KR101702118B1 - Environment-friendly heavy duty steel paint composition and heavy duty steel coating method of steel material structure using the same - Google Patents

Abstract

The present invention relates to an eco-friendly heavy duty paint composition for steel, and to a coating method using the same. The eco-friendly heavy duty paint composition for steel is capable of extending lifespan of steel structures owing to extended lifespan of heavy duty coating films by applying hydrophobic eco-friendly paint which exhibits enhanced properties such as adhesiveness, antirust properties, corrosion resistance, impact resistance, flame retardance (self-extinguishability), chemical resistance, antipollution properties, chloride resistance, waterproofness, and weatherability. To this end, the eco-friendly heavy duty paint composition contains a hydrophobic eco-friendly oil-based epoxy resin, a flame retardant, a pyroligneous liquor, a silane compound, and zinc powder.

Description

[0001] The present invention relates to an environment-friendly heavy duty steel paint composition and a steel material structure using the same,

The present invention relates to an environmentally friendly heavy-weight coating composition for steel structures, and more particularly, to an environmentally-friendly heavy-weight coating composition for steel structures which comprises an epoxy resin, a flame retardant, a wood vinegar, a silane compound, ), An environmentally friendly heavy-duty coating composition which increases the chemical resistance, pollution-preventing property, flame-retarding property, water-proofing property and weather resistance, and prolongs the life of the heavy-weight coating film and prolongs the life of the steel material structure, .

In general, bridges or structures made of steel are likely to be exposed to natural environments for a long period of time and are susceptible to corrosion. Therefore, studies for preventing corrosion by applying paints to the surfaces of bridges or structures have been steadily conducted.

However, in the case of paints containing organic solvents, workers are threatening the health of paint painters due to unprotected exposure to organic solvents in the workplace. In addition, as the global environment rapidly deteriorates, many Damage is occurring, and there is a need for research and development on environmentally friendly paints to safely and revive the environment of the earth.

In Korea, we make performance standards suitable for environmentally friendly products and apply them to all products to produce products that meet the standard. Especially, recently, regulations on VOCs against air pollution are strengthening internationally, and development of environmentally friendly paints is required.

Conventionally used environmentally friendly paints are classified into water-soluble type emulsified with a surfactant and non-solvent type without an organic solvent. The water-soluble type has permeability and air permeability, so that internal corrosion due to moisture penetration causes the steel to be used as a heavy- Non-solvent-based oil-based paints are excellent in adhesion to steel, impact resistance and durability, and are excellent in water resistance because they are hydrophobic. The development of environmentally friendly paints that do not use solvents as described above has been more urgently required in metropolitan areas and coastal areas where air pollution is severe.

The heavy paint of steel structure is applied with chlorine rubber paint in the beginning, and the zinc epoxy paint or the inorganic zinc paint is painted on the steel surface for the purpose of life extension, workability and economical efficiency, and the acrylic paint or fluorine paint is applied on the top Respectively. However, the fluorine system has a long durability life and excellent stain resistance, but the application of fluorine-based coatings has been reduced due to delamination problems in repair work. In addition, the acrylic system is excellent in weatherability, but is not suitable for heavy-duty paints because of low acid resistance, impact resistance, chemical resistance, etc. [Japanese Patent Laid-Open No. 2002-06913]. As an alternative to such a problem, a ceramic coating material was developed and applied, but the outer appearance of the coating film was good due to the breathability due to the breathability, but the corrosion occurred in the inner steel structure structure. That is, the ceramic-based heavy-duty paint is good for 6 to 8 years, but thereafter, there is a problem in that corrosion occurs in the inner steel due to permeation of water and penetration of water into fine cracks.

Recently, as disclosed in Japanese Patent Application Laid-Open Nos. 2001-040279 and 2001-040279, water-based urethane resin coatings and water-based epoxy resin coatings are applied by the environmentally friendly heavy paint method. However, as a result, the durability life is short due to the problem of permeability and air permeability, and thus it is recognized as a nonconforming method as a heavy-duty paint. In addition, the polyurea paint has good workability, but it is difficult to apply because it is not an eco-friendly paint.

