JPS61216935A - Protection of steel structure - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a water-proof sheet due to adherence of organisms by a method in which an adhesive is applied in the air on the other surface of a water-proof sheet having a copper or its alloy foil on its one surface, the coated face is contacted with the surface of a steel structure under water, and the sheet is stretched and adhered by magnetic forces. CONSTITUTION:A water-proof sheet, e.g., of chlorosulfonated polyethylene, etc., is mixed with magnetic fine particles, e.g., of ferrite, etc., and a copper or its alloy foil is bonded through an adhesive of epoxy resin, etc., to one surface of the sheet. A water-curable adhesive of epoxy resin, etc., is applied in the air on the other surface of the sheet. The adhesive coated side of the sheet is contacted with the surface of wet surface above the water surface of the steel structure under water, and the sheet is stretched and wholly bonded to the surface of the steel structure by magnetic forces.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for protecting the surface of underwater steel structures in the ocean, rivers, etc., by using a sheet, and preventing the sheet from adhering to water and marine organisms. It is something.

(Prior Art) In structures used in oceans or rivers, such as steel sheet piles or crosspieces [+1 piles], long-term corrosion protection, especially in underwater or splash zone areas, is extremely important, needless to say.

For this reason, methods for using various materials or construction methods have been proposed, such as applying underwater anti-corrosion paint to such structures, or composite anti-corrosion methods using underwater adhesives and various sheets. There is.

However, when applying an adhesive to a wet surface such as underwater or a splash zone, or when applying adhesive to a sheet, etc., the initial adhesion of the adhesive used is poor due to the influence of water, seawater, etc. Due to mechanical obstacles such as waves and water flow, the sheet etc. may shift, peel off, or be washed away before its function is fully demonstrated, and therefore, sufficient effects cannot be expected.

By the way, in order to solve the various problems mentioned above, one of the inventors of the present invention previously developed a method in which a waterproof sheet coated with an adhesive was stretched and crimped onto the surface of an underwater steel structure, and the sheet was attached using magnetic force. We proposed a protection method that consists of

However, even with this method, underwater or marine organisms may adhere to the surface of the waterproof sheet in the underwater part of an underwater steel structure or in areas where the water level changes due to the ebb and flow of the tide depending on the day and time. There were some problems in that the waterproof sheet would become wedged in and eventually be damaged, and as a result, sufficient anti-corrosion function could not be expected for a long period of time.

(Problems to be Solved by the Invention) The present invention is useful not only for preventing corrosion on the surface of underwater steel structures in the ocean or rivers, but also for sheeting underwater or underwater in underwater parts or near the water surface (i.e., tidal areas). The aim is to provide a method of protecting steel structures, which prevents deterioration due to biofouling.

(Means for Solving the Problems) The object of the present invention is to apply an adhesive in air to the other side of a waterproof sheet with copper foil or copper alloy foil pasted on one side, and then immerse it in water. The adhesive-applied surface is brought into contact with the surface of the underwater steel structure or a wet surface above the water surface, and the waterproof sheet is spread over the surface of the underwater steel structure, and the sheet is held in place by magnetic force. This is achieved by attaching it to the surface.

The present invention will be explained in more detail below.

First, the "waterproof sheet" used in the method of the present invention includes, for example, chlorosulfonated polyethylene, polyisobutylene, chlorinated polyethylene, natural rubber, styrene rubber,
Flexible rubber sheets or plastic sheets such as butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, acrylic rubber, ethylene propylene rubber, urethane rubber, silicone rubber, fluororubber, etc. are used.

Its thickness is not particularly limited. but preferably 0.0
5-10. Make it about ff++++. Further, the shape thereof is not particularly limited, and may be continuous or tile-like.

In the method of the present invention, the "waterproof sheet" is attached to the surface of a steel structure by magnetic force. As described below, methods include making the waterproof sheet itself magnetic and attaching it to the steel structure using its own magnetic force, or attaching the waterproof sheet and then pressing it with a permanent magnet. take measures.

In the former case, that is, to impart magnetism to the waterproof sheet, magnetic particles such as ferrite represented by the general formula MO·(FezOs)n are mixed into the waterproof sheet.

In the general formula, M represents a divalent metal or lead, and n
is a constant integer value. A specific example is Ba0/6Fe
2o3, SrO・6Fe203, PbO-6Fe, Os
, CaO'2FetO, and the like.

The magnetic fine particles have an average particle diameter of about 0.1 to 20
It is about 30 to 10 μm in diameter in the waterproof sheet.
The content is about 95% by weight.

In the present invention, a flexible magnetic waterproof sheet can be obtained by magnetizing and forming a sheet using the above-mentioned materials in a conventional manner.

In the present invention, the waterproof sheet further has a metal foil on one side. As the metal foil, at least one type of metal foil selected from copper or copper alloy is used.

