KR102567352B1 - Clear paint composition - Google Patents

Abstract

The present invention relates to a transparent coating composition. The transparent coating composition of the present invention includes 25 to 35 parts by weight of an acrylic polyol resin, 40 to 50 parts by weight of two types of polyester polyol resins having different solid content, 0.1 to 1 part by weight of a hardening accelerator, and 20 to 30 parts by weight of a solvent. By doing so, it is characterized in that a coating film having excellent appearance and scratch resistance is formed while maintaining excellent physical properties such as water resistance and weather resistance.

Description

Clear paint composition {Clear paint composition}

The present invention relates to a transparent coating composition.

As automobiles become more advanced, the level and requirements of consumers are gradually increasing. Among them, scratches are an item that is mentioned as a customer complaint every year and must be improved in order to improve the appearance and luxury. In order to prevent scratches on exterior parts of automobiles, scratch-resistant paint is usually used to paint a multi-layer coating consisting of a primer-base-transparent paint on materials such as ABS, PC+PBT, and the like.

In addition, there is an increasing trend of high-gloss black painted parts for exterior use to improve the quality of the exterior. High-gloss specifications tend to have a lot of scratches, especially scratches on black color that are easily visible to the naked eye.

Accordingly, in order to improve the scratch resistance of the transparent paint, a method of preventing scratches by increasing the hardness of the coating film by using an acrylic resin having a high glass transition temperature (Tg) is known, but this method is known to have poor impact resistance of the coating film. there is a problem. In addition, a method of preventing scratches by increasing hardness by mixing a reinforcing filler such as silica has also been developed, but this method has limitations in realizing high gloss.

Therefore, there is a continuing demand for the development of a transparent paint capable of forming a coating film with excellent external appearance while still having excellent scratch resistance (particularly, exhibiting excellent scratch resistance even in a highly glossy black color).

An object of the present invention is to provide a transparent paint composition having excellent external appearance and scratch resistance while maintaining excellent physical properties such as water resistance and weather resistance of a formed coating film.

In order to achieve the above object, the present invention contains 25 to 35 parts by weight of an acrylic polyol resin, 40 to 50 parts by weight of two types of polyester polyol resins having different solid content, 0.1 to 1 part by weight of a curing accelerator, and 20 to 20 parts by weight of a solvent. It provides a transparent paint composition containing 30 parts by weight.

When the transparent coating composition of the present invention is used, it is possible to form a coating film having excellent external appearance and scratch resistance while maintaining excellent physical properties such as water resistance and weather resistance. Therefore, even when used for black painting, it maintains high gloss and has excellent scratch resistance, so it can show the effect of improving product quality.

Hereinafter, the present invention will be described in detail.

The transparent coating composition of the present invention includes 25 to 35 parts by weight of an acrylic polyol resin, 40 to 50 parts by weight of two types of polyester polyol resins having different solid content, 0.1 to 1 part by weight of a hardening accelerator, and 20 to 30 parts by weight of a solvent. do.

acrylic polyol resin

The transparent paint composition of the present invention includes an acrylic polyol resin as a main component. The acrylic polyol resin as described above may impart strength to a coating film formed using the transparent coating composition.

As the monomer of the acrylic polyol resin, an acrylic monomer having at least one hydroxyl group may be used, and more specifically, but not limited thereto, for example, 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate rate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, or a mixture thereof may be used. The acrylic polyol resin formed using the monomers may be a resin formed from one of the monomers, or a blend or copolymer thereof.

In addition, the acrylic polyol resin has a solid content of 35 to 70% by weight, for example, 40 to 65% by weight, 45 to 60% by weight, another example of 50 to 55% by weight, and a weight average molecular weight of 8,000 to 14,000g / mol, for example, 8,500 to 13,500 g/mol, another example may be 9,000 to 13,000 g/mol, or 10,000 to 12,000 g/mol. When the solid content and weight average molecular weight of the acrylic polyol resin are less than the above range, the appearance may be deteriorated due to the decrease in oiliness, and when the solid content and weight average molecular weight of the acrylic polyol resin exceed the above range, the smoothness of the coating film this may deteriorate.

