KR100349085B1 - Coated steel plate - Google Patents

Abstract

The present invention relates to a coated steel sheet having a new concept of design and functionality exhibiting excellent physical properties while avoiding the monotony of the surface of a conventional general PCM coated steel sheet, and provides a visual three-dimensional impression on a plated zinc or zinc alloy plated steel sheet. In addition, it provides a color-coated steel sheet that exhibits excellent physical properties (processability, weather resistance, UV resistance, scratch resistance) as well as an environmentally-friendly appearance that is similar to natural materials such as stone, wood, and fiber as textures upon contact. do. The main structure is a zinc or zinc alloy plating layer (2), chromate layer (3) and epoxy-modified or polyester-modified primer undercoat layer (4) are sequentially formed on the base steel sheet (1), the main resin is poly A coating material composed of an ester resin, a crosslinking agent, a melamine resin, a curing accelerator, other additives, a solvent, and the like is coated on the undercoat layer 4 to form a top coat layer 5, and to form irregularities on the surface of the top coat dry film. Among the components constituting the top coat layer 5, 0.5 to 3 parts by weight of organic or / and 0.5 to 1.0 parts by weight of an inorganic filler and / or a wrinkle forming agent is 0.5 to 3.0 parts by weight of the top coat. It further essentially comprises a pure amine, preferably a secondary amine.

Description

Coated steel plate

The present invention relates to a color steel sheet having excellent design characteristics, and more particularly, to form wrinkles and / or irregularities on the surface of the steel sheet to selectively apply one of surface wrinkles and surface feel, or a double, processability and weather resistance. It relates to a color coated steel sheet having a coating film having excellent physical properties such as UV resistance.

The general modified polyester PCM steel sheet, which is currently used for interior and exterior building materials, has a plain appearance due to the smoothing of the surface from the design side, and general gloss preference in selecting the glossiness of the surface to prevent glare. For most products, matte is applied rather than glossy. In order to exhibit such a matting effect, a matting agent is generally added when the paint is prepared, but the more the matting agent is used, the lower the general gloss and general properties such as processability, weather resistance, UV resistance, and corrosion resistance.

On the other hand, in the case of PCM steel sheet for home appliances, wrinkles are formed on the surface of some products to give designability, but for the high processability, which is characteristic of PCM steel sheet for home appliances, linear polyester paint is used. If the line speed is 70mpm or more, the surface wrinkles are not formed properly and the productivity is lowered.They are not used for construction materials that require productivity and weather resistance due to their weak weather resistance, UV resistance, corrosion resistance, scratch resistance, etc. It is true.

Therefore, the present invention has been proposed in view of the above problems, and the present invention is to provide a color coated steel sheet for building materials having a three-dimensional and characteristic surface in place of the existing smooth surface in zinc or zinc alloy plated steel sheet. have.

Another object of the present invention is to provide a color coated steel sheet for building materials having an environmentally friendly appearance that feels similar to natural materials such as stone, wood, and fiber.

Still another object of the present invention is to provide a color coated steel sheet for building materials having both functionality and designability by having excellent physical properties such as workability, weather resistance, UV resistance, corrosion resistance, scratch resistance, etc. together with the designability of the new concept described above. Is in.

1 is a cross-sectional view of the coating film of the color-coated steel sheet according to the present invention

The present invention to achieve the above object,

Zinc or zinc alloy plating layer, chromate layer and epoxy-modified or polyester-modified primer undercoat layer are sequentially formed on the steel sheet,

The main resin is a polyester resin, the crosslinking agent is a melamine resin, and a resin composed of a curing accelerator, other additives, a solvent, and the like is coated on the undercoat layer to form a top coat layer, but to form irregularities on the surface of the top coat layer. The top coat constituting the top coat layer 5 provides a color coated steel sheet for construction materials, which comprises essentially 0.5 to 3 parts by weight of organic or / and 0.5 to 1.0 parts by weight of an inorganic filler with respect to the top coat.

