JP2022019788A - Repair method of steel structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a repair method of a steel structure which makes weather resistance proper and which maintains high anticorrosion even after a lapse of long term after construction.

SOLUTION: A repair method of a steel structure repairs a surface of a metal material 20 which constitutes a part of a steel structure and contains at least one selected from a group consisting of iron and an alloy containing iron. The method comprises: a step of bonding a repairing adhesive tape 10 comprising a top coat substrate 12 and an adhesive layer 11 that is provided on one face of the top coat substrate 12 and contains a metal less noble in potential than iron, with the adhesive layer 11 as a bonding face, to a face 20A to be repaired of the metal material 20; and a step of forming a coating material film 30 by coating a top coat paint on the top coat substrate 12.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a repair method for repairing a steel structure composed of a steel material or the like.

Conventionally, zinc rich coating containing a large amount of zinc has been widely used in order to prevent corrosion of steel structures such as bridges, steel towers, viaducts, tanks, plants, and piers. Zinc is a metal having a lower potential than iron and is known to have a high anticorrosion property because it has a sacrificial anticorrosion effect. In order to protect the base material iron and steel from rust, it is necessary to apply undercoat, intermediate coat, and topcoat in addition to zinc-containing zinc rich coat. Since the previous process is completed for each coating and the next process is performed after the coating film has dried, it takes multiple days to complete the entire coating process, and partial repair has the same anticorrosion performance as the general part. It was difficult to grant.

In particular, when repainting a steel structure, a catch clamp is used to construct the scaffold, but since the part where the catch clamp is installed cannot be repainted, it is necessary to repair that part after dismantling the scaffold. Since the repair requires a substrate adjustment and a drying process, it takes several more days after the repainting is completed, and since it involves work at a high place, it is troublesome and dangerous. Therefore, there is a demand for a method for repairing a steel structure that can be easily repaired in a short time and has high corrosion resistance equivalent to that of a general painted portion.

Patent Document 1 is an invention relating to an inorganic zinc rich paint that can be used for heavy-duty anticorrosion coating of steel structures and can form a coating film capable of suppressing the generation of bubbles without performing a mist coating step. The invention of Patent Document 1 eliminates the need for a mist coat process, but it requires an undercoating step, an intermediate coating step, and a topcoating step on the zinc rich paint, and is not a process-saving repair method.

Patent Document 2 further improves sacrificial anticorrosion and the like by containing oxide particles containing at least one element selected from the group consisting of Si, Al and Mg and at least three types of zinc powder having different shapes. Although it is an invention relating to a food-preventing material containing zinc powder, it also does not provide a process-saving repair method.

Patent Document 3 has a layer structure composed of (a) a pressure-sensitive adhesive layer containing zinc powder and capable of imparting conductivity when pressed, (b) a zinc plate, (c) a resin film, and (d) a stainless steel plate. The present invention relates to an anticorrosion method in a pedestal portion of a pipe in which the anticorrosion member is brought into close contact with the adhesive layer so as to be in contact with the pedestal portion and the pipe is placed on the pedestal portion. The invention of Patent Document 3 is an invention aimed at providing an anticorrosion method capable of effectively delaying the progress of local corrosion in a pedestal portion of a pipe and extending the life of the entire pipe with simple construction. .. Although the present invention has made it possible to improve the corrosion resistance of the tubular object to be coated, it is not suitable for repairing steel structures including complicated shapes because it contains a stainless steel plate.

In Patent Document 4, a primer solution containing zinc powder and a partial hydrolyzate of an alkyl silicate is applied to the outer surface of the structure and dried to form a primer layer, and then the primer layer is formed on a support and the support. The present invention relates to an anticorrosion coating method, which comprises attaching and laminating an anticorrosion tape or a sheet composed of an provided adhesive layer. The invention of Patent Document 4 provides a metal pipe and a structure anticorrosion coating method capable of exhibiting an excellent anticorrosion effect even at high temperatures. Zinc powder is contained in a primer solution, and the anticorrosion is provided. There was room for improvement in performance.

