KR101403769B1 - Ultraviolet-curable color composition and steel sheet using the same - Google Patents

Abstract

The present invention relates to an ultraviolet ray cured color resin composition comprising 35-70 parts by weight of a principal resin comprising an acrylate oligomer, 5-40 parts by weight of a pigment, and 0.1-5 parts by weight of a flake. The present invention uses an ultra violet curing color resin composition to have an excellent scratch resistance, and manufactures a surface processed steel sheet by a clean process without using a solvent to be an environmentally friendly and have a rapid curing speed.

Description

[0001] The present invention relates to an ultraviolet-curable color resin composition and a steel sheet using the same,

The present invention relates to a UV-curable color resin composition and a steel sheet using the UV-curable color resin composition. The present invention relates to an ultraviolet-curing color resin composition which does not use a solvent and has no problem of solvent volatilization, To a steel sheet used.

In general, steel materials such as steel sheets form a coating film on the surface thereof to provide surface protection, corrosion prevention, and material beauty.

Typical methods for forming a coating film on a steel material such as a steel sheet include a PCM (Precasted Metal) method in which a resin composition such as a paint is coated on the surface of a steel material, and a method in which a film sheet, And a laminating method.

However, in the above-mentioned prior art, a resin composition for forming a coating film, that is, a coating paint is composed of a polyester or a polyurethane type and is coated on a steel material such as a steel plate by a thermal curing method to form a coating film, High temperature drying equipment for evaporation is required.

Therefore, the time required for the coating operation is increased and the productivity is decreased.

In particular, since the conventional solvent volatilization type coating method, thermal curing type coating method, electrostatic and electrodeposition coating method, and powder coating method for forming a coating film on a metallic material such as a steel product all require a heating process, There is a problem that energy consumption is increased.

Moreover, since the conventional oil-based resin composition, that is, the paint, contains substances that cause air pollution and global warming, there is a need to improve the environmentally friendly method.

In order to overcome the above-mentioned problems, a method of using an ultraviolet ray hardening resin composition that is environmentally friendly and capable of mass production has been developed. In Korea, development of ultraviolet ray curing coatings, especially ultraviolet ray hardening resin compositions, that is, paints, has been developed in the early 1980s, and its application fields have been variously developed and used for wood and plastic materials.

However, when the color is expressed using such an ultraviolet ray hardening resin composition, the pigment contained in the ultraviolet ray hardening resin composition interferes with the ultraviolet ray penetration, so that the hardening is not performed well or the hardness of the coat is lowered.

FIG. 1 of the present invention shows a curing process of a conventional UV-curable color resin composition, in which ultraviolet rays are not completely transmitted by a pigment, and only a part of ultraviolet rays penetrate through a coating film. That is, when an ultraviolet ray hardening resin composition containing a pigment is used, it is impossible to manufacture a surface treated steel sheet.

The present invention provides a color resin composition which provides scratch resistance, corrosion resistance and adhesion as an ultraviolet curing color resin composition for forming a coating film of a steel material such as a metal material and a steel sheet in particular.

In addition, the present invention provides a surface-treated steel sheet in which a coating film coated with an ultraviolet-curing color resin composition is formed on a top surface of a steel material such as a metal material, specifically, a steel sheet.

The present invention relates to a resin composition comprising 35 to 70 parts by weight of a main resin comprising an acrylate oligomer; 5 to 40 parts by weight of a pigment; And 0.1 to 5 parts by weight of a flake.

Further, the present invention relates to a surface-treated steel sheet on which a coating film is formed by applying the aforementioned ultraviolet-curing color resin composition.

The present invention uses a UV curable color resin composition to provide a steel sheet having excellent scratch resistance and a surface-treated steel sheet in a clean process that does not use a solvent, thereby being environmentally friendly and having a short curing speed .

Further, since the ultraviolet curable color coating layer and the ultraviolet curable coating layer use the same type of main resin, adhesion between coating layers is excellent.

