KR101943800B1 - Coating composition for protecting metal surface and method for manufacturing metallic structure comprising coating layer for protecting surface using the same - Google Patents

Abstract

The present invention provides a method for manufacturing a metal structure comprising a step of coating a surface of the metal structure with a metal surface protective coating composition comprising an epoxy resin, an acrylic resin, a polyester resin, an amine curing agent, a silane coupling agent, a fiber reinforcing agent and a pigment, and then curing the coating to form a surface protective coating layer. The method for manufacturing a metal structure according to the present invention can enhance corrosion resistance, water resistance, and chemical resistance. The surface protective coating layer formed by coating a metal surface protective coating composition can stably prevent a change in physical properties of the metal structure due to excellent adhesive strength.

Description

TECHNICAL FIELD The present invention relates to a coating composition for protecting a metal surface and a method for producing a metal structure having a surface protective coating layer using the coating composition for protecting metallic surface,

The present invention relates to a coating composition for protecting a metal surface which can be used for protecting the surface of a metal structure for a long period of time and a method for producing a metal structure having a surface protective coating layer formed thereon.

In recent years, steel structures made of metal materials or metal structures including steel pipes are superior in durability to plastic structures manufactured using polymer resins, and are used for building materials, automobile materials, household appliances, and the like.

Generally, in order to prevent corrosion and improve durability, the metal structure may be coated with a paint containing a polymer resin on the surface of the metal structure, And a protective coating layer is formed on the surface by coating treatment. In particular, metal structures used in areas that are easily exposed to seawater, sewage or sewage have additional PE slabs installed on site in order to obtain a higher level effect.

Specifically, the surface protection technology of a metal structure using a paint uses a paint containing an organic / inorganic polymer resin such as an epoxy resin, an acrylic resin, a urethane resin, an ester resin, a fluororesin, etc., Term effects and functions can be greatly affected depending on the method and the like.

For example, KSD 8502 liquid epoxy resin coatings, ceramic coatings, silver nano coatings, etc. are used for inner surface coatings of steel pipes for water pipes used to protect the surfaces of water and wastewater pipe structures.

However, the protective coating layer formed using the above-mentioned coating material is not excellent in properties such as corrosion resistance, chemical resistance, durability, tensile strength and elastic restoring force, and has a short lifetime and cracks and corrosion are easily generated in the coating layer. Since the aged steel pipe acts as a cause of polluting the water quality and most of the steel pipes are buried in the ground due to the nature of water and sewage, replacement and repair coating are not easy. .

Korean Patent No. 10-1836645 (Publication date: Aug. 23, 2018). Korean Patent No. 10-1811372 (Published on December 22, 2017) Korean Patent No. 10-1765116 (Publication date: Jul. Korean Patent No. 10-1670437 (published on October 26, 2016).

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art as described above, and the inventors of the present invention have found that a coating composition for metal surface protection, in which a fiber reinforcing agent containing ceramic fibers is mixed with a polymer resin and an adhesive resin, Corrosion resistance, chemical resistance and the like, as well as being excellent in adhesion strength, it has been confirmed that the deterioration of the physical properties of the metal structure can be effectively prevented for a long time.

Accordingly, the present invention provides a coating composition for protecting a metal surface, which can be used for protecting the surface of a metal structure, and a method for manufacturing a metal structure having a surface protective coating layer formed using the same.

According to an aspect of the present invention, there is provided an epoxy resin composition comprising 100 parts by weight of an epoxy resin, 10 to 20 parts by weight of an acrylic resin, 20 to 50 parts by weight of a polyester resin, 10 to 20 parts by weight of an amine curing agent, To 20 parts by weight of a fiber reinforcing agent, 20 to 50 parts by weight of a fiber reinforcing agent and 10 to 20 parts by weight of a pigment is coated on the surface of a metal structure and then cured to form a surface protective coating layer And a manufacturing method thereof.

The metal structure may be at least one selected from the group consisting of etching, electrochemical treatment, sandblasting, brushing, silicon coating, and primer coating . ≪ / RTI >

The metal surface protective coating composition may further include at least one additive selected from the group consisting of flow improvers, flow improvers, dispersants, antimicrobial agents, and ceramic fillers.

In addition, the fiber reinforcing agent may include basalt fibers having a length of 0.01 to 10 mm and a diameter of 1 to 30 탆.