Japanese Unexamined Patent Publication No. 2002-194284 Japanese Unexamined Patent Publication No. 2006-282856 Japanese Unexamined Patent Publication No. 60-204311 Japanese Unexamined Patent Publication No. 9-242982

The subject of the present invention has been made in view of the above-mentioned conventional problems, and is a steel that has good weather resistance and maintains high corrosion resistance even after a long period of time after construction, while saving a process. It is to provide a structure repair method.

As a result of diligent studies, the present inventors have made a pressure-sensitive adhesive that is provided on one surface of a topcoat base material and the topcoat base material on the surface to be repaired of a steel structure and contains a metal having a lower potential than iron. We have found that the above problems can be solved by affixing a repair adhesive tape provided with a layer and applying a predetermined topcoat paint on the adhesive tape to form a paint coating film, and have completed the following invention. In the present invention, even when the topcoat paint or the topcoat base material is cracked due to aged deterioration after painting, the pressure-sensitive adhesive is added to the sacrificial corrosion protection by the metal whose potential is lower than that of iron contained in the pressure-sensitive adhesive layer. Due to the self-healing performance of the layer, oxygen and water, which are corrosion factors, can be re-blocked, and the surface of the steel structure can be highly protected from corrosion.

That is, the present invention provides the following [1] to [10].
[1] A method for repairing the surface of a metal material that constitutes a part of a steel structure and contains at least one selected from the group consisting of iron and an alloy containing iron.
A repair adhesive tape provided with a topcoat base material and a pressure-sensitive adhesive layer provided on one surface of the topcoat base material and containing a metal having a lower potential than iron is provided on the surface to be repaired of the metal material. , The process of bonding with the adhesive layer as the bonding surface,
A method for repairing a steel structure, comprising a step of applying a topcoat paint on the topcoat base material to form a paint film.
[2] The method for repairing a steel structure according to the above [1], wherein the metal having a lower potential than iron is zinc.
[3] The method for repairing a steel structure according to the above [1] or [2], wherein the zinc content in the pressure-sensitive adhesive layer is 0.5 to 50% by mass.
[4] The steel structure according to any one of [1] to [3] above, wherein the pressure-sensitive adhesive layer contains a conductive material other than the metal and has a resistance value of ¹⁰⁸ Ω or less. Repair method.
[5] The item according to any one of [1] to [4] above, wherein the thickness of the pressure-sensitive adhesive layer is in the range of 20 μm to 1000 μm, and the thickness of the topcoat substrate is in the range of 10 μm to 120 μm. Steel structure repair method.
[6] The method for repairing a steel structure according to any one of [1] to [5] above, wherein the average surface roughness (Rzjis) of the surface to be repaired is within the range of 80 μm or less.
[7] The method for repairing a steel structure according to any one of the above [1] to [6], wherein the surface on which the topcoat paint of the topcoat base material is coated has a plurality of recesses having a depth of 1 to 50 μm.
[8] The topcoat paint contains at least one resin selected from acrylic resin, urethane resin, butadiene resin, silicone resin, fluorine resin, vinyl ester resin, and epoxy resin, or is an inorganic paint. The method for repairing a steel structure according to any one of [1] to [7].
[9] The top coat has a viscosity of 0.1 to 10,000 (Pa · s, 23 ° C.) at a shear rate of 0.1 s ^-1 and a viscosity of 0.05 to 10 (Pa · s, 23 ° C.) at a shear rate of 1000 s ^-1 . The method for repairing a steel structure according to any one of the above [1] to [8], which is Pa · s, 23 ° C.).
[10] The method for repairing a steel structure according to any one of [1] to [9] above, wherein the PVC (pigment volume concentration) of the topcoat paint is in the range of 10 to 40.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for repairing a steel structure, which has good weather resistance and maintains high corrosion resistance even after long-term use, while saving a process.

It is a schematic sectional drawing which shows the steel structure repair method which concerns on one Embodiment of this invention.

