KR20060084170A - Color coating steel plate in roof material - Google Patents

Abstract

The present invention has a zinc or zinc alloy plating layer (2), chromate layer (3) and epoxy-modified or polyester-modified primer undercoat layer (4) on the base steel sheet (1), the number average molecular weight is 6,000 to 15,000, glass It contains a modified oil free polyester compound, an additive, a solvent, a wrinkle forming agent, and a pigment obtained by reacting two oil free polyester resins having a transition temperature (Tg) of 1 to 40 ° C. with an OH value of 25 to 50 and a typical melamine resin. It relates to a color coated steel sheet for roofing material comprising a top coat layer (5).

By forming wrinkles and / or irregularities on the surface, it shows excellent texture and beautiful aesthetics and is excellent for heat shielding as an exterior material for building roofing materials, so it is possible to keep the internal temperature constant without applying extra energy. Energy savings can be induced in the applied buildings.

Roofing material, prepainted steel

Description

Color coating steel plate in roof material}             

1 is a cross-sectional view of the color-coated steel sheet of the present invention.

2 is a comparative test result of the light reflectance between the pigment used in the present invention and a conventional pigment.

3 is an actual surface photograph of the color steel sheet of the present invention.

4 is an actual surface photograph of the colored steel sheet of the present invention formed into a metal tile.

5 is an actual surface photograph of a color coated steel sheet of the present invention having a clear coating layer to which metallic pigment is added.

Fig. 6 is a photograph of the actual surface of the color-coated steel sheet of the present invention in which a stucco pattern is pressed down on a clear coating layer with a double-sided embossing roll.

7 is a graph showing measurement results of reflectance using the near infrared spectrum of Example 1 and Comparative Example 1. FIG.

8 is a graph measuring surface temperatures of Example 1, Comparative Example 1, and Comparative Example 2. FIG.

The present invention relates to a color-coated steel sheet having a beautiful appearance for use in a building roofing material and excellent coating properties.

Conventional building roofing materials used natural asphalt shingles sheets with a beautiful appearance and rough texture, or a product sprayed with stone on hot-dip galvanized steel sheets pressed in the form of metal tiles, but were difficult to popularize due to their high price. Although the product lifespan is excellent and the metal sheet-type color coated steel sheet of economical price is widely used, it also causes the safety accidents such as fall and fall during roofing installation work due to the smoothness of the surface, Has been given away.

In addition, due to the characteristics of the roof material, the color of the deep color series is mostly applied, and thus the internal temperature of the building is increased due to the increase in the temperature of the roofing material itself due to the high infrared absorption rate of the solar light as compared to the pale color series.

Sunlight is composed of ultraviolet rays, visible rays, and infrared rays. Among them, long-wave infrared rays between 700 and 2500 nm have heat that is almost half of the solar energy, which is also called a hot ray. In addition, heat is emitted in the form of infrared rays in electronic products such as light bulbs. Therefore, in order to block external or internal heat, it is important to block near infrared rays and emit far infrared rays.

The choice of materials and the color of the surface of materials currently used for interior and exterior building materials has a significant impact on the internal temperature of buildings. Just as white clothes lower the body temperature than black clothes, the color of the exterior material may block or absorb external sunlight or heat. In addition, the roofing material made of metal has a higher heat transfer rate than natural roofing materials such as roof tiles and slits, so that external heat is conducted and radiated as it is, thereby increasing the internal temperature of the room. Therefore, in building roofing, the choice of materials and colors is an important factor in blocking external heat. With the proper choice of these materials and colors, energy costs can be significantly reduced by keeping the internal temperature constant. In addition, expansion and contraction of the exterior material due to heat causes deformation of the coating film of the color steel sheet, discoloration, gloss reduction, coating film cracks on the processed portion, and the like. Therefore, it can be seen that the heat shielding of the exterior material has the effect of saving energy and extending the life cycle of the product since the external life can be used to further extend the life of the product. In addition, the exterior material requires functionalities such as weather resistance, corrosion resistance, UV resistance, scratch resistance, and workability. In particular, in addition to such functionality, the exterior material, that is, the aesthetics of the surface texture, color, etc., are important factors in demand.

The present invention complements these problems to form wrinkles and irregularities on the surface to enable visual beauty as well as safety work due to the rough texture, using a pigment with excellent infrared reflectance for the metal roofing material excellent in heat shielding properties It is an object to provide a color coated steel sheet.