In addition, the present invention is a top coat component constituting the top coat layer to form a wrinkle on the surface of the dry coating film to give a visual effect to the appearance of the steel sheet as a curing accelerator of polyester resins and melamine resins and top coat as a wrinkle forming agent It provides about 0.5 to 3.0 parts by weight of a pure amine, preferably secondary amine is essentially a color-coated steel sheet for building materials characterized in that it further comprises. The amine causes a difference in the curing rate inside and outside the coating film during baking of the top coat, thereby forming wrinkles on the top coat surface.

In addition, the present invention provides a color coated steel sheet having only wrinkles on the surface of the coating film. In this case, the coating material as a wrinkle forming agent in addition to the existing curing accelerator added to promote the curing of the polyester resin and melamine resin as a component of the top coat. By providing essentially 0.5 to 3.0 parts by weight of a pure amine, preferably secondary amine to provide a color coated steel sheet for building materials in which only wrinkles are formed on the surface of the dry coating film.

On the other hand, the color coated steel sheet for building materials of the present invention is the oil-free polyester of the polyester resin has a number average molecular weight of 10,000-30,000 and a glass transition temperature (Tg) of -5 ~ 45 ℃, OH value of 40 ~ 90 It is a modified oil free polyester compound which reacted the normal sulfur-free polyisocyanate, It is characterized by the above-mentioned.

In addition, the present invention is p-toluene sulfonic acid (Toluene Sulfonic Acid), Dinonylnaphthalene Sulfonic Acid (Dnonylnaphthalene Sulfonic Acid) or dodecylbenzene sulfonic acid (DDBSA, Dodesyl Benzene Sulfonic Acid) Provided is a color coated steel sheet for building materials, including).

In the color coated steel sheet for construction materials according to the present invention, it is preferable that the thickness of each layer constituting the cross-sectional view of the coating film is 12 to 30 µm in the upper coat, 4 to 10 µm in the coat, 20 to 80 mg / m 2 in the chromate layer, and 15 to 23 µm in the plating layer. Do.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 is a view schematically showing the cross-sectional structure of the color-coated steel sheet according to the present invention. Referring to the drawings, the plated base steel sheet 1 is applicable to most of the known steel plate, such as zinc-aluminum-silica alloy molten plated steel sheet, electroplated and hot dip galvanized plated steel sheet.

The chromate layer is for improving the corrosion resistance of the steel sheet, the adhesion of the primer (lower coating material) to the steel sheet, and the coating type chromate layer is preferable.

The top coat forming the top coat layer 5 constituting the top layer 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 has excellent workability, weather resistance, UV resistance, corrosion resistance, and scratch resistance. By using polyester resin and melamine resin designed to be maintained as a base, it is possible to selectively give one of surface wrinkles and surface feel, or double, to the surface of the coating film when forming the coating film, thereby improving the functionality and the beautiful surface appearance. It is characterized by satisfying at the same time.

That is, the present invention is an essential component of the top coat in order to form unevenness and / or wrinkles on the surface of the dry coating film 5 to cause visual interest on the surface of the coating film. Optionally includes an amount of pure amine.

First, the filler as the first essential component added to the top coat of the present invention, in order to give a three-dimensional appearance of the concavo-convex shape to the dry coating, 0.5 to 3.0 parts by weight of the organic filler and / or 0.5 to 1.0 parts by weight of the inorganic filler Add to The organic filler to be used is selected from plastic fillers (called nylon (NYLON) fillers) such as polyamide, polypropylene and polyethylene. Amide is a stable material with excellent durability, chemical resistance, lubricity and high hardness, which improves the physical and chemical performance of coatings.