Hereinafter, the present invention will be described with reference to the embodiments.
The method for repairing a steel structure of the present invention is a method for repairing the surface of a metal material that constitutes a part of a steel structure, and as shown in FIG. 1, the repair target surface 20A of the metal material 20 is used. A step (A1) of adhering the repair adhesive tape 10 and a step (A2) of applying a top coat paint on the repair adhesive tape 10 to form a paint coating film 30 are provided.

Hereinafter, the method for repairing a steel structure of the present invention will be described in detail.
<Process (A1)>
The repair adhesive tape 10 includes a topcoat base material 12 and an adhesive layer 11 provided on one surface of the topcoat base material 12. In the step (A1), the repair adhesive tape 10 is attached to the repair target surface 20A of the metal material 20 with the adhesive layer 11 as the bonding surface.

[Metallic material]
The metal material 20 to be the surface to be repaired 20A is a metal material containing at least one selected from the group consisting of iron and an alloy containing iron. Specific examples of the alloy containing iron include alloy steels such as nickel chrome steel, nickel chrome molybdenum steel, chrome steel, chrome molybdenum steel and manganese steel, and various steel materials such as carbon steel. Since a steel material is generally used in a steel structure, a steel material is preferable as the metal material 20.
In general, a steel structure is coated with a rust-preventive paint, an anti-corrosion paint, etc. on a metal material such as a steel material at the time of completion in order to impart rust-preventive and anti-corrosion properties. It is formed. Such a coating film 25 is partially peeled off or damaged due to deterioration over time, construction work or repair performed on a steel structure, or the like. In the present invention, it is advisable to attach the repair adhesive tape 10 to the portion where the pre-repair coating film 25 is damaged.
The steel structure is not particularly limited, and examples thereof include bridges, steel towers, viaducts, tanks, plants, and piers.

Further, before the step (A1), the base material adjustment such as polishing treatment may be performed on the metal material 20 of the steel structure which is the surface to be repaired 20A. By adjusting the substrate, the pre-repair coating 25 that has conventionally existed on the surface to be repaired 20A can be removed, and the repair adhesive tape can be directly attached to the surface of the steel material. Generally, in the substrate adjustment when painting a paint, it is preferable to increase the surface roughness to some extent from the viewpoint of increasing the adhesive force of the paint, but in the present invention, the surface to be repaired 20A is smoothed. Therefore, the adhesiveness of the pressure-sensitive adhesive layer 11 to the metal material 20 can be improved.
The average surface roughness (Rzjis) of the surface to be repaired 20A is preferably 80 μm or less, more preferably 40 μm or less, from the viewpoint of enhancing the smoothness of the surface. The average surface roughness (Rzjis) is a ten-point average roughness measured according to JIS B 0601: 2001.

[Adhesive tape for repair]
The pressure-sensitive adhesive layer 11 used for the repair pressure-sensitive adhesive tape contains a metal having a lower potential than iron. The pressure-sensitive adhesive layer 11 has a sacrificial anticorrosion property by containing a metal having a lower potential than iron (hereinafter, also referred to as "sacrificial anticorrosion metal"), and is a metal material to which the repair adhesive tape 10 is attached. 20 anticorrosion properties are ensured. Further, the adhesive layer 11 containing the sacrificial anticorrosion metal has good adhesiveness to the metal material 20 without significantly impairing the flexibility of the repair adhesive tape 10, and even after a long period of time has passed since the repair. It becomes easier to secure anticorrosion.

Further, the pressure-sensitive adhesive layer 11 may further contain a conductive material other than the sacrificial anticorrosion metal. The pressure-sensitive adhesive layer 11 contains a conductive material to increase the conductivity. Specifically, the resistance value of the pressure-sensitive adhesive layer 11 is preferably ¹⁰⁸ Ω or less. Therefore, it becomes possible to sufficiently transfer the electrons emitted when the sacrificial anticorrosion metal is ionized to the metal material 20, and it is good without increasing the content of the sacrificial anticorrosion metal in the pressure-sensitive adhesive layer 11. Sacrificial anticorrosion is guaranteed.

