JPH05247959A - Two-layered color anticorrosive covered steel tubular pile - Google Patents

Abstract

PURPOSE:To raise the colorfulness of a steel tubular pile by a method in which the surface of a steel tube subjected to a base treatment is laminated with a colored polyolefin layer as anticorrosive layer through a modified polyolefin adhesive layer, and the outer surface of the polyolefin layer is subjected to a reforming treatment and laminated with a color paint. CONSTITUTION:The outer surface of a steel tube 1 is subjected to a blasting treatment to remove rust and covered with a chromate film 2 and an epoxy primer layer in order for base treatments. The surface of the films by the base treatments is subjected to a surface reforming treatment containing four components, a specific hindered amine UV stabilizer, a benzotriazole UV absorbent, a phenolic antioxidant, and a colorant, for preventing the surface deterioration by UV and lowering of the bonding strength of the paint films by water. The surface is further covered with a color polyolefin layer 5 treated by flame in such a way as to keep oxygen concentration at 10% or more and various colored paints such as fluororesin paint and others in order. The colorfulness of the steel tube 1 can thus be raised.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy-duty anticorrosion coated steel pipe pile for use in steel structures used at coasts, rivers, harbors, etc.
More specifically, by laminating a colored paint on the colored polyolefin coating of various colors on the outer surface of the heavy anticorrosion coating,
The present invention relates to a heavy-duty anticorrosion coated steel pipe pile having extremely excellent color properties and excellent aesthetics, and having excellent photodeterioration prevention between the colored coating film and the heavy anticorrosion coating and excellent water-resistant adhesion.

[0002]

2. Description of the Related Art For coating a conventional polyolefin-coated steel material, for example, a polyolefin-coated steel pipe pile, black polyethylene having excellent weather resistance and corrosion resistance is used. However, due to the recent increasing market needs for aesthetic landscapes of steel structures such as rivers and harbors, it has been proposed that heavy-duty anti-corrosion coated steel pipe piles that are colored in various colors, are in harmony with the environment, and have excellent weather resistance. Development is desired. To meet such needs, for example, as shown in Japanese Patent Application No. 02-239271 in FIG. 3, a fluorine-based paint coating film having various colors is formed on the surface of a black polyolefin-coated steel material whose outer surface is subjected to corona discharge treatment. There is a heavy anticorrosion coated steel material that is sequentially laminated. In the figure, 7 is a steel pipe, 8 is a chromate treatment agent coating layer, 9
Is an epoxy primer layer, 10 is a modified polyolefin adhesive layer, 11 contains 0.05 to 5.0% antioxidant,
In addition, the surface has a "wetting index (surface tension)" of 36 dyne.
/ Cm indicates a colored polyolefin that has been subjected to corona discharge treatment, 12 indicates a urethane primer layer, and 13 indicates a colored fluorine coating layer.

[0003]

In the polyolefin generally used for heavy-duty anticorrosion coated steel materials, since carbon black having excellent weather resistance is used, the polyolefin becomes black, and when coated with a colored paint, light is not emitted. There is a problem in that excellent texture, depth of color, and chromaticity cannot be realized if the material penetrates the paint film. Further, in the case of the conventional polyolefin containing only the antioxidant and subjected to the surface modification treatment, in the state where sunlight irradiation in the tidal part and immersion in water are repeated, the photo-deterioration of the surface of the polyolefin coating and the polyolefin and the paint Since the adhesive deterioration due to the invasion of water into the adhesive interface cannot be sufficiently suppressed, there is a problem that the adhesiveness of the paint is lowered and the paint film of the paint is easily peeled off.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a polyolefin coating under a paint film is colored with a coloring pigment in the same color as the paint or in a different color. Excellent color is obtained, and further,
It was found that by adding an additive, good paint adhesion in the tidal zone can be obtained. As a result, four components of a specific hindered amine-based UV stabilizer, a benzotriazole-based UV absorber, a phenol-based antioxidant, and a coloring pigment, which are adhered to each other through a modified polyolefin adhesive layer, are applied to the outer surface of a steel pipe that has been subjected to a base treatment. The surface of the colored polyolefin layer containing and subjecting the surface to flame treatment or corona discharge treatment so that the oxygen concentration is 10% or more, has a fluorine-based paint of various colors, an acrylic-silicone-based paint, an acrylic-urethane-based paint. The inventors have found that the above-mentioned problems can be solved by sequentially laminating colored paint coating films such as paints, and have reached the present invention.

