KR20140045491A

KR20140045491A - Non chromic acid pre-treatment agent composite and method of mamufacturing uncombustible color steel sheet using the same

Info

Publication number: KR20140045491A
Application number: KR1020140036847A
Authority: KR
Inventors: 장종문; 김용희; 김혜리; 정민영; 정용수
Original assignee: 현대제철 주식회사
Priority date: 2014-03-28
Filing date: 2014-03-28
Publication date: 2014-04-16

Abstract

By applying the water-soluble low-volatile non-chromic acid pretreatment agent, the primer layer and the undercoat coating layer can be omitted, and the eco-friendly aqueous non-chromic acid type which can improve physical properties such as excellent corrosion resistance, processability, impact resistance, and coating film adhesion A pretreatment composition and a method for producing a nonflammable color steel sheet using the same are disclosed.
The non-chromic acid pretreatment composition according to the present invention is polyester resin: 50 to 60% by weight, epoxy binder: 1 to 3% by weight, epoxy-based phosphate compound: 2 to 10% by weight, corrosion inhibitor: 0.5 to 2.0% by weight, collie Id silica: 20 to 30% by weight, additives: 1.0% by weight and the remaining solvent is characterized in that the composition.

Description

Non-chromic acid pretreatment composition and non-flammable color steel sheet manufacturing method using same {NON CHROMIC ACID PRE-TREATMENT AGENT COMPOSITE AND METHOD OF MAMUFACTURING UNCOMBUSTIBLE COLOR STEEL SHEET USING THE SAME}

The present invention relates to a non-chromic acid pretreatment composition and a method for producing a non-flammable color steel sheet using the same, and more particularly, by applying a water-soluble low-volatile non-chromic acid pretreatment agent, it is possible to omit the undercoat layer, but also excellent corrosion resistance, processability, The present invention relates to a non-chromic acid pretreatment composition of an environmentally friendly aqueous type capable of improving physical properties such as impact properties and coating film adhesion, and a method for producing a nonflammable color steel sheet using the same.

In the case of color steel sheets, the demand for building materials, home appliances, and automobiles is increasing. In particular, domestic and foreign cold-rolled product manufacturers and other steel-based surface treatment companies that produce hot-dip galvanized steel and electro-galvanized steel are subjected to chemical treatment such as chromate treatment and phosphate treatment. To produce a product.

Among them, chromate treatment refers to coating a rust preventive film by putting a steel plate in a solution mainly containing chromic acid or dichromate. This chromate treatment is an inexpensive treatment step that gives the steel sheet excellent corrosion resistance and coating film density.

However, since chromium is a representative pollutant and causes serious damage to workers and the environment, regulatory laws have been enacted in developed countries and implementation is being carried out worldwide.

In addition, in the case of chromate-treated steel sheets, hexavalent chromium (Cr ⁺⁶ ) is generated as wastewater in the process, and thus, wastewater treatment is costly and time-consuming, and its use will soon be banned in accordance with international chrome usage regulations. As it is known, research on chromate has not been carried out until now, and researches to develop materials to replace chromium are being actively conducted worldwide.

Therefore, in recent years, the use of chromium-type pretreatment is limited due to environmental regulations, it is necessary to develop a technology that can replace it.

Related prior arts are Korean Patent Registration No. 10-0503164 (July 21, 2005).

An object of the present invention is to apply a water-soluble low-volatile non-chromic acid pretreatment agent, an environmentally friendly aqueous type non-chromic acid pretreatment composition that can improve the physical properties such as excellent corrosion resistance, processability, impact resistance, coating film adhesion, while omission of the undercoat layer And it provides a non-combustible color steel sheet manufacturing method using the same.

Non-chromic acid pretreatment composition according to an embodiment of the present invention for achieving the above object is a polyester resin: 50 to 60% by weight, epoxy binder: 1 to 3% by weight, colloidal silica: 20 to 30% by weight, epoxy-based Phosphoric acid compound: 2 to 10% by weight, silane coupling agent: 0.5 to 1.0% by weight, anticorrosive: 0.5 to 2.0% by weight, additives: 1.0% by weight and the remaining solvents.

Non-combustible color steel sheet manufacturing method according to an embodiment of the present invention for achieving the above object comprises the steps of (a) applying a non-chromic acid pretreatment on the base steel sheet, the first heat drying to form a pretreatment layer; And (b) coating the top coat with a spray coating method on the pretreatment layer, followed by secondary heat drying to form a top coat layer.

