JPH01275032A - Method of repairing damaged part of polyolefin covered steel - Google Patents

Abstract

PURPOSE:To make it unnecessary for the waiting time during the repairing process and the heating in adhesion, and make it to be adhered firmly by applying the primer containing an organic metal compound to a polyolefin covered layer and applying an alpha-cyanoacrylate resin composite to the applied surface thereof. CONSTITUTION:Prepared is a repairing polyolefin sheet 4a in the form of being inserted into a damaged part 3a. The primer containing an organic metal compound is applied to the steel surface 5 exposed on a damaged part 3a and the side surface of a millcoat polyolefin covered layer in the vicinity of the damaged part 3a, and a primer is applied to the one and side surface of the repairing polyolefin sheet 4a. After the primer is air dried, an alpha-cyanoacrylate resin composite is applied to both or one primer applied surface of the primer applied surface of the steel surface 5 and the millcoat polyolefin covered layer 2, and the primer applied surface of the repairing polyolefin sheet 4a, thereby making the millcoat polyolefin covered layer 2 and the repairing polyolefin sheet 4a to be adhered each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for repairing damaged parts of polyolefin-coated steel materials such as polyethylene-coated steel sheet piles and polyethylene-coated steel pipes.

[Prior art] Polyolefin-coated steel materials were developed for the purpose of maintaining the corrosion resistance properties of anti-corrosion steel pipe piles, anti-corrosion steel sheet piles, etc. used as civil engineering construction materials such as marine structures and seawall construction over a long period of time. . Polyolefins, particularly polyethylene, have become the mainstream of anticorrosion coatings in recent years because they have excellent mechanical properties such as hardness and impact strength, weather resistance, water resistance, chemical resistance, and the like. Polyolefin coated FiWi material is
It is manufactured by an extrusion lining method, sheet lining method, powder lining method, etc., and a mill coat polyolefin coating layer is formed on the steel surface.

This polyolefin-coated steel material may be damaged by impacts caused by contact between steel materials or jigs and tools during storage, transportation, laying, and pouring. If such damage is left untreated, it may cause rusting or peeling of the coating layer.
Since the excellent anti-corrosion effect cannot be maintained, it is necessary to repair it.

Several methods are known as conventional repair techniques for the damaged portions of the mill coat polyolefin coating layer as described above. FIG. 3 is an explanatory diagram of the repair method shown in Japanese Patent Application Laid-Open No. 61-197077. In FIG. 3, 1 is a steel material and 2 is a mill-coated polyolefin coating layer. The repair method is to apply a urethane-based primer 10 to the damaged area of the coating layer 2 and its surroundings, and then apply a two-part curable primer to the damaged area. Repair is carried out by filling a polyurethane sealant 11 and heat-pressing a polyolefin sheet 12 coated with the same primer as the primer 10 thereon.

FIG. 4 is an explanatory diagram of the repair method shown in Japanese Patent Application Laid-Open No. 61-170586. In FIG. 4, 1 is a steel material and 2 is a mill-coated polyolefin coating layer.The repair method is to fill the damaged part with sealant 13, and then apply the mill-coated polyolefin coating layer 2 on the upper surface of the sealant 13 and around it. A cross-linked polyolefin sheet 15 having an adhesive layer 14 with a softening point of 50° C. or lower is heat-pressed, and a polyolefin sheet 16 with a softening point of 90° C. or higher is continuously coated with the cross-linked polyolefin sheet 15 and the mill coat polyolefin coating layer 2. Heat and press as shown.

[Problem to be solved by the invention] However, the above-mentioned conventional technology has the following problems.

In the method of JP-A-61-197077 shown in FIG.
(1) In preparing a thermosetting resin sealant, there is a complication in that two liquids must be mixed. (21 You cannot move on to the next process until the sealant has finished curing. (
3) When press-bonding a polyolefin sheet to a mill-coated polyolefin coating layer, there are problems in construction, such as the need for heating.

In addition, the method of JP-A-61-170586 shown in Fig. 4 has the same problems as JP-A-617197077 due to (1) the use of a two-component mixture sealant, and (2) cross-linking of polyolefin sheets. Heat is required to heat and press the polyolefin sheet and the mill-coated polyolefin coating layer, and (3) since the polyolefin sheet has a high softening point, it may cause performance deterioration or thermal deformation of the cross-linked polyolefin sheet and the mill-coated polyolefin coating layer. There are problems such as difficulty in firmly adhering the material without causing any damage.

