KR20140040996A - Resin coated steel sheet and the resin composition for resin coated steel sheet - Google Patents

Abstract

The present invention relates to a resin coated steel sheet and primer and topcoat compositions for the same. The resin coated steel sheet and primer and topcoat compositions for the same according to the present invention is environmentally friendly; lowers production costs by eliminating the use of expensive raw materials; and has excellent appearance, blackness, lubricity, bending properties, corrosion resistance, and coating adhesion properties.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated steel sheet and a resin-

The present invention relates to a resin-coated steel sheet and a undercoating composition and a topcoat composition used for the resin-coated steel sheet.

In recent years, the interior and exterior materials of the above-mentioned interior and exterior materials have been rapidly replaced by steel thin plate materials from plastic injection materials that have been used in the past, due to competition for thinning of interior and exterior materials of household electric appliances such as PDP, LCD, and LED TV among home appliance companies. In particular, a resin-coated steel sheet such as a black resin steel plate having a beautiful and colored surface is applied to the exterior material so that the exterior material can be directly attached to the product after the press processing without additional coating process.

This resin-coated steel sheet can be applied to the exterior material immediately after the press without any additional coating process, and it is produced with a blackness level of 75 to 98, favoring black appearance (blackness = 100-L *, L * = whiteness) .

As shown in FIG. 1, the resin coated steel sheet is mainly composed of a top coat layer 1 such as a black resin layer expressing black, and a bottom coat layer 2 for tightly adhering the base steel sheet 3 and the top coat layer. have.

Although chromium has been mainly applied to the underlayer, environmental research organizations such as European EU RoHS have restricted the use of chromium by regulating chromium as a carcinogen. Therefore, there is a need to develop a chromium-free underlayer .

The resin-coated steel sheet is a product of a thick-film coating in which the thickness of the organic coating film such as the upper layer and the undercoat layer is mostly more than 25 μm.

In recent years, due to the demand for cost reduction and the demand for thinning of thin film, a thin film type black resin sheet having a thickness of 10 μm has been developed and supplied. However, there is a demand for cost reduction of users.

However, as the thickness of the undercoating layer becomes thinner, it is difficult to lower the cost by using an expensive raw material for manufacturing resin composition in order to satisfy adhesiveness and corrosion resistance.

An object of the present invention is to provide a resin-coated steel sheet which does not contain chromium and which is environmentally friendly but which does not use expensive raw materials and which is inexpensive and excellent in properties, and a undercoat composition and a topcoat composition used in the resin-coated steel sheet.

One aspect of the present invention relates to a base steel sheet, which is formed on the base steel sheet and includes 0.1 to 10% by weight of an aqueous dispersion phenolic resin, 0.5 to 5% by weight of a metal salt, 1 to 10% by weight of an inorganic acid, Wherein the base layer is formed on one side of the undercoating layer and comprises 10 to 80% by weight of a polyester resin, 1 to 45% by weight of a black pigment dispersion, 0.1 to 10% by weight of a wax, 5 to 50% by weight of a cross- % And a mixed solvent: 5 to 60% by weight, wherein the undercoat layer has an adhesion amount of 30 to 500 mg / m < 2 >, and the thickness of the steel sheet coated with the undercoat layer and the topcoat layer Coated steel sheet having a thickness of 1 to 25 mu m.

Another aspect of the present invention provides a primer composition for use in a resin sheet comprising 0.1 to 10% by weight of an aqueous dispersion phenolic resin, 0.5 to 5% by weight of a metal salt, 1 to 10% by weight of an inorganic acid, and the remainder.

In another aspect of the present invention, there is provided a polyester resin composition comprising 10 to 80 wt% of a polyester resin, 1 to 45 wt% of a black pigment dispersion, 0.1 to 10 wt% of a wax, 5 to 50 wt% of a crosslinking agent, By weight based on the total weight of the resin-coated steel sheet.

In addition, the solution of the above-mentioned problems does not list all the features of the present invention. The various features of the present invention and the advantages and effects thereof will be more fully understood by reference to the following specific embodiments.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a resin-coated steel sheet which is environmentally friendly but does not contain expensive raw materials and is inexpensive yet excellent in designability, blackness, lubricity, bending property, corrosion resistance and coating film adhesion, To provide a topical composition.

1 is a perspective view showing the structure of a resin-coated steel sheet as one aspect of the present invention.

The present inventors have conducted research to provide an ultra-thin film coated steel sheet excellent in corrosion resistance and high film strength without using expensive raw materials. As a result, it has been found that by controlling the composition and components of the upper layer and lower layer, It is possible to produce a resin-coated steel sheet having an ultra-thin undercoat layer simultaneously exhibiting excellent adhesion, lubricity, bending property, corrosion resistance and coating film adhesion.

One aspect of the present invention relates to a base steel sheet, which is formed on the base steel sheet and includes 0.1 to 10% by weight of an aqueous dispersion phenolic resin, 0.5 to 5% by weight of a metal salt, 1 to 10% by weight of an inorganic acid, Wherein the base layer is formed on one side of the undercoating layer and comprises 10 to 80% by weight of a polyester resin, 1 to 45% by weight of a black pigment dispersion, 0.1 to 10% by weight of a wax, 5 to 50% by weight of a cross- % And a mixed solvent: 5 to 60% by weight, wherein the undercoat layer has an adhesion amount of 30 to 500 mg / m < 2 >, and the thickness of the steel sheet coated with the undercoat layer and the topcoat layer Coated steel sheet having a thickness of 1 to 25 mu m.

In the present invention, the undercoating composition for forming an ultra-thin film layer having excellent economical efficiency due to low manufacturing cost and excellent corrosion resistance and coating film adhesion of the top layer and the resin steel sheet, comprises 0.1 to 10% by weight of an aqueous dispersion phenol resin, 0.5 to 5% , Inorganic acid: 1 to 10% by weight, and the remainder.

The water-dispersed phenolic resin is preferably included to improve corrosion resistance and film adhesion. The content thereof is preferably 0.1 to 10% by weight. When the water-dispersible phenol resin is contained in an amount of less than 0.1% by weight, the corrosion resistance and adhesion to the coating film are largely deteriorated. When it exceeds 10% by weight, the solution stability is lowered. More preferably from 0.5 to 5% by weight.

Examples of the functional group of the water-dispersible phenol resin include at least one kind selected from the group consisting of primary, secondary, tertiary and quaternary amine groups or halogen elements of fluorine, chlorine, bromine and iodine Do.

The metal salt is preferably included to improve corrosion resistance. The content thereof is preferably 0.5 to 5% by weight. When the metal salt is contained in an amount of less than 0.5% by weight, the corrosion resistance is deteriorated. When the metal salt is more than 5% by weight, bending properties are deteriorated. More preferably 1 to 3% by weight.