1 shows a curing process of an ultraviolet curable color resin composition using a conventional ultraviolet curing system.
2 shows a curing process of the ultraviolet curable color resin composition using the ultraviolet curing system according to the present invention.
Fig. 3 shows the effect of improving the corrosion resistance of the ultraviolet curing color coating layer according to the present invention.
Fig. 4 shows an example of a surface-treated steel sheet according to the present invention.

The present invention relates to a resin composition comprising 35 to 70 parts by weight of a main resin comprising an acrylate oligomer;

5 to 40 parts by weight of a pigment; And

And 0.1 to 5 parts by weight of a flake.

In the present invention, "part by weight" represents the weight ratio between the individual components and the composition.

Hereinafter, the ultraviolet-curable color resin composition according to the present invention will be described in more detail.

The main resin included in the ultraviolet curable color resin composition of the present invention includes an acrylate oligomer.

The type of the acrylate oligomer is not particularly limited, and it may be a modified epoxy acrylate oligomer, a urethane acrylate oligomer, a polyester acrylate oligomer, a fluorinated acrylate oligomer, a polybutadiene acrylate, a silicone acrylate and an alkyl acrylate , And specifically, a mixture of a modified epoxy acrylate oligomer and a urethane acrylate oligomer may be used.

In the present invention, by using a modified epoxy acrylate oligomer and a urethane acrylate oligomer together with the acrylate oligomer, corrosion resistance, impact resistance, scratch resistance and adhesion can be secured.

The modified epoxy acrylate oligomer may provide bending property (workability) and adhesion property when the UV curable color resin composition is formed as a coating film. The modified epoxy acrylate oligomer is not particularly limited and may be an urethane-modified epoxy acrylate oligomer. Specific examples thereof include Miramer ME 1201 manufactured by MI Won Co., Ltd., CN 150 / 80, EA 1580 of HS Chemtron, and 3020-A80 of AGI Co. may be used.

The content of the modified epoxy acrylate oligomer is not particularly limited and may be 25 to 45 parts by weight, specifically 30 to 38 parts by weight based on 100 parts by weight of the ultraviolet curable color resin composition. If the content is less than 25 parts by weight, corrosion resistance and scratch resistance may be deteriorated. If the content is more than 45 parts by weight, the viscosity of the composition may increase and the workability may decrease.

The urethane acrylate oligomer may be used together with a modified epoxy acrylate oligomer to provide a bendability (workability) and an adhesion property when the UV curable color resin composition is formed into a coating film. The kind of the urethane acrylate is not particularly limited and may include a bifunctional urethane acrylate oligomer.

Since the bifunctional urethane acrylate has two functional groups, flexibility can be maintained by reducing cross-linking during ultraviolet polymerization. The bifunctional urethane acrylate may use a reaction product of an alicyclic diisocyanate and a (meth) acrylate containing a hydroxy group, wherein the alicyclic diisocyanate is a compound selected from the group consisting of isophorone diisocyanate and dicyclohexane diisocyanate It may be more than one selected. The bifunctional urethane acrylate may be a bifunctional urethane acrylate containing an alicyclic diisocyanate prepolymer, which may be a diisocyanate of an alicyclic structure, such as isophorone diisocyanate (IPDI), dicyclohexane diisocyanate W) and the like and a hydroxyl group-containing acrylic acid ester.

In the present invention, the urethane acrylate oligomer is selected from UEC-2205 UA-2205 UA-2890BX, UA-5221 of HS Chemtron, CN 966J75, CN 966H90 of Sartomer, Ebecryl 244 and Ebecryl 284 of Cytec Or a mixture of two or more thereof.

The content of the urethane acrylate oligomer is not particularly limited and may be 10 to 25 parts by weight, specifically 15 to 20 parts by weight, based on 100 parts by weight of the color resin composition. If the content is less than 10 parts by weight, the hardness of the coating film may increase and the bending workability (workability) and the bending workability and adhesiveness may decrease in particular. When the content is more than 25 parts by weight, There is a possibility of decrease.

In the present invention, the above-mentioned main resin may be used in an amount of 35 to 70 parts by weight.

