JPS609868B2 - Corrosion-proof turning method for steel structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for applying corrosion protection to steel structures, particularly marine and river steel structures where corrosive environments are severe, from splashed parts to submerged parts.

In recent years, various steel horizontal structures (for example, the largest bridges, pipelines, submarine bases, oil field drilling equipment, port facilities, etc.) have been constructed or are about to be constructed due to the offshore development boom.

Such steel structures have submerged parts that are constantly submerged in water,
It can be roughly divided into the tidal area, which may or may not be submerged in water depending on the ebb and flow of the tide, the splash area, which is sprayed by water waves, and the upper part exposed to the atmosphere, and the corrosive environment in each area. Since these are not the same, it becomes an important issue how to apply excellent anti-corrosion treatment to these. The present invention relates to a corrosion-proofing construction method for such a steel horizontal structure, particularly in the area from the submerged part to the splashed part (referred to as the underwater part). Conventionally, the corrosion protection method for underwater parts of new and existing steel structures has mainly been carried out by painting with underwater curing paints.

However, the underwater area has poor footing conditions, making it extremely difficult to work with the coating.Furthermore, it is directly affected by the waves, making it difficult to work by hand. Due to the effects of this, it is difficult to peel off. Furthermore, ``Painting is done by hand, which is inefficient, and the film thickness is uneven, resulting in problems with anticorrosive effects.''On the other hand, instead of painting with underwater curing paint, Anti-corrosion has also been carried out by wrapping anti-corrosion tape while wrapping, but considering the scaffolding conditions, the workability is worse than applying the above-mentioned paint.
Moreover, it is extremely difficult to wrap the steel structure tightly and uniformly around parts where the shape of the steel structure is complex or to the joints. Furthermore, this fact is not limited to marine structures;
Even floating steel structures constructed on rivers, lakes, etc. have the same problems as described above, although there are differences in degree. Therefore, there is a strong demand for an efficient corrosion protection construction method for the underwater parts of these steel structures. Therefore, the present inventors investigated a method of applying anti-corrosion treatment to the underwater part during on-site construction, and found that an uncured forming plate made of an underwater curing paint with a mesh sheet embedded therein could be used for anti-corrosion treatment. They found that it has appropriate flexibility and can be easily applied to any shape of underwater part of a steel structure to achieve anti-corrosion construction, and thus completed the present invention.

That is, the present invention relates to a method of applying anti-corrosion to a steel structure, which comprises adhering to the steel structure an uncured forming plate made of an underwater curable paint containing a mesh sheet.

The parts of a steel structure to which the anticorrosion treatment of the present invention is applied are mainly underwater parts (parts ranging from submerged parts to splashed parts) where there is a possibility of being affected by water (including seawater).

Whether it is repairing an existing steel structure or constructing a new one, pre-treatment of the anti-corrosion area is necessary to remove insects, shellfish, etc.
It is particularly preferable to remove impurities such as algae, or if rust is observed, to smooth the area so as not to interfere with the adhesion of the uncured forming plate. After performing such pretreatment, an uncured forming plate, which is a feature of the present invention, is attached.

This forming plate is required to be easily prepared in the field. This is because the environment at the work site is poor and water-curing paints have a limited potlife, so they must be used immediately after preparation. This forming plate is an uncured plate made of underwater curing paint with a mesh sheet inside, and its preparation method involves, for example, pasting it onto a smooth plate provided with a film thickness guide. A mesh sheet cut into a size that is passed through is placed, and an underwater curable paint is spread on the sheet to a constant film thickness.

For example, when the paint is rolled out smoothly by hand or with a roller (such as a commercially available Knapp roller or plastic roller), it becomes like a mesh sheet inserted into the underwater curable paint layer, and one end of the sheet By peeling it off, the formed plate that is the object of the present invention can be easily obtained.Another preparation method is to spread an underwater curable paint, spread a mesh sheet, and then apply the paint on top of it. Also, the method for preparing the forming plate used in the present invention is not limited to these methods in any way. An example is a type of solvent-free epoxy resin paint (curing agent component is polyad type).

This paint is a two-component type that uniformly mixes the resin component and the curing agent component when used, and because it has a limited shelf life (approximately 2 hours for 2000), it is used to coat the forming board. It is preferable to attach it to a copper structure immediately after preparation. The characteristics of this paint include, for example, the resin component is 2
0000 poise/250C or more, curing agent component is 1000
The temperature is over 25 degrees Celsius, and it is highly viscous and putty-like. Therefore, the film thickness of the forming plate used in the present invention can be adjusted arbitrarily, and from the viewpoint of adhesion to steel structures, anti-corrosion effect, etc., the thickness of 2 to IQ ribs is particularly appropriate. The forming plate has good adhesion to steel surface materials even on wet surfaces where moisture is present, and has excellent water resistance and flexibility. The mesh sheet provides flexibility during the process of adhering the forming plate to the steel structure, and also serves as the core of the forming plate, making it suitable for underwater curing paints. It must not peel off from the sheet.

