JPS6282022A - Corrosion prevention method for steel - Google Patents

Abstract

PURPOSE:To provide a corrosion prevention method which displays favorable corrosion prevention properties even to a high-temperature steel material and does not necessitate a special heating device at the time of execution of the method, by applying an undercoating agent containing a curing agent which can cure a thermosetting resin composite at the normal temperature to the surface of the steel, lap-winding an inner layer material corrosion prevention tape constituted by forming the thermosetting resin composite and lap-winding an outer layer material, further thereon. CONSTITUTION:An undercoating agent 2 constituted by containing a curing agent which is capable of curing a thermosetting resin composite at the normal temperature is applied to the surface of a steel material 1. Lap-winding of an inner layer material corrosion prevention tape 3 constituted by forming a thermosetting resin composite layer constituted by containing plastic fiber cloth in its interior is performed over a plastic film. The lap-winding of an outer layer material tape 4 which serves as an adhesive layer composed of an adhesive compound and base material composed of a plastic sheet or rubber sheet is performed further over the inner material corrosion prevention tape 3. The undercoating agent improves wetting and adhesive properties of the thermosetting resin composite layer constituting the inner layer material corrosion prevention tape to the surface of the steel material. The above thermosetting resin layer can be cured by a normal temperature curing agent in a short period of time at least in the vicinity of the steel material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for preventing corrosion of steel materials, and more particularly to a method of preventing corrosion of steel materials using an anticorrosion tape.

[Prior art]

2. Description of the Related Art One method of transporting fluids such as oil and gas is to construct pipelines using steel pipes.

One problem with such methods is that the steel pipes corrode.

Various methods have been used to prevent corrosion of steel pipes.

One method is to protect the surface of the steel pipe with bituminous material. However, this method has the problem that the bituminous material layer is easily damaged by external impacts.

In recent years, as a method to solve the problems of such methods, a method has been adopted in which the surface of the steel pipe is coated with plastics such as polyethylene and polyvinyl chloride.

The following three methods are generally known for coating the surface of steel pipes with plastics.

1) A method in which a steel pipe is heated, an undercoating composition is applied to the surface of the pipe, the surface is coated with molten plastic, and the pipe is cooled.

2) A method in which plastics are processed into a cylindrical heat-shrinkable pipe in advance, this is attached to a steel pipe coated with a surface undercoating composition, and the pipe is heated to shrink and coat the pipe.

3) Plastic is formed into a tape shape in advance, and an adhesive layer is formed on one surface of the tape, and this is wrapped spirally around the surface of a steel pipe on which an undercoat composition has been applied, overlapping a portion of the tape. The so-called anti-corrosion tape coating method.

In this way, coated steel pipes protected by plastics are
Compared to the steel pipes protected by bituminous materials, it has remarkable effects in terms of corrosion prevention effect and service life.

However, the undercoat or adhesive layer used in these methods is either a thermoplastic resin or a rubber-based material, and at high temperatures the layer to be subjected to ri gets softened and becomes vulnerable to physical impact, causing it to break. or may lose adhesion to metals and become irritable.
, defects such as M shifting or peeling occur. The problem is that water and oxygen enter through such defective parts, causing corrosion to occur and progress, that is, the corrosion resistance deteriorates.

Furthermore, in pipelines for transporting fluids such as petroleum and heavy oil, the fluid is usually pressurized and heated to reduce its viscosity and improve transport efficiency. When applying a plastic coating with inferior quality, there was also a problem that there was a limit to the usage limit. In order to solve these drawbacks of plastic coatings, various countermeasures have been considered in the past, and the following attempts have also been made in anticorrosion tape construction methods. For example, in the anticorrosion tape construction method, a plastic sheet with a higher softening point is used as the support for the anticorrosion tape used, and in some cases, attempts are being made to attach a heat-resistant release base material to the plastic sheet. is also being carried out. This attempt is excellent in improving the heat resistance of the support for anticorrosive tapes.

However, if the adhesive layer is made of rubber or thermoplastic resin that does not easily soften at high temperatures, it will not exhibit adhesive properties at room temperature, the temperature at which the tape is applied, and the steel pipe will be heated. Construction must be carried out at the same time. This greatly impairs the workability and simplicity that are the advantages of the tape method.

