WO2024105867A1 - 金属材における防食被覆層の損傷の補修方法 - Google Patents

金属材における防食被覆層の損傷の補修方法 Download PDF

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Publication number
WO2024105867A1
WO2024105867A1 PCT/JP2022/042788 JP2022042788W WO2024105867A1 WO 2024105867 A1 WO2024105867 A1 WO 2024105867A1 JP 2022042788 W JP2022042788 W JP 2022042788W WO 2024105867 A1 WO2024105867 A1 WO 2024105867A1
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Prior art keywords
sheet
coating layer
filling
polyolefin
corrosion
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PCT/JP2022/042788
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English (en)
French (fr)
Japanese (ja)
Inventor
修也 長谷川
勇 梅田
盛男 岩本
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Dai Ichi High Frequency Co Ltd
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Dai Ichi High Frequency Co Ltd
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Application filed by Dai Ichi High Frequency Co Ltd filed Critical Dai Ichi High Frequency Co Ltd
Priority to CN202280101232.9A priority Critical patent/CN120076927A/zh
Priority to PCT/JP2022/042788 priority patent/WO2024105867A1/ja
Priority to JP2023514873A priority patent/JP7268262B1/ja
Publication of WO2024105867A1 publication Critical patent/WO2024105867A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B43/00—Operations specially adapted for layered products and not otherwise provided for, e.g. repairing; Apparatus therefor

Definitions

  • the present invention relates to a method for repairing damage to a corrosion-resistant coating layer on a metal material coated with the coating layer, the coating layer being made of polyolefin.
  • Polyolefins are easy to process and have excellent resistance to moisture, soil, gas, etc., so they are widely used as anti-corrosion coatings for metal materials such as steel pipes.
  • Metal materials are subjected to various physical shocks during storage, transportation, installation, etc., and the corrosion-resistant coating layer of metal materials coated with polyolefin for corrosion protection may be damaged during such shocks. Damage can cause the corrosion protection properties of the polyolefin to decrease, so when damage occurs, it is necessary to repair it.
  • Various methods for repairing the damage have been proposed.
  • Patent Documents 1 to 3 there are several known methods for filling exposed areas of the corrosion protection coating with a filler (sealant) (Patent Documents 1 to 3).
  • Patent Document 1 discloses a repair method in which a damaged area formed as a recess in a corrosion-resistant coating layer is filled with a sealant that is heat-fusible or adhesive and fluid at room temperature, so that its upper surface is at the same level as the surface of the corrosion-resistant coating layer, and then a repair member consisting of a cross-linked polyolefin sheet with an adhesive layer on one side is heat-pressed to the damaged area of the corrosion-resistant coating layer via the adhesive layer so as to cover the corrosion-resistant coating layer surrounding the damaged area as well, and then a reinforcing heat-fusible polyolefin sheet that has a softening point higher than that of the adhesive used in the adhesive layer of the repair member is heat-pressed to cover at least the outer periphery of the repair member and the corrosion-resistant coating layer adjacent to the outer periphery continuously.
  • a sealant that is heat-fusible or adhesive and fluid at room temperature
  • Patent Document 2 discloses a repair method in which a filler is filled into damaged areas of the coating of polyethylene-coated corrosion-resistant steel material, a polyethylene sheet is placed over the filler, and the polyethylene sheet is ultrasonically welded to the polyethylene coating on the surface of the steel material.
  • Patent Document 3 discloses a repair method in which a primer containing a reactive curing resin that exhibits adhesion to polyolefins is applied to at least the surface of a polyolefin corrosion protection coating layer around the exposed surface of a steel pipe that is intended to come into contact with a sealant, a sealant containing a reactive curing resin that exhibits adhesion to a steel pipe is then applied to the surface intended to come into contact with the sealant and the exposed surface of the steel pipe, and a heat-shrinkable coating material with a primer applied to one side is then placed on at least the sealant layer so that the primer-coated surface faces the sealant layer, and the heat-shrinkable coating material is heated and heat-shrunk while being pressed onto at least the sealant layer at the latest before the completion of the curing reaction of the primer.
  • Patent Documents 4 and 5 a method for repairing exposed areas of the anticorrosive coating layer using a polyolefin sheet.
