JP2606692B2 - Antifouling paint - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to an antifouling paint for preventing aquatic organisms from adhering to underwater structures, fishing nets, ship bottoms, and the like.

[Technical background of the invention and its problems] Underwater structures, fishing nets, boat bottoms, and other articles that are used for a long time in water will not only have aquatic organisms attached and propagate during use, impairing their appearance, but also impair their functions. May have adverse effects.

In the case of a ship bottom, the attachment of aquatic organisms leads to an increase in the surface roughness of the whole ship, and furthermore, the ship speed decreases and the fuel efficiency increases. This also lengthens the period of repair at the dock and significantly reduces operating efficiency. other than this,
Propagation of bacteria causes decay of underwater structures and deterioration of physical properties, resulting in enormous damage such as a marked reduction in life.

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

A physiologically active substance containing a noble metal such as an organotin compound or cuprous oxide has a particularly excellent antifouling effect and is considered to be an essential component for paints for fishing nets and ship bottoms. For example, U.S. Pat. No. 3,167,473 describes a so-called "polymer type" among antifouling agents using an organotin compound. This antifouling agent has an organotin-containing group in the side chain of the copolymer, and is hydrolyzed in slightly alkaline seawater to release an organotin compound, exhibiting an antifouling effect and being hydrolyzed at the same time. Since the copolymer itself becomes water-soluble and dissolves in seawater, an active surface can always be maintained without leaving a resin residue layer. Japanese Patent Application Laid-Open No. 60-231771 discloses, for the purpose of promoting the dissolution of a physiologically active substance such as an organotin compound or cuprous oxide contained therein,
A method is described in which a hydrolyzable silyl (meth) acrylate, for example, tributylsilyl acrylate or triphenylsilyl (meth) acrylate is used as a part of the monomer of the organotin-containing copolymer used in combination therewith.

However, these antifouling agents have poor storage stability, and have a problem that they gel within a few days especially when cuprous oxide is used in combination. In addition, these antifouling agents contain heavy metals and hydrolyzable organic tin, so they are highly toxic. Organic tin compounds are particularly irritating and cause irritation when touching the skin. In addition, there were serious problems such as marine pollution due to runoff into seawater, generation of malformed fish, and accumulation in the human body due to ecological enrichment.

For this reason, Japanese Unexamined Patent Publication (Kokai) No. 60-500452 describes a ship bottom paint exhibiting an antifouling effect without using an organotin-containing copolymer. This hull bottom paint is composed of a toxic substance and a self-polishing polymer, and the polymer monomer is a hydrolyzable silyl (meth) acrylate such as tris (4-methyl-2-pentoxy) silyl acrylate. Have been.

However, in this ship bottom paint, the self-polishing type polymer only functions as a poisonous substance delivery system and has no antifouling property itself, so that the poisonous component is essential. Even in this ship bottom paint, the basic principle of antifouling of killing aquatic organisms attached by toxic substances is not different from the conventional antifouling agent, and serious environmental problems could not be avoided. In addition, when cuprous oxide is used as a poison, there is a problem that the preservation stability is poor and gelation occurs within a few days. Further, the tris (4-methyl-2-pentoxy) silyl acrylate described herein has a hydrolyzable property because both of the two types of bonds between the silicon atom and the alkoxy group and between the silicon atom and the ester bond are hydrolyzable. In addition, it is difficult to control the solubility of the copolymer in water by water splitting, and in addition, the self-polishing polymer easily depolymerizes under ultraviolet irradiation, and is therefore exposed to direct sunlight. When used in an environment where there is a large amount of ultraviolet rays, such as in the tropics or summer, the coating film may fall off in a short period of time, making it difficult to obtain long-term antifouling properties. Was found.

In addition, the present inventors have previously shown that a copolymer of a silicon-containing (meth) acrylate and an organic monomer exhibits excellent antifouling properties without the use of poisons or heavy metals due to its self-polishing property. However, as a result of further study, it has been found that this copolymer is also easily decomposed by ultraviolet rays when used in places such as near the sea surface where the amount of irradiation of ultraviolet rays is large.