Korean Patent Laid-Open Publication No. 2002-0054756 discloses a water-soluble coating composition for coating an electrogalvanized steel sheet. However, such a water-soluble type coating composition has problems of permeability and air permeability, resulting in internal corrosion due to moisture penetration, Japanese Patent Application Laid-Open No. 2002-121471 discloses a problem that workers are exposed to organic solvents in an unprotected manner due to volatility using an organic solvent as an essential component.

Japanese Patent Application Laid-Open No. 2002-06913 Japanese Patent Application Laid-Open No. 2001-040279 Japanese Patent Application Laid-Open No. 2001-040279 Korean Patent Publication No. 2002-0054756 Japanese Patent Application Laid-Open No. 2002-121471

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art as described above, and it is an object of the present invention to provide an environmentally friendly epoxy resin which is improved in rust prevention property, adhesion property and antifouling property by including environmentally friendly epoxy resin, flame retardant agent, wood vinegar, silane compound and zinc powder And a coating method using the same.

In order to achieve the above object, a coating composition according to one embodiment of the present invention comprises 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a wood vinegar, 5 to 100 parts by weight of a silane compound, To 500 parts by weight.

The epoxy resin may be at least one selected from the group consisting of a bisphenol A epoxy resin, a bisphenol F epoxy resin and a plastic epoxy resin.

The flame retardant may be at least one selected from antimony oxide, tetrabromobisphenol (TBBA), and alumina hydroxide.

The vinegar solution may be at least one kind selected from the group consisting of oak wood vinegar, bamboo wood vinegar, pine wood vinegar (sesame oil) and oak (acetic acid).

The silane compound may be at least one selected from the group consisting of methoxysilane, gamma -glycidoxypropyltrimethoxysilane, gamma -glycidoxypropyltriethoxysilane, gamma -glycidoxypropylmethyldimethoxysilane, gamma- (3,4-epoxycyclo Hexyl) ethyl triethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

According to another embodiment of the present invention, the environmentally friendly heavy painting method may include the following steps:

(1) a surface treatment step of removing contaminants on the surface of steel;

(2) first coating the surface of the steel material with the coating composition of the present invention;

(3) secondarily applying the coating composition of the present invention onto the surface of the substrate coated in step (2); And

(4) After the secondary application step, the urethane application step is carried out once or more with aqueous urethane.

In the environmentally friendly heavy paint coating method according to the present invention, the coating composition used in the step (2) is a coating composition comprising 100 parts by weight of at least one epoxy resin selected from a bisphenol A epoxy resin, a bisphenol F epoxy resin and a plastic epoxy resin The coating composition may contain 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a wood vinegar, 5 to 100 parts by weight of a silane compound, and 300 to 500 parts by weight of a zinc powder. The coating composition used in the step (3) 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a vinegar solution, 5 to 100 parts by weight of a silane compound, and 300 to 500 parts by weight of a zinc powder, based on 100 parts by weight of the flame retardant.

In the environmentally friendly heavy painting method according to the present invention, step (3) is performed within 12 to 24 hours after the step (2), and step (4) is performed within 12 to 24 hours after the step (3) .

In the environmentally friendly heavy coating method according to the present invention, the step (4) may be performed by applying the aqueous urethane in a primary coating and then applying the secondary coating in 12 to 24 hours.

In the eco-friendly heavy coating method according to the present invention, the thickness of each of the applied paints may be 50 to 150 탆 in the steps (2), (3) and (4).

In the environmentally friendly heavy coating method according to the present invention, the application method may be selected from air spray coating, dip coating, roll coating, casting coating, air knife coating, calendar coating and spin coating.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided an environmentally friendly heavy-duty paint composition that contributes to the recovery of the global environment as an environmentally friendly heavy-duty paint, has good workability and does not affect worker health.

Further, according to the steel painting method of the present invention, an epoxy coating film which is weak to ultraviolet rays is applied to the upper side, and an aqueous special urethane coating material excellent in weatherability and antifouling property is applied and finished to thereby provide durability, corrosion resistance, rust resistance, chemical resistance, , Water resistance, weather resistance, impact resistance, etc. can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a coating method and a cross section of a laminated layer according to one embodiment of the present invention. FIG.
2 is a view showing a coating method and a cross section of a laminated layer according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, the coating composition of the present invention and the coating method using the same will be described in detail.