The present invention also relates to a resin composition comprising 100 parts by weight of an epoxy resin, 10 to 20 parts by weight of an acrylic resin, 20 to 50 parts by weight of a polyester resin, 10 to 20 parts by weight of an amine curing agent, 5 to 20 parts by weight of a silane coupling agent, And 1 to 20 parts by weight of a pigment.

According to the method for manufacturing a metal structure according to the present invention, corrosion resistance, water resistance, and chemical resistance of a metal structure can be improved by a simple method of coating a metal structure including a ferrous metal, a non- And the surface protective coating layer formed by coating the coating composition for protecting the surface of metal can be stably prevented from changing the physical properties of the metal structure for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram showing a manufacturing method of a metal structure according to Embodiment 1. FIG.

Hereinafter, the present invention will be described in detail.

The present invention relates to a resin composition comprising 100 parts by weight of an epoxy resin, 10 to 20 parts by weight of an acrylic resin, 20 to 50 parts by weight of a polyester resin, 10 to 20 parts by weight of an amine curing agent, 5 to 20 parts by weight of a silane coupling agent, And 1 to 20 parts by weight of a pigment.

The coating composition for protecting a metal surface can be coated on the surface of a metal structure including a ferrous metal, a non-ferrous metal, etc. to improve corrosion resistance, water resistance and chemical resistance of the metal structure. It is possible to stably prevent the change of the physical properties of the resin for a long time and will be described in more detail below.

The present invention provides a method for manufacturing a metal structure, comprising coating a surface of a metal structure with a coating composition for protecting a metal surface, and then curing the surface to form a surface protective coating layer.

The coating composition for protecting a metal surface may include an epoxy resin, an acrylic resin, a polyester resin, an amine curing agent, a silane coupling agent, a fiber reinforcing agent and a pigment, and has a viscosity of 20 to 2000 cps.

Specifically, the epoxy resin plays a role of forming a surface protective coating layer having excellent adhesion with a metal structure and a low hardening shrinkage ratio and thus having an excellent mechanical strength.

The epoxy resin may include bisphenol A epoxy, novolak epoxy resin, isocyanate modified epoxy resin, bisphenol F epoxy resin, etc. Preferably, the epoxy resin has an epoxy equivalent (g / eq) of 400 to 1,000 A bisphenol A type epoxy resin and a bisphenol A type epoxy resin excellent in flexibility and corrosion resistance manufactured by polymerization of epichlorohydrin and bisphenol A can be used.

The acrylic resin plays a role of forming a surface protective coating layer having a high peel strength by improving the adhesion of the coating composition for protecting a metal surface, thereby forming a surface protective coating layer having improved properties such as adhesion, water resistance and anticorrosion, Acrylate, methacrylate, glycidyl methacrylate and the like can be used. In particular, the acrylic resin may be prepared by mixing glycidyl methacrylate and methacrylate at a weight ratio of 30:70, respectively, in order to improve the bonding strength of the acrylic resin to the epoxy resin.

The acrylic resin may be contained in an amount of 10 to 20 parts by weight based on 100 parts by weight of the epoxy resin. When the content of the acrylic resin is less than 10 parts by weight, the adhesive strength with the metal structure is decreased. When the content is more than 20 parts by weight, May be deteriorated.

The polyester resin serves to improve adhesion and durability between the surface protective coating layer and the metal structure, and is exemplified by ethylene glycol, butylene glycol, and the like.

The polyester resin may be contained in an amount of 20 to 50 parts by weight based on 100 parts by weight of the epoxy resin. If the content of the epoxy resin is less than 20 parts by weight, there may arise a problem that the adhesiveness and durability are lowered. The mechanical properties may be deteriorated.

The amine curing agent serves to crosslink the epoxy resin, the acrylic resin, and the polyester resin contained in the coating composition for protecting a metal surface and to increase the intermolecular cross-linking density to cure the epoxy resin, the acrylic resin and the polyester resin, and the alkylene polyamine, the polyalkylene polyamine, Can be used.

The amine curing agent may be contained in an amount of 10 to 20 parts by weight based on 100 parts by weight of the epoxy resin. When the content of the curing agent is less than 10 parts by weight, uniform hardening of the epoxy resin does not occur, If the amount is more than 20 parts by weight, mechanical properties such as adhesion with a metal structure and durability may be deteriorated.

