JP2651167B2 - Antifouling paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention is an antifouling paint for preventing aquatic organisms from adhering to underwater structures, fishing nets, ship bottoms, and the like, and is particularly effective in an environment having a low ultraviolet intensity. An antifouling paint.

[Technical background of the invention and its problems] Conventionally, a coating film is formed by, for example, coating on the bottom of a ship, and the coating film gradually dissolves in seawater to exhibit a fresh surface, and exhibits a biological activity. Antifouling paints that release tin compounds and prevent the growth of attached organisms are known.
As such an antifouling paint, there is a copolymer of (meth) acrylic acid ester and tributyltin (meth) acrylate, and a combination of tributysilyl acrylate and triphenylsilyl acrylate as a part of the monomer is known. (See JP-A-60-231771). However, the presence of totibutyltin in the molecule, such as in such a copolymer, is seriously problematic in that it is released into seawater by hydrolysis and contaminates the ocean due to its toxicity.

As a group having the same hydrolyzability, a triorganosilyl group introduced into a side chain of a (meth) acrylic polymer is known, and a triorganosilyl (meth) having such a group is known.
A sol homopolymer (see Japanese Patent Application Laid-Open No. 62-179514) has a slow solubility in sea water and a slow-dissolving bottom paint using a copolymer of the above (meth) acrylate and an ethylenically unsaturated monomer. Disclosed (U.S. Pat.
593,055).

Such a triorganosilyl (meth) acrylate homopolymer or copolymer has the advantage that it does not release toxic organotin compounds or the like by hydrolysis. However, this copolymer has a problem that it is easily decomposed by ultraviolet rays when used in a place such as near the sea surface where a large amount of ultraviolet rays is irradiated.

Therefore, the present inventors have previously found that the decomposition by ultraviolet rays can be controlled by blending the above copolymer with an ultraviolet absorber. This is an effective means for use in environments exposed to large amounts of ultraviolet light, such as in summer or near the waterline, but on the other hand, in dark places where light does not reach, such as the bottom of a ship, or in the winter or in the North Ocean, In an environment with low levels of triorganosilyl (meth) acrylate and no silicon atom (meth)
A copolymer obtained from an acrylic compound or a vinyl compound by a usual polymerization method does not show sufficient degradability,
A sufficient effect cannot be obtained as a slowly dissolving antifouling paint.

[Object of the Invention] An object of the present invention is to provide an antifouling paint which does not contain heavy metals and poisons, has no adverse effect on marine ecosystems, and shows sufficient slow-solubility even in an environment with a small amount of ultraviolet rays. It is in.

[Constitution of the Invention] The antifouling paint of the present invention comprises: (A) a general formula (I); Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents a monovalent hydrocarbon group having a bicycloheptane ring, a triorganosyl (meth) acrylate unit represented by the formula:
And (B) general formula (II); (Wherein, R ³ represents a hydrogen atom or a methyl group, and Z represents a monovalent group containing no silicon atom).
Acrylic unit or vinyl unit, 10 to 90 mol%, provided that the unit (B) represented by the general formula (II) includes:
Z represents —CO ₂ QNR ⁴ R ⁵ group (wherein Q represents an alkylene group;
⁴ and R ⁵ each represent an alkyl group).
% By mole of the copolymer.

(A) which is a structural unit of the copolymer used in the present invention.
The unit is a triorganosilyl (meth) acrylate unit represented by the general formula (I).

The definitions of R ¹ and R ^{2 in} the formula are as described above. Examples of R ² include a monovalent hydrocarbon group having a bicycloheptane ring such as a norbornyl group and an ethylidene-ribornyl group. In addition, it has moderate hydrolyzability,
In order to impart appropriate slow solubility to the coating material, it is preferable that at least one of R ² bonded to each silicon atom is a hydrocarbon group having 4 or more carbon atoms.

Examples of the monomer forming the unit (A) include two methyl groups bonded to a silicon atom and one bicycloheptane ring such as dimethylnorbornylsilyl acrylate and dimethyl (ethylidenenorbornyl) silyl acrylate. Triorganosilyl acrylate having a containing group;
And silyl methacrylate corresponding thereto. Two or more of these monomers can be used in combination.

The content of the unit (A) in the copolymer is from 10 to 90 mol%, preferably from 20 to 70 mol%. When the content of the unit (A) is less than 20 mol%, a required hydrolysis rate cannot be obtained, and sufficient antifouling properties cannot be exhibited. On the other hand, if it exceeds 90 mol%, the physical properties of the coating film are poor, and the hydrolysis rate in a normal state becomes excessive, so that the coating film is dissolved in a short time and the antifouling power is not maintained.