The added amide has a slight melting process on the surface of solid amide when PMT reaches over 100 ℃ in the baking process of the paint, thereby fusion at the surface of binder (resin) and amide. The unevenness of the material feel is formed. At this time, if the colored amide is added as needed, the visual sensitivity of the surface can be variously expressed according to the color of the selected amide. If you want to give the characteristic of irregularities only without affecting the color of the existing paint or the pattern of the patterned transfer coating, use transparent amide, and use it for the coherent color change or transfer pattern of the paint. If you want to add texture with visual coloring, you can use colored amides. Therefore, transparent or colored amides may be used alone or in combination for the purpose of application, and the degree of irregularities is also varied depending on the amount of polyamide filler added and the particle size selected. Properly mix and use within the range. If the polyamide filler to be added is 0.5% or less, the effect of unevenness is weak, weather resistance is weakened at 3% or more, more preferably in the range of 1 to 2%.

In consideration of the dry coating thickness of 15 to 30 µm, it is preferable to select and use a transparent or colored spherical amide having a particle size of about 20 to 40 microns.

Inorganic fillers generally use amorphous coated silica, known as a matting agent, in the case of the present invention is used to improve gloss stability and workability, rather than the purpose of matting.

In the present invention, such organic and inorganic fillers may be selectively used alone or mixed as needed, and organic fillers may be selectively used in color and / or colorless as described above.

By the addition of such organic and inorganic fillers, it is possible to obtain a uniform three-dimensional appearance and a feel-like coating film on the entire surface of the coating film.

Next, pure amine, which is a wrinkle forming agent, will be described as the second essential component added to the top coat to form wrinkles on the surface of the coating film. Pure amine acts as an auxiliary curing accelerator to promote the crosslinking of the resin constituting the top coat. The pure amine floats to the surface at about 170 ~ 190 ℃ of PMT during baking of the coated coating film. By progressing the curing rate faster than the internal curing rate is to form a wrinkle on the surface gradually by volume reduction according to the difference between the surface and the curing rate.

As the amines used as such co-promoter (wrinkle forming agent), both primary, secondary and tertiary amines can be used, of which secondary secondary amines are preferred. The reason for this is that primary amines cause a change in color such as yellowing in the coating film, and tertiary amines cause strong shrinkage on the surface, while secondary amines bring no yellowing and proper surface shrinkage. Because.

When the amount of the amine used is insufficient, the surface of the coating film and the inside of the coating are hardened at the same time, and wrinkles hardly occur. When the excessive amount is used, the coating film hardens so rapidly that it is difficult to exhibit the soft texture of the coating film surface. Properly adjusting the added amount in consideration of the characteristics, the degree of the surface wrinkles are formed, and thus can be expressed differently with the visual three-dimensional feeling. The amount of pure amine added should be at least 0.5 parts by weight based on the top coat, preferably 0.5 to 3.0 parts by weight.

Hereinafter, other components constituting the topcoat of the present invention will be described.

Resin for PCM paint (Regular Polyester), which is generally used for building materials, has branched functional groups such as hydroxyl group and carboxyl group in the backbone of the resin. The 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 (curing agent) of the coating film. 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 weaknesses in weather resistance, UV resistance, and corrosion resistance.

In order to compensate for such drawbacks, the main resin of the topcoat has a number average molecular weight of 10,000 to 30,000 and a glass transition temperature (Tg) of -5 to 45 ° C. in order to impart physical properties such as flexibility of the coating and to form a good surface wrinkle. It is preferable to use a compound prepared by reacting an oil-free polyester polymer resin having a OH value of 40 to 90 with a conventional sulfur-free polyisocyanate compound.

The polyisocyanate serves to partially compensate for physical properties such as weather resistance, UV resistance, corrosion resistance, etc. by reacting a portion of the polyester main chain substituted with a branched OH group (urethane bond). Isocyanate compounds that can be used include hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, 2,4,6-triisocyanatetoluene and similar properties. Can be applied.