The silane coupling agent crosslinks the epoxy resin contained in the coating composition for protecting a metal surface and a variety of included compounds and improves the adhesion to the metal structure.

The silane coupling agent may be at least one selected from the group consisting of 2- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, -glycidoxytrimethoxysilane, -glycidoxypropyltrimethoxysilane, -glycidoxypropyl (Aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- Aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, or a mixture thereof.

The silane coupling agent may be contained in an amount of 5 to 20 parts by weight based on 100 parts by weight of the epoxy resin. When the silane coupling agent is included in an amount of less than 5 parts by weight, the adhesive strength to the metal structure is lowered, There is a problem that the physical properties are deteriorated, and when it exceeds 20 parts by weight, there is a problem that the corrosion resistance is lowered.

The fiber reinforcing agent is structurally and chemically combined with the polymer resin contained in the coating composition for protecting the surface of metal, so that the physical properties of the fiber reinforcing agent are more complex than those of the polymer resin of the metal surface protective coating composition. The protective coating composition can enhance the tensile properties and the mechanical properties, and can form a surface protective coating layer having excellent durability.

The fiber reinforcing agent may be basalt fiber, SiC fiber, carbon fiber, glass fiber, piezoelectric fiber, or a mixture thereof. , The fiber reinforcing agent having a length of 0.01 to 10 mm and a diameter of 1 to 30 m can be used.

The fiber reinforcing agent may be mixed in a proportion of 20 to 50 parts by weight based on 100 parts by weight of the epoxy resin. If the content of the fiber reinforcing agent is less than 20 parts by weight, the improvement of physical properties may not be significantly increased. The adhesive strength may be reduced and the surface protective coating layer may easily peel off.

In particular, the fiber reinforcing agent may be impregnated with an epoxy resin solution before mixing with a coating composition for protecting a metal surface. The basalt fiber prepared by impregnating the epoxy resin with the epoxy resin may exhibit a binding force and a dispersibility To thereby provide a coating composition for protecting a metal surface which exhibits uniform physical properties.

Preferably, the fiber reinforcing agent can use basalt fiber. The basalt fiber is an environmentally friendly material because it does not emit harmful substances. It is not only natural-friendly but also has excellent chemical resistance, high strength, heat resistance, water resistance, sound absorption, And can maintain a circular shape even at a high temperature of 900 DEG C or higher, so that it is easy to apply to a coating composition for protecting a metal surface.

For reference, the above-mentioned basalt fiber is a kind of inorganic fiber, which is a next generation mineral fiber made of basalt, which is an inactive rock distributed all over the world, and the magma inside the earth is leaked to the surface due to the volcanic action, The basalt ore, which is formed by cooling and solidification, is melted at a temperature of about 1500 ° C., and is made into a melt having a viscosity of 102.8 to 103 poise by drawing it into ultrafine fibers through a nozzle to have a diameter of 1 to 30 μm Fiber.

The basalt fiber may be 0.01 to 10 mm in length and 0.5 to 30 탆 in diameter. The basalt fiber may be used in a cutter (for example, A chopping machine may be used to cut the basalt fiber roving to suit the application.

Preferably, the basalt fiber is immersed in an acidic solution of sulfuric acid, hydrochloric acid or the like for 2 to 5 hours in order to improve the bonding strength with the coating composition for protecting a metal surface, And the surface-modified basalt fiber is reacted and bonded with an epoxy resin, an acrylic resin and a polyester resin to form a surface protective coating layer having excellent durability.

More preferably, the basalt fiber has an average length of 3 to 5 mm and a diameter of 0.7 to 2 탆, and the modified basalt fiber obtained by immersing in a 70% sulfuric acid solution for 3 hours can be used.

The pigment included in the coating composition for protecting a metal surface serves to impart color to the surface protective coating layer and various conventional pigments used for coating the metal structure can be used.

The pigment may be selected from the group consisting of titanium dioxide, bismuth vanadate, cyanine green, carbon black, iron oxide red, iron oxide yellow, navy blue, cyanine blue or a mixture thereof. Examples of the pigments include talc, feldspar, barium sulfate, silica, Such as calcium carbonate, magnesium carbonate, alumina, mica, wollastonite, talc, or mixtures thereof.