That is, according to the present invention, as shown in FIG.
After rust removal such as blast treatment on the outer surface of the, the chromate film 2 and the epoxy primer layer 3 are sequentially laminated and subjected to a base treatment, and a specific hindered amine-based ultraviolet stabilizer is added to the outermost layer through the modified polyolefin adhesive layer 4. A colored polyolefin layer 5 containing four components of a benzotriazole-based ultraviolet absorber, a phenol-based antioxidant, and a coloring pigment, and the surface of which is subjected to flame treatment or corona discharge treatment so that the oxygen concentration is 10% or more. A two-layer colored heavy-corrosion-proof coated steel pipe pile in which colored paint coating films 6 of various colors such as a fluorine-based paint, an acrylic-silicone-based paint, and an acrylic-urethane-based paint are sequentially laminated.

The present invention will be described in detail below.

The steel pipe used in the present invention is a steel pipe made of alloy steel such as carbon steel and stainless steel. Further, for the purpose of improving the corrosion resistance of the steel pipe, the outer surface and the inner surface of the steel pipe are plated with zinc, aluminum, nickel or the like, zinc-iron, zinc-
It is possible to use alloy plating of aluminum, zinc-nickel-cobalt or the like, or plating or alloy plating on which dispersion plating in which inorganic fine particles such as silica or titanium oxide are dispersed is applied.

In the case of producing the double-layered colored heavy-corrosion-proof steel pipe pile of the present invention, the outer surface of the steel pipe is blasted by grid blasting, sand blasting or the like to remove rust, and then a chromate treatment agent is applied and dried, and then the surface is applied. An epoxy primer is applied, heated and cured to perform a surface treatment, and immediately, a modified polyolefin adhesive obtained by modifying a polyolefin with maleic anhydride or the like is electrostatically powder-coated and melted, and the colored polyolefin of the present invention is applied to the surface of the modified polyolefin adhesive. Is subjected to extrusion coating using a T die or a round die, or the adhesive and the colored polyolefin layer are simultaneously extrusion coated using a two-layer extruder, followed by cooling with water. The surface is modified by flame or corona discharge treatment, and a colored paint is applied to produce the double-layer colored heavy-corrosion-coated steel pipe pile of the present invention. From the skeleton of the present invention, it is sufficient that the outer surface of the coated steel pipe pile is firmly laminated and coated with a colored polyolefin and a colored coating layer, and a chromate treatment agent, an epoxy primer, a phosphate treatment, which is conventionally known as a base treatment, A silane coupling agent or the like is used alone, or a combination of these base treatments is used.

As the polyolefin used for forming the modified polyolefin adhesive layer and the colored polyolefin layer of the present invention, polyethylene, polybutene, or ethylene and propylene, 1-butene, 1-pentene, 4-methyl-
A copolymer with an α-olefin such as 1-pentene, 1-hexene or 1-octene is used.

As the modified polyolefin adhesive, a modified polyolefin obtained by modifying a polyolefin with an acid anhydride such as maleic anhydride, a modified polyolefin prepared by adding an elastomer such as ethylene-propylene rubber to a polyolefin with an acid anhydride, or Adhesives obtained by diluting these modified polyolefins with polyolefins are used, but polyolefin-based adhesives other than these can also be used as long as strong adhesion is possible.

The colored polyolefin layer has a specific content in order to prevent the deterioration of the surface layer due to the surface modification treatment, the deterioration of the surface layer due to the ultraviolet rays passing through the coating film, and the decrease in the adhesive force of the coating film due to water. Four components of a hindered amine-based UV stabilizer, a benzotriazole-based UV absorber, a phenolic antioxidant, and a coloring pigment are added as essential components.

As the hindered amine-based UV stabilizer added to the colored polyolefin layer, poly [{6- (1,
1,3,3-Tetramethylbutyl) imino-1,3,5
-Triazine-2,4-diyl} {(2,2,6,6-
Tetramethyl-4-piperidyl) imino} hexanemethylene {(2,2,6,6-tetramethyl-4-pipedyl) imino}] (see Chemical formula 1) or N, N′-bis (3
-Aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3
0.2-2.0w of 5-triazine condensate (see Chemical formula 2)
t% and bis- [2,2,6,6-tetramethyl-4-
Piperidinyl] sebacate (see Chemical Formula 3) 0.1 to 0.
The mixed addition in the proportion of 6 wt% is the most effective.

