JPH03247673A - Undercoating composition for silicone-based antifouling coating and method for forming antifouling film - Google Patents

Abstract

PURPOSE:To obtain the subject undercoating composition, containing an epoxy resin as a substrate resin and a specific amount of an aminoalkoxysilane compound having >=2 active hydrogen groups as a curing agent and capable of providing films excellent in antifouling properties, durability, etc. CONSTITUTION:The objective undercoating composition for antifouling coatings containing (A) an epoxy resin such as a polyhydric phenol-epihalohydrin condensate type epoxy resin as a substrate resin and (B) an aminoalkoxysilane compound such as gamma-aminopropyltrimethoxysilane having >=2 active hydrogen groups as a curing agent at 0.4-3.6 equiv. ratio of the active hydrogen groups in the component (B) to the above-mentioned epoxy groups in the aforementioned component (A).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the application of silicone paint to the surfaces of ships, offshore structures, power plant water conduit pipes, etc. for the purpose of preventing biological fouling in water. The present invention relates to an undercoat composition for silicone-based antifouling paints that contributes to improved properties, and a method for forming an antifouling coating film that has a long-term biofouling prevention effect.

(Prior art and its problems) Conventionally, silicone-based paints intended for antifouling have a property that the surface of the paint film is in a low surface energy state, which has a very significant anti-adhesion effect on marine organisms. However, because of these characteristics, coatings made of silicone paints do not have sufficient adhesion to the underlying conventional anticorrosion coatings or other anticorrosion-treated surfaces. However, there is a problem that peeling easily occurs between the two coatings (and the desired antifouling performance is not fully exhibited), and it is desirable to develop a method to effectively utilize the coating film made of silicone-based paint. It was rare.

(Means for Solving the Problems) As a result of extensive research to overcome the above problems, the present inventors have discovered that an epoxy resin and an aminoalkoxy resin having at least two or more active hydrogen groups can be used as an undercoat for silicone paints. A coating composition containing a silane compound in a specific functional group ratio is very effective, and by using this coating composition as an undercoat for a silicone-based antifouling paint, it is possible to bond the surface to be coated with the silicone-based coating film. The present invention was completed based on the discovery that the adhesive property is significantly improved, and furthermore, it contributes to the antifouling properties and durability of an antifouling coating film.

That is, the present invention provides a coating composition containing an epoxy resin as a base resin and an aminoalkoxysilane compound having at least two or more active hydrogen groups as a curing agent, which The equivalent ratio of active hydrogen groups in the alkoxysilane compound is 0.
4 to 3.6, further comprising an epoxy resin as a base resin and an aminoalkoxysilane compound having at least two or more active hydrogen groups as a curing agent. Contains as,
and the equivalent ratio of the active hydrogen group in the aminoalkoxysilane compound to the epoxy group in the epoxy resin is 0.4.
The present invention relates to a method for forming an antifouling coating film, which comprises applying an undercoat composition having a composition of 3.6 to 3.6 to a surface to be coated, and after drying, applying a silicone antifouling coating.

The coating film made from the primer coating composition of the present invention has the inherent characteristics of corrosion resistance and durability of the epoxy resin coating film due to the crosslinking between the epoxy group in the epoxy resin and the amino group in the aminoalkoxysilane compound. The aminoalkoxysilane achieves adhesion to the surface being coated, while the aminoalkoxysilane
Alkoxysilane groups, which are two functional groups, and/or silanol groups generated by hydrolysis of the alkoxysilane groups are oriented on the coating surface and are present in the top coat during the formation of the silicone coating, which is the top coat. The alkoxysilane group or acyloxysilane group reacts with the silanol group generated by hydrolysis or the hydroxyl group present at the end of the molecule to form a bond, resulting in very good adhesion with the silicone top coat. , it exhibits a very remarkable effect as an undercoat film for silicone-based antifouling coatings.

Details will be explained below.

The epoxy resin used as the base resin in the base coating composition of the present invention can be widely used, and generally has a number average molecular weight of about 350 to about 4,000, preferably about 900 to about 3,000, and an epoxy equivalent of is 150
- 3800, preferably 450 to 2100, which are solid or liquid at room temperature. Examples of epoxy resins that can be applied include mechanical properties of cured coatings, adhesion to metal substrates, and anticorrosion properties. From the viewpoint of polyhydric phenol (
For example, preferred are bisphenols)-epihalohydrin condensation type epoxy resin, phenol formaldehyde condensation type epoxy resin, and polymerized fatty acid type epoxy resin.