The pigment may be mixed in an amount of 1 to 20 parts by weight based on 100 parts by weight of the epoxy resin. When the content of the pigment is less than 1 part by weight, it is difficult to impart hue. When the content of the pigment is more than 20 parts by weight, A problem may arise.

Further, the coating composition for protecting a metal surface may further comprise necessary additives depending on the form of the metal structure for forming the surface protective coating layer, the purpose of use, and the use environment.

Specifically, the additives may further include flow improvers, flow improvers, defoamers, thickeners, dispersants, antibacterial agents, fillers, deodorants, curing aids, solvents or mixtures thereof.

The flow improver may improve the flowability of the coating composition for metal surface protection and may be contained in a proportion of 0.1 to 5 parts by weight based on 100 parts by weight of the coating composition for protecting a metal surface, A flowability improver can be used to prevent the cratering and to improve the surface tension of the coating film to improve the appearance of the coating film and to provide a coating composition for protecting the metal surface And 0.1 to 5 parts by weight based on 100 parts by weight of the polymer.

In addition, the coating composition for protecting a metal surface may further comprise a fluidity-improving agent for improving fluidity and ensuring workability. The fluidity-improving agent may be a polypropylene-based wax, a hydrophilic or hydrophobic silica, And may be contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the metal surface protective coating composition.

The metal surface protective coating composition may further comprise a dispersing agent such as an amide-based, polypropylene-based, olefin-based or teflon-based wax for smooth dispersion between the respective components, May be contained in a proportion of 0.1 to 5 parts by weight based on 100 parts by weight of the coating composition.

In addition, the coating composition for protecting a metal surface may further include a ceramic filler. Since the ceramic filler forms a dense coating film between the cross-links formed by the reaction between the polymer resin and the curing agent component, the water resistance and the mechanical properties are improved And also has an antimicrobial-increasing effect due to its own characteristics.

The ceramic filler may include feldspar, barium sulfate, silica, alumina hydroxide, titanium dioxide, calcium carbonate, magnesium carbonate, alumina, mica, wollastonite, talc or mixtures thereof. The metal surface protective coating composition may contain the ceramic filler in a proportion of 5 to 20 parts by weight based on 100 parts by weight of the coating composition for protecting a metal surface. When the content of the ceramic filler is less than 5 parts by weight, sufficient mechanical properties are expected to be improved And if it is more than 20 parts by weight, the tensile property and the bending property may be deteriorated.

In addition, the curing aid may be added to control the curing rate and curing degree of the coating composition for protecting the surface of metal, which may compensate the mechanical properties of the surface protective coating layer, and metal chelates and the like may be exemplified. Is preferably contained in a proportion of 0.01 to 1 part by weight based on the weight part.

The above-mentioned metal surface protective coating composition is excellent in properties such as water resistance, corrosion resistance, chemical resistance and the like as well as excellent adhesive strength and mechanical It is possible to prevent the surface of the metal structure from being corroded and cracked for a long time.

The solvent may be included in order to ensure properties such as flowability, workability, and dispersibility of the coating composition for protecting a metal surface. Examples of the solvent include butyl alcohol, ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, benzene, toluene, , Chlorobenzene, chloroform, methylene chloride, tetrachlorethylene, butyl acetic acid, butyl cellosolve acetic acid, ethyl acetic acid, methyl acetic acid, isopropyl acetic acid, methyl cellosolve acetic acid, methyl ethyl ketone, acetone or mixtures thereof .

The solvent may be added in a proportion of 10 to 200 parts by weight based on 100 parts by weight of the epoxy resin. The content of the solvent may be adjusted to control the application and workability.

In the present invention, a surface protective coating layer may be formed on a metal structure by coating the surface of the metal structure with a coating composition for protecting a metal surface, and then curing the coating.

To this end, the coating composition for protecting a metal surface may be prepared in a liquid form such as a coating material and may be applied to the surface of a metal structure such as a spray coating, a dip coating, a gravure coating, a brushing or the like The coating composition can be coated using a conventional method and cured at 20 to 40 ° C, that is, at room temperature for 12 to 60 hours to form a surface protective coating layer on the metal structure. Such a coating composition for protecting a metal surface can improve adhesion and weatherability It is possible to form a surface protective coating layer having an excellent bonding strength without using a primer polymer used for strengthening the adhesive layer.