As the benzotriazole type ultraviolet absorber, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole (see Chemical formula 4) or 2- (3,5- Di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole
0.1 to 1.0 wt% of 2- (3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole (see Chemical Formula 6) is used.

As the phenolic antioxidant, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (see Chemical formula 7) or octadecyl-3- (3 , 5-di-t-
Butyl-4-hydroxyphenyl) propionate (see Chemical formula 8), or N, N'-hexamethylenebis (3,5
-Di-t-butyl-4-hydroxy-hydrocinnamamide) (see Chemical formula 9), or 1,3,5-trimethyl-2,
0.01% of 4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene (see Chemical formula 10) is used.
Add 1.0 wt% and use.

The structures of the aforementioned hindered amine UV stabilizers (Chemical formulas 1 to 3), benzotriazole UV absorbers (Chemical formulas 4 to 6), and phenolic antioxidants (Chemical formulas 7 to 10) are shown below.

[0016]

[Chemical 1]

[0017]

[Chemical 2]

[0018]

[Chemical 3]

[0019]

[Chemical 4]

[0020]

[Chemical 5]

[0021]

[Chemical 6]

[0022]

[Chemical 7]

[0023]

[Chemical 8]

[0024]

[Chemical 9]

[0025]

[Chemical 10]

As the coloring pigment, generally commercially available iron oxides such as titanium oxide, titanium yellow and iron black, lead oxides such as yellow lead, metal oxides such as cobalt blue and cobalt green, and inorganic pigments such as dark blue and cadmium. , Phthalocyanine Green, Phythalocyanine Blue, Quinacridone Red, Perylene Red, Perinone Orange, Isoindolinone Yellow and other organic pigments, and carbon black are used, and one or more of these pigments are mixed and toned. 0.2 to 20.0 wt% is added.

When one of these components is lacking, the surface layer is deteriorated and the adhesion with the paint is lowered under the condition that the irradiation with ultraviolet rays for a long period of time is combined with submersion. Further, when the amount exceeds the above range, the bleed-out of the additive becomes remarkable, so that the treatment effect when the surface modification is performed tends to be insufficient.

Next, the surface modification treatment applied to the surface of the colored polyolefin coating will be described. Since the colored polyolefin has almost no oxidation-inducing group which is a polar group on the surface layer (about 5% within several nm of the surface layer), it does not adhere even if a colored coating material is applied. Therefore, it is necessary to modify the surface to introduce a polar group. As the surface modification treatment, it is necessary to use flame treatment or corona discharge treatment to introduce 10% or more of oxygen into several nm of the surface layer of the polyolefin so as to have adhesiveness with the colored coating material. The introduction amount of the polar group on the surface is simply quantified using an analysis method such as ESCA. Further, the surface modification treatment may use another treatment method as long as sufficient polar groups can be introduced into the surface. When the introduction of the surface polar group is insufficient, the adhesion between the polyolefin coating and the colored paint coating of various colors is reduced after the practical use test in the tidal zone, and blisters occur in the colored paint coating.

Next, the paint used in the present invention will be described. As the paint, from the viewpoint of weather resistance, commercially available acrylic-urethane-based paints such as NY Porin K of various colors manufactured by Shinto Paint Co., V top # 100 of various colors manufactured by Dainippon Paint Co., Ltd., Chinese paints General-purpose acrylic-silicone paints such as silica racks of various colors manufactured by Shinto Paint Co., Ltd., various colors of Ceraforte manufactured by Shinto Paint Co., Ltd., various colors of Duflon manufactured by Nippon Paint Co., Ltd., and V of various colors manufactured by Shinto Paint Co., Ltd. It is desirable to use a general commercially available fluorine-based paint such as CFC.

[0030]

The two-layer colored heavy anticorrosion coated steel pipe pile of the present invention comprises:
As shown in FIG. 1, the chromate treatment 2,
4 components of specific hindered amine UV stabilizer, benzotriazole UV absorber, phenolic antioxidant, and color pigment, which are coated with primer 3 and subjected to a base treatment and adhered via modified polyolefin adhesive layer 4, are essential components , And the surface of the colored polyolefin layer 5 which has been treated by a surface modification method such as flame treatment or corona discharge treatment so that the surface has an oxygen concentration of 10% or more. It is characterized in that colored paint coating films 6 such as acrylic-silicone paint and acrylic-urethane paint are sequentially laminated.

