JP3213936B2 - Heavy-corrosion-coated steel sheet pile and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy duty anti-corrosion coated steel sheet pile having a heavy duty anti-corrosion coating formed on the surface of a steel sheet pile by laminating a polyethylene sheet, and more particularly to a method of manufacturing the same. TECHNICAL FIELD The present invention relates to a heavy-duty anticorrosion-coated steel sheet pile excellent in long-term adhesion between the steel sheet piles and a method for producing the same.

[0002]

2. Description of the Related Art Steel sheet piles forming quays of oceans, harbors, rivers, etc. are exposed to a severe corrosive environment. Therefore, a sheet made of polyolefin resin such as polyethylene or polypropylene is adhered to the surface of the sheet piles via an adhesive layer. By doing so, so-called heavy-corrosion-coated steel sheet piles that have been subjected to corrosion protection have been increasingly used.

[0003] This heavy duty steel sheet pile is disclosed in
As disclosed in Japanese Patent No. 24717 or Japanese Patent Application Laid-Open No. 60-8058, a base treatment layer consisting of a chemical conversion treatment layer, a primer layer and the like is formed on a steel sheet pile whose base has been adjusted, and then a modified polyolefin or the like is bonded. Through the agent layer,
It is known that a method in which a corrosion-resistant polyolefin layer is formed and a sheet-shaped corrosion-resistant polyolefin layer is attached to a preheated steel sheet pile to produce the same. In some cases, a sheet in which the modified polyolefin layer and the anticorrosion polyolefin layer are integrated is coated. It is also known to provide a band-shaped sealing layer at the end of the heavy corrosion protection coating in order to prevent deterioration due to permeation of seawater or the like from the edge of the coating (Japanese Patent Application Laid-Open No. 60-233232).

[0004]

However, the polyethylene-coated steel sheet pile manufactured by sticking the sheet, when exposed to the marine environment for a long time after casting, has a problem in that the adhesive force between the steel materials of the sheet, particularly in the middle of the sea. In the worst case, the coating may be lifted or turned over.

[0005] In recent years, the design life of harbor facilities and the like has also been prolonged, and in view of the current situation in which it is desired to reduce the maintenance costs during that time, the long-term adhesion of the coating of the heavy corrosion-resistant coated steel sheet pile is further improved. This is a very significant issue that can produce enormous economic effects.

[0006] One of the causes of the decrease in the adhesion strength of the heavy-corrosion coated steel sheet pile in seawater is that the sheet is attached to one side of the steel sheet pile having a curved surface due to the invasion of environmental substances from the end of the sheet. In some cases, the adhesive layer and the undercoat layer may be easily deteriorated.

The above-mentioned method of providing a band-shaped sealing layer at the covering end is a countermeasure. However, the band-shaped sealing layer easily deteriorates and falls off in seawater, and it is difficult to achieve a sufficient sealing effect. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in particular, prevents the permeation of moisture from a coating end portion in seawater to improve the long-term adhesion of the coating layer in seawater. An object of the present invention is to provide an excellent heavy-corrosion-coated steel sheet pile.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to improve the adhesion of the belt-shaped sealing layer and to develop a heavy duty anti-corrosion coated steel sheet pile having excellent long-term adhesion in seawater.
As a result, they have found that when a seal made of a moisture-curable resin, particularly a moisture-curable urethane resin, is immersed in seawater for a long period of time, it does not fall off and performs its sealing function for a long period of time. Further, it is possible to improve the long-term adhesion of the belt-shaped sealing layer in seawater by priming the site where the belt-shaped sealing layer is to be provided with a heavy corrosion protection paint, and that the heavy corrosion protection coating comprises a polyolefin layer and the modified polyolefin layer It was also found that the long-term adhesion of the belt-shaped sealing layer in seawater could be improved by projecting and exposing the modified polyolefin layer from the coating end when the sheet was adhered to a steel sheet pile as an adhesive layer.