[Object of the Invention] The present invention provides an antifouling paint which does not contain heavy metals or poisons, has no adverse effect on marine ecosystems, has excellent antifouling properties, and has remarkable durability. With the goal.

[Constitution of the Invention] The present inventors have found that the decomposition of the above-mentioned copolymer of a silicon-containing (meth) acrylate and an organic monomer by ultraviolet rays is prevented by benzophenones or benzotriazoles, and as an antifouling paint. The inventors have found that the durability is significantly increased, and have accomplished the present invention.

That is, the antifouling paint of the present invention comprises (A) (a) a general formula CH ₂ = CR ¹ CO ₂ CiR ² R ³ R ⁴ (wherein R ¹ represents a hydrogen atom or a methyl group, and R ² , R ³ ,
R ⁴ represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group or a phenyl group), and (b) a group consisting of (meth) acrylic and vinyl compounds. It is characterized by comprising a silicon-containing polymer having a degree of polymerization of 50 to 190 and being selected from at least one organic monomer containing no silicon atom and (B) benzophenones or benzotriazoles.

The copolymer of the component (A) used in the present invention exhibits appropriate hydrolyzability by selecting an organic group bonded to a silicon atom, and gradually hydrolyzes in water to increase hydrophilicity. Shows a controlled dissolution profile. Such a copolymer can be obtained by polymerizing one or more silicon-containing (meth) acrylates and one or more organic monomers to a degree of polymerization of 50 to 190. Can be Although the composition ratio of the silicon-containing (meth) acrylate and the organic monomer is not particularly limited, the amount of the silicon-containing (meth) acrylate is preferably 10 to 95% by weight, more preferably 20 to 70% by weight. Range. When the amount of the silicon-containing (meth) acrylate is in the range of 10 to 95% by weight, particularly good hydrolysis rate and coating film properties can be obtained, and the antifouling ability can be maintained well for a long period of time.

In the silicon-containing (meth) acrylate that is one of the starting materials of the copolymer (A), R ¹ is a hydrogen atom or a methyl group, and R ² , R ³ , and R ⁴ each have 1 to 18 carbon atoms.
Which 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, a stearyl group and the like are exemplified. As the cycloalkyl group, a cyclopentyl group and a cyclohexyl group are exemplified.

Examples of such a silicon-containing (meth) acrylate include trimethylsilyl acrylate, dimethylbutylsilyl acrylate, dimethylhexylsilyl acrylate, dimethyloctylsilyl acrylate, dimethyldecylsilyl acrylate, dimethyldodecylsilyl acrylate, dimethylcyclohexylsilyl acrylate, dimethylphenylsilyl acrylate, Examples thereof include methyldibutylsilyl acrylate, ethyldibutylsilyl acrylate, dibutylhexylsilyl acrylate, dibutylphenylsilyl acrylate, tributylsilyl acrylate, and triphenylsilyl acrylate; and methacrylates corresponding thereto. Of these, R ² , R ³ , R ⁴ , which have moderate hydrolyzability and thereby control the slow solubility of the antifouling paint in water.
It is preferable that at least one of them has 4 or more carbon atoms. Furthermore, the hydrolysis rate is slow, the synthesis is easy, and the film-forming property is good, R ² , R ³ , R ⁴ such as dimethylhexylsilyl (meth) acrylate and dimethyldecylsilyl (meth) acrylate Among them, those in which two are methyl groups and the rest are long-chain alkyl groups having 6 or more carbon atoms are more excellent. Also, tributylsilyl (meth) acrylate is preferred in order to have a controlled hydrolysis rate in water and obtain a moderately slow solubility.

The organic monomer which is the other starting material of the copolymer of the component (A) is selected from (meth) acrylic and vinyl compounds which do not contain a silicon atom in the molecule. As the (meth) acrylic compound, methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate (the above alkyl group may be linear or branched), 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate , Acrylamide, acrylonitrile and the like; and methacryl compounds corresponding thereto. Examples of the vinyl compound include vinyl acetate, vinyl chloride, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl isobutyl ether, vinyl pyrrolidone and the like. Is done.