As described above, in the conventional technology, it is necessary to heat the surface of the steel material and the coating layer, it requires waiting time for curing, and it is also difficult to maintain close contact between the reinforcing polyolefin sheet and the mill coat polyolefin coating layer of the steel material. There was a problem that it was insufficient.

The present invention solves the problems of the prior art as described above, does not require waiting time during the repair process, does not require heating when adhering the repair polyolefin sheet to the mill coat polyolefin coating layer of the steel material, Another object of the present invention is to provide a method for repairing a damaged part of a polyolefin-coated steel material that can be firmly adhered.

[Means for solving Section H, P]

In order to achieve the above object, the method for repairing a damaged part of a polyolefin-coated steel material of the present invention includes applying a primer containing an organometallic compound to the damaged part of the polyolefin-coated steel material and the mill coat polyolefin coating layer around the damaged part,
A primer is applied to one side of a repair polyolefin sheet shaped to be inserted into the damaged area, and then at least one of the primer-coated surface of the mill-coated polyolefin coating layer in and around the damaged area and the primer-coated surface of the repair polyolefin sheet. 6. Applying an α-cyanoacrylate resin composition to the primer-coated surface, and adhering the repair polyolefin sheet to the damaged area with the primer-coated surfaces facing each other.6 Also, repair of polyolefin steel materials repaired by the above method A process for smoothing the surface of the mill-coated polyolefin coating layer in and around the repaired area, and applying the primer to the mill-coated polyolefin coating layer in and around the repaired area, and applying the primer to a size that covers the repaired area and its surroundings. The primer is applied to one side of the polyolefin sheet, and then α-cyanoacrylate is applied to at least one of the primer-coated surface of the mill-coated polyolefin coating layer in and around the repair area and the primer-coated surface of the repair polyolefin sheet. A resin composition is applied, and the repair polyolefin sheet is adhered to the repair portion and the mill coat polyolefin coating layer around the repair portion with the primer coated surfaces facing each other to form a protective layer.

The organometallic compound contained in the primer is a compound selected from metal alcoholates and metal acetylacetone complex salts.

The treatment method for smoothing the surface of the repaired area and the mill-coat polyolefin coating layer in the vicinity thereof in the above method involves heating the repair polyolefin sheet to a temperature higher than the melting point of the surface material of the mill-coat polyolefin coating layer in the vicinity thereof. Press with a heated heater.

The polyolefin referred to in the present invention refers to various types of polyethylene from low density to high density, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polybutene-1, poly-4-methyl-1-pentene, or polymer blends or modifications thereof. A general term for compositions whose main component is the body.

The repair polyolefin sheet is made by extrusion molding, press molding, or injection molding the various polyolefins described above into a sheet shape. The type of polyolefin sheet for repair is preferably the same type as the mill coat polyolefin coating layer of the steel material. This is to prevent differences in surface properties and mechanical properties between the repaired area and the surrounding mill coat polyolefin coating layer.

A primer is a product in which a specific organometallic compound is dissolved in a specific organic solvent. The organometallic compound is selected from metal alcoholates and metal acetylacetone complex salts, such as aluminum trisacetylacetate, aluminum ethyl acetoacetate diisopropylate, aluminum trisisopropylate, tetraline propyl titanate, tetrabutyl titanate, acetylacetone cobalt, Acetylacetone manganese.

Dibutyltin diacetate and the like are used. Further, as the organic solvent, those having a critical surface tension lower than that of the mill coat polyolefin coating layer of the steel material and the polyolefin sheet for repair, such as acetone, trichloroethane, ethanol, ethyl acetate, tetrahydrofuran, toluene, etc., are used.

The α-cyanoacrylate resin composition is CH=C
(CN)COOCH, CH=C(CN)COOC2H5 and other α-cyanoacrylate monomers are used as a base, and a polymethyl methacrylate resin, a thickener such as acrylic rubber, a stabilizer, and a pigment are mixed therein, and further, In order to achieve a curing speed suitable for the construction conditions, it was prepared by mixing polymerization accelerators such as basic metal hydroxides, basic inorganic salts, and various amine compounds, or polymerization inhibitors such as aromatic sulfonic acid and SO2. It is something.