Non-limiting examples of the metal salt include magnesium sulfate, magnesium chloride, magnesium nitrate, magnesium acetate, vanadium sulfide, vanadium sulfate, vanadium chloride, manganese sulfate, manganese sulfide, manganese chloride, nickel sulfate, nickel chloride, It is preferably at least one of nickel sulfide, zinc chloride, zinc sulfate, zinc chloride, zinc acetate, zirconium phosphate, zirconium chloride, and acetate.

It is preferable that the inorganic acid is included in order to improve the film adhesion. The content thereof is preferably 1 to 10% by weight. When the amount of the inorganic acid is less than 1% by weight, the adhesion of the coating film is deteriorated. When the amount of the inorganic acid is more than 10% by weight, surface corrosion of the base steel sheet is caused. More preferably 1 to 5% by weight .

In addition, the remainder of the composition is water. By including a certain percentage of the water, viscosity control and solution stability of the undercoat layer can be ensured. That is, it is preferable that the undercoat composition is applied to a base steel sheet, dried and cured to form a subbing layer.

The adhesion amount of the undercoating layer adhering to the base steel sheet is preferably 30 to 500 mg / m 2. When the undercoating layer has an adhesion amount of less than 30 mg / m 2, there is a problem that the corrosion resistance is poor. When the undercoating layer has an adhesion amount exceeding 500 mg / m 2, there is a problem that bending property is weakened. Therefore, it is preferable that the undercoating layer has an adhesion amount of 30 to 500 mg / m < 2 >.

Further, in the present invention, the properties of the resin-coated steel sheet vary depending on the characteristics of the pigment, which is influenced by the composition of the upper layer. In the present invention, a topcoat composition containing a black pigment, which is a preferred embodiment, is coated on a base steel sheet to form a top coat layer to produce a resin-coated steel sheet. That is, it is preferable that the top coat composition is applied to the primer layer, dried and cured to form the top layer.

The top coat composition for forming the top coat layer comprises 10 to 80% by weight of a polyester resin, 1 to 45% by weight of a black pigment dispersion, 0.1 to 10% by weight of a wax, 5 to 50% by weight of a cross- To 60% by weight.

The polyester resin is preferably included to improve the corrosion resistance and the bending property. And the content thereof is preferably 10 to 80% by weight. When the content of the polyester resin is less than 10% by weight, the corrosion resistance and bending property are deteriorated. When the content is more than 80% by weight, the lubricity and design property are deteriorated. More preferably 10 to 50% by weight.

The acid value of the polyester resin is preferably 5 mgKOH / g or less. If the acid value of the polyester resin exceeds 5 mgKOH / g, the corrosion resistance and bending properties are deteriorated. In addition, the base resin of the polyester resin is preferably 5 mgKOH / g to 20 mgKOH / g. When the base of the polyester resin is less than 5 mgKOH / g, the solution stability is deteriorated. When the base resin exceeds 20 mgKOH / g, the corrosion resistance is lowered.

The average molecular weight of the polyester resin is preferably 20,000 to 50,000. When the average molecular weight is less than 20,000, the corrosion resistance is deteriorated. When the average molecular weight is more than 50,000, the solution stability is deteriorated.

The polyester resin preferably contains 20 to 60 mol% of the monomer of the acid component and 20 to 40 mol% of the polyhydric alcohol.

When the acid monomer is added in an amount of less than 20 mol%, the corrosion resistance of the present invention can not be secured. When the acid monomer is added in an amount of more than 60 mol%, bending properties are lowered.

At this time, it is preferable that the monomer of the acid component includes 20 to 60 mol% of aromatic acid component, 5 to 40 mol% of aliphatic acid component, and 1 to 30 mol% of alicyclic acid component.

When the aromatic acid component is contained in an amount of less than 20 mol%, the corrosion resistance is deteriorated. When the aromatic acid component is added in an amount exceeding 60 mol%, the bending property is deteriorated. Further, as the non-limiting examples of the aromatic acid component, at least one of phthalic anhydride, terephthalic acid and isophthalic acid is preferable.

When the aliphatic acid component is contained in an amount of less than 5 mol%, the bending property of the present invention can not be ensured. When the aliphatic acid component is added in an amount exceeding 40 mol%, the corrosion resistance is deteriorated. Non-limiting examples of the aliphatic acid component include at least one of adipic acid, succinic acid, azelaic acid, and sebacic acid.

When the alicyclic acid component is contained in an amount of less than 1 mol% or in an amount of more than 30 mol%, the corrosion resistance or bending property is deteriorated. Non-limiting examples of the alicyclic acid component include at least one of 1,4-cyclohexane dicarboxylic acid, hexahydrophthalic anhydride, and tetrahydrophthalic anhydride.

When the content of the polyhydric alcohol is less than 20 mol%, the bending property is deteriorated. When the polyhydric alcohol is contained in an amount exceeding 40 mol%, the corrosion resistance is deteriorated.

Non-limiting examples of the polyhydric alcohol include 1,4-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,6-hexanediol, propylene glycol, diethylene glycol, , Neopentyl glycol, and 1,4-cyclohexane anhydride.

The polyhydric alcohol preferably comprises 30 to 60 mol% of ethylene oxide and 4 to 6 mol% of bisphenol A.

When the ethylene oxide is contained in an amount of less than 30 mol% and in an amount of more than 60 mol%, the corrosion resistance or bending property is deteriorated.

At this time, the content ratio of ethylene oxide to bisphenol A is not particularly limited, but preferably 4 to 6 mols of ethylene oxide per 1 mole of bisphenol A is preferably polymerized. When the ethylene oxide is polymerized at less than 4 moles per mole of bisphenol A, the bending property is insufficient. When the ethylene oxide is polymerized at more than 6 moles, the corrosion resistance is lowered.

In the present invention, a black pigment dispersion is included to ensure high blackness and decorative properties.

If the black pigment dispersion is contained in an amount of less than 1% by weight, the blackness and decorative properties are lowered. On the other hand, when the black pigment dispersion exceeds 45% by weight, corrosion resistance and film adhesion are lowered. Therefore, the black pigment dispersion is preferably contained in an amount of 1 to 45% by weight. More preferably 10 to 30% by weight.

In addition, the black pigment dispersion which can be used in the present invention is preferably composed of the above-mentioned polyester resin, black pigment and dispersion stabilizer.

The black pigment dispersion may contain 10 to 95% by weight of a polyester resin, 5 to 25% by weight of a black pigment, and 0.1 to 15% by weight of a dispersion stabilizer.

If the amount of the polyester resin is less than 10% by weight, solution stability and designability may be lowered. On the other hand, when it exceeds 95% by weight, the blackness and designability are lowered.