That is, the present invention is characterized in that, in a steel sheet pile provided with a heavy-duty corrosion protection coating, a band-shaped sealing layer made of a moisture-curable urethane resin is provided at an edge of the heavy-duty corrosion protection coating. A heavy corrosion protection coated steel sheet pile, a steel sheet pile provided with a heavy corrosion protection coating, wherein a belt-shaped sealing layer is provided at an edge portion of the heavy corrosion protection coating via a heavy corrosion protection paint film. In a steel sheet pile, and in a steel sheet pile to which a heavy corrosion protection coating is applied, the heavy corrosion protection coating is composed of a modified polyolefin layer and a polyolefin layer, and at the edge of the heavy corrosion protection coating, the edge of the modified polyolefin layer is outside the polyolefin layer. The present invention relates to a heavy-duty coated steel sheet pile characterized in that a belt-shaped sealing layer is provided on the edge.

The reason that a moisture-curable urethane resin can fulfill a sealing function in seawater for a long period of time is that it is a moisture-curable urethane resin which has a urethane bond and a urea bond in the molecule and thus has excellent water resistance and moderate flexibility. It is presumed that due to its properties, it did not deteriorate even in seawater and adhered sufficiently to the side edges, and was not easily affected by attached organisms.

The heavy-duty anticorrosion paint film alone has excellent water resistance and corrosion resistance so that it can be used for anticorrosion of steel materials, and has an effect of remarkably reducing the penetration of moisture from the end. In addition, the heavy corrosion protection paint film and the moisture-curable urethane are used in combination to prevent the heavy corrosion protection paint film from being damaged, cracked or dropped. Further, the modified polyolefin layer has good adhesion to the sealing material and the heavy-duty anticorrosion paint, and by exposing the modified polyolefin layer, the effective adhesion area of the sealing material and the heavy-duty anticorrosion paint is increased, and the adhesion is excellent.

[0013]

Embodiments of the present invention will be described below in detail. As shown in FIG. 1, the heavy-corrosion-coated steel sheet pile of the present invention has a steel sheet pile 1, a base treatment layer 2, an adhesive layer 3, a corrosion protection layer 4,
It is composed of an end seal layer 5.

The steel sheet pile used in the present invention is a port, a river,
Used for revetment of landfills, etc.
U-shaped, Z-shaped, and I-type prescribed in 5528, and those conforming to them. There are no particular restrictions on its dimensions. In the present invention, heavy anticorrosion coating is applied to a portion where anticorrosion needs to be applied. For example, when used for seawall protection in harbors, the coating is often applied mainly to the side facing the sea, but it goes without saying that heavy corrosion protection coating can be applied to both sides of the steel sheet pile. Further, in combination with the cathodic protection, the heavy anticorrosion coating is usually applied to a limited area of about LWL-1 m from the sea atmosphere.

The steel sheet pile used in the present invention is previously subjected to a known base treatment such as degreasing, pickling, shot blasting, grit blasting, and sand blasting to remove oil, scale, and the like on the surface of the steel material. It is desirable. The level of the substrate adjustment is preferably, for example, about Sa2 1/2 or more in the Swedish standard (SIS). If the substrate adjustment is insufficient, the long-term anticorrosion of the heavy duty anticorrosion coating is significantly impaired. Furthermore, long-term adhesion can be achieved by performing a chemical conversion treatment such as a known chromate treatment.
It is preferable from the viewpoint of anticorrosion properties.

The primer layer used in the present invention is an epoxy resin-based or urethane resin-based organic resin-based primer having excellent adhesion between the surface of the steel sheet pile whose base material has been adjusted and the modified polyethylene layer. Used. The primer layer is formed by a known coating method such as air spraying, airless spraying, brush coating, or the like, and if necessary, heated after coating to form a complete cured film. The thickness of the primer layer is about 10 to 200 μm, especially 20 to 1 μm.
It is preferably about 00 μm. If the thickness is less than 10 μm, the adhesion between the polyethylene sheet and the steel material becomes small, and there is a problem that the polyethylene sheet is peeled off.
When the thickness exceeds 0 μm, the residual stress of the primer layer itself increases, which adversely affects the long-term adhesion of the sheet.

The adhesive layer is a layer for adhering the anticorrosion layer, and comprises a modified polyolefin resin when a polyolefin sheet is used as the anticorrosion layer, and an epoxy-based primer or a urethane-based primer when using a urethane elastomer or the like as the anticorrosion layer. .

