JPH0832850B2 - Anticorrosion construction method for underwater steel structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for anticorrosion construction of an underwater steel structure constructed in a ship or underwater.

[Conventional technology]

In recent years, oil drilling rigs or oil storage purges associated with ocean development, steel structures such as offshore plants, ships, steel structures such as steel sheet piles used for revetment work, piers of huge bridges constructed at sea, The construction and construction of underwater structures at sea ports are increasing, but it is almost impossible to move these steel structures from the installation area for maintenance. Therefore, problems such as anti-corrosion coating, cleaning, and maintenance occur in the underwater portion or splash zone portion of these marine steel structures, and the necessity of maintenance at sea has become a serious problem.

Therefore, if there is a coating method capable of coating in water as efficiently as on land and providing a coating film with excellent anticorrosion properties, its merits are great.

Conventionally, when painting a submerged part or a splash zone part of a ship or an underwater steel structure, a second-class keren that scrapes off floating rust etc. as a base treatment, and for further cleaning,
Spray a high-speed water stream to remove rust and scale,
In order to remove rust and scale better, there is a method such as mixing sand etc. in a high-speed water stream and spraying it on the steel surface (water sandblasting). It is generally performed by using such as.

Further, as a conventionally known underwater coating composition, based on an epoxy resin or a polyester resin, using a polyamine or polyamidoamine as a curing agent,
There is a composition to which a filler is added. However, this known underwater coating composition has a very weak adhesive force and very easily runs off due to waves during curing, and even if it is cured, the adhesiveness of the cured product is insufficient and long-term anticorrosion does not occur at all. It couldn't be expected.

[Problems to be solved by the invention]

The problem to be solved by the present invention is to solve the above-mentioned difficulties of conventional underwater coating compositions, and more specifically, it can be easily coated in water by the same operation as on land. An object of the present invention is to develop a composition for underwater coating capable of forming a coating having excellent adhesion and high anticorrosion property, and to provide a method capable of effectively protecting an underwater steel structure using this composition.

[Means for solving problems]

This problem is (a) a bisphenol type epoxy resin having an average of 1.7 or more epoxy groups per molecule and an epoxy equivalent (weight) of about 70 to 1000, (b) a curing agent for an epoxy resin (c) The solution is to protect the underwater steel structure with a composition based on a silane coupling agent.

[Function and Configuration of the Invention]

In the present invention, the above-mentioned specific bisphenol type epoxy resin (a) and its curing agent (b) are further coated with a composition in which a silane coupling agent (c) is blended, in other words, In particular, by adding a silane coupling agent, remarkably excellent adhesion in water is developed,
It does not run off due to waves before curing, and it cures as it is, and the cured coating improves the water resistance of the coating because the bonding force between the resin and filler is increased by the silane coupling agent. To do. Moreover, since the silane coupling agent strongly interacts with the steel substrate, it has excellent corrosion resistance and firmly adheres to the underwater steel structure. As described above, according to the anticorrosion construction method of the present invention, the underwater steel structure is effectively protected by the extremely excellent anticorrosion effect. The composition according to the present invention exhibits the same effect even in the atmosphere.

In the present invention, a bisphenol type epoxy resin having an average of about 1.7 or more epoxy groups per molecule and an epoxy equivalent (weight) of 70 to 1000 is used as the epoxy resin. What is bisphenol type epoxy resin?
Another name is glycidyl ether resin, which is a diglycidyl ether of bisphenol represented by the following formula.

(In the formula, R is a divalent radical containing at least one atom 1 to 8 atoms selected from the group consisting of C, O, S and N, preferably an alkylene or alkylidene group having 1 to 8 carbon atoms, and more preferably Is an alkylene or alkylidene group having 1 to 6 carbon atoms.) Among the above-mentioned suitable bisphenols, methylene bisphenol, isopropylidene bisphenol, butylidene bisphenol, octylidene bisphenol, bisphenol sulfide, bisphenol sulfone, bisphenol ether, Bisphenolamine and the like. In particular, excellent results are obtained with isopropylidene bisphenol.

Further suitable diglycidyl ethers are diglycidyl ethers of isopropylidene bisphenol represented by the following formula.

In the present invention, the bisphenol type epoxy resin is required to have an average of 1.7 or more, preferably 1.7 to 2.3 epoxy groups per molecule.
If the number is less than the above, sufficient adhesive strength in water will not be exhibited. Also as an epoxy equivalent 70-1000, preferably 70-
A product having a range of 500 is used, and a cured product having excellent mechanical strength cannot be obtained outside the range.

As the epoxy resin curing agent used in the present invention, all of the usual water-curable curing agents for epoxy resins can be used. For example, aliphatic polyamine, aromatic modified polyamine, aliphatic modified polyamine, alicyclic Group polyamines, alicyclic modified polyamines, polyamides, amino resins, polyamidoamines, carboxylic acids and the like.