In addition, it is difficult for black pigments to achieve proper dispersion stability through direct stirring in a solution, and a non-uniform dispersion state is difficult to realize the appropriate blackness of the pigment. Therefore, for easy dispersion, it is preferable to include a dispersion process of density called milling in place of ordinary solution stirring. The black pigment particles are preferably dispersed in a polyester resin. However, since dispersion is not sufficient in this state, it is preferable to further use 0.1 to 15% by weight of a dispersion stabilizer.

As the non-limiting examples of the black pigment particles usable in the present invention, at least one of carbon nanotubes (CNTs), carbon fibers, carbon black (CB), graphite and graphene can be selected .

In the present invention, wax is included to improve lubricity.

When the wax is less than 0.1% by weight, the lubricity to be obtained in the present invention can not be ensured. When the wax is more than 10% by weight, the coating film adhesion is deteriorated. More preferably from 0.5 to 5% by weight.

Non-limiting examples of waxes that can be used in the present invention include Candelilla wax, Carnauba wax, Caster wax, Espalto wax, Ouerkyl wax, Bayberry wax, Jojoba wax, Rice bran wax, Wax, and synthetic waxes including paraffin wax, polyethylene wax, Fischer-Tropsch wax, amide wax, polypropylene wax, polyolefin wax, and modified waxes thereof.

In the present invention, a cross-linking agent is included to improve the curability.

If the crosslinking agent is less than 5% by weight, the curing may not be completed. If the crosslinking agent is more than 50% by weight, bending properties are insufficient due to overcuring. More preferably 5 to 35% by weight.

The crosslinking agent usable in the present invention may include at least one selected from a melamine crosslinking agent, an isocyanate crosslinking agent and an aziridine crosslinking agent.

The crosslinking agent usable in the present invention may be selected from at least one of a melamine crosslinking agent, an isocyanate crosslinking agent and an aziridine crosslinking agent.

In addition, the present invention includes a mixed solvent in order to improve the fluidity of the paint and the defoaming force to ensure work stability and to minimize surface defects during rapid drying or rapid curing.

When the mixed solvent is contained in an amount of less than 5% by weight, designability is deteriorated, and when it exceeds 60% by weight, corrosion resistance is deteriorated. More preferably 10 to 50% by weight.

Also, the mixed solvent includes a first polymer material having a boiling point of 100 to 180 ° C and a second polymer material having a boiling point of 181 to 240 ° C.

At this time, the ratio of the first polymer material to the second polymer material is preferably 10: 1 to 1:10.

Preferably, the first polymer material is at least one of cyclohexane, sorbose 100, toluene, xylene, 1-methoxy-2-propanol, cyclohexanone and normal butanol, and the second polymer material is at least one selected from the group consisting of butyl carbitol , Di-basic ester, benzyl alcohol, ethyl benzoate, dimethylaniline, dimethyl sulfoxide, aniline, 1-octanol and 1-butanol.

In addition, additional elements such as an acid catalyst, a quencher and an adhesion promoter may be known to any person skilled in the art, so that it is preferable to selectively incorporate them into the top coat composition of the upper layer as required.

The coating composition can be used to form a coating layer on the surface of the steel sheet. The coating is not limited to any coating method, and any method can be used as long as it is a coating method. As a part of coating the solution on the steel sheet, a method commonly used in the technical field such as immersion, spraying and coating can be applied.

The thickness of the steel sheet coated with the undercoat layer and the upper layer including the above composition is preferably 1 to 25 mu m. When the thickness of the coating layer is less than 1 mu m, the designability and corrosion resistance of the surface treated steel sheet contemplated by the present invention can not be realized. On the other hand, when the thickness exceeds 25 mu m, the coating film adhesion and bending properties of the surface- .

Another aspect of the present invention provides a primer composition for use in a resin sheet comprising 0.1 to 10% by weight of an aqueous dispersion phenolic resin, 0.5 to 5% by weight of a metal salt, 1 to 10% by weight of an inorganic acid, and the remainder.

In another aspect of the present invention, there is provided a polyester resin composition comprising 10 to 80 wt% of a polyester resin, 1 to 45 wt% of a black pigment dispersion, 0.1 to 10 wt% of a wax, 5 to 50 wt% of a crosslinking agent, By weight based on the total weight of the resin-coated steel sheet.

Hereinafter, the present invention will be described more specifically by way of examples. It should be noted, however, that the following examples are intended to illustrate the invention in more detail and not to limit the scope of the invention. The scope of the present invention is determined by the matters set forth in the claims and the matters reasonably inferred therefrom.

(Example 1)

The compositions having composition and composition ranges as shown in the following Tables 1 and 2 were stirred at room temperature to prepare undercoat compositions.

The polyester resin in the upper layer composition was prepared by adding 40 mol of a compound obtained by subjecting 30 mol% of isophthalic acid, 10 mol% of adipic acid, 10 mol% of 1,4-cyclohexanedicarboxylic acid, 1 mol of bisphenol A and 4 mol of ethylene oxide %, And 10 mol% of 1,4-butylene glycol were put into a round flask and reacted at 115 ° C with passing nitrogen. At this time, the produced polyester resin had an acid value of 2.5 mgKOH / g, a base of 15.0 mgKOH / g, and a weight average molecular weight of 22,450

The mixed solvent in the top layer composition was prepared by mixing Solvesso 100 and the second polymer material group cyclohexanone in a ratio of 1: 1 as the first polymer substance group.

The black pigment dispersion in the top layer composition was composed of 35% by weight of the polyester resin prepared above, 15% by weight of dispersion stabilizer Lubrizol, Solsperse 32600, 10% by weight of carbon black N 500 (Korea Carbon Black, Alumina balls were added to 40 wt% of the prepared mixed solvent, and the mixture was operated in a ball mill at 3000 rpm for 10 minutes.

A black pigment dispersion was prepared by mixing 40 wt% of the polyester resin, 17 wt% of a black pigment dispersion, 5 wt% of a curing agent (Cymel 325), 0.5 wt% of wax (Lubrizol, Lanco ™ Glidd 4832) (Evonik Degussa, Aerosil R 7200) 2 wt%, 1 wt.% Of an antioxidant (EFKA, EFKA-2720), 0.5 wt.% Of an acid catalyst (King industry, Nacure 1051) By weight, and 31% by weight of a mixed solvent were stirred at room temperature to prepare a top layer composition.

division Water Dispersed Phenolic Resin Metal salt Inorganic acid Water content (%) Type of functional group content(%) Kinds content(%) Kinds content(%) Kinds content(%) Inventory 1 Methylamine 3.5

Magnesium acetate 3.7 Phosphoric Acid 1.4 Hexafluorozirconic acid 2.8 88.5 Inventive Example 2 Fluorine 4.8

Vanadium sulfate 1.3 Phosphoric Acid 0.9 Hexafluorozirconic acid 2.0 91.0 Inventory 3 Fluorine 9.2