(Metal with lower potential than iron)
Examples of the metal having a lower potential than iron (metal for sacrificial anticorrosion) include cadmium, chromium, zinc, manganese, aluminum and the like, and among these, zinc and aluminum are preferable, and zinc is particularly preferable. By using zinc, sacrificial anticorrosion is excellent.
The sacrificial anticorrosion metal may be dispersed in the pressure-sensitive adhesive layer 11 as a filler in any form such as a particle shape, a scale shape, a spindle shape, etc., but preferably contains a particle shape. By forming the sacrificial anticorrosion metal into a particle shape, the adhesive layer 11 can be easily dispersed in the adhesive layer 11 without reducing the adhesiveness of the adhesive layer 11.
In the present specification, the particle shape means that the ratio (aspect ratio) of the length in the major axis direction to the length in the minor axis direction is small, and for example, the aspect ratio is 3 or less, preferably 2 or less. The particle shape is not particularly limited, but may be spherical or irregular such as powder. The particle size of the metal has a particle size of, for example, 1 to 500 μm, preferably 1 to 200 μm. In the present specification, the particle size means the average particle size measured by the laser diffraction method.
The content of the sacrificial anticorrosion metal is, for example, 0.5 to 50% by mass, preferably 1 to 40% by mass, based on the total amount of the pressure-sensitive adhesive layer 11.

(Conductive material)
Examples of the conductive material include one or more selected from carbon-based materials, metal-based materials, metal oxide-based materials, ionic polymers, and conductive polymers.
Examples of carbon-based materials include carbon black, graphite, graphene, carbon nanotubes, and acetylene black. Examples of the metal-based material include metals having a higher potential than iron, such as gold, silver, copper, nickel, or alloys containing these, or iron. Examples of the metal oxide material include indium tin oxide (ITO), antimony trioxide (ATO), fluorine-doped tin oxide (FTO), zinc oxide and the like. Examples of the conductive polymer include polyacetylene, polypyrrole, PEDOT (polyethylenedioxythiophene), PEDOT / PSS (complex of polyethylenedioxythiophene and polystyrene sulfonic acid), polythiophene, polyaniline, poly (p-phenylene), polyfluorene, and the like. Examples thereof include polycarbazole, polysilane, and derivatives thereof. Examples of the ionic polymer include sodium polyacrylate and potassium polyacrylate.
As the conductive material, one of these may be used alone, or two or more of them may be used in combination.

The conductive material is not particularly limited as long as it can be dispersed or compatible with the pressure-sensitive adhesive layer 11, but is preferably in the form of particles or is compatible with the pressure-sensitive adhesive described later. The particle-shaped conductive material has a particle size of, for example, 1 to 200 μm.
The content of the conductive material in the pressure-sensitive adhesive layer 11 is, for example, 1 to 50 parts by mass, preferably 2 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive, from the viewpoint of excellent adhesiveness to the metal material and sacrificial corrosion resistance. ~ 30 parts by mass.
The thickness of the pressure-sensitive adhesive layer 11 is not particularly limited, but is, for example, 20 μm to 1 cm, preferably 20 μm to 900 μm, and more preferably 50 to 700 μm.

(Adhesive)
The pressure-sensitive adhesive layer 11 is formed by blending a sacrificial anticorrosion metal, a sacrificial anticorrosion metal, and a conductive material with the pressure-sensitive adhesive. Examples of the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 11 include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a silicone-based pressure-sensitive adhesive. These may be used alone or in combination. Among these, it is preferable to use an acrylic pressure-sensitive adhesive. When an acrylic pressure-sensitive adhesive is used, it becomes easy to adjust the adhesive strength to a desired range, and it becomes easy to improve the adhesiveness to a metal material.