The chromate treatment layer 2 and the epoxy primer layer 3 which are the base treatment maintain a sufficient adhesive force between the modified polyolefin layer adhesive layer 4 on the upper side and the steel material even in a long-term water contact environment, and the steel material. It is necessary to prevent the peeling of the coating. The chromate film 2 has a good adhesion amount of 50 to 1000 mg / m ^{2 in} terms of the total chromium adhesion amount, and the epoxy primer film 3 has a good film thickness of 10 to 150 μm. Since the colored polyolefin layer 5 has no adhesiveness, the modified polyolefin adhesive layer 4 obtained by modifying polyolefin to have adhesiveness is required. The colored polyolefin layer 5 is a specific hindered amine-based ultraviolet stabilizer,
By containing 4 components of benzotriazole type ultraviolet absorber, phenolic antioxidant, and color pigment as essential components, excellent color property when coating the surface and maintenance of coating adhesion by preventing surface deterioration A film thickness of about 1 to 8 mm is suitable because of its function and anticorrosion performance and coverage.
The surface modification applied to the surface of the colored polyolefin 5 is flame,
It is necessary to treat the surface so as to have an oxygen concentration of 10% or more by applying a treatment such as corona so that the surface has adhesiveness. The colored paint coating film 6 is necessary for providing excellent color and long-term weather resistance to the outermost layer of the steel pipe pile, and is applied with a film thickness of 10 to 100 μm. When particularly excellent chromaticity is required, good chromaticity can be obtained by adjusting the pigment concentration in the paint so as to form a translucent film with the film thickness after coating.

[0032]

[Example] Outer diameter 200A x length 5000mm x wall thickness 3.
The outer surface of a 2 mm steel pipe is grid-blasted to remove rust, and the chromate treatment agent has a total chromium adhesion of 500 mg /
It was applied so as to be m ² , and heated at 160 ° C. and baked. While transferring the chromate-treated steel pipe on the V roll, an epoxy primer film having a thickness of 50 μm was formed on the surface thereof.
Spray coating so that
It was heated to ℃ and cured. Then, a maleic anhydride-modified polyethylene adhesive was applied to the surface with a two-layer circular die.
A colored polyolefin containing four components of a hindered amine-based ultraviolet stabilizer, a benzotriazole-based ultraviolet absorber, a phenol-based antioxidant, and a coloring pigment was extrusion-coated to a thickness of 0 to 600 μm to a thickness of 2 mm and water-cooled. After subjecting the surface of the colored polyolefin on the outer surface of the steel pipe to flame treatment or corona discharge treatment, an acrylic-urethane coating (Dainippon Paint), an acrylic-silicon coating (Shinto Paint), Two-layer colored heavy-corrosion protection steel pipe pile 1 according to the present invention by spray-coating one of the fluorine-based paints (Nippon Paint) to a film thickness of 30 μm.
~ 24 was obtained. The surface of the colored polyolefin coating after surface modification is electron spectrosc manufactured by Shimadzu.
It was confirmed that the oxygen concentration was 10% or higher by elemental analysis of the surface layer portion using an opay for chemical analysis device.

[0033]

[Comparative Examples 1 and 2] The outer surface of a steel pipe having an outer diameter of 200 A, a length of 5000 mm, and a wall thickness of 3.2 mm is grid-blasted to remove rust, and the chromate treatment agent has a total chromium deposition amount of 500 m.
It was applied so as to be g / m ² and heated to 160 ° C. for baking. While transferring the chromate-treated steel pipe on a V roll, an epoxy primer film having a thickness of 50 μm was formed on the surface of the pipe.
m by spray painting and 20 by high frequency induction heating
It was heated to 0 ° C. and cured. Then, a maleic anhydride-modified polyethylene adhesive was applied to the surface thereof with a two-layer circular die to a thickness of 400 to 600 μm, and an antioxidant of 0.05 to
2% of colored low density polyethylene with a film thickness of 2 mm containing 5.0%
It was extrusion coated to a thickness of mm and water cooled. After applying a flame treatment or a corona discharge treatment to the surface of the colored polyolefin on the outer surface of the steel pipe, a fluorine-based paint (Nippon Paint) is spray-coated to a film thickness of 30 μm. Comparative colored heavy corrosion-resistant steel pipe piles 1 and 2 corresponding to 02-221715 were obtained. Electron beam crosslinked black low density polyethylene coated surface after surface modification is JISK676
The "wetting index (surface tension)" in the "wetting test method for polyethylene and polypropylene films" specified in 8 is 4
It was 0 dyne / cm.