  • Patent Document 4 discloses a repair method in which a modified polyethylene sheet is heated and pressed onto the damaged area of the mill-coated polyethylene coating layer of steel and onto the surface of the coating layer surrounding the damaged area, and then a two-layer sheet (lower layer: modified polyethylene, upper layer: polyethylene) is heated and pressed onto the modified polyethylene coating layer to cover it.
  • Patent Document 5 discloses a repair method in which a primer containing an organometallic compound is applied to the damaged area of polyolefin-coated steel and the surrounding mill-coated polyolefin coating layer, the primer is applied to one side and both sides of a repair polyolefin sheet shaped to be inserted into the damaged area, and then an ⁇ -cyanoacrylate resin composition is applied to at least one of the primer-coated surfaces of the damaged area and the surrounding mill-coated polyolefin coating layer and the primer-coated surface of the repair polyolefin sheet, with the primer-coated surfaces facing each other and the repair polyolefin sheet adhered to the damaged area.
  • Metal materials repaired using methods that use a filler (sealant) as described in Patent Documents 1 to 3 have a structure in which different materials (filler and polyolefin) are bonded together. Therefore, in an environment in which the temperature around the metal material may rise, there is a concern that the repaired area may be damaged due to differences in thermal expansion coefficients. Furthermore, in the case of the methods using polyolefin sheets as described in Patent Documents 4 and 5, there are drawbacks such as the need for heating or the need for special materials as adhesives or primers to ensure sufficient adhesion between the polyolefin sheet and the underlying metal material or the surrounding polyolefin corrosion-resistant coating layer.
  • Japanese Patent Application Laid-Open No. 61-170586 JP 2001-129892 A Japanese Patent Application Laid-Open No. 61-193832 Japanese Patent Application Laid-Open No. 1-95029 Japanese Patent Application Laid-Open No. 1-275032
  • the present invention has been made in consideration of the above-mentioned background technology, and its objective is to provide a repair method that can easily repair damage to a corrosion-resistant coating layer on a metal material (e.g., repairs can be made even by unskilled personnel) and that produces repaired parts with excellent stability and durability.
  • the present inventors have found that when repairing a corrosion-protective coating layer by filling the removed coating area with a polyolefin sheet made of the same material as the corrosion-protective coating layer, uniform adhesion can be achieved by laminating and adhering the polyolefin sheets in two or more sheet layers, and each sheet layer being constructed by joining multiple polyolefin sheets.
  • the present invention provides a method for repairing damage to a corrosion-resistant coating layer of a metal material coated with the corrosion-resistant coating layer made of a polyolefin, comprising the steps of: a coating removal portion forming step of forming a coating removal portion in which the metal material is exposed by removing the damaged portion of the corrosion-resistant coating layer and the raised portion around the damaged portion; and
  • the method includes at least a filling portion forming step of laminating and adhering two or more sheet layers of a filling polyolefin sheet to the coating removal portion to form a filling portion having approximately the same height as the anticorrosive coating layer surrounding the coating removal portion,
  • the repair method is characterized in that each of the sheet layers has a seam line formed by joining a plurality of filling polyolefin sheets, and the seam lines of adjacent sheet layers are prevented from overlapping.
  • the present invention also provides the above-mentioned repair method, which further includes a cover forming step of forming a cover that covers the boundary between the filling portion and the corrosion-resistant coating layer that surrounds the filling portion by adhering a covering polyolefin sheet to the boundary.
  • polyolefin sheet may be abbreviated as “sheet,” “filling polyolefin sheet” as “filling sheet,” and “cover polyolefin sheet” as “cover sheet.”
  • damage to a corrosion-protective coating layer in a metal material can be repaired in a simple manner, and a repair method can be provided in which the repaired portion has excellent stability and durability.
  • metal materials such as steel pipes to which the present invention is applied are often used in locations with high moisture or in environments where they are exposed to chemicals, but metal materials repaired using the method of the present invention can demonstrate sufficient durability even in such locations.
  • the method of the present invention does not require heating when attaching the polyolefin sheet to metal materials, so repairs can be made even in places and situations where open flames must be avoided.
  • the sheet filled in the area where the coating was removed and the anticorrosive coating layer remaining around the area where the coating was removed are made of the same polyolefin, so the thermal expansion coefficients of both are roughly the same, and the repaired area is less likely to be damaged even in an environment where the temperature around the metal material may rise.