The use ratio of the curing agent is usually 0.5 to 2 equivalents of active amine hydrogen groups to 1 equivalent of epoxy groups.

As a preferable curing agent, an aromatic modified polyamine,
These are aliphatic modified polyamines and alicyclic modified polyamines.

The silane coupling agent used in the present invention,
The following formula is used.

R'Si (OR) ₃ wherein R'represents an organic functional group such as an amino group, a mercapto group, a vinyl group or an epoxy group, and OR represents a functional group such as an alkoxy group. For example, vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylacetosilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltris (β-methoxyethoxysilane). , Β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ
-Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β-
(Aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane , Bis (trimethylsilano) amine,
N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
Examples include chloropropyltrimethoxysilane and the like. Particularly, aminosilane-based, mercaptosilane-based, and epoxysilane-based silane coupling agents are preferable, and more specifically, γ-glycidoxypropyltrimethoxysilane, N
Examples include -β- (aminoethyl) γ-aminopropyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane.

The compounding ratio of the silane coupling agent to the total amount of the epoxy resin and the curing agent is 0.05 to 5% (weight) of the total amount of the epoxy resin and the curing agent, and more preferably 0.1 to 2% (weight).

When the blending ratio of the silane coupling agent is less than 0.05%, the effect of the silane coupling agent cannot be exhibited, and the adhesiveness and anticorrosiveness are not improved. Further, if the blending ratio exceeds 5%, the mechanical properties of the cured product are adversely affected, which is not preferable.

Furthermore, the composition according to the anticorrosion construction method of the present invention, if necessary, other epoxy resin, diluent, solvent, color pigment,
Anti-rust pigment, filler, and other additives can be used together.

In this case, other epoxy resin used as needed is other than the above-mentioned epoxy resin used in the present invention, and examples thereof include bisphenol A.diglycidyl ether having an epoxy equivalent of 1000 or more. These other epoxy resins are usually used in an amount of 10 parts or less, preferably 0 to 5, with respect to 100 parts by weight of the epoxy resin (a). Examples of the filler include coal tar, glass fiber, glass flakes, asbestos, quartz powder, mineral silicates such as mica, slate powder, kaolin, aluminum oxide trihydrate, aluminum hydroxide, calcium carbonate and bentonite. , Talc, titanium dioxide, iron oxide, or metal powders such as zinc, magnesium, and aluminum, and any of these can be effectively used depending on the application. Furthermore, it is also effective to use those fillers whose surface is previously treated with the silane coupling agent.

〔The invention's effect〕

In the present invention, since the underwater steel structure can be extremely effectively subjected to anticorrosion construction, the period of use of these structures is greatly extended, which is extremely industrially effective.

〔Example〕

The present invention will be specifically described below with reference to examples. However, in the following examples, “part” means “part by weight”.

Example 1 100 parts of bisphenol A / diglycidyl ether (epoxy equivalent = 260), 40 parts of calcium carbonate, 1 part of colloidal silica, 0.5 part of γ-glycidoxypropyltrimethoxysilane were mixed at 50 ° C. in a stirring mixer. , An epoxy resin compounding system.

On the other hand, 100 parts of aromatic polyamine (amine value 270, aromatic: diaminodiphenylmethane), calcium carbonate 40
Parts and 2 parts of colloidal silica were mixed at 50 ° C. in a stirring and mixing pot to prepare a curing agent compounding system.

The curing agent blending system and the epoxy resin blending system described above were mixed at a mixing ratio (weight ratio) of 2: 3 to obtain a two-pack type water-curable epoxy resin composition.

Using this composition, a steel plate was coated with a rubber spatula so as to have a dry film thickness of 300 μm, and the initial adhesion, the adhesion after curing, the fracture rate and the occurrence of rust were measured. The results are shown in Table 1 below. However, the steel sheet used was a steel sheet immediately immersed in 3% saline for 1 day immediately after shot blasting.

Example 2 100 parts of bisphenol A / diglycidyl ether (epoxy equivalent 260), 40 parts of calcium carbonate and 1 part of colloidal silica were mixed at 50 ° C. in a stirring and mixing pot to prepare an epoxy resin compounding system.

On the other hand, 100 parts of aromatic modified polyamine (amine value: 270, aromatic: diaminodiphenylmethane), 40 parts of calcium carbonate, 1 part of N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane are mixed in a stirring mixer at 50 ° C. And mixed to prepare a curing agent blending system. A two-component underwater curable epoxy resin composition was prepared by mixing the curing agent compounding system and the epoxy resin compounding system in a mixing ratio (weight ratio) of 2: 3, and treated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 100 parts of aromatic modified polyamine (amine value: 270, aromatic diaminodiphenylmethane), 40 parts of calcium carbonate, 2 parts of colloidal silica, 1 part of γ-mercaptopropyltrimethoxysilane are mixed at 50 ° C. in a stirring and mixing pot and cured. It was a compounding system.