Therefore, attempts are being made to use thermosetting resins in the adhesive layer of anticorrosion tapes, but for example, two-component type r(s) that cures at room temperature.
When using a curable resin, its pot life is extremely short, and once curing progresses, it becomes difficult to wrap the tape over and over again, resulting in poor workability and poor heat resistance. It couldn't be called anything.

Furthermore, in the case of heat-curable two-component thermosetting resins, the steel pipe must be heated while being installed, which still causes the above-mentioned difficulties.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is to solve the above-mentioned difficulties of conventional plastic coatings, especially the above-mentioned difficulties of anti-corrosion tape method. The purpose of the present invention is to develop a corrosion prevention method that is effective and does not require a special heating device during its construction.

[Means for solving problems]

This problem is solved by (a) applying an undercoat containing a thermosetting resin composition containing a curing agent that can be cured at room temperature to the surface of the steel material, and (c) coating the plastic film on the plastic film. An inner layer material anticorrosion tape made of a thermosetting resin composition layer containing fiber cloth is wrapped over the tape, and then (d) a base material made of a plastic sheet or a rubber sheet and an adhesive are applied. This is achieved by wrapping the outer layer material tape, which serves as an adhesive layer made of a sticky compound, in layers.

[Function and structure of the invention]

The method of the present invention basically involves performing each of the above steps (a) to (d) in this order. Each of these steps has the following effects.

(Undercoat) 1. The undercoat applied to the surface of the GI material increases the wettability of the thermosetting resin composition layer constituting the inner layer anticorrosion tape to the steel surface and improves the adhesion to the steel surface. .

2. Since it is compatible with the thermosetting resin, the curing agent migrates to the thermosetting resin layer.

3. The thermosetting resin layer can be cured in a short time at least in the vicinity of the steel material by the room temperature curing agent contained in the undercoat.

4. By incorporating a room-temperature curing agent into the undercoat, the inner layer material anticorrosion tape can be stored for a long period of time, and the complexity of the two-component type mixing work during construction can be avoided.

(Inner layer agent anti-corrosion tape) 1. The thermosetting resin layer is cured in a short time at least near the steel material by the curing agent contained in the undercoat that can be cured at room temperature, and the curing progresses further due to the heat of the steel material. Preferably, by blending a one-component type curing agent in the thermosetting resin layer, the thermosetting 4M resin resin can be completely cured by the heat of the steel material, and the anticorrosion performance at high temperatures can be made more effective. shall be.

2. When using epoxy resin as a thermosetting resin, it has high adhesion to steel materials and excellent dimensional stability after curing.
・Exhibits high corrosion resistance. However, thermosetting resins generally have heat resistance, and the 4M resin composition of the inner layer anticorrosion tape is not limited to epoxy resins as long as they have anticorrosion properties at high temperatures.

3. By interposing the resin composition sheet of the inner layer anti-corrosion tape between the steel material and the outer layer anti-corrosion tape, we purposely use a particularly heat-resistant tape as the outer layer anti-corrosion tape in order to improve insulation properties. There's no need to.

4. By cutting plastic fiber cloth or non-woven fabric inside the resin composition sheet, it functions as a support for the inner layer material anticorrosion tape.Furthermore, 5. When the inner layer material anticorrosion tape is wrapped in layers, there is usually considerable wrinkles and misalignment. However, due to the flexibility of the plastic fiber fabric or non-woven fabric, this can be prevented, especially in heated steel materials, as the plastic fiber fabric or non-woven fabric softens. Furthermore, the flexibility is increased, the followability is improved, and wrinkles are less likely to occur when the tape is wound in multiple layers.In addition, it is useful as a support for maintaining the tape properties.

6. The plastic film used as the surface film of the inner layer anti-corrosion tape functions as a release film when it is stored as a tape, and after the thermosetting resin layer has hardened.
It has the function of bonding the inner layer material anticorrosion tape and the outer layer material anticorrosion tape. In particular, an ethylene-acetate-vinyl copolymer film is suitable as this surface film.

(Outer layer material anticorrosion tape) The outer layer material anticorrosion tape is not particularly limited as long as it is an anticorrosion tape consisting of a base material made of a plastic sheet or a rubber sheet and an adhesive layer, and it may be a plastic sheet or a rubber sheet that does not soften under the operating temperature environment. No problem. In general, the anticorrosion tape used as an inner layer protects the pipe from receiving heat from the pipe and provides even better anticorrosion properties.

