KR20180113048A - Coating kit, muti-layered protective film using the same - Google Patents

Abstract

The present invention provides a paint kit for forming a multilayer protective film comprising at least one acrylic polyol resin and a polyester resin, and a multilayer protective film using the same. The multilayer protective film exhibits excellent appearance and coating workability and can enhance physical properties such as adhesion, water resistance, chipping resistance and weather resistance.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating material for a coating material,

The present invention relates to a coating composition for forming a multilayer protective film and a multilayer protective film using the same.

Generally, a method of black coating a vehicle grill is to coat chrome on the entire automobile grille made of ABS (Acrylonitrile Butadiene Styrene Copolymer) resin, sequentially paint a primer and a black paint on other parts of the plated chromium, A process of drying and forming a chromium plating on only a part of a car grill has been used.

However, environmental problems such as wastewater disposal after chrome plating process are emerging in plastic materials, and development of an alternative process of chromium plating is required to solve this problem.

In order to solve the above problem, a hot stamping process has been developed, which is a method in which an aluminum foil is placed on a plastic material, and the aluminum is attached to the material by pressing the plate.

However, since corrosion can be caused only by the hot stamping portion itself, it is necessary to develop a paint and a protective film for protecting the metal substrate such as the protection of the aluminum portion of the hot stamping portion.

Korean Patent Publication No. 2015-0004093

A first technical object of the present invention is to provide a coating composition kit for forming a multilayer protective film.

A second technical object of the present invention is to provide a multilayer protective film comprising the above paint kit.

In one embodiment, the present invention relates to a coating composition comprising 20% to 50% by weight of a first acrylic polyol resin, 20% to 50% by weight of a second acrylic polyol resin and 10% to 30% % By weight of a first coating composition; And a second coating composition comprising 20 wt% to 50 wt% of a third acrylic polyol resin, 20 wt% to 60 wt% of a polyester polyol resin, and 10 wt% to 40 wt% of a second solvent, There is provided a coating composition for forming a multilayer protective film comprising a coating composition.

According to an embodiment of the present invention, there is provided a multilayer protective film painted on a metal substrate, the multilayer protective film sequentially including a first paint layer and a second paint layer on the first paint layer, Wherein the first coating composition comprises 20 to 50% by weight of the first acrylic polyol resin, 20 to 50% by weight of the second acrylic polyol resin and 10 to 30% by weight of the first solvent, based on the total weight of the composition, Wherein the second coating layer comprises 20% by weight to 50% by weight of the third acrylic polyol resin, 20% by weight to 60% by weight of the polyester polyol resin and 10% by weight of the second solvent, based on the total weight of the second coating composition, To 40% by weight of the second coating composition is painted.

The coating composition for forming a multilayer protective film according to an embodiment of the present invention may include a first coating composition and a second coating composition having a specific combination of components, thereby forming a multilayer protective film capable of protecting the metal substrate, The multilayer protective film thus formed exhibits excellent appearance and coating workability, and can improve physical properties such as adhesion, water resistance, chipping resistance and weather resistance.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The coating composition for forming a multilayer protective film according to an embodiment of the present invention may comprise 20 to 50% by weight of the first acrylic polyol resin, 20 to 50% by weight of the second acrylic polyol resin, A first coating composition comprising 10% to 30% by weight of a first solvent; And a second coating composition comprising 20 wt% to 50 wt% of a third acrylic polyol resin, 20 wt% to 60 wt% of a polyester polyol resin, and 10 wt% to 40 wt% of a second solvent, And a coating composition.

The coating composition for forming a multi-layer protective film according to an embodiment of the present invention comprises a first coating composition comprising 20% by weight to 50% by weight of a first acrylic polyol resin and 20% by weight to 50% by weight of a second acrylic polyol resin 20% by weight to 50% by weight of the third acrylic polyol resin, 20% by weight of the polyester polyol resin, and 3% by weight of the second acrylic polyol resin. By weight to 60% by weight, the appearance and durability of the coating film can be improved.

Hereinafter, the present invention will be described in more detail.

The coating kit according to an embodiment of the present invention is a coating composition kit for forming a multi-layer protective film for solving the problem of corrosion of a metal substrate. The coating composition kit includes a first coating composition for securing adhesion and physical properties with a metal substrate, And a second coating composition for ensuring durability.

<First Coating Composition>

The first coating composition contained in the coating composition kit for forming a multilayer protective film according to an embodiment of the present invention comprises a metal substrate, specifically, a paint capable of forming a first coating layer on the aluminum substrate surface of the hot stamping portion and on the plastic, As a composition, adhesion with the above-described substrates and physical properties of the coating film can be further improved. Here, the hot stamping portion may be a material in which aluminum is adhered to a plastic material by placing a metal, for example, an aluminum thin plate on a plastic material, and then pressing it.

