JPS6136794B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel antifouling coating composition for underwater structures. Ships and underwater structures suffer from various types of damage due to contamination caused by adhesion of marine organisms. Particularly in the case of ships, the development of antifouling paints with excellent antifouling performance is strongly desired from various angles, as energy conservation is discouraged because the frictional resistance of the ship's hull increases, leading to a decrease in speed and an increase in fuel consumption. Conventional antifouling paints use a coating film-forming resin (hereinafter simply referred to as vehicle) that also serves as a support for strong antifouling agents, etc., and mix large amounts of antifouling agents to maintain the antifouling effect as long as possible. However, from the standpoint of environmental protection and resource conservation, recent antifouling paints keep the elution amount of antifouling agents to the minimum necessary amount and elute this amount for as long as possible, that is, control the elution. Way ahead. Two types of ship bottom antifouling paints developed in this direction are currently being put into practical use: dissolving type antifouling paints and diffusion type antifouling paints. Dissolving type antifouling paint has a mechanism in which the surface layer of the antifouling coating reacts with seawater and gradually dissolves, and the antifouling agent is eluted according to the amount of dissolved water.If the dissolution rate can be adjusted to a constant level, the antifouling effect is achieved. The elution rate of the agent can also be adjusted.
However, when used as a ship bottom antifouling paint, uniform dissolution, that is, uniform elution of the antifouling agent, is difficult in reality due to problems such as the dissolution rate varying depending on the position on the bottom of the ship, and future improvements are expected. There is. Diffusion-type antifouling paint uses a water-absorbing polymer as a vehicle, and the antifouling agent dissolves in the seawater in the coating film that absorbs seawater and swells.The dissolved antifouling agent then diffuses through the coating film. If the water absorbency of the vehicle and the diffusibility of the antifouling agent are appropriately selected, it is possible to elute a certain amount of the antifouling agent. However, since toughness is required for the water-absorbing polymer that serves as the vehicle, it is difficult to find a polymer that satisfies both toughness, water absorption, and antifouling agent diffusivity, and polymers with such performance are difficult to find. It often reacts with cuprous oxide, organic tin compounds, etc. that are commonly used as antifouling agents, causing practical problems as paints, and future improvements are expected in this respect. As a diffusion-type antifouling paint, it is well known that a hydrophilic polymer having water absorption and strong underwater coating strength is used for coating the bottom of a ship. No. 53-21886, Japanese Unexamined Patent Publication No. 1973-
It is described in publications such as No. 148791. When such a hydrophilic polymer is applied over an existing antifouling paint, the effect of controlling the elution of the antifouling agent from the antifouling paint can be maintained for a long time, or the special performance of the hydrophilic paint film is to reduce frictional resistance. It has advantages such as improving the fuel efficiency of ships, but in practical use, it requires more painting steps as it is overcoated over existing antifouling paint, and it must be painted with a uniform thickness over the entire surface. If the hydrophilic coating film is thickly coated, the elution of the antifouling agent may be suppressed too much, and in this case, biofouling may be observed. Additionally, there are problems such as the degree of elution control and adhesion of the antifouling agent differing depending on the type of existing antifouling paint used as the base. Under these circumstances, rather than using a hydrophilic polymer as a top coat for existing antifouling paints, it is desirable to develop an antifouling paint that uses a hydrophilic polymer as a vehicle, which is directly mixed with an antifouling agent. However, the antifouling paint using the above-mentioned known hydrophilic polymer as a vehicle has two properties: water absorption and toughness _.
Because these active groups have been introduced, these active groups react with cuprous oxide and organic tin compounds mixed as antifouling agents, reducing the storage stability of the paint and making it impossible to maintain the elution control effect. There is a drawback that there is no In order to solve such problems,
It is necessary to develop a new hydrophilic polymer to serve as the vehicle, which is different from the hydrophilic polymer for the top coat. JP-A-51-7034 relates to a new antifouling paint using a hydrophilic polymer as a vehicle, and a hydrophilic polymer with fewer active groups is introduced as the vehicle. However, in this case,
In order to maintain the toughness as an antifouling paint vehicle, water absorption and antifouling agent diffusivity are insufficient, and the elution control effect of the antifouling agent is unfavorable. In order to control the elution of antifouling agents, it is necessary to first consider the water absorption and diffusivity of the hydrophilic polymer that serves as the vehicle, and in this case, the toughness of the coating film in water may not be necessary. many. The role of a curing agent is to compensate for this, but if a functional group is introduced into a hydrophilic polymer to increase the effect of the curing agent, as mentioned above, antifouling agents such as cuprous oxide and organic tin compounds can be used. There is a risk of reaction, and even if the strength of the underwater coating is improved by the effect of the curing agent, the water absorption rate may decrease. As a result of the inventor's diligent efforts to study the combination of a hydrophilic polymer and a curing agent, as a hydrophilic polymer,
Component (a) that does not react with antifouling agents such as cuprous oxide and organic tin compounds but reacts with curing agents; component (b) that also does not react with antifouling agents and improves water absorption; coating film By discovering a copolymer consisting of a specified composition of the three components (c) that maintains strength and by combining it with the above-mentioned copolymer as a hardening agent, it is possible to improve the toughness of the coating film. The present invention was achieved by discovering a specific epoxy compound that has the ability to maintain the elution control effect without causing almost any decrease in water absorption. That is, the present invention provides (A) (a) general formula CH ₂ = CR ₂ COOCH ₂ CH ₂ NR ₂ R ₃ (wherein, R ₁ is H or CH ₃ , R ₂ and R ₃ have 1 to 1 carbon atoms)