  • the sheet layer is made up of multiple sheets joined together, so the size of each sheet is relatively small. Therefore, the method of the present invention has various advantages compared to repairing by filling with a single polyolefin sheet.
  • the method of the present invention is easy to deal with damage of various shapes.
  • the metal material is a curved pipe or a tower or tank
  • if damage occurs to a curved portion such as a bent portion or branch portion it is extremely difficult to apply primer or adhesive evenly to the sheet using a method of filling it with a single polyolefin sheet, but the method of the present invention makes it easy to repair such curved portions.
  • the filling section is formed by stacking multiple sheet layers.
  • the present invention has various advantages over forming a filling section with a single sheet layer.
  • anti-corrosion coating layers for metal materials come in a variety of thicknesses, and the method of the present invention, which uses multiple sheet layers, can accommodate anti-corrosion coating layers of various thicknesses.
  • the adhesive layer between the metal material and the polyolefin sheet is prone to deterioration due to the difference in thermal expansion coefficient between the metal material and the polyolefin sheet.
  • the thermal expansion coefficient between the sheet layers there is no difference in the thermal expansion coefficient between the sheet layers, so deterioration is unlikely to occur in the adhesive layer between the sheet layers.
  • the method of the present invention uses multiple sheet layers, each of which is constructed by joining multiple sheets together, making repairs extremely easy and enabling the repaired area to have excellent stability and durability.
  • FIG. 2 is a schematic cross-sectional view of a metal material.
  • 1 is a schematic cross-sectional view of a damaged portion of a corrosion-resistant coating layer of a metal material and its surrounding area.
  • 4 is a schematic cross-sectional view of the metal material after a coating removal portion forming step is performed.
  • FIG. 10 is a plan view of the metal material after the coating removal portion forming step is performed.
  • FIG. 10 is a plan view of the metal material after the coating removal portion forming step is performed.
  • FIG. 4 is a schematic cross-sectional view of the metal material after a filling portion forming process is performed.
  • FIG. 10 is a schematic cross-sectional view of the metal material after a cover portion forming step is performed.
  • FIG. 13 is a plan view of the metal material after the cover portion forming process is performed.
  • (a) State after the first sheet layer has been formed (a') State after the partially coated portion has been formed after the first sheet layer has been formed (b) State after the second sheet layer has been formed
  • Figure 14 State after the second sheet layer has been formed and a portion of the coating has been removed (c) State after the third sheet layer has been formed (d) State after the cover portion forming process has been carried out
  • the present invention relates to a method for repairing damage to a corrosion-resistant coating layer 2 of a metal material 1 coated with the corrosion-resistant coating layer 2 made of polyolefin.
  • Figure 1 shows a schematic cross-sectional view of the metal material 1 before repair in the present invention.
  • the metal material 1 is coated with a corrosion-resistant coating layer 2 made of polyolefin.
  • metal material there are no particular limitations on the type of metal that constitutes the metal material 1, and examples include iron, aluminum, copper, zinc, steel, etc.
  • metal material there are no particular limitations on the shape of the metal material 1, and examples include metal plates, metal pipes, metal rods, and metal containers such as tanks.
  • the metal pipe When the metal material 1 is a metal pipe, the metal pipe may have an anticorrosive coating layer 2 on its inner surface, may have an anticorrosive coating layer 2 on its outer surface, or may have metal layers on both its inner and outer surfaces.
  • the repair method of the present invention is applicable to the anticorrosive coating layer 2 on either the inner or outer surface.
  • the metal pipe when the metal material 1 is a metal pipe, the metal pipe may be a straight pipe, a curved pipe (a metal pipe having a bent portion), a branch pipe, a reducer, or the like.
  • the inner diameter of the metal pipe is, for example, 20 cm or more, 40 cm or more, or 50 cm or more, and 10 m or less, 5 m or less, or 3 m or less.
  • the metal material 1 is a steel pipe whose inner and/or outer surface is coated with the anticorrosive coating layer, particularly when the steel pipe is a steel pipe for transporting liquids (water, chemicals, etc.), there are many opportunities for damage to occur, and such steel pipes are widely used, so the advantage of the present invention, that a repaired portion with excellent stability and durability can be formed by a simple method, can be easily utilized.