The polymerization is carried out, for example, by mixing a silicon-containing (meth) acrylate and an organic monomer in the presence of an organic solvent and using a polymerization initiator.

Organic solvents are used to control polymerization and prevent the formation of gels during the reaction, and are monovalent hydrogen solvents such as benzene, toluene and xylene; ester solvents such as ethyl acetate and butyl acetate; methanol and ethanol. Alcohol-based solvents such as methyl ethyl ketone and methyl isobutyl ketone; and aprotic polar solvents such as dimethylformamide and dimethyl sulfoxide.

The amount of the organic solvent is 2 per 100 parts by weight of the total amount of the monomers.
0 to 1,000 parts by weight is preferable, and 50 to 500 is more preferable.
Parts by weight. By setting the amount of the organic solvent in the range of 20 to 1,000 parts by weight, particularly excellent controllability of the reaction and formation of the antifouling paint can be obtained. In order to avoid hydrolysis during polymerization and during storage, these organic solvents are preferably used after removing water.

Benzoyl peroxide, te
Organic peroxides such as rt-butyl perbenzoate, methyl ethyl ketone peroxide, cumene hydroperoxide and azo compounds such as azobisisobutyronilyl are exemplified.

The amount of the polymerization initiator is generally 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the total amount of the monomers.
Parts by weight.

Polymerization conditions are not particularly limited, but preferably performed in a nitrogen stream, and generally 60 to 120 ° C when the polymerization initiator is an organic peroxide, and 45 to 100 ° C when the azo compound is used.
At a temperature of

The component (B) used in the present invention includes 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzoyloxybenzophenone, phenylsali Benzophenones such as tylate and 4-tert-butylphenyl salicylate; 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di- tert-butylphenyl) -5-chlorobenzotriazole, 2-
Benzotriazoles such as (2'-hydroxy-5'-tert-butylphenyl) benzotriazole are exemplified.

The amount of the component (B) is not particularly limited.
The types of components, the composition of the copolymer, especially the types of R ² , R ³ , R ⁴ ,
Although it depends on the purpose and conditions of use of the antifouling paint,
The range is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the component (A).
By setting the blending amount of the component (B) in the range of 0.01 to 10 parts by weight, a particularly stable effect of suppressing the decomposition of the component (A) and good physical properties of the coating film can be obtained.

The antifouling paint of the present invention comprises a copolymer of the component (A) and (B)
It can be obtained by further blending, if necessary, a pigment, an organic solvent, a thixotropic agent and the like with the benzophenones or benzotriazoles as components. Since the target of the antifouling treatment is as diverse as underwater structures, fishing nets, ship bottoms, and the like, 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. By setting the blending amount of the copolymer in the range of 1 to 60% by weight, particularly good coatability and workability can be obtained.

Examples of the pigment include seawater inactive pigments such as red iron oxide, titanium white, talc, silica, calcium carbonate, and barium sulfate, and seawater reactive pigments such as zinc oxide and calcium oxide. Can be used together.

As the organic solvent, those similar to those used in the polymerization step for obtaining the copolymer described above are used.

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

[Effect of the Invention] The antifouling paint obtained in the present invention increases the hydrophilicity by hydrolysis of the triorganosilyl group in the side chain of the copolymer, and exhibits controlled solubility in water, that is, self-polishing property. Therefore, an excellent antifouling effect can be exerted without using an organotin compound or an organotin-containing copolymer which affects the environment. In addition, it has excellent durability, and retains antifouling properties for a long time even when used in places exposed to sunlight containing a large amount of ultraviolet rays, such as in the tropics and summer.

The composition of the present invention is effective for preventing contamination by aquatic organisms such as underwater structures, fishing nets, and ship bottoms.

[Examples] Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.
In addition, the part in the following examples shows a weight part.