The surface protective coating layer formed by the above method may be coated with a coating composition for protecting a metal surface to have an average thickness of 0.01 to 10 mm. When the thickness of the surface protective coating layer is less than 0.01 mm, the surface protective effect of the metal structure is reduced There is a problem that mechanical strength may be lowered when the thickness is formed to a thickness exceeding 10 mm. Preferably, the surface protective coating layer may have a thickness of 0.05 to 3 mm.

The metal structure may include both a tubular structure and a plate-like structure manufactured using materials such as iron metal and non-ferrous metal, and the metal structure may be coated with a coating composition for protecting a metal surface after the surface is pretreated .

Specifically, a metal structure is usually manufactured by heating to a high temperature and then shaping the metal structure to have a plate shape or a tubular shape. The metal structure manufactured by such a method is shrunk during the cooling process, Micro cracks such as cracks and pin holes are generated. As described above, the microstructured metal structure has a rough surface, microbes easily adhere and propagate between cracks, scale and foreign matter are generated, and corrosion resistance is lowered.

In order to maximize the attractive force of the molecules at the interface of the dissimilar materials and to enhance the bonding force, the adhesion force between the metal surface protective coating composition and the metal structure, which will be described later, It is preferable to coat the coating composition for protecting the surface of metal with the foreign matters completely removed.

Accordingly, in the present invention, it is possible to further include a step of pretreating the metal structure as described above before coating the coating composition for protecting a metal surface. The metal structure may be pretreated to remove foreign substances and fine cracks remaining on the surface, It is possible to remove scales or foreign substances which are defective elements that inhibit the formation of the protective coating layer.

Typical examples of the pretreatment include an etching method using an acid corrosion, an electrochemical treatment, a sandblasting, a brushing, a silicon coating, a primer coating, or a mixture thereof. A cleaning method may be used in which the surface of the metal structure is cleaned with a cleaning agent containing an activator and an abrasive.

Preferably, the pretreatment can be carried out by a sand blasting method using a metal powder, an organic acid, an inorganic acid, a chelating agent or a mixture thereof, more preferably an aluminum oxide powder having an average particle size of 100 to 500 μm (Al ₂ O ₃ powder), and controlling the pressure for spraying the powder and the treatment time.

In the present invention, in order to further improve the adhesive strength and physical properties of the surface protective coating layer formed on the surface of the metal structure subjected to the first pre-treatment before coating the metal surface protective coating composition, the metal structure is subjected to a first pre- And a second pre-treatment step of forming a primer layer on the surface by coating the primer composition on the structure.

The primer layer can improve the bonding force with the rear surface protective coating layer formed on the surface of the metal structure by using the primer composition having excellent compatibility with the epoxy resin and further enhance the properties such as corrosion resistance, Any primer composition having excellent compatibility can be used without limitation.

For example, the primer composition may include 100 parts by weight of an epoxy resin, 20 to 50 parts by weight of a silicone resin, and 5 to 30 parts by weight of a filler.

The epoxy resin contained in the primer composition may include a bisphenol F type epoxy resin having an epoxy equivalent of 100 to 200, and the bisphenol F type epoxy resin is excellent in workability and flow resistance, and has excellent adhesiveness, chemical resistance, And so on.

The silicone resin contained in the primer composition serves to form a primer layer having excellent stain resistance, weather resistance, heat resistance, flame retardancy, electrical properties, water repellency and the like, excellent mechanical properties, and can be easily cured at room temperature, Organopolysiloxanes, organopolysiloxanes, or mixtures thereof.

The primer composition may contain 20 to 50 parts by weight of the silicone resin based on 100 parts by weight of the epoxy resin. When the content of the silicone resin is less than 20 parts by weight, it is difficult to impart sufficient physical properties to the primer layer. There is a possibility that the workability is lowered.

The filler contained in the primer composition serves to inhibit the occurrence of corrosion due to cracks or the like formed on the surface of the metal structure and inhibits the generation of corrosion. The filler contains talc, bentonite, feldspar, barium sulfate, silica, alumina hydroxide, titanium dioxide, calcium carbonate, Examples of the corrosion-resistant ceramic powder include magnesium, alumina, mica, wollastonite, and mixtures thereof. The filler may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the epoxy resin. When the content of the filler is less than 5 parts by weight, crack repair effect may not be large. When the filler is more than 30 parts by weight There may arise a problem that the primer composition is deteriorated in mechanical properties such as adhesion to a metal structure and durability.