A two-component underwater curable epoxy resin composition was prepared by setting the mixing ratio (weight ratio) of this curing agent compounding system and the same epoxy resin compounding system as in Example 2 to 2: 3, and in the same manner as in Example 1. Processed.

 The results are shown in Table 1.

Comparative Example 1 100 parts of bisphenol A / diglycidyl ether (epoxy equivalent 260), 40 parts of calcium carbonate and 1 part of colloidal silica were mixed at 50 ° C. in a stirring and mixing pot to prepare an epoxy resin compounding system.

On the other hand, 100 parts of aromatic modified polyamine (amine value 270, aromatic diaminodiphenylmethane), calcium carbonate 40
Part, 2 parts of colloidal silica are mixed in a stirring and mixing pot at 50 ° C.,
It was a curing agent compounding system.

A two-pack type water-curable epoxy resin composition was prepared by mixing the curing agent-containing system and the epoxy resin-containing system at a mixing ratio (weight ratio) of 2: 3, and treated in the same manner as in Example 1.
The results are shown in Table 1.

Comparative Example 2 The procedure of Example 1 was repeated except that polysilicate (trade name: ethyl silicate 40 manufactured by Colcoat Co., Ltd.) was used in place of α-glycidoxypropyltrimethoxysilane in Example 1 described above. The results are shown in Table 1.

Comparative Example 3 Instead of the bisphenol A.diglycidyl ether used in Example 1 above, 30 parts of polyglycidyl amine (epoxy resin, epoxy equivalent 120), polyhydric alcohol polyglycidyl ether (epoxy resin, epoxy equivalent 320) 7
0 parts, 70 parts of calcium carbonate, 1 part of colloidal silica, γ-glycidoxypropyltrimethoxysilane
0.5 part was mixed at 50 ° C. in a stirring and mixing pot to prepare an epoxy resin compounding system.

On the other hand, the curing agent compounding system used in Example 1 was used, and the weight compounding ratio of the curing agent compounding system and the epoxy resin compounding system was set to 2: 3 to prepare an underwater curable epoxy resin composition. The same treatment was carried out, and the results are shown in Table 1.

However, the measuring methods of each physical property in Table 1 are as follows.

Steel plate: 6 × 300 × 300 mm hot rolled steel plate Coating method: After dipping the above steel plate for a predetermined time, the composition was applied with a rubber spatula and cured in the state of being immersed.

Initial adhesion: The workability (adhesion) when applying with a rubber spatula was observed, and the following evaluation was performed.

○ ・ ・ ・ Good (attached only by applying a rubber spatula) × ・ ・ ・ Poor (not attached) Adhesion after curing: After 6 months, the coated sample was taken out in the atmosphere (23 ℃, 65% RH), After one day, cut the coating film with a cutter and glue the measuring dolly with an adhesive,
The adhesion was measured with an adhesion tester.

Cohesive failure rate: A polyethylene film having a uniform thickness was placed on the measurement site, the coating film part that had undergone cohesive failure was transferred with a marker, and the weight was measured to calculate the cohesive failure rate by the following formula.

However, m indicates the entire measurement site, and m ₁ indicates the part where cohesive failure occurs.

Occurrence of rust: The surface was observed with the naked eye and examined for its presence.

As is clear from Table 1 above, even if an organic silicate other than the silane coupling agent is used as the specific epoxy resin and curing agent used in the present invention (Comparative Example 2), or even if the silane coupling agent is used. However, when an epoxy resin other than the specific epoxy resin used in the present invention and a curing agent are used (Comparative Example 3), the underwater coating properties are remarkably low.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masato Shimizu 1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Electric Industry Co., Ltd. (56) Reference JP-A-53-28632 (JP, A) JP JP-A-60-221419 (JP, A) JP-A-57-127479 (JP, A) JP-A-57-179254 (JP, A) JP-A-59-123574 (JP, A)

Claims (2)

[Claims] (A) An average of 1.7 or more epoxy groups per molecule, and an epoxy group equivalent (weight) of about 70-.
A bisphenol type epoxy resin which is 1000 (b) a curing agent for an underwater curable epoxy resin, and (c) a silane coupling agent. A method for anticorrosion construction of a steel structure, which comprises coating an underwater steel structure. 2. The anticorrosion construction method according to claim 1, wherein the silane coupling agent is an epoxy type silane coupling agent.