Materials used for the mesh sheet include steel, stainless steel, metals such as true steel, synthetic fibers, natural fibers, etc.
Iron, polypropylene (Synthetic fibers such as nylon, polyethylene, and vinylon are preferable because they have appropriate flexibility.When using a mesh sheet of iron, be sure to fully coat the underwater curable paint layer to prevent the iron from being cast. In addition, the shape of the mesh of the mesh sheet is not particularly limited, such as triangular, square, hexagonal, diamond, etc., and the weaving method of the mesh is also arbitrary.The size of the mesh is It is preferable to use fine mesh to prevent the hardening paint from peeling or falling off during the application process, such as those with fine meshes such as commercially available insect nets, window nets, and fish nets.
In addition, when using an iron mesh, it is desirable to use a wire mesh of 0.1 to 0.5 skin in terms of flexibility and thickness, and as the wire diameter becomes larger, it will not have flexibility and will also become thicker. There is a risk that the core will not work and workability will decrease. Also, synthetic fibers and the like can be used, the wire diameter of which is approximately the same as that of iron. In addition, these mesh sheets can be easily cut with scissors, cutters, etc. without the need for a special cutting machine, so it is possible to prepare the forming plate to a size or shape suitable for the corrosion protection area. The method of applying the formed plate prepared in this way to the corrosion-protected part of a steel structure, particularly in the underwater part, is carried out by attaching the forming plate prepared to a predetermined size to the part to be constructed while pressing it.

When pasting multiple sheets, the forming plates can be stacked together by overlapping the ends of each forming plate. Then, by pressing and sticking the folded part so that it is caught, a strongly bonded continuous film can be formed. Since the forming plate is in a hardened state, it is possible to easily make the mesh sheet continuous and adhere to the construction area even in water by simply holding it down by hand. In addition, even if the anti-corrosion construction part has a complicated shape, the size and shape of the L-forming plate can be adjusted arbitrarily, and it has excellent formability, so it can be used even in the shape of concave parts or partitions of L-shaped steel, H-shaped steel, etc. Construction is easy.The anticorrosion construction method of the present invention is mainly intended for application to parts of marine or river steel structures that are severely corrosive and difficult to work in, such as underwater parts. It is something.

First, the present invention is characterized in that on-site work can be carried out easily and with improved productivity compared to conventional methods. In addition, the resulting anticorrosion coating layer adheres uniformly, has a uniform thickness, and exhibits excellent anticorrosion effects. This allows the preparation of an uncured underwater curable paint-coated forming plate on-site, and the forming plate takes full advantage of the role of a mesh sheet rather than simply using an underwater curable paint. This is brought about by the fact that In particular, by using an uncured underwater curable paint coating plate, the work can be done easily and quickly without peeling or falling off the paint even under slightly adverse working conditions (such as strong waves). Since it can improve workability, it will greatly contribute to the corrosion prevention treatment of future repairs or new construction of marine structures. Note that it is of course possible to use other cathodic protection treatments together with this anticorrosion treatment. The present invention will be explained below with reference to Examples and Comparative Examples.

Example 3 Made of polypropylene (diameter 0.3 legs) on smooth plywood with a dry surface
Commercially available window silk sheet (20 mesh, vertical 15
Lay out a sheet (60 skin x width 60 skin) and place guides (3.5 thick willow, wooden) on each end of the sheet.

Next, two-component epoxy resin paint (resin component 350003
Poise/2500, polyamide 16000 Poiseno 25
00, manufactured by Kansai Paint Co., Ltd., product name equivalent to Napco Barrier-N) was uniformly mixed and dispersed using a screw pump, and then applied to the sheet using a spatula. The amount of paint used was approximately 5 [9]. Use a commercially available Knapp roller to evenly roll it out to the height of the guide. Then,
When the sheet was peeled off from the plywood, the desired uncured underwater curable paint-coated board was obtained. In this product, the sheet acts as a core and has flexibility, and the sheet is inserted into the coating layer and does not protrude when being carried.
The paint did not come off either. This thing, shellfish, insects,
It was applied to the flat part of the ebb and flow part of a marine steel structure and the groove part of the H-beam steel after removing any deposits such as debris. Just by pressing the forming plate by hand, it adhered tightly, and a firm film was formed after 2 hours without falling off due to the influence of waves. Comparative Example 1 A worker manually applied a prepared two-component epoxy resin paint to the flat part of the ebb and flow part of a marine steel structure and the groove part of the H-shaped steel, which had been cleaned of deposits such as shellfish, insects, and algae, as in Example 1. But I applied it.

In this case, the film thickness was not uniform and the paint often fell off due to the influence of waves, and the coating efficiency was extremely reduced and it took three times as long to coat the same area as in the example. (
If we calculate that the amount of work that can be done underwater per day is 5 hours, we were able to coat only the second area per day. ) Comparative Example 2 In the example, the mesh sheet used for the underwater curable paint coating forming board was a woven wire mesh with 1 cover and 5 meshes.

Claims (1)

[Claims] 1. A method for applying anti-corrosion to a steel structure, which comprises adhering to the steel structure an uncured forming plate made of an underwater curing paint containing a mesh sheet.