compound include methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate (the above alkyl groups may be linear or branched), 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate. , Dimethylaminoethyl acrylate, acrylamide, acrylonitrile and the like; and methacrylic compounds corresponding to these are exemplified, and as vinyl compounds, vinyl acetate, vinyl chloride, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether,
Examples include vinyl isobutyl ether and vinylpyrrolidone.

The polymerization is carried out, for example, by mixing the unsaturated triorganosilyl monomer and the organic monomer in the presence of an organic solvent and using a polymerization initiator.

The organic solvent is for controlling the polymerization and preventing the formation of gel during the reaction, and is a hydrocarbon solvent such as benzene, toluene and xylene, an ester solvent such as ethyl acetate and butyl acetate; methanol and ethanol. Examples thereof include alcohol solvents such as; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; and aprotic polar solvents such as dimethylformamide and dimethyl sulfoxide.

The amount of organic solvent is 20 per 100 parts by weight of the total amount of monomers.
〜1000 parts by weight is preferable, and more preferably 50 to 500 parts by weight. If the amount of the organic solvent is less than 20 parts by weight, it becomes difficult to control the reaction, and if it exceeds 1000 parts by weight, a concentration step is required when forming the antifouling paint. Further, in order to avoid hydrolysis during polymerization and storage, these organic solvents should be used after removing water.

As the polymerization initiator, benzoyl peroxide, t-
Examples thereof include organic peroxides such as butyl perbenzoate, methyl ethyl ketone peroxide, cumene hydroperoxide, and azo compounds such as azobisisobutyronitrile.

The amount of the polymerization initiator is 100 parts by weight of the total amount of the monomers.
0.01 to 10 parts by weight is common.

The polymerization conditions are not particularly limited, but it is preferable to carry out in a nitrogen stream, and generally, the temperature is 60 to 120 ° C when the polymerization initiator is an organic peroxide, and 45 to 100 ° C when the polymerization initiator is an azo compound. Be seen.

The component (B) component copper powder, copper alloy powder, and copper compound used in the present invention have physiological activity against organisms attached to underwater structures, ship bottoms, etc., and are for preventing the attachment and growth. Examples of the copper alloy powder include copper / nickel alloy powder; examples of the copper compound include cuprous oxide, cuprous thiocyanate, copper oxine, and copper naphthenate. Although the amount of the component (B) is not particularly limited, it is preferably in the range of 10 to 500 parts by weight based on 100 parts by weight of the component (A) under general use conditions. When the amount of the component (B) is less than 10 parts by weight, the antifouling property is poor in a stationary state, and when it exceeds 500 parts by weight, it becomes difficult to mix it in the system.

The polymethylsilsesquioxane fine powder of the component (C) used in the present invention is stored for preventing the component (A) from gelling when the components (A) and (B) are mixed. It is a stabilizer. Such polymethylsilsesquioxane fine powder can be obtained, for example, by hydrolyzing and condensing methyltrialkoxysilane or a partial hydrolysis-condensation product thereof in a solution of ammonia or amines.

The average particle size of the component (C) is preferably 0.1 to 100 μm. If the average particle size is less than 0.1 μm, it is difficult to manufacture, and the amount that can be filled is limited, and if it exceeds 100 μm, it is difficult to obtain the necessary stabilizing effect. In addition, this polymethylsilsesquioxane fine powder has a low specific gravity after high filling compared to fine powder silica of the same shape, does not increase the viscosity of the system, and is highly fluid.

Although the amount of the component (C) is not particularly limited, the component (A) 10
The range of 0.5 to 300 parts by weight with respect to 0 parts by weight is preferable. 0.5
If it is less than 300 parts by weight, the stabilizing effect will be poor, and if it exceeds 300 parts by weight, it will be difficult to compound it in the system.