According to one embodiment of the present invention, the first coating composition is a two-pack coating composition comprising first and second acrylic polyol resins and a curing agent, and more particularly, to a two- The adhesion to the substrate, the workability and the physical properties of the coating film can be satisfied at the same time through the combination of the polyol resin and the second acrylic polyol resin which can contribute to the appearance of the coating film and the physical properties of the coating film.

Wherein the first coating composition comprises 20 wt% to 50 wt% of the first acrylic polyol resin, 20 wt% to 50 wt% of the second acrylic polyol resin, and 10 wt% to 30 wt% of the first solvent based on the total weight of the first coating composition, . &Lt; / RTI &gt;

The first acrylic polyol resin may have a solid content of 55 wt% to 65 wt%, a hydroxyl group of 60 to 75 mgKOH / g, and a weight average molecular weight (Mw) of 10,000 to 15,000 g / mol.

According to an embodiment of the present invention, the use amount of the first acrylic polyol resin may be very important for realizing the adhesion to an excellent substrate and the physical properties of the coating film. For example, Based on the total weight of the composition, in an amount of 20% by weight to 50% by weight, specifically 25% by weight to 45% by weight. If the content of the first acrylic polyol resin is less than 20% by weight, the adhesion to the substrate tends to be lowered, the smoothness of the coating film may be poor, and the water resistance and weather resistance may be lowered. If the content of the acrylic polyol resin is more than 50% by weight, spraying workability may be adversely affected, the drying property may be poor, and the curing density of the coating film may be lowered, resulting in poor water resistance, weather resistance, and impact resistance.

The second acrylic polyol resin has a solid content of 45 to 55% by weight, a hydroxyl group of 50 to 100 mgKOH / g, a glass transition temperature (Tg) of 20 to 60 ° C, a weight average molecular weight Mw) of from 15,000 to 20,000 g / mol.

According to an embodiment of the present invention, the amount of the second acrylic polyol resin may be important in order to realize both excellent appearance and physical properties of the coating film. For example, the second acrylic polyol resin may have a weight- In an amount of 20% by weight to 50% by weight, specifically 25% by weight to 45% by weight. If the content of the second acrylic polyol resin is less than 20% by weight, the appearance of the coating film may be deteriorated, and the water resistance and weather resistance may be lowered. If the content of the second acrylic polyol resin exceeds 50% by weight, the hardness of the coating film may decrease.

The weight ratio of the first acrylic polyol resin to the second acrylic polyol resin may be 1: 1 to 1: 2, specifically 1: 1.5. When the weight ratio is in the above range, not only paint workability but also physical properties such as adhesion to substrate, water resistance and weather resistance can be improved at the same time. If the weight ratio is out of the range, the adhesion to the substrate and the physical properties of the coating film can be lowered.

According to one embodiment of the present invention, the monomers used in the first and second acrylic polyol resins are specifically 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, 2-hydroxybutyl (Meth) acrylate, and 1,6-hexanediol di (meth) acrylate, and mixtures thereof. The acrylic monomer having at least one hydroxyl group may be copolymerized with a monomer such as styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, .

Meanwhile, the first solvent included in the first coating composition according to one embodiment of the present invention is used to maintain the thickness of the coating film and to improve the workability of the coating. Examples of the first solvent include n-heptane, toluene, xylene, Non-polar solvents such as n-hexane; Ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, dibasic ester, 3-methoxybutyl acetate, amyl acetate, butyl glycol acetate, methyl ethyl ketone, methyl isobutyl ketone, Polar solvents such as butyl ketone, isophorone and cyclohexanone; And a mixture of the nonpolar solvent and the polar solvent may be appropriately selected depending on the characteristics of the resin and the rate of volatilization.

The first solvent may include an ester solvent, an ether solvent, or a mixed solvent thereof. There is no particular limitation on the amount of the solvent to be used. However, if the solvent is used in an excessively large amount, the adhesion may be reduced or the durability may be deteriorated. According to one embodiment of the present invention, the first solvent may be contained in an amount of, for example, 10% by weight to 30% by weight based on the total weight of the first coating composition. More specifically, it may contain 10 wt% to 20 wt% of an ester solvent and 1 wt% to 10 wt% of an ether solvent.