The coating composition according to the present invention may contain 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a wood vinegar, 5 to 100 parts by weight of a silane compound and 300 to 500 parts by weight of a zinc powder, based on 100 parts by weight of the epoxy resin.

The epoxy resin may include at least one selected from the group consisting of a bisphenol A epoxy resin, a bisphenol F epoxy resin and a plastic epoxy resin. The epoxy resin may be an organic solvent containing volatile substances (VOC), amines, It can be used as an environmentally friendly paint material.

The bisphenol A-based epoxy resin is a bisphenol A-based epoxy resin having an epoxy equivalent of 150 to 200 g / eq. There is no particular limitation on the type of bisphenol A epoxy resin. For example, bisphenol A diglycidyl ether may be used. YD-128S (Kukdo Chemical), YD-134 (Kukdo Chemical), YD-134 (Kukdo Chemical), YD- Kukdo Chemical), YD-128M (Kukdo Chemical), and YD-011 (Kukdo Chemical).

The bisphenol F type epoxy resin is a resin having hydrogen (H) in place of the methyl group (-CH ₃ ) in the molecule of the bisphenol A type and has a lower viscosity than the bisphenol A type and has excellent compatibility with other resins. And the chemical resistance. The bisphenol F type epoxy resin is a bisphenol F type epoxy resin having an epoxy equivalent of 150 to 200 g / eq. There is no particular limitation on its type, and examples thereof include bisphenol F diglycidyl ether (Kukdo Chemical), YDF-2004 (Kukdo Chemical), YDF-2001 (Kukdo Chemical), YDF-175S (Kukdo Chemical), and the like are commercially available. , YDF-175 (Kukdo Chemical) and YDF-170 (National Chemical Industry).

The above-mentioned plastic epoxy resin has an epoxy equivalent of 350 to 370 g / eq, and is an epoxy resin modified with at least one kind selected from rubber and dimer acid. The dimeric acid is not particularly limited and examples thereof include maleic acid, phthalic acid, Specific examples of the above-mentioned plastic epoxy resin include a maleic acid-modified epoxy resin and a phthalic acid-modified epoxy resin.

The flame retardant is not particularly limited and may be, for example, at least one selected from antimony oxide and alumina hydroxide, preferably alumina hydroxide.

The content of the flame retardant is preferably 25 to 150 parts by weight, for example 30 to 70 parts by weight, based on 100 parts by weight of the epoxy resin. When the amount is less than 25 parts by weight, flame retardancy is not sufficient, It is not preferable because it can not suppress the release of harmful gas.

The wood vinegar is obtained by liquefying the smoke from the process of making charcoal into wood and then removing the toxic and harmful substances by aging for 6 months or longer. It has a pale red color and strong smell. The picking method is to burn wood, and when yellowish white smoke comes out, it closes the entrance of the kiln leaving only small vents. The smoke contacts the outside air and naturally cools down to collect the falling liquid. It is best when the temperature of the charcoal chimney reaches 85 to 120 캜. The collected vinegar is aged and separated for 6 months or more. It is separated into water-soluble and oil-soluble liquids. Water-soluble liquids are used as wood vinegar, and oil-soluble liquids are used for industrial purposes. The amount collected from a tree of about 100 kg is about 5 liters. It is acidic around pH 3. The components are 80 to 90% by weight of water and 3% by weight of acetic acid. In addition, it contains a small amount of minerals such as formic acid, fatty acid, and methanol.

The wood vinegar solution is not particularly limited and may be at least one member selected from the group consisting of oak wood vinegar, bamboo wood vinegar, pine wood vinegar (pine wood vinegar) and oak (acetic acid solution) It is preferable that 1 to 10 parts by weight, for example, 3 to 8 parts by weight, of the acetic acid in the vinegar solution is less than 1 part by weight. If the amount is less than 1 part by weight, acetic acid in the vinegar solution is adsorbed on the heavy metal and thus it is difficult to decompose heavy metals, It is not preferable to remove the toxicity. When the amount exceeds 10 parts by weight, a phenomenon of brittleness appears, plasticity is too high, the wood vinegar is acetic acid and can encourage corrosion, the excessive removal of heavy metals is no longer effective, The cost of raw materials is greatly increased, which is economically undesirable.