The (B) unit represented by the general formula (III), which is a constitutional unit of the copolymer used in the present invention, is a (meth) acrylic unit or a vinyl unit.

The definitions of R ³ and Z in the formula are as described above. Here, examples of the monovalent group not containing a silicon atom of Z include a chlorine atom, an acetoxy group, a phenyl group, an alkoxy group, a pyrrolidone ring, an ester bond-containing group, an amide bond-containing group, a cyano group, and the like. . In the unit (B), a predetermined amount of the monovalent group of Z is -CO ₂ QNR ⁴ R ⁵
(Wherein Q represents an alkylene group and R ⁴ and R ⁵ each represent an alkyl group). Thus, by introducing -CO ₂ QNR ⁴ R ⁵ group in a part of Z, it is possible to accelerate the hydrolysis of the triorganosilyl groups of the resulting copolymer.

The monomer (Z is -CO ₂ QNR ⁴ R) forming the unit (B)
⁽ Other than ⁵ groups) can be exemplified by (meth) acrylic and vinylic compounds containing no silicon atom.

Examples of (meth) acrylic compounds include methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylamide, acrylonitrile, and the like; and methacrylic compounds corresponding thereto. can do. Examples of the vinyl compound include vinyl chloride, styrene, vinyl acetate, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl isobutyl ether, vinyl pyrrolidone, and the like.

The content of the (B) unit in the copolymer is 10
9090 mol%, preferably 30-80 mol%.
If the content of the unit (B) is less than 10 mol%, the physical properties of the coating film are poor, and if it exceeds 90 mol%, the required hydrolysis rate cannot be obtained, and sufficient protection cannot be obtained. Unable to demonstrate soiling.

(B) The definition of Q, R ⁴ and R ⁵ when Z is a —CO ₂ QNR ⁴ R ⁵ group in the unit is as described above. Where Q
Examples of the alkylene group include ethylene, trimethylene, tetramethylene, hexamethylene, and propylene. The alkyl group of R ⁴ and R ⁵ is an alkyl group which may be different from each other, and is a methyl group, an ethyl group, a propyl group, a butyl group,
Examples include a pentyl group, a hexyl group, an octyl group, a decyl group, and a dodecyl group.

When Z is —CO ₂ QNR ⁴ R ⁵ group, monomers forming a tertiary amino group-containing (meth) acrylate unit include dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl acrylate,
Acrylates such as diethylaminopropyl acrylate and methacrylates corresponding thereto can be exemplified.

Z is -CO ₂ QNR ⁴ R ⁵ group (B) content in the copolymer of the units is 0.01 to 20 mol%, preferably 0.
1 to 10 mol%. If the content in this case is less than 0.01 mol%, there is no effect of promoting hydrolysis, and 20 mol%
If it exceeds, the physical properties of the coating film are poor.

The copolymer of the present invention is composed of the units (A) and (B), and the average degree of polymerization of the copolymer, that is, the sum of the units (A) and (B) is preferably 50 to 10,000. More preferably, it is 50 to 500. When the degree of polymerization is less than 50, the film-forming property is low, and when it exceeds 10,000, the solubility of the formed coating film in water is low.

The copolymer used in the present invention is produced, for example, by mixing a silicon-containing (meth) acrylate and an organic monomer in the presence of an organic solvent, and performing copolymerization using a polymerization initiator. Can be.

Organic solvents are used to control polymerization and prevent gel formation during the reaction, and include hydrocarbon solvents such as benzene, toluene and xylene; ester solvents such as methyl acetate and butyl acetate; alcohols such as methanol and ethanol. System dissolution; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; and aprotic polar solvents such as dimethylformamide and dimethyl sulfoxide. It is preferable that the organic solvent be previously removed from water in order to prevent hydrolysis during polymerization and storage.

The amount of the organic solvent used is preferably 20 to 1,000 parts by weight, more preferably 50 to 100 parts by weight based on the total amount of the monomers of 100 parts by weight.
~ 500 parts by weight. If the amount of the organic solvent is too small, it is difficult to control the reaction. If the amount is too large, a concentration step is required when producing an antifouling paint.

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

The amount of the polymerization initiator to be used is generally 0.01 to 10 parts by weight relative to 100 parts by weight of the total amount of the monomers, preferably 0.1
-5 parts by weight.

Although the polymerization conditions are not particularly limited, it is preferable to carry out the polymerization in a nitrogen stream, and in general, when the polymerization initiator is an organic peroxide, the polymerization is carried out at 60 to 120 ° C, and when the azo compound is used, the polymerization is 45 to 100 ° C. To carry out polymerization.