The method for preventing corrosion of steel materials according to the present invention is as shown in Fig.
The process consists of applying an undercoat (2) to the surface, then wrapping an inner layer material/anticorrosion tape (3) in layers, and further wrapping an outer layer material anticorrosion tape (4) on top of it. However, as shown in Fig. 2, the inner layer anticorrosion tape (3) is composed of a thermosetting resin composition layer (3) containing a plastic fiber cloth (3) formed on a plastic film (3'), and As shown in FIG.
) on which an adhesive compound (4) is formed.

The steel materials (1) to which the undercoat of the present invention can be applied include various metals, such as iron, steel, copper, stainless steel, brass, etc., and the shape of the steel materials is not particularly limited, and various steel materials can be used. Specific examples include pipes, plates, rods, etc., with steel pipes being particularly preferred.

The undercoat of the present invention basically contains as an essential component a curing agent for curing the thermosetting resin composition at room temperature, and usually further contains a curing accelerator, a diluent, and an organic solvent. It is something to do. Preferably, it further contains various other additives such as fillers, softeners, adhesive agents, anti-aging agents, colorants, resin additives, etc., as required.

In this case, a wide range of curing agents can be used that act as curing agents for the thermosetting resin used, and those that are compatible with the resin are particularly preferred. Specifically, for example, if the thermosetting resin composition is an epoxy In the case of resin curable resin compositions,
As the curing agent, a normal curing agent for curing at room temperature that can cure epoxy resin at room temperature is used, and more specifically, polyamide polyamine, aliphatic polyamine, aromatic polyamine,
Examples include alicyclic polyamines. Of course, other curing agents and curing accelerators can also be used, such as acid anhydrides,
Initial condensates of polyamide, sulfide resin, phenol resin, urea resin, melamine resin, etc., tertiary amines containing dicyandiamide and used as a catalyst, boron trifluoride-amine complex, etc. can also be used. These curing agents are used in 1#I or in combination of two or more. Further, triethylamine, pyridine, etc. can be used in the case of a phenol resin-based thermosetting resin composition, and various organic peroxides can be used in the case of an unsaturated polyester resin composition. Furthermore, for resins other than these, a curing agent that can be cured at room temperature may be similarly selected and used as appropriate.

The amount of curing agent blended is 1% by weight or more, preferably 2% by weight or more of the total amount of the undercoat. If the blending amount does not reach 1% by weight, wetting between the steel pipe and the resin composition layer of the inner anticorrosion tape may be insufficient, resulting in a decrease in adhesiveness.

Diluents used in the primer of the present invention include high boiling point solvents such as glycols and esters, plasticizers such as phthalate esters and phosphate esters, non-reactive diluents such as pine oil and coal tar, butyl glycidyl ether, etc. monoepoxy compounds, polyepoxy compounds such as diglycidyl ether, vinyl compounds such as styrene and diallylphthalate,
Epoxidized vinyl monomers such as glycidyl methacrylate-1, etc., reactive diluents such as triphenylfusphite, tetrahydrofuran-A, polyols, and lactones are used.

The blending amount of the diluent is 1 to 100 parts by weight, preferably 5 to 20 parts by weight, per 10 parts by weight of the curing agent.

If the diluent is less than the above-mentioned ratio, the wettability of the inner layer corrosion-resistant tape to the steel material will be insufficient.

Furthermore, if the diluent is larger than the above-mentioned ratio, the inner layer material anticorrosion tape tends to be easily displaced, and since the amount of the hardening agent is relatively small, the inner layer material anticorrosion tape tends to be insufficiently cured.

A wide range of organic solvents are used for the undercoat, including those that can dissolve the hardeners and diluents mentioned above and are compatible with the epoxy resin.For example, toluene, xylene, cyclohexanone, methyl cellosolve, ethyl Select 1f! or two or more from cellosolve, butyl cellosolve, cellosolve acetate, ethyl acetate, methyl ethyl ketone, methyl butyl ketone, dioxane, methylene chloride, acetone, etc., dissolve and disperse the curing agent and diluent, and use as an undercoat solution. The solid content in the undercoat solution is set so that the viscosity is suitable for applying the undercoat solution with a brush, spray, etc., but it is usually preferably about 10 to 50%. The amount is such that the thickness of the undercoat layer after the organic solvent has evaporated is 0.002 to 0.2 mm,
Preferably, it is adjusted to o, o o s to 0.1 ■.