The silane compound improves the insulation and flame retardancy of the coating composition, and can be used to lower the occurrence of cracks because of good adhesion.

The silane compound serves as a crosslinking agent and is not specifically limited. Examples thereof include methoxysilane,? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropyltriethoxysilane 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane. The silane coupling agent is preferably selected from the group consisting of γ-glycidoxypropylmethyldimethoxysilane, γ- (3,4-epoxycyclohexyl) ethyltriethoxysilane, Or more, and preferably 3-glycidoxypropyltrimethoxysilane.

The amount of the silane compound is preferably 5 to 100 parts by weight, for example 30 to 70 parts by weight, based on 100 parts by weight of the epoxy resin. When the amount is less than 5 parts by weight, the curing property of the coating material, And if it is more than 100 parts by weight, the wettability of the coating material to the base material tends to deteriorate, and the good adhesion and the appearance of the coating film tends to be hardly obtained, which is not preferable.

The zinc powder is used to improve the rust prevention property and is used to prevent the rust from being generated during the processing or assembly of the steel material and to sufficiently exhibit the performance of the coated film thereafter. Using raw zinc made by grinding, it has excellent rust prevention because of its excellent self-sacrifice.

The amount of the zinc powder is preferably 300 to 500 parts by weight, for example, 350 to 400 parts by weight, based on 100 parts by weight of the epoxy resin. If the amount is less than 300 parts by weight, If the amount is more than 500 parts by weight, the effect is not exhibited in an excessive amount, which is economically undesirable.

The coating composition according to the present invention may further contain plasticizers, viscosity modifiers, titanium dioxide, talc, pigments and other additives in addition to the above components in the usual amounts.

The plasticizer may be at least one selected from di-n-octyl phthalate (DOP), tricresyl phosphate (TCP), triphenyl phosphate (TPP), triethyl phosphate (TEP) and chlorophosphoric acid (TCP), triphenylphosphate (TPP) and triethylphosphate (TEP), and most preferably triethylphosphate (TEP).

The viscosity adjusting agent may be at least one selected from isopropyl alcohol, N-butanol and furfuryl alcohol, and is preferably furfuryl alcohol.

Examples of the additives include antifoaming agents, defoaming agents, dispersants, leveling agents, antioxidants, stabilizers, and precipitation inhibitors.

The environmentally friendly heavy coating method according to the present invention may include the following steps:

(1) a surface treatment step of removing contaminants on the surface of steel;

(2) first coating the surface of the steel material with the coating composition of the present invention;

(3) secondarily applying the coating composition of the present invention onto the surface of the substrate coated in step (2); And

(4) After the secondary application step, the urethane application step is carried out once or more with aqueous urethane.

In one embodiment of the environmentally friendly heavy paint coating method according to the present invention, (1) the surface treatment step is a step of removing contaminants such as oil, dust, slime, and salt on the surface of the steel material, Is not particularly limited, and for example, a method such as shot blast, sand blast, grinding and pickling can be used.

In one embodiment of the present invention, the coating composition used in the step (2) is a bisphenol A-based epoxy resin, a bisphenol F-based epoxy resin, and a plastic epoxy Resin may contain 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a wood vinegar, 5 to 100 parts by weight of a silane compound and 300 to 500 parts by weight of a zinc powder, based on 100 parts by weight of the at least one epoxy resin selected from The coating composition used in step 3) comprises 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a vinegar, 5 to 100 parts by weight of a silane compound and 300 to 500 parts by weight of a zinc powder, based on 100 parts by weight of bisphenol F- In the primary coating step, at least one epoxy resin selected from bisphenol A-based epoxy resin, bisphenol F-based epoxy resin and plastic epoxy resin is used to improve the rustproofing property And, in the second coating step it is preferred it is possible to improve the corrosion resistance by using a bisphenol F-type epoxy resin.

In one embodiment of the environmentally friendly heavy paint coating method according to the present invention, it is preferable to carry out the step (2) within 14 hours after the step (1), because rust may occur if it exceeds 14 hours.

