KR101162681B1 - Environment-Friendly Organic Coating Colored Steel Plate and Method For Preparing the Same - Google Patents

Abstract

The present invention relates to a method for producing an environmentally-friendly organic coated color steel sheet for producing a color steel sheet on a plating line without containing environmental regulatory substances such as chromium and phosphoric acid, including (i) 50 to 80 wt% of an aqueous resin composition; 10 to 30% by weight rust inhibitor; Preparing a first liquid by mixing 0-10% by weight of an additive and 1-10% by weight of water, (ii) mixing a pigment, a co-solvent, a dispersant, and an aqueous solvent, and then dispersing it with a disperser to prepare a second liquid. Step, (iii) mixing the first liquid, the second liquid and water to produce a water-soluble colored paint composition, and (iv) applying and drying the water-soluble colored paint composition on a steel sheet to color on a continuous plating line. Forming a coating layer.

Description

Eco-friendly organic coated colored steel plate and manufacturing method thereof {Environment-Friendly Organic Coating Colored Steel Plate and Method For Preparing the Same}

The present invention relates to an environmentally-friendly organic coated color steel sheet and a method for manufacturing the same, which comprises a water-soluble colored coating composition containing no pigments and environmentally harmful substances to produce a color steel sheet on a plating line in manufacturing a steel sheet. It is about a method.

Galvanized steel is highly corroded in a wet environment, and is easily exposed to surface defects such as surface contamination by organic materials such as fingerprints, temper color discoloration caused by rolling and annealing processes, contamination by poor degreasing and contamination by poor water washing. have. In addition, it is harmful to humans due to the treatment of chromate containing hexavalent chromium regulated by RoHS to supplement corrosion resistance (RoHS regulation: hazardous substance -hexavalent chromium, cadmium, mercury, lead).

Therefore, there is a demand worldwide to not use harmful heavy metal materials for steel plates for construction and home appliances. In this study, researches on oil and inorganic coatings such as molybdenum anion passivation coating, heavy acid salt coating, tannic acid coating, etc., but all of them have protective and self-healing properties compared to conventional chromate coatings. Healing) is lacking.

In addition, the steel sheet used as the exterior material of home appliances to give a variety of colors, including black bar, usually coated with oil paint on a plated steel sheet to produce a color steel sheet. In order to coat paint on plated steel sheet, the plated steel sheet produced in the plating line must be transferred to the color coating line (CCL) for work, which reduces workability and increases the process cost. Is generated in large quantities, which is undesirable from an environmental point of view.

Therefore, manufacturing color steel sheet in the plating line is advantageous in terms of process, but due to problems such as color difference between product lots, coating roll marks, insufficient corrosion resistance and poor press workability, it has been applied to practical use until now. No suitable product has been developed.

The present invention is to solve the technical problems that have been requested from the problems and demands of the prior art as described above.

An object of the present invention is to provide an environmentally friendly organic coated color steel sheet produced directly from the plating line while exhibiting excellent physical properties.

The present invention is to provide a method for manufacturing an environmentally friendly organic coated color steel sheet that is easy to process and reduce the manufacturing cost by performing color coloring in the plating line, and by using an aqueous coating liquid to exhibit environmentally friendly, uniform and beautiful color. .

In order to form a coating composition by mixing and dispersing the water-soluble resin and the coloring pigment together to form the organic coated color steel sheet in the plating line, problems such as water-soluble resin components entangled with each other or deteriorated in the process of dispersing the coloring pigment Occurs.

Therefore, the inventors of the present application, after dispersing the first liquid containing the water-based resin composition and the second liquid containing the colored pigment in the disperser and mixed the first liquid and the second liquid with each other, the water-soluble water pigments dispersed effectively It was confirmed that the coating composition may be prepared and a colored organic steel sheet having excellent physical properties and surface properties may be prepared when the coating composition is applied in a plating line.

According to one example, the environmentally friendly organic coated color steel sheet may be manufactured by a method comprising the following steps.