The acrylic polyol resin may have a hydroxyl value of 110 to 150 mgKOH/g, for example, 115 to 135 mgKOH/g, 120 to 135 mgKOH/g, or 125 to 135 mgKOH/g. When the hydroxyl value of the acrylic polyol resin is less than 110 mgKOH/g, the drying property of the coating film may decrease and the hardness may decrease. Durability and weatherability may be reduced.

It may be preferable to use an acrylic polyol having a glass transition temperature (Tg) of 20 to 50° C., for example, 30 to 40° C. in terms of physical properties and scratch resistance of the formed coating film. For example, when the glass transition temperature of the acrylic polyol is less than 20° C., scratch resistance may decrease, and when the glass transition temperature exceeds 50° C., pencil hardness of the coating film may deteriorate.

The acrylic polyol resin may be included in an amount of 25 to 35 parts by weight. When the acrylic polyol resin is included within the above range, the effect of improving the physical properties and scratch resistance of the formed coating film may be particularly excellent. For example, if the content is less than the above range, scratch resistance of a coating film formed using the same may be poor, and if the content exceeds the above range, problems such as deterioration in gloss and poor workability of the coating film may appear.

polyester polyol resin

The transparent paint composition of the present invention may include a polyester polyol resin as a main component. By using the polyester polyol resin as described above, the appearance of a coating film formed using the transparent coating composition can be improved. In particular, the transparent coating composition of the present invention can improve the appearance and workability of the formed coating film by including two types of polyester polyol resins having different solid contents.

More specifically, the two types of polyester polyol resins may include a first polyester polyol resin and a second polyester polyol resin.

The first polyester polyol resin has a solid content of more than 80% by weight and less than or equal to 100% by weight, for example, 85 to 100% by weight, 90 to 100% by weight, and another example is 95 to 100% by weight, 96 to 100% by weight And, the number average molecular weight may be 500 to 1,200 g / mol, for example, 530 to 1,175 g / mol, 600 to 1,000 g / mol, 700 to 900 g / mol. When the solid content and number average molecular weight of the first polyester polyol are less than the above ranges, the coating film may be light-repellent.

The first polyester polyol may have a hydroxyl value of 120 to 160 mgKOH/g, for example, 130 to 150 mgKOH/g or 135 to 145 mgKOH/g. When the hydroxyl value of the first polyester polyol is less than 120 mgKOH/g, the drying property may decrease and the hardness of the coating film may decrease, and when the hydroxyl value exceeds 160 mgKOH/g, the coating film is not sufficiently cured. Properties, water resistance, scratch resistance and weather resistance may be deteriorated. The first polyester polyol resin has excellent self-healing properties when forming a coating film, and thus scratch resistance can be greatly improved by using the first polyester polyol resin.

The second polyester polyol resin has a solid content of 20% by weight or more and 80% by weight or less, for example, 25 to 75% by weight, 30 to 65% by weight, 35 to 60% by weight, 40 to 55% by weight, 40 to 50% by weight % by weight, with a weight average molecular weight of 2,500 to 8,000 g/mol, such as 2,850 to 7,500 g/mol, 3,000 to 7,000 g/mol, 4,000 to 6,000 g/mol, or 4,500 to 55,00 g/mol can be When the solid content and weight average molecular weight of the second polyester polyol are out of the above ranges, the lightening property, smoothness and appearance of the coating film may be deteriorated.

The second polyester polyol may have a hydroxyl value of 120 to 160 mgKOH/g, for example, 120 to 155 mgKOH/g, 125 to 150 mgKOH/g, or 130 to 145 mgKOH/g. If the hydroxyl value of the second polyester polyol is less than 120 mgKOH/g, the drying property may decrease and the hardness of the coating film may decrease, and if the hydroxyl value exceeds 160 mgKOH/g, the coating film is not sufficiently cured, and thus the coating Properties, water resistance, scratch resistance and weather resistance may be deteriorated.

The second polyester polyol resin has an excellent appearance when forming a coating film, and thus the smoothness of the coating film can be greatly improved by using the second polyester polyol resin.