Magnesium sulfate 2.1 Silicic acid 0.6 Hexafluorotitanic acid 4.7 83.4 Honorable 4 Propylamine 1.5

Zinc acetate 1.6 Phosphoric Acid 5.0 Hexafluorozirconic acid 2.6 89.4 Inventory 5 Dimethylamine 0.8

Zirconium acetate 3.2 Phosphoric Acid 4.8 Hexafluorotitanic acid 5.0 86.2 Inventory 6 Goat 2.2

Magnesium phosphate 3.5 Silicic acid 1.5 Hexafluorotitanic acid 5.0 87.8 Honorable 7 Trimethylamine 3.5

Manganese (II) sulfate 1.5 Phosphoric Acid 1.1 Hexafluorozirconic acid 1.0 92.9 Honors 8 bromine 5.5 Magnesium sulfate, vanadium sulfate (1: 1) 1.3 Phosphoric Acid 4.9 Hexafluorozirconic acid 2.9 85.3 Proposition 9 Arylamine 7.6

Magnesium nitrate 3.7 Phosphoric Acid 2.0 Hexafluorotitanic acid 4.7 81.9 Inventory 10 iodine 9.1

Vanadium chloride 3.4 Silicic acid 3.6 Hexafluorozirconic acid 0.9 83.0 Exhibit 11 Trimethylamine 1.9

Zinc phosphate 0.8 Phosphoric Acid 3.0 Hexafluorozirconic acid 4.4 89.9 Inventory 12 bromine 3.8 Vanadium chloride, zinc chloride (1: 1) 4.6 Silicic acid 3.0 Hexafluorotitanic acid 0.5 88.0 Inventory 13 Goat 2.8

Magnesium chloride 4.7 Silicic acid 4.0 Hexafluorozirconic acid 0.6 87.9 Inventory 14 Propylamine 6.1

Vanadium sulfate 4.8 Silicic acid 4.9 Hexafluorotitanic acid 1.5 82.8 Honorable Mention 15 Dimethylamine 3.5

Zirconium chloride 4.2 Phosphoric Acid 2.5 Hexafluorozirconic acid 4.3 85.4 Inventory 16 iodine 9.3

Magnesium sulfate 4.5 Silicic acid 2.0 Hexafluorozirconic acid 4.5 79.6 Inventory 17 Fluorine 8.1

Zinc nitrate 3.2 Silicic acid 3.3 Hexafluorotitanic acid 1.2 84.2 Inventory 18 Methylamine 7.8

Vanadium sulfate 3.0 Silicic acid 2.3 Hexafluorozirconic acid 1.7 85.2 Inventive Example 19 Goat 6.9

Zinc chloride 4.2 Phosphoric Acid 1.9 Hexafluorotitanic acid 4.0 83.1 Inventory 20 bromine 4.1

Magnesium sulfate 2.5 Silicic acid 0.6 Hexafluorozirconic acid 4.5 88.3

division Water Dispersed Phenolic Resin Metal salt Inorganic acid Water content (%) Type of functional group content(%) Kinds content(%) Kinds content(%) Kinds content(%) Comparative Example 1 Trimethylamine 1.4

Sodium chloride 2.1 Phosphoric Acid 3.5 Hexafluorozirconic acid 2.3 90.7 Comparative Example 2 Phenyl 6.1

Magnesium acetate 4.4 Phosphoric Acid 2.3 Hexafluorozirconic acid 1.4 85.8 Comparative Example 3 Propylamine 5.0

Vanadium sulfate 1.2 - - Hexafluorotitanic acid 0.5 93.3 Comparative Example 4 Dimethylamine 0.7

Zirconium chloride 4.2 Phosphoric Acid 14.4 - - 80.7 Comparative Example 5 benzyl 9.1

Vanadium sulfate 4.2 Phosphoric Acid 3.3 Hexafluorozirconic acid 1.8 81.8 Comparative Example 6 Goat 5.3

Potassium nitrate 4.9 Phosphoric Acid 3.2 Hexafluorotitanic acid 1.3 85.2 Comparative Example 7 Propylamine 0.01

Zinc acetate 2.6 Phosphoric Acid 3.5 Hexafluorozirconic acid 3.4 90.6 Comparative Example 8 bromine 1.1

- - Silicic acid 3.2 Hexafluorotitanic acid 3.6 92.2 Comparative Example 9 Goat 0.9

Magnesium chloride 3.5 Silicic acid 0.1 Hexafluorozirconic acid 0.1 95.4  Comparative Example 10 Methylamine 12.1

Zirconium acetate 1.7 Phosphoric Acid 2.4 Hexafluorotitanic acid 3.0 80.8  Comparative Example 11 bromine 9.0

Calcium sulfate 2.9 Phosphoric Acid 1.2 Hexafluorozirconic acid 4.7 82.2  Comparative Example 12 Trimethylamine 0.8

Zinc phosphate 6.7 Phosphoric Acid 1.8 Hexafluorozirconic acid 2.4 88.3 Comparative Example 13 iodine 4.8

Magnesium sulfate 3.7 Silicic acid 6.8 Hexafluorozirconic acid 8.4 76.2 Comparative Example 14 Goat 15.4

Magnesium phosphate 3.0 Silicic acid 4.5 Hexafluorotitanic acid 2.4 74.7 Comparative Example 15 iodine 0.9

Vanadium chloride 0.1 Silicic acid 2.2 Hexafluorozirconic acid 3.7 93.0 Comparative Example 16 profile 7.3

Magnesium sulfate 3.9 Silicic acid 1.6 Hexafluorotitanic acid 3.2 84.0

The composition of the subbing layer prepared in the above Table 1 and 2 was coated on an electrogalvanized steel sheet (steel sheet thickness: 1.0 mm) having a zinc adhesion amount of 20 g / m ² each using a roll coater, dried at 80 ° C, Was 56 mg / m < 2 >. The thus prepared steel sheet was coated with the composition of the prepared top layer using a roll coater, dried and cured at 240 ° C., and dried to prepare a resin-coated steel sheet having a thickness of 7 μm. The resin-coated steel sheet thus prepared was measured for corrosion resistance, film adhesion, bending property and solution stability according to the evaluation criteria described below, and the results are shown in Tables 3 and 4 below.

1) Corrosion resistance measurement

The prepared steel sheet was subjected to a salt water spray test according to JIS-Z2371 for 144 hours, and the degree of smell was evaluated according to the following criteria.

