JPS6348697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention uses a specific extrusion coating device to extrude the coating device by feeding the coating device into the coating device and passing it through the interior space of a die. A tubular body of molten plastic resin is continuously extruded around the two-ply steel sheet pile coming out from the inside of the annular discharge opening of the die, and the inside of the tubular body and the above-mentioned internal space are sufficiently filled. By reducing the pressure, the molten tubular body is deformed toward the outer surface around the two-ply steel sheet pile, and then brought into close contact with the outer surface around the steel sheet pile, and the plastic on one side of each steel sheet pile is deformed. The two sheets of steel sheet piles are coated with a continuous anti-corrosion layer using a resin coating layer, and the coating layer that is integrally coated with the two-ply steel sheet pile is cut in the longitudinal direction or a part is removed in the form of a band. Split into steel sheet piles/
The present invention relates to a method of separating and manufacturing anti-corrosion coated steel sheet piles.

(Prior Art) Conventionally, steel sheet piles have been used for civil engineering and construction purposes, but sufficient measures have not always been taken to prevent corrosion.

In general, various types of steel sheet piles for civil engineering and construction are used for the purpose of protecting rivers, coasts, ports, etc. by lining up a large number of steel sheet piles in succession and driving them into the ground to form protective fences, or for construction purposes. It has been used for the purpose of fixing the ground at dredging sites, etc., and preventing mud and sand from flowing into the work site and from collapsing.

In the outdoor natural environment, these steel sheet piles are exposed to water such as river water, wastewater, rainwater, seawater, the atmosphere, sunlight, etc., and are also exposed to soil, sand, etc. during or after pouring.
Because it comes into direct and strong contact with mud, debris, etc., it is extremely susceptible to corrosion, especially when exposed to running water, waves, and the atmosphere.
An environmental place where sunlight and sunlight interact repeatedly,
For example, the above-mentioned corrosion occurs violently near the water surface of ports, estuaries, lakes, etc., but no effective corrosion prevention measures have been taken in the past.
In harbors, estuaries, lakes, etc., the steel sheet piles mentioned above are placed in a continuous row to form a fence to create a seawall, but one side of the fence is covered with waves, quicksand, and drifting debris (driftwood, etc.). In many cases, the steel sheet piles were subject to continuous heavy pounding from ice (drift ice, etc.), wind and snow, and corrosion was especially severe near the water surface of the steel sheet piles. Therefore, even if conventional steel sheet piles are made of highly corrosion-resistant steel materials, they are susceptible to corrosion in the above-mentioned natural environment, and their durability is affected by the corrosion. relatively short and long-term (e.g., about 20 years or more)
It was often not possible to use

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.
FRP coatings were sometimes used, but these were not effective corrosion prevention methods in terms of mechanical strength, long-term durability, and economy (especially workability during coating). .

(Purpose of the Invention) The inventors have studied a method for manufacturing anti-corrosion coated steel sheet piles that can economically and industrially continuously produce steel sheet piles coated with a highly durable anti-corrosion coating. , a tubular body of molten plastic resin is fed through a specific extrusion coating device and is placed around a “double sheet pile” that emerges from the inside of the annular outlet of the extrusion molding die of that coating device. By continuously extruding the tubular body and sufficiently reducing the pressure in both the inside of the tubular body and the inner space of the die of the coating device, the molten tubular body is directed toward the outer surface around the two-ply steel sheet pile. Transform,
It was discovered that an anti-corrosion coated steel sheet pile could be manufactured by bringing the anti-corrosion coated steel sheet pile into close contact with the outer surface thereof, and the method for manufacturing the anti-corrosion coated steel sheet pile of the present invention was completed.