The above object of the present invention is a steel sheet (1); Zinc or zinc alloy plating layer (2); Chromate or non-chromate pretreatment layer 3; Epoxy modified or polyester modified primer undercoat layer (4); A modified oil free polyester compound obtained by reacting two oil free polyester resins having a number average molecular weight of 6,000 to 15,000, a glass transition temperature (Tg) of 1 to 40 ° C., and an OH value of 25 to 50, and a common melamine resin, It is achieved by providing a color coated steel sheet for roofing material comprising a top coat layer 5 containing an additive, a solvent, a wrinkle forming agent, and a pigment.

The wrinkle forming agent is a secondary amine is preferably 0.5 to 1.0 parts by weight of the top coat layer paint.

It may also optionally contain 0.5 to 3.0 parts by weight of organic or / and 0.5 to 1.0 parts by weight of inorganic filler in the topcoat.

The pigments include heat shield pigments, preferably 25 to 35 parts by weight in consideration of economical efficiency, workability, concealment rate, and pigment absorption, and especially the pigments of the deep color series are 45 to 55% Cr2O3 and 45 to 55% Fe2O3. It is preferable.

In addition, according to the demand of the top coat layer, the top layer clear layer (CLEAR) can also be added to the film layer. The paint of the clear coat layer may further contain any one or more of pigments of pearl and metallic series.

As the plated base steel sheet 1 used in the present invention, most of the well-known ones such as zinc-aluminum-silica alloy plated steel sheets and plated steel sheets subjected to electrolytic and hot dip galvanization can be applied. Stainless discs can also be used.

The pretreatment layer (3) is for improving the corrosion resistance and adhesion of primer (undercoat) paint to the steel plate, and an eco-friendly non-chromate layer is preferable, but the corrosion resistance is slightly lower than that of the existing chromate coating, so the demand is high. Known chromate or chromium trivalent pretreatments can be used as required.

The top coat forming the top coat layer 5 of the color coated steel sheet of the present invention is a PCM paint exhibiting a good texture on the surface of the coated film, and is designed to maintain excellent processability, weather resistance, UV resistance, corrosion resistance, and scratch resistance. By using polyester resin and melamine resin as a base, it is possible to selectively give one of the surface wrinkles and the surface feel, or the duplex to the surface of the coating film when forming the coating film. In order to create unevenness and / or wrinkles on the surface of the dry coating film 5 to induce visual interest on the surface of the coating film, a certain amount of pure amine was used as an anti-wrinkle agent of resins as an essential ingredient for the top coating, and to provide excellent heat shielding properties. In order to add heat shielding pigments and to improve the surface feel, optionally organic or / and inorganic fillers can be used.

PCM paints (Regular Polyester) resins, which are generally used for building materials, have branched functional groups such as hydroxyl groups and carboxyl groups in the backbone of the resin. Elongation of the coating film was extremely limited after the formation of the coating film because it had a network structure when crosslinking with melamine (eg, Hexa-Methoxymethyl melamine) resin used as a crosslinking agent (hardening agent). On the contrary, the flexible polyester coating resin used for home appliances has a very good elongation of the coating film because the main chain of the resin is a linear structure, but has a disadvantage of weak weather resistance, UV resistance, and corrosion resistance.

In order to supplement the shortcomings of such paints for building materials and to combine the processability, which is an advantage of household paints, to give the rough texture characteristic of the roofing material, the polyester main resin of the topcoat provides properties such as flexibility of the coating film and good surface wrinkle formation. Modified oil-free polyester in which two resins of oil-free polyester having a number average molecular weight of 6,000 to 15,000, a glass transition temperature (Tg) of 1 to 40 ° C, and an OH value of 25 to 50 were reacted with a common melamine resin. Compound is preferred.

The polyester resin is composed of Resin A and Resin B as shown in Table 1 below.

Molecular Weight OH value Tg A.V Synthetic Resin Resin A 6,000-10,000 35-50 35-40 ° 10 ↓ Iso Phthlic Acid, 2,2-dimethyl-1,3-propanediol (2,2-Dimethyl-1,3-Propanediol) Resin B 7,000-15,000 25-35 1 ~ 5 ° 10 ↓ 1,4-Dicarboxylic Acid, Phthalic Anhydride 2,2-Dimethyl-1,3-propanediol (2,2-Dimethyl-1,3-propanediol )

The melamine used as the crosslinking resin is preferably a methoxy or methoxy butoxy mixed melamine having a number average molecular weight of 300 to 1,000. When the butoxy melamine alone or a mixture of methoxy melamine and butoxy melamine is used, the compatibility with the polyester resin is drastically reduced, and the melamine is transferred to the upper portion of the paint, which may interfere with surface wrinkle formation or cause poor workability. Because it can.