The ultraviolet curable color resin composition of the present invention may further include a reactive acrylic monomer in order to compensate the workability and the like of the main resin.

The type of the reactive acrylic monomer is not particularly limited and may include at least one selected from the group consisting of a monofunctional acrylic monomer and a bifunctional acrylic monomer. Specifically, the monofunctional and bifunctional acrylic monomers are mixed It is good to use.

Examples of the monofunctional acrylic monomer include acryloylmorpholine (ACMO), tetrahydrofurfuryl acrylate (THFA), hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), and isobornyl acrylate (IBOA) And the like can be used.

The content of the monofunctional acrylic monomer is not particularly limited and may be 25 to 35 parts by weight based on 100 parts by weight of the ultraviolet curable color resin composition. If the content is less than 25 parts by weight, the viscosity may increase and the adhesion may be deteriorated. If the content is more than 35 parts by weight, the ultraviolet curing property may decrease and the productivity may be decreased.

The bifunctional reactive acrylic monomer is mainly used as a viscosity modifier, and examples thereof include diethylene glycol diacrylate (DEGDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), hexanediol A monomer selected from diacrylate (HDDA), polyethylene glycol 400 diacrylate (PEG 400DA) and polyethylene glycol 600 diacrylate (PEG 600DA) may be used.

The content of the bifunctional reactive acrylic monomer is not particularly limited and may be 7 to 15 parts by weight based on 100 parts by weight of the ultraviolet curable color resin composition. If the content is less than 7 parts by weight, the viscosity may increase. If the content is more than 15 parts by weight, the overall coating film properties may be adversely affected.

In the present invention, the content of the reactive acrylic monomer is not particularly limited and may be 32 to 48 parts by weight based on 100 parts by weight of the ultraviolet curable color resin composition. If the content is less than 32 parts by weight, the viscosity may increase and the adhesion may be deteriorated. If the content is more than 48 parts by weight, the ultraviolet curing property may decrease and the productivity may be decreased.

Further, the ultraviolet-curing color resin composition of the present invention may further comprise a photoinitiator and an additive.

In the present invention, the photoinitiator can easily cause the polymerization reaction of the resin composition when ultraviolet light is irradiated after applying the ultraviolet curable color resin composition to the surface of a metal material such as a steel sheet to form a coating film. The type of the photoinitiator is not particularly limited, and conventional polymerization initiators which are activated by ultraviolet rays can be used. Specific examples thereof include benzophenone, benzoin, benzoin ether, benzylketal, , Anthraquinone-based compounds, thioxanthone-based compounds, and the like. Examples of commercial products commercially available as the above photoinitiator include Irgacure 184, 754, 819, Darocur 1173, TPO, Micure CP-4, MP-8, BP and TPO manufactured by Ciba Geigy, In consideration of easiness in the manufacturing process, Irgacure 754, Darocur 1173, Micure MP < (R) >, which is a liquid initiator, -8 is recommended.

The content of the photoinitiator is not particularly limited and may be 5 to 10 parts by weight based on 100 parts by weight of the ultraviolet curable color resin composition. Ultraviolet curing is easily performed in the above content range.

The additive in the present invention is not particularly limited as long as it is an additive commonly used in the art, and is preferably used as a defoaming agent for removing air bubbles generated during a roll coating operation, a leveling agent for influencing the film surface appearance and surface scratch resistance, and / An adhesion promoting agent may be used.

TEGO Glide 410, 440, TEGO Rad 2250, BYK-UV 3500, 3510 and the like can be selected as the leveling agent, and the leveling agent can be selected from the group consisting of TEGO Airex 920, 932, BYK 088 and 1790. As the adhesion promoter, an acrylic phosphate-based adhesion promoter such as hydroxyethyl acryloyl phosphate, hydroxyethyl methacrylate phosphate and the like can be selected and used.

