KR20190090280A - Clear paint composition - Google Patents

Abstract

The present invention relates to a one-component clear paint composition: comprising at least one acrylic polyol resin; a modified acrylic polyol resin produced by the reaction of a glycidyl ester with an acrylic resin having a carboxyl group and a hydroxyl group; and a curing agent. The clear paint composition is excellent in weather resistance and chipping resistance.

Description

Clear paint composition {CLEAR PAINT COMPOSITION}

The present invention relates to a clear coating composition.

The automotive coating system can be classified into a middle coat, which basically determines the mechanical properties depending on the characteristics, a top coat on which color and appearance are important, and a top coat which can complement the final gloss, clearness and mechanical properties of the automobile.

In general, the topcoat clearcoat composition applied to an automobile body is composed of a hydroxyl group-containing acrylic resin, a melamine resin and a block isocyanate resin, and additives such as a smoothing agent, a slip agent, an ultraviolet absorber and an antioxidant, Liquid type clear paint is widely used. However, in the case of a clear paint prepared using an existing hydroxyl group-containing acrylic resin, there is a disadvantage that the paint adhesion on the water-soluble base paint is poor and the chemical resistance such as acid rain is weak. Korean Patent No. 576,447 discloses a method for improving the acid resistance of a conventional acrylic polyol resin, melamine resin, block isocyanate, and paint while maintaining the curing system. Minimizes the melamine content, maximizes the content of characteristic block isocyanate, and exerts excellent effects in acid resistance and recoat adhesion by applying epoxy resin, has excellent scratch resistance and water resistance, and minimizes yellowing due to impurities And developed an automotive solvent type one-component transparent top coating composition excellent in acid resistance and coating film appearance quality. However, the one-component clearcoat system using the epoxy functional group has a fundamental problem that the stability of the acid-epoxy itself is poor and the storage stability is poor, and gradually becomes gelled when not used immediately after the production. Also, when applied to a water-soluble topcoat, the water-soluble topcoat may react with an amine applied to the basecoat to cause yellowing.

Korean Patent Laid-Open No. 2006-0119012 discloses a method for solving the problem of a one-component transparent top coating, which comprises a main part containing an acrylic polyol main resin containing a hydroxyl group, an acrylic polyol auxiliary resin having a diurea group and a solvent and a hexamethylene diisocyanate tri 2-part type automotive coating composition comprising a curing agent part containing an isophorone diisocyanate trimer, an isophorone diisocyanate trimer and a solvent. This composition can impart excellent appearance and mechanical properties, compatibility with a water-soluble topcoat, delamination and clarity. However, the two-part clear paint is harmful to health by the use of isocyanate, and when it is exposed to moisture, undesired side reaction may occur due to moisture and there is a disadvantage that the pot life is short.

Accordingly, many technical developments have been made to improve the appearance and mechanical properties of the top clearcoat.

Korean Patent Publication No. 2006-0052309

The present invention provides a clear coating composition.

The present invention provides a one-pack clear coating composition comprising at least one acrylic polyol resin, a modified acrylic polyol resin produced by the reaction of an acrylic resin having a carboxyl group and a hydroxyl group with glycidyl ester, and a curing agent.

The clear coating composition according to the present invention is excellent in weather resistance and chipping resistance and is superior in image clarity and scratch resistance in high gloss coating as compared with conventional one-pack coating compositions.

Hereinafter, the present invention will be described in detail.

The present invention provides a clear coating composition.

The clear coating composition of the present invention comprises at least one acrylic polyol resin, a modified acrylic polyol resin produced by the reaction of an acrylic resin having a carboxyl group and a hydroxy group with glycidyl ester, and a curing agent.

Hereinafter, the configurations will be described in detail.

≪ Acrylic polyol resin &

The clear coating composition of the present invention comprises at least one acrylic polyol resin.

The acrylic polyol resin used in the present invention can improve the appearance and mechanical properties of the coating.

The acrylic polyol resin may be polymerized using an acrylic monomer containing a hydroxyl group. The hydroxy group-containing acrylic monomer may be, for example, monohydroxyalkyl (meth) acrylate, dihydroxyalkyl (meth) acrylate, lactone (meth) acrylate, hydroxy alicyclic . (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, (Meth) acrylate, 2-hydroxyethyleneglycol (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, Hydroxypropyl acrylate, hydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, 4-hydroxymethylcyclohexylmethyl acrylate, 1,6-hexanediol di (meth) acrylate and the like.

