JPS6322979B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] This invention provides an anti-corrosion coating layer consisting of a heat-adhesive adhesive layer and an extrusion-molded plastic layer. This relates to anti-corrosion coated steel sheet piles that are thermally bonded to sheet piles, and is used for civil engineering and construction purposes, such as protective shelves that are installed underground in rivers, ports, coasts, etc. and exhibit excellent anti-corrosion performance. It is something that can be configured.

[Description of prior art]

Conventionally, steel sheet piles for civil engineering and construction have been used for the purpose of revetment of rivers, coasts, ports, etc., or for construction and dredging by driving a large number of steel sheet piles into the ground continuously to form a protective shelf. It has been used to secure the ground at work sites and prevent mud and sand from flowing into the work site and from collapsing.

These steel sheet piles are exposed to water such as river water, wastewater, rainwater, and seawater, the atmosphere, and sunlight in the outdoor natural environment, and are also in direct and strong contact with earth, sand, mud, and debris, so they are subject to significant corrosion. The above-mentioned corrosion is likely to occur, especially in environmental sites where running water, waves, etc., the atmosphere, and sunlight interact alternately, such as ports and estuaries, where the above-mentioned corrosion occurs violently. No preventive measures had been taken.
Therefore, even if conventional steel sheet piles are made of highly corrosion-resistant steel materials, they are susceptible to corrosion in the aforementioned natural environment, and their durability is relatively short and they cannot be used for long periods of time. In many cases, it could not be used for a period of time (for example, about 20 years or more).

Conventionally, to prevent corrosion of steel sheet piles, coating with inorganic zinc paint, tar/epoxy resin paint, epoxy resin or unsaturated polyester resin has been used.
Although FRP coatings were sometimes used, these were not effective corrosion protection methods in terms of mechanical strength, long-term durability, and economic efficiency.

[Requirements and effects of the present invention]

As a result of extensive research into an economical anti-corrosion coated steel sheet pile with high corrosion protection and high durability, the inventors found that an extruded uncrosslinked plastic layer is bonded to the steel sheet through a heat-adhesive adhesive layer. The present invention was completed based on the discovery that anti-corrosion coated steel sheet piles, which are closely adhered and adhered to the surface of the sheet piles, are excellent in corrosion resistance and durability.

That is, the present invention provides a method of extrusion-molding a steel sheet pile used for civil engineering, construction, etc. on at least a portion of one side with a heat-adhesive adhesive layer having an adhesion temperature within the range of about 50 to 200°C. The uncrosslinked plastic layers are thermally bonded together in close contact.
The present invention relates to an anti-corrosion coated steel sheet pile on which an anti-corrosion coating layer is formed.

The method for producing the anti-corrosion coated steel sheet pile of the present invention is a combination of relatively simple operations, and is highly productive and economical.

Further, the anti-corrosion coated steel sheet pile of the present invention has excellent anti-corrosion properties and durability due to the anti-corrosion coating layer consisting of the plastic layer and the adhesive layer.

[Explanation of each requirement of the present invention]

The present invention will be described in more detail below with reference to the accompanying drawings.

1 and 5 are perspective views showing an example of an installed state of a protective shelf in which the steel sheet piles according to the present invention are successively driven into the ground and are arranged in a connected manner. , and a cross-sectional view showing an enlarged partial cross section of the protective shelf.

FIG. 2 is a perspective view showing an example of a steel sheet pile used in the method of the present invention.

FIG. 3 and FIG. 4 are sectional views each showing an example of an anti-corrosion coated steel sheet pile of the present invention.

The steel sheet pile used in this invention is generally used for civil engineering and construction purposes, and is formed so that grooves with a small inner diameter are formed along both sides of the main body of the steel sheet pile. As long as it has a joint part that is bent at the front end, the main body may have not only a planar shape but also a curved surface such as a concave or convex surface. The shape and size are not particularly limited.

As shown in Figure 2, a typical steel sheet pile has a main body with a roughly square cross-sectional structure, and the rising parts (sometimes called flanges) 3 on both sides have a small inner diameter. It is a long steel plate structural member having a joint portion 4 which is bent outward to form a cylindrical shape. As shown in Fig. 1, the steel sheet piles 2 are made by driving the individual steel sheet piles into the ground one after another, connecting them at the joints 4 of the rising parts 3 on both sides of a large number of steel sheet piles, and connecting the steel sheet piles. This forms a protective shelf 1 that is lined up. In such construction, as shown in FIG. 5, it is sufficient that one side of the protective shelf, which is exposed to seawater, river water, etc., is coated with an anticorrosive coating.

