JP4738131B2 - Corrosion protection method - Google Patents

Description

  The present invention relates to a method for coating corrosion protection on the surface of an object to be protected, and in particular, maintains good adhesion not only in the air but also in a wet state or a concrete surface including a reinforcing bar in a water surface, and their corrosion. TECHNICAL FIELD The present invention relates to a coating anticorrosion method for preventing the corrosion over a long period of time.

  As a conventional method for preventing corrosion of the surface of the object to be protected, there are generally painting, lining, concrete coating, petrolatum lining, plating, etc., and many documents are shown (for example, refer to Non-Patent Document 1). Among the anticorrosion methods in the outdoors, the corrosion method of the surface of the object to be protected in water, repeated dry and wet conditions, which is particularly severe as a corrosive environment, or in a high humidity, is a very limited method among the above corrosion and corrosion methods ( For example, refer nonpatent literature 2). Moreover, as an anticorrosion method with respect to the metal which has been exposed to these environments and has already caused corrosion, underwater coating (for example, refer to Patent Document 1 and Patent Document 2), petrolatum lining (for example, refer to Patent Document 3) And concrete coating (see, for example, Patent Document 4).

  Moreover, as an anticorrosion method using a material containing a water-absorbing polymer, there is an anticorrosion structure in which a water-absorbing polymer added to a rubber material is attached to a protective material (see, for example, Patent Document 5).

  Further, as an anticorrosion method using an uncured resin, there is a lining method (see, for example, Patent Document 6) in which a urethane resin or an epoxy resin is impregnated into a nonwoven fabric and attached.

  Further, there has been proposed an anticorrosion processing method (see, for example, Patent Document 7) in which a fluid resin is poured into a mold that has been assembled with a certain gap around the body to be protected.

  Among the above-described corrosion prevention methods, the above three methods mentioned as the corrosion prevention methods for existing structures in particularly severe corrosive environments have the following problems.

  (1) Underwater coating: Surface treatment by blasting is required (SIS-Sa2 or higher) and must be applied immediately after the surface treatment. Actually, partial adhesion failure or peeling due to subtle differences in on-site processes. May occur. Some underwater putty increases the film thickness, but has similar problems. Usually, since a protective layer is not provided on the surface of the coating film, it is directly affected by environmental changes and external forces, and therefore there is a problem in terms of life.

  (2) Petrolatum lining: Petrolatum is an excellent anti-corrosion material and exhibits good anti-corrosion effect even with a relatively low grade base treatment (SIS-St2). Adhesion is not possible although it shows the property. Accordingly, in an environment where external force is applied, there is a possibility that a gap is generated between the corrosion-protected body and the corrosion-proof layer in the long term, and corrosion may occur.

  (3) Concrete coating: Concrete is a material that exhibits alkalinity and is excellent as a material that blocks moisture and dissolved oxygen from the environment and prevents corrosion, but it is generally difficult to apply and protect in environments with a lot of moisture. It is widely practiced to assemble a mold with a certain gap in the body to be protected and pour it into it to fill and coat it. However, in this case, it is difficult to completely fill the gap in the mold even in the recent progress of dispersion inhibitors. Further, with this method, fine work adapted to the shape of the body to be protected is almost impossible, and as a result, a coating body having a considerable weight is obtained. This becomes a big load to a to-be-protected body. In the long term, the neutralization of concrete occurs due to salt infiltration, etc., and even if partial corrosion occurs, the concrete layer may suddenly crack and fall off due to the expansion pressure of rust. In addition, since concrete is a material that has almost no elasticity, even if the corrosion protection material moves slightly due to external force or heat change, it cannot follow the movement. Therefore, even if the concrete and the surface to be protected are in close contact with each other at the beginning of the construction, they peel off over time, causing corrosion. In particular, this phenomenon is observed in offshore structures.

  In addition, anti-corrosion by coating with a water-absorbing polymer added to a rubber material can provide excellent water-proofing and anti-corrosion for metal with a smooth surface, but actual structures are often used during corrosion and construction. There are many irregular irregularities due to welding traces. In this case, the water swelling of the already cured rubber material is insufficient to maintain the adhesion, and a good anticorrosive effect cannot be obtained.

  The method of impregnating and pasting the uncured resin into the non-woven fabric is difficult to remove the moisture in the coating in a corrosive environment such as the marine environment, so that a resin adhesion failure is likely to occur and a good corrosion coating cannot be achieved. Moreover, since the strength of the coating layer is weak, long-term corrosion protection is difficult.