Examples of the polyhydric phenol-dibihalohydrin condensate type epoxy resin include bisphenol A, bisphenol F, and a condensate of halogenated bisphenol A and epichlorohydrin [e.g., Epicote 82 manufactured by Nisiel Chemical Co., Ltd.
8, Epicote 1001, Epicote 1002, Epicote 1004, Epicote 1007, Epicote 100
Examples of phenol-formaldehyde condensate type epoxy resins include glycidyl etherified novolac type epoxy resins [e.g., manufactured by Nigel Chemical Co., Ltd.
Examples of polymerized fatty acid type epoxy resins include timer acid type epoxy resins [e.g. Epicote 87 manufactured by Nisiel Chemical Co., Ltd.];
2 etc. are used. Among these, polyhydric phenol-ebihalohydrin condensate type epoxy resin is particularly suitable in the present invention. These epoxy resins can be used alone, or in combination of two or more. In addition, lower polyhydric alcohols and those having relatively low molecular weight based on the glycidyl ether of polyester polyols can also be used.

It is essential for the aminoalkoxysilane compound used together with the curing agent in the primer coating composition of the present invention to have at least two or more active hydrogen groups, and as such an aminoalkoxysilane compound, mainly The following (1) to (1v) can be exemplified.

(i) The following - Formula % Formula % () (In the formula, R3 represents an alkylene group having 1 to 8 carbon atoms or a phenylene group, and R2, R- and R4 are the same or different and each has 1 to 4 carbon atoms. alkoxyl group or carbon number 1
~4 alkyl group is shown. However, at least one of R2, R3, and R4 is an alkoxyl group. ) An aminoalkoxysilane compound represented by
Typical examples include γ-aminopropyltrimethoxysilane,
Examples include γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyljethoxysilane, γ-aminopropyltributoxysilane, and c-aminophenyltrimethoxysilane.

(jl) The following formula (wherein R1 represents an alkylene group having 1 to 8 carbon atoms, a phenylene group or a carbonyl group, RI' represents an alkylene group having 1 to 8 carbon atoms or a phenylene group, R2, R3, R
4 are the same or different and each represents an alkoxyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms. However, R
At least one of 2, Rs and R4 is an alkoxyl group. ) An aminoalkoxysilane compound represented by
Representative examples include N-(2-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)-γ-aminopropylmethyldimethoxysilane, and N-(2-aminoethyl)-γ-aminopropylmethyldimethoxysilane.
-(2-aminoethyl)-γ-aminobutyltrimethoxysilane, N-(2-aminophenyl)-γ-aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N -(2-aminophenyl)-γ-aminopropyltrimethoxysilane and the like.

0ii) The following formula (wherein R1 represents an alkylene group having 1 to 8 carbon atoms or a phenylene group, and R2, R3 and R4 are the same or different and each represents an alkoxyl group having 1 to 4 carbon atoms or a phenylene group having 1 to 4 carbon atoms)
~4 alkyl group is shown. However, at least one of Rz, R3, and R4 is an alkoxyl group. ) An aminoalkoxysilane compound represented by
A typical example is N-(2-ureidoethyl)-γ-aminopropyltrimethoxysilane (manufactured by Toshi Silicone Co., Ltd., A
X43-031), N-(2-ureidoethyl)-γ-
Examples include aminopropyltriethoxysilane, N-(2-ureidophenyl)γ-aminopropyltrimethoxysilane, and the like.

(iv) The following formula (wherein R5 represents an alkylene group having 1 to 8 carbon atoms, a phenylene group, or a carbonyl group, R1', Rr'' represents an alkylene group having 1 to 8 carbon atoms or a phenylene group, and R2 ，
R3゜R4,Rs, R6, R7 are the same or different and each is an alkoxyl group having 1 to 4 carbon atoms or 1 to 4 carbon atoms
represents an alkyl group. However, R2, Rs, R4 and R
5, R-, R? At least one of them is an alkoxyl group. ] An aminoalkoxysilane compound represented by
Representative examples include N,N'-bis(trimethoxysilylpropyl)ethylenediamine, N,N'-bis(triethoxysilylpropyl)ethylenediamine, N,N'-bis(trimethoxysilylpropyl)P-phenylenediamine, N , N'bis(trimethoxysilylpropyl)urea, and the like.

In addition to <i) to (iv) above, N,N'-bis(tributoxysilyl)ethylenediamine and the like can also be used.

The aminoalkoxysilane compounds exemplified above can be used alone or in combination of two or more. Among the aminoalkoxysilane compounds (I) to (iv) above, (1) is particularly preferred, and N-(2-aminoethyl)-γ-aminopropyltrimethoxysilane is preferably used from the viewpoint of handling. .

In the primer coating composition of the present invention, the blending ratio of the epoxy resin and the aminoalkoxysilane compound is such that the equivalent ratio of the active hydrogen group in the aminoalkoxysilane compound to the epoxy group in the epoxy resin is 0.4 to 3.6. ．． It is preferably determined to be within the range of 0.6 to 2.4. In the present invention, the active hydrogen group means a reactive hydrogen atom bonded to a nitrogen atom such as an amino group.