In the eco-friendly heavy painting method according to the present invention, it is preferable that the step (3) is a corrosion resistance step and the step (3) is performed within 12 to 24 hours after the step (2) If the epoxy is excessively hardened for more than 24 hours, the epoxy may not be coated well due to the plastic nature of the epoxy, and delamination may occur, which is not preferable.

In the environmentally friendly heavy coating method of the present invention, the step (4) is a step of further improving the weather resistance, antifouling property and corrosion resistance by further applying an aqueous urethane, and is carried out within 12 to 24 hours after the step (3) If the time is less than 12 hours, the epoxy may not be hardened and melted, which is undesirable. If the time exceeds 24 hours, the epoxy hardens excessively, resulting in poor application due to the plastic nature of the epoxy, And it is not preferable.

In one embodiment of the environmentally friendly heavy paint coating method according to the present invention, the step (4) is preferably carried out by coating an aqueous urethane paint twice or more. For example, after coating the aqueous urethane with water, And can be carried out by applying a secondary coating within a period of time.

In the eco-friendly heavy coating method according to the present invention, the thickness of each of the applied paints may be 50 to 150 탆 in the steps (2), (3) and (4).

In the eco-friendly heavy coating method according to the present invention, the coating method in the steps (2), (3), and (4) includes air spray coating, dip coating, roll coating, casting coating, air knife coating, Coatings.

Hereinafter, the present invention will be described in detail by way of examples to demonstrate the superiority of the environmentally friendly coating composition of the present invention. However, the following examples are for illustrative purposes only, and the present invention is not limited to the following examples.

Comparative Example  And Example

Environment-friendly steel Center type  G- CSM  Method

1) Primary work: Steelwork and cyan removal

95% of the cyan was removed with a short-ballasting device (SSPC-SP10). Then, the foreign matter was removed with a vacuum cleaner.

2) Secondary work: The first paint of the present invention

The coating composition having the composition shown in the following Table 1 was coated in a thickness of 75 탆 using air spray within 14 hours. At this time, uniform coating is carried out so as to prevent falling down.

3) Third operation: Painting secondary painting according to the present invention

A paint having the same composition as that of the paint composition shown in the following Table 1, except that bisphenol F type epoxy resin was used as an epoxy resin within 12 to 24 hours after the secondary work, Respectively. At this time, uniformly paint is applied so as to prevent falling down.

4) Fourth operation: Water-based special urethane coating

Within 12 to 24 hours after the third operation, the water-based special urethane paint excellent in weatherability and antifouling property was first coated with air spray at a thickness of 32.5 탆. Then, after 12 to 24 hours, the water-based special urethane paint was secondarily coated with air spray at a thickness of 32.5 탆.

The total thickness of the coating film was 220 탆.

The composition and physical properties of the coating composition used in the above work are shown in Table 1 below.

                                                       (Unit: parts by weight) Name of material Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Epoxy resin ^{1 )} 50 55 83 66 43 26 Epoxy resin ^{2 )} 20 15 10 17 30 37 Epoxy resin ^{3 )} 30 30 7 17 27 37 Plasticizer
(Triethylphosphate) 8 8 3 3 5 3 Alumina hydroxide 30 29 - 20 - 20 Oak wood vinegar 2 3 5 3 - 5 3-glycidoxypropyltrimethoxysilane ^{4 )} 10 10 5 - 5 5 Filler (calcium carbonate) - - 37 24 37 18 Zinc powder 350 350 350 200 350 - Eco-friendly ^{5 )} Good Good incongruity Good Good Good Flammability ^{6 )} Self-extinguishing Self-extinguishing incongruity incongruity incongruity incongruity Repeat resistance performance at low temperature and high temperature clear clear Cracking clear clear clear Chloride ion penetration resistance performance (㎜) 0.0 0.0 0.0 0.0 0.0 incongruity My permeability ^{7 )} clear clear clear clear clear clear Bond strength (N / mm2) 2.5 2.4 1.8 1.0 2.3 2.3 Appearance ^{0 )} clear clear clear clear incongruity incongruity Impact Resistance ^{11 )} clear clear incongruity clear clear clear Humidity performance clear clear clear clear clear incongruity Bending performance ^{12 )} clear clear incongruity incongruity incongruity incongruity Rust prevention performance ^{13 )} clear clear clear incongruity incongruity incongruity

1) diglycidyl ether of bisphenol A having an epoxy equivalent of 170 g / eq

2) diglycidyl ether of bisphenol F having an epoxy equivalent of 180 g / eq

3) Maleic acid-modified epoxy resin having an epoxy equivalent of 350 g / eq

4) KBM-403, manufactured by Shin-Etsu Co.

