JPH0445617B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) 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 underwater and marine organisms. (Prior Art) In structures used in the ocean or rivers, such as steel sheet piles or pier steel piles, it goes without saying that long-term corrosion protection, especially in underwater or splash zone areas, is extremely important. 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. using an adhesive, water,
The initial adhesion of the adhesive used is poor due to the influence of seawater, etc., and mechanical obstacles such as waves and water currents may cause sheets to shift, peel, or be washed away before they can fully demonstrate their functions. Therefore, sufficient effects could not 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 tarpaulin sheet in the underwater part of the underwater steel structure or in areas where the water level changes depending on the day and time due to the ebb and flow of the tide. There were some problems in that the tarpaulin sheet could become wedged in and eventually be damaged, and as a result, it could no longer be expected to have sufficient anti-corrosion properties over 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 preventing corrosion of sheets in underwater parts or near the water surface (i.e., at low and low tides). 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-coated surface is brought into contact with the surface of the underwater steel structure or the wet surface above the water surface, and the waterproof sheet is spread on the surface of the underwater steel structure, and the inside or outside of the sheet is This is accomplished by attracting the sheet to its surface by means of permanent magnets located on the surface. The present invention will be explained in more detail below. First, the "waterproof sheet" used in the method of the present invention
Examples include chlorosulfonated polyethylene, polyisobutylene, chlorinated polyethylene, natural rubber, styrene rubber, butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, acrylic rubber, ethylene propylene rubber, urethane rubber,
A flexible rubber sheet such as silicone rubber or fluorine rubber, or a plastic sheet is used. Its thickness is not particularly limited. However, it is preferably about 0.05 to 10 mm. Further, the shape thereof is not particularly limited and may be any shape such as continuous or tiled. In the method of the present invention, "attracting (holding) the waterproof sheet to the surface of the steel structure with a permanent magnet" means that magnetic particles are mixed in the waterproof sheet in advance, and the waterproof sheet is attached to the surface of the steel structure. The sheet is held by the magnetic force acting between the magnetic particles in the tarpaulin sheet and the iron by attaching it to the surface.
Or, after attaching a waterproof sheet to the surface of a steel structure, a permanent magnet is attached to the surface of the sheet, and the waterproof sheet is held by the magnetic force acting between the iron and the magnet (until the adhesive layer begins to take effect). Afterwards, the permanent magnet may be removed if necessary.) In the former case, that is, to impart magnetism to the waterproof sheet, magnetic particles such as ferrite represented by the general formula MO.(Fe ₂ O ₃ ) _o 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
BaO・6Fe ₂ O ₃ , SrO・6Fe ₂ O ₃ , PbO・6Fe ₂ O ₃ ,
Examples include CaO・2Fe ₂ O ₃ . The magnetic fine particles have an average particle diameter of about 0.1
It has a diameter of about 20 μm, and is contained in the waterproof sheet in an amount of about 30 to 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 copper or copper alloy foil has a thickness of 0.5μ~
It is a thin sheet of about 1000 μm, and preferably about 50 to 200 μm in consideration of adhesion and on-site workability of the waterproof sheet. 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 copper or copper alloy foil is laminated onto one side of the waterproof sheet using, for example, a suitable adhesive (epoxy resin, polyurethane resin, acrylic resin, etc.) to form the waterproof sheet of the present invention. 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 an 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 making the waterproof sheet magnetic, it can be completely attached to the surface of the steel structure. Alternatively, if the waterproof sheet itself does not have magnetism, a permanent magnet presses the outer surface of the waterproof sheet and the waterproof sheet is attracted to the surface of the steel structure by magnetic force. After the initial adhesion is performed, the waterproof sheet is fixed to the surface of the structure by an 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. As is clear from the structure of the waterproof sheet described above, it is possible to exhibit sufficient anticorrosion effect, and
It is possible to prevent deterioration of the tarpaulin 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 "parts" or "%" are expressed as "parts by weight" or "% by weight." Example 1 An epoxy resin adhesive was applied on one side of a 1 mm 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 that, the thickness
A waterproof sheet was obtained by laminating a 50 μm copper foil. 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 waterside blasting. At that time, sufficient pressure was applied by hand to eliminate air bubbles and seawater between the substrate and the adhesive. This was left as it was, and tests and observations were conducted 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 above, a magnetic sheet with a thickness of 100 μm was applied.
Laminated with m copper alloy (copper-nickel) foil,
Got a tarpaulin. Construction was then carried out in the same manner as in Example 1, and tests and observations were conducted 12 months later. The results are shown in Table 1. Example 3 A waterproof sheet was prepared and installed in the same manner as in Example 1, except that a 200 μm thick copper foil was used as the metal foil laminate material, and tests and observations were conducted 12 months later. The results are shown in Table 1. Comparative example: Non-magnetic general rubber sheet (thickness 0.6mm)
The work was carried out in the same manner as in Example 1, 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.

【table】

[Table] * Measured using an Elcometer adhesion tester.
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 (1)

[Claims] 1. Apply an 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 to the underwater steel structure. The waterproof sheet is brought into contact with the surface of an object or the wet surface of a steel structure above the water surface, the waterproof sheet is spread over the surface of the steel structure, and the sheet is heated by a permanent magnet provided inside or outside of the sheet. A method for protecting steel structures, characterized by adhering them to their surfaces. 2. The method for protecting a steel structure according to claim 1, wherein the waterproof sheet contains magnetic particles.