(Synthesis of Copolymer) Synthesis Example 1 300 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 azobisiso Polymerization was carried out by adding 2 parts of butyronitrile and heating and stirring at 80 ° C. for 8 hours. After cooling to room temperature, 66 parts of ethyl acetate was added to obtain a pale yellow transparent copolymer solution V-1. V-1 has a viscosity of 480 cP at 25 ° C.
The solid concentration was 44.8%.

Synthesis Examples 2 to 9 In the same manner as in Copolymer Solution V-1, except that the organic solvent after the polymerization was not added, the organic solvent, silicon-containing (meth) acrylate and the reaction initiator shown in Table 1 were diluted to give a light color. Yellow and transparent copolymer solutions V-2 to V-7 were obtained. The viscosity and solid concentration of the obtained copolymer solution are as shown in Table 1. In addition, the number which shows the compounding quantity in a table | surface represents a part (the same hereafter).

Further, as a comparison with the present invention, a copolymer (H-1) having a low polymerization degree and a copolymer (H-2) having a high polymerization degree were synthesized as follows. First, 300 parts of xylene was charged into a reaction vessel equipped with a cooler, a stirrer, and a thermometer, and 144 parts of tributylsilyl methacrylate, 156 parts of methyl methacrylate, 6 parts of n-octylmercaptan, and 6 parts of azobisisobutyronitrile were added thereto. Was added, and the mixture was heated and stirred at 95 ° C. for 8 hours to carry out polymerization, and then cooled to room temperature to obtain a colorless and transparent low-polymerization degree copolymer solution H-1. H-
1 had a viscosity at 25 ° C. of 48 cP and a solid content of 47.4%.

Further, 300 parts of xylene was charged into a reaction vessel equipped with a cooler, a stirrer and a thermometer, and 144 parts of tributylsilyl methacrylate, 156 parts of methyl methacrylate and 0.6 part of azobisisobutyronitrile were added thereto.
After polymerization by heating and stirring for a period of time, the mixture was cooled to room temperature to obtain a colorless and transparent high-polymerization degree copolymer solution H-2. The viscosity of H-2 at 25 ° C. is 1760 cP, and the solid content concentration is
49.9%.

From the amount of each monomer charged and the yield of the copolymer, it was confirmed that substantially all of the monomers had been polymerized.

Table 1 shows the GPC method for each of the above copolymers (column: TSK-GEL G4000HXL-G20, trade name, manufactured by Toyoso Co., Ltd.).
The number average molecular weight (Mn) determined by 00HXL, solvent: tetrahydrofuran, in terms of polystyrene), and the degree of polymerization calculated by MPC determined by the GPC method and the charged composition of the monomer at the time of copolymer synthesis are also shown.

Examples 1 to 5 and Comparative Example 1 To the copolymer solution V-6 obtained in Synthesis Example 6, 2-hydroxy-4-octoxybenzophenone was added in the amount shown in Table 2 to obtain five types of copolymers. The antifouling paint was adjusted.

Further, as Comparative Example 1, an antifouling paint to which 2-hydroxy-4-octoxybenzophenone was not added was prepared.

Each of these paints is applied to a rigid polyvinyl chloride plate with dimensions of 70 x 150 x 2 mm with an applicator so that the dry film thickness becomes 100 µm, attached to a rotating drum installed in seawater, and at a depth of 1 m (water temperature 25 to 28 ° C) ), The consumable film thickness was measured after two weeks by rotating at a peripheral speed of 10 knots. Table 2 shows the results. As is apparent from the results, the addition of the benzophenones can prevent the copolymer coating from being consumed in a short time.

Examples 6 to 15, Comparative Examples 2 to 13 and Reference Examples 1 to 4 By using the copolymer solutions V-1 to V-7 obtained in Synthesis Examples 1 to 7 according to the formulations shown in Table 3, benzophenones or Each antifouling paint to which benzotriazoles were added was prepared.