(i) 50 to 80% by weight of the aqueous resin composition; 10 to 30% by weight rust inhibitor; Preparing a first liquid by mixing 0-10 wt% of an additive and 1-10 wt% of water;

(ii) mixing a pigment, a co-solvent and a dispersant with an aqueous solvent, and then dispersing it with a disperser to prepare a second liquid;

(iii) mixing the first liquid, the second liquid and water to prepare a water-soluble colored paint composition; And

(iv) applying and drying the water-soluble colored coating composition on the base steel sheet to form a color coating layer on the continuous plating line.

In some cases, on the color coating layer prepared in step (iv),

(v) 50 to 80 wt% of the aqueous resin composition; 10 to 30% by weight rust inhibitor; And applying and drying a clear coating composition prepared by mixing 0 to 10 wt% of an additive to form a clear coating layer; It may further include

According to the production method of the present invention, a water-soluble coating composition prepared using an aqueous resin and an aqueous solvent is directly applied onto the steel sheet without undergoing a pretreatment process of an environmental regulatory substance such as phosphate or chromium on the steel sheet. Therefore, it is possible to manufacture environmentally friendly products that do not contain environmentally harmful substances such as VOC generated from chromium or oil based paints.

Furthermore, by effectively dispersing the colored pigment in the water-soluble coating composition and minimizing deterioration of the resin composition, it is possible to immediately produce a color steel sheet having excellent surface properties and physical properties and suitable for practical use on a plating line.

Therefore, it is not necessary to go through the color coating line process for the separate color coating, so that the process can be simplified, and excellent color steel sheet can be manufactured without going through chromate pretreatment process as well as using water-based paint rather than oil-based paint. It is a breakthrough technology in that sense.

The first liquid contains an aqueous resin composition, a rust preventive agent, and an additive.

The aqueous resin composition may be a water-soluble or water-dispersible resin. Specific examples thereof include, but are not limited to, dispersible polyurethanes, emulsion acrylic resins, water-soluble modified polyolefins, and mixtures or composites thereof. In one example, the aqueous resin composition is water-soluble or water-dispersible, it may be composed of 50 to 100% by weight of polyolefin resin, 0 to 50% by weight of emulsion acrylic resin, and 0 to 50% by weight of polyurethane dispersion resin. As such, when the content of the polyolefin is 50% or more, the corrosion resistance, hardness and workability, workability is excellent.

In the resin composition, the average particle diameter (D50) of the resin is 100 nm or less, the number average molecular weight is 5000 to 25000, the curing temperature is PMT (Peak Metal Temperature) 120 to 180 ℃, pH may be 7-11.

In addition, the resin composition may further include a crosslinking agent, and examples of the crosslinking agent may include at least one selected from the group consisting of melamine resin, epoxy resin, isocyanate resin, and copolymers, composites or mixtures thereof. It is not limited to this.

The said rust preventive agent is not specifically limited, For example, the complex complex of Ti type and Mo type is mentioned. Such complex complexes may be surface coated with silicon or silica to improve surface properties.

The additive is not particularly limited, and examples thereof include one or more selected from the group consisting of a leveling agent, an antifoaming agent, and a storage stabilizer.

The content of each component in the first liquid can be appropriately adjusted by those skilled in the art, preferably 50 to 80% by weight, or 55 to 65% by weight of the aqueous resin composition, 10 to 30% by weight, or 15 to 15% rust preventive agent 25 weight percent, and additives 2-5 weight percent.

The second liquid is a coloring pigment, a co-solvent and a dispersant are mixed with an aqueous solvent, the coloring pigment is a non-chromic or non-phosphate pigment, one or more pigments selected from pigments used in paints such as organic pigments, inorganic pigments, etc. It may include. The content of the pigment may be included in an amount of 1 to 15% by weight, or 5 to 15% by weight, but is not limited thereto.

The plating line may be any one of an electro zinc plating line or a hot dip zinc plating line, and an alloyed hot dip zinc plating line, but is not limited thereto.

Another aspect of the present invention provides an environmentally friendly organic coated color steel sheet manufactured in a continuous plating line by the above method.