5) <Good> when the following conditions are satisfied, and <Bad> if the following conditions are not satisfied.

TVOC emission: less than 0.020 mg / ㎡ H, Indoor air quality process test standard (2010)

Toluene Emission: Less than 0.005㎎ / ㎡H, Indoor air quality process test standard (2010)

Formaldehyde Emission: Less than 0.005㎎ / ㎡H, Indoor Air Quality Process Test Standard (2010)

VOCs: 0.01 g / L, measured according to KSM ISO 11890-2: 2007 (GC / MS).

      VOCs: less than 0.0005%, measured according to ASTM D 3257-01.

      Benzene: 0.0005, measured according to ASTM D 3257-01.

      Pb: not detected, measured according to ISO 3856-1: 1984.

      Cd: not detected, measured according to ISO 3856-4: 1984.

      Hg: not detected, measured according to ISO 3856-7: 1984.

Cr: not detected, measured according to ISO 3856-5: 1984.

6) Measured according to the test conditions of UL94.

7) ~ 13) Measured according to the test conditions of KS F 4929 (2010).

Claims (11)

Wherein the composition is 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a wood vinegar, 5 to 100 parts by weight of a silane compound and 300 to 500 parts by weight of zinc powder, based on 100 parts by weight of an epoxy resin.
The method according to claim 1,
Wherein the epoxy resin is at least one selected from a bisphenol A epoxy resin, a bisphenol F epoxy resin and a plastic epoxy resin.
The method according to claim 1,
Wherein the flame retardant is at least one selected from antimony oxide, tetrabromobisphenol (TBBA) and alumina hydroxide.
The method according to claim 1,
Wherein the wood vinegar is at least one selected from the group consisting of oak wood vinegar, bamboo wood vinegar, pine wood vinegar and oak oil.
The method of claim 1, wherein
The silane compound may be at least one selected from the group consisting of methoxysilane, gamma -glycidoxypropyltrimethoxysilane, gamma -glycidoxypropyltriethoxysilane, gamma -glycidoxypropylmethyldimethoxysilane, gamma- (3,4-epoxycyclo Hexyl) ethyl triethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.
Environmentally friendly heavy paint coating method comprising the following steps:
(1) a surface treatment step of removing contaminants on the surface of steel;
(2) firstly applying the coating composition according to any one of claims 1 to 5 to the surface of the surface-treated steel material;
(3) applying the coating composition according to any one of claims 1 to 5 to the surface of the substrate in the step (2); And
(4) After the secondary application step, the urethane application step is carried out once or more with aqueous urethane. The method according to claim 6,
The coating composition used in the step (2) may contain 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a wood vinegar, 5 to 10 parts by weight of a silane compound 5 To 100 parts by weight and zinc powder 300 to 500 parts by weight,
The coating composition used in the step (3) may contain 25 to 150 parts by weight of a flame retardant, 1 to 10 parts by weight of a wood vinegar, 5 to 100 parts by weight of a silane compound and 300 to 500 parts by weight of a zinc powder per 100 parts by weight of bisphenol F- Wherein the coating is applied to the surface of the substrate.
The method according to claim 6,
Performing the step (3) within 12 to 24 hours after the step (2)
Wherein the step (4) is performed within 12 to 24 hours after the step (3).
The method according to claim 6,
Wherein the step (4) is performed by applying the aqueous urethane in a primary coating and then applying the secondary coating within 12 to 24 hours.
The method according to claim 6,
Wherein the thickness of each of the coated paints is 50 to 150 占 퐉 in the steps (2), (3), and (4).
The method according to claim 6,
In the above steps (2), (3) and (4), the coating method is selected from air spray coating, dip coating, roll coating, casting coating, air knife coating, calendar coating and spin coating Expression painting method.

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