The primer composition may include a solvent and may be mixed in a proportion of 5 to 200 parts by weight based on 100 parts by weight of the epoxy resin.

Further, the primer composition may further comprise additives such as a corrosion inhibitor, a defoamer, a thickener, a dispersant, an anti-flow agent, a deodorant, or a mixture thereof, and the additives may each contain 0.1 to 5 parts by weight, By weight based on the total weight of the composition.

According to a preferred embodiment of the present invention, the metal structure is preferably a steel pipe, and examples thereof include a ductile iron-made steel pipe, a general steel pipe, and the like.

Specifically, the cast iron pipe may include a conventional cast iron pipe manufactured using a base including pearlite, ferrite, or a mixture thereof, and may include graphite nodular elements such as magnesium and calcium to reinforce impact force and tensile force It may also include a ductile cast iron tube.

More preferably, the metal structure may be a ductile iron casting duct used as a sewer pipe, and the surface protective coating layer serves to prevent corrosion of the inner and outer surfaces of the ductile iron cast iron pipe.

The above-mentioned ductile iron casting tube was subjected to first preliminary treatment by sand blasting using aluminum oxide powder having an average particle size of 100 to 500 mu m, and then 100 parts by weight of bisphenol F type epoxy resin, 30 parts by weight of silicone resin, 10 parts by weight of talc And 20 parts by weight of isopropyl alcohol can be coated and cured for 36 to 72 hours to form a primer layer on the surface of the dendrite cast iron tube.

100 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent weight (g / eq) of 450, 15 parts by weight of an acrylic resin, 30 parts by weight of a polyester resin, 15 parts by weight of a trimethylhexamethylenediamine curing agent 15 10 parts by weight of 2- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, 30 parts by weight of basalt fiber, 5 parts by weight of bismuth vanadate, and 1 part by weight of a dispersing agent, And then cured for 36 to 48 hours to form a surface protective coating layer on the surface of the dendrite cast iron pipe. Such a surface protective coating layer has excellent physical properties and is not peeled off for a long time, .

According to the method for manufacturing a metal structure according to the present invention as described above, the corrosion resistance, the water resistance and the water resistance of the metal structure can be improved by a simple method of coating the surface of the metal structure including the ferrous metal, The chemical resistance can be improved, and the surface protective coating layer can be stably prevented from changing the physical properties of the metal structure for a long period of time.

Hereinafter, the present invention will be described in more detail with reference to examples.

The embodiments presented are only a concrete example of the present invention and are not intended to limit the scope of the present invention.

≪ Example 1 >

1 is a process drawing showing a process for manufacturing a metal structure (ductile iron casting tube) having a surface protective coating layer formed by the method according to the second embodiment.

First, a commercially available ductile iron casting tube (length 12 cm, diameter 7.5 cm, thickness 2.5 mm) was purchased and used as a metal structure specimen. The outer and inner surfaces of the specimen were coated with aluminum oxide powder having an average particle size of 100 to 500 μm The sandblasting method was used for the first pretreatment.

A primer composition comprising 100 parts by weight of a bisphenol F type epoxy resin, 30 parts by weight of a silicone resin, 15 parts by weight of an amine-based curing agent, 10 parts by weight of a filler and 20 parts by weight of isopropyl alcohol was coated on the surface of a pre- And then cured for the next 48 hours to form a primer layer having a dry film thickness of 40 to 50 mu m on the surface.

100 parts by weight of a bisphenol A type epoxy resin having an epoxy equivalent weight (g / eq) of 450, 15 parts by weight of an acrylic resin, 30 parts by weight of a polyester resin, 15 parts by weight of a trimethylhexamethylenediamine curing agent, 10 parts by weight of 2- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, 30 parts by weight of basalt fiber, 5 parts by weight of bismuth vanadate and 1 part by weight of a dispersing agent were coated, For a period of time to form a surface protective coating layer having a dry coating thickness of 340 to 350 占 퐉 on the surface of a dull tile cast iron pipe.

The basalt fiber was 3 mm in length and 5 m in diameter, and the basalt staple fibers were immersed in a 70% sulfuric acid aqueous solution for 3 hours to modify the surface.