Another aspect of the present invention provides an environmentally friendly organic coated color steel sheet, which is directly formed on the base steel sheet, and a color coating layer formed of a water-soluble resin and a color pigment.

These eco-friendly organic coated color steel sheets are chrome-free and are eco-friendly, and the color steel plates for home appliances produced by the color coating line (CCL) that are used in the existing properties such as corrosion resistance, coating adhesion, processability, and chemical resistance are Shows equivalent performance. In particular, since color steel sheets can be produced in plating lines such as EGL and CGL without using a color coating line (CCL), the production cost can be dramatically improved, and since the coating agent used is environmentally water-soluble, VOC is generated. It is also excellent for improving the working environment. Therefore, the eco-friendly organic coated color steel sheet can be effectively used for exterior materials of home appliances.

Advantages and features of the present invention and methods of performing the same will be more readily understood by referring to the detailed description and accompanying drawings in the following preferred embodiments. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

One. Manufacturing method of eco-friendly organic coated color steel sheet

According to an embodiment of the present invention, the environmentally friendly organic coated color steel sheet may be manufactured by a method comprising the following steps (i) to (iv).

(i) 50 to 80% by weight of the aqueous resin composition; 10 to 30% by weight rust inhibitor; Preparing a first liquid by mixing 0-10 wt% of an additive and 1-10 wt% of water;

(ii) mixing a pigment, a co-solvent and a dispersant with an aqueous solvent, and then dispersing it with a disperser to prepare a second liquid;

(iii) mixing the first liquid, the second liquid and water to prepare a water-soluble colored paint composition; And

(iv) applying and drying the water-soluble colored coating composition on a continuous plating line to form a color coating layer.

In some cases, a clear coating layer may be further formed on the color coating layer prepared in step (iv) as follows.

(v) 50 to 80 wt% of the aqueous resin composition; 10 to 30% by weight rust inhibitor; And applying a clear coating composition prepared by mixing 0 to 10 wt% of the additive to form a clear coating layer.

Conventional oil paints are prepared through a dispersion process by including a color pigment in the resin at the time of manufacture. The dispersing process is a step of distributing the pigment to be supplied in small and even units in a unit of particles, which is essential for making a color coating. However, in the case of the water-soluble resin, when the dispersion process including the pigment is carried out, there is a fear of gelation and deterioration of the resin during dispersion depending on the characteristics of the resin. Therefore, it is difficult to apply the process of manufacturing oil paint as it is.

Therefore, in this invention, the process of manufacturing the 1st liquid which is a transparent paint containing water-soluble resin, and disperse | distributing and mixing a book pigment with the component except resin in this transparent paint was taken. That is, a first liquid containing an aqueous resin composition and a second liquid containing a colored pigment are separately formed, and the first liquid and the second liquid are mixed to prepare a water-soluble colored coating composition. As a result, a beautiful color can be expressed by uniformly dispersing and distributing the coloring pigment in the aqueous resin composition.

In addition, a water-soluble coating composition prepared by using an aqueous resin and an aqueous solvent is directly applied onto the steel sheet without undergoing a pretreatment process of an environmental regulatory substance such as phosphate or chromium on the steel sheet. Therefore, it is possible to manufacture environmentally friendly products that do not contain environmentally harmful substances such as VOC generated from chromium or oil based paints.

In addition, the color steel sheet produced according to the present invention can exhibit excellent physical properties with little color difference between lots while exhibiting corrosion resistance, chemical resistance, processability, and coating film adhesion.

The plating line may be any one of an electro zinc plating line or a hot dip zinc plating line, and an alloyed hot dip zinc plating line, but is not limited thereto.

The coating of the water-soluble colored paint composition on the steel sheet may be performed using, for example, a roll coater in a continuous line. The resin composition may be cured through drying after application of the composition, and the drying may be performed by using a separate drying furnace, and the drying and / or curing process may be performed at a peak metal temperature of 120 to 180 ° C. Can be.

Hereinafter, look at each component.