Meanwhile, the first coating composition according to one embodiment of the present invention may further include a curing accelerator for accelerating the reaction between the first and second acrylic polyol resins and the curing agent to shorten the drying time and the curing time of the coating film. As the curing accelerator, for example, tetramethylbutane diamine, bicyclooctane, dibutyltin dilaurate, triethylenediamine and mixtures thereof may be used. The amount of the curing accelerator to be used is not particularly limited, but may be, for example, 0.01 to 1.0% by weight based on the total weight of the first coating composition. When the amount of the curing accelerator used is less than 0.01% by weight, drying properties and physical properties of the coating film may be deteriorated. If it exceeds 1.0% by weight, appearance degradation and pot life may be shortened.

In addition, the first coating composition according to an embodiment of the present invention may further include a surface conditioner for adjusting the surface tension of the coating material. As the surface modifier, additives commonly used in the coating composition may be used for controlling the surface tension. For example, a polyacrylate surface modifier and / or a silicone surface modifier may be used. The amount of the surface modifier to be used is not particularly limited, but may be, for example, 0.1 to 1.0% by weight based on the total weight of the first coating composition. If the amount of the surface modifier is less than 0.1% by weight, the appearance may be deteriorated. If the amount is more than 1.0% by weight, the re-coat adherence may be deteriorated.

In addition, the first coating composition according to an embodiment of the present invention may further include an ultraviolet absorber. The ultraviolet absorber has a stronger UV absorbing ability than a chromophore of an acrylic resin, thereby suppressing the generation of radicals of the acrylic resin, and is effective in preventing discoloration, swelling, delamination, and gloss loss of the acrylic resin. For example, hydroxyphenylbenzotriazole may be contained in an amount of 1 to 10% by weight. If the content of the ultraviolet absorber is more than 10% by weight, a problem of cost increase may occur. If the content of the ultraviolet absorber is less than 1% by weight, a problem of degradation of weatherability may occur.

More specifically, according to one embodiment of the present invention, the first coating composition comprises 25 wt% to 45 wt% of the first acrylic polyol resin, 25 wt% to 45 wt% of the second acrylic polyol resin, 1 to 10% by weight of an ultraviolet absorber, 0.01 to 10% by weight of a curing accelerator, 1 to 10% by weight of an ester solvent, 1 to 10% To 1% by weight. When the above range is satisfied, the adhesion to the metal substrate and the physical properties of the coating film can be optimally improved.

On the other hand, the first coating composition may be a polyisocyanate as a curing agent for curing the resin.

Specifically, at least one of methylene diisocyanate, toluene diisocyanate or xylene diisocyanate homopolymer or modified product which is excellent in curing rate, adhesion property, film hardness and heat resistance and low in cost can be selected and used. When polyisocyanate is used, it is excellent in adhesiveness, moisture resistance, coating film hardness, and the like to various plastic molded articles, and its price is relatively low, which is advantageous in terms of economy.

In the present invention, the reaction ratio (NCO / OH) of the isocyanate of the polyisocyanate curing agent to the hydroxyl group in the acrylic polyol resin may be 1.03 to 1.07. If it is lower than the above range, physical properties of the coating film such as hardness and water resistance may be deteriorated, and if it is higher than the above range, dry film composition may be lowered.

The curing agent may be diluted with an appropriate solvent, stored in a separate container, and then sufficiently stirred immediately before use. The dilution ratio of the diluent solution of the hardener may be determined by mixing the hydroxyl group of the resin with the isocyanate functional group of the hardener when the mixture of the main mixture and the diluent of the hardener is mixed so that the urethane reaction occurs at the equivalent equivalent. In addition, the mixing ratio may be, for example, 1: 0.9 to 1: 1.2 on the basis of equivalence ratio. If the ratio is more than 1: 1.2, unreacted isocyanate may be generated. If the ratio is less than 1: 0.9, the degree of curing may be lowered.

&Lt; Second Coating Composition >

The second coating composition used in the coating composition for forming a multilayer protective film according to an embodiment of the present invention is a coating composition capable of forming a second coating layer on the first coating layer formed by coating the first coating composition , Whereby the appearance and durability of the coating film can be improved.

According to one embodiment of the present invention, the second coating composition is a two-pack coating composition comprising a third acrylic polyol resin, a polyester polyol resin, and a curing agent, and particularly, a third acrylic polyol The appearance, workability and physical properties of the coating film can be satisfied at the same time through the combination of the polyester polyol resin which can contribute to the scratch resistance of the resin and the coating film and the physical properties of the coating film.

Wherein the second coating composition comprises 20 wt% to 50 wt% of a third acrylic polyol resin, 20 wt% to 60 wt% of a polyester polyol resin, and 10 wt% to 40 wt% of a second solvent, based on the total weight of the second coating composition .