Non-chromic acid pretreatment composition according to the present invention and non-flammable color steel sheet manufacturing method using the same is a water-soluble type by using a non-chromic acid pretreatment with a very small amount of volatile organic compounds (VOC), an additional coating treatment with an eco-friendly coating By coating the top coat layer directly on the pretreatment layer by spray-squeezing or dipping without the need to implement the coating layer, the coating layer is omitted, yet excellent corrosion resistance, processability, The appearance quality can be improved by improving the leveling property of the paint while securing impact properties and coating film adhesion.

In addition, the non-chromic acid pretreatment composition according to the present invention and the method of manufacturing a non-flammable color steel sheet using the same, the undercoat layer is omitted, and the thickness of the pretreatment layer is 0.5 to 2.0㎛, while having a very thin thickness specific to the pretreatment agent for ceramic paints. Because of the physical properties, it is possible to minimize the amount of the non-chromic acid pretreatment composition has the advantage of being economic.

1 is a schematic cross-sectional view of a non-combustible color steel sheet according to an embodiment of the present invention.
2 is a process flowchart showing a method for manufacturing a non-flammable color steel sheet according to an embodiment of the present invention.

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

Hereinafter, with reference to the accompanying drawings, a non-chromic acid pretreatment composition according to a preferred embodiment of the present invention and a non-flammable color steel sheet manufacturing method using the same will be described in detail.

Non-Chromic Acid Pretreatment Composition

Non-chromic acid pretreatment composition according to an embodiment of the present invention is a polyester resin: 50 to 60% by weight, epoxy binder: 1 to 3% by weight, colloidal silica: 20 to 30% by weight, epoxy-based phosphate compound: 2 to 10 % By weight, silane coupling agent: 0.5 to 1.0% by weight, corrosion inhibitor: 0.5 to 2.0% by weight and additives: 1.0% by weight.

At this time, the non-chromic acid pretreatment composition according to an embodiment of the present invention is made of a solvent such as distilled water, deionized water, etc. other than the above components, may contain a small amount of impurities inevitably incorporated in the manufacturing process.

Polyester resin

The polyester resin serves as a binder as a main component of the non-chromic acid pretreatment composition. It is preferable to use these polyester resins whose molecular weight is 100,000 or more.

The polyester resin is preferably added in a content ratio of 50 to 60% by weight of the total weight of the non-chromic acid pretreatment composition according to the present invention. When the amount of the polyester resin is less than 50% by weight, the composition for coating may be diluted and may not be easy to dry and use. On the contrary, when the amount of the polyester resin added exceeds 60% by weight, there is a problem that the curing characteristics are lowered, or the leveling property is lowered by increasing the curing time and increasing the concentration.

Epoxy binder

An epoxy binder is added for the purpose of improving adhesiveness. It is preferable to use an epoxy resin as such an epoxy binder.

The epoxy binder is preferably added in an amount of 1 to 3% by weight of the total weight of the non-chromic acid pretreatment composition according to the present invention. If the added amount of the epoxy binder is less than 1% by weight, it may be difficult to properly exhibit the above effects. On the contrary, when the addition amount of an epoxy binder exceeds 3 weight%, there exists a problem that heat resistance falls.

Colloidal silica

Colloidal silica contributes to hardness and corrosion resistance. Such colloidal silica is preferably used having an average diameter of 5 ~ 15nm, since it can be atomized into a colloidal form to be stabilized in the solvent.

The colloidal silica is preferably added in an amount of 20 to 30% by weight of the total weight of the non-chromic acid pretreatment composition according to the present invention. If the amount of colloidal silica is less than 20% by weight, it may be difficult to properly exhibit the effect of improving hardness and corrosion resistance. On the contrary, when the addition amount of colloidal silica exceeds 30 weight%, it becomes difficult to form a top coat film, or there exists a problem that workability worsens by the adhesiveness fall of a coating film. In particular, the polyester resin and colloidal silica are preferably added in a ratio of 1.5: 1 to 2.5: 1.

