JP2647316B2 - Colored polyurethane coated steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to steel sheet piles, H-section steels, steel walls for steel walls, steel pipe piles, square steel pipe piles, steel pipe sheet piles, steel sheet and other steel structural members used in the ocean, rivers, ports and the like. The present invention relates to a polyurethane-coated steel material to be used, and more particularly to a colored polyurethane-coated steel material which is colored in various colors and has excellent weather resistance which simultaneously prevents fading due to light, particularly ultraviolet rays.

[0002]

2. Description of the Related Art As a conventional polyurethane-coated steel material, a black polyurethane coating obtained by adding a black pigment such as carbon black having excellent weather resistance to polyurethane proposed in JP-A-57-21463 is used.

[0003] However, with the recent growing market needs for the aesthetics of urban landscapes, rivers, and harbor steel structures, development of polyurethane-coated steel materials that are colored in various colors, are in harmony with the environment, and have excellent anticorrosion properties have been developed. Is desired.

[0004] In order to meet such needs, Japanese Patent Application No. Hei.
No. 99802 is disclosed.

[0005]

However, in such a conventional steel material coated with a colored polyurethane, when the ultraviolet light is applied for a long period of time, the colored polyurethane coating is discolored and discolored, and the appearance is impaired.

There are proposals to add various hindered amine-based weathering agents and the like in order to prevent fading of the surface. However, if these weathering additives are simply added, for example, an outdoor exposure test for about 5 years may cause the surface to be discolored. Fading cannot be prevented. As described above, it was difficult to prevent the surface from fading with the conventional technology.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a black polyurethane layer containing carbon black, Co, Al, Cr, Fe, Ti, Zr, Mn,
The above-described problem is caused by laminating a colored polyurethane layer having a hindered amine-based light stabilizer and a colored pigment composed of an oxide or a composite oxide of one or more elements selected from Sb, Ni and Mg, alone or as a mixture. Can be solved, and the present invention has been achieved.

That is, according to the present invention, as shown in FIGS. 1 to 8, for example, the surface of a steel material 1 such as a steel plate, a steel sheet pile, an H-section steel, a sectional steel wall, a steel pipe pile, a square steel pipe pile and a steel pipe sheet pile is blasted. The scale and the like are removed by a treatment or the like, the urethane primer layer 2 is coated and cured, a base treatment is performed, the black polyurethane layer 3 added with carbon black is painted and cured, and then Co, Al, Cr, Fe, Ti , Zn, Mn, Sb, N
i. A colored polyurethane layer 4 containing a hindered amine-based light stabilizer and a colored pigment composed of a single or mixture of oxides or composite oxides of one or more elements selected from Mg, and cured and laminated. It is a colored polyurethane-coated steel material characterized by the following. Hereinafter, the present invention will be described in detail.

The steel material used in the present invention is a steel plate, a steel sheet pile, an H-section steel, a sectional steel wall for a continuous wall, a steel pipe pile, a square steel pipe pile, and a steel pipe sheet pile made of alloy steel such as carbon steel and stainless steel.

Further, in order to improve the corrosion resistance of the steel material, the surface is plated with zinc, aluminum, chromium, etc.
It is also possible to use an alloy plating of aluminum, zinc-nickel, or the like, or a plating or alloy plating subjected to dispersion plating in which inorganic fine particles such as silica or titanium oxide are dispersed.

When the colored polyurethane-coated steel material of the present invention is manufactured, as a base treatment for the steel material, the surface of the steel material is blasted with grit blast or sand blast to remove rust, and then the urethane primer layer 2 is coated and cured. To perform a base treatment.

As the urethane primer, for example, a mixture obtained by reacting a polyol with a polyisocyanate compound and adding an inorganic pigment to an isocyanate-terminated urethane prepolymer can be used.

In this case, a polyether polyol or a polyolefin polyol is used as the polyol.

As the polyether polyol, propylene glycol, butanediol, neopentyl glycol, hexanediol, glycerin, trimethylolpropane and the like are added with an alkylene oxide such as propylene oxide, ethylene oxide or butylene oxide in the presence of an alkali catalyst or the like. A polyalkylene polyol having two to three active hydrogen groups (hydroxyl groups) in a molecule obtained by weighting is used.

As these polyalkylene polyols, for example, a commercially available hydroxyl value of 50 to 150 mg-K
Polypropylene glycol of about OH / g can be used.

The polyolefin polyol has two to three active hydrogen groups (hydroxyl groups) in a molecule obtained by addition polymerization of a diene compound such as butadiene or isoprene with an alkylene oxide such as ethylene oxide or propylene oxide. A polydiene polyol is used.

These polydiene polyols include:
For example, a commercially available hydroxyl value is 50 to 150 mg-KOH
/ G of polybutadiene polyol or the like can be used.

As the polyisocyanate, a polyisocyanate compound such as crude diphenylmethane diisocyanate (crude MDI) or tolylene diisocyanate (TDI) containing two or more isocyanate groups in a molecule is used.

The above-mentioned polyol and polyisocyanate are subjected to an addition reaction to form an isocyanate-terminated urethane prepolymer. At this time, the ratio of the isocyanate group (—NCO) of the polyisocyanate to the hydroxyl group (OH) of the polyol, that is, NCO / OH is calculated by weight. The reaction is performed so that the ratio is in the range of 1.6 to 3.

If the NCO / OH weight ratio is less than 1.6 or more than 3, the immersion test or the like will cause the black polyurethane layer to peel off, resulting in poor water resistance. In the urethane primer, an inorganic pigment is added to the above isocyanate-terminated urethane prepolymer.

As the inorganic pigment, silicon oxide obtained by pulverizing minerals such as clay and pearlite, aluminum silicate, talc, alumina and calcium carbonate obtained by pulverizing kaolin, kaolin clay and montmorillonite are used.

These inorganic pigments are used in an amount of from 20 to 20 based on 100 parts by weight of the isocyanate-terminated urethane prepolymer.
It is added in a range of 0 parts by weight. If the amount is less than 20 parts by weight or more than 200 parts by weight, the water-resistant adhesiveness will be poor.

As the black polyurethane layer 3, for example, a polyurethane comprising a polyolefin polyol, an aromatic amine polyol, a polyisocyanate and an inorganic pigment can be used, and carbon black is added to the polyurethane.

In this case, the polyolefin polyol has two to three active hydrogen groups (hydroxyl groups) in a molecule obtained by addition polymerization of a diene compound such as butadiene or isoprene with an alkylene oxide such as ethylene oxide or propylene oxide. Use a polydiene polyol.

As the polydiene polyol, for example, Poly bdR-45HT, available from Idemitsu Petrochemical Co., Ltd.
y bd R-45, Poly bd CS-15, Nisso PBG-2000, Nisso PBG-30 manufactured by Nippon Soda Co., Ltd.
A commercially available liquid polybutadiene polyol such as 00 can be used.

As the aromatic amine polyol, bis (2-
Hydroxypropyl) aniline, methylenebis (-O-
An aromatic amine polyol obtained by adding an alkylene oxide such as propylene oxide to an aniline compound such as chloroaniline (MOCA) is used.