Wherein the third acrylic polyol resin has a solid content of 45 to 55 wt%, a hydroxyl group of 50 to 100 mgKOH / g, a glass transition temperature (Tg) of 20 to 60 DEG C, a weight average molecular weight (Mw) Can be from 15,000 to 20,000 g / mol.

According to an embodiment of the present invention, the amount of the third acrylic polyol resin may be important in order to realize excellent coating appearance and physical properties. For example, the third acrylic polyol resin may be used in an amount of In an amount of 20% by weight to 50% by weight, specifically 20% by weight to 40% by weight. If the content of the third acrylic polyol resin is less than 20% by weight, the appearance of the coated film may become poor and the durability may be deteriorated. If the content of the third acrylic polyol resin is more than 50% by weight, the scratch resistance of the coating film may be deteriorated.

According to one embodiment of the present invention, the monomers used in the third acrylic polyol resin specifically include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate and 1, 2-hydroxybutyl (meth) acrylate, , 6-hexanediol di (meth) acrylate, and mixtures thereof. The acrylic monomer having at least one hydroxyl group may be copolymerized with a monomer such as styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, .

The polyester polyol resin preferably has a solid content of 60 to 80% by weight, a hydroxyl value of 100 to 160 mgKOH / g, a glass transition temperature (Tg) of 0 to 40 ° C, a weight average molecular weight (Mw ) May be 1,500 to 2,500 g / mol.

An example of the polyester polyol resin is a polymer produced by a condensation reaction between a glycol monomer and a monomer having an acid group. Examples of the glycol monomers include neopentyl glycol, trimethylol propane, diethylene glycol, triethylene glycol, 1,6-hexanediol, 1,4-butanediol, 1,4-cyclohexanamitol, And examples of the acid group-containing monomer include terephthalic acid, maleic anhydride, fumaric acid, phthalic anhydride, isophthalic acid, tetrahydrophthalic anhydride, adipic acid and mixtures thereof.

According to one embodiment of the present invention, the amount of the polyester polyol resin may be important in order to realize excellent scratch resistance and physical properties of the coating film. For example, the polyester polyol resin may be added to the total weight of the second coating composition In an amount of 20% by weight to 60% by weight, specifically 30% by weight to 50% by weight. If the content of the polyester polyol resin is less than 20% by weight, the coatability of the coating film may deteriorate. If the content of the polyester polyol resin exceeds 60% by weight, the hardness of the coating film may decrease. .

The weight ratio of the third acrylic polyol resin to the polyester polyol resin may be 1: 1 to 1: 2, specifically 1: 1.5. When the weight ratio is in the above range, the appearance of the coating film is excellent and discoloration of the coating film can be prevented under weathering conditions. If the weight ratio is out of the range, the appearance and weatherability of the coating film may be deteriorated.

Meanwhile, the second solvent included in the second coating composition according to an embodiment of the present invention is used for maintaining the thickness of the coating film and improving the workability of the coating, and is preferably the same as the solvent used in the first coating composition A solvent may be used. In particular, a mixed solvent of an ester solvent and an ether solvent can be used. There is no particular limitation on the amount of the second solvent to be used. However, when the solvent is used in an excessively large amount, the adhesion may be reduced or the durability may deteriorate from the overall physical properties. According to one embodiment of the present invention, the second solvent may be contained in an amount of, for example, 10% by weight to 40% by weight based on the total weight of the second coating composition. More specifically, the second solvent may be contained in an amount of 10% by weight to 30% by weight of the ester solvent and 1% by weight to 10% by weight of the ether solvent.

The second coating composition according to an embodiment of the present invention may further include a surface conditioner to adjust the surface tension of the coating. As the surface conditioner, additives commonly used in the coating composition may be used for controlling the surface tension. For example, a polysiloxane surface conditioner and / or a non-silicone surface conditioner may be used. The amount of the surface modifier to be used is not particularly limited, but may be, for example, 0.1 to 1.0% by weight based on the total weight of the second coating composition. If the amount of the surface modifier is less than 0.1% by weight, the appearance may be deteriorated. If the amount is more than 1.0% by weight, the re-coat adherence may be deteriorated.

Meanwhile, the second coating composition according to an embodiment of the present invention further includes a curing accelerator and an ultraviolet absorber for accelerating the reaction between the third acryl polyol resin and the polyester polyol resin and the curing agent to shorten the drying time of the coating film and shorten the curing time And the components and contents thereof may be the same as those of the first coating composition.