3 represents a hydrocarbon group. )
21 to 49% by weight of a polymerizable monomer having a class amino group (b) General formula CH ₂ = CR ₁ CONR ₄ R ₅ (wherein, R ₄ and R ₅ are H or a hydrocarbon group having 1 to 3 carbon atoms) 21 _{to 49} % by _weight of unsubstituted or N-substituted (meth)acrylamide or _diacetone acrylamide represented by (Represents a hydrocarbon group.) (Meth)acrylic acid esters 21-49 represented by
(B) a hydrophilic acrylic copolymer solution obtained by copolymerizing 1% by weight, or a dispersion in which an antifouling agent containing a tin or copper compound as an active ingredient is dispersed in the solution; It consists of a dispersion liquid in which an antifouling agent containing a copper compound as an active ingredient and/or an antifouling agent containing a tin compound as an active ingredient is dispersed in a solution of an epoxy compound having two or more epoxy groups and an epoxy equivalent of 300 or less. , for underwater construction, where both dispersions (A) and (B) are mixed immediately before use so that the epoxy compound contained in the mixed paint is 10 to 50% by weight based on the hydrophilic polymer. This is a composition for antifouling paint. (A) Component (a) in the liquid has the general formula CH ₂ = CR ₁ COOCH ₂ CH ₂ NR ₂ R ₃ (In the formula, R ₁ is H or CH ₃ , R ₂ and R ₃ have 1 to 3 carbon atoms.
represents a hydrocarbon group. ) is a polymerizable monomer having a tertiary amino group, and is a component that does not react with antifouling agents such as cuprous oxide and organic tin, but reacts with curing agents. If the amount of component (a) used is less than 20% by weight, the crosslinking performance with the epoxy compound will decrease, and the toughness and elution control performance of the formed coating will be unsatisfactory. Usual amounts used are 21-49% by weight, preferably 30-40% by weight. Component (a) represented by the above general formula includes dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, di-n-propylaminoethyl (meth)acrylate, and diisopropylaminoethyl (meth)acrylate. Among them, dimethylaminoethyl methacrylate is particularly preferably used. Component (b) is an unsubstituted or N-alkyl substituted compound represented by the general formula CH ₂ = CR ₁ CONR ₄ R ₅ (wherein, R ₄ and R ₅ represent H or a hydrocarbon group having 1 to 3 carbon atoms). It is acrylamide or diacetone acrylamide, and component (b) does not react with the antifouling agent and contributes to improving the water absorption of the formed coating film. When the amount of component (b) used is 50% by weight or more, the water absorption rate of the coating film increases and the elution performance of the antifouling agent improves, but not only the strength of the coating film but also the coating performance decreases. 20
If it is less than % by weight, the water absorption rate of the coating film will be low and the elution performance of the antifouling agent will be unsatisfactory. Examples of such component (b) include (meth)acrylamide, N-methyl (meth)
Examples include acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, and diacetone acrylamide, and among these, diacetone acrylamide and acrylamide are preferred. Component (c) is a (meth)acrylic ester represented by the general formula CH ₂ = CR ₁ COOR ₆ (wherein, R ₁ is H or CH ₃ R ₆ represents a hydrocarbon group having 1 to 12 carbon atoms). This component contributes to improving the mechanical strength of the formed coating film. If the amount of component (c) used is 50% by weight or more, the coating performance will be good, but the effects of components (a) and (b) will not be fully exhibited, and therefore the elution control effect of the antifouling agent will not be satisfactory. is not obtained. If it is less than 20% by weight, the coating film strength will be insufficient. Specific examples of component (c) include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate,
Examples include 2-ethylhexyl acrylate and lauryl (meth)acrylate, and among these, n-butyl acrylate and ethyl acrylate are particularly preferred. The above components (a) to (c) can be used as appropriate so that the total amount is 100% by weight, but it is expected that the amounts of components (a) to (c) used will vary greatly. That is, the elution control effect performance that can be obtained by satisfying the three conditions of water absorption, antifouling agent diffusivity, and toughness cannot be obtained. From this perspective, the amount of ingredients (a) to (c) used is 21 to
49% by weight, especially 30-40% by weight is preferred. If the mixing ratio of the three components (a) to (c) is significantly different, that is, if one of the three components (a) to (c) is 50% by weight or more or 20% by weight or less, the present invention Therefore, it is impossible to obtain an antifouling paint that can maintain the effect of controlling the elution of the antifouling agent over a long period of time. A new antifouling paint using a hydrophilic polymer as a vehicle is being researched from a completely different perspective than controlling the elution of an antifouling agent (Japanese Patent Publication No. 53-21884), but in this case, the purpose of the present invention is fundamentally 50% by weight or more of the general formula CH ₂ =〓/〓-COOR ₆ (R ₁ is H or CH ₃ , R ₆ is a hydrocarbon having 6 to 12 carbon atoms) to impart water repellency to the coating film. ) It has become essential to use acrylic esters represented by Liquid (A) can be prepared by mixing desired amounts of the components (a) to (c) above and using a solution polymerization method. As a polymerization solvent, ethyl cellosolve, methyl cellosolve,
Cellosolves such as cellosolve acetate; ethanol,
Alcohols such as isopropyl alcohol; aromatic hydrocarbons such as toluene and xylene; as well as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. can be used, and these can be mixed and used if necessary. The polymerization reaction can be carried out at 75°C to 105°C using a known radical polymerization catalyst. Examples of such radical polymerization catalysts include azobisisobutyronitrile, benzoyl peroxide, and tert-butyl peroxide. The polymer solution after the polymerization reaction can be used as it is, or further diluted with a solvent, or if desired, organic tin-based or copper-based antifouling agents, various pigments, additives, etc. can be added as liquid (A). can do. (B) The epoxy compound in the liquid must have two or more epoxy groups at the end of the molecule and have an epoxy equivalent.