These aromatic amine polyols include, for example, polyhardener PA40 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
0, polyhardener PA300, etc. can be used.

These aromatic amine polyols are used in an amount of 30 parts by weight based on 100 parts by weight of the polyolefin polyol.
It is added in the range of １００100 parts by weight.

The amount of the aromatic amine polyol added to the polyolefin polyol is less than 30 parts by weight and
If it exceeds 0 parts by weight, the fading of the upper colored polyurethane layer 4 cannot be prevented.

As the polyisocyanate, 2 in the molecule is used.
An isocyanate compound such as crude diphenylmethane diisocyanate (crude MDI) or tolylene diisocyanate (TDI) containing at least two isocyanate groups is used.

These polyisocyanates have a ratio of the isocyanate group (—NCO) of the polyisocyanate to the hydroxyl group (OH) of the mixture of the above-mentioned polyolefin polyol and aromatic polyol, that is, NCO / OH in a weight ratio of 0.85 to 1. Used for range 5.

If the NCO / OH ratio is less than 0.85 or more than 1.5, the fading of the upper colored polyurethane layer 4 cannot be prevented.

As the inorganic pigment, powders such as silicon oxide obtained by pulverizing minerals such as clay and pearlite, aluminum silicate, talc, alumina and calcium carbonate obtained by pulverizing kaolin, kaolin clay and montmorillonite are used alone or in combination.

The mixing ratio of these inorganic pigments for each type may be arbitrarily selected, but the total amount of the inorganic pigments is in the range of 5 to 200 parts by weight based on 100 parts by weight of the polyolefin polyol.

If the amount of the inorganic pigment is less than 5 parts by weight or more than 200 parts by weight, the discoloration of the upper colored polyurethane layer 4 cannot be prevented.

In order to prevent fading of the upper colored polyurethane layer 4 due to ultraviolet rays, 1 to 30 parts by weight of carbon black is added to the above-mentioned polyolefin polyol.

If the amount of the carbon black is less than 1 part by weight or more than 30 parts by weight, it is impossible to prevent fading of the upper colored polyurethane layer 4.

The colored polyurethane layer 4 is composed of an acrylic polyol, an aliphatic isocyanate-terminated urethane prepolymer and Co, Al, Cr, Fe, Ti, Zn, Mn, Sb, N
i, a coloring pigment comprising an oxide or a composite oxide of one or more elements selected from Mg alone or as a mixture, and a hindered amine light stabilizer.

Examples of the acrylic polyol include methacrylate monomers such as methyl methacrylate and ethyl methacrylate or acrylates such as methyl acrylate and ethyl acrylate and hydroxyl groups such as hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate and hydroxypropyl acrylate. A copolymer obtained by copolymerizing an ethylenically unsaturated monomer with a known method is used.

As these acrylic polyols, commercially available acrylic polyols such as Takelac UA-702, Takelac UA-902 and Takelac UA-905 manufactured by Takeda Pharmaceutical Co., Ltd. can be used.

As the aliphatic isocyanate-terminated urethane prepolymer, a compound obtained by an addition reaction between a polyether polyol and an aliphatic isocyanate is used.

As the polyether polyol, an alkylene oxide such as propylene oxide, ethylene oxide or butylene oxide is added to propylene glycol, butanediol, neopentyl glycol, hexanediol, glycerin, trimethylolpropane or the like in the presence of an alkali catalyst or the like. A polyalkylene polyol having two to three active hydrogen groups (hydroxyl groups) in a molecule obtained by polymerization is used, and hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), or xylylene diisocyanate (XDI) is used. Use is made of an aliphatic isocyanate-terminated urethane prepolymer obtained by the addition reaction of an aliphatic isocyanate such as

Examples of these aliphatic isocyanate-terminated urethane prepolymers include Takenate D-160N manufactured by Takeda Yakuhin Kogyo Co., Ltd. obtained by adding hexamethylene diisocyanate to alkylene polyol, and Takenate D manufactured by Takeda Yakuhin Kogyo Co., Ltd. obtained by adding isophorone diisocyanate.
-140, Takeda D-110N manufactured by Takeda Pharmaceutical Co., to which xylylene diisocyanate is added, and the like.

The acrylic polyol and the aliphatic isocyanate-terminated urethane prepolymer are mixed with NCO / OH
Mix so that the ratio is in the range of 0.5-2.

In order to prevent discoloration due to ultraviolet rays, these mixtures particularly contain Co, Al, Cr, Fe, Ti,
A coloring pigment composed of an oxide or a composite oxide of one or more elements selected from Zn, Mn, Sb, Ni, and Mg, alone or as a mixture, is added.

Co, Al, Cr, Fe, Ti, Zn, M
Color pigments consisting solely or as a mixture of oxides or composite oxides of one or more elements selected from n, Sb, Ni and Mg include, for example, single oxides of Ti (titanium oxide / white), Shepherd Color Company
Single oxide of Co (CONCORD BLUE #)
92 / purple), a single oxide of Mn (MANGANO V
IORET # 11 / purple), composite oxide of Co-Al (ARCTIC BLUE # 3 / blue, ENSIGN)
BLUE # 214 / blue), CO-Cr-Al composite oxide (TOPAZBLUE # 9 / blue, OLYMPIC)
BLUE # 190 / Blue, KINGGFISHER B
LUE # 211 / blue), Fe-Ti composite oxide (R
USSET BROWN # 8 / Brown, Fe-Al-Ti
Composite oxide (GOLDEN BLOWN # 19 / brown), Fe—Zn—Ti composite oxide (AUTUNMN)
BROWN # 156 / brown), Fe-Cr-Zn-Ti
Composite oxide (WALNUBROWN # 10 / brown,
COCOA BROWN # 157 / brown), Fe-Cr
-Mn-Ti composite oxide (CHOCOLATE BR
OWN # 20 / brown), composite oxide of Mn-Cr-Sb-Ti (IRONSTONE BROWN # 39 / brown), composite oxide of Cr-Ni-Cu-Sb-Ti (B
UCKSKINBROWN # 47 / brown), Mn-Sb
-Composite oxide of Ti (URBAN BROWN # 153)
/ Brown, INDIAN BROWN # 2211 / brown),
Ni-Sb-Ti composite oxide (SUNFLOWER
YELLOW # 14 / Yellow, MAPLE YELLOW
# 25 / Yellow, PRIMROSE YELLOW # 19
5 / yellow), Cr-Sb-Ti composite oxide (HONE
Y YELLOW # 29 / Orange, HONEY G
OLD YELLOW # 193 / orange), Ni-
Composite oxide of Sb-Ti (COLONIAL YELL
OW # 182 / Orange, MARIGOLD YEL
LOW # 196 / orange), Ni-Co-Zn-T
i complex oxide (SHAMROCK GREEN # 22
3 / green), Co-Zn-Ti-Cr composite oxide (C
AMOFLAGE GREEN # 179 / green), Ni
-Co-Zn-Sb-Ti composite oxide (JADE G
REEN # 4 / Green, SHERWOOD GREEN #
5 / green), a single-color fired pigment powder such as a composite oxide of Co-Cr-Mg-Al-Zn (TEAL GREEN # 201 / green), or a mixture of these single-color fired pigment powders. .