Epoxy Phosphate Compound

Epoxy-based phosphate compound improves the adhesion of the coating film by activating the surface etching and epoxy groups and also improves the corrosion resistance. As the epoxy-based phosphate compound, any one selected from 1-hydroxyethylene-1,1-diphosphonic acid, ammonium phosphate, sodium monophosphate, sodium diphosphate, sodium triphosphate and zinc phosphate may be used.

The epoxy-based phosphate compound is preferably added in a content ratio of 2 to 10% by weight of the total weight of the non-chromic acid pretreatment composition according to the present invention. If the added amount of the epoxy-based phosphate compound is less than 2% by weight, it may be difficult to properly exhibit the effect of improving the corrosion resistance since the added amount is insignificant. On the contrary, when the added amount of the epoxy-based phosphate compound exceeds 10% by weight, it is not economical because it acts as a factor to increase the manufacturing cost without any further effect.

Silane coupling agent

The silane coupling agent serves to increase the crosslinking force and to improve adhesion.

The silane coupling agent is preferably added in a content ratio of 0.5 to 1.0% by weight of the total weight of the non-chromic acid pretreatment composition. When the amount of the silane coupling agent added is less than 0.5% by weight, the adhesion may be inferior. On the contrary, when the amount of the silane coupling agent added exceeds 1.0 wt%, the viscosity may not be evenly applied to the surface of the steel sheet due to the viscosity increase, and the surface treatment characteristics may be deteriorated.

Examples of the silane coupling agent include 3-aminopropyltriepoxysilane, N, N-bis [3- (trimethoxysilyl) propyl] ethylenediamine, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- [2- (vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane, N- (1,3-dimethylbutylidene) -3- (triepoxysilane) -1-propanamine, 3- One selected from glycidoxypropyltrimethoxysilane, 3-methaglycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxy trimethyl dimethoxysil, and the like can be used.

Anticorrosion

Corrosion resistance improves hardness and corrosion resistance. As the corrosion inhibitor, one or more selected from titanium sol, silica sol, zirconium sol and the like may be used, but it is more preferable to use a titanium sol.

The corrosion inhibitor is preferably added in an amount ratio of 0.5 to 2.0% by weight of the total weight of the non-chromic acid pretreatment composition according to the present invention. If the amount of the corrosion inhibitor is less than 0.5% by weight, it may be difficult to properly exhibit the effect of improving hardness and corrosion resistance. On the contrary, when the addition amount of a corrosion inhibitor exceeds 2.0 weight%, coating film formation may become difficult or the adhesiveness of a coating film may fall.

Other additives

Other additives may be added to the non-chromic acid pretreatment composition according to the present invention. Such additives may be further added at least one selected from a leveling agent, an antifoaming agent, and the like, and the additives are preferably added in an amount ratio of 1.0 weight or less of the total weight of the non-chromic acid pretreatment composition according to the present invention.

The non-chromic acid pretreatment composition according to the embodiment of the present invention is a water-soluble type because it has very few volatile organic compounds (VOCs), which enables eco-friendly coating, and has a structure in which the undercoat layer is omitted and has excellent corrosion resistance. In addition to ensuring workability, impact resistance, coating adhesion, and the like, the appearance quality can be improved by improving the leveling property of the coating material.

Manufacturing method of incombustible color steel plate

Hereinafter, the non-combustible color steel sheet manufacturing method according to an embodiment of the present invention to be described in more detail.

1 is a cross-sectional view schematically showing a non-flammable color steel sheet according to an embodiment of the present invention, Figure 2 is a process flow chart showing a method for manufacturing a non-flammable color steel sheet according to an embodiment of the present invention.

1 and 2, the method for manufacturing a non-flammable color steel sheet according to the embodiment of the present invention includes a pretreatment layer forming step S210 and a top coat layer forming step S220.

Formation of pretreatment layer

In the pretreatment layer forming step (S210), after applying the non-chromic acid pretreatment agent on the base steel plate 120, the pretreatment layer 140 is formed by primary heat drying.

At this time, the non-chromic acid pretreatment composition is polyester resin: 50 to 60% by weight, epoxy binder: 1 to 3% by weight, colloidal silica: 20 to 30% by weight, epoxy phosphate compound: 2 to 10% by weight, silane coupler Ring agent: 0.5 to 1.0% by weight, corrosion agent: 0.5 to 2.0% by weight and additives: 1.0% by weight.