If the active hydrogen group/epoxy group equivalent ratio is less than 0.4, not only will the curability and physical properties of the coating decrease (but it will also affect the adhesion of the silicone paint as the top coat). The alkoxysilane group and/or the silanol group generated by hydrolysis of the alkoxysilane group are reduced by reaction with the epoxy group, which is undesirable because the adhesion with the top coat decreases.On the other hand, the above equivalent ratio If the value exceeds 3.6, the amine will be in large excess, and the unreacted amino compound will delay the drying and curing of the silicone-based top coat, making it difficult to form the top coat for antifouling purposes. This is not preferable because it has an adverse effect and further reduces the adhesion of the silicone coating film.

Of course, the aminoalkoxysilane compound mentioned above can be used alone as a curing agent in the undercoat composition of the present invention, but various polyamide resins and primary polyamines commonly used as curing agents for epoxy resins can also be used. There is no problem even if adducts and the like are used in combination with the above aminoalkoxysilane compound.

Furthermore, even when a polyamide resin or a primary polyamine adduct is used in combination with an aminoalkoxysilane compound as a curing agent, in terms of curability, etc., it is important not to exceed the upper limit of the active hydrogen group/epoxy group equivalent ratio. desirable.

The primer coating composition of the present invention may contain colored pigments (
(e.g. titanium dioxide, carbon black, iron oxide, aluminum powder, phthalocyanine blue, etc.), extender pigments (e.g. calcium carbonate, barium sulfate, talc, clay, etc.), anti-rust pigments (e.g. red lead, basic lead chromate, (zinc kilomate, zinc molybdate, aluminum phosphate, zinc powder, etc.), as well as paint additives such as anti-sagging agents, plasticizers, surface conditioners, and anti-settling agents that are used in regular paint manufacturing. A curing catalyst can also be used if necessary.

The above-mentioned primer coating composition can be applied to the surface to be coated by any commonly used known method, such as brush coating,
Examples include roller coating, air spray method, and airless spray method. Moreover, the above-mentioned undercoat paint composition can be used alone as an anticorrosive paint on surfaces to be coated such as steel plates due to its excellent anticorrosive properties, but the surface to be coated may be used on known anticorrosive surfaces. It is more preferable that the material be treated or coated with anti-corrosion paint.

The coating amount of the above-mentioned undercoat paint composition is not particularly limited (selected) depending on the application, but a film thickness of 20 to 200 μm is preferable for M. In the method of the present invention, the above-mentioned undercoat composition is applied to the surface to be coated. After drying at room temperature or by heating, specifically, after drying at room temperature for about one day, a silicone antifouling paint is applied.

The above-mentioned silicone-based antifouling paint is one whose main component is a silicone resin having a site where a curing-reactive functional group such as a hydroxyl group or an alkoxy group is directly bonded to Si, or a silicone compound containing a hydroxyl group at the end, etc. can be applied, and a wide range of known silicone resins can be used. Specifically, KE as a silicone resin
42RTV, KE45TS, KR2706, KE42S
-RTV (manufactured by Shin-Etsu Chemical Co., Ltd.), 5E9140
．． 5H237 (manufactured by Toshi Silicone Co., Ltd.), FSXR
-2622 (manufactured by Dow Corning) and the like.

The above-mentioned silicone-based antifouling paint may contain chlorinated paraffin, solid paraffin, liquid paraffin, silicone oil, etc. as necessary, and may also contain pigments such as extender pigments, coloring pigments, and anticorrosive pigments, plasticizers, Anti-sagging agents, antifouling agents, curing catalysts, etc. can be added.

The silicone-based antifouling paint is applied onto the coating film made of the base coat composition by a normal coating method, and the top coat film made of the paint is dried at room temperature or by heating, specifically, at room temperature. It is formed by curing and drying at (about 20°C) for about one week.

(Thus, the antifouling coating film formed by the method of the present invention using the undercoat paint composition of the present invention and the silicone antifouling paint is
Not only has the adhesion of the alkoxysilane-based topcoat film in the undercoat film been significantly improved, but also the crosslinking reaction between the functional groups of the alkoxysilane groups and/or silanol groups in the undercoat film occurs simultaneously with the curing reaction. A more dense coating film is formed, which has excellent weather resistance and durability, and contributes to the prevention of biofouling over a long period of time as an antifouling coating film.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, "parts" and "%" each refer to "parts by weight".
and “% by weight”.

Examples 1-6. Comparative Examples 1 to 3 As shown in Table 1, undercoat paint compositions of Examples and Comparative Examples were obtained by combining an epoxy resin paint base and a curing agent such as each aminoalkoxysilane compound. In the table,
The blending ratio is expressed as solid content.