  • the metal material 1 is a steel pipe
  • more specific examples include electric resistance welded steel pipe, forged steel pipe, galvanized steel pipe, seamless steel pipe, spiral steel pipe, UOE steel pipe, etc., but are not limited to these.
  • the corrosion-resistant coating layer 2 is made of polyolefin and serves to protect the metal material 1 from corrosion and impact.
  • the polyolefin that is the raw material of the corrosion-resistant coating layer 2 includes low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, polybutene, and copolymers thereof.
  • the anticorrosive coating layer 2 may be formed using one kind of these alone, or the anticorrosive coating layer 2 may be formed using two or more kinds of these in combination.
  • the thickness of the corrosion-resistant coating layer 2 (hereinafter, in this specification, "thickness” means the average thickness unless otherwise specified) is preferably 0.5 mm or more, more preferably 1 mm or more, particularly preferably 1.2 mm or more, and most preferably 1.5 mm or more. Also, it is preferably 5 mm or less, more preferably 4.5 mm or less, and particularly preferably 4 mm or less. When the thickness is equal to or greater than the lower limit, the anticorrosive property and the impact resistance are excellent, whereas when the thickness is equal to or less than the upper limit, it is advantageous in terms of cost.
  • a coating removal portion forming process is performed.
  • the damaged portion 21 of the corrosion protection coating layer 2 and the raised portion 22 around the damaged portion 21 are removed to form a coating removal portion 23 where the metal material 1 is exposed.
  • Figure 2 is a schematic cross-sectional view showing the vicinity of a damaged portion 21 in the corrosion-resistant coating layer 2 of the metal material 1.
  • the damaged portion 21 occurs in the corrosion-resistant coating layer 2 due to contact with other materials during storage or transportation, or contact with tools during maintenance. It can be visually confirmed that the area around the damaged portion 21 is raised above the surrounding surface of the corrosion-resistant coating layer 2 (raising portion 22) (note that the damaged portion 21 and the raised portion 22 are exaggerated in Figure 2).
  • the damaged portion 21 and the raised portion 22 around the damaged portion 21 are removed.
  • the raised portion 22 can be removed by a known method using a cutter, scissors, a power tool, or the like.
  • FIG. 3 shows a schematic cross-sectional view of the metal material 1 after the coating removal portion formation process
  • FIG. 4 shows a plan view.
  • the corrosion protection coating layer 2 has been removed, and the metal material 1 is exposed (representing the coating removal portion 23).
  • the corrosion-resistant coating layer 2 is removed from the damaged portion 21 and the raised portion 22 (i.e., the portion that can be visually confirmed to be raised above the surface of the surrounding corrosion-resistant coating layer 2), but a generous amount (more than enough) of the corrosion-resistant coating layer 2 may be removed, including the corrosion-resistant coating layer 2 on the outside of the raised portion 22.
  • the corrosion-resistant coating layer 2 may be removed including the corrosion-resistant coating layer 2 on the outside of the raised portion 22, thereby forming, for example, a rectangular coating removal portion 23 as shown in FIG. 5.
  • the area of the coating removal portion 23 is preferably 50 cm2 or more, more preferably 75 cm2 or more, and particularly preferably 100 cm2 or more. Also, the area is preferably 500 cm2 or less, more preferably 400 cm2 or less, and particularly preferably 300 cm2 or less.
  • the coating removal portion forming step is followed by the filling portion forming step.
  • the coating removal portion 23 is filled by stacking and adhering two or more sheet layers (31, 32, 33) of filling polyolefin sheets (31A, 32A, 33A) to form a filling portion 3 having approximately the same height as the corrosion protection coating layer 2 surrounding the coating removal portion 23.
  • FIG. 6 shows a schematic cross-sectional view of the metal material 1 after the filling portion formation process has been performed.
  • the polyolefin sheet is filled in the area that was previously the coating removal area 23 formed by removing the damaged area 21 and the raised area 22 around the damaged area 21.