The antifouling coating composition of the present invention can be obtained by adding a pigment, an organic solvent, a thixotropic agent, etc. to the above-mentioned components (A), (B) and (C), if necessary. In addition to the copper-based antifouling agent as the component (B), a dithiocarbamate compound such as dimethyldithiocarbamate zinc, ethylenebisdithiocarbamate zinc, ethylenebisdithiocarbamate manganese, or a thiuram compound such as tetrathiuram disulfide is used as an antifouling agent. It is also possible to use them together as agents. Since the target of the antifouling treatment is various such as underwater structures and ship bottoms, the blending ratio is not particularly limited, but the blending amount of the copolymer is preferably in the range of 1 to 60% by weight. If the content of the copolymer is less than 1% by weight, it is difficult to form a coating film, and if it exceeds 60% by weight, the apparent viscosity increases and the workability deteriorates.

As pigments, red iron oxide, titanium white, talc, silica,
Examples include seawater inactive pigments such as calcium carbonate and barium sulfate, and seawater-reactive pigments such as zinc oxide and calcium oxide. One kind or a combination of two or more kinds may be used.

As the organic solvent, the same one as used in the polymerization step for obtaining the above-mentioned copolymer is used.

Examples of the thixotropic agent include bentonite, polyethylene oxide and amide compounds.

[Effects of the Invention] The antifouling coating composition obtained by the present invention has excellent storage stability and always maintains a new coating film surface due to the self-polishing property due to hydrolysis of the copolymer, and also allows copper ions to be gradually added to seawater. As it elutes, it exhibits an excellent antifouling effect for a long period of time.

The antifouling paint of the present invention is effective in preventing contamination due to the attachment of aquatic organisms such as underwater structures and ship bottoms.

[Examples] Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. In the following examples, parts are parts by weight.

(Synthesis of Copolymer) 300 parts of xylene was charged into a reaction vessel equipped with a cooler, a stirrer and a thermometer, and 120 parts of dimethylhexylsilyl methacrylate, 180 parts of methyl methacrylate and 2 parts of azobisisobutyronitrile were charged into the reaction container. Was added, and the mixture was heated and stirred at 80 ° C. for 8 hours to carry out polymerization. After cooling to room temperature,
66 parts of ethyl acetate was added to obtain a pale yellow transparent copolymer solution V-1. The viscosity of V-1 at 25 ° C. was 480 cP, and the solid content concentration was 44.8%.

Further, in the same manner as V-1 except that the addition of the organic solvent after the polymerization is not performed, the pale yellow transparent copolymer solution V-2 to the organic solvent, the monomer and the reaction initiator shown in Table 1 are used. V-7
Got

The viscosity and solid concentration of the obtained copolymer solution are shown in Table 1. The numbers showing the blending amounts in the table represent parts. (same as below.) (Synthesis of polymethylsilsesquioxane) A four-necked flask equipped with a thermometer, a reflux condenser and a stirrer was charged with an aqueous ammonia solution having the temperature and the amount shown in Table 2, and methyltrimethoxysilane was added to the aqueous ammonia solution. 200 parts was gradually added dropwise with stirring over about 40 minutes. The reaction temperature starts from 10 ℃, and at the end of dropping,
Reached 30 ° C. Then, it was heated with a mantle heater to reflux at 84 ° C., and stirring was continued at this temperature for about 1 hour. After cooling, the product precipitated in the flask was collected, washed with water and dried to obtain powdery polymethylsilsesoxane S-1 to S-3 having excellent free-flowing properties shown in Table 2. Was given.

Examples 1 to 10 and Comparative Examples 1 to 8 Copolymer solutions V-1 to V-obtained as described above
7. Polymethylsilsesquioxane fine powder S-1 to S-
With 3 and cuprous oxide or cuprous thiocyanide,
The antifouling paint according to the present invention was prepared by the formulation shown in Table 3.