[0034]

[Comparative Examples 3 to 18] Outer diameter 200 A x length 5000 mm x
The outer surface of a steel pipe with a wall thickness of 3.2 mm is grid blasted to remove rust, and the chromate treatment agent has a total chromium adhesion of 500
It was applied so that the amount would be mg / m ² and heated to 160 ° C. and baked. While transferring the chromate-treated steel pipe on a V roll, an epoxy primer film having a thickness of 50 was formed on the surface thereof.
Spray paint to a size of μm, and use high frequency induction heating to 2
It was heated to 00 ° C. and cured. Then, a maleic anhydride-modified polyethylene adhesive having a thickness of 400 to 600 μm was formed on the surface by a two-layer circular die, and four components of a hindered amine ultraviolet stabilizer, a benzotriazole ultraviolet absorber, a phenolic antioxidant, and a color pigment were added. The adjusted colored polyolefin was extrusion-coated to a thickness of 2 mm and cooled with water. After subjecting the surface of the colored polyolefin on the outer surface of the steel pipe to a flame treatment or a corona discharge treatment for modification, an acrylic-urethane paint (Dainippon paint), an acrylic-silicon paint (Shinto paint), Spray-paint one of the fluorine-based paints (Nippon Paint) to a film thickness of 30 μm for comparative coloring.
I got 18.

Tables 1 to 3 show the abbreviations of hindered amine ultraviolet stabilizers, benzotriazole ultraviolet absorbers, and phenolic antioxidants added to the colored polyolefins in Examples and Comparative Examples.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

The four components of the hindered amine-based UV stabilizer, benzotriazole-based UV absorber, phenolic antioxidant, and color pigment added to the colored polyolefins in Examples and Comparative Examples, the surface modification method, and the color paint are shown in the table below. 4-8.

The double-layered colored heavy-corrosion coated steel pipe piles 1 to 24 according to the present invention and the comparative heavy-duty anti-corrosion coated steel pipe pile 1 obtained as described above
After production of ~ 18, by visual inspection of 50 subjects, 10 points were shown in which the paint of the same color (blue) was applied on the colored polyolefin (blue), and the state was in a very excellent color. Relative evaluation of chromaticity was performed by setting 0 as a state having almost no sexuality. In addition, as a practical use test of the tidal zone, the manufactured coated steel pipe pile is cut and processed, and 70 mm width x 1
50 mm long x 3.2 mm thick cut plate, and a carbon arc lamp type sunshine weatherometer [black panel temperature: 63 ° C, relative humidity: 50%] was used to irradiate these cut plates with ultraviolet rays for 1000 hours and 60 Six cycles of tests were carried out by combining immersion in warm water of ℃ for 1000 hours, and after completion, the occurrence of blisters in the colored paint coating film was observed, and the adhesion test between the colored paint coating film and the colored polyolefin coating was conducted. Test: In accordance with JIS K5400, the adhesive strength is displayed as an evaluation of 0 to 10 points (maximum 10 points) "
Was done. The results are shown in Tables 4-8. As is clear from the results in the table, the two-layer colored heavy anticorrosion coated steel pipe pile according to the present invention is excellent in color development of the paint as compared with the conventional heavy anticorrosion coated steel pipe pile, and has excellent colorability, and a tidal zone actual use test. After that, the blister of the colored paint coating film did not occur, and the adhesion between the colored paint coating film and the colored polyolefin coating was sufficiently high. On the other hand, when the black polyolefin coatings of Comparative Examples 1 and 2 were used, the color of the paint was poor, and the paint adhesion after the actual use test in the tidal range was also reduced in the state where only the additive was added as the antioxidant. Further, when even one of the four components added to the colored polyolefins of Comparative Examples 3 to 6 was missing, when the surface modification of Comparative Example 7 was not performed, the additive component range and surface modification of Comparative Examples 8 to 16 were performed. When the treatment range is exceeded, Comparative Examples 17 to 1
When the other additive of No. 8 is used, the adhesive strength after the practical test of tidal range is lowered.