Next, the melamine used as the crosslinking resin is preferably a methoxy type or methoxy butoxy mixed melamine having a number average molecular weight of 300 to 1,000. When butoxy melamine alone or a mixture of methoxy melamine and butoxy melamine is used, the compatibility with the polyester resin is drastically reduced, and melamine is transferred to the upper portion of the paint, which hinders the formation of surface wrinkles or causes poor workability. Because you can. Commercially available materials include RESIMINE 755, RESIMINE 757, RESIMINE 751 (manufactured by SOLUTIA), CYMEL 1168, CYMEL 1170, CYMEL 232 (manufactured by CYTEL).

The curing accelerator constituting the topcoat is used to increase the density of the coating film by promoting crosslinking between the main resin polyester and the crosslinking resin melamine, and it is preferable to use an acid masked by blocking with an amine. Typically, p-toluene sulfonic acid (Toluene Sulfonic Acid), dinonylnaphthalene sulfonic acid (Dinonylnaphthalene Sulfonic Acid) dodecylbenzene sulfonic acid (DDBSA, Dodesyl Benzene Sulfonic Acid) and the like are used. 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 described above when the top coat is baked.

As the colored or transparent polyester-based top coat of the present invention, organic and inorganic pigments used in PCM paints can be used without limitation, and UV fillers may be added as necessary to enhance UV resistance.

As a solvent, it is selected from hydrocarbon type and ester type as much as possible for uniform surface wrinkle prevention and roll mark prevention.

It is preferable that the top coat of this invention has the following composition ratios.

Table 1

division ingredient Content (weight ratio)% Suzy Polyester resin 25-40 Melamine resin 4-10 Fee Organic Pigments 2-5 Inorganic pigments 5-35 filler Organic filler 0.5-3.0 Weapon filler 0.5-1.0 additive Deforming Agent 0.5-1.0 Leveling agent 0.5-1.0 Curing accelerator (including auxiliary accelerator) 1.0-6.0 Solvent Hydrocarbon 15-25 Ester (Ester system) 15-25

The uniform surface wrinkles on the surface of the coating film and the three-dimensional appearance of the irregularities in the form of wrinkles formed by amines and irregularities by organic and inorganic fillers, which have been described so far, result in relatively light scattering, resulting in a glossiness of the coating. 20% 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 physical properties such as scratch resistance are reduced, whereas the coating film on the color coated steel sheet of the present invention can further improve the physical properties of the conventional matt or ultra matt coating without using a matting agent.

Next, the following description will be given.

The material used for the adhesion of the material may be epoxy primer, polyester primer, acrylic primer, or a modified primer thereof. Commercially available, polyester primer is 8600 manufactured by Construction Chemical Co., Ltd. There are 8400 series of Construction Chemical Co., Ltd. as a series and an epoxy modified primer. At this time, the physical properties imparted to the undercoat, in addition to general corrosion resistance, which is the basic property of the undercoat itself, and strengthening the adhesion between the top and the plated steel sheets, are provided with an elongation to sufficiently buffer at the interface between the top and the top of the coating. The crack does not develop to the top coat layer and serves to be absorbed by the bottom coat layer. As the topcoat, the organic and inorganic pigments used in PCM paint can be used without limitation.

As a result of applying the paint of such characteristics to the zinc or zinc alloy plated steel sheet, as well as natural surface materials such as stone, wood, fiber, etc. A color-coated steel sheet for building materials having excellent functionality as well as an environmentally friendly emotional appearance with a similar feel was obtained.

On the other hand, in the production of color-coated steel sheet according to the present invention, the chromate treatment in the line speed of 60 ~ 100mpm on the zinc or zinc alloy plating layer (2) electroplated or hot-dipped on the base steel sheet (1) A thin film is coated on the surface of the film, dried at a temperature of 60 to 140 ° C. to form a chromate layer 3 of 20 to 80 mg / m 2, and an epoxy modified colored prima 4 and a colored or transparent polyester system thereon. The top coat 5 is formed. The epoxy-modified colored primer 4 has a dry film thickness (DFT) of 4-10 μm, preferably 5 μm, and the colored or transparent polyester-based top coat 5 has a thickness of 12-30 μm. . If the thickness of the top coat is 12㎛ or less, fine surface wrinkles are formed. If the thickness of the top coat is 30㎛ or more, the surface wrinkles are well formed, but it is disadvantageous in terms of economics. Roll coated steel sheet at PMT (peak metal temperature) 190 ~ 240 ℃ heated to dry. In addition, according to the demands of the application and demand, the embossed roll engraved with the concave-convex pattern may be finally pressed down on the steel sheet to form a three-dimensional pattern on the surface.