No more than 300 epoxy compounds are used. If you simply want to improve the strength of the formed coating,
It is sufficient to have two or more epoxy groups at the end of the molecule, but in order to achieve the elution control effect of the antifouling agent, which is one of the objectives of the present invention, the amount of epoxy resin per 1 g of epoxy group is required. Epoxy compounds with an epoxy equivalent weight, defined by weight, of 300 or less must be used. If an epoxy compound with an epoxy equivalent of 300 or more is used, the effect of controlling the elution of the antifouling agent is insufficient, and the object of the present invention cannot be achieved. Such epoxy compounds having an epoxy equivalent of 300 or less include bisphenol A and epichlorohydrin-based Epicote 827, 828 (trade name, manufactured by Shell Chemical Co., Ltd.); novolac-based Epicote 151, 154, 1031 (trade name, manufactured by Shell Chemical Co., Ltd.); EOCN103 , 104 (Product name, Nippon Kayaku
Co., Ltd.), and Eponite 028 (trade name, Nitto Kasei Co., Ltd.), which is commercially available as a reactive diluent.
) is also suitable as a curing agent in the present invention. All of these epoxy compounds are water-insoluble, and among them, EOCN103, Epicote 1031, Eponite
028 is particularly preferred in the present invention. Although it is unclear in detail how an epoxy compound with an epoxy equivalent of 300 or less contributes to sustaining the elution control effect, it can be crosslinked with the hydrophilic copolymer of the present invention in a preferred form and used as an antifouling coating. This is thought to be to prevent deterioration of water absorption performance and diffusion performance due to reaction with antifouling agents or substances present in the sea. The mixing ratio of the epoxy compound to the hydrophilic copolymer may be 5% by weight or more if the purpose is simply to improve the toughness of the coating film, but it is required to be 10% by weight or more to contribute to sustaining the elution control effect. It is. As the amount of epoxy mixed increases, the elution control sustaining effect improves, but the original performance such as water absorption gradually decreases, so it is not preferable to mix more than 50% by weight. Therefore, it is necessary that the mixing ratio of the epoxy compound to the hydrophilic copolymer is in the range of 10 to 50% by weight, preferably in the range of 20 to 40% by weight. Epoxy compounds that can be used in the present invention include liquid,
Or it is commercially available in solid form. Liquid ones can be used as they are, but solid ones are preferably used after being dissolved in the solvent for liquid (A). As antifouling agents that can be incorporated into the composition of the present invention,
Products containing copper compounds such as cuprous oxide as active ingredients; phenyltin compounds such as triphenyltin hydroxide and triphenyltin chloride; organic compounds such as butyltin compounds such as tributyltin fluoride, bitributyltin α, α dibrom succinate, etc. Antifouling agents containing a tin compound as an active ingredient can be used, but other antifouling agents can also be used if necessary. The mixing amount of these antifouling agents varies depending on the type of antifouling agent used and the place where it is used, but under normal conditions, it is preferably in the range of 10 to 400% by weight based on the resin component. Needless to say, in addition to the antifouling agent, pigments such as red iron oxide, zinc oxide, calcium carbonate, and titanium dioxide, and various additives for improving paint properties can be mixed. When mixing the antifouling agent, compounding agents, filling machine, and pigment, it is advantageous from the viewpoint of storage stability of the coating composition to mix and disperse them in the liquid (B) in advance. . However, in the solution (A) of the present invention, even if an antifouling agent containing a tin or copper compound as an active ingredient is dispersed and stored, it can be stored stably for a long time. The coating composition of the present invention can be applied to a target structure by mixing liquids (A) and (B) before use. When painting, it exhibits sufficient adhesion to commonly used primers and rust preventives. Since the coating composition of the present invention undergoes a curing reaction at room temperature, it does not require post-treatments such as heating or ultraviolet irradiation after painting, but on the other hand, there is sufficient time after mixing for the curing reaction to proceed. It is also advantageous in terms of construction. As mentioned above, the antifouling paint of the present invention is a combination of a special hydrophilic polymer and a special epoxy compound.
A long-term elution control effect can only be achieved by making it a two-component product, and this is a major feature of the present invention. The specific composition of the antifouling paint of the present invention will be explained below using Examples. Unless otherwise specified, all amounts are expressed in parts by weight. Example 1 In a three-neck flask with a capacity of 1 equipped with a thermometer, a reflux condenser, and a stirrer, 30 parts of dimethylaminoethyl methacrylate, 30 parts of diacetone acrylamide, 40 parts of butyl acrylate, and ethyl cellosolve (hereinafter referred to as ECS) as a solvent were added. When 100 parts of a copolymer solution was added as a polymerization catalyst at a concentration of 0.3% per monomer and polymerization was carried out at 90°C for 6 hours, a syrup-like copolymer solution was formed. Obtained. This was called liquid A. As another hardening agent, 20 parts of EOCN103 (manufactured by Nippon Kayaku, epoxy equivalent: 210-230) was dissolved in 20 parts of ECS, followed by 300 parts of cuprous oxide, 40 parts of tributyltin fluoride, 40 parts of red iron oxide, and 120 parts of ECS. In addition, the dispersion machine Paint Conditioner Model
No. 5100 (Red Devil inc.) was used to disperse the mixture to prepare liquid B. The antifouling paint of the present invention was obtained by mixing liquids A and B in the following proportions.