The modified polyolefin is obtained by modifying a polyolefin resin with an unsaturated carboxylic acid such as maleic acid, acrylic acid or methacrylic acid or an anhydride thereof by a graft reaction or the like. Refers to a resin having significantly improved adhesion to the resin. Modified polyolefins are known to have various thermal properties depending on the type and amount of functional groups to be grafted, but the Vicat softening point of the modified polyolefin used in the present invention is 50%.
Those having a temperature of from 90 ° C to 90 ° C are preferred. If the softening point is 50 ° C or less, the adhesiveness of the sheet is lowered in the aerial part of the heavy-duty corrosion-resistant steel sheet pile due to temperature rise due to sunshine or the like. However, the increase in the required heating temperature of the steel sheet pile causes an increase in energy cost, which is not preferable. A more preferred Vicat softening point is 55 to 80 ° C, particularly preferably 55 to 70 ° C. According to the study of the present inventors, the modified polyethylene layer has a Vicat softening point of 9%.
It was found that when the temperature was 0 ° C. or less, the generated stress was small. However, it was found that if the modified polyethylene had a Vicat softening point of 70 ° C. or less, the residual stress would be extremely small. However, if the softening point is too low, there is a danger that the modified polyethylene layer will reach the softening point in the aerial part, especially during sunshine in summer, and the adhesion will be reduced.

Other properties of the modified polyethylene include a melt index of about 0.2 to 10 g / 10 minutes, preferably about 0.5 to 5 g / 10 minutes, and a density of 0.8.
Those having a concentration of about 5 to 0.98 g / cm ³ and a melting point of about 60 to 100 ° C, preferably about 60 to 80 ° C are suitable.
The thickness of the modified polyethylene layer is about 0.1 to 1.5 mm,
Preferably, about 0.2 to 1 mm is appropriate.

The anticorrosion layer is made of polyolefin, urethane elastomer, rubber lining or the like.

Polyolefin resins include known polyolefins such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene and polypropylene, and known polyolefin copolymers such as ethylene-propylene random or block copolymers. It is united.

A particularly preferred polyolefin is a so-called high-density polyethylene having a density of 0.940 g / cm ³ or more. For the purpose of improving environmental stress crack resistance, impact resistance, and toughness, an ethylene copolymer containing a polyolefin-based component such as propylene, butene-1, hexene-1, or the like as a copolymer component can also be used. The upper limit of the density is not limited, but the upper limit of the commercial product is usually about 0.970 g / cm ³ . Particularly preferred density is about 0.940 to 0.960 g / cm ³ . The melt index is preferably 0.3 g / 10 min or less, and preferably about 0.1 to 0.3 g / 10 min. If it exceeds 0.3 g / 10 minutes, environmental stress and cracking properties are undesirably reduced. The Vicat softening point is 10
Those having a temperature of about 0 to 130 ° C, particularly about 110 to 125 ° C, are preferred. The preferred softening point difference from the modified polyolefin layer is about 10 to 70 ° C.

The thickness of the anticorrosion polyolefin layer is 1 to 6 mm
The thickness is preferably in the range of about 1 to 4 mm from the viewpoints of long-term adhesion, long-term corrosion resistance, and maintenance of the mechanical strength of the coating layer. Incidentally, the standard of the anticorrosion polyolefin of the heavy-corrosion protection steel sheet pile is set to 2.0 mm or more, and the thickness of the anticorrosion polyolefin layer is often 2.0 mm or more.

In addition, several cross-linking methods such as electron beam cross-linking, silane cross-linking, and chemical cross-linking are known for polyethylene, and these cross-linked polyethylenes are generally used for heavy-duty corrosion-resistant steel sheet piles. No cross-linked polyethylene is used, and non-cross-linked polyethylene is used. This is because the effect of relaxing the stress after cooling is not impaired.
On the other hand, since high-density polyethylene is used, it has sufficient mechanical strength, so that it is not necessary to take a crosslinked structure.

The urethane elastomer is formed using isocyanate compounds and polyol compounds as raw materials. Isocyanate compounds are those having two or more isocyanate groups, tolylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, lysine isocyanate methyl ester and these Modified derivatives and the like.

Examples of the polyol include bifunctional or trifunctional polyols such as polyether polyol, polyester polyol, polyesteramide polyol, acrylic polyol, castor oil-modified polyol, epoxy-modified polyol, polyalkylene glycol, and terminal OH polybutadiene.

The polyvalent amine compound as a curing agent includes, for example, methylene orthochloroaniline,
Examples thereof include, but are not limited to, diaminodiphenylmethane, ethylenediamine, diethylenetriamine, hydrazine, isophoronediamine, and triethylenetetramine.