More specifically, according to one embodiment of the present invention, the second coating composition comprises 20 wt% to 40 wt% of a third acrylic polyol resin, 30 wt% to 50 wt% of a polyester polyol resin 1 to 10% by weight of an ester type solvent, 1 to 10% by weight of an ether type solvent, 0.1 to 1% by weight of a surface conditioner, 1 to 10% by weight of an ultraviolet absorbent, and 0.01 to 10% by weight of a curing accelerator, 1% &lt; / RTI &gt; by weight. When the above range is satisfied, the appearance and durability of the coating film can be optimally improved.

On the other hand, the second coating composition may be a polyisocyanate as a curing agent for curing the resin.

In the present invention, the reaction ratio (NCO / OH) of the isocyanate of the polyisocyanate curing agent to the hydroxyl group in the acrylic polyol resin and the polyester polyol resin may be 1.03 to 1.07. If it is lower than the above range, physical properties of the coating film such as hardness and water resistance may be lowered, and if it is higher than the above range, the dry film composition may be lowered.

The curing agent may be diluted with an appropriate solvent, stored in a separate container, and then sufficiently stirred immediately before use. The dilution ratio of the diluent solution of the hardener may be determined by mixing the hydroxyl group of the resin with the isocyanate functional group of the hardener when the mixture of the main mixture and the diluent of the hardener is mixed so that the urethane reaction occurs at the equivalent equivalent. In addition, the mixing ratio may be, for example, 1: 0.9 to 1: 1.2 on the basis of equivalence ratio. If the ratio is more than 1: 1.2, unreacted isocyanate may be generated. If the ratio is less than 1: 0.9, the degree of curing is deteriorated.

According to an embodiment of the present invention, there is provided a multi-layer protective film painted on a metal substrate, the multi-layer protective film sequentially including a first paint layer and a second paint layer on the first paint layer, Wherein the first coating composition comprises 20 wt% to 50 wt% of the first acrylic polyol resin, 20 wt% to 50 wt% of the second acrylic polyol resin, and 10 wt% to 30 wt% of the first solvent, based on the total weight of the coating composition, Wherein the second coating layer comprises 20% by weight to 50% by weight of the third acrylic polyol resin, 20% by weight to 60% by weight of the polyester polyol resin and 10% by weight of the second solvent, based on the total weight of the second coating composition % To 40% by weight of the second coating composition is applied to form a multilayer protective film.

In the multi-layer protective film according to an embodiment of the present invention, the first paint layer is in the range of 15 to 25 μm, specifically 15 to 20 μm, and the second paint layer is 25 to 40 Mu] m, specifically in the range of 30 to 35 [mu] m thickness. Specifically, the thickness ratio of the first paint layer and the second paint layer may be 1: 1 to 1: 3, more specifically, 1: 1.5 to 2.5.

When the thickness of the first coating layer is within the range of the thickness of the first coating layer in the multilayer protective film, the physical properties such as adhesion with the metal substrate, water resistance, chipping resistance and weather resistance can be improved, When the thickness range is satisfied, the appearance and durability of the coating film can be improved.

The present invention also relates to a process for the preparation of a coating composition comprising, on a metal substrate, 20 to 50% by weight of a first acrylic polyol resin, 20 to 50% by weight of a second acrylic polyol resin, Coating and drying a first coating composition comprising from 10% to 30% by weight of a solvent to form a first coating layer, and forming a third coating layer on the primer layer, wherein the third acrylic polyol resin And coating and curing the second coating composition containing from 50% by weight to 50% by weight, from 20% by weight to 60% by weight of the polyester polyol resin and from 10% by weight to 40% by weight of the second solvent to form the second coating layer Layer protective film can be provided.

More specifically, in the method for forming a multilayer protective film, the first coating layer may be formed using a first coating composition having a combination of components in the content range described above. For example, a metal substrate, more specifically, an aluminum foil is placed on a plastic material, and the aluminum foil is pressed on the hot stamping portion where aluminum is adhered to the plastic material, the first coating composition is applied to a dry film thickness of 15 to 25 占 퐉 , And then left at room temperature for 1 minute to 10 minutes to obtain a first coating layer.

Next, the second coating layer may be formed using a second coating composition having a combination of components in the above-described content range. For example, the second coating composition may be applied to the first coating layer at a thickness of 25 to 45 탆 To form a second coating layer, and then curing the final coating film with hot air for about 30 minutes to 60 minutes at about 80 to 90 占 폚, thereby forming a second coating layer on the metal substrate, specifically on hot stamping A protective film can be formed.