The type and proportion of the powder to be mixed can be arbitrarily determined from the viewpoint of aesthetics. To prevent fading of the coating, the powder of the single-color fired pigment or the mixture of the single-color fired pigment is used. Is added in the range of 1 to 30 parts by weight based on 100 parts by weight of the acrylic polyol.

If the amount is less than 1 part by weight or more than 30 parts by weight, the discoloration of the coating after the exposure test cannot be prevented.

When an organic pigment is used, discoloration of the coated surface occurs in a long-term outdoor exposure test.

Further, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 8-benzyl-7,
7,9,9-tetramethyl-3-octyl 1,3,8-
A hindered amine light stabilizer such as triazaspiro [4,5] undecane-2,4-dione is added.

As bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, Sanol LS-292 and Sanol LS-765 manufactured by Sankyo Co., Ltd. are used. Methyl-4-piperidyl) sebacate, Sanol LS-770 manufactured by Sankyo,
8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione is Sanol LS- manufactured by Sankyo
1114 etc. can be used.

These hindered amine light stabilizers include:
0.5 to 100 parts by weight of the acrylic polyol
It is added in the range of 10 to 10 parts by weight.

When the amount of the hindered amine-based light stabilizer is less than 0.5 parts by weight or more than 10 parts by weight, the color fading of the colored polyurethane layer 4 after the exposure test cannot be prevented.

Next, the method for producing the colored polyurethane-coated steel material of the present invention will be described by taking steel sheet pile as an example.

Grit blasting is applied to the mountain surface or the valley surface of the steel sheet pile, and a urethane primer is spray-coated and hardened.

Next, a black polyurethane is spray-coated on the surface and cured, and a colored polyurethane is spray-coated on the surface and cured to produce the colored polyurethane-coated steel sheet pile of the present invention shown in FIG. 2 or FIG.

As a method of applying the urethane primer 2, the black polyurethane 3, and the colored polyurethane 4, a conventionally known method such as ironing with a rubber ring or a rubber spatula can be used in addition to spray coating.

The colored polyurethane-coated H-section steel of the present invention shown in FIG. 4 is obtained by subjecting the entire surface of the H-section steel 1 to sandblasting.
The urethane primer 2 is spray-coated and cured.

Then, the surface is spray-coated with black polyurethane 3 and cured, and the surface is further spray-coated with colored polyurethane 4 and cured to obtain the colored polyurethane-coated H-section steel of the present invention.

As shown in FIG. 5, the colored polyurethane-coated steel wall for a continuous wall of the present invention shown in FIG. 5 is obtained by subjecting the entire surface of the steel wall for a continuous wall 1 to sandblast treatment, spray-coating a urethane primer 2 and curing.

Next, the surface of the colored polyurethane 3 is spray-coated and cured, and the surface of the colored polyurethane 4 is spray-coated and cured to obtain the colored polyurethane-coated steel wall for continuous wall according to the present invention.

The colored polyurethane-coated steel pipe pile of the present invention shown in FIG. 6 has a grit blast treatment on the outer surface thereof while rotating the steel pipe 1 in a spiral shape, and is spray-coated with a urethane primer 2 and cured.

Then, black polyurethane 3 is spray-coated on the surface and cured, and then colored polyurethane 4 is spray-coated on the surface and cured to obtain a colored polyurethane-coated steel pipe pile according to the present invention.

In the colored polyurethane-coated square steel pipe pile according to the present invention shown in FIG. 7, the outer surface is subjected to grit blasting while the square steel pipe 1 is transferred and conveyed by a transfer table, and the urethane primer 2 is spray-coated and cured.

Next, black polyurethane 3 is spray-coated on the surface and cured, and then colored polyurethane 4 is spray-coated on the surface and cured to obtain a colored polyurethane-coated steel pipe pile according to the present invention.

In the colored polyurethane-coated steel sheet pile according to the present invention shown in FIG. 8, the outer surface of the steel sheet pile 1 is sandblasted, and the urethane primer 2 is spray-coated and cured.

Next, the surface of the black polyurethane 3 is spray-coated and cured, and the surface of the colored polyurethane 4 is spray-coated and cured to obtain the colored polyurethane-coated steel sheet pile according to the present invention.

The colored polyurethane-coated steel material of the present invention is shown in FIG.
As shown in FIG. 8, the surface of a steel material 1 such as a steel sheet, a steel sheet pile, an H-section steel, a section steel for a continuous wall, a steel pipe pile, a square steel pipe pile, a steel pipe sheet pile, etc., is subjected to blast treatment or the like to remove scale and the like, and a urethane primer The layer 2 is painted and cured to provide a base treatment, the black polyurethane layer 3 to which carbon black is added is painted and cured, and then Co, Al, Cr, Fe, Ti, Z
The colored polyurethane layer 4 containing a hindered amine-based light stabilizer and a color pigment composed of a single or mixture of oxides or composite oxides of one or more elements selected from n, Mn, Sb, Ni, and Mg. This is a colored polyurethane-coated steel material characterized by being hardened and laminated by heating.

The urethane primer layer 2 has a thickness of 20 to 15
0 μm thickness, black polyurethane layer 3 is 0.5 to 15 m
Good results can be obtained if the colored polyurethane layer 4 has a thickness of 0.3 to 10 mm.

Hereinafter, the present invention will be described based on examples.

[0071]

【Example】

[0072]

Embodiment 1

[0073]

Preparation Example of Urethane Primer 1 of the Present Invention First, polypropylene glycol, crude MDI and a solvent were placed in a glass flask and heated at 90 ° C. to react to obtain an isocyanate-terminated urethane prepolymer.

Preparation: polypropylene glycol: 20
0 parts by weight (hydroxyl value: 150 mg-KOH / g, molecular weight: 700) Crude MDI (isocyanate group content: 31%): 14
5 parts by weight

The obtained isocyanate-terminated urethane prepolymer; NCO / OH (weight ratio): 2 Isocyanate group content: 6.3%

To the above-mentioned isocyanate-terminated urethane prepolymer, 20% by weight of a fine clay powder and 20% by weight of a solvent were added as inorganic pigments.
I got

[0077]

Preparation Example of the Black Polyurethane Paint 1 of the Present Invention The following components were blended to obtain the black polyurethane paint 1 of the present invention.

Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd.)
Hydroxyl value: 46.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0079]

[Preparation of Colored Polyurethane Coating 1 of the Present Invention] The following components were blended to prepare a colored polyurethane coating of the present invention.

Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value:
50 mg-KOH / g) Aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5 parts by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.5

[0081]

Preparation Example of Conventional Comparative Colored Polyurethane Paint 1 The following components were blended to obtain a conventional colored polyurethane paint 1.

Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd.)
Hydroxyl value: 46.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Phthalocyanine blue (color: blue): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above paint: 0.85

[0083]

[Production example of coated steel sheet pile] As shown in FIG.
The surface of the mountain of SPIII type × 5 m) was grit blasted to remove rust, and the surface of the urethane primer of the present invention was spray-coated to a thickness of 30 μm and cured to form a urethane primer layer 2. To perform a base treatment.

