KR101316649B1 - Nanosized ceramic coating steel - Google Patents

Abstract

The present invention relates to a ceramic coated steel pipe coated with a composition for anti-corrosion coating of metal and concrete structures, comprising a two-component system comprising a layered silicate and a nano-sized glass flake as a polymer resin, a curing agent, a ceramic powder, and a filler. The nano-sized plate-shaped glass flakes have a length smaller than the thickness of the coating layer formed by the composition, and the nano-ceramic coated coating composition characterized in that it has a property that is arranged parallel to the coating surface of the coating layer Provide coated steel pipe.

Description

Nano Ceramic Coated Steel Pipe {NANOSIZED CERAMIC COATING STEEL}

The present invention relates to a nano-ceramic coated steel pipe, and more particularly, to a ceramic coated steel pipe coated with a composition for anti-corrosion coating of metal and concrete structures, comprising a layered silicate as a polymer resin, a hardener, a ceramic powder, and a filler. And a two-component system comprising nanosize plate-shaped glass flakes, wherein the nano-size plate-shaped glass flakes have a length less than the thickness of the coating layer formed by the composition and have a property arranged parallel to the coating surface of the coating layer. The present invention relates to a nano ceramic coated steel pipe coated with a coating composition.

In general, steel pipes are widely used for drinking water, domestic sewage or factory wastewater, road drainage, water supply for agricultural or industrial water, city gas, and various fluids.

The inner and outer parts of these steel pipes are coated with a coating agent in order to prevent rust and damage caused by external impact. In order to prevent corrosion and erosion, the coating agent used herein is a coating agent added with a ceramic filler that can further prevent the diffusion in the curable polymer resin having a low diffusion rate to the element or molecule causing the corrosion. come.

Most of these corrosion is caused by the penetration of moisture (H ₂ O), oxygen (O ₂ ), carbon dioxide (CO ₂ ), halogenated elements (Cl, Br, etc.), especially in components such as acid or alkali ions, ozone It is promoted by that. On the other hand, when the ceramic filler is used as described above, the diffusion of these corrosion-causing substances is prevented. That is, the addition of fillers bypasses the diffusion path of the corrosion causing material and increases the penetration length, thereby reducing the permeability of the corrosion causing material and improving the anticorrosive performance of these coatings.

As described above, the transmittance P of the coating layer to which the layered ceramic filler is added may be expressed as a function of the transmittance P ₀ of the known material, as shown in Equation 1 below.

(1)

(One)

In the above formula, ψ _f is the filler fraction, τ is a tortuosity factor indicating the degree of bending of the diffusion path.

In the case of having a plate-like filler arranged parallel to the coating layer, the factor τ representing the degree of bending of the diffusion path is given by the following equation.

(2)

(2)

In the above formula, L is the long axis length of the plate-like filler, W is the thickness of the plate-shaped filler.

Referring to Equations 1 and 2, the permeability of the corrosion-causing material through the coating layer containing the filler is determined by the permeability (P ₀ ) of the polymer matrix itself, the fraction of the filler ( ψ _f ), and the aspect ratio of the filler (L). / W).

Therefore, in order to increase the waterproof and anticorrosive performance of the coating material, a polymer base having a low permeability must be selected, and an addition fraction of a filler having a high aspect ratio must be increased. Accordingly, a variety of anticorrosive coating layers have been provided that use layered silicate materials having a thickness of several tens to tens of nanometers and having a very high aspect ratio in the polymer matrix.

However, the coating material using the nanometer-thick layered silicate material as a filler is reported to reduce the permeability of the corrosion-causing material by up to 10% compared to the coating material using only the polymer matrix. This is because the layered silicate fillers are arranged in the same direction in one micron-sized domain, but these domains are irregularly arranged in the coating layer, thereby reducing the blocking effect of the fillers. That is, when the layered silicate material added in the coating is irregularly arranged, the transmittance of the coating layer is increased as the angle formed with the coating surface increases.

Therefore, in order to reduce the permeability of the corrosion causing material through the coating layer to improve the anti-corrosion performance, the aspect ratio (L / W) of the added layered filler must be greater than several hundreds and they are arranged parallel to the coating surface. Should be. However, the aspect ratios of currently available layered silicate materials generally range from about 6 to 40 (E. Picard et al, Journal of Membrane Science 292 : 133-44 (2007), and these materials are parallel to the coating layer). There is a problem that it is difficult to arrange uniformly in the direction.