Note that the cross-sectional shape of the steel sheet pile does not necessarily have to be as shown in FIG. 2; for example, the main body may be almost linear, Z-shaped, S-shaped, etc.

The steel sheet pile, which has a main body with a roughly 〓-shaped cross-sectional structure, is made of steel plates with a thickness within the range of approximately 5 to 30 mm, and a width of approximately 200 to 800 mm, with raised edges on both sides. It is sufficient that the height of the section is approximately 50 to 300 mm and the length is approximately 2 to 30 m. Other types of steel sheet piles may also have main sizes similar to the above-mentioned sizes. That's fine.

The anticorrosion coating layer 5 formed on the surface of the anticorrosion coated steel sheet pile of this invention has an adhesion temperature of about 50 to 200°C,
It may be a layer consisting of an adhesive layer 7 which is heat-adhesive, preferably at a temperature within the range of 80 to 180 DEG C., and an extruded uncrosslinked plastic layer 6.

The adhesive forming the adhesive layer may have an adhesive temperature within the above-mentioned range and can be thermally bonded to the plastic layer and the surface of the steel sheet pile with an appropriate adhesive force. Any type of adhesive may be used, such as a heat-fusible adhesive (such as a hot melt type adhesive) or a heat-curable adhesive, which has a suitable elasticity or Adhesives that retain flexibility and do not become too hard or brittle are suitable.

The above-mentioned adhesive may be a heat-fusible adhesive (hot-melt type adhesive) containing an olefin polymer or copolymer as a main component, or a heat-fusible adhesive containing the above-mentioned polymer and a tackifier as a main component. adhesive strength (180 degree peeling, tensile speed 10 mm/min, 20°C) to the surface of the steel sheets that make up the steel sheet pile.
Adhesives having a pressure of about 2 Kg/cm or more, particularly about 4 to 20 Kg/cm are suitable.

In this invention, examples of preferred adhesives include olefinic polymers or copolymers, (block) copolymers of aromatic hydrocarbons having vinyl groups and conjugated diene compounds, and tackifiers. Examples include adhesive compositions that are selectively blended to provide a hot melt type adhesive with an adhesion temperature of about 50 to 200°C.

Examples of olefin polymers or copolymers used in such adhesives include polyethylene, polypropylene, polyvinyl chloride, and modified polymers thereof (e.g., maleated polyethylene, maleated polypropylene, etc.), ethylene, Vinyl acetate copolymer, ethylene/lower alkyl (methyl, ethyl, propyl, butyl, etc.),
Examples include acrylate or methacrylate copolymers, ethylene/acrylic acid or methacrylic acid copolymers, and these can be used alone or as a mixture of two or more types.

Examples of (block) copolymers of aromatic hydrocarbons having vinyl groups and conjugated diene compounds include:
Examples include styrene/butadiene/styrene (block) copolymer and styrene/isoprene/styrene (block) copolymer.

The tackifier can be arbitrarily selected from tackifiers commonly used in known adhesive compositions. Examples of such tackifiers include rosin and rosin derivatives, such as glycerin esters of hydrogenated rosin; pinene resins, such as oligomers of β-pinene, pinene resins obtained from β-pinene and phenolic compounds; Hydrogen resins, such as aliphatic hydrocarbon resins (C5 fraction, pentene, isoprene,
1,3 pentadiene (single or copolymer),
Aromatic hydrocarbon resins (single or copolymers of C9 fraction, styrenes, indenes, etc.), alicyclic carbonized resins, coumaron resins, coumaron-indene resins, etc.; and phenolic resins, alkylphenolic resins, naphthenic resins Examples include oils, other polymeric substances such as modified terpenes, or oily substances.

In this invention, the adhesive layer of the coating layer includes, in addition to the above-mentioned components, inorganic fillers such as talc, carbonaceous, silica, alumina, mica, and carbon black, or antioxidants, and organic or inorganic fillers. Additives such as corrosion inhibitors, colorants, and softeners may also be added.

Examples of the corrosion inhibitor include inorganic corrosion inhibitors represented by metal chromates, metal phosphates, metal phosphites, metal borates, molybdates, metal nitrites, and the like; , metal salts of aromatic carboxylic acids, aliphatic or aromatic compounds having a plurality of hydroxyl groups, and organic corrosion inhibitors represented by organic acids such as tannic acid.