  The method of pouring a fluid resin into a mold and covering it is effective for the surface of the body to be corroded and smooth in the atmosphere, but adhesion between the surface of the body to be corroded and the resin is not possible in a wet state. In particular, when a part of the resin is in water, the specific gravity, viscosity, etc. of the resin greatly affect the dispersion in the mold and it is difficult to obtain good and stable corrosion protection.

  On the other hand, the present inventors have proposed a coating anticorrosion method using an organic material on the surface of the object to be protected (see Patent Document 8 below). This method is characterized in that the surface of the body to be protected is covered with an uncured resin containing a water-absorbing polymer.

  By the way, the coating anticorrosion method is often applied at a setting place of an existing structure which is difficult to work, and is often applied to an anticorrosive body having irregular irregularities on the surface. For this reason, the technique which can perform corrosion prevention stably with respect to such a to-be-protected body surface, and can perform construction efficiently was desired.

JP-A-2-248532 Japanese Utility Model Publication No. 61-66043 JP-A-62-1830 Japanese Patent Publication No. 5-45728 JP-A-62-78323 JP-A-3-218815 JP 60-144427 A Japanese Patent No. 3449559 Corrosion and Corrosion Prevention Handbook, Nobuo Suzuki, Corrosion and Corrosion Protection Association, 2000, p436-461 Port Steel Structure Corrosion Prevention and Repair Manual, Coastal Development Technology Research Center, 1997, p109-113

  Therefore, the object of the present invention is to solve the problems of these conventional methods, and not only for new facilities, but also for structures that are in a corrosive environment underwater or in a wet state. And it is providing the coating anticorrosion method which maintains the stable anticorrosion state and is excellent also in the construction property on the spot.

The present invention provides a coating and anticorrosion method in which the surface of an object to be protected is coated to prevent corrosion, the surface of the object to be protected is coated with a resin foam material, the outside of the resin foam material is protected with a protective material, and the resin The object is achieved by providing a coating anticorrosion method characterized by blending a water-absorbing polymer into a foam material or coating the resin foam material with a water-absorbing polymer .
In addition, the present invention provides a coating and anticorrosion method that coats and protects the surface of an anticorrosive body, covers the surface of the anticorrosive body with a resin foam material, protects the outside of the resin foam material with a protective material, The object is achieved by providing a coating anticorrosion method characterized in that a resin layer having adhesiveness or tackiness is interposed between the resin foam material and the protective material.
In addition, the present invention provides a coating and anticorrosion method that coats and protects the surface of an anticorrosive body, covers the surface of the anticorrosive body with a resin foam material, protects the outside of the resin foam material with a protective material, The object is achieved by providing a coating anticorrosion method characterized by interposing an adhesive layer between the object to be protected and the resin foam material.
In addition, the present invention provides a coating and anticorrosion method that coats and protects the surface of an anticorrosive body, covers the surface of the anticorrosive body with a resin foam material, protects the outside of the resin foam material with a protective material, The object is achieved by providing a coating anticorrosion method characterized by interposing a water-impervious sheet between the anticorrosive body and the resin foam material.

  According to the present invention, not only a new facility but also a structure in a corrosive environment underwater or in a wet state, a good and stable anticorrosion state is maintained over a long period of time, and the workability on site is improved. An excellent coating anticorrosion method is also provided.

  Hereinafter, the coating anticorrosion method of the present invention will be described based on preferred embodiments thereof.

  As shown in FIG. 1, the coating anticorrosion method of this embodiment is a method of covering and protecting the surface of the body 1 to be corroded, and covering the surface of the body 1 to be coated with the resin foam material 2. The outside of 2 is protected by a protective material 3. Here, as the to-be-corroded body 1, concrete, such as metals, such as iron, stainless steel, zinc, and aluminum, and a reinforcing bar, is mentioned.

  In the coating anticorrosion method of this embodiment, first, the surface of the body 1 to be protected is prepared, and the surface of the body 1 to which the base has been adjusted is coated with the resin foam material 2. For the substrate adjustment, it is preferable to perform conventional substrate adjustment in accordance with the body 1 to be protected.