(1) Preparation of First Liquid

The first liquid is 50 to 80% by weight of the aqueous resin composition; 10 to 30% by weight rust inhibitor; It is prepared by mixing 0-10 wt% of additives and 1-10 wt% of water.

Water-based resin composition

The aqueous resin composition may be made of a water-soluble or water-dispersible resin. Examples include, but are not limited to, dispersion polyurethanes, emulsion acrylic resins, water soluble modified polyolefins, and mixtures or composites thereof. In one example, the water-based resin composition is water-soluble or water-dispersible, it may be composed of 50 to 100% by weight of polyolefin resin, 0 to 50% by weight of emulsion acrylic resin, and 0 to 50% by weight of polyurethane dispersion resin.

The polyolefin resin may include, for example, polyethylene (PE), polypropylene (PP), polyisobutylene (PIB), polyvinyl alcohol (PVA), but is not limited thereto. Polyolefin resin in the present invention encompasses all copolymers, grafts, modified resins, self-crosslinked resins. Examples of the water-soluble polyolefin resins include unsaturated carboxylic acids or acid anhydride-modified polyolefins. Such a modified polyolefin can usually be obtained by graft polymerization of unsaturated carboxylic acid or acid anhydride to the polyolefin according to a known method per se, and a catalyst can be used if necessary. The polyolefin includes, for example, an unchlorinated polyolefin formed by (co) polymerizing one or two or more kinds of olefins having 2 to 10 carbon atoms, such as ethylene, propylene, butylene, and hexene, and particularly, propylene. It is especially preferable to contain as a polymerization unit.

Moreover, as unsaturated carboxylic acid or acid anhydride, C3-C10 aliphatic carboxylic acid or its anhydride which contains at least 1 polymeric double bond in 1 molecule, and also does not contain chlorine is contained, Specifically, For example, (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride, etc. are mentioned.

The unsaturated carboxylic acid or acid anhydride modified polyolefin may be further acrylic modified as needed. As an acrylic unsaturated monomer for this, For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) ) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) C ₁ ~ C ₂₁ alkyl esters of acrylic acid, such as an aryl group; (Meth) acrylate, 2-hydroxyethyl (meth) (meth) C ₁ ~ C ₂₁ hydroxyalkyl esters of acrylic acid such as acrylic acid 3-hydroxypropyl; Other acrylic monomers, such as (meth) acrylic acid, (meth) acrylic-acid glycidyl, (meth) acrylamide, (meth) acrylonitrile, etc. are mentioned, These can be used individually or in combination of 2 or more types, respectively. Can be.

When the content of the total resin, including the polyolefin-based resin in the resin composition is less than 50% by weight, it is difficult to exhibit the overall physical properties such as corrosion resistance, hardness, workability, it is preferably 50% or more, and considering the coloring power, hiding power and coating film adhesion, It is preferably included in 70% by weight or less.

The resin composition may be made of only a water-soluble or water-dispersible polyolefin resin, but may be mixed with other resins for further improving corrosion resistance.

The acrylic resin may preferably be an emulsion type. The polyurethane resin may be, for example, a polyurethane dispersion resin. The acrylic resin or polyurethane resin may contain groups other than urethane groups in the polymer backbone.

In another preferred embodiment, the resin composition may further include a crosslinking agent, and examples of the crosslinking agent include 1 selected from the group consisting of amino resins, epoxy resins, isocyanate resins, and copolymers, composites or mixtures thereof. Although a species is mentioned, It is not limited to this.

Examples of the amino resins include melamine resins, urea resins, benzoguanamine resins, and the like. Examples of the melamine resin include alkyl etherified melamine resins etherified with alkyl groups such as methyl, ethyl, n-butyl, isobutyl, hexyl and 2-ethylhexyl, for example. In the case of the melamine resin, the strength and durability may be increased by increasing the degree of curing of the water-soluble resin.