  • filling polyolefin sheets (31A, 32A, 33A) are laminated as two or more sheet layers (31, 32, 33) in the coating removal section 23, and each sheet layer (31, 32, 33) has a seam line because it is formed by joining multiple filling polyolefin sheets (31A, 32A, 33A), and the seam lines (31B, 32B, 33B) of adjacent sheet layers are prevented from overlapping.
  • Figures 7, 8, and 9 show a specific example of the filling section formation process, using an example in which three sheet layers are laminated in the coating removal section 23.
  • a filler polyolefin sheet 31A is adhered onto the metal material 1 exposed in the coating removal portion 23 to form a first sheet layer 31 (FIGS. 7(a), 8(a), and 9(a)).
  • the first sheet layer 31 is constructed by joining together a plurality of filling polyolefin sheets 31A, and seam lines 31B are formed between the sheets 31A.
  • Sheet 31A is made by cutting a commercially available standard (e.g. rectangular) polyolefin sheet to fit the shape of coating removal section 23. If coating removal section 23 is formed in a rectangular shape, for example, as shown in FIG. 5, in the coating removal section formation process, first sheet layer 31 will also be rectangular, as shown in FIG. 9(a), reducing the effort required for cutting the sheet in the filling section formation process.
  • a commercially available standard e.g. rectangular
  • a filler polyolefin sheet 32A is adhered thereon to form a second sheet layer 32 (FIGS. 7(b), 8(b), and 9(b)).
  • the second sheet layer 32 is also constructed by joining a plurality of filling polyolefin sheets 32A, and a seam line 32B is formed between the sheets 32A.
  • the seam line 32B in the second sheet layer 32 is formed so as not to overlap with the seam line 31B in the first sheet layer 31 (the adjacent sheet layer) (note that in Figures 8(b) and 9(b) the seam line 31B in the first sheet layer 31 is shown by a dotted line).
  • seam lines 32B and 31B of adjacent sheet layers as far apart as possible.
  • a filler polyolefin sheet 33A is adhered thereon to form a third sheet layer 33 (FIGS. 7(c), 8(c), and 9(c)).
  • the third sheet layer 33 is also constructed by joining together a plurality of filling polyolefin sheets 33A, and a seam line 33B is formed between the sheets 33A.
  • the seam line 33B of the third sheet layer 33 is formed so as not to overlap with the seam line 32B of the second sheet layer 32 (the adjacent sheet layer) (note that the seam line 32B of the second sheet layer 32 is shown by a dashed line in Figures 8(c) and 9(c)).
  • seam line 33B and seam line 32B are positioned as far apart as possible.
  • the position of seam line 33B of the third sheet layer 33 may be approximately the same as the position of seam line 31B of the first sheet layer 31.
  • the corrosion-resistant coating layer 2 is made of polyolefin, and the filling portion 3 is formed by adhering a filling polyolefin sheet.
  • the thermal expansion coefficients of the filling portion 3 and the surrounding corrosion-resistant coating layer 2 are approximately the same, and even in an environment where the temperature around the metal material 1 may rise, the repaired portion of the metal material repaired by the method of the present invention is less likely to break.
  • polyolefin resin that is the raw material of the corrosion-resistant coating layer 2 are as described above.
  • the polyolefin that constitutes the corrosion-resistant coating layer 2 and the polyolefin that constitutes the filling polyolefin sheets (31A, 32A, 33A) are desirably chemically identical. That is, it is desirably to select a polyolefin sheet that is chemically identical to the polyolefin that constitutes the corrosion-resistant coating layer 2 of the metal material 1 to which the method of the present invention is applied, and use it as the filling polyolefin sheet (31A, 32A, 33A). By doing so, it becomes easier to prevent damage to the repaired portion in an environment where the temperature around the metal material 1 may rise.
  • the filling polyolefin sheet is laminated as two or more sheet layers.
  • the number of sheet layers is preferably 2, 3 or 4. If the sheet layers are 4 or more, the work time will increase and the number of bonding points will increase, which may reduce the stability and durability of the repaired area.
  • the thickness of the regular polyolefin sheet is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more, and is preferably 5 mm or less, more preferably 4 mm or less, and particularly preferably 3 mm or less.
  • the thickness is within the above range, the number of sheet layers can be easily set within the above desired range.