[Table] Example 2 In a container similar to Example 1, 30 g of dimethylaminoethyl methacrylate, 25 g of acrylamide, 45 g of ethyl acrylate, and 50 g of ECG as a solvent.
A copolymer solution was prepared in the same manner as in Example 1 by supplying 50 g of xylene. This was called liquid A. Eponite 028 (manufactured by Nitto Kasei Co., Ltd., epoxy equivalent: 150-160) was used as a curing agent to obtain a B solution having the following composition. Solutions A and B were mixed at the following ratio.

[Table] Example 3 Using the same copolymer solution A as in Example 1, a solution B having the following composition was prepared. Solutions A and B were mixed at the following ratio.

[Table] Example 4 Triphenyltin hydroxide was dispersed in the same copolymer solution as in Example 1 to prepare liquid A, liquid B having the following composition was prepared, and liquids A and B were mixed in the proportions shown below.

[Table] Comparative Example 1 Using the same copolymer solution as in Example 1, dispersion was carried out in the same manner as in Example 1 except that liquid B did not use a curing agent to obtain both dispersions A and B.

[Table] Comparative Example 2 As a curing agent in the B liquid composition of Example 1
Both solutions A and B were prepared in exactly the same manner as in Example 1, except that Epicote 1001 (manufactured by Ciel Chemical, epoxy equivalent: 450-500) was used instead of EOCN103.