  In this embodiment, the adhesive layer 4 is interposed between the surface of the corrosion-protected body 1 and the resin foam material 2 so that the resin foam material 2 is in close contact with the corrosion-protected body 1. The adhesive layer 4 also functions as a lubricant for performing necessary fine adjustment when the resin foam material 2 is attached to the surface of the body 1 to be protected.

  For the adhesive layer 4, a sticky or adhesive primer conventionally employed in this type of coating anticorrosion can be used without particular limitation. Examples of the primer include urethane, acrylic, butyl rubber, silicone, and propylene resins.

  The resin foam material 2 includes closed or open cells, and is preferably formed of one or more resins selected from polyurethane resins, rubber resins, polystyrene resins, and polyethylene resins.

  The resin foam material 2 improves the adhesion between the corroded body 1 and the resin foam material 2 by absorbing moisture present on the surface of the corroded body 1 and blocks the environment by the water absorption swelling of the resin foam material 2. From the viewpoint of reducing the diffusion of water and oxygen, it is preferable to mix a water-absorbing polymer or coat with a water-absorbing polymer.

  The water-absorbing polymer includes polyacrylate resin, polyalkylene oxide resin, polyethylene oxide resin, polyvinyl alcohol (PVOH) resin, poly N-vinylacetamide (PNVA) resin, vinyl acetate / acrylic acid ester One or more resins selected from copolymer saponified products, polyvinyl acetate / maleic anhydride reactants, isobutylene / maleic acid cross-linked products, and starch / acrylic acid graft polymers are preferred. When the water contains a large amount of electrolyte, nonionic water-absorbing polymers such as polyvinyl alcohol resins and poly N-vinylacetamide are preferable.

  The water-absorbing polymer is 1 to 100 weights with respect to 100 parts by weight of the resin foam material in consideration of the absorbability of moisture existing on the surface of the body 1 to be protected and the adhesion between the body 1 and the resin foam material 2. It is preferable to add at 5 to 50 parts by weight. In addition, when the resin foam material 2 is swollen with water, the water-absorbing polymer is granular and uniformly dispersed so that the bubble portion of the resin foam material 2 disappears and functions as a stable shielding layer. preferable.

  The resin foam material 2 is coated with the water absorbent polymer by directly mixing the water absorbent polymer with the raw material of the resin foam material 2 for foaming or molding, or by impregnating the resin foam material with the water absorbent polymer dissolved in the solvent. To do.

  The resin foam material 2 preferably has an expansion ratio of 5 to 50 times, particularly 10 to 40 times in consideration of adhesion to the surface of the body 1 to be protected, ease of construction, and workability.

  In this embodiment, the water-impervious sheet 5 is interposed between the to-be-corroded body 1 and the resin foam material 2, whereby corrosion due to intrusion of moisture can be further suppressed. In the case of interposing the adhesive layer 4, a water shielding sheet 5 can be attached to the surface of the resin foam material 2, and a primer can be applied to the surface of the water shielding sheet 5 as the adhesive layer 4. The adhesive layer 4 can be formed by applying a primer in advance to the surface of the body 1 to be protected, and the adhesiveness with the resin foam material 2 can be further stabilized.

  Examples of the water-impervious sheet 5 include sheets made of butyl or silicone rubber. The water-impervious sheet 5 captures and swells water that the sheet itself has entered from the outside from the viewpoint of blocking moisture and oxygen from entering from the outside, and the resin foam material 2 is compressed by the swelling so that it is difficult for water to pass through. From this viewpoint, a sheet having swelling property is preferable, and from this viewpoint, a sheet having water swelling property is preferable. Further, the water-impervious sheet 5 is rich in flexibility and extensibility so that no gap is formed between the surface of the corrosion-protected body 1 when the present invention is applied to a corrugated corrosion-resistant body. preferable.

  As the protective material 3, those conventionally used for this type of coating anticorrosion protective material can be used. Preferred protective materials include fiber reinforced plastics or those made of corrosion resistant metals such as titanium and stainless steel.

  In the present embodiment, a resin layer 6 having adhesiveness or tackiness is interposed between the resin foam material 2 and the protective material 3 from the viewpoint of achieving close contact and integration. The resin layer 6 is preferably one or more resins selected from butyl resins and acrylic resins.

  It is preferable to add a rust preventive agent to the resin foam material 2, the adhesive layer 4, or the resin layer 6 from the viewpoint of further enhancing the anticorrosive effect of the body 1 to be protected. The rust inhibitor is preferably one or more rust inhibitors selected from tannates, phosphates, nitrites, sulfites, and metallic zinc.