Next, the above-mentioned black polyurethane paint of the present invention was spray-coated on the surface so as to have a thickness of 2 mm, and was cured to form a black polyurethane layer 3.

Next, the colored polyurethane coating of the present invention is spray-coated on the surface so as to have a thickness of 1 mm, and a colored polyurethane layer 4 is laminated thereon. 1 was obtained.

As a comparative example, a steel sheet pile (FSPIII type ×
5m) is grit blasted to remove rust, and the urethane primer of the present invention is coated on the surface with a thickness of 30 m.
The composition was spray-coated to a thickness of μm and cured to form a urethane primer layer, and a base treatment was performed.

Next, a conventional colored polyurethane paint 1 was spray-coated on the surface so as to have a thickness of 3 mm and cured, and a conventional colored polyurethane layer was laminated thereon. 42 was obtained.

These coated steel sheet piles were cut to a length of 1 m,
Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by performing an exposure test on a river for 7 years.

From the results shown in Table 1, the coated steel sheet pile of the present invention in which the black polyurethane layer and the colored polyurethane layer were laminated was
Compared to a coated steel sheet pile coated with a conventional colored polyurethane layer, there is almost no fading on the surface and excellent weather resistance.

[0090]

Example 2 The following invention of the present invention in which the amount of the aromatic amine polyol compounded in the black polyurethane paint used for forming the black polyurethane layer was changed to 50 parts by weight and 100 parts by weight based on 100 parts by weight of the polybutadiene polyol. Black polyurethane paints 2 and 3 were prepared.

As comparative examples, the following comparative black polyurethane paints 1 and 2 were prepared in which the amount of the aromatic amine polyol was changed to 29 parts by weight and 101 parts by weight.

[0092]

[Black polyurethane paint 2 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 50 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
52.6 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0093]

[Black polyurethane coating material 3 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 100 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420)
mg-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
95.8 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0094]

[Comparative black polyurethane paint 1] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 29 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
34.5 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0095]

[Comparative black polyurethane paint 2] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 101 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420)
mg-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
96.5 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.85

Next, as shown in FIG.
The valley surface of the (III type × 5 m length) 1 is sand-blasted to remove rust, and the urethane primer 1 of the present invention of Example 1 is spray-coated so as to have a thickness of 50 μm and cured to form the urethane primer layer 2. It was formed and subjected to a base treatment.

Next, the above-mentioned black polyurethane paint 2 or 3 of the present invention was spray-coated so as to have a thickness of 2.5 mm, and was cured to form a black polyurethane layer 3.

Further, the colored polyurethane paint 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 1.5 mm, cured and laminated with a colored polyurethane layer 4, and the colored polyurethane-coated steel sheet pile of the present invention was laminated. No. 2 and 3 were produced.

As a comparative example, the above-mentioned comparative black polyurethane paint 1 or 2 was applied instead of the black polyurethane paint of the present invention, and the colored polyurethane-coated steel sheet pile No. 43
And 44 were manufactured.

These coated steel sheet piles were cut to a length of 1 m,
Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by performing an exposure test on a river for 7 years.

From the results shown in Table 1, the colored polyurethane-coated steel sheet pile No. Taking the results of Table 1 (Table 1, 1, Example 1) into consideration, the black polyurethane layer of the present invention contains an aromatic amine polyol and a polyolefin polyol 1
Only in the case where 30 to 100 parts by weight is added to 00 parts by weight, the surface of the colored polyurethane layer after the river exposure test is not discolored and the weather resistance is excellent.

[0102]

Example 3 Polyisocyanate (crude M) blended in a black polyurethane paint used for forming a black polyurethane layer
DI) in an NCO / OH weight ratio of 1.0 and 1.5
The following black polyurethane paints 4 and 5 of the present invention were prepared.

As a comparative example, the amount of the crude MDI was N
The following comparative black polyurethane paints 3 and 4 were prepared by changing the CO / OH weight ratio to 0.7 and 1.6, respectively.

[0104]

[Example of preparation of black polyurethane coating material 4 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
41.7 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 1.0

[0105]

[Example of preparation of black polyurethane paint 5 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
62.7 parts by weight Inorganic pigment (clay fine powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 1.5

[0106]

[Example of preparation of comparative black polyurethane paint 3] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
29.2 parts by weight Inorganic pigment (clay fine powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.7

[0107]

[Comparative Example of Comparative Black Polyurethane Paint 4] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
66.7 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 1.6

Next, as shown in FIG.
(mm × 125 mm, maximum thickness: 9 mm, length 5 m) The surface of 1 was sand-blasted to remove rust, and the urethane primer 1 of the present invention of Example 1 was coated on the surface to a thickness of 40 μm.
Spray paint to make urethane primer layer 2
Was formed, and a base treatment was performed.

Next, the above-mentioned black polyurethane paint 4 or 5 of the present invention was spray-coated on the surface so as to have a thickness of 3 mm and cured to form a black polyurethane layer 3.

Next, the colored polyurethane paint 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 1.5 mm, cured, and a colored polyurethane layer 4 was laminated thereon to form a colored polyurethane coating of the present invention. H-section steel No. 4 and 5 were each manufactured.

As a comparative example, a colored polyurethane-coated H-section steel No. No. 1 was prepared by applying the above comparative black polyurethane paint 3 or 4 instead of the black polyurethane paint of the present invention. 45
And 46 were each manufactured.

These coated H-section steels were cut to a length of 1 m,
Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by performing an exposure test on a river for 7 years.

Taking the results of Table 1 into consideration, the results of the colored polyurethane-coated steel sheet pile 1 of the present invention (Table 1, 1, Example 1) are also considered. Only when the NCO / OH weight ratio is in the range of 0.85 to 1.5 with respect to the mixture of the aromatic amine polyol and the aromatic amine polyol, the colored polyurethane layer surface after the river exposure test is not discolored and the weather resistance is excellent.

[0114]

Example 4 The following black polyurethane of the present invention in which the amount of the inorganic pigment compounded in the black polyurethane paint used for forming the black polyurethane layer was changed to 100 parts by weight and 200 parts by weight with respect to 100 parts by weight of the polyolefin polyol. Paints 6 and 7 were prepared.

As comparative examples, the following comparative black polyurethane paints 5 and 6 were prepared in which the blending amount of the inorganic pigment was changed to 4 parts by weight and 210 parts by weight with respect to 100 parts by weight of the polyolefin polyol.

[0116]

[Example of preparation of black polyurethane paint 6 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (fine clay powder): 100 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 40% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0117]

[Example of preparation of black polyurethane paint 7 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (clay fine powder): 200 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 50% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0118]

[Example of preparation of comparative black polyurethane paint 5] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (fine clay powder): 4 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 50% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0119]

[Comparative Example of Comparative Black Polyurethane Paint 6] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (clay fine powder): 210 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 50% by weight NCO / OH (weight ratio) of the above coating material: 0.85

Next, as shown in FIG. 5, a section steel for connecting walls (total width: 750 mm, beam: 350 mm, flange thickness: 9 m)
m, length 5 m) The surface of 1 is grit blasted to remove rust, and the surface is spray-coated with the urethane primer 1 of the present invention of Example 1 so as to have a thickness of 45 μm and cured to form a urethane primer layer. 1 was formed, and a base treatment was performed.