[Table] Comparative Example 3 In a container similar to Example 1, 30 parts of dimethylaminoethyl methacrylate, 10 parts of methacrylic acid, 20 parts of diacetone acrylamide, and butyl acrylate were added.
40 parts and 200 parts of ECS as a solvent were supplied, and polymerization was carried out in the same manner as in Example 1 to obtain a copolymer solution.
Both solutions A and B were prepared with the following compositions.

[Table] Comparative Example 4 In a container similar to Example 1, 15 parts of dimethylaminoethyl methacrylate, 25 parts of acrylamide, 60 parts of butyl acrylate, and 100 parts of toluene as a solvent were added.
A copolymer solution was obtained by polymerizing in the same manner as in Example 1. Both dispersions A and B were prepared with the following compositions.

[Table] Comparative Example 5 100 parts of hydroxyethyl methacrylate and 200 parts of ECS were supplied to the same flask as in Example 1, and 0.1% of azobisisobutylnitrile was added to the monomer as a catalyst, and polymerization was carried out at 85°C for 6 hours. A syrup-like solution was obtained. Add cuprous oxide to 300 parts of this solution.
300 parts of tributyltin fluoride, 40 parts of red iron oxide, 40 parts of zinc oxide, and 60 parts of ECS were added and dispersed using a dispersion machine to obtain a one-component paint. For the eight two-component paints of Examples 1 to 4 and Comparative Examples 1 to 4 shown above, after mixing liquids A and B,
Comparative Example 5, which is a one-component paint, was painted directly onto a base-treated steel plate with a brush to prepare a sample plate for an immersion test. A steel plate measuring 100 mm x 300 mm and 1 mm thick was used, and the surface was treated with wash, primer, and anti-corrosion paint. A commercially available vinyl-based anti-corrosion paint was applied in two coats to a target thickness of 80μ. The target thickness of the antifouling paints of Examples and Comparative Examples was 100μ, and in all nine types, the target thickness of 100μ could be achieved with two coats with a brush. All of the nine types were successfully prepared as sample plates, but in the case of Comparative Example 3, the paint gelled 30 minutes after mixing both liquids A and B, making it unsuitable for use as a practical paint. Furthermore, in the case of Comparative Example 5, the viscosity of the paint tends to increase gradually after preparation, which is also not practical from the viewpoint of storage stability. Example 1~
4. Comparative Examples 1, 2, and 4 have practical performance as paints in terms of pot life and storage stability. The sample boards created in this way and sample boards using commercially available dissolving type antifouling paint (commercial product A) and diffusion type antifouling paint (commercial product B) were sold at Niigata East Port in April 1978. Soaking started in April 1978.
The state of biofouling and the elution rate of copper and tin were measured for two years up to the end of the month. The results are shown in Tables 1-3. According to this result,
The reason why the antifouling effect lasts for two years is
It can be said that the characteristics of the present invention have been confirmed, as this is the only composition of the present invention, which is a combination of a hydrophilic copolymer with a special composition and a special epoxy compound.

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Claims (1)

[Claims] 1 (A) (a) General formula CH ₂ = CR ₁ COOCH ₂ CH ₂ NR ₂ R ₃ (wherein, R ₁ is H or CH ₃ , R ₂ and R ₃ have 1 to 1 carbon atoms)
3 represents a hydrocarbon group. ). 21 to 49% by weight of a polymerizable monomer having a tertiary amino group (b) General formula CH ₂ = CR ₁ CONR ₄ R ₅ (wherein, R ₄ and R ₅ are H or carbonized carbon atoms having 1 to 3 carbon atoms) 21 to 49% by weight of unsubstituted or N-alkyl-substituted (meth)acrylamide or diacetone acrylamide (represents a hydrogen group) (c) General formula CH ₂ = CR ₁ COOR ₅ (wherein R ₆ is a carbon number of 1 ~12 hydrocarbon groups) (meth)acrylic acid esters 21-49 represented by
A hydrophilic acrylic copolymer solution obtained by copolymerizing % by weight, or a dispersion in which an antifouling agent containing tin or a copper compound as an active ingredient is dispersed in the solution, and (B) the terminal of the molecule. A dispersion liquid in which an antifouling agent containing a copper compound as an active ingredient and/or an antifouling agent containing a tin compound as an active ingredient is dispersed in an epoxy compound solution having two or more epoxy groups and an epoxy equivalent of 300 or less. Immediately before use, both dispersions (A) and (B) are blended so that the epoxy compound contained in the mixed paint is 10 to 50% by weight based on the hydrophilic copolymer. An antifouling paint composition for underwater structures.