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

[0044]

[Table 7]

[0045]

[Table 8]

[0046]

As is apparent from the above examples, the specific hindered amine ultraviolet stabilizer and benzotriazole ultraviolet absorber adhered to the outer surface of the steel pipe subjected to the surface treatment through the modified polyolefin adhesive layer. , A phenolic antioxidant, and a coloring pigment, and the surface of the colored polyolefin layer, which has been subjected to flame treatment or corona discharge treatment so that the surface has an oxygen concentration of 10% or more, has various colors of fluorine. Coated steel pipe piles with colored polyolefins in which colored paint coatings such as acrylic-based paints, acrylic-silicone-based paints, acrylic-urethane-based paints, etc. are sequentially laminated have superior color properties compared to conventional heavy-corrosion-coated steel pipe piles. In addition, since there is little deterioration of the surface modification area, various colors such as fluorine-based paint, acrylic-silicone paint, acrylic-urethane-based paint, etc. Water-resistant adhesion between the colored polyolefin-coated is excellent.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a two-layer colored heavy anticorrosion coated steel pipe pile in which the outer surface of the steel pipe pile is coated with the present invention.

FIG. 2 is a partial cross-sectional view of a conventional heavy anticorrosion coated steel material.

[Explanation of symbols]

1 ... Steel pipe pile 2 ... Chromate treatment agent coating layer 3 ... Epoxy primer layer 4 ... Modified polyolefin adhesive layer 5 ... Specific hindered amine-based UV stabilizer, benzotriazole-based UV absorber, phenol-based antioxidant,
It contains four components of a coloring pigment, and the surface has an oxygen concentration of 10
% Colored polyolefin with surface modification such as flame treatment so that the content is at least 6% ... Fluorine-based paint of various colors, acrylic-silicone paint, acrylic-urethane-based paint, etc. Colored paint layer 7 ... Steel pipe 8 ... Chromate treatment Agent coating layer 9 ... Epoxy primer layer 10 ... Modified polyolefin adhesive layer 11 ... Contains 0.05 to 5.0% antioxidant, and the surface has a "wetting index (surface tension)" of 36 dyne / cm or more. Polyolefin 12 ... Urethane Primer Layer 13 ... Colored Fluorine Paint Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location E02D 5/04 9231-2D

Claims (3)

[Claims] 1. A steel pipe that has been subjected to a base treatment is laminated with a colored polyolefin layer containing the following components (1) to (5) as essential components as an anticorrosion layer through a modified polyolefin adhesive, and the outer surface is modified. , Heavy duty anticorrosion coated steel pipe pile characterized by sequentially laminating any one of various colored paints such as fluorine-based paints of various colors, acrylic-silicone-based paints, acrylic-urethane-based paints, hindered amine-based UV stabilizers benzotriazole-based UV stabilizers Absorber Phenolic antioxidant Coloring pigment 2. A hindered amine antioxidant is poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl}.
{(2,2,6,6-tetramethyl-4-piperidyl)
Imino} hexamethylene {(2,2,6,6-tetramethyl-4-pipedyl) imino}] or N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-] N- (1,2,2,6,6-pentamethyl-4piperidyl) amino] -6-chloro-1,3
0.2-2.0 wt% of 5-triazine condensate, bis-
[2,2,6,6-Tetramethyl-4-piperidinyl]
It is a mixed addition of sebacate of 0.1 to 0.6 wt%, and the benzotriazole-based ultraviolet absorber is 2- (3
-T-butyl-5-methyl-2-hydroxyphenyl)
-5-chlorobenzotriazole, or (2- (3,5
-Di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, or 2- (3,5-di-t-
Amyl-2-hydroxyphenyl) benzotriazole is 0.1 to 1.0 wt%, phenolic antioxidant is 0.01 to 1.0 wt%, and color pigment is 0.2 to 2
It is 0.0 wt%, The two-layer colored heavy-corrosion protection steel pipe pile of Claim 1 characterized by the above-mentioned. 3. A method for modifying the surface of a colored polyolefin, characterized in that flame treatment or corona discharge treatment is carried out so that the oxygen concentration on the outer surface becomes 10% or more, and the coating films of colored paint are sequentially laminated. The two-layer colored heavy corrosion-resistant coated steel pipe pile according to claim 1.