JP2871767B2 - Underwater coating type paint composition and method for underwater coating of this composition - Google Patents

Description

The present invention relates to an underwater coating composition comprising a thermosetting underwater coating resin composition used for forming an adhesive or protective coating layer in water or in a wet state. And a method of applying the coating composition underwater.

(Prior Art) Many steel structures and concrete structures are constructed in the sea, on the beach, in rivers, lakes, and the like, and they are constantly exposed to severe corrosive environments. These structures, such as steel sheet pile revetments, steel pipe piles for port facilities, piers, dam gates, floodgates, etc., require maintenance.

These anticorrosion coating methods in water, that is, underwater coating methods, are known in which the surrounding area is damped and drained, but this method is very expensive. For this reason, underwater coating-type anticorrosion materials based on polyamide-cured epoxy resin, modified amine-cured epoxy resin, unsaturated polyester resin, etc., which can reduce the work cost without damaging the surrounding area and lowering the work cost, have been put into practical use. I have.

(Problems to be Solved by the Invention) However, the underwater coating type paint based on each of the above resins has a drawback of insufficient adhesion to steel or concrete surfaces in water, in the sea, or on wet surfaces.

Conventional underwater hardening paints, the iron surface washed by means such as disk sander, sand blast, etc. is placed in water, seawater or wet, and due to aging, it becomes an invisible rusting state again, underwater or Due to the adhesion of marine microorganisms, etc., especially in natural seawater, the adhesion is 20-30 kg / c
In m ² approximately, in some places it was observed when Pasi also be a 10 kg / cm ² or less. This is considered to be due to variation in the time from reprocessing to coating.

Accordingly, an object of the present invention is to provide an underwater coating composed of an underwater curable resin composition having excellent adhesion when the resin composition is applied to a water, sea, or wet surface with a brush, a rubber spatula, a trowel, a roller, or the like. SUMMARY OF THE INVENTION It is an object of the present invention to provide a mold coating composition and a method of applying the composition underwater.

(Means for Solving the Problems) The feature of the underwater coating type coating composition according to the present invention is (a)
Excellent in water applicability formed by kneading an epoxy resin having curability in water, (b) a curing agent, and (c) a heterocyclic compound containing a nitrogen atom, and having excellent adhesion of the coating film and the underwater coating film And a water-insoluble and non-aqueous underwater coating type resin composition having excellent residual properties.

The characteristics of the underwater coating method of the underwater coating type coating composition according to the present invention include (a) an epoxy resin having curability in water, (b) a curing agent, and (c) a nitrogen-containing heterocyclic compound. A water-insoluble and non-aqueous underwater coating type resin composition excellent in underwater coating properties formed by kneading the compound, and excellent in adherence of the coating film and excellent in the persistence of the underwater coating film, is used for coating the object to be coated in water. After applying to the surface, it is to be cured in water.

First, the resin serving as a base of the resin composition of the present invention has the effect of the present invention as long as it has curability in water and can exert good adhesion by being applied in a dry state in a clean state. , But epoxy resin is mainly used.

In the case of an epoxy resin, the epoxy resin for the main material contains at least one epoxy group in one molecule,
A liquid at room temperature with an epoxy equivalent of 70 to 1000 is preferable, and examples thereof include glycidyl ethers of phenol compounds and polyol compounds, and glycidyl esters of polycarboxylic acids such as adipic acid, phthalic acid, and dimer acid.

As a curing agent for the epoxy resin, aliphatic amines, alicyclic amines, aromatic amines, or amide modifications thereof, adduct modifications, Mannich reaction modifications, Michael reaction modifications, carbonyl modifications, These mixtures are used as needed.

Examples of the nitrogen-containing heterocyclic compound used in the present invention include isoquinoline, carbazole, benzotriazole, pyridine, benzimidazole, quinoxaline, cinnoline, 7-azaindole, phenazine, indazole and compounds having these skeletal structures. At least one selected from the group can be mentioned.

Compounds having a skeletal structure include α-aminopyridine, 2- (2-hydroxyethyl) pyridine, 2-amino-
5-bromopyridine, 2-acetylpyridine, 3-acetoxypyridine, 2-bromo-5-methylpyridine, 2-amino-3,5-dibromopyridine, 2-butoxypyridine, 2-chloro-6-methylpyridine, 2 , 4-dimethylpyridine, 2-
Methoxypyridine, 2-ethylpyridine, 2-fluoropyridine, ethylnicotinate, ethylisonicotinate,
N, N-diethylnicotinamide, N- (P-diethylaminoethyl) iso-nicotinamide, 4-ter-butylpyridine, 2-cyanopyridine, 3,5-dichloro-2,4,6-trifluoropyridine, 5 -Butylpyridine-2-carboxylic acid, 3
-Chloro-2,4,5.6-tetrafluoropyridine, 2-bromopyridine, 2,5-dibromopyridine, 2-hydroxy-5
-Methylpyridine-3-carboxylic acid, 2-dimethylaminopyridine, 2-hydroxy-5-methylpyridine, 2,6-dimethoxypyridine, 2,3-cyclopentenopyridine, 2,3-
Cycloheptenopyridine, 2,3-cyclohexenopyridine, 2-methylquinoxaline, 2,3-dichloroquinoxaline, 2-aminobenzimidazole, 2-amino-5,6-dimethylpenzimidazole, 5,6-dimethylbenz Imidazole, 1-ethyl-2-methylbenzimidazole, 2,
5,6-trimethylbenzimidazole, 5-methyl-benzimidazole, 2-methylmercaptomethylbenzimidazole, IH-benzotriazole, benzotriazole, hydroxyethylbenzotriazole, benzotriazole-1-succinic acid, 1- ( 2,3-dihydroxypropyl) benzotriazole, 1- [NN-bis- (2-ethylhexyl) aminomethyl] benzotriazole, benzotriazole-1-methylenephosphinic acid, benzotriazole-1-methylenephosphonic acid, etc. Can be shown.