The content of the antifoaming agent, leveling agent and adhesion promoting agent is not particularly limited, and 0.4 to 0.6 parts by weight of a defoaming agent, 0.4 to 0.6 parts by weight of a leveling agent and 0.5 to 1.5 parts by weight of an adhesion promoter are added to 100 parts by weight of the entire ultraviolet- . If the content of the adhesion promoter is less than 0.5 parts by weight, the interlayer adhesion may be lowered. If the amount is more than 1.5 parts by weight, the viscosity of the composition may increase, which may affect the workability.

The content of the additive of the present invention is not particularly limited and may be 1.3 to 2.7 parts by weight based on 100 parts by weight of the entire ultraviolet curable color resin composition. The effect is excellent in the above range.

The pigments contained in the ultraviolet curable color resin composition of the present invention are used to realize the color of the coating film to be produced. The kind of the pigment is not particularly limited and may be selected from the group consisting of titanium dioxide (TiO ₂ ), mercury sulphide (HgS), copper carbonate (CuCO ₃ ), copper hydroxide (Cu (OH) ₂ ), arsenic disulfide (As ₂ S ₂ ) (Pb ₃ O ₄ ), lead carbonate (PbCO ₃ ), calcium carbonate (CaCO ₃ ), diazo yellow, carbon black, zinc oxide, copper sulfate, phthalocyanine blue, clay, Red soil, loess soil and loess soil, and the like.

The average particle diameter of the pigment is not particularly limited and may be 5 占 퐉 or less, specifically 1 占 퐉 or less, more specifically 200 nm or less. When the pigment size is 200 nm or less, ultraviolet rays are transmitted without using reflective flakes, and a coating film having excellent physical properties can be produced. When the thickness is more than 200 nm, the coating film can be easily cured by increasing the reflectance of ultraviolet rays by using flakes together, and when a pigment and flakes of less than 200 nm are used together, a coating film having superior physical properties can be manufactured . If the particle diameter of the pigment exceeds 5 탆, the particle size is large, which may interfere with ultraviolet curing or may hinder the smoothness of the surface of the coating film.

The content of the pigment is not particularly limited and may be 5 to 40 parts by weight based on 100 parts by weight of the ultraviolet curable color resin composition. Ultraviolet ray hardening can be easily performed in the above content range, and a beautiful color can be imparted to the surface treated steel sheet to be produced.

The flake contained in the ultraviolet curable color resin composition of the present invention diffuses ultraviolet rays when curing ultraviolet rays to diffuse ultraviolet rays to every corner of the pigment to easily perform ultraviolet curing. Thus, in the present invention, a hard ultraviolet cured coating film can be produced.

The flake may have a transmittance of less than 50% and a refractive index of 3 or more in an ultraviolet region of 200 to 400 nm.

As shown in Table 1 below, a material having a refractive index of 3 or more can be used as a flake, since the reflectance is generally 30% when the refractive index is 3.5 and the film hardening degree is excellent.

Refractive index reflectivity(%) Coating hardness (%) 2 11 Bad 3.5 30 usually 10 67 Good 20 81 Good

The flakes may have a length and a thickness of 100 to 3000 nm, respectively. When the thickness is less than 100 nm, the reflective flake has a difficulty in its role and the reflection efficiency may deteriorate. When the thickness exceeds 3000 nm, the leveling property of the coating film surface may be deteriorated. That is, the reflection efficiency and leveling property are excellent in the above limited range.

The specific kind of the flake is not limited and may be selected from the group consisting of titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), indium tin oxide (ITO), zinc sulfide (ZnS) ZnSe), silicon (Si), and the like.

The indium tin oxide (ITO) is 400 to 800 nm, the zinc sulfide (ZnS) is 400 to 14000 nm, and the tin oxide (Ta2O5) is 400 to 7000 nm. , Zinc selenide (ZnSe) at 600 to 15000 nm, and silicon (Si) at a wavelength of 1000 to 9000 nm, the flakes have a transmittance of less than 50% at a wavelength of 200 to 400 nm, Can be used.