In addition, antifouling paints containing no benzophenones or benzotriazoles were prepared by using the same copolymer solutions as Comparative Examples 2 to 11 and blending them as shown in Table 4. Further, as Comparative Examples 12 and 13, antifouling paints using benzophenones or benzotriazoles were prepared using the copolymer solutions H-1 and H-2 according to the formulations shown in Table 3. Apart from this, Reference Example 1
By using the tributyltin methacrylate-methyl methacrylate copolymers (varnishes A and B) shown in Table 5 and the conventional vehicles as Nos. 4 to 4, antifouling paints were respectively prepared according to the formulations shown in Table 6.

Using each of the antifouling paints adjusted as described above, a test of the degree of wear of the coating film and the adhesion of aquatic organisms was performed in the following manner.

(Degree of Consumption of Coating Film) Each of the antifouling paints of Examples 6 to 15, Comparative Examples 2 to 11, Comparative Examples 12 to 13, and Reference Examples 1 to 4 was applied to a 70 × 150 × 2 mm hard vinyl chloride plate. It was applied with an applicator to a dry film thickness of 200 μm, attached to a rotating drum similar to that used in Example 1, and irradiated with a high-pressure mercury lamp at a water depth of 1 m.
This was rotated at a peripheral speed of 10 knots in seawater, and the consumed film thickness for one month was measured. As a result, as shown in Table 7, the coatings of the antifouling paints of the respective examples are more durable than those of the antifouling paints of the comparative examples, and each of the reference examples including the organotin-containing group and the like has a higher durability. It showed the same durability as antifouling paint.
However, the antifouling paint according to the reference example has a high toxicity and has a drawback that it has a bad influence on safety and health, environment, and the like.

(Adhesiveness of Aquatic Organisms) Each of the antifouling paints of Examples 6 to 15, Comparative Examples 2 to 11, Comparative Examples 12 to 13, and Reference Examples 1 to 4 was measured to have dimensions of 100 × 300 ×.
A 3 mm steel plate was applied with an applicator so that the dry film thickness became 100 μm to prepare a sample. Each of these samples and untreated steel sheet were placed at a depth of 50 cm in the sea off Miyajima off Hiroshima Bay.
Was sunk vertically, and the area ratio of aquatic organisms was checked every six months. As a result, as shown in Table 8, the antifouling paints according to the examples had better antifouling effects than the antifouling paints according to the comparative examples, and the antifouling paints according to Reference Examples 1 and 2 containing an organotin-containing group. It showed the same antifouling effect as the stain paint.

As shown by the results of each test, the antifouling paint of the present invention exhibits stable antifouling properties over a long period of time.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Makoto Tsuboi 1-15-2 Yoshishima Higashi, Naka-ku, Hiroshima City, China Paint Co., Ltd. (72) Inventor Saito Nobuhiro 133 Nishishinmachi, Ota City Toshiba Silicone Co., Ltd. ( 56) References, Special Tables Sho 60-500452 (JP, A) "Introduction to Physical Properties of Coatings", Kenji Ueki, January 10, 1972, published by Riko Publishing Co., Ltd., p. 4, p. 125, p. 125-126. Pages 169 to 170

Claims (4)

(57) [Claims] (A) (a) a general formula CH ₂ CRCR ¹ CO ₂ SiR ² R ³ R ⁴ (wherein R ¹ represents a hydrogen atom or a methyl group, and R ² , R ³ ,
R ⁴ represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group, or a phenyl group. And (b) at least one organic monomer selected from the group consisting of (meth) acrylic and vinyl-based compounds and containing no silicon atom. An antifouling paint comprising a silicon-containing copolymer of 50 to 190 and (B) a benzophenone or a benzotriazole. 2. The antifouling paint according to claim 1, wherein at least one of R ² , R ³ and R ⁴ is an alkyl group having 4 or more carbon atoms, a cycloalkyl group or a phenyl group. 3. The antifouling paint according to claim ² , wherein ^two of R ² , R ³ and R ⁴ are methyl groups and the remaining one is an alkyl group having 6 or more carbon atoms. 4. The antifouling composition according to claim 1, wherein the amount of the silicon-containing (meth) acrylate in the copolymer monomer is 10 to 95% by weight. paint.