Such crosslinked resin is preferably 3 to 10 parts by weight. If the melamine content is more than 10%, the wrinkled pattern is dense, and if the melamine content is less than 3%, the degree of curing decreases.

Commercially available RESIMINE 755 (SOLUTIA), RESIMINE 757 (SOLUTIA), RESIMINE 751 (SOLUTIA), CYMEL 1168 (CYTEL), CYMEL 1170 (CYTEL), CYMEL 232 (CYTEL), CYMEL 303 ( CYTEL).

Curing accelerators promote the crosslinking between polyester, a main resin, and melamine, a crosslinking resin, to increase the density. As a masked acid blocked with amine, p-toluene sulfonic acid, dininonylnaphthalene Sulfonic acid (Dinonylnaphthalene Sulfonic Acid), dodecylbenzenesulfonic acid (DDBSA, Dodesyl Benzene Sulfonic Acid) or unblocked dodecylbenzenesulfonic acid (DDBSA, Dodesyl Benzene Sulfonic Acid). In addition, epoxy masking sulfonic acid or epoxy resin masked sulfonic acid may be used. The amine is a material that can be dissociated by heat and may form wrinkles on the surface of the coating film together with the pure amine which is the above-described wrinkle forming agent when the top coat is baked. In this case, the amount of the curing accelerator used is preferably 0.04 to 0.1 parts by weight.

If it is less than 0.04%, it is difficult to secure the degree of curing, and if it exceeds 0.1%, the pattern becomes dense.

Pure amine floats on the surface of PMT 170 ~ 190 ℃ during the hardening process of coating film coated with the main component that controls the size of wrinkle formation in addition to its role as an auxiliary curing accelerator to promote the crosslinking of resin constituting the topcoat. By proceeding faster than the internal curing rate of the hardening by the volume reduction due to the difference between the surface and the internal curing rate is to form a wrinkle on the surface gradually. As the amines used as such co-promoters, all primary, secondary and tertiary amines can be used, of which secondary secondary amines are most preferred. This is because primary amines bring about a change in color such as yellowing in the coating film, and tertiary amines bring about strong shrinkage on the surface, but secondary amines have no yellowing and proper surface shrinkage. Of the secondary amines, triethylamine is preferred. The amount of the amine used is preferably 0.5 to 1.0 parts by weight. If the amount is less than 0.5 parts by weight, the surface of the coating film and the internal curing are simultaneously formed, so that the formation of wrinkles is difficult. If the amount is more than 1.0 parts by weight, the coating film hardly occurs so that the soft texture of the surface of the coating film is difficult to be exhibited. Since the degree of formation of wrinkles varies depending on the adjustment amount, it is preferable to appropriately adjust the addition amount according to the purpose of use.

As the pigment used in the colored top coat of the present invention, general organic and inorganic pigments used in PCM paint can be used without limitation, but in order to impart heat shielding, which is one of the main characteristics of the present invention, according to the demand of the demand. By applying a special pigment having excellent infrared reflectance, it becomes an important factor to keep the room temperature constant by blocking heat by absorption, conduction and radiation of external infrared rays.

Such thermal barrier pigments are currently commercially available and include thermal barrier pigments from Ferro (USA), Shepherd (USA) and Isihara (Japan). Table 2 shows the solar energy reflectance of each pigment for the typical thermal barrier pigments of Ferro, USA.

Kind of pigment (No of commercial pigment) Solar Ref Yellow (V-9415) 66.5% Golden (10415) 58.0% Brown (10364) 39.2% Green (V-9248) 30.0% Light blue (V-9250) 29.2% Red (V-13810) 39.0% Black (V-799) 25.1% Black (10203) 27.4%

Fig. 2 shows the results of comparing the solar energy reflectances of the above assay (V-799) and the conventional assay. The ordinary black can absorb only heat but hardly reflect the heat, but the pigment used in the present invention reflects 60% or more of infrared rays, indicating that the absorption is very low. This difference indicates an internal temperature difference, and when the heat shield pigment is used, the internal temperature can be cooled.