  • each of the regular polyolefin sheets is preferably 50 cm2 or more, more preferably 75 cm2 or more, and particularly preferably 100 cm2 or more. Also, the area is preferably 500 cm2 or less, more preferably 400 cm2 or less, and particularly preferably 300 cm2 or less. When the area is equal to or greater than the lower limit, the workability (work time) is likely to be improved, whereas when the area is equal to or less than the upper limit, the adhesive and primer can be evenly applied to the sheet, and peeling of the sheet is unlikely to occur.
  • the polyolefin sheet of a fixed shape is cut to fit the shape of the coating removal area 23 before use.
  • the coating removal area 23 has a random shape as shown in FIG. 4, the area of the sheet after cutting may fall below the lower limit, but this does not pose any particular problem.
  • the bonding in the filling section formation process is preferably performed by applying a primer to the filling polyolefin sheet, drying the primer, and then applying an adhesive to the filling polyolefin sheet.
  • the first sheet layer 31 is formed by adhering sheet 31A onto the metal material 1 exposed in the coating removal section 23. Applying a primer or adhesive to sheet 31A allows for more uniform application and improves adhesion, rather than applying the primer or adhesive to the metal material 1.
  • the second and subsequent sheet layers are formed by bonding polyolefin sheets together.
  • a primer or adhesive may be applied to the polyolefin sheet constituting the existing sheet layer, to the polyolefin sheet to be newly installed, or to both polyolefin sheets.
  • the adhesion between the adhesive and the adhesion surface can be improved.
  • the primer used in the filling portion forming step include an amine-based primer, a synthetic rubber-based primer, an acrylic-based primer, a urethane-based primer, and an epoxy-based primer. These primers may be used alone or in combination of two or more kinds. From the viewpoint of work efficiency, it is preferable to use one kind alone.
  • the coating amount of the primer used in the filling portion forming step is preferably 0.1 g/ m2 or more, more preferably 0.5 g/ m2 or more, and particularly preferably 1.0 g/ m2 or more. Also, it is preferably 6.0 g/ m2 or less, more preferably 3.0 g/ m2 or less, and particularly preferably 2.0 g/m2 or less.
  • the coating amount is equal to or more than the lower limit, the workability (work time) is likely to be improved, and it is also advantageous in terms of cost.
  • the area is equal to or less than the upper limit, the adhesiveness is likely to be improved.
  • the adhesive is applied on top of the primer.
  • the timing of applying the adhesive is such that the time interval between completing application of the primer and starting application of the adhesive is preferably 0.5 minutes or more, more preferably 1 minute or more, and particularly preferably 2 minutes or more. It is also preferably 10 minutes or less, more preferably 7 minutes or less, and particularly preferably 5 minutes or less.
  • adhesives used in the filling portion formation process include polyvinyl acetate adhesives, cyanoacrylate adhesives, cellulose adhesives, polyester adhesives, polyether adhesives, polyamide adhesives, polyimide adhesives, epoxy adhesives, urethane adhesives, rubber adhesives, silicone adhesives, etc. These adhesives may be used alone or in combination of two or more kinds. From the viewpoint of work efficiency, it is preferable to use one kind alone.
  • the amount of adhesive applied in the filling portion forming step is preferably 20 g/ m2 or more, more preferably 30 g/ m2 or more, and particularly preferably 40 g/ m2 or more. Also, it is preferably 70 g/ m2 or less, more preferably 60 g/ m2 or less, and particularly preferably 50 g/ m2 or less.
  • the coating amount is equal to or more than the lower limit, the workability (work time) is likely to be improved, and it is also advantageous in terms of cost.
  • the area is equal to or less than the upper limit, the adhesiveness is likely to be improved.
  • the filling portion forming step it is preferable to roughen the surface of the metal material 1 exposed in the coating removal portion 23 with sandpaper or the like in order to improve adhesion prior to placing the polyolefin sheet.
  • the filling portion forming step may be followed by the cover portion forming step.
  • a cover polyolefin sheet 41 is adhered to the boundary portion 34 between the filling portion 3 and the corrosion-resistant coating layer 2 surrounding the filling portion 3 to form a cover portion 4 that covers the boundary portion 34 from above ( Figures 10 and 12).
  • a cover polyolefin sheet 41 is attached by adhering it onto the boundary 34 between the filling portion 3 and the corrosion-resistant coating layer 2 .