Next, the thermosetting resin composition that forms the inner layer anticorrosion tape contains a thermosetting resin and a curing agent as essential components, and optionally a curing accelerator, filler, softener, adhesion imparting agent, and coloring. agents, thermoplastic resins, rubber, anti-aging agents, etc.

The thermosetting resin mentioned above includes various thermosetting resins such as epoxy resin, unsaturated polyester resin, phenol resin, acrylic resin, silicone resin, and urea resin.
# of such! ) 1 type of curable resin alone or 1! ,°
Use in combination with more than one species.

As the curing agent for the thermosetting resin, a wide variety of commonly known curing agents can be used, and those that are active in the temperature environment in which they are used, and those that can be cured in the temperature range of usually 50 to 150°C, are preferred.

Examples of the above-mentioned curing agents include dicyandiamide, 4,4'-diaminodiphenylsulfone, imidazole derivatives such as 2-n-heptadecyl imidazole, isophthalic acid hydrazide, N,
There are N-dialkyl urea derivatives and the like.

Further, the following various compounds can be added to the thermosetting resin composition as necessary. For example, calcium carbonate, talc, asbestos, silicic acids, carbon blank,
A filler such as colloidal silica is used. The compounding amount is
The amount is usually about O to 300 parts by weight per 100 parts by weight of the thermosetting resin.Furthermore, for the purpose of lowering the viscosity and improving wettability, reactions such as butyl glycidyl ether, monoglycidyl ether of long chain alcohol, etc. A phthalic acid plasticizer such as dioctyl phthalate, a phosphoric acid plasticizer such as triclean diphosphate, etc. can be blended.

The amount of these components is preferably about 0 to 30 parts by weight based on 10,011 parts of the thermosetting resin.

In addition, the plastic fiber cloth embedded in the thermosetting resin layer should preferably be an organic fiber cloth or a non-woven cloth, taking into account the prevention of wrinkles during overlapping, such as nylon, polyester, polypropylene, vinylon, acrylic, etc. , vinyl chloride, polyethylene, etc. are suitable, and the heat distortion temperature is 50~50.
150'e (according to AsTM-0648. Load 18.
6 kg/cd) is preferred. Such plastic fiber cloths are generally more flexible than inorganic metal fibers, and when applied to heated steel materials, it is thought that the flexibility will further increase as the cloth approaches the heat distortion temperature.

These fiber cloths or non-woven fabrics include, for example, plain weave, plain weave, satin weave, twill, leno weave, shabby weave, and cheesecloth, but the best weaving methods are mesh weave, leno weave, and cheesecloth. It is.

Furthermore, by providing the plastic surface film (3') on the resin composition WI (3''), the following effects are brought about.Firstly, the resin composition N<3' having the surface film (3') When ``S is stored as a tape-shaped roll before use, the surface film (3') functions as a separator, and not only does it not cause the problem of glabellar adhesion due to self-fusion, but also prevents corrosion of the inner layer material when heated. It has the effect of adhering the tape and the outer layer material anticorrosion tape.Secondly, after the layer (3) of at least a thermosetting resin, preferably an epoxy resin composition, is wrapped, the surface film (3') is used until it hardens. The surface film (3' ) has the effect of preventing the resin composition in a fluid state from extruding out.

Plasti is an example of such a surface film.

Films such as polyethylene film, nylon film, polyvinyl chloride film, and polypropylene film are preferred, and films of ethylene-vinyl acetate copolymers and derivatives thereof are particularly suitable. The thickness of the film is 0.001~0.5a+m,
Preferably, O.OQ is about 3 to 0.1 mm.

The plastic sheet or rubber sheet used as a support in the outer layer anticorrosion tape of the present invention is mainly made of polyethylene, polypropylene, modified polyolefin, polyamide, polyester, aromatic polyamide, polyether sulfone, polyvinylidene fluoride. , ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, phenoxy resin, butadiene-acrylonitrile rubber, butyl rubber, polyisobutylene rubber, styrene-butadiene rubber, ethylene-propylene rubber, etc. can be used.