The heat shield pigment is preferably 25 to 35 parts by weight. If it is less than 25 parts by weight, the heat shielding function is insufficient and the concealment rate is lowered. If it exceeds 35 parts by weight, it is economically burdened and the oil absorption of the pigment is increased, resulting in poor paint production and paintability.

In particular, heat shielding is very important in the deep color (black) series that is frequently used as the color of the roofing material. In the present invention, heat shielding pigments used for black roofing materials include Cr2O3 and Fe2O3, each content of 45% to 55% Cr2O3, 45% to 55% Fe2O3.

In addition to heat shielding pigments used in top coats, when the clear is additionally coated, pearl particles or metallic particles may be additionally used to show the appearance beautifully.

And in order to make the surface unevenness even more, 0.5-3.0 parts by weight of organic filler and / or 0.3-1.0 parts by weight of inorganic filler may be optionally added to the top coat as needed. The organic filler is a stable material and has excellent durability, chemical resistance, lubricity and high hardness to form the physical and chemical performance of the coating film. The organic filler that can be used is selected from plastic fillers (called nylon (NYLON) fillers) such as polyacryl, polyamide, polypropylene, polyethylene and the like. The organic filler is a stable material and has excellent durability, chemical resistance, lubricity and high hardness, thereby improving the physical and chemical performance of the coating film.

When the added organic filler reaches 100 ° C or more during the baking process of the paint, a slight melting process is performed on the surface of the solid organic filler, thereby fusion occurs at the surface of the binder (resin) and the organic filler. It forms irregularities that feel the feel of the material. In this case, when the colored organic filler is added as necessary, the visual sensitivity of the surface may be variously expressed according to the color of the selected organic filler. And if you want to simply give the characteristics of the irregularities without affecting the color of the existing paint, you can use a transparent organic filler. Therefore, transparent or colored organic fillers may be used alone or in combination for application purpose. For this reason, the degree of irregularities is also changed depending on the amount of addition of the organic fillers and the selection of the particle size. The range of% is suitable, More preferably, it is 1-2%. If the added organic filler is less than 0.5%, the effect of unevenness is insignificant, and if it exceeds 3.0%, the weather resistance becomes weak. In consideration of the dry coating thickness of 15 to 30㎛, it is preferable to select and use a transparent or colored spherical organic filler having a particle size of about 20 to 40 microns.

Inorganic fillers generally use amorphous coated silica known as a matting agent, and in the present invention, the inorganic filler is mainly used for improving gloss stability and workability, in addition to providing surface feel, rather than matting purpose.

Such silica is 0.3 ~ 1.0% by weight is suitable, when used more than 1% wrinkles less bone gap, the bone gap becomes visually messy.

In the present invention, such organic and inorganic fillers may be optionally used alone or mixed as needed, and organic fillers may be selected and used as colored or / and colorless as described above. By the addition of such organic inorganic filler, it is possible to further obtain a coating film having a uniform three-dimensional feeling and a tactile effect such as a natural material on the entire surface of the coating film.

It is preferable that the top coat of the deep color for roofing material of the present invention has a composition ratio shown in Table 3 below.

(Content based on 100% (wt) of solid content per raw material)

division ingredient Content (weight ratio)%  Suzy Polyester resin A 20-40 Polyester resin B 10-30 Melamine resin 3-10 Fee Organic Pigments 2-5 Inorganic pigments 5-35 Heat shield pigment 25-35 filler Organic filler 0.5-3.0 Inorganic filler 0.3-1.0 additive Deforming Agent 0.1-1.0 Leveling agent 0.1-1.0 Curing accelerator 0.04-0.1 Color Separation Agent 1.0-3.0 Antiblocking Agent 0.1-1.0 Solvent Hydrocarbon 15-25 Ester (Ester system) 15-25 Acetate 15-25 Wrinkle Forming Agent Secondary amine 0.5-1.0

As described above, the wrinkles formed by the amine and the uneven wrinkles on the surface of the coating film and the three-dimensional appearance of the uneven shape due to the irregularities caused by the organic and inorganic fillers are relatively light scattering, resulting in the glossiness of the coating film. Or less). In general, an excessive amount of matting agent is used in the paint to about 7-10% (wt%). In this case, the PVC (Pigment Volume Content) value of the matting agent is high for the resin. On the other hand, the coating film of the color coated steel sheet of the present invention has a natural matting effect due to the natural matting effect due to wrinkle formation and / or oil absorption of heat shielding pigments. It is possible to further improve physical properties than the ultra matt coating film.