  In the coating anticorrosion method of this embodiment, the resin foam material 2 and the protective material 3, preferably the resin layer 6 and / or the water-impervious sheet 5 are integrally laminated in advance from the viewpoint of ease of construction and shortening of construction time. It is preferable to provide a composite that has been prepared, and this composite is bonded directly to the surface of the body 1 to which the base material has been adjusted, preferably after applying a primer, preferably as the adhesive layer 4.

  As described above, the coating anticorrosion method of the present embodiment covers the surface of the body 1 to be protected with the resin foam material 2 as described above, and further protects the outside of the resin foam material 2 with the protective material 3. Even when the surface of the body 1 to be corroded has irregular uneven portions, the resin foam material 2 can be deformed so as to follow the uneven portions and can be covered in close contact with the surface. Therefore, a good and stable anticorrosion state can be maintained over a long period of time. In addition, the resin foam material 2 is mixed with a water-absorbing polymer or coated with the water-absorbing polymer, thereby promoting the absorption of moisture on the surface of the corrosion-protected body 1, and the resin foam material 2 on the surface of the corrosion-protected body 1. It is possible to improve the adhesion. Moreover, since the resin foam material 2 should just be stuck and the outer side should just be covered with the protective material 3, the construction work on the spot is also easy to perform, and work can be advanced efficiently.

  The present invention is not limited to the embodiment.

Hereinafter, the present invention will be described more specifically with reference to examples.
Test specimens were prepared as in Examples 1 to 6 below, and each specimen was subjected to a salt spray test for 500 hours, 1000 hours, or 2000 hours in accordance with JIS K5600 7-1 to prevent corrosion of the object to be protected. The rate was calculated to evaluate the anticorrosion performance.

[Example 1] (Protective body + resin foam material + protective material)
The edge of a polished steel plate (SS400) having a thickness of 1.2 mm, a width of 70 mm, and a length of 150 mm was polished using # 400 emery paper, and the surface degreased with acetone was used as a test piece 10 for an anticorrosive body. The mass was weighed to the nearest 0.1 mg. Next, as shown in FIG. 2, PVC linear bodies 11 and 12 having a length of 160 mm and a cross section of an isosceles triangle having a cross section of 5 × 5 mm, a height of 3 mm, and a base of 5 mm are formed on the test piece 10. After affixing each on one side with an adhesive, urethane-based foam material 20 (manufactured by Nittobo Ecology, expansion ratio 40 times) was superposed and adhered to the outside. Then, a PVC 30 plate 30 (manufactured by Nitto Boseki Co., Ltd.) is superimposed on the outside of the foam material 20 as a protective material, and the test piece 10 is sandwiched between the foam material 20 and the PVC plate 30 so as to make the PVC product. The plates 30 were fastened and fixed with bolts (not shown) to obtain test specimens.

[Example 2] (Corrosion protected body + resin foam material + protective material)
A specimen was prepared in the same manner as in Example 1 except that a rubber-based foam material (manufactured by Nittobo Ecology, foaming ratio: 13 times) was used in place of the urethane-based foam material of Example 1.

[Example 3] (Corrosion protected body + adhesive layer + resin foam material + protective material)
Tested in the same manner as in Example 1 except that an adhesive primer (butyl rubber) was applied to the surface of the object to be protected and an adhesive layer was interposed between the object to be protected and the resin foam material. The body was made.

[Example 4] (Corrosion protected body + adhesive layer + water-absorbing polymer-added resin foam material + protective material)
A test specimen was prepared in the same manner as in Example 3 except that 40% by weight of a polyacrylate water-absorbing polymer was added to the resin foam material of Example 1.

[Example 5] (Corrosion protected body + adhesive layer + water-proof sheet + resin foam material + protective material)
A test specimen was prepared in the same manner as in Example 3 except that a butyl rubber water-proof sheet (thickness: 0.1 mm) was interposed between the resin foam material and the adhesive layer.

[Example 6] (Corrosion protected body + rust preventive addition adhesive layer + resin foam material + protective material)
A test specimen was prepared in the same manner as in Example 3 except that 5 wt% of a tannate anticorrosive was added to the primer.

[Comparative Example 1]
As a non-corrosive test specimen, a test specimen was prepared in the same manner as in Example 1 except that the resin foam material and the PVC plate were not superimposed on the surface of the anti-corrosive body.