  • the cover portion 4 may be formed by using a single cover polyolefin sheet 41 to cover the filling portion 3 (the uppermost sheet layer) and the boundary portion 34, or as shown in Figures 12 and 13, multiple cover polyolefin sheets may be used to cover only the portion necessary to cover the boundary portion 34, and not to cover a portion of the filling portion 3 (the uppermost sheet layer).
  • the shape of the cover polyolefin sheet 41 does not have to be rectangular as shown in Figs. 11 and 13, and may be of a random shape or the like.
  • the thickness of the cover polyolefin sheet 41 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and particularly preferably 0.5 mm or more. It is also preferably 5 mm or less, more preferably 4 mm or less, and particularly preferably 3 mm or less.
  • the area of the cover polyolefin sheet 41 is preferably 100 cm2 or more, more preferably 150 cm2 or more, and particularly preferably 200 cm2 or more. Also, it is preferably 1000 cm2 or less, more preferably 800 cm2 or less, and particularly preferably 600 cm2 or less.
  • each cover polyolefin sheet 41 is preferably 50 cm2 or more, more preferably 75 cm2 or more, and particularly preferably 100 cm2 or more. Also, it is preferably 500 cm2 or less, more preferably 400 cm2 or less, and particularly preferably 300 cm2 or less.
  • the adhesion during the cover formation process is also preferably performed by applying a primer to the cover polyolefin sheet 41, drying the primer, and then applying an adhesive to the cover polyolefin sheet 41.
  • a primer or adhesive may be applied to the filling polyolefin sheet (33A in the examples shown in Figures 7, 8, and 9(a)) which is the outermost layer of the filling portion 3, or to the cover polyolefin sheet 41, or to both polyolefin sheets.
  • a primer or adhesive may be applied to the filling polyolefin sheet (33A in the examples shown in Figures 7, 8, and 9(a)) which is the outermost layer of the filling portion 3, or to the cover polyolefin sheet 41, or to both polyolefin sheets.
  • primers and adhesives used for bonding in the cover portion formation process their preferred application amounts, and the time interval between completing application of the primer and starting application of the adhesive are the same as those described above for the filling portion formation process.
  • the polyolefin cover sheet 41 used in the cover formation process is preferably roughened on only one side, with the roughened side being the adhesive surface for the filling section 3 and the anticorrosive coating layer 2 (there is no point in roughening the non-adhesive surface of the polyolefin cover sheet 41).
  • a partially coated-removed portion 24 may be formed by removing the corrosion-resistant coating layer 2 around the underlying sheet layer so that the portion has approximately the same height as the "underlying sheet layer.”
  • An example of such a process is shown in FIGS.
  • first sheet layer 31 is the same as that shown in Figure 7(a) ( Figure 14(a)).
  • the anticorrosive coating layer 2 around the sheet layer 31 is removed to form a partially-removed portion 24 (FIG. 14(a')).
  • the anticorrosive coating layer 2 is removed so that the height of the anticorrosive coating layer 2 below the partially-removed portion 24 is approximately the same as the height of the first sheet layer 31.
  • the second sheet layer 32 is formed on the first sheet layer 31 (FIG. 14(b)).
  • a filling polyolefin sheet 32A is filled in so as to include the partially-covered portion 24.
  • the seam line 32B of the second sheet layer 32 and the seam line 31B of the first sheet layer 31 are arranged not to overlap each other.
  • the anticorrosive coating layer 2 around the periphery of the sheet layer 32 is similarly removed to form a partially-removed portion 24 (Fig. 15(b')), and then the third sheet layer 33 is formed by filling the partially-removed portion 24 with a filling polyolefin sheet 33A (Fig. 15(c)).
  • the cover portion forming process may be performed ( Figure 15 (d)).
  • the filling portion 3 has a cone-like shape as shown in Figures 15(c) and 15(d). By doing this, the boundary 34 between the filling portion 3 and the corrosion-resistant coating layer 2 surrounding the filling portion 3 is no longer in a straight line, so that the intrusion of liquid from the boundary 34 can be more effectively prevented.