For comparison with the present invention, as Comparative Examples 1 to 4, antifouling paints containing no polymethylsilsesquioxane using the above copolymer solutions V-1 to V-4 and cuprous oxide were prepared. It was adjusted according to the formulation shown in Table 4. Further, as Comparative Examples 5 and 6, varnishes A and B shown in Table 5 consisting of cuprous oxide and a copolymer of tributyltin methacrylate and methyl methacrylate were used to prepare antifouling paints with the formulations shown in Table 6. . Furthermore, Comparative Examples 7 and 8
As the above, a conventional antifouling paint using copper oxide was prepared by the formulation shown in Table 6.

Using each of the antifouling paints prepared as described above, the storage safety, the degree of wear of the coating film, and the adhesion of aquatic organisms were tested in the following manner.

(Storage stability) With respect to each antifouling paint prepared in Examples 1 to 10 and Comparative Examples 1 to 4, the viscosity at 25 ° C was measured immediately after production, after storage at 50 ° C for 1 month and after storage at room temperature for 1 month. It was measured. The results are shown in Table 7. Comparative samples are all 1
It had gelated after storage for a month.

(Depletion degree of coating film) The antifouling paints obtained in Examples 1 to 10 and Comparative Examples 5 to 8 were
Hard vinyl chloride plates of 70 x 150 x 2 mm each were coated with an applicator so that the dry film thickness would be 100 µm, mounted on a rotating drum installed in seawater, and rotated at a peripheral speed of 10 knots for 1 month later. The consumed film thickness was measured. The results are shown in Table 8.

(Adhesion of Aquatic Organisms) Each of the antifouling paints obtained in Examples 1 to 10 and Comparative Examples 5 to 8 was applied to a steel plate of 100 × 300 × 3 mm coated with an anticorrosion paint, and the dry film thickness was 150 to A sample was prepared by coating so as to have a thickness of 200 μm. These samples were submerged in the sea off Miyajima, Hiroshima Bay as Comparative Example 9 together with untreated samples, and the aquatic organism adhesion area was examined every 6 months. The adhesion area of each sample is shown in Table 9 as a percentage.

As each test result shows, the antifouling coating material of the present invention exhibits stable antifouling property for a long period of time.

Front page continued (72) Inventor Nobuhiro Saito 133 Nishishinmachi, Ota, Gunma Prefecture, Toshiba Silicon Corporation (72) Inventor Akitsu Kurita 133, Nishishinmachi, Ota City, Gunma Toshiba Silicon Corporation (72) ) Inventor Masayuki Hatanaka 133 Nishinishimachi, Ota City, Gunma Prefecture Toshiba Toshiba Corporation

Claims (7)

[Claims] 1. A general formula (A) (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² , R ³ , and R ⁴ are each a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, and a phenyl group. And at least one of them represents a monovalent hydrocarbon group having 4 or more carbon atoms.) And at least one unsaturated triorganosilyl monomer represented by the formula (1), and a (meth) acrylic or vinyl compound. A copolymer obtained by polymerizing at least one kind of organic monomer, (B) copper powder, copper alloy powder and / or copper compound, and (C) fine powder of polymethylsilsesquioxane. Antifouling paint characterized by. 2. The antifouling paint according to claim 1, wherein R ² , R ³ and R ⁴ are all butyl groups. 3. A method according to claim 1, wherein ^two of R ² , R ³ and R ⁴ are methyl groups and the rest are alkyl groups having 6 or more carbon atoms.
Antifouling paint as described in the item. 4. The copolymer according to claim 1, wherein the amount of the unsaturated triorganosilyl monomer in the copolymer monomer is 10 to 95% by weight. Antifouling paint. 5. The antifouling paint according to any one of claims 1 to 4, wherein the blending amount of the component (B) is 10 to 500 parts by weight relative to 100 parts by weight of the component (A). 6. The antifouling paint according to any one of claims 1 to 5, wherein the component (C) has an average particle size of 0.1 to 100 µm. 7. The antifouling paint according to any one of claims 1 to 6, wherein the compounding amount of the component (C) is 0.5 to 300 parts by weight with respect to 100 parts by weight of the component (A).