The compounding ratio of the isocyanate compound and the polyol is 0.85 to 0.85 in the molar ratio of NCO / (OH + NH ₂ ).
About 1.5 is appropriate.

These urethane elastomer layers are usually applied by a two-liquid mixing type airless spray, and are applied several times to obtain a desired film thickness. The thickness of the urethane elastomer layer is suitably in the range of 1 to 20 mm.
About 10 to 10 mm, particularly preferably about 1.5 to 4 mm.
When the film thickness is 1 mm or less, there is a problem that the strength of the urethane elastomer layer is reduced, so that the anticorrosion performance is reduced. When the film thickness is 20 mm or more, peeling or cracking due to an increase in the residual stress of the urethane elastomer layer is caused. There are problems such as.

Various additives such as carbon black, titanium oxide and other pigments, and antioxidants can be added to the polyolefin layer and the urethane elastomer layer in order to improve weather resistance and other properties. The amount of the pigment added is suitably 10 to 80% by weight, preferably about 30 to 60% by weight, and the amount of the antioxidant is 0.1 to 3% by weight.
Level, preferably about 0.5 to 2% by weight.

The rubber lining layer is made of neoprene rubber,
Synthetic rubber such as butyl rubber, nitrile rubber and chloroprene rubber, natural rubber, rubber made of urethane resin, and the like are used.

The heavy duty anticorrosion coating is often provided on one side of the steel sheet pile, but may also be provided on both sides. However, in any case, since the heavy corrosion protection coating is not usually applied to the grip portions on both side edges of the steel sheet pile, the heavy corrosion protection coating has an edge portion. The present invention is characterized in that a belt-shaped sealing layer provided on this edge portion of the heavy-duty anticorrosion coating is devised.

The belt-shaped sealing layer includes silicone, modified silicone, polysulfide, polyurethane,
An elastic sealing material such as an aqueous acrylic, butyl, or styrene-butadiene copolymer rubber, or an inelastic sealing material such as a glass putty, an oil-based caulking material, or an asphalt-based resin can be used. It is preferable to provide a product, preferably a moisture-curable urethane resin composition. Moisture-curable urethane resin composition is a urethane bond obtained by reacting a polyisocyanate such as tolylene diisocyanate, hexamethylene diisocyanate, methylene diphenyl diisocyanate with a polyhydric alcohol such as a polyester polyol or a polyether polyol, and partially free urethane bonds. It is a prepolymer having isocyanate groups, and when applied as an end seal material, the free isocyanate groups react with moisture in the air to form urea bonds to form a three-dimensional infinite stitch structure. Form and cure. Since this seal layer is composed of a urethane bond and a urea bond, it has extremely excellent resistance to water deterioration, and exhibits a function as a seal material for a long time even in seawater.

The band-shaped sealing layer has a coating width of 5.0 to 30.
mm, preferably about 10-20 mm, (maximum) layer thickness about 0.5-3.05 mm, preferably 1.5-3.0 mm.
mm is generally appropriate.

It is effective to apply a heavy anticorrosion paint to the edge portion before providing the band-shaped sealing layer.

The heavy-duty anticorrosive paint is defined as the water resistance, weather resistance,
It has excellent adhesion and is used for painting steel structures in harsh corrosive environments such as the marine environment. For example, tar epoxy resin paint, long-oil phthalic acid paint, chlorinated rubber paint, urethane paint, epoxy paint, etc. It is. The width of application of the heavy anticorrosion paint should cover at least the exposed portion of the adhesive layer, and the thickness of the application is suitably about 10 to 500 μm in terms of dry thickness. When a moisture-curable urethane resin is used for the belt-shaped sealing layer, its sealing properties and long-term adhesion are good, so that it is not necessary to provide a heavy-duty anticorrosion paint film. However, by providing such a film, these can be further improved.

When the heavy duty anticorrosion coating has a modified polyolefin layer as an adhesive layer and a polyolefin layer as an anticorrosion layer, the modified polyolefin layer is exposed outside the polyolefin layer to expose the modified polyolefin layer. It is possible to improve the long-term adhesion of the belt-shaped sealing layer (when a heavy corrosion protection paint film is provided, the heavy corrosion protection paint film). The protrusion width may be about 2.0 to 15 mm, preferably about 2.5 to 10 mm. As a method of projecting the modified polyolefin layer to the outside from the polyolefin layer, each layer may be provided in such a manner in advance, but even if the edges of both layers are initially coincident, from the polyolefin layer side after applying the heavy duty anticorrosion coating. It may be cooled. Then, since the polyolefin layer shrinks first, a step is formed between the two layers after cooling, and the modified polyolefin layer is exposed at the edge.