The epoxy compound may react with the carboxyl group in the modified polyolefin. The epoxy compound is not particularly limited as long as it has at least two epoxy groups per molecule, and examples thereof include bisphenol type epoxy resins, novolac type epoxy resins, polyethylene glycol diglycidyl ethers, and the like. In the case of such an epoxy resin, there is an advantage that the adhesion between the layers and the rust resistance of the metal sheet can be improved.

The isocyanate resins include not only free isocyanates but also protected isocyanates. In view of compatibility with low temperature curability and modified polyolefins, blocked isocyanates that impart water dispersibility can be preferably used. For example, blocking isocyanate groups are blocked with a blocking agent containing hydroxy monocarboxylic acid, and neutralized carboxyl groups introduced with hydroxy monocarboxylic acid are added, such as blocked polyisocyanates and surfactants, which impart water dispersibility. Or water-oxidized by the reaction.

The content of the crosslinking agent may be included in an amount of 5 to 15% by weight based on the total content of the water-soluble resin composition in terms of compatibility with the water-soluble resin composition, curability, adhesion, water resistance, and the like.

Each resin including the polyolefin-based resin is preferably 100 nm or less because the appearance after drying becomes poor when the particle size becomes 100 nm or more during solubilization. In addition, the respective resins may have poor film properties when the number average molecular weight is less than 5000, and when the number average molecular weight exceeds 25000, the viscosity of the resin may be excessively increased, making it difficult to use for coating. It is preferable that it is 5000-20000.

In addition, the curing temperature of the resin is preferably PMT (Peak Metal Temperature) 120 to 180 ℃, more preferably PMT 120 to 160 ℃ considering the production efficiency, such as heat resistance and manufacturing cost of the substrate, more preferably one-part partial thermosetting It is preferable that it is resin.

On the other hand, the coating composition according to the present invention includes a color pigment, the mixing of the resin and the color pigment is important, stability is also important. Thus, the pH of the resin is preferably adjusted to neutral to alkali, so that the pH may be 7 to 11.

Rust preventive

When only the water-soluble resin composition is used, the hardness is low at the time of coating due to low crystallinity, and it is difficult to expect satisfactory corrosion resistance. Thus, in order to effectively block the occurrence of white rust of the steel sheet is added to use a rust inhibitor.

In this regard, conventional hexavalent chromium is used for corrosion inhibition, but it is regulated because it causes environmental problems, and numerous research methods have been developed to replace chromium. Typical examples include ① development of rust preventive agents using molybdate (having a similar rust-proofing mechanism tendency as chromium) or ② use of tannic acid (effective formation of chelate with zinc through OH radicals) ③ silicate and Method of using electrolytic phosphate coating (anticorrosive effect by using inorganic polymer compound) (4) A method using organic coating (organic coating) or the like has been advanced. However, when these rust inhibitors are used alone, it is difficult to satisfy high corrosion resistance.

Thus, in the present invention, a rust preventive agent capable of imparting anti-rust performance and coating hardness and adhesion to a material without using chromium is used. As such rust inhibitors, Most's MRCI-10, Ken-react's LICA 38J and the product Kemetall's, etc. may be used, and Most's MRCI-10 is preferably used.

The content of the rust preventive agent is preferably 10 to 30% by weight of the total composition, if less than 10% by weight it is difficult to expect the improvement of corrosion resistance and hardness, when it exceeds 30% by weight there is a concern that the film adhesion and appearance deteriorate have.

additive

Various additives may also be added to the water-soluble coating composition. Examples of the additives include a leveling agent, an antifoaming agent, a storage stabilizer, and the like, but are not limited thereto. The additives may be two or more mixed.

(2) Preparation of Second Liquid

The second liquid is prepared by mixing a coloring pigment, a co-solvent and a dispersant with an aqueous solvent and then dispersing it with a disperser. Dispersers for effective dispersion of colored pigments can use a variety of known dispersers, for example, paint mill (Eiger Mill) and the like.

The coloring pigments may include white, colored and black pigments, and the like, or may be used alone or in combination. Such pigments may be known inorganic or organic pigments, for example titanium dioxide, iron oxide pigments, carbon black, azo pigments, bengalas, phthalocyanine pigments, quinacridone pigments, pyrrolopyrrole pigments, perylene pigments, talc, Silica, calcium carbonate, barium sulfate, and zincated (zinc oxide).