[Function] The primer is applied to make the surface of the polyolefin resin hydrophilic.
It is an essential means for adhering the mill coat polyolefin coating layer and the repair polyolefin sheet together with the application of the cyanoacrylate resin composition.

The α-cyanoacrylate resin composition is a composition that exhibits strong adhesion to hydrophilic surfaces and adheres at room temperature. For this reason, if a primer is applied to change the hydrophobic polyolefin surface to hydrophilic, and an α-cyanoacrylate resin composition is applied to the hydrophilic surface coated with this primer for adhesion, α- Due to the adhesive action of the cyanoacrylate resin composition, the mill coat polyolefin coating layer and the polyolefin sheet for auxiliary IC can be strongly adhered to each other without heating.

The present inventors have found that the above-mentioned metal alcoholates, metal-acetylacetone complex salts, etc. exhibit excellent effects as substances that impart such hydrophilicity, and have selected the above-mentioned organometallic compounds. This method was applied to the repair of polyolefin-coated steel.

In addition, as a solvent for dissolving the organometallic compound, a solvent whose critical surface tension is smaller than that of the mill-coat polyolefin coating layer and the repair polyolefin sheet is used, but if a solvent with a critical surface tension larger than the respective polyolefins mentioned above is used, the primer will not repair. The entire surface cannot be wetted, and the adhesive effect of the above-mentioned α-cyanoacrylate resin composition cannot be fully exhibited.

The primer is applied by a spray method, a dipping method, a brushing method, or the like.

The adhesion method for repair is to apply pressure using a roller or the like after applying an α-cyanoacrylate resin composition to at least one of the mill-coat polyolefin coating layer coated with a primer and the repair polyolefin sheet. Adhesiveness develops within a short period of several seconds to several minutes, and there is no need for particular heating during that time. The α-cyanoacrylate resin composition is applied using a spatula or the like.

In addition, when a protective layer is formed by adhering a polyolefin sheet for repair over the repaired area that has been repaired by adhering a polyolefin sheet for repair to the damaged area, the surface of the mill-coated polyolefin coating layer in and around the repaired area It is even more effective if it is smoothed. This is because by eliminating the level difference between the repair polyolefin sheet and the mill coat polyolefin coating layer in the repair portion, formation of an air layer is avoided and sufficient adhesion is achieved.

The process of smoothing and eliminating the difference in level between the repair polyolefin sheet and the mill-coat polyolefin coating layer in the repair area is performed, for example, by heating and pressing the two polyolefins at the same time, and the heating temperature at this time is set to a temperature that is equal to the temperature of the object of heating and pressing. It is preferable to set the temperature at a temperature 30 to 100°C higher than the melting point of the polyolefin. In this temperature range,
The construction is smooth and does not cause thermal deterioration of the resin.

In addition, the above-mentioned heating and pressing is performed by heating with a heater, and the material of the heater must be one that does not fuse with the polyolefin resin due to heating and pressing, such as chromium-plated steel or fluororesin-coated steel. be done.

EXAMPLES OF THE INVENTION Examples of the present invention will be described below. FIG. 1 is an explanatory diagram of an embodiment of the repair method of the present invention, in which (a) shows the repair method when damage reaching the shoulder surface occurs in the mill coat polyolefin coating layer, and (b) shows the repair method when damage reaches the shoulder surface. is a diagram showing a repair method when only the mill coat polyolefin coating is damaged. Figure 1(a).