UV fillers may be added to the colored or transparent polyester based paints of the present invention in order to enhance UV resistance as necessary. The solvent is selected from hydrocarbon, ester and acetate as much as possible for uniform surface wrinkle prevention and roll mark prevention.

Hereinafter will be described with respect to the road.

The bottom coat used for material adhesion may be a polyester bottom coat, an epoxy bottom coat, an acrylic bottom coat, an acrylic primer, or a modified bottom coat. The commercially available polyester bottom coats are manufactured by Korea Chemical Co., Ltd. FP 1800 series, Y005 series of Samsung Precision Co., Ltd. and HDP 600 of DCC Co., Ltd.

In addition to its basic physical properties such as general corrosion resistance and strengthening adhesion between top and embossed steel sheets, the undercoat gives elongation to provide sufficient buffering action at the interface between the material and the top coat. Rather than being absorbed by the undercoat. Anticorrosive pigments should be used for the corrosion resistance of the undercoat, and like the top coat, it can be used without limitation for organic and inorganic pigments used for PCM paints. Anti-rust pigments may optionally be used as toxic pigments or non-toxic anti-rust pigments free of lead or chromium. Conventional rust preventive pigments include Red Leed, Zinc Potassium Chremate, Zinc Tetra Chromate, and Strontium Chromate containing lead and chromium. Typical pigments include barium metaborate, barium metaborate, zinc molybdate, zinc zinc molybdate, zinc zinc phosphate and zinc phosphate. Phosphate (Aluminum Triphosphate), silicate based calcium borosilicate (Calcium Borosilicate), Phosphosilicate (Phosphosilicate), Calcium Ion-exchanged Silicate, Magnesium Ion-exchanged Silicate, etc. There is this.

3 is an actual surface photograph of the color steel sheet of the present invention. 4 is an actual surface photograph of the colored steel sheet of the present invention formed into a metal tile.

In the color coated steel sheet of the present invention, a clear coating layer for forming the uppermost coating layer may be added according to the demand of the demand. CLEAR coating layer is composed of constituent components except the pigment based on top coat, and in order to give a rougher texture than top coat on the surface of coating as well as adhesion and high weatherability and processability with top coat. And / or some metallic pigments may be added. FIG. 5 is an actual surface photograph of a color coated steel sheet of the present invention having a clear coating layer to which a metallic pigment is added.

In addition to the addition of such a clear coating layer, a double-sided embossing roll engraved with an uneven pattern such as a stucco may be pressed down on a steel sheet to form a three-dimensional pattern on the surface to further add designability.

In addition, an object of the present invention is a zinc or zinc alloy plated layer (2) electroplated or hot-dipped on the base steel sheet 1, chromate or non-chromium at a line speed of 50 to 120 mpm Acid treatment and drying at 60-140 ° C. to form a pretreatment layer 3; Forming a undercoat (4) on the pretreatment layer; And modified oil-free polyesters obtained by reacting two kinds of resins of oil-free polyesters having a number average molecular weight of 6,000 to 15,000, a glass transition temperature (Tg) of 1 to 40 ° C., and an OH value of 25 to 50, and a common melamine resin. Color coating for roofing material comprising coating a top coat comprising a resin, an additive, a solvent, a wrinkle forming agent, and a pigment, and heating and drying at PMT 190 to 240 ° C. to form the top coat layer 5. By providing a steel sheet.

In addition, a clear paint layer may be coated on the top coat layer 5 to add the clear coat layer 6. In addition, the method may include applying an embossed three-dimensional pattern to the top coat layer 5 or the clear coat layer using a double-sided emboss roll. Fig. 6 is a photograph of the actual surface of the color-coated steel sheet of the present invention in which a stucco pattern is pressed down on a clear coating layer with a double-sided embossing roll.

Of course, it can be used as a base plate, such as a normal copper plate or a stainless plate, in addition to the plated base plate. On the substrate, a chromate treatment was applied to the surface by a roll coating method with a line speed of 50 to 120mpm in a continuous coating line, dried at a temperature of 60 to 140 ° C, and a chromate layer of 20 to 80 mg / m ² . (non-chromate layer 100-250 mg / m 2) is formed thereon to form polyester rust preventive coating and colored polyester-based top coat.