In this regard, a method of arranging the plate-shaped filler in parallel with the coating layer is disclosed in US Pat. No. 4,443,503. In other words, a plate-shaped glass flake having a sufficiently large aspect ratio is used to be arranged in parallel with the coating layer. To this end, the patent has a long axis length of the plate-like filler should be similar to or longer than the thickness of the coating layer, the coating layer using a filler having such a large aspect ratio is significantly improved compared to the conventional coating layer irregular filler (anti -corrosion) property.

However, the use of a filler having a length similar to or longer than the thickness of the coating layer has some problems as follows.

First, the filler may protrude to the surface of the coating layer, or the filler may prevent the level of the coating layer from being leveled, thereby making the surface of the coating layer not smooth. Therefore, the use of the filler of such a long length will cause a poor appearance of the coating layer.

Second, pore trapping easily occurs in the coating layer during the coating process, which causes a lot of defects such as pin holes. Most coating layers generally use a spray, brush, applicator or the like to form a film, in which air bubbles are generated or collected in the coating layer. Most of these bubbles are usually suspended and removed from the top of the coating layer by buoyancy. However, as the length of the long axis of the filler increases, the probability of bubbles being collected by the filler increases, which leads to a decrease in performance due to defects in the coating layer such as pinholes.

Finally, when the coating layer contains volatiles, the diffusion of these volatiles to the outside is hampered by the filler, which increases the drying and curing time of the coating layer. This increases the working time of the coating, which leads to an increase in the process cost.

Therefore, there is a high need for the development of a coating composition and a steel pipe coated with the coating composition while reducing the permeability of the corrosion causing material.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

The inventors of the present application are a ceramic coated steel pipe coated with a composition for anti-corrosion coating of metal and concrete structures after extensive research and various experiments, and applied to steel pipes based on the characteristics of the coating agent. It was confirmed that the problems of the prior art can be solved by the nano-ceramic steel pipe that satisfies various properties required for workability and steel pipe, and have completed the present invention.

Nano-ceramic coated steel pipe according to the present invention for achieving this object is a ceramic coated steel pipe coated with a composition for anti-corrosion coating of metal and concrete structures, layered as a polymer resin, a curing agent, a ceramic powder, and a filler And a two-component system comprising silicate and nanosize plated glass flakes, wherein the nanosize plated glass flakes have a length less than the thickness of the coating layer formed by the composition and are arranged parallel to the coating surface of the coating layer. It may be composed of a coating composition having a coating composition.

When forming a predetermined coating layer on metal and concrete structures using the coating composition, it is not clear why the plate-shaped glass flakes having a length smaller than the thickness of the coating layer are arranged parallel to the coating surface of the coating layer. However, it is estimated as follows in the range which the scope of the present invention is not interpreted limitedly.

When the layered silicate and the plated glass flakes are added together, it is thought that such a regular arrangement of the fillers occurs due to the constraining effect of the layered silicates located between the layers on which the plated glass flakes are arranged. Specifically, it is expected that the layered silicate is positioned between the plate glass flakes to constrain the movement of the plate glass flakes, thereby exhibiting the effect of arranging the plate glass flakes in a constant direction.

This phenomenon is an unexpected phenomenon in the situation where the technique using the layered silicate and the technique using the plated glass flakes are known, respectively, and the present invention cannot be obtained by a simple combination of these prior arts. Prove it.

The polymer resin may be used without limitation so long as it is a polymer resin having a low diffusion rate for an element or molecule causing corrosion. In one preferred example, the polymer resin may be a thermoplastic epoxy resin. More preferably, it may be a CTBN (Carboxyl terminated polybutadiene acrylonitrile copolymer) modified epoxy resin.

Therefore, since the thermoplastic epoxy resin itself has a low viscosity, unlike the general-purpose thermosetting resin, the thermoplastic epoxy resin does not need a non-reactive diluent because the viscosity of the coating agent is low, so it is difficult to prepare a solvent-free type (100%) that does not need dilution or melting. It is easy, and because the coating agent is ductile, there is an advantage in excellent bending resistance and impact resistance.