(Structure of the Invention) That is, the plastic resin has an annular discharge port capable of extruding the plastic resin into a tubular shape, and also allows the long steel sheet piles to be coated to freely pass through in the longitudinal direction in a stacked state. The extrusion coating is carried out by using an extrusion coating device which is provided with an extrusion molding die in which a sufficient internal space passes through the inside of the discharge port from the rear, and which is capable of sufficiently reducing the pressure in the internal space. Two long steel sheet piles are supplied in a stacked state by a support device and a feeding device for long steel sheet piles attached to the device, and the extrusion forming die of the extrusion coating device is coated from behind the extrusion molding die. around the moving two-ply steel sheet pile that moves within the internal space toward the discharge port of the ring, passes through the die and emerges from the inside of the annular discharge port,
A tubular body of plastic resin is continuously extruded from the discharge port of the die, and at the same time, the pressure inside the tubular body and the internal space is sufficiently reduced, and the tubular body of plastic resin in a molten state is extruded into two layers of steel. The outer surface of the sheet piles is deformed and brought into close contact with each other, one side of each steel sheet pile is continuously coated with a plastic resin coating layer, and finally, the two sheets of steel sheet piles are coated in one piece. This invention relates to a method for manufacturing an anti-corrosion coated steel sheet pile, characterized in that two places on both sides of the coating layer are cut along the longitudinal direction of the steel sheet pile or a part thereof is removed in a band shape to separate the steel sheet piles with respective anti-corrosion coating layers.

The manufacturing method of this invention uses an extrusion coating method,
It is possible to form an anti-corrosion coating layer made of plastic resin with excellent performance on the entire surface (including concave and convex surfaces) on one side of each of various two-ply steel sheet piles, and furthermore, it is possible to form an anti-corrosion coating layer made of plastic resin with excellent performance. This is a completely new method for producing anti-corrosion coated steel sheet piles, which has extremely high productivity and can continuously and stably manufacture two coated steel sheet piles at a time.

The anti-corrosion coated steel sheet pile manufactured by the manufacturing method of the present invention is a plastic sheet pile that has consistently excellent mechanical strength, durability, anti-corrosion properties, etc., and also has a uniform thickness and smooth surface condition. This steel sheet pile has an excellent anti-corrosion coating layer formed from a stainless steel layer, and is an excellent anti-corrosion coated steel sheet pile that exhibits corrosion protection that is effective for an extremely long period of time.

(Embodiments and Effects of the Invention) Hereinafter, the method for producing an anti-corrosion coated steel sheet pile of the present invention will be described in more detail based on embodiment examples shown in the drawings.

FIG. 1 is a cross-sectional view schematically showing a longitudinal cross section of the vicinity of an extrusion molding die of an example of a coating device used in the manufacturing method of the present invention, and FIG. 2 is a sectional view of an example of the coating device used in the manufacturing method of the present invention. FIG. 2 is a front view schematically showing the vicinity of an extrusion molding die.

Fig. 3 is a sectional view showing the two-ply steel sheet pile coated with resin from the extrusion coating device in the manufacturing method of the present invention, and Fig. 4 shows the coating layer of the coated two-ply steel sheet pile. It is a sectional view showing a state in which two parts of the steel sheet pile are cut and removed and separated into respective corrosion-resistant coated steel sheet piles.

Figure 5 shows a large number of steel sheet piles lined up and driven into the ground.
FIG. 6 is a perspective view showing an example of a general state in which a protective fence is formed, and FIG. 6 is a perspective view showing an example of a steel sheet pile used in the present invention.

As shown in FIGS. 1 and 2, the extrusion coating apparatus used in the manufacturing method of the present invention includes (a) a crosshead-type die 3 having an annular discharge port 1 capable of extruding plastic resin into a tubular shape; (b) Moreover, an internal space 2 of sufficient width through which the two-ply steel sheet pile 11 to be coated can freely pass through from the rear of the die 3 to the inside of the discharge port 1. An extrusion molding die 3 is provided, and (c) a suction device for sucking the gas in the internal space with a vacuum pump (not shown) so that the internal space 2 of the die 3 can be sufficiently reduced in pressure. Preference is given to an extrusion coating device in which channels 4, 4' are provided.