The first polyester polyol resin and the second polyester polyol resin may be used in a weight ratio of 1:1.5 to 1:4.5. When the ratio of the first polyester polyol resin and the second polyester polyol resin is less than 1:1.5, appearance and smoothness may be deteriorated because the second polyester polyol resin is used relatively less. When the ratio of the first polyester polyol resin and the second polyester polyol resin exceeds 1:4.5, scratch resistance may deteriorate due to the use of a relatively small amount of the first polyester.

The polyester polyol resin is not limited thereto, but for example, polyether polyurethane, polyester polyurethane, polycarbonate polyurethane, polyether ester polyurethane, polyether carbonate polyurethane, polycaprolactone polyurethane, hydrocarbon poly Urethanes, aliphatic polyurethanes, aromatic polyurethanes, and mixtures thereof may be used.

The polyester polyol resin may be included in an amount of 40 to 50 parts by weight based on 25 to 35 parts by weight of the acrylic polyol resin. When the polyester polyol resin is included within the above range, the effect of improving the appearance properties of the formed coating film may be particularly excellent. For example, when the content is less than the above range, the effect of improving the appearance of a coating film formed using the same is insignificant, and when the content exceeds the above range, a problem of poor hardness of the coating film may occur.

The transparent coating composition of the present invention improves the appearance and resistance of a coating film by using together the acrylic polyol resin and the polyester polyol resin, more specifically the acrylic polyol resin and two types of polyester resins having different solid contents as described above. Physical properties such as scratch resistance, hardness, and weather resistance can be greatly improved.

hardening accelerator

The transparent coating composition of the present invention may improve the curing performance of the coating composition by including a curing accelerator.

The curing accelerator is commonly used in the art, but a known curing accelerator may be used, for example, dibutylbis[(1-oxododecyl)oxy]stannein (Dibutylbis[(1-oxododecyl)oxy ]stannane, DBTDL, TL-100), tin compounds such as dibutyltin dilaurate, dibutyltin diacetate, diethyltin diacetate, dihexyltin diacetate, 2-methyl imidazole, 2-phenyl imidazole imidazoles such as dazole, ethyl methyl imidazole, 2-ethyl imidazole, 1-benzyl 2-methylimidazole, 2-butyl imidazole, triphenyl phosphine, benzyltriphenylphosphonium chloride, butyltriphenylphos Quaternary ammoniums such as phonium chloride and tetraphenylphosphonium chloride or mixtures thereof may be used. Preferably, dibutylbis[(1-oxododecyl)oxy]stannane, dibutyltin dilaurate or a mixture thereof may be used.

The curing accelerator may include the curing accelerator in an amount of 0.1 to 1 part by weight based on 25 to 35 parts by weight of the acrylic polyol resin. When the curing accelerator is included in an amount less than the above range, the curability of the coating composition may deteriorate, and when the content exceeds the above range, storage stability of the coating composition may deteriorate.

solvent

In the present invention, as a solvent for maintaining the thickness of a coating film and improving painting workability, a solvent commonly used in a transparent paint composition may be used.

Examples of the solvent include, but are not limited to, non-polar solvents such as n-heptane, toluene, xylene, petroleum compounds, and n-hexane; Ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, dibasic esters, 3-methoxy butyl acetate, amyl acetate, butyl glycol acetate, butyl cellosolve acetate, polar solvents such as methyl ethyl ketone, methyl isobutyl ketone, acetone, diisobutyl ketone, isophorone and cyclohexanone; And at least one of these mixtures may be appropriately selected and used according to the properties or volatility of the resin used.

In one aspect, the solvent may use at least one selected from the group consisting of ester-based solvents, hydrocarbon-based solvents, and glycol-based solvents.

The solvent may be 20 to 30 parts by weight based on 25 to 35 parts by weight of the acrylic polyol resin. If the content of the solvent is too high, problems such as poor overall physical properties, such as reduced adhesion and durability of the formed coating film, may occur, and if the solvent is used in a small amount, it is difficult to expect the effect of using the solvent. .

The transparent coating composition of the present invention contains 25 to 35 parts by weight of the acrylic polyol resin described above, 40 to 50 parts by weight of two types of polyester polyol resins having different solid content, 0.1 to 1 part by weight of a curing accelerator, and 20 to 30 parts by weight of a solvent. Including as a composition of wealth. If the composition is out of the above range, the effect of the transparent coating composition is poor.

curing agent

The transparent coating composition of the present invention may further include a curing agent. More specifically, it may be prepared in a form that can be used by mixing the curing agent immediately before using the transparent paint composition, or in a form that is already mixed.