The polymer resin may be included in 30 to 50% by weight based on the total weight of the composition. If the content is less than 30% by weight, the absolute amount of the resin is insufficient, so that it may not act as a binder as a matrix, and thus the crosslinking density may be lowered when crosslinking with the curing agent, resulting in deterioration of physical properties such as acid resistance and alkali resistance. In the case of more than 50% by weight, the flowability is increased and the content of other components is insufficient, resulting in poor physical properties and workability.

The thermoplastic epoxy resin may be selected from the group consisting of bisphenol F type epoxy resin, bisphenol A type epoxy resin, and hydrogenated bisphenol A type epoxy resin.

The curing agent is not particularly limited as long as it allows the polymer resin to be cured at room temperature. Preferably, the curing agent may be an amine curing agent, and preferably, a modified substituted amine.

The amine-based curing agent may be included in 10 to 30% by weight based on the total weight of the composition. The above composition range is an appropriate ratio for adjusting the equivalence ratio with the polymer resin, preferably 1: 1. When one component is present in excess, an unreacted excess of substance remains in the composition, resulting in slow drying and low crosslinking density. Physical properties such as water resistance and weather resistance may be poor.

The ceramic powder may use one or more selected from the group consisting of titanium oxide, talc, calcium carbonate, and silica having a particle size distribution in the range of 0.2 to 50 μm, and the ceramic powder is a pigment component in paint to provide color, hiding power, and durability. It can play a role of improving, enhancing mechanical strength, improving workability and adjusting gloss.

In addition, the ceramic powder may be included in 10 to 30% by weight based on the total weight of the composition. If the content is less than 10% by weight, the mechanical strength may be lowered. If the content is less than 50% by weight, it may be difficult to manufacture the paint by exceeding the critical pigment volume concentration, and the coating film properties may be sharply lowered.

The layered silicate is, for example, at least one selected from the group consisting of montmorillonite, mica, kaolinite and vermiculate, and preferably has a particle size distribution in the range of 0.1 to 30 μm. .

As described above, the plate-shaped glass flake has a length smaller than the thickness of the coating layer formed by the composition, it is preferable that the average length of the long axis is 1/4 or less than the thickness of the coating layer. Therefore, in the prior art as described above, it is possible to solve the problems caused by the length of the long axis being larger than the thickness of the coating layer.

In addition, the plate-shaped glass flakes may be included in 1 to 20% by weight based on the total weight of the composition. When included in less than 1% by weight it may be difficult to properly exhibit the intrinsic function of the plate-shaped glass flakes, when exceeding 20% by weight may increase the viscosity may be poor workability. More preferred content range may be 2 to 10% by weight.

In the above structure, the plate-shaped glass flakes may have an average length of long axis of 10 to 50 μm and a thickness of 0.1 to 0.5 μm.

Since the layered silicate is exfoliated and uniformly dispersed in a plate form composed of a single layer to several tens of layers in the composition including the polymer resin, it is important that the organic layered silicate is intercalated with an organic material. Preference is given to using organic silicates materials.

In some cases, a conventional method such as high speed / high temperature stirring and ultrasonic dispersion may be applied to the material.

The layered silicide is preferably included in an amount of 1 to 20% by weight based on the total weight of the composition. When it is included in less than 1% by weight it may be difficult to express the blocking effect of the filler, when it exceeds 20% by weight may increase the viscosity sharply it is difficult to manufacture the paint and the film properties may be sharply lowered. More preferred content range is 2 to 7% by weight.

The coating composition may include (a) a main component of a polymer resin, ceramic powder, layered silicate, plate glass flakes, additives, and a reactive diluent; And (b) a curing agent mixed with an amine curing agent, a ceramic powder, a layered silicate, a plate glass flake, an additive, and a diluent.

In the above structure, the main component (a) and the curing component (b) are mixed in a ratio of 1: 3 to 3: 1 by volume, and the polymer resin in the main component (a) and the amine curing agent in the curing component (b) The equivalence ratio of may be 2: 1. This range can be determined in the range in which the equivalent ratio of the polymer resin in the main component (a) and the amine-based curing agent in the curing component (b) is preferably adjusted to 1: 1.

The additive is included in the composition for formation of the coating film, improvement of the coating film properties and workability improvement, and an antifoaming agent, a dispersant, a plasticizer, a thickener, an antisettling agent, an adhesion promoter, a coupling agent, and the like may be used.