In the extrusion coating apparatus, for example, as accessory equipment for supplying the two-ply steel sheet pile 11 to be inserted toward the internal space of the extrusion molding die 3 of the extrusion coating apparatus and maintaining its advancing direction and position, As shown in FIG. 1, a support member 5 for supporting the steel sheet pile and determining the direction of movement of the steel sheet pile is integrally installed at the rear of the die, and furthermore, the two-ply steel sheet pile is transferred to the coating device. Preferably, a number of supply rolls 7 (not shown in the drawing, at least one of which is connected to a drive) are additionally provided for supply.

The support member 5 is fitted into the rear part of the die 3, and the rear opening of the internal space 2 of the die 3 is opened to such an extent that movement (penetration) of the two-ply steel sheet piles is not hindered. In order to sufficiently reduce the pressure in the inner space 2 of the die 3, it is appropriate that the inner space of the die 3 is closed and the inner space thereof is appropriately sealed.

The annular discharge port 1 has an annular shape, if it is possible to open an internal space having an inner circumference larger than the outer circumference of the two-ply steel sheet pile so that the two-ply steel sheet pile can pass through with a margin. The shape of the outlet is not particularly limited, and in addition to the annular shape shown in FIG. Opening a hexagonal or octagonal annular discharge port, or an internal space that corresponds to and approximates the outer circumferential shape of the two-ply steel sheet pile to be coated and has an inner circumference larger than the outer circumferential shape of the two-ply steel sheet pile. It may be an annular discharge port.

The die of the extrusion coating apparatus described above may be of any type as long as it has the above-mentioned requirements, for example, a double U-shaped steel sheet pile 11 as shown in FIG. An internal space 2, which is larger than the outer circumferential shape of the cross-section of the die, is opened inside the die and allows the steel sheet piles to pass through it fairly freely in the longitudinal direction, and an elliptical manifold 10 is located at the rear of the die. An annular discharge port 1 capable of extruding plastic resin into a tubular shape is connected to a manifold 10 by a resin passage 13, and resin is supplied from an extruder (not shown) to the manifold 10. Any device to which the supply path 8 is connected may be used.

It is preferable that a plurality of the plastic resin supply channels be provided corresponding to the outer peripheral shape of the two-ply steel sheet pile, and in particular, if necessary, a complex shape such as the joints at both ends of the steel sheet pile can be provided. Another resin supply path may be connected to a portion corresponding to the portion having the resin.

In the manufacturing method of the present invention, the extruder attached to the extrusion coating apparatus may be any conventionally known extruder, and the above-mentioned plastic resin supply channels 8 and 8 may be used.
A plurality of extruders may be provided for each extruder, or a plurality of supply paths for the plastic resin may branch from one extruder and be connected to the manifold.

In the manufacturing method of the present invention, first, the above-mentioned extrusion coating device is used, and the feeding direction of the steel sheet piles is adjusted by the steel sheet pile supporting device and the feeding device attached to the coating device. , feeding the two-ply steel sheet pile 11 to the coating device, and moving the inside of the internal space 2 from the rear of the extrusion molding die 3 toward the annular outlet 1 of the die 3; A tubular body 6 of plastic resin in a molten or softened state is continuously extruded around the moving and progressing two-ply steel sheet pile 11 coming out from the inside of the discharge port 1 through the pipe. The inner side 9 of the body 6 and the internal space 2 of the die 3 are both sufficiently depressurized to deform the molten or softened plastic resin tubular body 6 toward the outer circumferential surface of the two-ply steel sheet pile 11 and bring it into close contact. Then, the surrounding outer surface of the two-ply steel sheet pile is continuously coated with a plastic resin coating layer to prevent corrosion.