The curing agent is preferably used including an isocyanate-based curing agent. By using an isocyanate-based curing agent, a strong polyurethane coating film can be formed due to the combination of an isocyanate group in the curing agent and a hydroxyl group in the resin.

The curing agent is such that the molar ratio of the total hydroxy groups in the acrylic polyol resin and the two types of polyester polyol resins and the isocyanate groups in the curing agent is 1:1 to 1.5 (OH:NCO), for example 1:1.03 to 1.07. content may be included. For example, when using hexamethylene diisocyanate trimer (HDI trimer) as the curing agent, 2 to 5: 1 based on the total weight of the acrylic polyol resin and two types of polyester polyol resin (resin: curing agent ), for example, it may be included in an amount that is a weight ratio of 2 to 3: 1.

Other Additives

The transparent paint composition of the present invention may further include additives commonly used in transparent paint compositions such as a surface conditioner and an ultraviolet absorber within a range that does not impair the object of the present invention.

The surface conditioner may be added to adjust the surface tension of the paint, and may include, but is not limited to, at least one selected from the group consisting of polysiloxane-based compounds and non-silicone-based compounds.

The polysiloxane-based compound is, but is not limited to, for example, polydimethylsiloxane, polyether-modified polydimethylsiloxane, polyether-modified methylpolysiloxane, polymethylalkylsiloxane, silicone oil, silicone-based surfactant, silicone-based synthetic lubricating oil, or mixtures thereof. can be used.

The non-silicone-based compound is not limited thereto, but for example, polyacrylate, lower alcohol, mineral oil, oleic acid, polypropylene glycol, glycerin higher fatty acid esters, and fluorine-containing surfactants may be used as mixtures thereof.

The UV absorber may be added to improve problems such as discoloration of paint, swelling of formed coating film, peeling between layers, and loss of gloss, but is not limited thereto. For example, known ultraviolet rays such as hydroxyphenyl benzotriazole Absorbents may be used.

The additives may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the transparent paint composition.

Hereinafter, examples and the like will be described in detail to aid understanding of the present invention. However, the embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the following examples. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Examples and Comparative Examples

[Preparation of transparent coating composition]

At 25 ° C., put the first polyester polyol resin, the second polyester polyol resin and the acrylic polyol resin in the composition and content shown in Tables 1 to 3 below in a 1000 mL tin can or plastic container, using a stirrer A homogeneous mixture was prepared by stirring at a speed of 700 rpm for 30 minutes. Thereafter, a UV absorber, a surface conditioner, a curing accelerator and a solvent were added and stirred for 30 minutes to prepare a transparent paint composition. The solvent was added so that the viscosity of the composition was 24 to 30 SEC.

Ingredients (g) Example One 2 3 4 5 6 7 1-1 polyester polyol 9 9 15 11 12 - - 2-1 polyester polyol 36 34 30 28 36 36 34 1-2 polyester polyol - - - - - 9 - 1-3 polyester polyol - - - - - - 9 2-2 polyester polyol - - - - - - 2-3 polyester polyol - - - - - - - Acrylic polyol resin 1-1 28 28 28 33 25 28 28 Acrylic polyol resin 1-2 - - - - - - - Acrylic polyol resin 1-3 - - - - - - - UV absorber 1.7 1.7 1.7 1.7 1.7 1.7 1.7 hardening accelerator 0.15 0.15 0.15 0.15 0.15 0.15 0.15 surface conditioner 0.2 0.2 0.2 0.2 0.2 0.2 0.2 solvent 24.95 26.95 24.95 25.95 24.95 24.95 26.95 Tot. 100 100 100 100 100 100 100