It is necessary that the raw material used for the above-mentioned support does not soften under the temperature environment in which it is used. Furthermore, in addition to the above raw materials, various additives such as colorants, antioxidants, fillers, etc. can be blended as necessary. Further, the thickness of the support is usually 5 to 1000 .mu.m, preferably 10 to 600 .mu.m in order to ensure flexibility as a tape.

As the adhesive compound, any conventionally used adhesive compound can be used, and a compound mainly composed of commonly used rubber components is preferable. Specific examples include natural rubber, polyisobutylene rubber, butyl rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber, halogenated rubber, nitrile rubber, and modified products thereof. Furthermore, if necessary, various other additives such as fillers, softeners,
Adhesive agents, anti-aging agents, colorants, etc. can be added as appropriate.

Further, glass cloth, glass nonwoven fabric, or synthetic fiber cloth or nonwoven fabric with excellent heat resistance can be incorporated in the support layer. Further, if necessary, the support layer can have a multi-N structure.

For convenience, the method of carrying out the method of the present invention will be explained below using a steel pipe. First, the outer surface of the steel pipe to be constructed is subjected to rust removal and surface conditioning using blasting, sandpaper, etc. as necessary. Next, apply the undercoat by appropriate means such as brushing or spraying until the thickness of the organic solvent after volatilization is 0.002 to 0.2.
The coating is applied so that the thickness is preferably 0.005 to 0.1 +*+m. If the amount of the undercoat applied is too small, it is not preferable because it causes a decrease in wetting and a decrease in adhesion at the interface between the steel pipe and the thermosetting resin composition layer of the inner layer anticorrosion tape. Additionally, if the amount of primer applied is too large, unreacted curing agent will remain at the interface between the steel pipe and the resin layer, reducing adhesion, no matter how compatible the curing agent is with the thermosetting resin. , undesirable.

Next, before the organic solvent of the undercoat evaporates, quickly wrap the inner layer material anticorrosion tape in a spiral shape, starting from the beginning of the 0th wrap, and temporarily fixing the ends with heat-resistant tape such as fluororesin tape. Preferably, the outer layer anti-corrosion tape is wound in layers in the same manner.

In addition, in cases where a large external force is applied, such as when buried underground, a protective tape should be wrapped around the outside of the above-mentioned tape (this will ensure more complete anti-corrosion performance. It is preferable that the support is a plastic sheet or a rubber sheet having a high elastic modulus within a range that can be handled as a tape, and the adhesive layer thereof is preferably an adhesive compound mainly composed of non-polar rubber.The protective tape is At least until the adhesive layer of the anticorrosive tape of the present invention hardens, the tape is protected from external forces such as earth pressure and stones, and has the effect of preventing tape displacement and wrinkles.

〔Example〕

The present invention will be explained below with reference to Examples. However, in the following examples, parts indicate parts by weight.

Example 1 2.4.6-dimethylaminomethylphenol・・・・・・・・・・・・・・・・・・
・・・・・・lO part di-n-octyl phthalate...
・・・・・・・・・45 parts Methyl ethyl ketone・・・・
・・・・・・・・・・・・・・・45 Department Works'' Yod
Sea A Bisphenol A type epoxy resin (i390 per epoxy)...60.6 parts Talc...................................................................................................
・・・・・・30. Part 3 Ashest・・・・・・・・・
・・・・・・・・・・・・・・・6.06 parts Dicyandiamide curing agent・・・・・・・・・3.03 parts 0.5 mm epoxy resin sheet with the above formulation 0.07 to
■Polyester cloth (number of vertical and horizontal fibers: 20/inch each, density: 35 g/m, heat distortion temperature: 85
℃ ASTM-D648 (18.6 kg/-) and further 0.05 mm thick EVA (ethylene-vinyl acetate copolymer, vinyl acetate 14% by weight, softening point 61℃)
) The films were laminated to form a roll of anticorrosion tape for the inner layer material.

Sand the surface of a steel pipe with an outer diameter of 50 am with sandpaper (#240).
), the undercoat solution was spray applied so that the thickness of the undercoat layer after evaporation of the solvent was approximately 0.02 m+m, and the above-mentioned inner layer material anticorrosion tape was wrapped in a half ramp. At that time, there was no problem of glabellar adhesion due to self-fusion of the wound body of the inner layer material anticorrosion tape (and the overlapping winding on the steel pipe was also possible smoothly without any problems such as wrinkles).