In addition, the non-chromic acid pretreatment composition is made of a solvent such as distilled water, deionized water, etc. in addition to the above components, and may contain a small amount of impurities inevitably incorporated in the manufacturing process.

In this case, the coating of the non-chromic acid pretreatment may be performed by one or more of spray-squeezing, roll coating, and dipping methods, and using the roll coating method. More preferred.

The base steel plate 120 may be any one selected from a hot dip galvanized steel sheet, an electrogalvanized steel sheet, and the like. 1 illustrates that the pretreatment layer 140 is coated only on the upper surface of the base steel sheet 120, but is not limited thereto. The pretreatment layer 140 may be coated only on the lower surface of the base steel sheet 120 or may be coated on both the upper and lower surfaces. .

The pretreatment layer 140 simultaneously performs the function of the undercoat layer as well as the purpose of performing surface treatment of the base steel sheet 120 before the painting, so that the undercoat layer can be omitted.

In particular, the pretreatment layer 140 is preferably formed to a thickness of 0.5 ~ 2.0㎛. When the thickness of the pretreatment layer 140 is less than 0.5 μm, the workability may be improved, but the corrosion resistance and the adhesion may be reduced, which is not preferable. On the contrary, when the thickness of the pretreatment layer 140 exceeds 2.0 μm, the pretreatment layer 140 acts as a factor to increase the thickness of the coating layer without any further effect. The increase in the thickness of the coating layer not only lowers the workability but also causes cracking. Can be.

In this step, the first heat drying temperature (Peak Metal Temperture: PMT) is preferably carried out at 160 ~ 200 ℃ conditions. If the primary heat drying temperature is less than 160 ℃ drying may not be completed completely, workability may be reduced. On the contrary, when the primary heat drying temperature exceeds 200 ° C., the adhesion between the pretreatment layer 140 and the base steel sheet 120 may be lowered due to abnormal drying, which may result in deterioration of overall surface properties. At this time, the drying is preferably carried out by at least one of hot air heating method, induction heating method and near-infrared heating method.

Top coat layer formation

In the top coat layer forming step (S220), after coating the top coat with a spray coating method on the pretreatment layer 140, secondary heat drying is performed to form the top coat layer 160.

At this time, the top coat is a composition composed of 40 to 50% by weight of polyester resin, 5 to 6% by weight of melamine cured resin, pigment 20 to 30% by weight, solvent 10 to 20% by weight and additives 10 to 20% by weight. Can be.

In this case, at least one selected from TiO ₂ , antimony (Sb), carbon (C), iron oxide and silicon (Si) may be used as the pigment, and at least one selected from hydrocarbon and cyclonucleic acid may be used as the solvent. As an additive, at least one selected from acrylic, urethane, and epoxy may be used.

The top coat layer 160 may have a thickness of 10 ~ 30㎛. When the thickness of the top coat layer 160 is less than 10 μm, it may be difficult to secure physical properties such as corrosion resistance and scratch resistance. On the contrary, when the thickness of the top coat layer 160 exceeds 30 µm, there is a problem in that adhesiveness and workability are lowered.

In this step, the top coat coating may be performed by one or more of spray squeezing, roll coating, and dipping, and double spray-squeezing. It is preferable to use. As such, when the top coat is coated by the spray-squeegeeing method, the manufacturing process may be simplified by applying the spray process to improve the production yield.

At this time, the secondary heat drying temperature (Peak Metal Temperture: PMT) is preferably carried out under 200 ~ 250 ℃ conditions. If the secondary heat drying temperature is less than 200 ℃ can not cause a sufficient curing reaction can lead to a decrease in physical properties. On the contrary, when the secondary heat drying temperature exceeds 250 ° C., abnormal surface drying may cause a decrease in surface quality due to a decrease in coating film adhesion. At this time, the drying is preferably carried out by at least one of hot air heating method, induction heating method and near-infrared heating method.

The non-combustible color steel sheet produced by the above process (S210 ~ S220) is a water-soluble type, which uses a non-chromic acid pretreatment that is very low in volatile organic compounds (VOCs), thereby performing separate undercoat with an eco-friendly coating. By coating the top coat layer on the pretreatment layer directly by spray squeezing or dipping method without having to do so, it has a structure in which the undercoat layer is omitted, yet excellent corrosion resistance, processability, impact resistance, coating film Not only the adhesiveness can be secured but also the appearance quality can be improved by improving the leveling property of the paint.