The multilayer protective film formed using the paint kit according to an embodiment of the present invention may be formed by sequentially forming a first paint layer and a second paint layer formed by coating a first paint composition and a second paint composition each having a specific component combination It is possible to improve the physical properties of the coating film such as adhesiveness, water resistance, chipping resistance and weather resistance simultaneously. Accordingly, the coating material kit according to one embodiment of the present invention and the multi-layer protective film using the same can be useful as a metal-based protective film, more specifically, as a protective film for a car radiator grill.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

Example

Example 1

Manufacture of paint kits

&Lt; Preparation of first coating composition >

The first coating composition was prepared using the respective components and contents according to the following Table 1.

Specifically, the first acrylic polyol resin and the second acrylic polyol resin were placed in a container and mixed at a low speed using a stirrer. Thereafter, the ultraviolet absorber, the surface modifier, the curing accelerator, and the first solvent were added and stirred for 30 minutes, and the viscosity was adjusted to 59 to 65 KU by using a solvent as required. Then, a first coating composition was prepared by adding a polyisocyanate curing agent (HDI Trimer) to the mixture at a ratio of 1: 1, based on the subject: curing agent. The viscosity of the prepared coating composition was adjusted to 15 - 18 seconds (FORD CUP # 4) with a diluting thinner.

&Lt; Preparation of Second Coating Composition >

A second coating composition was prepared using the respective components and contents according to the following Table 1.

Specifically, the third acrylic polyol resin and the polyester polyol resin were placed in a container and mixed at a low speed using a stirrer. Thereafter, the ultraviolet absorber, the surface modifier, the curing accelerator, and the second solvent were added and stirred for 30 minutes, and the viscosity was adjusted to 59 to 65 KU by using a solvent as necessary. Then, a second coating composition was prepared by adding a polyisocyanate curing agent (HDI Trimer) to the mixture at a ratio of 1: 1 based on the subject: curing agent. The viscosity of the prepared coating composition was adjusted to 15 - 18 seconds (FORD CUP # 4) with a diluting thinner.

&Lt; Preparation of Coating Film Containing Multilayer Protection Film &

The first coating composition was coated on the hot stamping so as to have a dry film thickness of 15 to 20 mu m, and then left at room temperature for 5 minutes to obtain a first coating layer. Next, the second coating material composition was coated on the first coating material layer so as to have a dry film thickness of 30 to 35 탆 and cured by hot air at 80 캜 for 30 minutes to form a second coating material layer, thereby obtaining a final coating film

Example 2

Except that the content of the first acrylic polyol resin and the second acrylic polyol resin was changed in the first coating composition and the content of the third acrylic polyol resin and the polyester polyol resin in the second coating composition were changed as shown in Table 1 below Was obtained in the same manner as in Example 1 to obtain a first coating composition, a second coating composition and a coated film using the same.

Comparative Example 1

Except that the contents of the first acrylic polyol resin and the second acrylic polyol resin in the first coating composition were changed as shown in Table 2 below to obtain the first coating composition, To obtain a coating film using the same.

Comparative Example 2

Except that the content of the first acrylic polyol resin and the second acrylic polyol resin was changed in the first coating composition and the content of the third acrylic polyol resin and the polyester polyol resin in the second coating composition were changed as shown in Table 2 below Was obtained in the same manner as in Example 1 to obtain a first coating composition, a second coating composition and a coated film using the same.

Comparative Example 3

A coating film was obtained in the same manner as in Example 1, except that the first coating layer was coated using only the first coating composition of Example 1 as shown in Table 2 below.

Comparative Example 4

A coating film was obtained in the same manner as in Example 1, except that the second coating layer was coated using only the second coating composition of Example 1 as shown in Table 3 below.

Comparative Example 5

Except that the contents of the third acrylic polyol resin and the polyester polyol resin in the second coating composition were changed as shown in Table 3 below to obtain the first coating composition, the second coating composition and the To obtain a coated film.

Comparative Example 6

Except that the contents of the first acrylic polyol resin and the second acrylic polyol resin in the first coating composition were changed as shown in Table 3 below to obtain the first coating composition, To obtain a coating film using the same.

Comparative Example 7

Except that the contents of the third acrylic polyol resin and the polyester polyol resin in the second coating composition were changed as shown in Table 3 below to obtain the first coating composition, the second coating composition and the To obtain a coated film.