<Evaluation Criteria for Corrosion Resistance>

○: less than 5% of white rye

△: White rice 5% or more and less than 20%

×: 20% or more of white rust

2) Coating film adhesion measurement

The prepared steel sheet was cut into a size of 150 cm x 75 cm (width x length) to prepare specimens. The surfaces of the specimens were cut into 100 squares (width: 100 squares) at intervals of 1 mm using a cross cut guide And then a portion of the 100 columns was pushed up to a height of 6 mm using an erichsen tester and peeling tape (NB-1, manufactured by Ichiban Co., Ltd.) was applied to the pushed portion After attaching and detaching, it was observed whether or not the Ericsson part was peeled off.

&Lt; Evaluation Criteria of Coating Film Adhesion &

○: When there is no peeling of the surface

?: 1 to 3 of 100 peelings on the surface

X: When the peeling of the surface exceeds 3 out of 100

3) Bending property measurement

The bending properties of the prepared steel sheet were evaluated by coating the self-healing coating composition and 0 T banding after curing and observing the folded surface enlarged and evaluated according to the following criteria.

&Lt; Bending property evaluation standard &

○: 0%, 10%, 20% 0T banding and taping peeling after stretching are all clean without any cracks

△: There is no cracking at 0 T banding and taping peeling after 0% tensile, but 0 T after tensile and 20% tensile peeling, and partial cracking is visible at taping peeling.

X: 0%, 10%, 20% When 0T banding or taping peeling is performed after tensile, a partial crack or peeling of the entire film occurs

4) Solution stability

Immediately after the self-healing coating composition prepared by the above method was prepared, the initial viscosity (Vi) was measured, and after cooling to 25 ° C, the late viscosity (Vl) at 25 ° C was measured, And the results were evaluated according to the following evaluation criteria.

[Equation 1]

? V = (Vi-Vi) / Vi x 100 (%)

<Evaluation Criteria for Solution Stability>

∘: ΔV is less than 20 (%) or gelation phenomenon is not observed by visual observation

占 V: ΔV is 20 (%) or more, or gelation phenomenon is observed upon visual observation

division Corrosion resistance Coating film adhesion Bending ability Solution stability Inventory 1 O O O O Inventive Example 2 O O O O Inventory 3 O O O O Honorable 4 O O O O Inventory 5 O O O O Inventory 6 O O O O Honorable 7 O O O O Honors 8 O O O O Proposition 9 O O O O  Inventory 10 O O O O Exhibit 11 O O O O Inventory 12 O O O O Inventory 13 O O O O Inventory 14 O O O O Honorable Mention 15 O O O O Inventory 16 O O O O Inventory 17 O O O O Inventory 18 O O O O Inventive Example 19 O O O O Inventory 20 O O O O

division Corrosion resistance Coating film adhesion Bending ability Solution stability Comparative Example 1 X O X O Comparative Example 2 X X X O Comparative Example 3 X O X O Comparative Example 4 X O O X Comparative Example 5 X X X O Comparative Example 6 X O X O Comparative Example 7 X X O O Comparative Example 8 X O X O Comparative Example 9 X X O O  Comparative Example 10 X X X O  Comparative Example 11 X O X O  Comparative Example 12 X O X O Comparative Example 13 X O X X Comparative Example 14 X X O O Comparative Example 15 X O X O Comparative Example 16 X X X O

As shown in Table 3, Examples 1 to 20 show that the undercoat layer is formed with the undercoating composition satisfying the range proposed by the present invention, thereby exhibiting excellent corrosion resistance, film adhesion, bending property and solution stability.

On the other hand, as shown in Table 4, Comparative Examples 1 to 16 had a composition of a subbing layer which did not satisfy the range proposed by the present invention, so that at least two physical properties of corrosion resistance, film adhesion, bending property and solution stability We can confirm that it is bad.

(Example 2)

The undercoat composition of the subbing layer was prepared in the same manner as in Inventive Example 1 of the above-mentioned Example 1. [

The polyester resin in the composition of the upper layer was prepared by putting a composition having the composition and composition ranges shown in Tables 5 and 6 below into a round flask, passing nitrogen through it, and reacting at 115 ° C.

The mixed solvent in the top layer composition was prepared by mixing Solvesso 100 and the second polymer material group cyclohexanone in a ratio of 1: 1 as the first polymer substance group.

The black pigment dispersion in the top layer composition was composed of 35% by weight of the polyester resin prepared above, 15% by weight of dispersion stabilizer Lubrizol, Solsperse 32600, 10% by weight of carbon black N 500 (Korea Carbon Black, Alumina balls were added to 40 wt% of the prepared mixed solvent, and the mixture was operated in a ball mill at 3000 rpm for 10 minutes.

A black pigment dispersion was prepared by mixing 40 wt% of the polyester resin, 17 wt% of a black pigment dispersion, 5 wt% of a curing agent (Cymel 325), 0.5 wt% of wax (Lubrizol, Lanco ™ Glidd 4832) (Evonik Degussa, Aerosil R 7200) 2 weight%, 1 wt.% Of an antioxidant (EFKA, EFKA-2720), 0.5 wt.% Of an acid catalyst (King industry, Nacure 1051) By weight, and 31% by weight of a mixed solvent were stirred at room temperature to prepare a top layer composition.

division A B C D E Kinds mole% Kinds mole% Kinds mole% Ethylene oxide: bisphenol A ratio mole% Kinds mole% Inventory 21 Isophthalic acid 30


Adipic acid 10 1,4-cyclohexane dicarboxylic acid 10 4: 1 40 1,4-butylene glycol 10 Inventory 22 Isophthalic acid 30


Azelaixan 15 Tetrahydrophthalic anhydride 5 6: 1 40 1,3-butylene glycol 10 Inventive Example 23 Isophthalic acid 28


Sebacic acid 15 Tetrahydrophthalic anhydride 7 4: 1 30 2,3-butylene glycol 20 Honors 24 Isophthalic acid 20


Shoshinic acid 15 Hexahydrophthalic anhydride 15 5: 1 35 1,6-hexanediol 15 Honors 25 Isophthalic acid 30


Azelaixan 7 Hexahydrophthalic anhydride 13 5: 1 35 Propylene glycol 15 Evidence 26 Terephthalic acid 35


Shoshinic acid 5 Hexahydrophthalic anhydride 10 5: 1 40 Diethylene glycol 10 Inventive Example 27 Terephthalic acid 32


Azelaixan 13 1,4-cyclohexane dicarboxylic acid 5 5: 1 40 Neopentyl glycol 10 Evidence 28 Terephthalic acid 23


Shoshinic acid 20 1,4-cyclohexane dicarboxylic acid 7 4: 1 30 1,4-cyclohexane anhydride 20 Evidence 29 Terephthalic acid 25 Adipic acid 13 Tetrahydrophthalic anhydride 12 4: 1 30 Neopentyl glycol 20 Inventory 30 Terephthalic acid 25