The steel or copper alloy foil has a thickness of 0.5μ to 1000μ
It is a thin sheet on the order of μm, and when considering adhesion and on-site construction of the waterproof sheet, it is preferably 50 to 20 μm.
A thickness of approximately 0 μm is preferable.

These are made of ordinary copper or an alloy of copper and a metal such as nickel, zinc, aluminum, silicon, or manganese, and are used in the form of a thin sheet by a conventional method.

The steel or copper alloy foil is made into the waterproof sheet of the present invention by, for example, laminating it on one side of the waterproof sheet via a suitable adhesive (epoxy resin, polyurethane resin, acrylic resin, etc.). be able to.

In the method of the present invention, an adhesive is applied to the other surface of the waterproof sheet obtained as described above, on which the coating is not formed. It is preferable to use underwater curable adhesives such as epoxy resin, urethane resin, polyester resin, and acrylic resin.

As described above, a diver, for example, brings a waterproof sheet coated with adhesive in the air into the water and adheres it to the surface of an underwater steel structure, or to a surface near or slightly above the water surface.

When adhering, the outer surface of the waterproof sheet (the surface to which no adhesive is applied) is stretched (spread) along the surface by hand or the like. By doing so, water between the structure surface and the adhesive is eliminated and the adhesive becomes "incipient adhesive."

At that time, by imparting magnetism to the waterproof sheet, it is completely attached to the surface of the steel structure. As another option B, if the waterproof sheet itself has no magnetism, a permanent magnet is used to press the outer surface of the waterproof sheet and the magnetic force is used to attach it to the surface of the steel structure.

After the initial adhesion is performed, the waterproof sheet is fixed to the structure surface by the adhesive over time. Incidentally, when the waterproof sheet itself has magnetic force, the fixing effect is further improved by the magnetic force.

Thus, according to the method of the present invention, the waterproof sheet will not shift, peel off, or be washed away due to external disturbances such as waves or water flow until the adhesive used is completely cured and exhibits its function. Furthermore, as is clear from the structure of the waterproof sheet described above, it is possible to exhibit a sufficient anticorrosive effect and to prevent deterioration of the waterproof sheet due to adhesion of underwater and marine organisms. Therefore, it is possible to protect steel structures for a long period of time.

Furthermore, when the method of the present invention is applied to, for example, steel shelves or supports of underwater fish pens or fish and shellfish farms, it is also effective in preventing diseases of fish and shellfish due to the inherent bactericidal action of copper or copper alloys. Be expected.

Hereinafter, the details of the present invention will be explained in more detail with reference to Examples.

Note that "part" or "%" is expressed as "part by weight" or "% by weight."

Example 1 An epoxy resin adhesive was applied on one side of a 1-inch-thick magnetic sheet obtained by kneading 90% barium ferrite with a particle size of 1 to 5 μm and 10% polyethylene chloride and forming it into a sheet using a conventional method. After coating, a 50 μm thick copper foil was laminated to obtain a waterproof sheet. Then, an anticorrosive underwater adhesive (epoxy resin type) was applied to the other side of the sheet. Next, this was wrapped around the steel piers of the pier, the splash/tidal area, and the underwater area, which had been prepared by water sandblasting. At that time, sufficient pressure was applied by hand to eliminate air bubbles and seawater between the substrate and adhesive. This was left to stand and tests and observations were made after 12 months.

The results are shown in Table 1.

Example 2 After applying an epoxy resin adhesive to one side of the same magnetic sheet as in Example 1, a 100 μm thick copper alloy (
A waterproof sheet was obtained by laminating copper-nickel) foil.

Then, construction was carried out in the same manner as in Example 1, and the test and observation results after 12 months are shown in Table 1.

Example 3 A waterproof sheet was prepared in the same manner as in Example 1 except that a 200 μm thick copper foil was used as the metal foil laminate material.
Construction was carried out, and tests and observations were made within 12 months.

The results are shown in Table 1.

Comparative example Non-magnetic general rubber sheet (thickness 0.6ncm)
The work was carried out in the same manner as in Example I except that copper or copper alloy foil was not laminated on the surface.

The test and observation results after 12 months are shown in Table 1.

From the above comparative test results table, it is clear that according to the method of the present invention, damage to the magnetic sheet due to adhesion of underwater or marine organisms can be prevented. It is also clear that as a result, it is possible to protect underwater steel structures for a longer period of time.

Claims (2)

[Claims] (1) Apply adhesive in the air to the other side of a waterproof sheet with copper foil or copper alloy foil pasted on one side, and then apply the adhesive applied side to the surface of the underwater steel structure. Or, a method for protecting a steel structure, which comprises bringing the waterproof sheet into contact with a wet surface above the water surface, extending the waterproof sheet over the surface of the underwater steel structure, and attaching the sheet to the surface by magnetic force. (2) The method for protecting a steel structure according to claim (1), wherein the waterproof sheet contains magnetic particles.