[Topcoat base material]
Examples of the topcoat base material 12 include acrylic resins, vinyl chloride resins, ABS resins (acrylonitrile-butadiene-styrene copolymer), styrene resins, polycarbonate resins, polyethylene terephthalates, and ester resins such as polyethylene naphthalate. Examples thereof include polyolefin resins such as polyethylene, polypropylene and ethylene-propylene copolymers, amide resins and polyurethane resins, and among these, acrylic resins are preferable. By using an acrylic resin or the like, the solvent of the topcoat paint is prevented from seeping into the topcoat base material, and the adhesiveness of the pressure-sensitive adhesive layer 11 to the surface to be repaired 20A is prevented from being lowered. The base material may be a single-layer resin film made of the resin, or may be a resin film having a multi-layer structure.

Examples of the acrylic resin include acrylic resins such as polymethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-butyl (meth) acrylate copolymer, and methyl (meth) acrylate-styrene copolymer. Can be mentioned. These acrylic resins may be used alone or in combination of two or more.
In the present invention, "(meth) acrylate" means "acrylate" or "methacrylate".

The thickness of the topcoat base material 12 is preferably 10 to 120 μm, more preferably 20 to 100 μm, and even more preferably 30 to 80 μm. When the thickness of the topcoat base material 12 is at least the above lower limit value, the strength of the topcoat base material 12 is ensured, and the weather resistance and the like are likely to be good. Further, it is possible to prevent the solvent contained in the top coat paint from seeping into the repair adhesive tape 10.
On the other hand, when the thickness of the topcoat base material 12 is not more than the upper limit, the followability of the surface to be repaired 20A to the step is improved, the adhesiveness of the pressure-sensitive adhesive layer 11 to the surface to be repaired 20A, and the paint coating on the topcoat base material 12. The adhesiveness of the film 30 is likely to be improved, and the anticorrosion property is easily ensured even after a long period of time has passed since the repair.

It is preferable that the topcoat base material 12 has a plurality of recesses formed by embossing or the like. The recesses may be formed at least on the surface to which the topcoat paint of the topcoat base material 12 is applied. When the recess is formed in the topcoat base material 12, the adhesion to the paint coating film 30 is improved, the workability at the time of construction is improved, and the paint coating film 30 is less likely to be peeled off for a long period after the construction.
As a method of embossing the topcoat base material 12, an embossing method by heating and pressurizing is usually used. The embossing method by heating and pressurizing is a method in which the surface of the various resin films described above is heated and softened, pressed by an embossed plate to form an uneven pattern on the embossed plate, cooled, and fixed. A single-wafer type or rotary type embossing machine can be used.

The depth of the recess formed by embossing or the like is preferably 1 to 50 μm, more preferably 2 to 30 μm, still more preferably 5 to 20 μm. When the depth of the recess is not less than the lower limit, the adhesion to the paint film 30 is improved. On the other hand, when the depth of the recess is not more than the upper limit value, the topcoat base material 12 is less likely to be torn, which is preferable. The depth of the recess means the average value of the depths from the flat surface of the surface of the topcoat base material 12 to the bottom of the recesses, and it is preferable to calculate the average value of the depths of 20 arbitrarily selected recesses. ..

The front surface, back surface, or both sides of the top coat base material 12 are subjected to treatments such as corona discharge treatment, plasma treatment, and primer layer formation in order to improve the adhesion of the pressure-sensitive adhesive layer 11 and the paint film coating film 30 to the top coat base material 12. You may.
The topcoat base material 12 may contain various additives such as stabilizers, plasticizers, colorants, ultraviolet absorbers, hindered amine-based light stabilizers, and extender pigments, if necessary. The topcoat base material 12 may be colored, in which case a known colorant can be used.

Further, the bonded surface of the repair adhesive tape 10 may be protected by a release sheet attached before being bonded to the repair target surface 20A. As the release sheet, a sheet in which at least one surface of a base material such as a resin film is peeled off with a silicone-based release agent or the like is used.

<Process (A2)>
In the step (A2), a topcoat paint (paint composition) is applied onto the topcoat base material 12 to form a paint film 30. In the present invention, by forming the paint coating film 30 with the topcoat paint, the weather resistance is improved, and the anticorrosion property is ensured even after a long period of time has passed since the construction. Further, when the top coat paint contains a pigment described later, it is possible to perform color matching with the pre-repair coating film 25 around the repair target surface 20A that has already been painted.