In this invention, the extruded uncrosslinked plastic layer of the anti-corrosion coating layer includes polyethylene,
It may be formed using thermoplastic resins such as polypropylene, copolymers of ethylene and propylene, olefin polymers such as ethylene/vinyl acetate copolymers, polyvinyl chloride, polyesters, and polyamides, or mixtures thereof. , or a mixture of these polymers and other thermoplastic resins.

The thermoplastic resin forming the plastic layer has a melt viscosity (measured using a high shear viscometer at a temperature of 230°C and a shear rate of
The measured value at 1 sec ^-1 ) is 10 ⁴ to 10 ⁸ poise, and the melt tension (melt tension meter; inflow angle 60
Measurement temperature: 230℃, extrusion speed: 10mm/
Plastic resins having a weight (measured in minutes) of 0.5 to 15 g, especially 1.0 to 10 g are suitable.

Further, the thermoplastic resin may contain known plasticizers, antioxidants, flame retardants, various colorants, fillers (charcoal, silica, carbon black, etc.), and the like.

The plastic layer has a tensile strength of 50~50 after being coated on the surface of the steel sheet pile via an adhesive layer.
It is preferable to configure the outermost layer (protective layer) of the anti-corrosion coating layer, which is 300Kg/cm ² and has an impact resistance (per 1mm thickness) of 10 to 200Kgcm as measured by ASTN G14. A plastic resin composition comprising the above-mentioned thermoplastic resin and various compounding agents to form a plastic layer with such performance;
In particular, it is appropriate to use a polyolefin resin composition.

In this invention, the anti-corrosion coating layer of the anti-corrosion coated steel sheet pile is not particularly limited in the overall thickness or the thickness of each layer, but the thickness of the plastic layer is approximately
The thickness of the adhesive layer is about 0.1 to 2.5 mm, especially 0.2 to 2.0 mm, and the ratio of the thickness of the plastic layer to the adhesive layer is about 0.1 to 2.5 mm, especially 0.2 to 2.0 mm.
The ratio is preferably 20:1 to 1:2, and further,
The thickness of the entire coating layer is approximately 0.5 to 3.5 mm, especially 0.7 to 3.5 mm.
It is preferably about 3.0 mm.

The method for manufacturing the anti-corrosion coated steel sheet pile of this invention is as follows:
For example, the above-mentioned thermoplastic resin, especially a resin plastic material whose main component is polyolefin, is produced from an extrusion molding machine.
These resin plastics are continuously extruded into sheets, cylinders, or other shapes at an extrusion temperature that is above the melting point and up to the melting point plus 150°C, and the pressed material is Plastic sheets, cylinders, etc. are brought into close contact with the surface of steel sheet piles, which are also continuously supplied, along the surface shape, while the sheet-like objects are heated and softened. Any method may be used as long as it forms an anti-corrosion coating layer with a plastic layer as the outermost layer on the surface, or a method in which an uncrosslinked plastic sheet previously extruded into a sheet is laminated onto a preheated steel sheet pile under heating. It may be.

Note that the steel sheet pile used in the above manufacturing method may have its surface subjected to some kind of treatment in advance to improve its resistance to corrosion. In addition, before using the steel sheet pile in the above-mentioned method, mill scale, red rust, dirt, etc. on the surface of the steel sheet pile have been removed by shot blasting, sandblasting, pickling, etc. This is preferable because it increases the bonding force to the sheet pile.
In addition, prior to coating, the surface of the steel sheet pile is treated with chromic acid.
If phosphoric acid treatment and/or epoxy resin primer coating are performed, the adhesion will be even better.

In addition, in the above-mentioned manufacturing method, the coating layer is thermally adhered to the surface of the steel sheet pile and bonded.
It is preferable that the steel sheet pile immediately after the anticorrosive coating layer is cooled to around room temperature (approximately 25° C.) in a relatively short period of time by air cooling, water cooling, or other known cooling methods.

As shown in FIGS. 3 and 4, the anti-corrosion coated steel sheet pile of the present invention has an uncrosslinked plastic layer formed by extruding the surface of a steel sheet pile 2 for civil engineering and construction through a heat-adhesive adhesive layer. It is coated with anti-corrosion coating and has extremely excellent durability and anti-corrosion properties.