Adipic acid 13 1,4-cyclohexane dicarboxylic acid 12 5: 1 30 1,4-butylene glycol 20 PROPERTIES 31 Phthalic anhydride 23 Sebacic acid 15 Tetrahydrophthalic anhydride 12 5: 1 40 1,3-butylene glycol 10 Exhibit 32 Phthalic anhydride 25 Azelaixan 15 Hexahydrophthalic anhydride 10 6: 1 35 2,3-butylene glycol 15 PROPERTIES 33 Phthalic anhydride 30 Shoshinic acid 10 Hexahydrophthalic anhydride 10 6: 1 40 1,6-hexanediol 10 PROPOSITION 34 Phthalic anhydride 23


Adipic acid 15 1,4-cyclohexane dicarboxylic acid 12 4: 1 30 Propylene glycol 20 Practice 35 Phthalic anhydride 33 Azelaixan 5 Hexahydrophthalic anhydride 12 4: 1 35 Diethylene glycol 15 EXPERIENCE 36 Phthalic anhydride 30 Azelaixan 11 Tetrahydrophthalic anhydride 9 6: 1 35 1,4-cyclohexane anhydride 15 A: aromatic acid component B: aliphatic acid component C: alicyclic acid component D: ethylene oxide addition bisphenol A F: polyhydric alcohol

division A B C D E Kinds mole% Kinds mole% Kinds mole% Ethylene oxide: bisphenol A ratio mole% Kinds mole% Comparative Example 17 Isophthalic acid 10


Adipic acid 25 1,4-cyclohexane dicarboxylic acid 15 6: 1 35 1,4-butylene glycol 15 Comparative Example 18 Isophthalic acid 20 Sebacic acid 15 Tetrahydrophthalic anhydride 25 5: 1 20 1,3-butylene glycol 20 Comparative Example 19 Terephthalic acid 30


Shoshinic acid 3 Hexahydrophthalic anhydride 17 4: 1 40 2,3-butylene glycol 10 Comparative Example 20 Phthalic anhydride 30


Shoshinic acid 20 - 0 4: 1 35 1,6-hexanediol 15 Comparative Example 21 Phthalic anhydride 25


Azelaixan 15 Hexahydrophthalic anhydride 10 5: 1 25 Propylene glycol 25 Comparative Example 22 Terephthalic acid 35 Adipic acid 10 Tetrahydrophthalic anhydride 5 2: 1 30 Diethylene glycol 20 Comparative Example 23 Phthalic anhydride 5 Azelaixan 35 Tetrahydrophthalic anhydride 20 5; 1 30 1,3-butylene glycol 10 Comparative Example 24 Terephthalic acid 20


Adipic acid 5 Hexahydrophthalic anhydride 35 5: 1 30 2,3-butylene glycol 10 Comparative Example 25 Isophthalic acid 25 Sebacic acid One Tetrahydrophthalic anhydride 34 4: 1 30 1,4-butylene glycol 10 A: aromatic acid component B: aliphatic acid component C: alicyclic acid component D: ethylene oxide addition bisphenol A F: polyhydric alcohol

The composition of the undercoat layer prepared above was coated on an electrogalvanized steel sheet (steel sheet thickness: 1.0 mm) having a zinc adhesion amount of 20 g / m ² each using a roll coater, dried at 80 ° C, . The thus prepared steel sheet was coated with the composition of the prepared top layer using a roll coater, dried and cured at 240 ° C., and dried to prepare a resin-coated steel sheet having a thickness of 7 μm. The resin-coated steel sheet thus prepared was measured for corrosion resistance, film adhesion, bending property and solution stability according to the evaluation criteria described below, and the results are shown in Tables 7 and 8 below.

5) Measurement of lubricity

The surface friction coefficient was measured using a UMT-2MT from CETR (Center for Tribology Inc.) USA and evaluated according to the following criteria.

<Lubricity Evaluation Standard>

?: Friction coefficient (占 퐉) Less than 0.25

?: Friction coefficient (占 퐉)? 0.25 or more and less than 0.4

X: Friction coefficient (占 퐉) 0.4 or more

The remainder, the bending property, the film adhesion, and the corrosion resistance are evaluated by the evaluation method described in the above-mentioned first embodiment.

division Bending ability Coating film adhesion Corrosion resistance Lubricity Inventory 21 O O O O Inventory 22 O O O O Inventive Example 23 O O O O Honors 24 O O O O Honors 25 O O O O Evidence 26 O O O O Inventive Example 27 O O O O Evidence 28 O O O O Evidence 29 O O O O Inventory 30 O O O O PROPERTIES 31 O O O O Exhibit 32 O O O O PROPERTIES 33 O O O O PROPOSITION 34 O O O O Practice 35 O O O O EXPERIENCE 36 O O O O

division Bending ability Coating film adhesion Corrosion resistance Lubricity Comparative Example 17 X X X X Comparative Example 18 O X X O Comparative Example 19 X O X X Comparative Example 20 X X X X Comparative Example 21 O X X X Comparative Example 22 X X O X Comparative Example 23 X X X O Comparative Example 24 X X X X Comparative Example 25 X X O X

As shown in Table 7, Inventive Examples 21 to 36 confirm that the polyester resin is contained in the composition of the upper layer which satisfies the range proposed by the present invention, thereby being excellent in bending property, film adhesion, corrosion resistance and lubricity .

On the other hand, as shown in Table 8, Comparative Examples 17 to 25 were obtained by coating a steel sheet with a polyester resin which does not satisfy the range proposed by the present invention, and it was confirmed that at least two of bending property, film adhesion, corrosion resistance, It can be confirmed that the physical properties are poor.

(Example 3)

The undercoat composition of the subbing layer was prepared in the same manner as in Inventive Example 1 of the above-mentioned Example 1. [

Compositions of top layers having compositions and composition ranges as shown in Tables 9 and 10 below were prepared.

At this time, the black pigment dispersion as the composition of the upper layer was composed of 35 wt% of polyester resin, 15 wt% of dispersion stabilizer Lubrizol, Solsperse 32600, 10 wt% of carbon black N 500 (Korea Carbon Black, Aluminum balls were added to 40 wt% of the mixed solvent, and the mixture was then operated in a ball mill at 3000 rpm for 10 minutes.

division Polyester
Polymer resin Mixed solvent Pigment
Dispersion
content(%) Wax
content(%) Cross-linking agent
content(%) content(%) Weight average
Molecular Weight A B A: B ratio content(%) Kinds Kinds Comparative Example 26 40 40,000 Cyclohexanone

- 10: 0 30 12 8 10.0 Comparative Example 27 40 80,000 Normal butanol

1-octanol 4: 6 35 9 3 13.0 Comparative Example 28 8 45,000 1-methoxy-2-propanol

Benzyl alcohol 2: 8 55 20 8 9.0 Comparative Example 29 30 20,000 Cyclohexane

Ethyl benzoate 7: 3 53 9 5 3.0 Comparative Example 30 45 30,000 Dimethyl phthalate

benzene 4: 6 35 4 4 12.0 Comparative Example 31 55 25,000 Cyclohexanone

Benzyl alcohol 8: 2 2 25 6 12.0 Comparative Example 32 48 38,000 1-methoxy-2-propanol