(Topcoat paint)
The topcoat paint to be coated on the topcoat base material 12 is a resin paint containing at least one resin selected from urethane resin, acrylic resin, butadiene resin, silicone resin, fluorine resin, vinyl ester resin, epoxy resin and the like, or a resin paint containing at least one resin. Examples include inorganic paints. Each resin paint may be either a one-component type or a two-component type.

Further, the paint preferably contains a pigment. As the pigment, various pigments such as coloring pigments and extender pigments can be used, and it is preferable to use both of them. Preferable examples of the coloring pigment include inorganic pigments such as titanium oxide, carbon black, black iron oxide, red iron oxide, yellow iron oxide and cobalt blue, and organic pigments such as phthalocyanine pigments and azo pigments. The coloring pigment may be appropriately selected according to the color of the pre-repair coating film 25 around the repair target surface 20A of the steel structure.
Examples of the extender pigment include calcium carbonate, silica, alumina, hydrated alumina, magnesia, talc, clay, barium sulfate, barium carbonate, wollastonite, ceramic powder, glass fiber powder, white carbon, magnesium silicate and the like. Can be mentioned.
These pigments may be used alone or in combination of two or more.
In the present invention, the PVC (pigment volume concentration) of the top coat is preferably in the range of 10 to 40.

The topcoat paint (paint composition) may contain an organic solvent or water for the purpose of adjusting the viscosity or the like. Examples of the organic solvent include aromatic hydrocarbons, aliphatic hydrocarbons, ketones, acetates, ethers, alcohol solvents, mineral spirits and the like.

In the present invention, the topcoat paint includes a dispersant, an antifoaming agent, a thickener, a leveling agent, an anti-settling agent, an anti-sagging agent, an algae-proofing agent, an antifungal agent, a preservative, an ultraviolet absorber, and a light stabilizer. Additives such as and the like may be appropriately blended as needed.

The viscosity of the top coat is preferably 0.1 to 10,000 Pa · s at a shear rate of 0.1 s ^-1 and 0.05 to 10 Pa · s at a shear rate of 1,000 s ^-1 . When the viscosity at each shear rate is within the above range, the coating workability and sagging property are excellent, so that it is possible to easily form a coating film having a required film thickness in one coating. From these viewpoints, the viscosity at a shear rate of 0.1 s ^-1 is more preferably 0.2 to 7,000 Pa · s, and even more preferably 0.5 to 5,000 Pa · s. The viscosity at a shear rate of 1,000 s ^-1 is more preferably 0.08 to 8 Pa · s, and even more preferably 0.1 to 6 Pa · s.
In the present invention, the viscosity of the top coat is measured after adjusting the liquid temperature to 23 ° C. using a leometer ARES manufactured by TA Instruments. In the two-component curing type, the viscosity is immediately after the two components (main agent and curing agent) are mixed.
The thickness of the paint film 30 formed by the top coat is preferably 15 μm or more.

[How to apply topcoat paint]
The method of applying the topcoat paint is not particularly limited, but the topcoat paint is applied onto the topcoat base material 12 by ordinary coating means such as spray coating, roller coating, and brush coating, and the paint is naturally dried or forcibly dried. The coating film 30 may be formed. Further, the topcoat paint may be applied so as to form a paint film 30 on the surface of the topcoat base material 12, but as shown in FIG. 1, the metal material 20 of the steel structure and the paint film 25 before repair may be used. It may be painted according to the surface.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
[Making adhesive tape for repair]
A 600 μm-thick pressure-sensitive adhesive layer composed of a pressure-sensitive adhesive composition in which 15 parts by mass of zinc particles (13% by mass based on the total amount of the pressure-sensitive adhesive layer) is mixed with 100 parts by mass of the pressure-sensitive adhesive having the formulations shown in Table 1 is overcoated. It was formed on one surface of the substrate. The topcoat base material was made of an acrylic resin film having a thickness of 50 μm, and the other surface of the topcoat base material was embossed, and the depth of the recess was 5 μm.