Ingredients (g) Example 8 9 10 11 12 13 14 15 1-1 polyester polyol 10 9 9 10 - - 7.5 9 2-1 polyester polyol - - 34 35 - - 38 36 1-2 polyester polyol - - - - 9 - - - 1-3 polyester polyol - - - - - 9 - - 2-2 polyester polyol 35 - - - 36 - - - 2-3 polyester polyol - 36 - - - 34 - - Acrylic polyol resin 1-1 28 28 - - - - 26.5 28 Acrylic polyol resin 1-2 - - 28 - 28 - - - Acrylic polyol resin 1-3 - - - 28 - 28 - - UV absorber 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 hardening accelerator 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 surface conditioner 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 solvent 24.95 24.95 26.95 24.95 24.95 26.95 25.95 24.95 Tot. 100 100 100 100 100 100 100 100

Ingredients (g) comparative example One 2 3 4 5 6 7 1-1 polyester polyol 9 6 11 10.8 7.2 16 - 2-1 polyester polyol 36 24 44 43.2 28.8 37 45 acrylic polyol resin 28 42 15 33.6 22.4 15 28 UV absorber 1.7 1.7 2 2.04 1.36 2 1.7 hardening accelerator 1.5 0.15 0.15 0.18 0.12 One 0.15 surface conditioner 0.2 0.1 0.2 0.24 0.16 One 0.2 solvent 23.6 26.05 27.65 9.94 39.96 28 24.95 Tot. 100 100 100 100 100 100 100

1-1 polyester polyol: solid content 96% by weight, hydroxyl value 140 mgKOH / g, number average molecular weight: 800 g / mol

1-2 polyester polyol: solid content 100% by weight, hydroxyl value 149 mgKOH / g, number average molecular weight: 1,175 g / mol

1-3 polyester polyol: solid content 96% by weight, hydroxyl value 133 mgKOH / g, number average molecular weight: 530 g / mol

2-1 polyester polyol: solid content 45% by weight, hydroxyl value 132 mgKOH / g, weight average molecular weight: 5,050 g / mol

2-2 polyester polyol: solid content 40% by weight, hydroxyl value 130 mgKOH / g, weight average molecular weight: 2,850 g / mol

2-3 polyester polyol: solid content 50% by weight, hydroxyl value 144 mgKOH / g, weight average molecular weight: 7,500 g / mol

Acrylic polyol 1-1: solid content 52% by weight, hydroxyl value 130 mgKOH / g, Tg 35 ° C, weight average molecular weight: 11,000 g / mol

Acrylic polyol 1-2: Solid content 50% by weight, hydroxyl value 120 mgKOH / g, Tg 31 ° C, weight average molecular weight: 8,500 g / mol

Acrylic polyol 1-3: Solid content 55% by weight, hydroxyl value 138 mgKOH / g, Tg 38 ° C, weight average molecular weight: 13,500 g / mol

Surface conditioner: Polyetherpolysiloxane-based surface conditioner (Polyetherpolysiloxane, Borchi Gol OL17, OMG BORCHERS GMBH)

UV absorber: (TINUVIN 5151, BASF AKTIENGESELLSCHAFT)

Curing accelerator: (Dibutylbis[(1-oxododecyl)oxy]stannane, TL-100, SONGWON INDUSTRIAL Co.)

Solvent: XYLENE

test example

After mixing the curing agent (HDI trimer) so that the weight ratio of the resin and the curing agent in the transparent paint composition prepared above is 2.5: 1, the viscosity (Ford Cup # 4) 14 using a diluent (0278 (JY), KCC) to 16 SEC. Painting was carried out using the diluted composition.

First, after coating materials such as ABS, PC+PBT, etc. with an oil-soluble primer (RP2143(H), KCC Co.) to a dry film thickness of 10 to 14 micrometers, it was dried at room temperature for 6-8 minutes. Thereafter, the oil-soluble black base coat (UT578(A)-EB, KCC Co.) was applied on the formed film to a dry film thickness of 25 to 35 micrometers, and then dried at room temperature for 8-10 minutes. Thereafter, the diluted composition prepared above was applied on the formed coating film to a dry coating thickness of 28 to 38 micrometers, and then cured in 70 ° C hot air for 30 minutes to form a final coating film.

[Painting workability]

On a tin plate of 30 x 40 cm, IWATA 61 cases were applied twice in a round-trip to evaluate the degree of atomization, smoothness, and lightness of the paint during coating.