More preferably, the additive may be included in the composition at 2 to 10% by weight based on the total weight of the subject component (a) and 1 to 6% by weight based on the total weight of the curing component (b). If the amount is less than the above range, problems may occur in the coating film and workability, and in the case of exceeding the above range, cratering or deterioration of the coating film may occur.

The reactive diluents adjust viscosity to improve workability, control film thickness and contribute to the storage stability of the coating material. Such diluent is not particularly limited as long as it is a substance capable of achieving the above object. Non-limiting examples of which may be used as a diluent include reactive diluents such as butylglycidyl ether, phenylglycidyl ether, aliphatic glycidyl ether (C ₁₂ to C ₁₄ ), and the like.

The reactive diluent may be included in the composition in each of the subject component (a) and the curing component (b) at 1 to 15% by weight, based on the weight of each. If it is included in less than 1% by weight, the dilution effect is low, the viscosity may be high and stirring may not be possible. If it exceeds 15 parts by weight, the viscosity of the composition is excessively reduced, making it difficult to secure the thickness of the coating film and adhesion may be reduced. have.

In the composition, the ceramic powder, layered silicate and nano-size plate glass flakes, additives, diluents, etc., which are included in both the main component (a) and the curing component (b) may be the same kind or different from each other. Of course.

On the other hand, the thickness of the coating layer may be 200 to 500 ㎛. This coating layer is characterized in that the plate-shaped glass flakes are arranged parallel to the coating surface, as described above.

Since the dry coating thickness obtained in one painting operation is about 100 to 500 µm, when the dry coating thickness is larger than the thickness range of 500 µm, the coating thickness is thick and the durability is excellent, but the number of painting operations increases and the working time is increased. Due to the long, there is a problem that the field workability and productivity is low, and when the dry coating thickness is less than 100 ㎛ thickness has the advantage of shortening the working time, but there is a problem that the dry film thickness is thin, durability and corrosion resistance is poor. In other words, if the thickness is less than 100 μm, the coating film does not endure for a long time and wears out, so a problem of having to repaint frequently occurs.

As described above, the nano-ceramic coated steel pipe according to the present invention is coated with a composition for anti-corrosion coating of metal and concrete structures, and the added filler is arranged parallel to the coating surface to provide excellent anticorrosive performance. It prevents the occurrence of defects such as pinholes in the coating layer, and lowers the content of the inorganic material added in the coating layer, thereby preventing blurring defects of the coating layer due to the decrease in density and viscosity, thereby increasing productivity and excellent overall performance of the anticorrosive coating. Can be provided.

1 is a flowchart illustrating the steps of the coating process of the steel pipe using the nano-ceramic coating agent according to the present invention;
2 is a schematic side view of a coating apparatus for manufacturing a steel pipe using a nano-ceramic coating agent according to the present invention;
Figure 3 is a photograph of the cross-sectional microstructure of the coating layer of Example 1 observed with a scanning electron microscope.

Hereinafter, the present invention will be described in detail with reference to Examples and the like, but the scope of the present invention is not limited thereto.

FIG. 1 is a flowchart schematically illustrating a procedure of a coating process of a steel pipe using a nano ceramic coating according to the present invention, and FIG. 2 is a painting apparatus for manufacturing a steel pipe using a nano ceramic coating according to the present invention. A schematic side view of is shown.

Referring to these drawings, the steel pipe according to the present invention is transported and seated on the conveyor (S 100) to perform the coating operation.

The coating device is formed with a nano-ceramic coating 210 and an injector 200 for injecting the nano-ceramic coating 210, the nano-ceramic coating 210 is along the feed pipe 220 through the injector 200 Transferred.

In addition, the nano ceramic coating 210 transferred to the transfer pipe 220 is sprayed through the injection nozzle 230, the shot blasting is performed (S 200).

Here, the outer pipe layer 120 and the inner coating layer 110 is formed on the inside / outside of the steel pipe body portion 100 seated on the conveyor, the steel pipe body portion 100 is rotated in the direction of the arrow and in the front / rear direction Moving and shot blasting is performed.

Therefore, the inner coating layer 110 of the steel pipe body portion 100 may be uniformly coated by the nano-ceramic coating 210 is injected through the injection nozzle 230 (S 300).