In the manufacturing method of this invention, around the two-ply steel sheet pile 11 that is moving and progressing through the inside of the die 3 and coming out from the inner opening of the discharge port 1,
The plastic resin tubular body 6 is continuously extruded, and at the same time, the inside 9 of the tubular body 6 and the internal space 2 of the die 3 are sufficiently depressurized to stack two molten plastic resin tubular bodies 6 together. deforming the steel sheet pile 11 toward the outer surface thereof,
It is important to ensure close contact, and the degree of pressure reduction depends on the type of plastic resin used, its basic physical properties, the outer shape of the two-ply steel sheet pile to be coated, and extrusion molding conditions. For example, when using a polyolefin resin as described below, the pressure is preferably about 0.9 atm or less, particularly about 0.5 to 0.85 atm, more preferably about 0.6 to 0.8 atm.
The pressure during the above decompression is atmospheric pressure (normal pressure; 1 atm)
If the temperature is too close to , the molten plastic tubular body may deform toward the outer surface of the two-ply steel sheet pile and may not adhere tightly, which is undesirable, and the pressure at the time of decompression will be too low. If it is too long, it is not preferable because the molten plastic resin tubular body may become significantly uneven in thickness or break during deformation before coming into close contact with the surrounding outer surface of the two-ply steel sheet pile.

In the manufacturing method of this invention, when the thickness (A) of the plastic resin tubular body immediately after being extruded from the annular discharge port 1 of the die 3 is in close contact with the outer surface around the two-ply steel sheet pile. The ratio of the thickness (B) of the tree cover layer (value of B/A. Also referred to as the withdrawal ratio).
is suitably about 0.1 to 0.8 on average, particularly about 0.2 to 0.7. If the above-mentioned drawdown ratio becomes too close to 1, the molten plastic resin tubular body will form convex wrinkles along the longitudinal direction of the steel sheet pile, and the surface of the steel sheet pile will have wrinkles. This is unsuitable because the coating layer remains tightly adhered to the surface and does not have a smooth surface. Also, if the draw-down ratio is too small, the tubular body may become uneven in thickness or break, which is undesirable. In addition, in the manufacturing method of this invention, for example, it is most preferable to adjust the draw-down ratio by appropriately adjusting the discharge speed of the resin and the moving speed of the two-ply steel sheet pile.

In addition, in this invention, the lip interval of the annular discharge port 1 of the extrusion molding die 3 of the coating device is the lip interval at the part corresponding to the concave part on the outer peripheral surface of the two-ply steel sheet pile, and the lip interval at the part corresponding to the other convex part. It is preferred that the rip spacing be significantly larger than the rip spacing of .

The steel sheet piles used in the manufacturing method of this invention are generally those used for civil engineering and construction purposes, such as arranging a large number of them and driving them into the ground to form a protective fence, as shown in Figure 5. It may be of any length or shape, for example, H-shape, L-shape, U-shape, etc.
Any type of steel sheet pile with a cross-sectional shape such as type, Z-type, or construction type may be used.In particular, typical steel sheet piles are those with a cross-sectional structure of approximately 〓-type as shown in Fig. 6. A long body having a main body and joint parts bent outward to form grooves with a small inner diameter on the rising parts (sometimes called flanges) on both sides. Examples include steel plate structural materials.

In the manufacturing method of this invention, the size of the steel sheet pile,
And no matter what shape the steel sheet pile has, it can be used without replacing the die of the extrusion coating device. That is, in the manufacturing method of the present invention, especially if the extrusion molding die of the above-mentioned coating apparatus has a circular annular outlet or an elliptical annular outlet, one type of die can It has the advantage of being able to be used with steel sheet piles of a wide variety of shapes and sizes.

In the manufacturing method of this invention, the two-ply steel sheet piles may be stacked in any way, but in order to easily supply them stably to the extrusion coating equipment and to provide corrosion-resistant coating with good reproducibility, it is necessary to As shown in Fig. 3, it is most suitable that the convex portions of one steel sheet pile are fitted into the concave portions of the other sheet piles so that they are stacked one on top of the other.