As a result of the surface wrinkle and functional test results of the color-coated steel sheet according to the present invention was found to be significantly superior to the conventional compared to the general PCM steel sheet, an example thereof will be presented next.

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

-Coil standard: W (Width) 1040 × T (Thickness) 0.5mm GI (Molten zinc plated steel sheet)

-Dry coating thickness: 5-6 ㎛ under coat, 16-17 ㎛ with coat

-Surface gloss 60 °: Extremely matt (5 to 10%)

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

-Top coat paint viscosity (25 ℃, based on # 4 Ford cup) 70 seconds

-Roll coating method: full reverse

-Hado: 8000 series of Construction Chemical

Table 2 Composition of Top Paint

Topcoat Components Content (parts by weight) Example 1 Example 2 Example 3 Example 4 Example 5 Polyester resin (ES series of SKI company) 40 24 25 40 38 Melamine resin (cymel 300 series from Cytec) 10 6 6 10 10 Organic pigments (carbon black of LG Chem) · 2 · · · Inorganic Pigments (TiO ₂ 902 / chrome yellow)) · 25 (25/0) 30 (25/5) · · Organic filler (VESTOSINT series transparent and black from DEGUSSA-HULS) 3 (transparent + black) 2.5 (transparent) · 2.5 (transparent) 2.5 (transparent) Inorganic filler (GRACE Davison's Syloid series) One One · One One Deforming agent (Japanese public company AC-300) 0.2 0.2 0.2 0.2 0.2 Leveling agent (URALAC 60% URED DD-27) 0.3 0.3 0.3 0.3 0.3 Curing accelerator (50% Nacure series) 3 3 3 3 3 Co-promoters (secondary amine reagents) · · One · One Solvents (hydrocarbons and esters) 42.5 36 34.5 43 44

First, preliminary experiments were performed over four times (steps 1, 2, 3, and 4) as shown in Table 3 below. Here, LINE SPEED was 100mpm, and PMT degree was 200-205 degreeC / PMT phase was 230-235 degreeC. However, in case of undercoat, it only affects basic physical properties such as adhesion and processability, so that the temperature pattern for each zone of the drying oven is fixed the same.

The conditions of the top coat were primarily fixed at 700 RPM in the whole zone wind speed in the process 1, 2 and 3, and the results were observed by changing the temperature pattern for each zone. Afterwards, the temperature pattern for each zone of the oven was fixed based on the process 2 showing the most favorable results among the processes 1 to 3, but the wind speed of only the initial zone (# 1, 2) in the oven was raised to 900 RPM. The results were compared with those of Steps 1-3. Table 3 shows the temperature patterns and wind speeds for each zone of the oven.

Table 3

fair Subsurface temperature [℃] Top Temperature [℃] PMT by oven zone PMT by oven zone Wind speed One 200 ~ 205 ℃ 260/310/310/290 225 ~ 240 ℃ 220/250/280/280/280/270 700 RPM 2 250/260/270/280/280/260 3 280/280/270/270/270/250 4 250/260/270/280/280/260 800 RPM

As a result of preliminary testing under the conditions of the process 1-4 of Table 3, the conditions of the process 1-3 are slightly different in the surface appearance considering the bubble, workability, and roll mark state of the coating film. When the PMT was above 225 ℃ at the fixed wind speed (700RPM), it was found that there was no difference in wrinkle formation according to the temperature change. However, in step 4, the wind speed of only the initial zones (# 1, 2) in the oven was increased to 800 RPM, resulting in a more obvious visual stereoscopic effect, and there was no difference in physical properties. This suggests that the formation of surface wrinkles is more affected by the initial wind speed in the oven than the change in temperature pattern.