The coating method includes a conventional floor coating method in addition to the roll coating method.

Color coated steel sheet for roofing material of the present invention has a thickness (D.F.T) of each layer constituting the coating film cross section is 15 ~ 30㎛ top coat. It is preferable that it is 4-10 micrometers of undercoat films, and 10-25 micrometers of clear coating films. If the thickness of the top coat is 15 μm or less, the surface wrinkles are finely formed. If the thickness is 30 μm or more, it is disadvantageous in terms of economic efficiency. peak metal temperature) Dry by heating to 190 ~ 240 ℃.

Hereinafter, the present invention will be clearly described by Examples and Experimental Examples, but the present invention is not limited by the following Examples.

Specimen standards and coating conditions used in the examples are as follows and% means weight%.

Coil Standard: W (Width) 1040 × T (Thickness) 0.5mmGI (Hot-Plated Steel Sheet)

-Dry coating thickness: 10㎛ below, 15㎛ above

-Viscosity of work coat of paint (25 ℃, ＃ 4 Ford cup) 40 seconds

-Top coat working viscosity (25 ℃. ＃ 4 Ford cup) 80 seconds

Roll coating method: Roll reversing

-Haedo: Korea Chemical Co., Ltd. FP 1800 series

Example 1

Base steel sheet, zinc alloy plating layer, chromate layer, polyester modified primer undercoat layer, oil-free polyester compound resin 42 parts by weight, melamine resin 5.6, matting agent 0.45 parts by weight, alkyl epoxy modified with color separation inhibitor epoxy) 2.00 parts by weight, acry resin-based 0.42 parts by weight of antifoaming agent, 0.06 parts by weight of unblocked dodesylbenzene sulfonic acid as curing accelerator, 0.17 parts by weight of PTEE and PE wax polymer as antiblocking agent, trimethyl as a pattern forming agent A coating of a top coat layer comprising 0.70 parts by weight of amine, 18.8 parts by weight of cellosolve acetate, xylene, and acosolve diffe as a solvent, and a black heat shield pigment (Cr 2 O 3 and Fe 2 O 3 in a ratio of 1: 1). Color coated steel sheet was produced.

Comparative Example 1

In the color-coated steel sheet of Example 1, instead of the heat shield pigment, a color steel sheet to which a normal black pigment was applied was produced.

Comparative Example 2

In the color-coated steel sheet of Example 1, a steel sheet was added to which a pigment of white (TiO 2) was added instead of the heat shielding pigment.

Experimental Example 1

The solar energy reflectances of Example 1 and Comparative Example 1 were investigated by using a near-infrared spectrum. 7 shows the result.

As shown in FIG. 7, conventional pigments have almost no light reflection, but the steel sheet of Example 1 using a heat shield pigment showed a reflectance of more than 60%.

Experimental Example 2

In Example 1 and Comparative Example 1, the irradiation amount of total light energy and the amount of light reflection thereon were specified on both steel sheets by using an ultraviolet-visible-infrared spectrum (UV-Vis-NIR Spectrum). From the results, total solar reflectance (TSR) was shown. TSR is represented by Equation 1 below to indicate the ability to shield heat by reflecting sunlight.

TSR% = ∫E (λ) R (λ) dλ / ∫E (λ) dλ

In the above formula, E (λ) represents the total spectrual irradiance of the spectrum and R (λ) represents the optical reflectance.

Example 1 showed 21.5%, and Comparative Example 1 showed 4.7%, showing an excellent effect on total solar energy reflectance.

Experimental Example 3

The steel sheet of Example 1, Comparative Example 1 and Comparative Example 2 was irradiated with time using a far infrared lamp to check the change of surface temperature.

8 shows the result. Example 1 coated with a heat shield pigment had a higher surface temperature than Comparative Example 2 of the white series, but a lower surface temperature with a difference of about 23 ° C. compared with Comparative Example 1 using a conventional pigment.