If the amount of the pigment is too small, it is difficult to achieve the desired color sufficiently, on the contrary, if the content is too high, there is a problem of poor workability, stability, chemical properties, solvent resistance, etc., 1 to 15% by weight, or 5 to 15% by weight It may be included as a%, but is not limited thereto.

In the case of the pigment pigment dispersion, an aqueous solvent such as water may be used because it must be compatible with the first liquid containing the water-soluble resin. In addition, the coloring pigment can be effectively dispersed by adding a water-soluble dispersant.

In addition, a small amount of co-solvent may be included in order to increase the stability of the pigment pigment dispersion, for example, alcohols and cellulose-based solvents that are not a problem even if included in the water-soluble composition are used, and environmental problems and workability aspects It is preferable to use alcohols.

2. Eco-friendly organic coated color steel

The present invention also provides an environmentally friendly organic coated color steel sheet manufactured in a continuous plating line by the manufacturing method of the environmentally friendly organic coated color steel sheet.

As described above in Item 1, the eco-friendly organic coated color steel sheet produced by the method according to the present invention is water-soluble prepared by effectively blending and dispersing a colored pigment with an aqueous resin composition without containing harmful substances such as chromium or VOC. A color steel sheet is produced on a plating line using a colored paint composition.

According to another embodiment, the base steel sheet, and a color coating layer formed directly on the base steel sheet, containing a water-soluble resin and a color pigment; It includes, provides an environmentally friendly organic coated color steel sheet.

In the case of the conventional color steel sheet, most of the color coating layer is formed by using oil paint, and even the color steel sheet to which color is applied to the organic coated steel sheet is formed through a chromate treatment process or the like. As in the present invention, there is no color steel sheet which is environmentally friendly and has a color coating layer formed by coating a water-soluble resin composition directly on the resin steel sheet.

The eco-friendly organic coated color steel sheet of the present invention can be used in electrical and electronic products, etc. by satisfying the required physical properties of home appliance exterior materials by adjusting the coating thickness of the color coating layer to 7-8 μm. Compared to the steel sheet produced in CCL), the cost is low, and the economic efficiency is excellent, and since VOC is not generated, it is also environmentally advantageous.

In one example, a clear coating layer may be further formed on the color coating layer in the eco-friendly organic coated color steel sheet. The clear coating layer is a water-soluble color pigment is excluded from the water-soluble coating composition, for example, it can be prepared by applying and drying the first liquid for the production of the color coating layer.

The clear coating layer comprises a clear coating composition comprising 50 to 80% by weight of an aqueous resin composition containing 50% or more of a water-soluble polyolefin resin, 10 to 30% by weight of a rust preventive agent, and 0 to 10% by weight of an additive on the color coating layer It can be prepared by application and drying.

The base steel sheet is, for example, galvanized steel sheet (EG), galvanized steel sheet (GA), galvanized steel sheet (Galvanized steel sheet, galvanized steel sheet galvanized or zinc alloy) GI), preferably zinc or zinc alloy plated electrogalvanized steel sheet. Examples of the alloy plating include Zn-Ni, Zn-Fe, Zn-Mn, Zn-Cr, and Zn-Ni-Cr.

The coating thicknesses of the color coating layer and the clear coating layer are respectively 4-7 μm of the color coating layer, 1-4 μm of the clear coating layer, more preferably 5-6 μm of the color coating layer, 2-3 μm of the clear coating layer, and the whole. It is preferable that coating thickness is about 8 micrometers.

Eco-friendly organic coated color steel sheet according to the present invention can be used for home appliances such as TV (PDP, LCD), microwave oven, vacuum cleaner, office equipment.

Hereinafter, the present invention will be described in detail according to a preferred embodiment of the present invention. Evaluation methods used in the present examples and experimental examples are as follows.