Next, a method for producing a heavy-corrosion-coated steel sheet pile according to the present invention will be described. The scale is completely removed by blasting, and a chemical conversion treatment such as a chromate treatment is performed. Further, the primer coating is applied by a spray coating method or another method, and cured by standing or heating to form a primer layer.

The steel sheet pile that has been subjected to the blasting, chemical conversion treatment, and primer treatment such as primer coating is heated by a heating device such as a heating furnace. The heating temperature is a temperature required for fusing the polyolefin sheet, and is therefore a temperature higher than or equal to the melting point of the modified polyolefin layer, preferably about 10 to 100 ° C. higher than the melting point, and usually about 80 to 200 ° C.

A heated steel sheet pile is coated with a corrosion-resistant polyolefin sheet via a modified polyolefin layer. As this coating method, it is preferable that a modified polyolefin layer and an anticorrosion polyolefin layer are integrated to form a molded polyolefin sheet, and the integrated sheet is supplied to the steel sheet pile so that the modified polyolefin layer side contacts the steel sheet pile. . However, it is not always necessary to be integrated, and only the modified polyolefin layer may be formed in advance on a steel sheet pile that has been subjected to base treatment, and a sheet made of only the anticorrosive polyolefin layer may be adhered thereon. In that case, the modified polyolefin layer is melt-extruded coating, powder coating,
What is necessary is just to form by a fluid immersion method, thermal spraying, sheet sticking, etc. In order to thermally bond the anticorrosion polyolefin sheet, the modified polyolefin layer needs to be at least in a molten state.

The sheet supplied onto the steel sheet pile is adhered by pressing the sheet against the steel sheet pile with a pressing device such as a roll. In this case, it is preferable to sequentially press the steel sheet pile from the central portion to the curved surface portion and then to the peripheral portion in order to prevent air bubbles and the like from being mixed into the sheet and to efficiently attach the sheet.

After the fusion, the excess length of the sheet is trimmed, and the steel sheet pile to which the sheet is adhered is cooled. In the present invention, first, cooling from the polyolefin side is preferable from the viewpoint of reducing residual stress. Cooling is performed by water cooling, air cooling, or other refrigerants. The most efficient way is to spray water from the polyolefin side to cool. This cooling is preferably performed at least until the modified polyolefin layer as the adhesive layer is solidified from the viewpoint of the residual stress reduction effect. Thereafter, even if cooling is performed from both the polyolefin side and the steel material side, the effect of reducing the residual stress does not change, and the cooling time can be shortened.

When a urethane elastomer layer is used for the anticorrosion layer, it may be applied by a known method and left to stand or heated for curing.

When a heavy anticorrosion paint film is provided, it is first applied and formed, and after touch hardening, the moisture-curable resin composition of the present invention, preferably a moisture-curable urethane resin composition, is applied to all the edges of the sheet. It is preferable to apply over the entire surface and seal the end. After the application, it is cured by moisture, so it may be left as it is.

As shown in FIG. 1, the shape of the end seal is preferably applied so as to fill the gap between the end and the steel material and not to protrude much from the sheet plane.

[0046]

Embodiments of the present invention will be described below. U-shaped steel sheet pile (effective width 500 mm, height 225 mm, thickness 24.
3, the surface of the concave surface having a length of 6 m) is subjected to sand blasting until SIS Sa2 1/2 is reached, and a chromating agent is applied and baked on the surface in contact with the sea at the time of use, and the total chromium adhesion amount is 500 mg / m ^2. Was formed. After curing the unpainted part, an epoxy-based primer was spray-coated on the surface so as to have a thickness of 40 μm, and was cured by heating.