In fbl, 1 is a steel material such as a steel sheet pile or a steel pipe, 2 is a mill coat polyolefin coating layer, and 3a and 3b are damaged parts. The repair method shown in the fat diagram is to first remove foreign objects and protrusions in the damaged area 3a and around it, smooth it, and then cut the repair polyolefin sheet 4 into a shape to be inserted into the damaged area 3a.
Prepare a. Next, a primer is applied to the exposed steel surface 5 and the side surfaces of the mill-coat polyolefin coating layer 2 around the damaged portion 3aG', and the primer is applied to one side and side surfaces of the repair polyolefin sheet 4a. After the primer is air-dried, an α-cyanoacrylate resin composition is applied to either or both of the steel surface 5 and the primer-coated surface of the mill coat polyolefin coating layer 2 and the primer-coated surface of the repair polyolefin seam 4a. Then, the mill coat polyolefin coating layer 2 and the repair polyolefin sheet 4a are bonded together. The repair method for the fbl diagram is to prepare a repair polyolefin sheet 4b that is thinner than that for the fa1 diagram, and repair the repair 1ω polyolefin sheet 4 using the same procedure as for the Fa1 diagram.
b to the damaged part 3b.

FIG. 2 is a diagram showing a repair method according to another embodiment,
This method creates a protective layer over the repaired area to make the repaired structure stronger. In FIG. 2, this method involves repairing the damaged area by the method shown in FIG. After melting, stop heating the heater and cool while pressing. By this operation, the difference in level between the mill coat polyolefin coating layer 2 and the repair layer of the repair polyolefin sheet 4 is eliminated and the layer becomes smooth. Then, a primer is applied to the bonded repair polyolefin sheet 4 and the mill coat polyolefin coating layer °2 around it, and the bonded repair polyolefin sheet 1-4 is then coated with a primer.
After applying a primer to one side of the repair polyolefin sheet 6, which covers and is cut into a smaller size than the primer-coated surface and serves as a protective layer, the primer-coated surfaces are made to face each other and adhered with an α-cyanoacrylate resin composition.

<Example 1> U-shaped side sheet pile with a high-density polyethylene coating of approximately 2IIll thickness on the convex side surface (Nippon Kokan Co., Ltd., NKSP-ma)
Two damaged areas reaching the steel surface with a diameter of 50 mm were artificially created. The polyethylene and exposed steel surfaces around this damaged area were wiped with thinner to remove any foreign material. Then, a primer containing 0.1% by weight of aluminum trisisopropylate in toluene (hereinafter referred to as Primer A) was used. and cobalt acetylacetone 0 in toluene
．． Primer containing 1% by weight (hereinafter referred to as Primer B)
Primer A or Primer B was applied to the two damaged areas with a brush.

Next, as a repair polyolefin sheet, two repair polyolefin sheets of 50 mm diameter were prepared by cutting a laminated sheet (2 city thick) of modified polyethylene and high-density polyethylene that had been given adhesive properties. The primer A or primer B was applied to the surface of the modified polyethylene layer, respectively. After the toluene in the primer was removed by air drying, an ethyl cyanoacrylate composition was applied with a spatula to the damaged area coated with the primer and the polyolefin sheet for repair, and immediately adhered by roll pressing.

The thus repaired polyethylene-coated steel sheet piles were subjected to a soil driving test and a collision test (the polyethylene-coated steel sheet piles were dropped from a height of 2 m and collided with the repaired portion). As a result, primer A, primer B
In repairs using any primer, peeling,
Abnormalities such as damage did not occur at all.

In addition, steel sheet piles repaired in the same manner as above and 200 mm
The repaired area was cut into pieces of 200 x 1m and subjected to a salt water spray test for 2000 hours, but no peeling occurred at all, and only a slight amount of rust occurred at the boundary between the repaired area and the mill-coated polyethylene coating layer. Met.

(Comparative Example) A repair experiment was conducted using the same polyethylene-coated steel sheet pile as in Example 1 without applying a primer. The repair method was the same as in Example 1 except that no limer was applied, and the same pouring test and collision test as in Example 1 were conducted, and the adhesive strength was almost lost due to pouring or collision. It was in a state where it could be easily peeled off by hand.

(Example 2) Using the same polyethylene-coated steel sheet pile as in Example 1, the two artificially created damaged parts were repaired by the repair method of Example 1, and then the repaired parts of the steel sheet pile were repaired. A heater made of the same curved surface and plated with hard chrome was applied to the two repaired areas and their surrounding areas, heated to about 200°C and pressed. Heating was stopped while the heater was heated and pressed, and after cooling to room temperature, the heater was removed. Then, Primer A or Primer B was applied to the two heated and pressed repaired areas and their surrounding areas, and Primer A and Primer B were applied to one side of two 1-thick high-density polyethylene sheets cut to 100 mm diameter. Coated. After air-drying, an ethyl cyanoacrylate composition was applied to each adhesive surface and bonded.