1. Appearance: Visually determine the appearance of coating after film formation.

2. Gloss: Measure 60 ° gloss using the Gloss Meter.

3. Color: Measure the color difference with standard specimen after preparing reference specimen

4. Stability: Measure the stability of the coating agent over time

5. Corrosion Resistance: Cut the specimen to 90 X 150mm, seal the cross-section completely with OPP tape, and then use the white-blue part of the flat part and Ericsen 10mm extrusion part by ASTM-G170 under the salt spraying environment of 35 ℃, 5 wt% NaCl solution. Measurement of occurrence time (standard 240 hours)

6. Processability: Firstly evaluate the peeling of the coating film by peeling the scotch tape to the surface after bending the specimen 180 ° bending, and immersing the specimen in boiling water (more than 98 ℃) for 1 hour. The degree of peeling by the method is secondarily evaluated.

7. Chemical resistance: 3% by weight of Hcl and 3.5% by weight of NaOH solution was dropped on the surface of the steel sheet (Drop) to confirm the appearance change when removed after a certain time.

8. Solvent resistance: Rubbing test should be performed on the surface of the steel plate with 1Kg load of the cloth soaked with MEK (Methyl Ethyl Ketone), and there will be no surface condition change after 50 round trip tests.

9. High temperature, high humidity: The surface of the specimen was faced with 192 hours at 65 ℃ and 95% RH while pressing with 1Kg load.

10. Storage stability: A treatment was prepared and the liquid state was observed on a daily basis. Check for pigmentation or fading of colored pigments.

11. Hardness: The hardness of the coating surface is measured using a hardness tester

12. Workability: Check if there are any peculiarities or difficulties in forming the film on the steel plate by using the Bar Coater for Lab.

[Examples 1 to 7]

Preparation of the first liquid

In each example, an aqueous resin composition was prepared in a composition as shown in Table 1 below. 60 wt% of the prepared aqueous resin composition was mixed with 20 wt% of the composite antirust agent manufactured by Mosth and 5 wt% of other additives for surface adjustment to prepare a first liquid.

Preparation of the second liquid

20% by weight of pigment (Carbon Black pigment) was added to 65% by weight of water, and a liquid dispersant (Eiger Mill) was prepared by mixing 4% by weight of BYK's water-soluble dispersant, 1% by weight of TEGO's antifoam, and 10% by weight of ethylene glycol. ) To prepare a second liquid by dispersing in particle size specification NS7.0 or higher.

Preparation of Water-Soluble Colored Paint Composition

7% by weight of the second liquid is mixed while stirring the first liquid at 800 to 1000 rpm, and 8% by weight of water is mixed to prepare a water-soluble coating composition.

Preparation of Clear Paint Composition

70% by weight of the aqueous resin composition of the composition as shown in Table 1, 20% by weight of the composite antirust agent of Most, 5% by weight of other surface adjustment additives and 5% by weight of water were mixed with stirring at 800 rpm to prepare a clear coating composition.

Manufacture of eco-friendly organic coated color steel sheet

The water-soluble coating composition was applied to the electro-galvanized steel sheet by applying a roll coating method of 5 to 6 μm under a PMT 150 ° C. drying condition to form a color coating layer. Then, the clear coating composition was applied on a color coating layer 2 to 3㎛ by roll coating under PMT 150 ℃ drying conditions and then dried to form a clear coating layer to prepare a specimen.

TABLE 1 Aqueous resin composition

Experimental Example 1 Physical Properties Test of Examples 1-7 Specimen.

Corrosion resistance, hardness, workability and workability of the specimens of Examples 1 to 7 were measured, and the results are shown in Table 2 below.

 TABLE 2

Referring to Table 2, it can be seen that the color steel sheet produced according to the embodiment of the present invention exhibits excellent overall physical properties. In addition, when the content of the polyolefin is 50% or more, it was excellent in terms of corrosion resistance, hardness and workability, workability, it can be confirmed that the work stability is low when the pH is strongly alkaline.