If the nitrogen-containing heterocyclic compound is contained in an amount of 0.2 part or more per 100 parts by weight of the resin composition, the effects of the present invention can be exhibited. There is no particular upper limit on the amount of the compound, but as is well known, there are those with a unique odor, those that impair water resistance and physical properties, and those that are frequently used may cause problems.
A range of 10 parts is appropriate.

As described above, the underwater coating type resin composition according to the present invention is excellent in adhesion to a substrate in water having no solvent and being non-aqueous and non-aqueous, and having excellent persistence of an underwater coating. is there.

Other components of the resin composition of the present invention include talc, mica, clay, kaolin, barium sulfate, calcium carbonate, alumina. Extender pigments such as zinc white, silica powder, titanium white, graphite, petals, yellow iron oxide, organic red, organic yellow, organic blue, organic green, etc. coloring pigments, chromic acid type, molybdic acid type, phosphoric acid type Anticorrosive dyes, such as boric acid, ferrite, and lead acid, metal powders such as stainless steel powder, zinc dust, and aluminum powder;
Glass flakes, stainless flakes, aluminum flakes, scaly pigments such as plastic frames, asbestos / vegetable fibers, glass fibers, carbon fibers, fiber materials such as synthetic fibers, silane coupling agents, anti-settling / sagging agents, etc. Additives and the like can be appropriately selected to adjust desired hue, viscosity suitable for coating, and the like.

(Action) The mechanism by which the nitrogen-containing heterocyclic compound improves the adhesion is not well understood, but is presumed as follows. That is, it is known that unpaired electrons (loan pairs) of a nitrogen atom are coordinated to a metal, and it is considered that the heterocyclic compound is oriented by substituting water covering the metal surface.
On the other hand, since the heterocyclic compound has a water blocking portion composed of a hydrocarbon structure, it is considered that water is pushed farther than the metal surface, and instead, the resin component can approach the metal surface and exert adhesive force. You.

(Effect of the Invention) The underwater coatable resin composition according to the present invention has excellent water applicability, and is water-insoluble and non-aqueous with excellent adhesion of the coating film and excellent persistence of the underwater coating film. The improvement in adhesion to a wet metal surface is remarkable, and is comparable to the adhesion to a dry metal surface, and can exhibit an anticorrosive effect or an adhesive effect over a long period of time. it can.

(Examples) Examples of the present invention will be described below.

Examples 1 to 6, Comparative Examples 1 and 2 Epoxy resin (manufactured by Shell Chemical Co., trade name: Epicoat 82)
8. Modified polyamine (made by Asahi Denka, trade name: Adeka Hardener EH-) with bisphenol A type epoxy resin as the main ingredient
229) is a common base compounding system using as a curing agent.
1 was obtained. (The compounding amount is shown in parts by weight.) The mixing and kneading method, the preparation of the paint, the test method and the evaluation method are as follows.

Mixing and kneading method: Three rolls Coating preparation: Immediately before use, mix the proportions indicated by the small amounts of each component thoroughly before use.

Test method: A mild steel plate subjected to sand blasting of 70 × 150 × 2.3 mm was immersed in the sea for 30 minutes, and adjusted to a state where returned rust, marine bacteria and the like adhered to the painted surface. Next, the resin composition prepared in the above-described manner was applied to the above-mentioned iron plate fixed vertically by using a rubber roller in sea water, and cured and cured in sea water for 7 days to be used for measurement of adhesion strength.

However, Comparative Example-2 was obtained by curing the resin composition used in Comparative Example-1 in the air.

(Evaluation method) The average value obtained by bonding a jig to the surface with an epoxy resin-based adhesive using an adhesion tester (manufactured by Elkometer) and measuring the adhesion at three points on the test plate surface is shown.

In addition, the residual ratio of the coating film after the measurement of the adhesion was visually determined.

Comparative Example 1 is a base epoxy resin composition, but both in-water paintability and adhesion are poor and cannot be practically used.

Examples -1 to 6 were all significantly improved in adhesion as compared with Comparative Example 1, and obtained results comparable to Comparative Example 2 in which the coating was performed in the air.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tatsuhiro Tanaka 1-15-2 Yoshishima Higashi, Naka-ku, Hiroshima City, Hiroshima Pref. China Paint Co., Ltd. (56) References JP-A-63-10674 (JP, A) JP-A-52-18799 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09D 5/14-5/16 C09D 7/12

Claims (2)

(57) [Claims] 1. An epoxy resin having curability in water, (b) a curing agent, and (c) isoquinoline, carbazole, benzotriazole, pyridine, benzimidazole, quinoxaline, cinnoline, 7-azaindole, and phenazine. , Indazole and at least one nitrogen-containing heterocyclic compound selected from the group consisting of compounds having a skeletal structure thereof are kneaded with, and have excellent coatability in water, An underwater coating composition comprising a water-insoluble and nonaqueous underwater coating resin composition having excellent coating film persistence. 2. An epoxy resin having curability in water, (b) a curing agent, and (c) isoquinoline, carbazole, benzotriazole, pyridine, benzimidazole, quinoxaline, cinnoline, 7-azaindole, and phenazine. , Indazole and at least one nitrogen-containing heterocyclic compound selected from the group consisting of compounds having a skeletal structure thereof are kneaded with, and have excellent coatability in water, An underwater coating composition comprising a water-insoluble and non-aqueous underwater coating resin composition having excellent residual properties of the coating film,
An underwater coating method, wherein the method is applied to the surface of an object to be coated in water and then cured in water.