The components in the following Tables 1 to 3 are as follows :

First acrylic polyol resin: 7237-XS-60EN / ETERNAL, 55-65 wt% solids, 65-75 mg KOH / g

Second acrylic polyol resin: CRT01522 / KCC, solid content 45 to 55 wt%, hydroxyl group 50 to 80 mg KOH / g, glass transition temperature (Tg) 30 to 50 DEG C

Third acrylic polyol resin: CRT01522 / KCC, solid content 45 to 55 wt%, hydroxyl group 50 to 80 mg KOH / g, glass transition temperature (Tg) 30 to 50 DEG C

Polyester polyol resin: CRF00279 / KCC, solid content 65 to 75 wt%, hydroxyl group 100 to 130 mg KOH / g, glass transition temperature (Tg) 10 to 30 DEG C

Ultraviolet absorber: Tinuvin 1130 / BASF Hydroxyphenylbenzotriazole

Surface Conditioning Agent A: BYK 358N / BYK Polysiloxane-based surface conditioner

Surface Conditioner B: BYK / BYK 306 Polysiloxane-based surface conditioner

Curing accelerator: dibutyl tin dilaurate, DBTDL / Wuchang Unemployment

Solvents (first and second solvents): A mixture of ethyl acetate (10 wt.%), Butyl acetate (10 wt.%) And butyl cellosolve (6.7 wt.%)

ingredient Example 1 Example 2 The first paint layer
(weight%) The second paint layer
(weight%) The first paint layer
(weight%) The second paint layer
(weight%) The first acrylic polyol resin 35 40 The second acrylic polyol resin 35 30 The third acrylic polyol resin 30 35 Polyester polyol resin 40 35 Ultraviolet absorber 3 1.5 3 1.5 Surface Conditioner A 0.2 0.2 Surface Conditioner B 0.2 0.2 Hardening accelerator 0.1 0.1 0.1 0.1 solvent 26.7 28.2 26.7 28.2

(Unit: wt%) ingredient Comparative Example 1 Comparative Example 2 Comparative Example 3 The first paint layer The second paint layer The first paint layer The second paint layer The first paint layer The second paint layer The first acrylic polyol resin 15 15 35 - The second acrylic polyol resin 55 55 35 - The third acrylic polyol resin 30 25 - Polyester polyol resin 40 45 - Ultraviolet absorber 3 1.5 3 1.5 3 - Surface Conditioner A 0.2 0.2 0.2 - Surface Conditioner B 0.2 0.2 Hardening accelerator 0.1 0.1 0.1 0.1 0.1 - solvent 26.7 28.2 26.7 28.2 26.7 -

(Unit: wt%) ingredient Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 The first paint layer The second paint layer The first paint layer The second paint layer The first paint layer The second paint layer The first paint layer The second paint layer The first acrylic polyol resin - 35 55 35 The second acrylic polyol resin - 35 15 35 The third acrylic polyol resin - 30 15 30 55 Polyester polyol resin - 40 55 40 15 Ultraviolet absorber - 1.5 3 1.5 3 1.5 3 1.5 Surface Conditioner A - 0.2 0.2 0.2 0.2 Surface Conditioner B 0.2 0.2 0.2 Hardening accelerator - 0.1 0.1 0.1 0.1 0.1 0.1 0.1 solvent - 28.2 26.7 28.2 26.7 28.2 26.7 28.2

Experimental Example

Physical properties such as paint workability, appearance of the final coated film, adhesion, water resistance, chipping resistance and weather resistance were measured as follows and evaluated according to the following evaluation criteria using the coating films obtained according to the Examples and Comparative Examples The results are shown in Table 4 below.

<Evaluation Criteria>

◎ - Excellent

○ - Good

△ - Normal

X-defective

1) Painting workability

IWATA was applied to a 30 x 40 cm tin plate twice with 61 reciprocating cycles to compare the degree of atomization and degree of smoothness of the coating and the degree of scratching of the coating.

2) Appearance

The degree of bubbles, foreign matter, spots, grooves, and smoothness on the surface of the coating film were compared.

3) Adhesiveness

Based on the ASTM D3359 tape adhesion test method, the degree of the peeled portion was observed after the tape adhesion test among 100 pieces of 1 mm x 1 mm scale.

4) Water resistance

After the coating film was immersed for 10 days in a 40 ° C thermostat, adhesion test and appearance evaluation were carried out.

5) Chipping resistance

The stones were sprayed at a pressure of 4.0 kgf at a 45 ° angle with a prescribed chipping resistance tester, and the appearance of the coating was visually compared.

6) Weatherability

The appearance, color difference, and adhesion of the film were compared after exposure to 2500 kJ energy in a Xenon weatherometer environment.

Item Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Painting workability ◎ ◎ ◎ ◎ ○ X X X △ Exterior ◎ ◎ ◎ ◎ X ○ ◎ ○ X Attachment ◎ ◎ ○ ○ ○ X △ X ○ Water resistance ◎ ◎ △ △ △ X △ X ○ Chipping resistance ◎ ◎ ◎ ◎ △ X ○ ○ X Weatherability ◎ ◎ ○ ○ △ X ○ △ ○

As shown in Table 4, the coating films to which the protective coatings prepared using the first coating composition and the second coating composition of Examples 1 and 2 according to the present invention were applied had excellent coating workability and appearance, Durability and durability. On the other hand, in the case of the coating film to which the protective film of Comparative Examples 1 to 7 was applied, the appearance and workability of the coating film were excellent, but physical properties such as adhesion, water resistance and weather resistance were poor.