[Examples 8 to 11]

Preparation of First Liquid and Second Liquid

60 wt% of the water-soluble resin composition according to Example 2, 20 wt% of the rust preventive agent, and 5 wt% of the additive were mixed to prepare a first liquid, and a second liquid was prepared in the same manner as in Examples 1 to 7.

Preparation of Water-Soluble Colored Paint Composition

While stirring the first liquid at 800 to 1000 rpm, the content of the second liquid was added differently as shown in Table 3 below, and the second liquid and the total amount of water were mixed to prepare 15 wt% to prepare a water-soluble coating composition.

Manufacture of eco-friendly organic coated color steel sheet

The water-soluble colored coating composition prepared above was applied to an electrogalvanized steel sheet in the same manner as in Examples 1 to 7 to form a color coating layer, and then a clear coating layer was formed to prepare a specimen.

Experimental Example 2 Physical Properties Test of Examples 8-11 Specimen.

Appearance, gloss, hiding power, stability, workability, chemical properties and solvent resistance of the specimens of Examples 1 to 7 were measured, and the results are shown in Table 3 below.

 [Table 3]

According to the results of Table 3, when the content of the colored pigment mixture is less than 5% by weight, hiding power is lowered, when it exceeds 15% by weight it can be seen that the workability, stability, chemical properties, solvent resistance and the like. Generally, when the content of the colored pigment mixture is more than 15% by weight, there is a problem in the degree of curing of the coating agent has been shown to reduce the overall physical properties.

[Experimental Example 3]

As shown in Table 4, the physical properties of the environmentally-friendly organic coated color steel sheet prepared according to Example 9 and a known color steel sheet was compared, and the results are shown in Table 5 below.

[Table 4]

[Table 5]

As shown in Table 5, the eco-friendly organic coated color steel sheet according to the embodiment of the present invention in the overall physical properties compared to conventional EGI anti-fingerprint coated steel sheet in corrosion resistance, processability, chemical resistance, solvent resistance, hiding power and high temperature and high humidity You can see that the performance is excellent.

In particular, the use of oil-based paints, which are currently used as exterior materials for home appliances, was able to achieve satisfactory results when compared to products produced in the color coating line (CCL).

Claims (8)

(i) 50 to 80% by weight of the aqueous resin composition; 10 to 30% by weight rust inhibitor; Preparing a first liquid by mixing 0-10 wt% of an additive and 1-10 wt% of water;
(ii) mixing a pigment, a co-solvent and a dispersant with an aqueous solvent, and then dispersing it with a disperser to prepare a second liquid;
(iii) mixing the first liquid, the second liquid and water to prepare a water-soluble colored paint composition; And
(iv) applying and drying the water-soluble colored paint composition on a steel sheet to form a color coating layer on a continuous plating line;
Manufacturing method of eco-friendly organic coated color steel sheet comprising a. The method of claim 1, wherein on the color coating layer prepared in step (iv),
(v) 50 to 80% by weight of the aqueous resin composition; 10 to 30% by weight rust inhibitor; And applying and drying a clear coating composition prepared by mixing 0 to 10 wt% of an additive to form a clear coating layer;
Further comprising, a method of manufacturing an environmentally friendly organic coated color steel sheet. The water-based resin composition according to claim 1 or 2, wherein the water-based resin composition is water-soluble or water-dispersible, with 50 to 100% by weight of polyolefin resin, 0 to 50% by weight of emulsion acrylic resin, and 0 to 50% by weight of polyurethane dispersion resin. Eco-friendly organic coating, which has an average particle diameter (D50) of 100 nm or less, a number average molecular weight of 5000 to 25000, a curing temperature of 120 to 180 ° C, and a pH of 7 to 11 Method of manufacturing colored steel sheet. The method of claim 1, wherein the pigment is contained in 5 to 15% by weight, eco-friendly organic coated color steel sheet. The method of claim 1, wherein the plating line is any one of an electro galvanizing line or a hot dip galvanizing line, and an alloyed hot dip galvanizing line. An environmentally-friendly organic coated color steel sheet manufactured in a continuous plating line by the method according to claim 1. delete delete