Next, the above-mentioned black polyurethane paint 6 or 7 of the present invention was spray-coated on the surface so as to have a thickness of 3 mm, and was cured to form a black polyurethane layer 2.

Next, the colored polyurethane coating material 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 2 mm and cured, and a colored polyurethane layer 4 was laminated thereon to form a colored polyurethane coating layer of the present invention. No. of shaped steel for walls 6 and 7
Were each manufactured.

As a comparative example, the colored polyurethane-coated steel wall for a continuous wall No. 5 was prepared by using the above comparative black polyurethane paint 5 or 6 instead of the black polyurethane paint of the present invention. 4
7 and 48 were each manufactured.

Table 1 shows the results of measuring the color difference of the surface of the colored polyurethane layer by cutting the coated steel sections having a length of 1 m and measuring the color polyurethane layer surface for 7 years by performing an exposure test on a river.

From the results shown in Table 1, the colored polyurethane-coated steel sheet pile No. Considering also the results of Table 1 (Table 1, 1, Example 1), the river is only obtained when the inorganic pigment is added to the black polyurethane layer of the present invention in the range of 5 to 200 parts by weight based on 100 parts by weight of the polyolefin polyol. There is no fading on the surface of the colored polyurethane layer after the exposure test, and the weather resistance is excellent.

[0126]

Example 5 The amount of carbon black to be compounded in the black polyurethane paint used for forming the black polyurethane layer was 10 to 100 parts by weight of the polyolefin polyol.
The following black polyurethane paints 8 and 9 of the present invention were prepared by changing the parts by weight to 30 parts by weight.

As comparative examples, comparative black polyurethane paints 7 and 8 were prepared in which the amount of the carbon black was changed to 0 parts by weight and 31 parts by weight with respect to 100 parts by weight of the polyolefin polyol.

[0128]

Preparation Example of Black Polyurethane Paint 8 of the Present Invention The following components were blended to obtain black polyurethane paint 1 of the present invention.

Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd.)
Hydroxyl value: 46.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 10 parts by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above paint: 0.85

[0130]

[Example of preparation of black polyurethane paint 9 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 30 parts by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above paint: 0.85

[0131]

[Comparative example of comparative black polyurethane paint 7] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 0 parts by weight (not added) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.85

[0132]

[Comparative example of comparative black polyurethane paint 8] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
37.9 parts by weight Inorganic pigment (fine clay powder): 5 parts by weight Carbon black (fine powder): 31 parts by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.85

Next, as shown in FIG. 6, a steel pipe pile (SGP
The outer surface of (200A × 5 m length × 6 mm thickness) 1 is grit blasted to remove rust, and the urethane primer 1 of the present invention of Example 1 is spray-coated so as to have a film thickness of 50 μm and the urethane primer layer 2 Was formed and a base treatment was performed.

Next, the above-mentioned black polyurethane paint 8 or 9 of the present invention was spray-coated on the surface so as to have a thickness of 2 mm, and was cured to form a black polyurethane layer 3.

Then, the colored polyurethane coating 1 of the present invention of Example 1 was spray-coated on the surface thereof so as to have a thickness of 1 mm, cured, and the colored polyurethane layer 4 was laminated thereon. No. 8 and 9 were each manufactured.

As a comparative example, the above-mentioned comparative polyurethane paint 7 or 8 was used instead of the black polyurethane paint of the present invention.
Using a colored polyurethane-coated steel pipe pile no. 49 and 50
Were each manufactured.

[0137] These coated steel pipe piles were cut to a length of 1 m,
Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by performing an exposure test on a river for 7 years.

From the results in Table 1, when the results of the colored polyurethane-coated steel sheet pile 1 of the present invention (Table 1, 1, Example 1) are also considered, carbon black is used as the polyolefin polyol in the black polyurethane layer of the present invention. Only when added in the range of 1 to 30 parts by weight with respect to 100 parts by weight, the colored polyurethane layer surface after the river exposure test does not fade and has excellent weather resistance.

[0139]

Example 6 The following black polyurethane coatings 10 and 11 of the present invention were prepared by changing the kind of inorganic pigment to be mixed into the black polyurethane coating used for forming the black polyurethane layer.

[0140]

[Example of preparation of black polyurethane coating material 10 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Polyhardener PA400 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
41.7 parts by weight Inorganic pigment (kaolin clay fine powder): 20 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 1.0

[0141]

[Example of preparation of black polyurethane coating material 11 of the present invention] Polyolefin polyol: 100 parts by weight (Polybd R-45HT manufactured by Idemitsu Petrochemical Co., Ltd., hydroxyl value: 4)
6.5 mg-KOH / g) Aromatic amine polyol: 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. polyhardener PA400, hydroxyl value: 420 m)
g-KOH / g) Crude MDI (isocyanate group content: 31% by weight):
41.7 parts by weight Inorganic pigment (calcium carbonate fine powder): 20 parts by weight Carbon black (fine powder): 1 part by weight Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 1.0

[0142] Next, as shown in FIG.
(0 mm × 200 mm × 9 mm thickness × 5 m length) 1 surface was grit blasted to remove rust, and the surface was spray-coated with the urethane primer 1 of the present invention of Example 1 so that the film thickness became 35 μm. After curing, a urethane primer layer 2 was formed and a base treatment was performed.

Next, the above-mentioned black polyurethane paint 10 or 11 of the present invention was spray-coated on the surface so as to have a thickness of 2 mm, and was cured to form a black polyurethane layer 3.

Next, the colored polyurethane coating 1 of the present invention of Example 1 was spray-coated on the surface so as to have a film thickness of 1 mm, cured, and a colored polyurethane layer 4 was laminated thereon. Pile No. 10 and 11
Were each manufactured.

Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by cutting these coated square steel pipe piles to a length of 1 m and performing an exposure test for 7 years on a river.

From the results shown in Table 1, even if the kind of the inorganic pigment in the black polyurethane layer of the present invention is changed, the surface of the colored polyurethane layer after the river exposure test is not discolored and the weather resistance is excellent.

[0147]

Example 7 The following colored polyurethane coatings 2 and 3 of the present invention were prepared by changing the type of acrylic polyol to be mixed into the colored polyurethane coating used for forming the colored polyurethane layer.

[0148]

[Preparation of the colored polyurethane paint 2 of the present invention] Acrylic polyol: 100 parts by weight (Takelac UA-902 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 17.5 mg)
—KOH / g) aliphatic isocyanate-terminated urethane prepolymer:
5.2 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Company Limited)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.5

[0149]

[Preparation of Colored Polyurethane Paint 3 of the Present Invention] Acrylic polyol: 100 parts by weight (Takelac UA-905 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 40 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
1.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Company Limited)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.5

Next, as shown in FIG. 8, the outer surface of the steel pipe sheet pile was sand-blasted to remove rust, and the urethane primer 1 of the present invention of Example 1 was spray-coated so as to have a film thickness of 30 μm. After curing, a urethane primer layer 2 was formed and a base treatment was performed.