[Calculation method of anticorrosion rate]
Anticorrosion rate (%) =
((Weight reduction of the corrosion-resistant body of Comparative Example 1) − (weight reduction of the corrosion-resistant body of each Example)) × 100 / (weight reduction of the corrosion-resistant body of Comparative Example 1)

  As shown in Table 1, it was found that high anticorrosion properties were obtained in any of the anticorrosion methods of Examples 1-6. Moreover, the following could be confirmed from consideration of these Examples. 1) From comparison between Example 1 and Example 3, urethane foam material is more excellent in corrosion resistance than rubber foam material. 2) From the comparison between Example 1 and Example 3, the corrosion resistance is improved when a primer is interposed between the body to be protected and the foam material. 3) From the comparison between Example 1 and Example 4, the addition of a water-absorbing polymer to the foam material improves the corrosion resistance. 4) From the comparison between Example 3 and Example 5, when a water-impervious sheet is interposed between the body to be protected and the foam material, the corrosion resistance is improved. From the comparison between Example 3 and Example 6, the addition of a rust inhibitor to the primer improves the corrosion resistance.

It is sectional drawing which shows typically the anticorrosion structure by the coating | coated anticorrosion method of this invention. It is a figure which shows the structure of the test body used for an anticorrosion test in an Example, (a) is a longitudinal cross-sectional view, (b) is a front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Corrosion object 2 Resin foam material 3 Protective material 4 Adhesive layer 5 Water-proof sheet 6 Resin layer

Claims (10)

In the coating anticorrosion method of covering the surface of the body to be protected and preventing corrosion,
The surface of the body to be protected is covered with a resin foam material, and the outside of the resin foam material is protected with a protective material, and the resin foam material is mixed with a water absorbent polymer or the resin foam material is made of a water absorbent polymer. coating anticorrosive wherein the coating. The water-absorbing polymer, polyacrylate resins, polyalkylene Oki shea de resins, polyethylene oxide resins, polyvinyl alcohol resins, poly N- vinylacetamide-based resin, vinyl acetate-acrylic acid ester copolymer saponified And one or more resins selected from polyvinyl acetate / maleic anhydride reactant, isobutylene / maleic acid reactant, and starch / acrylic acid graft polymer, and the blending amount or coating amount of the water-absorbing polymer is the resin. coating corrosion process according to claim 1, wherein relative to foam 100 parts by weight of 1 to 100 parts by weight. A rust inhibitor is added to the resin foam material, and the rust inhibitor is one or more rust inhibitors selected from tannate, phosphate, nitrite, sulfite, and metal zinc powder. The coating anticorrosion method according to claim 1 or 2 . In the coating anticorrosion method of covering the surface of the body to be protected and preventing corrosion,
The surface of the body to be protected is coated with a resin foam material, the outside of the resin foam material is protected with a protective material, and a resin layer having adhesiveness or adhesiveness is provided between the resin foam material and the protective material. The coating anticorrosion method characterized by interposing . The coating anticorrosion method according to claim 4 , wherein the resin layer is made of one or more resins selected from a butyl resin and an acrylic resin. A rust inhibitor is added to the resin foam material or the resin layer, and the rust inhibitor is one or more selected from tannate, phosphate, nitrite, sulfite, and metal zinc powder The coating anticorrosion method according to claim 4, which is a rust inhibitor . In the coating anticorrosion method of covering the surface of the body to be protected and preventing corrosion,
Covering the surface of the object to be protected with a resin foam material, protecting the outside of the resin foam material with a protective material, and interposing an adhesive layer between the object to be protected and the resin foam material A coating anticorrosion method characterized by the above. A rust preventive is added to the resin foam material or the adhesive layer, and the rust preventive is selected from tannate, phosphate, nitrite, sulfite, and metallic zinc powder. The coating anticorrosion method according to claim 7, which is one or more rust preventives . In the coating anticorrosion method of covering the surface of the body to be protected and preventing corrosion,
The surface of the corrosion-resistant body is covered with a resin foam material, the outside of the resin foam material is protected with a protective material, and a water-impervious sheet is interposed between the corrosion- protected body and the resin foam material. Coating anticorrosion method. A rust inhibitor is added to the resin foam material, and the rust inhibitor is one or more rust inhibitors selected from tannate, phosphate, nitrite, sulfite, and metal zinc powder. The coating anticorrosion method according to claim 9 .

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