Butyl carbitol 5: 5 35 0.1 7.9 9 Comparative Example 33 50 44,000 Normal butanol

Ethyl benzoate 6: 4 12 13 15 10

The composition of the undercoat layer prepared above was coated on an electrogalvanized steel sheet (steel sheet thickness: 1.0 mm) having a zinc adhesion amount of 20 g / m ² each using a roll coater, dried at 80 ° C, . The thus prepared steel sheet was coated with the composition of the prepared top layer using a roll coater, dried and cured at 240 ° C., and dried to prepare a resin-coated steel sheet having a thickness of 7 μm. The bending resistance, film adhesion, corrosion resistance, lubricity, designability and blackness of the resin-coated steel sheet thus prepared were measured according to the evaluation criteria described below, and the results are shown in Tables 11 and 12 below.

6) Design measurement

After curing of the prepared steel sheet, surface defects were visually observed with a microscope and evaluated according to the following criteria.

<Evaluation criteria for design>

○: When there is no obvious defect when observing 10 times magnification with naked eye and microscope

△: There is no obvious defect when observing with the naked eye, but when observed with magnification 10 times under a microscope, when color change or partial peeling is observed

X: When a clear defect is observed when observing with the naked eye

7) Blackness measurement

The L-coordinate value (whiteness value) of the steel sheet was measured using a Lab colorimeter (ColorEye XTH, GretagMacbeth Co., Ltd.), and the blackness was evaluated according to the following evaluation criteria.

<Evaluation Criteria of Blackness>

?: When the L coordinate value of the surface-treated steel sheet is 26 or less

X: When the L coordinate value of the surface-treated steel sheet exceeds 26

The remainder, the bending property, the film adhesion, the corrosion resistance and the lubricity, are the evaluation methods described in the above-described first and second embodiments.

division Bending ability Coating film adhesion Corrosion resistance Lubricity Designability Blackness Honors 37 O O O O O O Honors 38 O O O O O O EVENTS 39 O O O O O O Honors 40 O O O O O O Inventory 41 O O O O O O Honors 42 O O O O O O Honors 43 O O O O O O Honors 44 O O O O O O Opportunity 45 O O O O O O

division Bending ability Coating film adhesion Corrosion resistance Lubricity Designability Blackness Comparative Example 26 O O X O X X Comparative Example 27 X X X O X X Comparative Example 28 X X X O X X Comparative Example 29 X O X X O O Comparative Example 30 X X X X X O Comparative Example 31 O O X X X O Comparative Example 32 X O O O X X Comparative Example 33 X X X X X X

As shown in Table 11, Inventive Examples 37 to 45 have a composition of a top layer satisfying the range proposed by the present invention, thereby confirming that bending property, film adhesion, corrosion resistance, lubricity, designability and blackness are both excellent .

On the other hand, as shown in Table 12, Comparative Examples 26 to 33 were obtained by coating a steel sheet with a composition of a top coat layer which did not satisfy the range proposed by the present invention, so that at least two of the bending property, the film adhesion, It can be confirmed that the above physical properties are poor.

(Example 4)

The undercoat composition of the subbing layer was prepared in the same manner as in Inventive Example 1 of the above-mentioned Example 1. [

The polyester resin in the upper layer composition was prepared by adding 40 mol of a compound obtained by subjecting 30 mol% of isophthalic acid, 10 mol% of adipic acid, 10 mol% of 1,4-cyclohexanedicarboxylic acid, 1 mol of bisphenol A and 4 mol of ethylene oxide %, And 10 mol% of 1,4-butylene glycol were put into a round flask and reacted at 115 ° C with passing nitrogen. At this time, the produced polyester resin had an acid value of 2.5 mgKOH / g, a base of 15.0 mgKOH / g, and a weight average molecular weight of 22,450

The mixed solvent in the top layer composition was prepared by mixing Solvesso 100 and the second polymer material group cyclohexanone in a ratio of 1: 1 as the first polymer substance group.

The black pigment dispersion in the top layer composition was composed of 35% by weight of the polyester resin prepared above, 15% by weight of dispersion stabilizer Lubrizol, Solsperse 32600, 10% by weight of carbon black N 500 (Korea Carbon Black, Alumina balls were added to 40 wt% of the prepared mixed solvent, and the mixture was operated in a ball mill at 3000 rpm for 10 minutes.

A black pigment dispersion was prepared by mixing 40 wt% of the polyester resin, 17 wt% of a black pigment dispersion, 5 wt% of a curing agent (Cymel 325), 0.5 wt% of wax (Lubrizol, Lanco ™ Glidd 4832) (Evonik Degussa, Aerosil R 7200) 2 weight%, 1 wt.% Of an antioxidant (EFKA, EFKA-2720), 0.5 wt.% Of an acid catalyst (King industry, Nacure 1051) By weight, and 31% by weight of a mixed solvent were stirred at room temperature to prepare a top layer composition.

Thereafter, the composition of the undercoat layer prepared above was coated on an electrogalvanized steel sheet (steel sheet thickness: 1.0 mm) having a zinc adhesion amount of 20 g / m ² each using a roll coater, and the coating amount shown in the following Table 13 was applied, . The thus prepared steel sheet was coated with the composition of the prepared top layer using a roll coater to prepare a resin-coated steel sheet having a thickness as shown in Table 13, and then the steel sheet was coated with a resin-coated steel sheet having corrosion resistance, film adhesion, The results are shown in Table 14 below. The above properties are evaluated using the evaluation method described in the above-mentioned first to third embodiments.

division Undercoating (mg / m ² ) Top layer thickness (탆) division Undercoating (mg / m ² ) Top layer thickness (탆) Honors 46 56 10 Comparative Example 34 16 17 Honors 47 296 14 Comparative Example 35 402 32 Honors 48 74 8 Comparative Example 36 317 0.4 Honorable 49 363 21 Comparative Example 37 21 4 Honors 50 215 5 Comparative Example 38 113 0.3 EXPERIENCE 51 251 18 Comparative Example 39 840 18

division Corrosion resistance Coating film adhesion Bending ability Blackness Designability Honors 46 O O O O O Honors 47 O O O O O Honors 48 O O O O O Honorable 49 O O O O O Honors 50 O O O O O EXPERIENCE 51 O O O O O Comparative Example 34 X X O O O Comparative Example 35 O O X O X Comparative Example 36 X X X X X Comparative Example 37 X X X O O Comparative Example 38 X X O X X Comparative Example 39 O O X O X

As shown in Table 14, it was confirmed that the inventive examples 46 to 51 were all excellent in the corrosion resistance, the film adhesion, the bending property, the blackness and the designability by having the thickness of the coating composition satisfying the range proposed by the present invention .