Next, the black polyurethane paint 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 3 mm, and was cured to form a black polyurethane layer 3.

Next, the colored polyurethane paint 2 or 3 of the present invention is spray-coated on the surface so as to have a thickness of 2 mm and cured, and a colored polyurethane layer 4 is laminated to form a colored polyurethane-coated steel pipe of the present invention. Yaita No. 12
And 13 were each manufactured.

Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by cutting these coated steel pipe sheet piles to a length of 1 m and performing an exposure test for 7 years on a river.

From the results shown in Table 1, even when the type of the acrylic polyol in the colored polyurethane layer of the present invention was changed, the colored polyurethane layer surface did not fade after the river exposure test, and the weather resistance was excellent.

[0155]

Example 8 In the same manner as in Example 1, the following colored polyurethane coatings 4 and 5 of the present invention were prepared by changing the type of the aliphatic isocyanate-terminated urethane prepolymer blended in the colored polyurethane coating used for forming the colored polyurethane layer. Using the colored polyurethane-coated steel sheet pile No. of the present invention. 12 and 13 were each manufactured.

[0156]

[Preparation of Colored Polyurethane Paint 4 of the Present Invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
7.8 parts by weight (Takenate D-14 manufactured by Takeda Pharmaceutical Company Limited)
0N, isocyanate group content: 10.5% by weight) Color pigment (Co-Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.5

[0157]

[Preparation of Colored Polyurethane Paint 5 of the Present Invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
6.3 parts by weight (Takenate D-11 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 11.5% by weight) Color pigment (Co-Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.5

These coated steel sheet piles were cut to a length of 1 m,
Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by performing an exposure test on a river for 7 years.

From the results shown in Table 1, even when the kind of the aliphatic isocyanate-terminated urethane prepolymer of the colored polyurethane layer of the present invention was changed, the colored polyurethane layer surface did not fade after the river exposure test, and the weather resistance was excellent.

[0160]

Example 9 The amount of the aliphatic isocyanate-terminated urethane prepolymer blended in the colored polyurethane paint used to form the colored polyurethane layer was determined by the weight ratio of the isocyanate group (NCO) to the hydroxyl group (OH) of the acrylic polyol (NCO / OH). The following colored polyurethane paints 6 and 7 of the present invention, which were changed to 1.0 and 2.0 in the above), were prepared.

As a comparative example, the NCO / OH ratio was 0.4
And Comparative Colored Polyurethane Coatings 2 and 3 below were prepared.

[0162]

[Preparation of Colored Polyurethane Paint 6 of the Present Invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 2
9.7 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Company Limited)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 1.0

[0163]

[Preparation of colored polyurethane paint 7 of the present invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) Aliphatic isocyanate-terminated urethane prepolymer: 5
9.4 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 2.0

[0164]

Preparation of Comparative Colored Polyurethane Coating 2 The following components were blended to prepare a colored polyurethane coating of the present invention.

Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value:
50 mg-KOH / g) Aliphatic isocyanate-terminated urethane prepolymer: 1
1.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Company Limited)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 0.4

[0166]

Preparation of Comparative Colored Polyurethane Coating 3 The following components were blended to prepare a colored polyurethane coating of the present invention.

Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value:
50 mg-KOH / g) Aliphatic isocyanate-terminated urethane prepolymer: 6
2.4 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Company Limited)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
Parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above coating material: 2.1

Next, as shown in FIG.
(m width × 9 mm thickness × 5 m length) The surface is grit blasted to remove rust, and the urethane primer 1 of the present invention of Example 1 is spray-coated to a thickness of 150 μm and cured. The urethane primer layer 2 was formed.

Next, the black polyurethane paint 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 15 mm and cured, and a black polyurethane layer 3 was laminated.

Next, the colored polyurethane coating 6 or 7 of the present invention was spray-coated on the surface so as to have a film thickness of 10 mm to form a colored polyurethane layer 4. 14 and 15 were each manufactured.

As a comparative example, a colored polyurethane-coated steel sheet No. 1 using the comparative colored polyurethane paint 2 or 3 instead of the colored polyurethane paint of the present invention. 51 and 5
2 were each manufactured.

Table 1 shows the results obtained by subjecting these colored polyurethane-coated steel sheets to an river exposure test for 7 years and measuring the color difference on the surface of the colored polyurethane layer.

From the results shown in Table 1, the colored polyurethane-coated steel sheet pile No. of the present invention was obtained. Taking the results of Table 1 (Table 1, 1, Example 1) into consideration, the colored polyurethane layer of the present invention contains aliphatic isocyanate-terminated urethane prepolymer in weight of isocyanate group (NCO) with respect to hydroxyl group (OH) of acrylic polyol. 0.5 to 2.0 in specific NCO / OH
The color fading of the surface of the colored polyurethane layer after the river exposure test can be prevented only when the range is set to the range.

[0174]

Example 10 The following colored polyurethane coatings 8 to 27 of the present invention were prepared by changing the kind of the coloring pigment to be mixed into the colored polyurethane coating used for forming the colored polyurethane layer.

As a comparative example, the following comparative colored polyurethane paint 4 using an organic pigment other than the present invention as the coloring pigment was used.
~ 7 were prepared.

[0176]

Preparation of the Colored Polyurethane Coatings 8 to 27 of the Present Invention Each coating was prepared by changing only the coloring pigment of the colored polyurethane coating 6 of the present invention as follows.

[0177]

[Colored polyurethane paint 8 of the present invention] Pigment: Co alone oxide (10 parts by weight) Color tone: purple

[0178]

[Colored polyurethane paint 9 of the present invention] Pigment: Mn single oxide (10 parts by weight) Color: purple

[0179]

[Colored polyurethane paint 10 of the present invention] Pigment: Co-Cr-Al composite oxide (10 parts by weight) Color tone: blue

[0180]

[Colored polyurethane paint 11 of the present invention] Pigment: Fe-Ti composite oxide (10 parts by weight) Color: brown

[0181]

[Colored polyurethane paint 12 of the present invention] Pigment: Fe-Al-Ti composite oxide (10 parts by weight) Color: brown

[0182]

[Colored polyurethane paint 13 of the present invention] Pigment: Fe-Zn-Ti composite oxide (10 parts by weight) Color tone: brown

[0183]

[Colored polyurethane paint 14 of the present invention] Pigment: Fe-Cr-Zn-Ti composite oxide (10 parts by weight) Color tone: brown

[0184]

[Colored polyurethane paint 15 of the present invention] Pigment: Fe-Cr-Mn-Ti composite oxide (10 parts by weight) Color tone: brown

[0185]

[Colored polyurethane paint 16 of the present invention] Pigment: Mn-Cr-Sb-Ti composite oxide (10 parts by weight) Color tone: brown

[0186]

[Colored polyurethane paint 17 of the present invention] Pigment: Cr-Ni-Cu-Sb-Ti composite oxide (10
(Weight part) Color: Brown