In other words, the anti-corrosion coated steel sheet pile of the present invention has heat resistance, impact resistance, weather resistance and durability in the natural environment, and the outermost plastic layer of the coating layer has extremely excellent protective coating. It can be maintained for a long period of time, and it is also resistant to shocks caused by strong contact with stones, gravel, gravel, etc. when steel sheet piles are driven into the ground, or by river water, seawater, and even drifting debris. It is capable of sufficiently resisting impact and erosive force such as being struck by a stick, and furthermore, the adhesive layer existing between the plastic layer and the steel sheet pile adheres closely to the surface of the steel sheet pile. Since the surface of the steel sheet pile is not brought into direct contact with or exposed to water, air, or sunlight, it will remain resistant to corrosion for a long period of time (for example, about 20 years or more, especially about 30 years). (above), it is possible to resist at a high level.

Therefore, the anti-corrosion coated steel sheet pile of the present invention is extremely excellent in durability, corrosion resistance and mechanical properties.

Examples of this invention will be shown below.

Example 1 After preparing the surface of a square-shaped steel sheet pile (manufactured by Nippon Steel Corporation: FSP-type) as shown in Fig. 2 by shot blasting, a chromic acid-based primer and an epoxy resin-based primer were applied. After applying an undercoat paint, the steel sheet piles were heated directly with the flame of a gas burner to about 180°C.

Next, polyethylene (MI: 0.1 g/10
A laminated sheet consisting of adhesive maleated modified polyethylene (0.2 mm thick, density: 0.935 g/cm ³ , thickness: 2.3 mm) is fed while being pulled out at a resin temperature of approximately 200°C, and the laminated sheet is The outer surface of the sheet was sequentially pressed from the center of the steel sheet pile toward both sides using a pressing roll, and then cooled to produce a steel sheet pile with an anticorrosion coating layer consisting of a plastic layer and an adhesive layer.

The peel strength of the anti-corrosion coated steel sheet pile was determined to be 22.0 kg/cm when the peel strength (at 20°C) of the adhesive surface where the laminated coating layer is bonded to the surface of the steel sheet pile was measured according to the ASTM D1000 measurement method. In addition, after the anti-corrosion coated steel sheet piles were cast at an actual seawall construction site, the anti-corrosion coated steel sheet piles were pulled out and observed whether the anti-corrosion coating layer of the anti-corrosion coated steel sheet piles peeled off or was damaged. However, it was confirmed that no defects such as peeling or damage (for example, scratches, bruises, etc.) of the anti-corrosion coating layer of the anti-corrosion coated steel sheet pile occurred.

Furthermore, for the anti-corrosion coated steel sheet pile manufactured by the above-mentioned manufacturing method, ASTM G14
Accordingly, a striking center with a hemisphere at the tip is set to a height of 0.2
When the damage to the coating layer that received the impact was observed by dropping it from a height of In addition, even when the anti-corrosion coated steel sheet pile manufactured by the above-mentioned manufacturing method was subjected to an accelerated indoor 3% saline solution test in which it was immersed in a 3% saline solution at room temperature for a long period of time for about 8000 hours, the coating layer still peeled off. There was no rust on the surface of the steel sheet piles.

〔Effect of the invention〕

As is clear from the above examples, the anti-corrosion coated steel sheet pile of the present invention can be easily handled during actual construction.
During pouring, etc., the coating layer does not peel off or get damaged, and since the tough coating layer acts as a barrier against corrosion, corrosion resistance can be maintained for a long time. Therefore, the service life of the structures (protective shelves, etc.) formed from such steel sheet piles will be significantly extended, reducing maintenance costs such as anti-corrosion repairs, and as a product manufactured in an integrated factory, it is possible to apply anti-corrosive coating in advance. This not only ensures a high level of quality control, but also significantly shortens the construction period in a corrosive environment, resulting in total cost reductions.

[Brief explanation of drawings]

FIGS. 1 and 5 are a perspective view showing an example of a protective shelf formed by driving steel sheet piles into the ground, and a sectional view showing an enlarged partial cross section of the protective shelf. FIG. 2 is a perspective view showing an example of a steel sheet pile used in the present invention. 3 and 4 are cross-sectional views showing the anti-corrosion coated steel sheet pile of the present invention. 1: Protective shelf, 2: Steel sheet pile, 3: Rising part,
4: joint part, 5: anticorrosion coating layer, 6: plastic layer, 7: adhesive layer.

Claims (1)

[Claims] 1. An extruded plastic layer is bonded to at least a portion of one side of the steel sheet pile via a heat-adhesive adhesive layer with a bonding temperature within the range of approximately 50 to 200°C, and an anticorrosion coating is applied. Anti-corrosion coated steel sheet pile with layers formed.