In addition, the non-combustible color steel sheet produced by the method according to the present invention, the undercoat layer is omitted, and the thickness of the pretreatment layer is 0.5 ~ 2.0㎛, while having a very thin thickness and has the specific properties of the pretreatment agent for ceramic paints, It is economical because the amount of the chromic acid pretreatment composition can be minimized.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

1. Preparation of Color Steel Specimen

Example 1

On a galvanized steel sheet, polyester resin: 54 wt%, epoxy resin: 2 wt% colloidal silica: 25 wt%, ammonium phosphate: 3.0 wt%, 3-aminopropyltriepoxysilane: 1.5 wt%, titanium sol: 0.5 wt%, The non-chromic acid pretreatment composition, which is composed of 1 wt% and the remaining water by the addition of the leveling agent and the antifoaming agent as the other additives, was applied to a thickness of 0.3 μm, and then dried first at 160 ° C. to form a pretreatment layer.

Next, after coating a coating composition composed of 45wt% of polyester resin, 5wt% of melamine cured resin, 25wt% of TiO ₂ , 18wt% of hydrocarbon and 17% of urethane resin on the pretreatment layer, it was heated at 200 ° C. for 2 hours. It was dried to form a top coat layer of 21㎛ thickness to prepare a color steel specimen.

Example 2

Polyester resin: 52 wt%, epoxy resin: 2.5 wt% colloidal silica: 27 wt%, ammonium phosphate: 6.0 wt%, 3-aminopropyltriepoxysilane: 2.0 wt%, titanium sol: 1.5 wt%, leveling agent with other additives And the color steel sheet specimens were prepared in the same manner as in Example 1 except that the non-chromic acid pretreatment composition composed of 1wt% and the remaining water by the sum of the antifoaming agent was applied to a thickness of 0.5㎛.

Example 3

Polyester resin: 57 wt%, epoxy resin: 2.2 wt% colloidal silica: 23 wt%, ammonium phosphate: 8.0 wt%, 3-aminopropyltriepoxysilane: 2.5 wt%, titanium sol: 1.0 wt%, leveling agent with other additives And a non-chromic acid pretreatment composition composed of 1wt% and the remaining water by the sum of the antifoaming agent was applied to a thickness of 0.7㎛, and the color steel specimen was prepared in the same manner as in Example 1 except that the first heat-drying at 170 ℃. .

Example 4

A color steel specimen was prepared in the same manner as in Example 1 except that the non-chromic acid pretreatment composition was applied at a thickness of 1.0 μm and dried firstly at 170 ° C.

Example 5

A color steel sheet specimen was prepared in the same manner as in Example 1 except that the non-chromic acid pretreatment composition was applied at a thickness of 1.5 μm and dried firstly at 180 ° C.

Example 6

A color steel sheet specimen was prepared in the same manner as in Example 1 except that the non-chromic acid pretreatment composition was applied to a thickness of 2.0 μm and dried firstly at 200 ° C.

Comparative Example 1

A color steel specimen was prepared in the same manner as in Example 1 except that the non-chromic acid pretreatment composition was applied to a thickness of 2.5 μm and dried firstly at 180 ° C.

2. Property evaluation method

Physical properties evaluation method of the color steel sheet specimens prepared according to Examples 1 to 6 and Comparative Example 1 are as follows.

(1) Glossiness

For gloss evaluation, the gloss of the specimen was measured at an incident angle of 60 ° using a gloss meter (Tri-Microgloss-20-60-85, Sheen Instruments Ltd., England).

(2) corrosion resistance

Corrosion resistance evaluation was performed after 350 hours of neutral salt spray test to confirm the coating peeling, lifting, plating surface corrosion, rust generation. The evaluation criteria are as follows.

Good (O): No peeling, lifting, plating surface corrosion and rust

Poor (X): Peeling, lifting, plating surface corrosion or rust

(3) impact resistance

Impact resistance was evaluated for cracking after surface impact under a condition of 1 / 2φ × 1kg × 500mm.

Good (O): No crack

Poor (X): Cracks

(4) Processability

Machinability was tested by T-bending test to determine whether cracks occurred at twice the bending thickness of the specimen.

Good (O): No crack

Poor (X): Cracks

(5) Coating Hardness

The coating hardness evaluation was evaluated by rubbing 50 times with 1kgf force after applying MEK to gauze, and then peeling and swelling of resin.