[Exterior]

After painting the paint on the plastic material coated with the primer, drying it for 8-10 minutes at 70 ℃, and then painting the transparent paint prepared above on it, the degree of air bubbles, foreign matter, spots, grooves and smoothness of the surface evaluated.

[Adhesion]

According to the ASTM D3359 tape adhesion test method, the extent of the peeled portion was observed after the tape adhesion test among 100 1 mm x 1 mm scales.

[water resistance]

The coating film specimen prepared above was immersed for 10 days in a 40 ° C. constant temperature bath, and then an adhesion test and appearance evaluation were performed.

[Scratch resistance]

Using an AMTEC KISTLER car washability tester, the coating film specimen prepared above was mounted on a test bench and reciprocated 10 times at a specimen moving speed of 5 m/min.

Gloss retention (%) = gloss after evaluation / gloss before evaluation * 100 (%)

[weather resistance]

After exposure to the prepared coating film specimen with energy of 2500 kJ in a xenon weatherometer tester environment, the appearance, color difference, and adhesion of the coating film were evaluated.

[Hardness]

On the test piece, apply force using a standard pencil (pencil hardness 2B ~ HB) to draw a straight line about 5 cm, and then check the surface condition of the coating film.

The evaluation results are shown in Tables 3 and 4 below.

Property evaluation Example One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Painting workability ◎ ◎ ○ ◎ ◎ ◎ ○ ○ ○ ◎ ◎ ○ ○ △ ◎ Exterior ◎ ◎ ○ ◎ ◎ ◎ ○ ○ ○ ◎ ◎ ○ ○ △ ○ adhesiveness ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ ○ ◎ ○ ○ ◎ ◎ ◎ water resistance ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ ○ ◎ ○ ○ ◎ ◎ ◎ scratch resistance ○ ◎ ◎ ◎ ◎ ○ ○ ◎ ○ ○ ○ ○ ○ ○ △ weatherability ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ○ ◎ ○ ○ ◎ ◎ ◎ Hardness ◎ ◎ ◎ ◎ ◎ ◎ ○ ○ ◎ ○ ○ ○ ○ ○ ○ Evaluation: ◎-Excellent, ○-Good, △-Average, X-Poor

Property evaluation comparative example One 2 3 4 5 6 7 Painting workability △ X X X X ○ ○ Exterior △ △ △ X X ○ X adhesiveness ◎ ◎ ◎ ◎ ◎ ◎ ◎ water resistance ◎ ◎ ◎ ○ ○ ◎ ○ scratch resistance X X X X X ◎ X weather resistance ◎ ◎ ○ ◎ ◎ △ ◎ Hardness ○ ○ ○ ○ ○ ○ ○ Evaluation: ◎-Excellent, ○-Good, △-Average, X-Poor

As can be seen in Tables 4 and 5, the coating film prepared using the transparent coating composition of the present invention had excellent physical properties such as painting workability, appearance, adhesion, water resistance, scratch resistance, and weather resistance.

Claims (4)

25 to 35 parts by weight of an acrylic polyol resin;
40 to 50 parts by weight of two kinds of polyester polyol resins having different solid contents;
0.1 to 1 part by weight of a curing accelerator; and
Contains 20 to 30 parts by weight of a solvent;
The two types of polyester polyol resins include a first polyester polyol resin and a second polyester polyol resin,
The first polyester polyol resin has a solid content of more than 80% by weight and less than or equal to 100% by weight, a number average molecular weight of 500 to 1,200 g / mol, and a hydroxyl value of 120 to 160 mgKOH / g,
The second polyester polyol resin has a solid content of 20% by weight or more and 80% by weight or less, a weight average molecular weight of 2,500 to 8,000g / mol, and a hydroxyl value of 120 to 160 mgKOH / g. The method of claim 1,
The acrylic polyol resin has a solid content of 35 to 70% by weight, a weight average molecular weight of 8,000 to 14,000 g / mol, a hydroxyl value of 110 to 150 mgKOH / g, and a glass transition temperature (Tg) of 20 to 50 ° C. Clear paint composition. delete The method of claim 1,
A weight ratio of the first polyester polyol resin and the second polyester polyol resin is 1:1.5 to 1:4.5.