JPS5876465A - Corrosion proof covering material - Google Patents

Abstract

PURPOSE:To obtain titled material of excellent corrosion resistance and workability, suitable for corrosionproof repair of steel structure in water under pressurized state, by impregnating a reticulate continuous base material comprising, e.g., zinc with a two-pack epoxy resin composition consisting mainly of an epoxy resin and a water-curable curing agent. CONSTITUTION:The objective covering material can be obtained by inpregnating a two-pack epoxy resin composition comprising, for example, (A) a mixed resin consisting of (i) an epoxy resin (e.g., a phenolic epoxy resin) and (ii) another resin compatible with the component (i) (e.g., a phenoxy resin) and (B) a water- curable curing agent (e.g., an aromatic amine), a filler, and, if required, a fluiding adjustor, etc. in (C) a reticulate continuous base material composed mainly of at least one sort of metal selected from zinc, aluminum, and magnesium. EFFECT:A large amount of application of filler results in a highly-viscous resin composition; for example, the use of 75wt% of zinc powder leads to higher corrosionproof effect.

Description

[Detailed Description of the Invention] The present invention has excellent corrosion resistance and workability that can be effectively used for anticorrosion repair of steel structures installed underwater or under humid conditions, especially in locations affected by water flow or water pressure. Regarding anti-corrosion coating.

As is well known, steel materials in the marine environment are subject to severe corrosion, especially near the splash zone and tidal zone.

For this reason, when constructing new port steel structures and offshore steel structures, it has become common to use heavy anti-corrosion coating, that is, an undercoat of zinc-rich primer, and then a topcoat of synthetic resin paint, or cathodic protection. There is. However, cathodic protection only works effectively in the underwater area, and is ineffective in the splash zone where corrosion is most severe. Furthermore, although heavy-duty anti-corrosion coatings using a zinc-rich primer as an undercoat exhibit fairly long-term corrosion protection, they can only be applied on land, such as in the case of new construction. Conventional zinc-rich primers are paints in which a large amount of zinc powder is combined with an inorganic binder such as alkyl silicate or alkali silicate, or an organic binder such as epoxy resin, rubber resin, or alkyd resin. It is widely used as an undercoat to prevent corrosion of steel materials through the barrier effect of zinc corrosion products, but it is impossible to apply it on wet surfaces or underwater. For this reason, when performing anti-corrosion repairs on existing steel structures, it is not possible to use zinc-rich brimers, which have excellent anti-corrosion properties, and the only way to do this is by applying a small amount of water-curing paint directly to the steel surface. Only methods are used. Moreover, this method also has the disadvantage that the paint itself peels off easily in places with fast water flow or large waves because the paint itself has poor cohesive strength and poor adhesion to the steel surface.

The present invention was developed as a result of intensive study to eliminate the drawbacks of conventional construction methods as described above, with the aim of anti-corrosion repair of harbor steel structures and marine steel structures, particularly those extending from underwater to the splash zone. The object of the present invention is to provide a new and useful anti-corrosion coating that can be easily carried out and allows the applied paint to exhibit a sufficient anti-corrosion function.

That is, the present invention provides a compound system mainly composed of an epoxy resin or a mixed resin consisting of an epoxy resin and another resin compatible with the epoxy resin, and a curing agent containing an underwater curing agent that cures the epoxy resin even in water. A two-component epoxy resin composition consisting of a compounding system mainly composed of zinc, aluminum, and magnesium, or a composition further containing 75% by weight or less of zinc powder. This is an anticorrosive coating formed by impregnating a continuous network base material having a surface layer as a component.

The present invention will be explained in detail below. FIG. 1 is a sectional view showing the state when a copper body is coated with the anti-corrosion coating of the present invention.
2 indicates a two-component epoxy resin composition or a two-component epoxy resin composition entirely containing zinc powder, 2 indicates a continuous mesh base material, and 3 indicates a copper body as an object to be protected from corrosion.

Of the two compounding systems constituting the two-component epoxy resin composition of the present invention, one is mainly composed of an epoxy resin or a mixed resin consisting of an epoxy resin and another resin that is compatible with the epoxy resin, Known additives such as fillers and other fluidity modifiers are added to this as other components depending on the purpose of use. These other components are main component 1
It is usually blended at a ratio of 1 to 100 parts by weight per 100 parts by weight, and by using a large amount of filler, it is possible to obtain a blended system with a relatively high viscosity.

As the epoxy resin, bisphenol type epoxy resin is suitable, but other types include: aliphatic epoxy resin, phenol or cresol novolac type epoxy resin, phthalate glycidyl ester type epoxy resin, β-methylepichlorohydrin type epoxy resin, and dimer acid type epoxy resin. Examples include resins, polyglycol type epoxy resins, and the like. These epoxy resins may be used alone or in combination of two or more.