In this invention, when the steel sheet pile is used for coating, it is preferable that a suitable adhesive layer be provided on the outer surface of the steel sheet pile to be coated.

The adhesive layer provided on the surface of the steel sheet pile has an adhesive temperature within the range of approximately 50 to 200°C, and the plastic resin layer is heat-bonded to the surface of the steel sheet pile with an appropriate adhesive force. It may be made of any type of adhesive as long as it is adhesive, for example, it may be made of an olefin-based (co)polymer as the main component, or it may be made of the above-mentioned (co)polymer and a tackifier. Heat-fusible adhesives (such as hot-melt adhesives) or heat-curable adhesives that maintain appropriate elasticity or flexibility after bonding but do not become too hard after bonding. It is an adhesive that does not become stiff or brittle, and has excellent adhesion to the steel sheet surface after coating the surface of the steel sheet pile with a plastic resin layer (180 degree peeling, tensile speed 10 mm/min, 20°C)
It is preferable that the adhesive is made of an adhesive having a weight of about 2 kg/cm or more, particularly about 4 to 20 kg/cm.

Examples of olefinic (co)polymers used in such adhesives include polyethylene, polypropylene, polyvinyl chloride, ethylene/vinyl acetate copolymer, ethylene/propylene copolymer,
Examples include ethylene/lower alkyl (meth)acrylate copolymers, ethylene/(meth)acrylic acid copolymers, and modified polymers thereof (e.g., maleated polyethylene, maleated polypropylene, etc.), which may be used alone. Alternatively, it may be used as a mixture of two or more types.

The tackifier can be arbitrarily selected from tackifiers commonly used in known adhesive compositions, and examples of the tackifier include rosin and rosin derivatives, Examples include pinene resin, coumaron resin, coumaron-indene resin, other aliphatic or alicyclic hydrocarbon resins, and aromatic hydrocarbon resins.

In addition to the above-mentioned components, the adhesive layer also contains inorganic fillers such as talc, charcoal, silica, alumina, mica, and carbon black, or additives such as antioxidants, colorants, and softeners. ,
Furthermore, as corrosion inhibitors, for example, inorganic corrosion inhibitors such as metal chromates, metal phosphates, metal phosphites, metal nitrites, metal salts of aromatic carboxylic acids, and multiple hydroxyl groups. Organic corrosion inhibitors such as aliphatic or aromatic compounds and tannic acid may also be added.

Plastic resins used in this invention include, for example, polyethylene, polypropylene, ethylene and propylene copolymers, olefinic polymers such as ethylene/vinyl acetate copolymers, polyvinyl chloride, polyesters, polyamides, and other plastics. Resins, especially melt viscosity (measured using a high shear viscometer, at a temperature of 230
℃, the measured value at a shear rate of 1 sec ^-1 ) is 10 to 10 ⁸ poise, and the melt tension (measured using a melt tension meter; inlet angle of 60 degrees, at a measurement temperature of 230℃ and an extrusion speed of 10 mm/min). measurement) is 0.5~30g, especially 1.0~
25 g of the plastic resin described above is preferred.

The plastic resin for forming the above-mentioned coating layer may contain other polymers, known plasticizers, antioxidants, flame retardants, various colorants, fillers (carbonaceous,
silica, carbon black, etc.) may be blended.

The plastic coating layer has a tensile strength of 50 to 300 after being coated on the surface of the steel sheet pile.
Kg/cm ² and has an impact resistance (per 1 mm thickness) of 10 to 200 Kg/cm as measured by ASTMG14. An extrusion coating method under appropriately selected molding conditions using a plastics resin composition, especially a polyolefin resin composition, which is made of the above-mentioned plastics resin and various other compounding agents to form a coating layer with such performance. It is desirable that the

In this invention, the temperature of the plastic resin extruded in an annular shape from the outlet of the die of the extrusion coating device is within the range of not less than the melting point of the plastic resin and up to the melting point plus 150°C. Any temperature is sufficient.