[0187]

[Colored polyurethane paint 18 of the present invention] Pigment: Mn-Sb-Ti composite oxide (10 parts by weight) Color: brown

[0188]

[Colored polyurethane paint 19 of the present invention] Pigment: Ni-Sb-Ti composite oxide (10 parts by weight) Color tone: yellow

[0189]

[Colored polyurethane paint 20 of the present invention] Pigment: Cr-Sb-Ti composite oxide (10 parts by weight) Color tone: orange

[0190]

[Colored polyurethane paint 21 of the present invention] Pigment: Ni-Sb-Ti composite oxide (10 parts by weight) Color tone: orange

[0191]

[Colored polyurethane paint 22 of the present invention] Pigment: Ni-Co-Zn-Ti composite oxide (10 parts by weight) Color tone: green

[0192]

[Colored polyurethane paint 23 of the present invention] Pigment: Co-Zn-Ti-Cr composite oxide (10 parts by weight) Color tone: green

[0193]

[Colored polyurethane paint 24 of the present invention] Pigment: Ni-Co-Zn-Sb-Ti composite oxide (10
(Weight part) Color: green

[0194]

[Colored polyurethane paint 25 of the present invention] Pigment: Co-Cr-Mg-Al-Zn composite oxide (10
(Weight part) Color: green

[0195]

[Colored polyurethane paint 26 of the present invention] Pigment: Co-Cr-Mg-Al-Zn composite oxide (5 parts by weight), titanium oxide (5 parts by weight) Color tone: light green

[0196]

[Colored polyurethane paint 27 of the present invention] Pigment: Co-Cr-Mg-Al-Zn composite oxide (5 parts by weight), Ni-Sb-Ti composite oxide (3 parts by weight), titanium oxide (2 parts by weight) Color: yellow-green

[0197]

Preparation of Comparative Colored Polyurethane Coatings 4 to 7 Each coating was prepared by changing only the coloring pigment of the colored polyurethane coating 6 of the present invention as follows.

[0198]

[Comparative colored polyurethane paint 4] Pigment: phthalocyanine blue (10 parts by weight) Color: blue

[0199]

[Comparative colored polyurethane paint 5] Pigment: isoindolinone yellow (10 parts by weight) Color tone: yellow

[0200]

[Comparative colored polyurethane paint 6] Pigment: isoindolinone yellow (5 parts by weight), quinacridone red (5 parts by weight) Color tone: orange

[0201]

[Comparative colored polyurethane paint 7] Pigment: phthalocyanine green (10 parts by weight) Color: green

Next, as shown in FIG.
(m width x 1 mm thickness x 5 m length) The surface of the urethane primer 1 of Example 1 of the present invention is spray-coated to a thickness of 20 µm and cured by pickling and rusting the surface. A urethane primer layer 2 was formed.

Next, the black polyurethane paint 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 0.5 mm, and was cured, and a black polyurethane layer 3 was laminated.

Next, the colored polyurethane coating 8 to 27 of the present invention was spray-coated on the surface so as to have a thickness of 0.3 mm to form a colored polyurethane layer 4. . 16 to 35 were each manufactured.

As comparative examples, the comparative colored polyurethane paints 4 to 7 were used in place of the colored polyurethane paint of the present invention.
Colored polyurethane coated steel sheet No. 53-56 were each manufactured.

Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by subjecting these colored urethane-coated steel sheets to an river exposure test for 7 years.

From the results shown in Table 1, it was found that Co, Al, Cr, Fe, Ti, Zn, M
Prevents fading of the surface of the colored polyurethane layer after river exposure test only when using a colored pigment composed of an oxide or a composite oxide of one or more elements selected from n, Sb, Ni, and Mg, alone or in combination. it can.

[0208]

Example 11 The amount of the coloring pigment to be added to the colored polyurethane paint used for forming the colored polyurethane layer was 20 parts by weight and 30 parts by weight based on 100 parts by weight of the acrylic polyol.
The following colored polyurethane coating material 2 of the present invention, changed to parts by weight
8 and 29 were mixed.

As a comparative example, the addition amount of the coloring pigment was 0.5 parts by weight and 3 parts by weight with respect to 100 parts by weight of the acrylic polyol.
Comparative colored polyurethane paints 8 and 9 were prepared with 1 part by weight.

[0210]

[Preparation of the colored polyurethane paint 28 of the present invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 2
0 parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 35% by weight NCO / OH (weight ratio) of the above coating material: 0.5

[0211]

[Preparation of the colored polyurethane paint 29 of the present invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 3
0 parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 40% by weight NCO / OH (weight ratio) of the above coating material: 0.5

[0212]

[Preparation of comparative colored polyurethane paint 8] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]):
0.5 parts by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above paint: 0.5

[0213]

[Preparation of comparative colored polyurethane paint 9] Acrylic polyol: 100 parts by weight (Takerac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 3
1 part by weight Hindered amine light stabilizer: 0.5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 35% by weight NCO / OH (weight ratio) of the above coating material: 0.5

Next, as shown in FIG. 1, a steel plate (200 m
(m width × 10 mm thickness × 5 m length) The surface is grit blasted to remove rust, and the urethane primer 1 of the present invention of Example 1 is spray-coated to a thickness of 50 μm and cured. The urethane primer layer 2 was formed.

Next, the black polyurethane coating 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 3 mm, and cured, and a black polyurethane layer 3 was laminated.

Next, the colored polyurethane paint 28 or 29 of the present invention is spray-coated on the surface so as to have a thickness of 1 mm to form a colored polyurethane layer 4.
The colored polyurethane coated steel sheet No. 36 and 37 were each manufactured.

As a comparative example, a colored polyurethane-coated steel sheet No. using the comparative colored polyurethane paint 8 or 9 described above instead of the colored polyurethane paint of the present invention. 57 and 5
8 were each manufactured.

Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by subjecting these colored polyurethane-coated steel sheets to an exposure test on a river for 7 years.

From the results shown in Table 1, the colored polyurethane-coated steel sheet pile No. Taking into account the results of Table 1 (Table 1, 1, Example 1), the colored polyurethane layer of the present invention contains a colored pigment in an amount of 1 to 100 parts by weight of acrylic polyol.
Discoloration of the surface of the colored polyurethane layer after the river exposure test can be prevented only when added in the range of ３０30 parts by weight.

[0220]

Example 12 The present invention described below wherein the amount of the hindered amine light stabilizer to be added to the colored polyurethane paint used for forming the colored polyurethane layer was changed to 5 parts by weight and 10 parts by weight based on 100 parts by weight of the acrylic polyol. Of colored polyurethane paints 30 and 31 were prepared.

As a comparative example, the color pigment was added in an amount of 0.1 part by weight to 100 parts by weight of the acrylic polyol.
Comparative colored polyurethane paints 10 and 11 changed to 1 part by weight
Was prepared.