≪ Example 1 >

45 parts by weight of CTBN modified epoxy resin (Kukdo Chemical KR-207, epoxy equivalent 190g / eq), 25 parts by weight of ceramic powder (titanium oxide, silica, talc, calcium carbonate, mica), layered silicate (Southern Clay Products (Cloisite 93A) ) 5 parts by weight, nano-size plate glass flakes (ECR glass flake from Glass flake limitted), 5 parts by weight of additives (defoamer, dispersant, plasticizer, leveling agent, thickener, coupling agent) and 10 parts by weight of reactive diluent Subject ingredient (a) was prepared.

In addition, 50 parts by weight of modified alicyclic amine (Ancamine 2280, manufactured by Air Products), 20 parts by weight of ceramic powder (equivalent), 5 parts by weight of layered silicate (homologous), 10 parts by weight of nano-size plate-shaped glass flakes (homologous), additive (defoamer) , 5 parts by weight of a dispersant, a plasticizer, and a water absorbent) and 10 parts by weight of a reactive diluent were mixed to prepare a cured component (b).

The coating composition was prepared by mixing the main component (a) and the curing component (b) prepared in the above in a 2: 1 (volume ratio).

≪ Comparative Example 1 &

A coating composition was prepared in the same manner as in Example 1, except that the layered silicate and the nano-size plate glass flakes were not added.

Comparative Example 2

A coating composition was prepared in the same manner as in Example 1, except that 10 parts by weight of the nano-size plate-shaped glass flakes were added to the main component and the curing agent without adding the layered silicate.

The compositions of Example 1, Comparative Examples 1 and 2 are shown in Table 1 below.

Example 1 Comparative Example 1 Comparative Example 2 Remarks Theme ingredients
(a) Epoxy resin 45 45 45 Kukdo Chemical KR-207 Ceramic powder 25 25 25 Titanium oxide, silica, talc, calcium carbonate, mica Layered silicate 5 0 0 Southern Clay Products Cloisite 93A Lamellar glass flakes 10 0 10 Glass flake limited
(ECR glass flake) additive 5 5 5 Defoamer, dispersant, plasticizer, leveling agent, thickener, coupling agent diluent 10 10 10 Reactive diluent, Curing Ingredient
(b) Modified alicyclic amines 50 50 50 Air Products
Ancamine 2280 Ceramic powder 20 20 20 Homology Layered silicate 5 0 0 Homology Lamellar glass flakes 10 0 10 Homology additive 5 5 5 Defoamer, dispersant, plasticizer, water absorbent diluent 10 10 10 Homology

Experimental Example 1 Microstructure of Coating Surface

The compositions of Example 1 and Comparative Example 2 were coated with a thickness of 300 μm on a steel sheet base by airless spray method according to the process sequence of FIG. 1, and cured at room temperature for 24 hours. Observed. The microstructure of the coating layer of Example 1 is shown in FIG. 3.

Referring to FIG. 3, the added plate glass flakes are mostly arranged almost parallel to the coating surface so that only the cross section of the plate glass flakes can be observed, and the white fine structure observed between the glass flakes is the layered silicate filler. .

Thus, by mixing the layered silicate material and the nanometer-sized plate glass flakes as a filler, the effect of arranging the glass flakes parallel to the coating surface is obtained.

Experimental Example 2 Waterproof / Anticorrosive Performance Experiment

After coating the composition of Example 1, Comparative Example 1 and Comparative Example 2 in the same manner as Experimental Example 1, the basic physical properties of the coating layer and the moisture permeability and corrosion resistance were measured and shown in Table 2 below.

In the basic property test items, the pinhole test was conducted according to the test method of NACE RP 0188, the flexural and impact properties of KS D 8502, the adhesion test of ASTM D 4541, and the wear resistance of ASTM D 4060.

Moisture permeability was measured according to the method specified in ASTM F-1249 standard using the PERMATRANS-W Model 3/61, a moisture permeability measuring device of MOCON. Multiple cycle corrosion resistance test The corrosion performance was evaluated according to the test method of KSM ISO 11997-1.

Example 1 Comparative Example 1 Comparative Example 2 Remarks Pinhole Good Good Good Flexibility Good Fine cracks Good 1200-1500 V Impact Good Good 1㎠ 650g / 2400mm Adhesiveness 9.3 8.1 7.4 N / mm < 2 & Wear resistance 44 75 63 Cs17,1kg, 1000cycles
(Mg loss) Moisture permeability 1.2 310 13 g / m ² day Compound Cycle Corrosion Resistance 0.0% 4.2% 0.5% 300 hours
50 cycles

Referring to Table 2, it can be seen that the coating layer prepared with the composition of Comparative Example 2 can obtain a significant decrease in the moisture permeability compared to Comparative Example 1. This is because the nanometer-thick glass flakes provide excellent moisture barrier.