In this invention, the plastic resin is
If the melt viscosity or melt tension is too low, the plastic resin tubular body extruded from the extrusion coating device will be abnormally deformed due to the reduced pressure in the internal space of the die, and the surrounding area of the two-ply steel sheet pile will deteriorate. This is undesirable because it makes it difficult to form a uniform coating layer on the outer surface, and if the melt viscosity or melt tension is too high, the plastic resin tubular body extruded from the extrusion coating device may become rough. If the inner space is not sufficiently deformed and does not adhere to the surface of the recessed part of the steel sheet pile due to the reduced pressure in the internal space, or if the pressure is forcibly reduced in such a case, the tubular body may break and cracks may occur. It is not appropriate because it can be done.

In the manufacturing method of this invention, it is appropriate that the steel sheet pile coated with plastic resin has an adhesive layer on the surface to be coated. It may be formed using a method.

In the manufacturing method of the present invention, the anticorrosion coating layer of the two-ply steel sheet pile coated with the anticorrosion coating obtained by the present invention is made of plastic, although the overall thickness and the thickness of each layer are not particularly limited. The thickness of the resin layer is about 0.2 to 5.0 mm, the thickness of the adhesive layer is about 0.05 to 2.0 mm, and the ratio of the thickness of the plastic resin layer to the adhesive layer is 1. :2~
The ratio is preferably 100:1, and the thickness of the entire coating layer is about 0.4 to 6.0 mm, particularly 1.0 to 3.5 mm.
Preferably, it is about mm.

In addition, the steel sheet pile having the adhesive layer continuously supplied for coating in the manufacturing method of the present invention has its surface subjected to some kind of treatment before the adhesive layer is formed on the surface. It may also have improved corrosion resistance. In addition, the plastic resin layer should be removed from the steel sheet pile by shot blasting, sandblasting, pickling, etc. to remove mill scale, red rust, dirt, etc. before coating with adhesive. This is preferable because it increases the bonding force to the steel sheet pile through the agent layer. In addition, if the surface of the steel sheet pile is treated with chromic acid, phosphoric acid, and/or coated with an epoxy resin primer before coating the surface of the steel sheet pile with an adhesive layer, the adhesion and corrosion resistance will be further improved. Become good.

In the manufacturing method of the present invention, as described above, the two-ply steel sheet pile coated by the extrusion coating device can be made into two-ply steel sheet piles as shown in FIG.
The outer surface of the surrounding area is covered with a continuous resin coating layer, which is stacked together, and if necessary, the coated two-ply steel sheet piles can be cooled using a known cooling method. Finally, after cooling the steel sheet piles to around normal temperature, the two appropriate places on both sides of the coating layer around the two-ply steel sheet piles (in the case of Fig. 3, the overlapped joints on both sides of each steel sheet pile) The coating layer is cut along the longitudinal direction of each steel sheet pile using various cutting tools such as a cutter, a knife, a cutting device with a rotary blade, a hot wire cutting device, a laser beam cutting device, etc. However, if necessary, parts of the coating layer that are not particularly necessary (for example, the outer surface of the joints of steel sheet piles) are peeled off and removed, and a corrosion-resistant coating layer as shown in a and b in Figure 4 is removed. 12 or 12' is divided and separated into two corrosion-resistant coated steel sheet piles each having a concave or convex surface of the steel sheet pile.

In addition, when peeling off the above-mentioned unnecessary portion of the coating layer, it is preferable to apply a release agent in advance to the peeling portion of the two-ply steel sheet pile to be coated.

The manufacturing method of this invention involves continuously supplying two piles of various steel sheet piles and continuously forming an anti-corrosion coating layer on the outer surface around the steel sheet piles (on one side of each sheet pile). This is a method for producing corrosion-resistant coated steel sheet piles that can continuously produce two types of steel sheet piles having excellent corrosion-resistant coating layers two at a time with high productivity.