The antifouling paint of the present invention contains the above-mentioned copolymer as a main component, but if necessary, a pigment, an organic solvent, a thixotropic agent,
An ultraviolet absorber or the like can be blended. The mixing ratio of such optional components cannot be limited because the target of the antifouling treatment is various, such as underwater structures, fishing nets, and ship bottoms, but is preferably 1 to 60% by weight based on the copolymer. When the amount is too small, it is difficult to form a coating film, and when the amount is too large, the apparent specific gravity increases,
Workability decreases.

Examples of the pigment include seawater inert pigments such as red iron, titanium white, talc, silica, calcium carbonate, and barium sulfate, and seawater reactive pigments such as zinc oxide and calcium oxide. One or more of these can be used.

As the organic solvent, the same solvents as those used for producing the above copolymer can be used.

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

As the ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone,
2-hydroxy-4-benzoyloxybenzophenone,
Benzophenones such as phenyl salicylate and 4-tert-butylphenyl salicylate; 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2-
(2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-
Benzotriazoles such as (hydroxy-5'-tert-butylphenyl) benzotriazole can be exemplified.

[Effects of the Invention] The antifouling coating composition of the present invention has a triorganosilyl group in the side chain of the copolymer, which is catalyzed by a tertiary amino group introduced by copolymerization, even in an environment where ultraviolet light or the like does not exist. Hydrolysis is performed at a moderate rate to increase hydrophilicity, and controlled slow-solubility in water, that is, self-polishing, so that there is no need to use an organotin compound or an organotin-containing copolymer that affects the environment. Excellent antifouling effect can be exhibited.

EXAMPLES Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. In these examples, parts represent parts by weight.

Example 1 A reaction vessel equipped with a cooler, a stirrer and a thermometer was charged with 100 parts of xylene, and 50 parts of dimethyl (ethylidene norbornyl) silyl acrylate, 45 parts of methyl methacrylate, 5 parts of butyl acrylate, and dimethylaminoethyl methacrylate were added. 5 parts and 1.0 part of azobisisobutyronitrile were added, and the mixture was heated and stirred at 80 ° C. for 8 hours to carry out polymerization. After completion of the polymerization, the resultant was cooled to room temperature, and then filtered to obtain an antifouling paint composed of a pale yellow transparent copolymer solution. This antifouling paint has a viscosity of 820 cP at 25 ° C.
And the solids concentration was 47.3%.

Example 2, Comparative Example 1 An antifouling paint composed of a pale yellow transparent copolymer solution was obtained in the same manner as in Example 1 using the monomers and the polymerization initiator shown in Table 1. The viscosity and solid content of each of the obtained antifouling paints were as shown in Table 1.

Next, using each of the antifouling paints obtained in Examples 1 and 2 and Comparative Example 1, 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 obtained in Examples 1 and 2 and Comparative Example 1 was applied to a 70 × 150 × 2 mm hard vinyl chloride plate with an applicator so that the dry film thickness became 100 μm. . Next, the film was attached to a rotating drum installed indoors, immersed in seawater, and then rotated at a peripheral speed of 10 knots to measure the consumed film thickness for one month. Table 2 shows the results.

A similar test was conducted in the sea at a depth of 1 m. Table 2 also shows the results.

Adhesion of aquatic organisms Each of the antifouling paints obtained in Examples 1 and 2 and Comparative Example 1 was applied to a steel plate of 100 × 300 × 3 mm, and the dry film thickness was 150 to
A sample was prepared by applying the solution to 200 μm using an applicator. These samples and an untreated test as Comparative Example 2 were each immersed in a dark place below the pier, and the area of attachment of aquatic organisms was periodically examined. The results are shown in Table 3. The indication is the percentage of the area of the aquatic organism attached to the surface area of the sample.

Claims (3)

(57) [Claims] (1) (A) a general formula (I); (Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a monovalent hydrocarbon group having a bicycloheptane ring), a triorganosilyl (meth) acrylate unit represented by the formula:
(B) general formula (II); (Wherein, R ³ represents a hydrogen atom or a methyl group, and Z represents a monovalent group containing no silicon atom).
Acrylic unit or vinyl unit, 10 to 90 mol%, provided that the unit (B) represented by the general formula (II) includes:
Z represents —CO ₂ QNR ⁴ R ⁵ group (wherein Q represents an alkylene group;
⁴ and R ⁵ each represent an alkyl group).
An antifouling paint characterized in that it contains, as a main component, a copolymer consisting of: 2. The content of the unit (A) in the copolymer is as follows:
The antifouling paint according to claim 1, wherein the amount is 20 to 70 mol%. 3. The antifouling paint according to claim 1, wherein the content of the tertiary amino group-containing (meth) acrylate unit in the copolymer is 0.1 to 10 mol%.