Next, natural rubber was placed on a 0.2 mm thick polyethylene sheet.
0 adhesive compounds consisting of softeners and tackifiers
．． An anticorrosion tape coated to a thickness of 2+sm was wrapped half-wrap to form a coated steel pipe.

This anti-corrosion treated steel pipe was left at 40° C. for 20 hours to volatilize the solvent and harden it. At this time, the inner layer anti-corrosion tape was hardened and could not be removed from the steel pipe.

Comparative Example 1 In Example 1, an anti-corrosion treated steel pipe was obtained by wrapping the anti-corrosion tape in layers without applying the primer solution.

At that time, the inner layer material anticorrosion tape could be peeled off at the interface with Sat.

Comparative Example 2 In Example 1, a wound body of the inner layer material anticorrosive tape was obtained without laminating the EVA film. In this case, when overlapping the steel pipe, the anticorrosion tape for the inner layer was fused between the eyebrows, making it impossible to overwrap and evaluate the corrosion protection test.

Comparative Example 3 In Example 1, the inner layer anticorrosion tape was made without impregnating the polyester cloth. In this case, when wrapping the steel pipe over and over, no tension was applied and the anticorrosion tape for the inner layer stretched, and when the tape was wrapped loosely around the steel pipe, air got mixed in between the steel pipe and the tape.

Comparative Example 4 In Example 1, instead of the polyester cloth, glass cloth was impregnated to prepare an inner layer material anticorrosion tape.

In this case, when wrapping the steel pipe in layers, the inner layer material should be protected against corrosion.
- There were wrinkles in the roll, and it was not possible to wrap it in layers so that it looked good.

The coated pipes of the above examples and comparative examples were heated at 40℃ for 2 hours.
After standing for 0 hours, the following tests were conducted and the results shown in Table 1 were obtained.

(1) Hot water test Two coated steel pipes were immersed in boiling water at 100°C for 20 days, and then the occurrence of blistering in the coating was observed, and the occurrence of pinholes was confirmed using an ACIOKV pinhole tester.

(2) Burial test: Heat-resistant and pressure-resistant hoses are attached to both ends of the steel pipe so that heat transfer oil can flow into the coated steel pipe, and after burying the pipe 1 meter underground, heat transfer oil at 100°C is applied at a flow rate of 10001/min. After continuing to flow for 20 days, the steel pipe to be subjected to ri was taken out and returned to room temperature, and changes in appearance such as swelling and wrinkles of the coating were observed.

Table 1

[Brief explanation of drawings]

Fig. 1 shows a corrosion-resistant steel material constructed by the method of the present invention, Fig. 2 shows an anti-corrosion tape for the inner layer material used in the method of the present invention, and Fig. 3 similarly shows a corrosion-proof tape for the outer layer material. (1)...Steel material (2)...Undercoat layer (3)...Inner layer material anti-corrosion tape (4)...Outer layer material anti-corrosion tape ( 3')...
...Plastic film (3') ...Plastic fiber cloth (3) ...Thermosetting resin composition layer (4) ...Base material serving as support (4 )... Adhesive compound layer (or more) Patent applicant: Nitto Electric Industry Co., Ltd. Day

Claims (4)

[Claims] (1) (a) Apply an undercoat containing a hardening agent that can cure a thermosetting resin composition at room temperature to the surface of the steel material, (b) apply a plastic fiber cloth on the plastic film, and An inner layer anti-corrosion tape made of a thermosetting resin composition contained inside is wrapped, and then (d) a base material made of a plastic or rubber sheet and an adhesive made of an adhesive compound are wrapped. A method for preventing corrosion of steel materials, which is characterized by wrapping outer layer material tapes in layers. (2) The method for preventing corrosion of steel materials according to claim 1, wherein the plastic film constituting the inner layer material anticorrosion tape is an ethylene-vinyl acetate copolymer film. (3) The method for preventing corrosion of steel materials according to claim 1, wherein the thermosetting resin composition layer constituting the inner layer material anticorrosion tape is an adhesive layer made of a thermosetting resin composition containing a hardening agent. . (4) The corrosion prevention method according to claim 1, wherein the thermosetting resin has an epoxy resin as a main component.