* Each component in Table 1 is as follows.
Olefin polymer: Trade name "L-1253", manufactured by Kuraray Co., Ltd., hydrogenated polybutadiene adhesive-imparting resin having a (meth) acryloyl group at one end 1: Trade name "Arcon P140", manufactured by Arakawa Chemical Industry Co., Ltd., water Hydrogenated petroleum resin, softening point 140 ° C
Adhesive-imparting resin 2: Product name "Arcon P100", manufactured by Arakawa Chemical Industry Co., Ltd., hydrogenated petroleum resin, softening point 100 ° C.
Fine particles: Product name "Cellstar Z-27", manufactured by Tokai Kogyo Co., Ltd., glass balloon cross-linking agent: product name "TEAI-1000", manufactured by Nippon Soda Co., Ltd. Polymerization initiator: 2,2-dimethoxy-2-phenylacetophenone

[Preparation of test sample]
As a test plate, a repair adhesive tape is attached to a grit blasted steel plate (150 x 70 x 3.2 mm) with an ISO 8501-1 Sa2.5 substrate adjustment so that the adhesive layer serves as the bonding surface. rice field. Then, a paint obtained by mixing the main agent and the curing agent shown in Tables 2 to 4 as a topcoat paint on the topcoat base material of the adhesive tape for repair is dried using a brush to have a thickness of 25 to 25. The coating was applied to a temperature of 35 μm and dried in a constant temperature room maintained at a temperature of 23 ° C. and a relative humidity of 50% for 7 days to form a paint coating film, and a test sample was obtained.

(Examples 2 to 6)
The same procedure as in Example 1 was carried out except that the content of zinc blended in the pressure-sensitive adhesive layer was changed as shown in Table 2.

(Example 7)
The same procedure as in Example 1 was carried out except that the metal having a lower potential than that of iron blended in the pressure-sensitive adhesive layer was changed to aluminum particles.

(Examples 8 and 9)
The procedure was carried out in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was changed as shown in Table 3.

(Examples 10 to 13)
The procedure was carried out in the same manner as in Example 1 except that the thickness of the topcoat base material and the depth of the recess formed by the embossing were changed as shown in Table 3.

(Examples 14 to 17)
The procedure was carried out in the same manner as in Example 1 except that the composition of the main agent and the curing agent of the topcoat paint was changed as shown in Table 4.

(Example 18)
The same procedure as in Example 1 was carried out except that a test plate having an average surface roughness of 75 μm was used.

(Comparative Example 1)
The procedure was carried out in the same manner as in Example 1 except that zinc was not added to the pressure-sensitive adhesive layer.

(Comparative Example 2)
The procedure was carried out in the same manner as in Example 1 except that the paint was not applied.

[Adhesion test]
In the test samples obtained in the above Examples and Comparative Examples, the adhesiveness of the pressure-sensitive adhesive layer to the steel sheet was evaluated according to the following evaluation criteria.
A: The adhesiveness of the pressure-sensitive adhesive layer to the steel sheet was good.
B: The adhesiveness of the pressure-sensitive adhesive layer to the steel sheet was at a practically usable level.
C: The adhesiveness of the pressure-sensitive adhesive layer to the steel sheet was low.

[Adhesion test]
In the test samples obtained in the above Examples and Comparative Examples, the adhesion of the paint film to the topcoat substrate was evaluated by JIS K5600-5.6: 1999 (2 mm interval 25 squares), and according to the following evaluation criteria. evaluated.
A: No peeling was observed on any of the grids.
B: There was peeling within 15% of the entire lattice.
C: There was more than 15% peeling on the entire grid.

[Anti-corrosion test]
In the test samples obtained in the above Examples and Comparative Examples, the corrosion resistance to the steel sheet was evaluated by the JIS K5600-7-1: 1999 salt spray test and evaluated according to the following evaluation criteria.
A: There was no abnormality around the cross-cut portion, and the corrosion resistance was good.
B: Although red rust and blisters with a diameter of less than 2 mm were generated around the cross-cut portion, the anticorrosion property was at a practically usable level.
C: Red rust and blisters with a diameter of 2 mm or more were generated around the cross-cut portion, and the corrosion resistance was low.