In addition, other resins that are compatible with the above epoxy resin include thermosetting resins and thermoplastic resins. Typical thermosetting resins include phenoxy resin, phenolic resin, xylene resin, etc. Examples of the plastic resin include polyester resin, ethylene-vinyl acetate copolymer, thiocol resin, ionomer resin, modified butadiene-acrylonitrile resin, vinyl acetate resin, coal such as coal tar and asphalt pitch, petroleum residue resin, etc. can. One or more of these resins are used together with the above-mentioned epoxy resin.

Another compounding system in the present invention is one in which the epoxy resin is mainly composed of a curing agent including an underwater curing agent that can be cured even in water, and other ingredients include fillers and other fluidity adjustment agents. Known additives such as additives are blended depending on the purpose of use.

These other components are usually blended at a ratio of 1 to 1000 parts by weight per 100 parts by weight of the main component, and by using a large amount of filler, it is possible to create a blended system with a relatively high viscosity. can.

As the underwater curing agent, use one or more curing agents for epoxy resins, such as aromatic amines, polyalkylene polyamines, polyamides, amine-modified amides, and ketimines, which are poorly soluble in water and have the ability to replace water molecules. do. A normal room temperature curing agent can be used together with this underwater curing agent, and examples of these curing agents include aliphatic polyamines, polyamidoamines, amine-containing adducts, and separated adducts.

A two-part epoxy resin composition is constituted by a combination of a compounding system containing an epoxy resin as a main component (main ingredient) and a compounding system containing an underwater curable curing agent as a main component (curing agent). By mixing the base resin and the curing agent, the curing reaction progresses, and an epoxy resin-based cured product is obtained.

Two-component epoxy resin compositions can be mixed and applied using a wet hand method, such as those in which the main ingredient and curing agent are made into a high-viscosity formulation, or low-viscosity paint types (with a viscosity of approximately 500 poise). (below) is mixed with silica sand or asbestos just before use, and is prepared to withstand water pressure, water flow, etc.

Next, in the anticorrosive coating of the present invention, the mesh-like continuous base material improves workability due to its form-retaining function, such as preventing the two-component epoxy resin composition from falling off during construction and peeling due to water currents and waves. It is used for the purpose of reinforcing epoxy resin compositions. Furthermore, an anticorrosion effect is expected by bringing the mesh-like continuous base material into contact with the steel substrate to be coated with anticorrosion. In order to achieve these objectives, the core material of the mesh-like continuous base material must have a large number of meshes, such as metal lath, woven fabric, or non-woven fabric, and must also have a continuous shape with electrical conductivity. be. Also, one of zinc, aluminum, and magnesium has a sacrificial anode effect on iron in seawater.
It is necessary to have a surface layer on the surface of the core material containing a species or two or more species as main components.

For this purpose, the core material of the continuous mesh base material may be one of zinc, aluminum, or magnesium, or an alloy of two or more of them, or may be made of iron, glass fiber, or synthetic fiber. The surface is plated with one or more of lead, aluminum, and magnesium.
It may be coated with a coating or the like. The mesh constituting the mesh-like continuous base material is determined so that it can be easily impregnated with the two-component epoxy resin composition and has a good shape retention function.

Further, from the viewpoint of construction work, it is desirable to adjust the rigidity of the continuous mesh base material. If the rigidity is too large, it will be difficult to wrap the coating around the object to be protected, and lifting will occur between the mesh metal base material and the object to be protected, resulting in insufficient contact and loss of corrosion protection. be exposed.

Therefore, it is desirable to appropriately adjust the rigidity of the mesh-like continuous base material using a core material, etc., and also adjust the thickness of the base material. From the viewpoint of workability and form-retaining functionality, it is desirable to adjust the thickness of the mesh continuous base material to a range of 0.3 to 5 mm.

Further, for the purpose of assisting the anti-corrosion protection effect of the base material, 75% by weight or less of zinc powder may be added to the two-component epoxy resin composition. If it is added in an amount exceeding 75% by weight, the cohesive force of the epoxy resin composition itself and the adhesion to the steel substrate will be extremely reduced, so it is limited to 75% by weight or less.

The two-component epoxy resin composition may be impregnated into the base material by wrapping a mesh continuous base material around the copper body to be coated in advance, and then impregnating the two-component epoxy resin composition by a filling method. Then, the base material is pre-impregnated with a two-part epoxy resin composition,
After that, the copper body may be coated.

In addition, the anti-corrosion coating of the present invention applied to a copper body will harden over time and will provide sufficient anti-corrosion performance, but the surface may be overcoated for weather resistance or cosmetic purposes. Also good.

Next, the present invention will be explained in more detail with reference to Examples.