The content of the flake is not particularly limited and may be 0.1 to 5 parts by weight based on 100 parts by weight of the ultraviolet curable color resin composition. If the content of the flake is less than 0.1 part by weight, the curing efficiency due to diffuse reflection may be lowered. If the content of the flake exceeds 5 parts by weight, ultraviolet ray blocking effect may occur rather than diffused reflection effect, There is a possibility that the workability of the coating film becomes weak.

The ultraviolet-curable color resin composition of the present invention may contain various additives, for example, antioxidants, light stabilizers, ultraviolet absorbers, heat-hardeners, lubricants, defoamers, dispersants, antistatic agents, plasticizers, An organic filler, or a mixture thereof. At this time, the content of the additive may be selected within a range that does not change the physical properties required by the ultraviolet curable color resin composition of the present invention, for example, in a range of 0.1 to 15 parts by weight based on the total ultraviolet curable color resin composition, Can be changed accordingly.

Further, the present invention provides a steel plate comprising: a steel plate; And

And a UV-cured color coating layer formed on one or both surfaces of the steel sheet and formed by the ultraviolet-curing color resin composition described above.

As shown in FIG. 4, the surface-treated steel sheet includes a steel sheet;

A pretreatment layer formed on one side or both sides of the steel sheet;

An ultraviolet curing color coating layer formed on the pretreatment layer and formed by the ultraviolet curing color resin composition; And

And an ultraviolet curing coating layer formed on the ultraviolet curing color coating layer.

The kind of the steel sheet is not particularly limited, and it may be a cold rolled steel sheet; galvanized steel; Galvanized electroplated steel sheet; Hot - dip galvanized steel; Aluminum-plated steel sheet; A coated steel sheet containing an impurity or a dissimilar metal such as cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, iron magnesium, tin, copper or a mixture thereof; Aluminum alloy plate to which silicon, copper magnesium, iron, manganese, titanium, zinc or a mixture thereof is added; Galvanized steel plates coated with phosphate; Cold rolled steel sheets; And a hot-rolled steel sheet. In addition, the thickness of the steel sheet is not particularly limited, and its thickness can be adjusted according to the intended use.

In the surface treated steel sheet of the present invention, the ultraviolet ray color coating layer can be formed by coating the above-described ultraviolet ray-cured color resin composition on one side or both sides of a steel sheet, followed by ultraviolet ray curing. At this time, the ultraviolet ray curing can be used without limitation in the curing method generally used in the art.

Specifically, the ultraviolet ray for curing the ultraviolet curable color resin composition preferably has a wavelength of 400 nm. At this time, as a light source for irradiating ultraviolet rays, a metal halide such as a medium pressure mercury lamp, a high pressure mercury lamp, a H bulb without electrode, a D bulb, and a V bulb (fusion, USA) have. The amount of ultraviolet ray irradiation may be 0.1 to 10 J / cm < ² >.

In the present invention, as shown in FIG. 2, since the ultraviolet curable color coating layer includes flakes, the flakes irregularly reflect ultraviolet rays to diffuse to every corner of the pigment, so that a hard coat layer can be formed even in the presence of pigment. Particularly, when the particle size of the pigment is 200 nm or less, the effect of diffusing reflection is increased and a harder coat layer can be formed. 2 (a) shows a case where the pigment has a particle diameter of 1 to 5 탆, and Fig. 2 (b) shows a case where the particle diameter is 200 nm or less.

Also, as shown in FIG. 3, since the color coating layer according to the present invention includes flakes, it is possible to lengthen the transmission dew of oxygen and moisture, thereby prolonging the time for generating rust. That is, the flake has a barrier effect and can prevent corrosion of the material.

In the present invention, the thickness of the ultraviolet color coating layer is not particularly limited and may be 10 to 30 탆. The expression of a desired color in the above-mentioned thickness range is excellent, and workability and corrosion resistance can be ensured.