≪ Example 2 >

A surface protective coating layer having a dry coating thickness of 340 to 350 占 퐉 was formed on the surface of a dull tile cast iron pipe in the same manner as in Example 1, except that a primer layer was not formed.

≪ Example 3 >

A surface protective coating layer was formed on the surface of a dentile cast iron tube in the same manner as in Example 2, except that a coating composition for metal surface protection comprising 20 parts by weight of basalt fibers was used.

<Example 4>

A surface protective coating layer was formed on the surface of a dull tile cast iron tube in the same manner as in Example 2, except that a coating composition for metal surface protection comprising 50 parts by weight of basalt fibers was used.

&Lt; Comparative Example 1 &

A surface protective coating layer having a dry coating thickness of 200 to 50 占 퐉 was formed on the surface of a dull tile cast iron pipe in the same manner as in Example 2, except that a coating composition for protecting metal surfaces not containing a basalt fiber was used.

&Lt; Comparative Example 2 &

A surface protective coating layer was formed on the surface of a dull tile cast iron pipe in the same manner as in Example 2 except that a coating composition for protecting a metal surface including 10 parts by weight of basalt fibers was used.

&Lt; Comparative Example 3 &

A surface protective coating layer was formed on the surface of a ductile iron casting tube in the same manner as in Example 2, except that a coating composition for metal surface protection comprising 60 parts by weight of basalt fibers was used.

<Experimental Example>

The test was conducted according to the test standards specified in the American Waterworks Association (AWWA C 222-99) standard to evaluate the physical properties of the surface protective coating layer formed on the surface of the metal specimen by the methods according to Examples 1 to 4 and Comparative Examples 1 to 3 The results are shown in Table 1 below.

As shown in Table 1, the surface protective coating layers formed on the metal specimens according to the methods of Examples 1 to 4 have high adhesion strength, excellent impact resistance, abrasion resistance, shore hardness, and the like, And excellent chemical resistance such as acid resistance and salt resistance, and thus it can be confirmed that it can be used stably for a long period of time.

In particular, it was confirmed that the surface protective coating layer of Comparative Example 1 containing no basalt fiber as a fiber reinforcing agent had the lowest physical properties, and the surface protective coating layer formed by mixing the basalt fibers showed improved physical properties, From the measurement results, it was possible to calculate the optimal inclusion content of the basalt fiber as a fiber reinforcing agent.

According to the above results, when the method for manufacturing a metal structure according to the present invention is used, a surface protective coating layer having excellent physical properties can be formed on the surface of a metal structure. Such a method can be utilized for improving the physical properties of various metal structures I can confirm that I can.

Claims (5)

10 to 20 parts by weight of an epoxy resin, 10 to 20 parts by weight of an acrylic resin, 20 to 50 parts by weight of a polyester resin, 10 to 20 parts by weight of an amine curing agent, 5 to 20 parts by weight of a silane coupling agent, 50 to 50 parts by weight of a pigment and 1 to 20 parts by weight of a pigment is coated on the surface of a metal structure and then cured to form a surface protective coating layer,
Characterized in that the basalt fiber has a length of 0.01 to 10 mm and a diameter of 1 to 30 탆 and is modified to include a hydroxyl group (-OH) by immersion in an acidic solution for 2 to 5 hours. Way. The method according to claim 1,
The metal structure may be pretreated by one or more methods selected from the group consisting of etching, electrochemical treatment, sandblasting, brushing, silicon coating and primer coating using acid etching. Wherein the metal structure is made of a metal. The method according to claim 1,
Wherein the metal surface protective coating composition further comprises at least one additive selected from the group consisting of flow improvers, flow improvers, dispersants, antimicrobial agents, and ceramic fillers. delete 10 to 20 parts by weight of an epoxy resin, 10 to 20 parts by weight of an acrylic resin, 20 to 50 parts by weight of a polyester resin, 10 to 20 parts by weight of an amine curing agent, 5 to 20 parts by weight of a silane coupling agent, 50 parts by weight and 1 to 20 parts by weight of a pigment,
Wherein the basalt fiber is modified to have a length of 0.01 to 10 mm and a diameter of 1 to 30 탆 and immersed in an acidic solution for 2 to 5 hours to include hydroxyl groups (-OH) Composition.

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