Example A two-part epoxy resin composition and a continuous network substrate were prepared in the following manner.

〇 Two-component epoxy resin composition Epicoat +828 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.) 85 parts and Ebicoatna 1001 (epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd.) 15 parts as main components,
Talc S (manufactured by Asahi Powder Industry Co., Ltd.) 30 was added to this as a filler.
5 parts of Crystalline) 3H (manufactured by Nagashio Sangyo Co., Ltd.), 5 parts of Calidria RG-144 (manufactured by Union Carbide Co., Ltd.), and further added 2 parts of KBM 403 (silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd.), The mixture was mixed at 80° C. in a stirring mixing pot to form a main ingredient.

Next, Sanmydna 300 (hardening agent manufactured by Tamayo Kagaku Kogyo Co., Ltd.)
40 parts and 45 parts of Sanmide φ315 (curing agent manufactured by Tamayo Kagaku Kogyo Co., Ltd.) as the main components, 8120 parts of Taruri, 3 parts of Calidria RG-144, and ◆1 carbon.
000 (pigment manufactured by Mitsubishi Kasei Corporation) was added and mixed at 60° C. in a stirring mixing pot to obtain a blended system containing a curing agent.

O mesh continuous base material Made of zinc wire with a diameter of approximately 0.5 σ, width approximately 150111I
+1 I made a belt-shaped wire mesh with an apparent thickness of about 3 cranes.

Next, we will show an example of anti-corrosion construction using the above materials.

Using steel pipe piles with a nominal capacity of 800A that were driven into the sea, corrosion protection was carried out in an area approximately 3 m wide, from approximately 1 m below the sea surface to approximately 2 m above the sea surface, and the subsequent corrosion prevention performance was observed over time. First, the entire area to be protected against corrosion was prepared using a keren rod and underwater sangu to remove living organisms and iron rust. Next, a strip of zinc-made steel with a width of about 150 mm and an apparent thickness of about 3 mm, woven from zinc wire of about Q, 5i + mσ, was tightly wrapped around a steel pipe pile, and then impregnated with a two-component epoxy resin composition by a filling method. did. The two-component epoxy resin composition is made by mixing the above-mentioned main ingredient and a compound containing a curing agent at a weight ratio of 1:1 using a wet hand method to form a putty. Then, the sea part was impregnated by the filling method by ordinary workers. The two-component epoxy resin composition was impregnated into the voids of the wire mesh and then further coated to give a total coating thickness of about 6 mm. During construction, the two-component epoxy resin composition showed no peeling or falling off, and exhibited good workability. Further, observation results after about 1.5 years showed good corrosion resistance with no abnormalities such as cracking or peeling observed.

As detailed above, the anti-corrosion coating of the present invention can be applied underwater or under humid conditions, where it is difficult to apply conventional zinc-rich brimers or underwater curing paints, to places where the influence of water flow or water pressure is large. For steel structures installed in
Corrosion-proof repair work can be carried out easily, and the desired corrosion-proofing performance can be fully demonstrated. The anti-corrosion coating of the present invention can be used extremely effectively in the anti-corrosion repair of existing steel structures, but it goes without saying that it can also be used in land-based construction such as new construction.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a copper body coated with the anticorrosive coating of the present invention. 1... Two-component epoxy resin composition, 2... Reticulated continuous base material, 3... Copper body. No. 72 Continued from page 1 0 Inventor: Shigeru Katayama, 1-1-2, Hozumi, Ibaraki City, Nitto Electric Industry Co., Ltd.Applicant: Nitto Electric Industry Co., Ltd., 1-1-2, Hozumi, Ibaraki City? “Aji” 85B-76485 (5)

Claims (3)

[Claims] (1) A compounding system mainly composed of epoxy resin or a mixed resin consisting of epoxy resin and other resins that are compatible with it, and a curing agent containing an underwater curing agent that can harden the epoxy resin even in water. Corrosion protection obtained by impregnating a two-component epoxy resin composition consisting of a compounding system as an ingredient into a continuous mesh base material having a surface layer containing one or more of zinc, aluminum, and magnesium as main components. Covering body. (2) A compound system mainly composed of an epoxy resin or a mixed resin consisting of an epoxy resin and another resin that is compatible with the epoxy resin, and a curing agent containing an underwater curing agent that can harden the epoxy resin even in water. A two-component epoxy resin composition containing 75% by weight or less of zinc powder is applied to a surface containing one or more of zinc, aluminum, and magnesium as a main component. An anti-corrosion coating formed by impregnating a mesh-like continuous base material having layers. (3) Claims (1) or (2) wherein the core material of the mesh continuous base material is metal, glass fiber, or synthetic fiber in the form of metal lath, woven fabric, or nonwoven fabric.
Anti-corrosion coating as described in section.