The same test as in Example 1 was conducted on the polyethylene-coated steel sheet piles repaired by this repair method. The result is
Regardless of whether Primer A or Primer B was used, no defects such as peeling, damage, or rust occurred in the repaired area in all tests.

[Effects of the Invention] The method for repairing damaged parts of polyolefin-coated steel according to the present invention is to apply an organic metal-containing primer that imparts hydrophilicity to the surface of polyolefin, and then apply a polyolefin sheet for repair using an α-cyanoacrylate resin composition. Since it is bonded, adhesiveness develops in a few seconds to several minutes, and strong adhesion can be achieved without the need for waiting time for curing or heating.

If a polyolefin sheet for repair is adhered by the same method to form a protective layer on the repaired portion repaired by the above-described method, the repair structure can be made stronger. When forming the protective layer, if the surface of the repair polyolefin sheet in the repair area and the surrounding mill coat polyolefin coating layer is smoothed, an air layer will not be formed between the repair area and the protective layer. A sufficient adhesive effect can be obtained.

Then, if a heat pressing method using a heater is adopted as a process for making the layer thickness of the repair polyolefin sheet of the repair portion and the surrounding mill coat polyolefin coating layer the same, the layer thicknesses can be easily made the same. At the same time, the adhesion between the repair polyolefin sheet and the surrounding mill coat polyolefin coating layer can be further strengthened.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of one embodiment of the repair method of the present invention (Figure b1 is a diagram showing a repair method when only the polyolefin coating is damaged, and Figure 2 is a diagram showing a repair method according to another embodiment. This is an explanatory diagram of a method of providing a protective layer on the repair layer to make the repair A6 structure stronger, and FIGS. 3 and 4 are explanatory diagrams of a repair method according to the prior art. 1. - Steel material, 2... Mill coat polyolefin coating layer, 3a, 3b-... Damaged part, 4.4a, 4b. 6... Polyolefin sheet for repair, 5... Steel material surface.

Claims (4)

[Claims] (1) Apply a primer containing an organic metal compound to the damaged part of the polyolefin-coated steel material and the mill-coated polyolefin coating layer around it, and apply the primer to one side and side of a polyolefin sheet for repair shaped to be inserted into the damaged part. and then applying an α-cyanoacrylate resin composition to the primer-coated surface of at least one of the primer-coated surface of the mill-coated polyolefin coating layer in and around the damaged area and the primer-coated surface of the repair polyolefin sheet, A method for repairing a damaged part of a polyolefin-coated steel material, comprising adhering the repair polyolefin sheet to the damaged part with the primer coated surfaces facing each other. (2) A treatment is performed to make the layer thickness of the repaired portion of the polyolefin steel material repaired by the method according to claim 1 and the mill-coat polyolefin coating layer around the repaired portion the same, and the mill-coat polyolefin coating layer around the repaired portion and the surrounding area is made the same. The primer is applied to one side of a repair polyolefin sheet large enough to cover the repaired area and its surroundings, and then the primer-coated surface of the mill coat polyolefin coating layer in and around the repaired area and the repaired area are coated with the primer. Apply an α-cyanoacrylate resin composition to at least one of the primer-coated surfaces of a polyolefin sheet for use, and apply the repair to the repaired area and the mill-coated polyolefin coating layer around the repaired area with the primer-coated surfaces facing each other. A method for repairing a damaged part of a polyolefin-coated steel material, the method comprising: adhering a polyolefin sheet for use to form a protective layer. (3) The method for repairing a damaged part of a polyolefin-coated steel material according to claim 1 or claim 2, wherein the organic metal compound contained in the primer is a compound selected from metal alcoholates and metal acetylacetone complex salts. . (4) The treatment method for making the layer thickness of the repair portion and the surrounding mill-coat polyolefin coating layer the same in claim 2 is carried out at a temperature higher than the melting point of the surface layer material of the repair polyolefin sheet and the surrounding mill-coat polyolefin coating layer. A method for repairing a damaged part of a polyolefin-coated steel material, the method comprising pressing with a heater heated to .