Good (O): No resin peeling or swelling

Poor (X): resin peeling or swelling

(6) Pencil Hardness

The pencil hardness used the uni pencil (made by Mitsubishi Corporation, Japan).

(7) Coating film adhesion (adhesiveness)

Coating adhesion is cross-cutting by 10 rows at the interval of 1mm in width x length on the flat sample coated with paint to make 100 squares with an area of 1mm 2, and then cross-cut to 6mm in height. ) Spherical processing (Ericsson processing) was carried out on the flat plate portion, and when the adhesive tape was finally attached and then peeled off to 100 coating film particles was evaluated as follows.

Good (O): No peeling of the coating film particles of the cross cutting part

Poor (X): Peeling of the coating film particles of the cross cutting part

3. Property evaluation

Table 1 shows the results of physical properties evaluation for the specimens according to Examples 1 to 5 and Comparative Example 1.

[Table 1]

Referring to Table 1, in the case of the specimens according to Examples 1 to 5, it was confirmed that the corrosion resistance, impact resistance, processability, coating film hardness, pencil hardness and coating film adhesion meet all of the target property values. In particular, in the case of the specimens according to Examples 1 to 6, the pencil hardness was all measured by 2H, the glossiness was measured by 90 ~ 94.

On the other hand, in the case of the specimen according to Comparative Example 1, the thickness range of the non-chromic acid pretreatment composition is out of the range suggested by the present invention, the corrosion resistance, processability, coating hardness and pencil hardness satisfy the target physical property values, but the glossiness Was measured as 89, and it was confirmed that the impact resistance and the coating film adhesion were poor.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Such changes and modifications are intended to fall within the scope of the present invention unless they depart from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

100: non-flammable color steel sheet 120: base steel sheet
140: pretreatment layer 160: top coat layer
S210: Pre-treatment layer formation step
S220: top coat layer forming step

Claims

Polyester resin: 50 to 60% by weight,
Epoxy binder: 1-3 wt%,
Colloidal silica: 20-30% by weight,
Epoxy Phosphate Compound: 2 ~ 10 wt%
Silane coupling agent: 0.5-1.0 wt%,
Anticorrosive: 0.5-2.0 wt%,
Additive: Bichromic acid pretreatment composition, characterized in that the composition is composed of 1.0% by weight and the remaining solvent.

The method of claim 1,
The polyester resin and the colloidal silica
Non-chromic acid pretreatment composition, characterized in that it is added in a ratio of 1.5: 1 to 2.5: 1.

The method of claim 1,
The epoxy-based phosphate compound
A non-chromic acid pretreatment composition comprising at least one selected from 1-hydroxyethylene-1,1-diphosphonic acid, ammonium phosphate, sodium monophosphate, sodium diphosphate, sodium triphosphate, and zinc phosphate.

(a) applying a non-chromic acid pretreatment agent on the base steel sheet, followed by primary heat drying to form a pretreatment layer; And
(b) coating a top coat with a spray coating method on the pretreatment layer, followed by secondary heat drying to form a top coat layer; and a nonflammable color steel sheet manufacturing method comprising a.

5. The method of claim 4,
In the step (a)
The non-chromic acid pretreatment agent
Polyester resin: 50 to 60% by weight, epoxy binder: 1 to 3% by weight, colloidal silica: 20 to 30% by weight, epoxy phosphate compound: 2 to 10% by weight, silane coupling agent: 0.5 to 1.0% by weight, Anticorrosive: 0.5 to 2.0% by weight, additives: 1.0% by weight and the method of producing a non-flammable color steel sheet, characterized in that it is composed of the remaining solvent.

5. The method of claim 4,
The pretreatment layer is
Non-flammable color steel sheet manufacturing method characterized by having a thickness of 0.5 ~ 2.0㎛.

5. The method of claim 4,
In the step (a)
The first heat drying temperature (Peak Metal Temperture: PMT) is
Non-combustible color steel sheet manufacturing method characterized in that carried out at 160 ~ 200 ℃ conditions.

5. The method of claim 4,
In the step (b)
The secondary heat drying temperature (Peak Metal Temperture: PMT)
Non-combustible color steel sheet manufacturing method characterized in that carried out at 200 ~ 250 ℃ conditions.