[Weather resistance test]
The weather resistance of the test samples obtained in the above Examples and Comparative Examples was evaluated by the accelerated weather resistance test (1000 hours) described in JIS K5600-7-7 and evaluated according to the following evaluation criteria.
A: The gloss retention rate after 1000 hours was 70% or more.
B: The gloss retention rate after 1000 hours was 50% or more and less than 70%.
C: The gloss retention rate after 1000 hours was less than 50%.

The resins 1 to 3 and the curing agents 1 to 3 in Tables 2 to 4 are as follows.
Resin 1: Acridic A-829, NV = 60% by mass (DIC Corporation)
Resin 2: Acridic A-837, NV = 50% by mass (DIC Corporation)
Resin 3: Barnock WE-301, NV = 45% by mass (DIC Corporation)
Hardener 1: Duranate TPA-100, NV = 100% by mass (Asahi Kasei Chemicals)
Hardener 2: Duranate TSA-100, NV = 100% by mass (Asahi Kasei Chemicals)
Hardener 3: Burnock DNW-6000, NV = 100% by mass (DIC Corporation)

As is clear from the above examples, according to the steel structure repair method of the present invention, the weather resistance and corrosion resistance are good, the adhesion to the top coat base material of the paint film, and the steel plate of the pressure-sensitive adhesive layer. Where the adhesiveness is good, high anticorrosion properties are maintained even after a long period of time after repair.

10 Adhesive tape for repair 11 Adhesive layer 12 Topcoat base material 20 Metal material 20A Repair target surface 25 Pre-repair coating film 30 Paint coating film

Claims (10)

A method of repairing the surface of a metal material that constitutes a part of a steel structure and contains at least one selected from the group consisting of iron and an alloy containing iron.
A repair adhesive tape provided with a topcoat base material and a pressure-sensitive adhesive layer provided on one surface of the topcoat base material and containing a metal having a lower potential than iron is provided on the surface to be repaired of the metal material. , The process of bonding with the adhesive layer as the bonding surface,
A method for repairing a steel structure, comprising a step of applying a topcoat paint on the topcoat base material to form a paint film. The method for repairing a steel structure according to claim 1, wherein the metal having a lower potential than iron is zinc. The method for repairing a steel structure according to claim 2, wherein the zinc content in the pressure-sensitive adhesive layer is 0.5 to 50% by mass. The method for repairing a steel structure according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer contains a conductive material other than the metal and has a resistance value of ¹⁰⁸ Ω or less. The method for repairing a steel structure according to any one of claims 1 to 4, wherein the thickness of the pressure-sensitive adhesive layer is in the range of 20 μm to 1000 μm, and the thickness of the topcoat base material is in the range of 10 μm to 120 μm. The method for repairing a steel structure according to any one of claims 1 to 5, wherein the average surface roughness (Rzjis) of the surface to be repaired is within the range of 80 μm or less. The method for repairing a steel structure according to any one of claims 1 to 6, wherein the surface on which the topcoat paint of the topcoat base material is coated has a plurality of recesses having a depth of 1 to 50 μm. Claim 1 to claim 1, wherein the topcoat paint contains at least one resin selected from an acrylic resin, a urethane resin, a butadiene resin, a silicone resin, a fluorine resin, a vinyl ester resin, and an epoxy resin, or is an inorganic paint. 7. The method for repairing a steel structure according to any one of 7. The topcoat paint has a viscosity of 0.1 to 10,000 (Pa · s, 23 ° C.) at a shear rate of 0.1 s ^-1 and a viscosity of 0.05 to 10 (Pa · s) at a shear rate of 1000 s ^-1 . , 23 ° C.), the method for repairing a steel structure according to any one of claims 1 to 8. The method for repairing a steel structure according to any one of claims 1 to 9, wherein the PVC (pigment volume concentration) of the topcoat paint is in the range of 10 to 40.

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