Further, in the surface treated steel sheet of the present invention, the pretreatment layer may be formed between the steel sheet and the ultraviolet curable color coating layer. The pretreatment layer can improve adhesion between the steel sheet and the UV curable color coating layer. Particularly, in the present invention, the pretreatment layer is uncured to have a little sticky property, and then the ultraviolet curing color coating layer is cured at a high temperature to improve adhesion between the coating layer and the pretreatment layer . In addition, in the present invention, it is possible to improve the coating film adhesion by forming a pretreatment layer on a steel sheet, corona treatment at room temperature, and then forming an ultraviolet curing color coating layer.

The resin composition for forming the pretreatment layer may be a conventional pretreatment resin composition used in the art. In the present invention, specifically, a Cr layer Cr-free resin composition may be used as the pretreatment layer.

The pretreated resin composition may be coated on the steel sheet at a thickness of 10 to 400 mg / m ² , and then dried at a temperature of 30 to 120 ° C., followed by cooling. At this time, if the thickness is less than 10 mg / m ² , it may be difficult to secure the function of the pretreatment coating film. If it exceeds 400 mg / m ² , the coating film may peel off due to breakage of the coating film.

Further, the surface-treated steel sheet of the present invention can form an ultraviolet curing coating layer on the ultraviolet curing color coating layer. The ultraviolet-cured coating layer can impart a surface appearance to the surface-treated steel sheet such as excellent processability and high gloss.

The type of the resin forming the ultraviolet curable coating layer is not particularly limited as long as an ultraviolet curable resin is used, and may include the same main resin as the ultraviolet curable color resin composition described above. In the present invention, the ultraviolet curable color coating layer and the ultraviolet curable coating layer include the same type of main resin, so that the adhesion is excellent.

The thickness of the ultraviolet curing coating layer is not particularly limited and may be 0.5 to 15 탆. It is possible to give an excellent surface appearance in the above range.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: FIG. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and is defined only by the scope of the claims of the invention.

Example

A pretreatment coating solution (a solution according to an embodiment of Korean Patent No. 0679659) was coated on the zinc-plated steel sheet at a thickness of 10 to 100 mg / m ² , then dried at 30 to 120 ° C and then cooled in air to form a pretreatment coating layer .

Thereafter, 47 parts by weight of a urethane acrylate oligomer (UA-5221, HS Chemtron, Korea), tetrahydroperfuryl acrylate (THFA) [SR285, Sartomer, USA] and hexanediol diacrylate (HDDA) 10 parts by weight of TiO ₂ pigment having an average particle diameter of 5 μm or less, 30 parts by weight of a photoinitiator [Darocur 1173, Ciba Chemicals, Switzerland], a leveling agent [TEGO Rad2250, Evonik, Germany] 0.5 And 0.1 to 5 parts by weight of a flake is coated on a pretreatment coating layer and then an ultraviolet ray is irradiated and cured to form an ultraviolet cured color coating layer having a thickness of 7 to 12 탆 to form a surface treated steel sheet .

Comparative Example

A surface-treated steel sheet was prepared in the same manner as in Example 1, except that the flakes were not used.

The physical properties of the surface-treated steel sheets prepared in Examples and Comparative Examples were measured and reported in Table 2 below.

Experimental Example

1. Measurement of film hardening degree

The surface treated steel sheets prepared in Examples and Comparative Examples were rubbed with gauze embedded with MEK by reciprocating with a constant force, and then the state of the coating film was observed.

⊚: more than 50 times, ∘: less than 20 times, Δ: less than 10 times, ×: less than 5 times

2. Pencil hardness measurement

The pencil hardness was measured according to JIS K5600-5-4KS.

For reference, the pencil hardness is measured at 9B to 9H, the hardness becomes weaker toward 9B, and the harder the hardness becomes toward 9H.

3. Adhesion measurement

100 surface-treated steel sheets prepared in Examples and Comparative Examples were cut out with a cutter so as to have a size of 1 mm in width X lengthwise, and 3M tape was attached and then peeled off to evaluate the adhesion of the coated film.

Example Comparative Example Coating hardness (MEK Rubbing) ◎ X Pencil hardness F or more Can not be tested Adhesiveness No peeling Can not be tested

As shown in Table 2, it can be confirmed that the ultraviolet-curable color coating layer is excellent in the degree of curing of the coating film, pencil hardness and adhesiveness in Examples including the pigment and the flakes.