Experimental Example 4

Table 4 below is a result of comparing the coating properties of Example 1 and Comparative Example 1 of the present invention.

division Example 1 Comparative Example 1 1. Workability  ○  ○ 2. Surface wrinkles and / or irregularities  ○  ○ 3. Solvent resistance 75 75 4. Pencil Hardness H H 5. Processability T-bending 1T 1T s-cupping  ○  ○ 6. Adhesiveness 100/100 100/100 7. IMPACT  ○  ○ 8. Chemical resistance 5% NaOH  ○  ○ 5% HCl  ○  ○ 9.Corrosion resistance (500hr)  ○  ○ 10. UV resistance 500hr 0.65 0.72 11. Weather resistance 500hr 0.44 0.7

◎: very good, ○: good, △: normal, ×: poor

Workability of -1: Pick up in roll roll coating

Degree of surface wrinkles and / or irregularities of the dry coating film

Solvent resistance of -3: M.E.K rubbing

-4 Pencil Hardness: Using the `` Uni Pencil '' from Mitsushi-shi, Japan

-5 machinability: T-bending, cracking state after square cupping

-6 adhesion: 6mm cross cut

-7, Impact: 1 / 2φ × 1㎏ × 50cm

Chemical Resistance of -8: Color Difference between Pre-Test Specimen and Test Piece Soaked in 5% NaOH, 5% HCl Solution for 24 Hours

Corrosion resistance of -9: salt spray test (S.S.T) 35 ° C. 5% NaCl, 500 hr

U.V resistance of -10: Measured ΔE value after measuring 20w × 20cm × 500hr

Weatherability of -11: Measured ΔE value after 500 hours of Xenon arc lamp

As shown in the above table, the color-coated steel sheet of the present invention has a remarkably superior reflectance compared to the comparative example, which is excellent in heat shielding properties, and in terms of its appearance, functional aspects, that is, corrosion resistance, weather resistance, and workability. Equal or better effect

The color coated steel sheet for roofing material of the present invention exhibits excellent texture and beautiful aesthetics by forming wrinkles and / or irregularities on the surface, and has excellent heat shielding as an exterior material for building roofing materials so that the internal temperature is constant without applying additional energy. It is possible to maintain energy efficiency, which can induce energy saving effect in buildings with metal roof materials.

Claims (10)

Zinc or zinc alloy plating layer (2), chromate layer (3) and epoxy-modified or polyester-modified primer undercoat layer (4) on the base steel sheet (1), the number average molecular weight is 6,000 to 15,000, and the glass transition temperature ( Topcoat film containing modified oil-free polyester compound, additive, solvent, wrinkle forming agent and pigment which reacted with two kinds of oil-free polyester resin having Tg) of 1 to 40 ° C and OH value of 25 to 50 and normal melamine resin Color coated steel sheet for roofing material including layer (5) According to claim 1, wherein the wrinkle forming agent is a secondary amine color coated steel sheet for roofing, characterized in that 0.5 to 1.0 parts by weight based on the top coat The color coated steel sheet for roofing according to claim 1, wherein the top coat layer further comprises any one or more of 0.5 to 3.0 parts by weight of an organic filler and 0.5 to 1.0 parts by weight of an inorganic filler with respect to the top coat. The color coated steel sheet for roofing according to claim 1, wherein the pigment comprises 25 to 35 parts by weight of heat-shielding pigment based on the top coat paint. The color coated steel sheet for roofing materials according to claim 4, wherein the heat-shielding pigment is a black pigment of 45-55% Cr2O3 and 45-55% Fe2O3. The color steel sheet for roofing materials according to claim 1, wherein the top coat layer further comprises a clear coat layer. The color steel sheet for roofing materials according to claim 6, wherein the paint of the clear coating layer further comprises at least one of pearl and metallic pigments. Zinc or zinc alloy plated layer (2) electroplated or hot-dipped galvanized steel sheet (1), chromate or non-chromate treatment at a line speed of 60 ~ 120 mpm and 60 ~ 140 ℃ Drying to form a pretreatment layer 3; Forming a undercoat (4) on the pretreatment layer; And modified oil-free polyester resins and additives in which an oil-free polyester resin having a number average molecular weight of 6,000 to 15,000, a glass transition temperature (Tg) of 1 to 40 ° C, and an OH value of 25 to 50 is reacted with a common melamine resin. , A coating method of a coating material containing a solvent, a wrinkle forming agent, a pigment, and heated and dried at PMT 190 ~ 240 ℃ to form a top coat layer (5) comprising the step of forming a color coated steel sheet for roofing. The method of manufacturing a color coated steel sheet for roofing material according to claim 8, further comprising forming a clear coating layer on the top coat layer. 10. The method of claim 8 or 9, further comprising the step of providing an embossed three-dimensional pattern by using a double-sided embossing roll on the top coat layer or the clear coat layer surface, characterized in that the manufacture of color steel sheet for roofing Way

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