On the other hand, as shown in Table 14, Comparative Examples 34 to 39 have a thickness of a coating composition which does not satisfy the range proposed by the present invention, so that at least two of the corrosion resistance, film adhesion, bending property, It can be confirmed that the physical properties are not satisfactory.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

1: upper layer
2: Substrate steel
3: Lower layer

Claims (27)

Base steel sheet;
A undercoat layer formed on the base steel sheet and formed from a primer composition comprising 0.1 to 10% by weight of an aqueous dispersion phenolic resin, 0.5 to 5% by weight of a metal salt, 1 to 10% by weight of an inorganic acid and a remainder;
Wherein the ink composition is formed on one surface of the undercoat layer and comprises 10 to 80 wt% of a polyester resin, 1 to 45 wt% of a black pigment dispersion, 0.1 to 10 wt% of a wax, 5 to 50 wt% of a crosslinking agent, To 60% by weight, wherein the undercoat layer has an adhesion amount of 30 to 500 mg / m &lt; 2 &gt;, and the thickness of the steel sheet coated with the undercoat layer and the topcoat layer is 1 to 25 mu m Resin coated steel plate.
The method according to claim 1,
A resin-coated steel sheet further comprising an acid catalyst, a quencher, and an adhesion promoter in the top coat composition.
The method according to claim 1,
Wherein the functional group of the water-dispersible phenolic resin is at least one selected from the group consisting of a primary to quaternary amine group or a halogen element.
The method according to claim 1,
The metal salt is selected from the group consisting of magnesium sulfate, magnesium chloride, magnesium nitrate, magnesium acetate, vanadium sulfide, vanadium sulfate, vanadium chloride, manganese sulfate, manganese sulfide, manganese chloride, nickel sulfate, nickel chloride, nickel acetate, nickel sulfide, zinc chloride, zinc At least one selected from the group consisting of zinc chloride, zinc acetate, zirconium phosphate, zirconium chloride and acetate.
The method according to claim 1,
Wherein said inorganic acid comprises at least one member selected from the group consisting of at least one of phosphoric acid and silicic acid, hexafluorozirconic acid, and hexafluorotitanic acid.
The method according to claim 1,
Wherein the polyester resin comprises 20 to 60 mol% of an acid component monomer and 20 to 40 mol% of a polyhydric alcohol.
The method according to claim 6,
Wherein the monomer of the acidic component comprises 20 to 60 mol% of an aromatic acid component, 5 to 40 mol% of an aliphatic acid component, and 1 to 30 mol% of an alicyclic acid component.
The method according to claim 6,
Wherein the polyhydric alcohol is ethylene oxide: 30 to 60 mol% and bisphenol A: 4 to 6 mol%.
The method according to claim 1,
Wherein the black pigment dispersion comprises 10 to 95% by weight of a polyester resin and 0.1 to 25% by weight of a black pigment.
10. The method of claim 9,
Wherein the black pigment is at least one selected from the group consisting of carbon nanotubes, carbon fibers, carbon black, graphite and graphene.
The method according to claim 1,
Wherein the wax is at least one selected from the group consisting of a vegetable wax group and a synthetic resin wax.
The method according to claim 1,
Wherein the crosslinking agent is at least one selected from the group consisting of a melamine crosslinking agent, an isocyanate crosslinking agent and an aziridine crosslinking agent.
The method according to claim 1,
Wherein the mixed solvent comprises a first polymer material having a boiling point of 100 to 180 캜 and a second polymer material having a boiling point of 181 to 240 캜.
14. The method of claim 13,
Wherein the ratio of the first polymer material to the second polymer material is from 10: 1 to 1:10.
14. The method of claim 13,
Wherein the first polymer material is at least one selected from the group consisting of cyclohexane, sorbose 100, toluene, xylene, 1-methoxy-2-propanol, cyclohexanone, and n-butanol.
14. The method of claim 13,
Wherein the second polymeric material is at least one of butyl carbitol, dibasic ester, benzyl alcohol, ethyl benzoate, dimethylaniline, dimethyl sulfoxide, aniline, 1-octanol and 1-
The undercoating composition for use in a resin sheet comprising 0.1 to 10% by weight of a water-dispersible phenol resin, 0.5 to 5% by weight of a metal salt, 1 to 10% by weight of an inorganic acid, and the remainder.
18. The method of claim 17,
An undercoat composition for use in a resin steel sheet further comprising an acid catalyst, a matting agent, and an adhesion promoter in the topcoat composition.
18. The method of claim 17,
Wherein the functional group of the water-dispersible phenol resin is at least one selected from the group consisting of a primary to quaternary amine group or a halogen element.
18. The method of claim 17,
The metal salt is selected from the group consisting of magnesium sulfate, magnesium chloride, magnesium nitrate, magnesium acetate, vanadium sulfide, vanadium sulfate, vanadium chloride, manganese sulfate, manganese sulfide, manganese chloride, nickel sulfate, nickel chloride, nickel acetate, nickel sulfide, zinc chloride, zinc Wherein at least one selected from the group consisting of copper sulfate, zinc chloride, zinc acetate, zirconium phosphate, zirconium chloride, and acetate is used.
18. The method of claim 17,
Wherein said inorganic acid comprises at least one member selected from the group consisting of at least one of phosphoric acid and silicic acid, hexafluorozirconic acid and hexafluorotitanic acid.
Polyester resin: 10 to 80% by weight, black pigment dispersion: 1 to 45% by weight, wax: 0.1 to 10% by weight, crosslinking agent: 5 to 50% by weight and mixed solvent: 5 to 60% by weight Topcoat composition used for steel sheet.
23. The method of claim 22,
The polyester resin is a top coat composition used for the resin coated steel sheet containing 20 to 60 mol% of monomers of the acid component, 20 to 40 mol% of polyhydric alcohols.
23. The method of claim 22,
The black pigment dispersion is a top coat composition for use in a resin coated steel sheet comprising a polyester resin: 10 to 95% by weight, black pigment: 0.1 to 25% by weight.
23. The method of claim 22,
The wax is a top coat composition used for the resin coated steel sheet selected from the group consisting of vegetable wax group and synthetic resin wax.
23. The method of claim 22,
The crosslinking agent is a top coat composition used for the resin coated steel sheet is at least one member selected from the group consisting of melamine crosslinking agent, isocyanate crosslinking agent and aziridine crosslinking agent.
23. The method of claim 22,
The mixed solvent is a top coating composition used in the resin coated steel sheet comprising a first polymer material having a boiling point of 100 ~ 180 ℃ and a second polymer material having a boiling point of 181 ~ 240 ℃.

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