Claims (16)

35 to 70 parts by weight of a main resin comprising an acrylate oligomer;
5 to 40 parts by weight of a pigment; And
0.1 to 5 parts by weight of a flake having a length of 100 to 3000 nm and a thickness of 100 to 3000 nm.
The method according to claim 1,
32 to 48 parts by weight of a reactive acrylic monomer;
5 to 10 parts by weight of a photoinitiator; And
And 1.3 to 2.7 parts by weight of an additive.
The method according to claim 1,
The acrylate oligomer comprises at least one selected from the group consisting of modified epoxy acrylate oligomers, urethane acrylate oligomers, polyester acrylate oligomers, fluorinated acrylate oligomers, polybutadiene acrylates, silicone acrylates and alkyl acrylates. UV curable color resin composition.
The method of claim 3,
Wherein the modified epoxy acrylate oligomer is an epoxy acrylate oligomer modified with an urethane-based ultraviolet curable color resin composition.
3. The method of claim 2,
Wherein the reactive acrylic monomer comprises at least one member selected from the group consisting of a monofunctional acrylic monomer and a bifunctional reactive acrylic monomer.
3. The method of claim 2,
The photoinitiator comprises at least one selected from the group consisting of benzophenone, benzoin, benzoin ether, benzyl ketal, acetophenone, anthraquinone, and thioxanzone.
3. The method of claim 2,
Wherein the additive comprises at least one selected from the group consisting of a defoaming agent, a leveling agent, and an adhesion promoter.
The method according to claim 1,
Wherein the pigment has an average particle diameter of 5 占 퐉 or less.
The method according to claim 1,
The pigments include titanium dioxide (TiO ₂ ), mercury sulphide (HgS), copper carbonate (CuCO ₃ ), copper hydroxide (Cu (OH) ₂ ), arsenic disulfide (As ₂ S ₂ ), lead oxide (Pb ₃ O ₄ ) Selected from the group consisting of lead carbonate (PbCO ₃ ), calcium carbonate (CaCO ₃ ), diazo yellow, carbon black, zinc oxide, copper sulfate, phthalocyanine blue, clay, And at least one ultraviolet-curable colorant resin composition.
The method according to claim 1,
Wherein the flake has a transmittance of less than 50% and a refractive index of not less than 3 in an ultraviolet ray region of 200 to 400 nm.
delete The method according to claim 1,
The flakes are formed of a group consisting of titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), indium tin oxide (ITO), zinc sulfide (ZnS), zinc selenide (ZnSe) Wherein the ultraviolet curing colorant resin composition comprises at least one selected from the group consisting of polyvinyl alcohol,
Steel plate; And
35 to 70 parts by weight of a main resin comprising acrylate oligomer, 5 to 40 parts by weight of pigment, and 100 to 3000 nm of a flake having a thickness of 100 to 3000 nm and formed on one or both sides of the steel sheet, And 5 parts by weight of an ultraviolet curable color resin composition.
14. The method of claim 13,
Steel plate;
A pretreatment layer formed on one side or both sides of the steel sheet;
An ultraviolet curing color coating layer formed on the pretreatment layer; And
And an ultraviolet curing coating layer formed on the ultraviolet curing color coating layer.
14. The method of claim 13,
Cold rolled steel sheets; galvanized steel; Galvanized electroplated steel sheet; Hot - dip galvanized steel; Aluminum-plated steel sheet; A coated steel sheet containing an impurity or a dissimilar metal such as cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, iron magnesium, tin, copper or a mixture thereof; Aluminum alloy plate to which silicon, copper magnesium, iron, manganese, titanium, zinc or a mixture thereof is added; Galvanized steel plates coated with phosphate; Cold rolled steel sheets; And a hot-rolled steel sheet.
14. The method of claim 13,
Wherein the ultraviolet curing color coating layer has a thickness of 10 to 30 占 퐉.

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