The following results were obtained by applying the line speed and temperature pattern of the process 4 showing the best results under the four process conditions.

(Example 1)

Clear (transparent) topologies were mixed by adding clear and colored polyamides. The following pictures are for showing the surface condition of the dry film formed. Picture 1-1 is the actual surface picture and Picture 1-2 is a 160 times magnification.

(Photo 1-1)

(Photo 1-2)

(Example 2)

Transparent polyamide was added to the blackness in order to give the unevenness. Photo 2-1 is the actual surface image and Photo 2-2 is a 160x magnification.

(Photo 2-1)

(Photo 2-2)

(Example 3)

Only surface wrinkles were applied to the colored (beige) tops and treated with wood veneer embossing rolls.

(Photo 3-1)

(Photo 3-2)

(Example 4)

It is a case where only unevenness | corrugation is applied and transparent polyamide is added to a transparent top coat.

(Photo 4-1) (actual surface)

(Photograph 4-2) (160 times)

(Example 5)

This is a case where both unevenness and wrinkles are applied, and transparent polyamide is added to the transparent paint.

(Photo 5-1)

(Photo 5-2)

As a result of testing Example 1 to 5 under the conditions of the process 4 of Table 3, it was found that the surface wrinkles were better formed in the transparent paint without the pigment than the colored paint, and the transparent single polyamide in terms of visual and texture. Rather, it was found that the mixing with the colored polyamide was more diverse than the mixing of the transparent and colored polyamides.

Table 4 shows the results of comparing the physical properties of the general PCM and the coating film of the Example.

Table 4

division General PCM Example 1 Example 2 Example 3 Example 4 1. Workability ○ ○ ○ ○ ○ 2. Roll mark ○ ○ ○ ○ ○ 3. Surface wrinkles and / or irregularities none ○ ○ 0 ○ 4. Solvent resistance 40 times 73 70 70 75 5. Pencil Hardness H 2H 2H H 2H 6. Processability T-bending 2T 1T 1T 1T 1T S-cupping △ ○ ○ ○ ○ 7. Adhesiveness 100/100 100/100 100/100 100/100 100/100 8. IMPACT △ ○ ○ ○ ○ 9. Chemical resistance 5% NaOH ○ ○ ○ ○ ○ 5% HCl ○ ○ ○ ○ ○ 10. Corrosion resistance (1000hr) ○ ○ ○ ○ ○ 11.UV resistance 500hr 0.64 0.21 0.23 0.19 0.20 1000hr 1.50 0.66 0.63 0.68 0.64 12. Weather resistance 500hr 1.45 0.45 0.48 0.45 0.44 1000hr 4.15 1.85 1.86 1.83 1.82

○: good / △: normal / ×: poor

-Workability of 1: Pick up at the time of roll coating

-2 roll marks: the degree of marks in the field roll coating

-Surface wrinkles and / or irregularities of 3: degree of surface wrinkles and / or irregularities of the dry coating film

-Solvent resistance of 4: M.E.K Rubbing

-Pencil hardness of 5: Numerical results of scratch resistance with "Uni Pencil" manufactured by Mitsubishi Corporation of Japan

-Machinability of 6: T-bending, cracking state after square cupping

-Adhesiveness of 7: 6mm cross cut

-8 Impact: 1 / 2Φ × 1kg × 50cm

-Chemical resistance of 9: Color difference between the test specimen and the test specimen soaked in 5% NaOH, 5% HCl solution for 24 hours.