The anti-corrosion-coated steel sheet pile obtained by the manufacturing method of this invention has a plastic resin layer (if necessary, a heat adhesive layer is applied) on the concave and convex surfaces of the steel sheet pile for civil engineering and construction. ) Since they are joined together to form an anti-corrosion coating layer, they have extremely high impact resistance, weather resistance and durability against natural environments, and steel sheet piles are actually used at construction sites in civil engineering and construction. For example, when a steel sheet pile is driven into the ground, it may come into strong contact with stones, gravel, gravel, etc., or it may be struck by river water, seawater, or even drifting objects. It can sufficiently resist erosion forces, and furthermore, the plastic resin layer (optimally with an adhesive layer) is in close contact with the surface of the steel sheet pile and protects it. Ori,
Do not allow the surface of steel sheet piles to come into direct contact with or be exposed to water, air, or sunlight for long periods of time (e.g.
It shows a high level of corrosion protection performance for more than 20 years, especially for more than 30 years.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing a longitudinal cross section of the vicinity of an extrusion molding die of an example of a coating device used in the manufacturing method of the present invention, and FIG. 2 is a sectional view of an example of the coating device used in the manufacturing method of the present invention. FIG. 2 is a front view schematically showing the vicinity of an extrusion molding die. Fig. 3 is a cross-sectional view showing the situation of the two-ply steel sheet piles coated from the extrusion coating device in the manufacturing method of the present invention, and Fig. 4a and b are the coated two-ply steel sheet piles. FIG. 2 is a sectional view showing a state in which two parts of the coating layer are cut and a portion is removed, and the steel sheet piles are separated into respective corrosion-resistant coated steel sheet piles. FIG. 5 is a perspective view showing an example of a state in which a large number of steel sheet piles are lined up and driven into the ground to form a protective fence, and FIG. 6 is a perspective view showing an example of a steel sheet pile used in the present invention. It is. 1: Discharge port of extrusion molding die, 2: Internal space of extrusion molding die, 3: Extrusion molding die, 4: Gas suction path, 5: Support member of two stacked steel sheet piles,
6: Plastic resin tubular body, 7: Two-ply steel sheet pile supply roll, 8: Resin supply path, 9:
Inside of resin tubular body, 10: Manifold, 1
1: steel sheet pile, 12: coating layer, 13: resin road.

Claims (1)

[Scope of Claims] 1. It has an annular discharge port that can extrude plastic resin into a tubular shape, and can freely pass through two long steel sheet piles to be coated in the longitudinal direction in a stacked state. The extrusion coating is carried out by using an extrusion coating device which is provided with an extrusion molding die in which a sufficient internal space passes through the inside of the discharge port from the rear, and which is capable of sufficiently reducing the pressure in the internal space. The steel sheet piles are supplied in a stacked state by a steel sheet pile supporting device and a feeding device attached to the device, and the steel sheet piles are fed from the rear of the extrusion molding die of the extrusion coating device to the discharge port of the die. around the moving two-ply steel sheet pile that moves within the interior space and passes through the die and emerges from inside the annular discharge port thereof;
A tubular body of plastic resin is continuously extruded from the discharge port of the die, and at the same time, the pressure inside the tubular body and the internal space is sufficiently reduced, and the tubular body of plastic resin in a molten state is extruded into two layers of steel. The outer surface of the sheet piles is deformed and brought into close contact with each other, one side of each steel sheet pile is continuously coated with a plastic resin coating layer, and finally, the two sheets of steel sheet piles are coated in one piece. A method for producing an anti-corrosion coated steel sheet pile, which comprises cutting or partially removing the coating layer in two places along the longitudinal direction of the steel sheet pile in the form of a band, and separating the steel sheet piles into respective steel sheet piles with anti-corrosion coating layers.