However, it can be seen that the water permeability of the coating layer prepared with the composition of Example 1 is further reduced than Comparative Example 2. The dramatically reduced permeability is because the fillers added to the diffusion of these ions are regularly arranged parallel to the coating surface, effectively blocking the material diffused vertically through the coating layer.

In addition, it can be seen that the corrosion resistance also increases similarly to the decreasing tendency of moisture permeability. That is, the plate glass flakes arranged parallel to the coating layer increase the blocking resistance to various ions causing moisture and corrosion, and the waterproof / corrosion performance of the coating is improved.

Although described with reference to the drawings according to an embodiment of the present invention, those of ordinary skill in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (14)

A ceramic coated steel pipe coated with a composition for anti-corrosion coating of metal and concrete structures, comprising a two-component system comprising a layered silicate and nanosized glass flakes as a polymer resin, a hardener, a ceramic powder, and a filler, The nano-size plate-shaped glass flake has a length less than the thickness of the coating layer formed by the composition, the average length of the major axis is 1/4 or less than the thickness of the coating layer, and comprises 1 to 20% by weight based on the total weight of the composition , Nano ceramic coated steel pipe coated with a coating composition, characterized in that it has a property that is arranged parallel to the coating surface of the coating layer. According to claim 1, wherein the polymer resin is a thermoplastic epoxy resin, the nano-ceramic coated steel pipe coated with a coating composition, characterized in that it comprises 30 to 50% by weight based on the total weight of the composition. The nano-ceramic coated steel pipe coated with a coating composition according to claim 2, wherein the thermoplastic epoxy resin is selected from the group consisting of bisphenol F type epoxy resins, bisphenol A type epoxy resins, and hydrogenated bisphenol A type epoxy resins. . According to claim 1, wherein the curing agent is an amine-based curing agent, the nano-ceramic coated steel pipe coated with a coating composition, characterized in that contained in 10 to 30% by weight based on the total weight of the composition. According to claim 1, wherein the ceramic powder is one or more selected from the group consisting of titanium oxide, talc, calcium carbonate, silica in the particle size distribution range of 0.2 to 50 ㎛, 10 to 30% by weight based on the total weight of the composition Nano ceramic coated steel pipe coated with a composition for coating, characterized in that it comprises a. The method of claim 1, wherein the layered silicate is at least one selected from the group consisting of montmorillonite, mica, kaolinite and vermiculate, has a particle size distribution in the range of 0.1 to 30 μm, and the composition as a whole. Nano ceramic coated steel pipe coated with a coating composition, characterized in that contained in 1 to 20% by weight based on the weight. delete  The nano-ceramic coated steel pipe of claim 1, wherein the plate-shaped glass flakes have an average length of 10 to 50 µm and a thickness of 0.1 to 0.5 µm. The nano-ceramic coated steel pipe coated with a coating composition according to claim 1, wherein the layered silicate is made of an organic layered silicate material which is intercalated with an organic material. 10. The nano ceramic coated steel pipe of claim 9, wherein the material is manufactured by high speed / high temperature stirring or ultrasonic dispersion. The composition of claim 1, wherein the coating composition comprises: (a) a main component of a polymer resin, ceramic powder, layered silicate, plate glass flakes, additives, and reactive diluents; And (b) an amine-based curing agent, a ceramic powder, a layered silicate, a plate-shaped glass flake, an additive and a diluent, and a curing agent. 12. The curable component (a) and curable component (b) are mixed in a ratio of 1: 3 to 3: 1 by volume, and the polymer resin and curable component (b) in the curative component (a) Nano-ceramic coated steel pipe coated with a coating composition, characterized in that the equivalent ratio of the amine curing agent is 2: 1. The method of claim 11, wherein the reactive diluent is butyl glycidyl ether, phenyl glycidyl ether, and aliphatic glycidyl ether (C ₁₂ ~ C ₁₄ ) is coated with a coating composition, characterized in that Nano ceramic coated steel pipe. The nano-ceramic coated steel pipe of claim 1, wherein the coating layer has a thickness of 200 to 500 µm.

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