-Corrosion resistance of 10: S.S.T (solt spray test) 35 ℃ 5% Nacl, 1000hr

-U.V resistance of 11: Measured △ E value after measuring 20w × 20cm × 500hr

-Weather resistance of 12: Measure △ E after 300 hours of Xenon arc lamp

According to the comparison results of the above tests, zinc or zinc alloy plated color coated steel sheet according to the present invention is shown to have superior properties in terms of functionality such as surface appearance and weather resistance compared to conventional modified modified colored steel sheet. I could confirm it.

In particular, in addition to the environmentally friendly appearance of new sensibility that can feel the texture and feel similar to natural materials such as stone, wood, and textiles, the weather resistance and UV resistance of the general physical properties are different from those of general modified color steel sheets. The results are shown. Therefore, it can be seen that the application to the steel sheet for interior and exterior materials building materials with designability. In addition, according to the application and the needs of the consumer, the embossing roll with the uneven pattern is rolled on the steel sheet in addition to the antibacterial and antistatic function (Patent registration No. 210287), the addition of the self-cleaning function (Patent Application No. 99-8073). When used in combination with the technique of forming a three-dimensional pattern on the surface by treatment (Patent No. 229208), the functionality and design can be further added.

Claims (6)

The zinc or zinc alloy plating layer (2), the chromate layer (3) and the epoxy-modified or polyester-modified primer undercoat layer (4) are sequentially formed on the base steel sheet (1), A resin comprising a main resin is a polyester resin, a crosslinking agent is a melamine resin, and a curing accelerator, other additives, a solvent, and the like is coated on the undercoat layer 4 to form a top coat layer 5, wherein the top coat layer In order to form the irregularities in the top coat constituting the top coat layer (5) for construction materials, characterized in that it essentially comprises 0.5 to 3 parts by weight of organic or / and 0.5 to 1.0 parts by weight of inorganic fillers relative to the top coat Prepainted Steel Sheet. The component constituting the top coat layer (5) according to claim 1, which promotes curing of the polyester resin and melamine resin and is 0.5 to 3.0 parts by weight of pure amine, preferably secondary, based on the top coat as a wrinkle forming agent. Coloring steel sheet for dry materials, characterized in that further including the amine to create a difference in the curing rate of the inside and outside the coating film during the baking process of the top coat film. The zinc or zinc alloy plating layer (2), the chromate layer (3) and the epoxy-modified or polyester-modified primer undercoat layer (4) are sequentially formed on the base steel sheet (1), A resin comprising a main resin is a polyester resin, a crosslinking agent is a melamine resin, and a curing accelerator, other additives, a solvent, and the like is coated on the undercoat layer 4 to form a top coat layer 5, wherein the top coat layer ( 5) The top coat constituting the top coat, which promotes the crosslinking of the polyester resin and the melamine resin and essentially contains 0.5 to 3.0 parts by weight of a pure amine, preferably a secondary amine, to the top coat as a wrinkle forming agent. Color coating steel sheet for dry materials, characterized in that the wrinkles formed on the surface of the top coat film by making a difference in the curing rate of the inside and outside the coating film during the baking process. The method according to any one of claims 1 to 3, wherein the polyester resin is an oil-free polyester having a number average molecular weight of 10,000-30,000, a glass transition temperature (Tg) of -5 ~ 45 ℃, and an OH value of 40 ~ 90 A color coated steel sheet for building materials, characterized in that it is a modified oil-free polyester compound reacted with a conventional sulfur-free polyisocyanate. Color-coated steel sheet for construction materials according to any one of claims 1 to 3 having a thickness in the following range. Top coat: 12 ~ 30 ㎛ Subcontracting Film: 4 ~ 10 ㎛ Chromate layer: 20 to 80 mg / ㎡ Plating layer: 15 ~ 23 ㎛ Of the color coated steel sheet according to claim 5, wherein the line speed is 60 to 100 mpm, the drying temperature of the chromate layer 3 is 60 to 140 ° C, and the drying temperature of the coating layer is PMT 190 to 240 ° C. Manufacturing method.