  • the repair method of the present invention can easily repair damage to the corrosion-resistant coating layer of metal materials, and can provide a repair method that provides excellent stability and durability in the repaired portion. Therefore, metal materials repaired by the repair method of the present invention can be widely used to repair steel pipes that make up water pipes for transporting water supply and sewerage, agricultural water, industrial water, etc.; piping for chemicals and cooling water in factories and plants; pipelines for transporting gas, electricity, oil, etc.

Landscapes

  • Laminated Bodies (AREA)
  • Protection Of Pipes Against Damage, Friction, And Corrosion (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
PCT/JP2022/042788 2022-11-18 2022-11-18 金属材における防食被覆層の損傷の補修方法 Ceased WO2024105867A1 (ja)

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CN202280101232.9A CN120076927A (zh) 2022-11-18 2022-11-18 金属材料中的防腐蚀被覆层的损伤的修补方法
PCT/JP2022/042788 WO2024105867A1 (ja) 2022-11-18 2022-11-18 金属材における防食被覆層の損傷の補修方法
JP2023514873A JP7268262B1 (ja) 2022-11-18 2022-11-18 金属材における防食被覆層の損傷の補修方法

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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51120429A (en) * 1975-04-16 1976-10-21 Sumitomo Metal Ind Ltd Method for repairing joints of coated steel pipe
JPS5520957A (en) * 1978-08-02 1980-02-14 Kooya Kk Corrosion preventing method for transport pipe
JPH05245935A (ja) * 1992-03-03 1993-09-24 Sumitomo Metal Ind Ltd 意匠性防食被覆鋼材の補修方法
JP2006194368A (ja) * 2005-01-14 2006-07-27 Nippon Steel Corp 現地溶接部の防食被覆構造
JP2007205012A (ja) * 2006-02-01 2007-08-16 Nippon Steel Corp 鉄鋼構造物の防食被覆の補修方法及び水中用補修シート
WO2011114001A1 (en) * 2010-03-18 2011-09-22 Borealis Ag Method of repairing a pipe coating
US20140048164A1 (en) * 2011-08-16 2014-02-20 James M. Souza Pipe Restraining Repair Method and Structure for Piping Structures Using Composites
US20180038542A1 (en) * 2015-02-17 2018-02-08 J Van Beugen Beheer B.V. Metal pipes with anticorrosive polyolefin covering layer
US20190049057A1 (en) * 2017-08-09 2019-02-14 Milliken Infrastructure Solutions, Llc Strengthened polyethylene tubular member
DE102018129495A1 (de) * 2018-11-22 2020-05-28 Brandenburgische Technische Universität Cottbus-Senftenberg Verfahren zur Reparatur eines Metall-Faser-Kunststoff-Verbund-Bauteils

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51120429A (en) * 1975-04-16 1976-10-21 Sumitomo Metal Ind Ltd Method for repairing joints of coated steel pipe
JPS5520957A (en) * 1978-08-02 1980-02-14 Kooya Kk Corrosion preventing method for transport pipe
JPH05245935A (ja) * 1992-03-03 1993-09-24 Sumitomo Metal Ind Ltd 意匠性防食被覆鋼材の補修方法
JP2006194368A (ja) * 2005-01-14 2006-07-27 Nippon Steel Corp 現地溶接部の防食被覆構造
JP2007205012A (ja) * 2006-02-01 2007-08-16 Nippon Steel Corp 鉄鋼構造物の防食被覆の補修方法及び水中用補修シート
WO2011114001A1 (en) * 2010-03-18 2011-09-22 Borealis Ag Method of repairing a pipe coating
US20140048164A1 (en) * 2011-08-16 2014-02-20 James M. Souza Pipe Restraining Repair Method and Structure for Piping Structures Using Composites
US20180038542A1 (en) * 2015-02-17 2018-02-08 J Van Beugen Beheer B.V. Metal pipes with anticorrosive polyolefin covering layer
US20190049057A1 (en) * 2017-08-09 2019-02-14 Milliken Infrastructure Solutions, Llc Strengthened polyethylene tubular member
DE102018129495A1 (de) * 2018-11-22 2020-05-28 Brandenburgische Technische Universität Cottbus-Senftenberg Verfahren zur Reparatur eines Metall-Faser-Kunststoff-Verbund-Bauteils

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JP7268262B1 (ja) 2023-05-02
CN120076927A (zh) 2025-05-30

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