Thereafter, the steel sheet pile was heated to 140 ° C. in a heating furnace, and a sheet formed by integrally forming a modified polyethylene layer having a thickness of 0.5 mm and a corrosion-resistant polyethylene layer having a thickness of 2.0 mm on the steel sheet pile in a high temperature state. Was placed and pressed to fuse. The modified polyethylene is a maleic anhydride-modified polyethylene. The density of the anticorrosion polyethylene used is 0.945 g / c.
m ³ , MI 0.25 g / 10 min, Vicat softening point of 118 ° C., and modified polyethylene having a Vicat softening point of 64 ° C.

After the sheet was attached, water was sprayed from the polyethylene side and cooled to room temperature to expose the modified polyethylene layer to the anticorrosion polyethylene layer by about 5 mm to 10 mm. As a comparative example, water was sprayed from the steel material side, and a steel sheet pile having almost no exposed portion was also prepared.

Thereafter, a heavy anticorrosive paint film is formed on the entire side edge portion of the sheet to a thickness of about 50 to 100 μm, and the end portion is sealed with a moisture-curable urethane resin composition through the heavy anticorrosive paint film. Thus, a heavy-duty corrosion-coated steel sheet pile of the present invention was produced. Other end sealing materials were also used as comparative examples.

The following evaluation was performed on this steel sheet pile. (1) Hot salt water immersion test The obtained steel sheet pile was cut into a suitable size, and was cut at 50 ° C and 3%
Immersion in salt water for a long period of time, the adhesion of the coating after immersion is 90 °
It was evaluated by the peel strength method (JIS G 3469). In addition, the coating end of the end sealing portion was forcibly peeled off, and deterioration conditions such as rust and exposure of the iron base at the peeling portion were investigated. (2) Salt spray test The obtained steel sheet pile was cut into an appropriate size, and JIS K5
A salt spray test specified in No. 400 was carried out, and the progress of rust from the end was investigated.

[0051]

[Table 1]

[0052]

[Table 2]

From the results of this accelerated test, it was possible to suppress the deterioration from the end in the warm salt water immersion test and the salt spray test by using the moisture-curable urethane resin composition as the end seal. In addition, by performing the sealing of the end portion through the heavy anticorrosion paint film, the deterioration from the end portion can be further prevented. Further, by exposing the modified polyethylene to the anticorrosion polyethylene, an effect of preventing the end seal material from falling off was observed.

As described above, the heavy duty anti-corrosion coated steel sheet pile produced by the method of the present invention has an excellent edge sealing effect,
It was found that it exhibited extremely excellent adhesion even in various accelerated tests and long-term exposure in the sea.

[0055]

As described above, the heavy-corrosion-coated steel sheet pile of the present invention exhibits extremely excellent long-term adhesion in an acceleration test and an exposure test in a marine environment. As a result, the long-term service life of the coated steel sheet pile can be significantly extended, the maintenance cost of the port facility can be reduced, and the loss of repair costs due to peeling can be prevented. Absent.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (an enlarged view of a side end portion) of an example of a heavy-corrosion-coated steel sheet pile of the present invention.

FIG. 2 is a cross-sectional view of an edge portion of a heavy-corrosion-coated steel sheet pile according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 steel sheet pile 2 ground treatment layer 3 modified polyethylene layer 4 anticorrosion polyethylene layer 5 edge seal layer 6 heavy anticorrosion paint film

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Mitsugu Fuzen 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (56) References JP-A 8-176661 (JP, A) 7-2397 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 15/08

Claims (3)

(57) [Claims] 1. A steel sheet pile provided with a heavy corrosion protection coating, wherein a belt-shaped sealing layer made of a moisture-curable urethane resin is provided at an edge portion of the heavy corrosion protection coating. Sheet pile 2. A steel sheet pile provided with a heavy-duty anticorrosion coating, wherein a band-shaped sealing layer is provided at an edge portion of the heavy-duty anticorrosion coating via a heavy-duty anticorrosion paint film. A heavy-duty coated steel sheet pile characterized by being provided so as to cover an exposed part of an adhesive layer for bonding the heavy duty corrosion-resistant coating to the steel sheet pile. 3. A heavy-duty anticorrosion coating comprising a polyolefin layer and a modified polyolefin layer, and thermally bonding the polyolefin layer to a steel sheet pile in a molten state of the modified polyolefin layer.
A method for manufacturing a heavy-duty corrosion-resistant coated steel sheet pile, comprising: first contracting a polyolefin layer in a cooling process so that an edge of a modified polyolefin layer projects outside the polyolefin layer; and providing a band-shaped sealing layer at the edge.