[0222]

[Preparation of colored polyurethane paint 30 of the present invention] Acrylic polyol: 100 parts by weight (Takerac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 2
0 parts by weight Hindered amine light stabilizer: 5% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 35% by weight NCO / OH (weight ratio) of the above coating material: 0.5

[0223]

[Preparation of Colored Polyurethane Paint 31 of the Present Invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 3
0 parts by weight Hindered amine light stabilizer: 10% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 40% by weight NCO / OH (weight ratio) of the above coating material: 0.5

[0224]

[Preparation of comparative colored polyurethane paint 10] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]):
0.5 parts by weight Hindered amine light stabilizer: 0.1% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 30% by weight NCO / OH (weight ratio) of the above paint: 0.5

[0225]

[Preparation of comparative colored polyurethane paint 11] Acrylic polyol: 100 parts by weight (Takerac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 3
1 part by weight Hindered amine light stabilizer: 11% by weight (Sanol LS-292 manufactured by Sankyo) Solvent: 35% by weight NCO / OH (weight ratio) of the above coating material: 0.5

Next, as shown in FIG.
(m width × 8 mm thickness × 5 m length) The surface is grit blasted to remove rust, and the surface is coated with the urethane primer 1 of the present invention of Example 1 by spray coating to a thickness of 30 μm and cured. The urethane primer layer 2 was formed.

Next, the black polyurethane coating 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 2 mm and cured, and a black polyurethane layer 3 was laminated.

Next, the colored polyurethane paint 30 or 31 of the present invention is spray-coated on the surface so as to have a thickness of 1 mm to form a colored polyurethane layer 4,
The colored polyurethane coated steel sheet No. 38 and 39 were produced respectively.

As a comparative example, a colored polyurethane-coated steel sheet No. using the comparative colored polyurethane paint 10 or 11 described above instead of the colored polyurethane paint of the present invention. 59
And 60 were each manufactured.

Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by subjecting these colored polyurethane-coated steel sheets to an river exposure test for 7 years.

From the results shown in Table 1, the colored polyurethane-coated steel sheet pile No. Taking the results of Table 1 (Table 1, 1, Example 1) into consideration, the colored polyurethane layer of the present invention contains a hindered amine light stabilizer in an acrylic polyol 10
Discoloration of the surface of the colored polyurethane layer after the river exposure test can be prevented only when 0.5 to 10 parts by weight is added to 0 part by weight.

[0232]

Example 13 The following colored polyurethane paints 32 and 33 of the present invention were prepared by changing the type of hindered amine light stabilizer to be incorporated in the colored polyurethane paint used for forming the colored polyurethane layer.

[0233]

[Preparation of the colored polyurethane paint 32 of the present invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
0 parts by weight Hindered amine light stabilizer: 1% by weight (Sanol LS-765 manufactured by Sankyo) Solvent: 35% by weight NCO / OH (weight ratio) of the above paint: 0.5

[0234]

[Preparation of the colored polyurethane paint 33 of the present invention] Acrylic polyol: 100 parts by weight (Takelac UA-702 manufactured by Takeda Pharmaceutical Co., Ltd., hydroxyl value: 50 mg-K)
OH / g) aliphatic isocyanate-terminated urethane prepolymer: 1
4.9 parts by weight (Takenate D-16 manufactured by Takeda Pharmaceutical Co., Ltd.)
0N, isocyanate group content: 12.6% by weight) Color pigment (Co—Al composite oxide [color tone: blue]): 1
0 parts by weight Hindered amine light stabilizer: 1% by weight (Sanol LS-1114 manufactured by Sankyo) Solvent: 35% by weight NCO / OH (weight ratio) of the above coating material: 0.5

Next, as shown in FIG.
(m width x 7 mm thickness x 5 m length) The surface is grit blasted to remove rust, and the surface is coated with the urethane primer 1 of the present invention of Example 1 by spray coating so as to have a film thickness of 30 µm and cured. The urethane primer layer 2 was formed.

Next, the black polyurethane paint 1 of the present invention of Example 1 was spray-coated on the surface so as to have a thickness of 2 mm and cured, and a black polyurethane layer 3 was laminated.

Next, the colored polyurethane paint 32 or 33 of the present invention is spray-coated on the surface so as to have a thickness of 1 mm to form a colored polyurethane layer 4.
The colored polyurethane coated steel sheet No. 40 and 41 were each manufactured.

Table 1 shows the results of measuring the color difference on the surface of the colored polyurethane layer by subjecting these colored polyurethane-coated steel sheets to an river exposure test for 7 years.

From the results shown in Table 1, it is possible to prevent the colored polyurethane layer of the present invention from discoloring on the surface of the colored polyurethane layer after the river exposure test even if the kind of the hindered amine light stabilizer is changed.

[0240]

[Table 1]

[0241]

[Table 2]

[0242]

[Table 3]

[0243]

As is clear from the examples, the colored polyurethane-coated steel material of the present invention has a black polyurethane layer containing carbon black, Co, Al, Cr, Fe, Ti, Zn, Mn,
It has a colored polyurethane layer containing a hindered amine-based light stabilizer and a colored pigment consisting of a single or mixture of oxides or composite oxides of one or more elements selected from Sb, Ni, and Mg. Compared with conventional colored polyurethane-coated steel, it has no change in surface color difference even after a seven-year river exposure test, and is excellent in weather resistance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a steel sheet having a black polyurethane layer and a colored polyurethane layer laminated on the surface.

FIG. 2 is a cross-sectional view showing a steel sheet pile having a black polyurethane layer and a colored polyurethane layer laminated on a mountain surface.

FIG. 3 is a cross-sectional view showing a steel sheet pile having a black polyurethane layer and a colored polyurethane layer laminated on a valley surface.

FIG. 4 is a cross-sectional view showing an H-shaped steel having a black polyurethane layer and a colored polyurethane layer laminated on the surface.

FIG. 5 is a cross-sectional view showing a steel wall for connecting walls in which a black polyurethane layer and a colored polyurethane layer are laminated on the surface.

FIG. 6 is a sectional view showing a steel pipe pile in which a black polyurethane layer and a colored polyurethane layer are laminated on the outer surface.

FIG. 7 is a sectional view showing a square steel pipe pile in which a black polyurethane layer and a colored polyurethane layer are laminated on the outer surface.

FIG. 8 is a sectional view showing a square steel pipe pile in which a black polyurethane layer and a colored polyurethane layer are laminated on the outer surface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Steel material, such as steel plate, steel sheet pile, H-section steel, wall steel for steel wall, steel pipe pile, square steel pipe pile, steel pipe sheet pile, etc. which have been subjected to blast treatment 2 Urethane primer layer 3 Black polyurethane layer containing carbon black 4 Co, Al , Cr, Fe, Ti, Zn, Mn, S
b, a colored polyurethane layer containing a colored pigment comprising a single or mixture of oxides or composite oxides of one or more elements selected from Ni, Mg and a hindered amine light stabilizer

Claims (1)

(57) [Claims] 1. A black polyurethane layer containing carbon black, Co, A
1, Cr, Fe, Ti, Zn, Mn, Sb, Ni, Mg
And a colored polyurethane layer containing a hindered amine-based light stabilizer and a colored pigment comprising an oxide or a complex oxide of one or more elements selected from the group consisting of: .