Next, apply a zinc epoxy shop primer (dry film thickness 15 μm) to a 10100 x 300 x 2 sandblasting board.
) and on which an epoxy anti-rust paint (200 μm thick) was applied beforehand, each of the above-mentioned undercoat paint compositions was applied to a dry film thickness of 50 μm, and the surface was further coated with silicone paint S1 ( Note 6) or 5-2 (Note 7) was applied to give a dry film thickness of 100 μm to obtain coated plates with antifouling coatings of Examples and Comparative Examples as shown in Table 1.

After drying the above coated plate at room temperature (20°C) for a week, it was immersed in the sea at a depth of 50 cm from a raft for 3 and 6 months to evaluate the antifouling performance and adhesion of the coated plate, and the outdoor exposure for 3 and 6 months. The adhesion of the coated plate was then evaluated. The evaluation results are the same (shown in Table 1).

a to c in the table, (Note 1) to (Note 7) and (*1) to (*
3) is as follows.

a. Epoxy resin paint base - 1 Steel ball mill with Epicoat 1001 (manufactured by Shell Chemical Co., Ltd., trade name,
Epoxy equivalent 450-490, number average molecular weight 900)
epoxy resin to toluene/methyl isobutyl ketone/
Cellosolve = Solid content dissolved in 3/2/1 mixed solvent 6
500 parts of 0% varnish, 100 parts of red iron, 15 parts of talc
0 parts, 20 parts of Tarene 5200 (anti-sagging agent manufactured by Kyoeisha Yushi Co., Ltd.) and 230 parts of thinner for dilution (xylene/n-butyl alcohol/cellosolve = 3/1/1).
After dispersing for 0 hours, epoxy resin paint Base 1 was obtained.

Science, epoxy resin paint base-2: DER664 (manufactured by Dow Chemical Company, trade name, epoxy equivalent weight 875-975
epoxy resin) and DEN439 (manufactured by Dow Chemical Company,
(Product name, epoxy resin with epoxy equivalent weight 191-210)
solids weight a.

600 parts of varnish with a solid content of 60% dissolved in the same mixed solvent as above at a ratio of 3/1, 100 parts of talc, 100 parts of silica, and 50 parts of titanium white were dispersed in the same manner as epoxy resin paint base-2. I got it.

Deaf, epoxy resin paint base-3 = Epicote 1007
(Manufactured by Shell Chemical Co., Ltd., trade name, epoxy equivalent: 1750-2
100, epoxy resin with number average molecular weight of 2900) 6
50 parts of 0% varnish, 300 parts of 60% varnish of Epicoat 1001, Ebiko 1-154 (manufactured by Shell Chemical Co., Ltd.,
150a of 60% varnish (trade name, epoxy equivalent: 176-182).

(both varnishes were prepared by dissolving them in the same mixed solvent as Φ above), 100 parts of Harita, 150 parts of aluminum phosphate, 50 parts of Red Garla, Modaflow (dispersed in rice to obtain epoxy resin paint base-3) .

(Note 1) KBM903: γ-Aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) Fun (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) (Note 5) Tomide 215X: Boryamide resin (manufactured by Fuji Kasei Co., Ltd., product name) Name) S-1: A silicone paint containing KE45TS (manufactured by Shin-Etsu Kasei Kogyo Co., Ltd., trade name, silicone resin) and liquid paraffin in a weight solids ratio of 100:15.

S-2: 5H237 (manufactured by Toshi Silicone Co., Ltd., product name,
Silicone-PGM is a mixture of silicone resin (Silicone resin) and Rough-in (Note 7) (Note 6) in a weight solids ratio of 80:20.

Evaluation items (*l) Antifouling property: The presence or absence of abnormalities in the appearance of the coating film of the test coated plates after immersion for 3 months and 6 months and the state of biofouling were observed.

(*2) Adhesiveness = The surface of the test coated plate after immersion for 3 months and 6 months is scratched with a knife in a cross pattern that reaches the base material, and the tip of the knife is inserted into the crossed tip and peeled off. I saw it.

○: Good △: Slightly bad Evaluation was made in the same manner as in 2).

Claims (1)

[Scope of Claims] 1. A coating composition comprising an epoxy resin as a base resin and an aminoalkoxysilane compound having at least two or more active hydrogen groups as a curing agent, which An undercoat paint composition for a silicone-based antifouling paint, characterized in that the equivalent ratio of active hydrogen groups in the aminoalkoxysilane compound is from 0.4 to 3.6. 2. An epoxy resin is used as a base resin, an aminoalkoxysilane compound having at least two or more active hydrogen groups is contained as a curing agent, and the active hydrogen group in the aminoalkoxysilane compound relative to the epoxy group in the epoxy resin is A method for forming an antifouling film, which comprises applying an undercoat composition having an equivalent ratio of 0.4 to 3.6 onto a surface to be coated, and after drying, applying a silicone antifouling paint.