Specifically, a first coating composition containing first and second acrylic polyol resins within a specific content range, and a second coating composition containing a third acrylic polyol resin and a polyester polyol resin within a specific content range, The coating films of Examples 1 and 2 were excellent in physical properties of the coating film but in Comparative Examples 1 and 2 coated with the first coating composition deviating from the content range of the present invention, And the water resistance is greatly reduced. Comparative Example 3 in which only the first paint layer was present and Comparative Example 4 in which only the second paint layer was present showed poor paint workability, appearance, adhesion, water resistance, chipping resistance and weather resistance have.

Comparative Example 5 in which the second paint layer is out of the content range of the present invention and Comparative Example 5 in which the first and second acrylic polyol resins are out of the content range of the present invention in the first paint composition, In Comparative Example 7, in which the third acrylic polyol resin and the polyester polyol resin were out of the content range of the present invention in the coating composition, all of them were inferior to those of Comparative Example 5 in which the final appearance was comparatively excellent, It was confirmed that it had physical properties.

Claims (10)

Wherein the first acrylic polyol resin comprises 20% by weight to 50% by weight of the first acrylic polyol resin, 20% by weight to 50% by weight of the second acrylic polyol resin and 10% by weight to 30% by weight of the first solvent, A coating composition; And
A second paint comprising 20 wt% to 50 wt% of a third acrylic polyol resin, 20 wt% to 60 wt% of a polyester polyol resin, and 10 wt% to 40 wt% of a second solvent, based on the total weight of the second paint composition The composition
Layer coating film for forming a protective layer.
The method according to claim 1,
Wherein the mixing ratio of the first acrylic polyol resin to the second acrylic polyol resin is 1: 1 to 1: 2 by weight.
The method according to claim 1,
Wherein the mixing ratio of the third acrylic polyol resin to the polyester polyol resin is 1: 1 to 1: 2 by weight.
The method according to claim 1,
Wherein the first acrylic polyol resin has a solid content of 55 to 65 wt% and a hydroxyl group of 60 to 75 mg KOH / g,
Wherein the second acrylic polyol resin has a solid content of 45 to 55 wt%, a hydroxyl group of 50 to 100 mg KOH / g, and a glass transition temperature (Tg) of 20 to 60 DEG C. Kits.
The method according to claim 1,
Wherein the third acrylic polyol resin has a solid content of 45 to 55 wt%, a hydroxyl group of 50 to 100 mg KOH / g, a glass transition temperature (Tg) of 20 to 60 DEG C,
Wherein the polyester polyol resin has a solid content of 60 to 80% by weight, a hydroxyl group of 100 to 160 mgKOH / g, and a glass transition temperature (Tg) of 0 to 40.
The method according to claim 1,
Wherein each of the first coating composition and the second coating composition further comprises 0.01 to 1 wt% of a curing accelerator, 0.1 to 1 wt% of a surface conditioner, and 1 wt% to 10 wt% of an ultraviolet absorber.
The method of claim 6,
Wherein the surface modifier is a polysiloxane-based compound.
The method according to claim 1,
Wherein the first solvent and the second solvent each comprise an ester solvent, an ether solvent or a mixed solvent thereof.
As a multilayer protective film which is coated on a metal substrate and sequentially includes a primer layer 1 paint layer and a clear layer 2 paint layer on the primer layer 1 paint layer,
Wherein the primer layer 1 paint layer comprises 20 wt% to 50 wt% of the first acrylic polyol resin, 20 wt% to 50 wt% of the second acrylic polyol resin, and 10 wt% of the first solvent, based on the total weight of the primer coating composition first coating composition, To 30% by weight of the primer coating composition. The primer coating composition is a layer formed by coating the first coating composition,
Wherein the clear layered paint 2 coating layer comprises 20 wt% to 50 wt% of the third acrylic polyol resin, 20 wt% to 60 wt% of the polyester polyol resin, and 10 wt% to 5 wt% of the second solvent composition relative to the total weight of the clear paint composition second coating composition And 40 wt% of the second coating composition.
The method of claim 9,
Wherein the primer layer 1 paint layer is in a thickness of 15 to 25 占 퐉 and the clear layer 2 paint layer is in a thickness of 25 to 40 占 퐉.