The hydroxy group-containing acrylic monomer may be copolymerized with a monomer such as styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate or mixtures thereof.

The content of the acrylic polyol resin may be 30 wt% to 70 wt%, 30 wt% to 60 wt%, or 30 wt% to 50 wt% based on the total weight of the clear coating composition. When the content of the acrylic polyol resin is less than 30% by weight, the chemical properties such as chemical resistance are impaired and the appearance improving effect is poor. When the content exceeds 70% by weight, the coating film becomes too hard, .

The glass transition temperature (T _g ) of the acrylic polyol resin may be 10 ° C to 50 ° C. If the glass transition temperature is lower than 10 ° C, the dryness of the coating film may become poor. If the glass transition temperature is higher than 50 ° C, the hardness of the coating film may increase, and the impact resistance may be weakened.

The acrylic polyol resin of the present invention may comprise two or more kinds of acrylic polyol resins having different viscosities, wherein the two acrylic polyol resins have a first acrylic polyol resin having a viscosity of 950 cP to 2,400 cP and a second acrylic polyol resin having a viscosity of 20 lt; RTI ID = 0.0 > cP < / RTI > to 55 cP.

The first acrylic polyol resin acts as a main resin in the clear coating composition and has an acid value of 5 mgKOH / g to 15 mgKOH / g, a hydroxyl value of 120 mgKOH / g to 170 mgKOH / g, a glass transition temperature of 10 Deg.] C to 20 < 0 > C, and the weight average molecular weight may be 10,000 g / mol to 30,000 g / mol, but is not limited thereto. In addition, the first acrylic polyol resin may have a solid content of 55% by weight to 70% by weight and 58% by weight to 61% by weight.

The first acrylic polyol resin may be contained in an amount of 20 wt% to 69.9 wt%, 20 wt% to 69 wt%, and 25 wt% to 69 wt% based on the total weight of the clear paint composition. When the content of the first acrylic polyol resin is less than 20% by weight, the chemical properties such as chemical resistance are deteriorated. When the content is more than 69.9% by weight, the coating film becomes too hard, have.

The second acrylic polyol resin acts as a leveling agent in the clear paint composition and has an acid value and a hydroxyl value of 0 mgKOH / g, a glass transition temperature of 10 ° C to 50 ° C, a weight average molecular weight of 3,000 g / mol to 15,000 g / mol , And the solid content may be 40 wt% to 60 wt% and 49 wt% to 51 wt%.

The second acrylic polyol resin may be contained in an amount of 0.1% by weight to 30% by weight based on the total weight of the clear paint composition, and may be contained in an amount of 1% by weight to 10% by weight and 1% by weight to 5% by weight. If the content of the second acrylic polyol resin is less than 0.1% by weight, the surface of the paint may not be smooth and the appearance may become poor. When the content is more than 30% by weight, the physical properties of the coating film may be deteriorated.

≪ Modified acrylic polyol resin >

The clear coating composition of the present invention comprises a modified acrylic polyol resin.

The modified acrylic polyol resin is added as an auxiliary resin in the clear paint composition in addition to the above-mentioned one or more acrylic polyol main resins to improve the gloss, image clarity (DOI) and scratch resistance of the formed coating film.

The modified acrylic polyol resin may be produced by the reaction of an acrylic resin having a carboxyl group and a hydroxyl group with a glycidyl ester.

The acrylic resin having a carboxyl group and a hydroxy group may be prepared by polymerizing an ethylenically unsaturated monomer, a non-functional acrylic monomer, an acrylic monomer containing a carboxyl group, and an acrylic monomer containing a hydroxy group.

The ethylenically unsaturated monomer may be selected from the group consisting of styrene, methyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, benzyl (meth) acrylate, isobonyl (meth) acrylate, lauryl (meth) acrylate and the like, and the ethylenically unsaturated monomer may be the total amount of the monomers Based on the total weight of the composition, and may be contained in an amount of 11 wt% to 12 wt%. When the content of the ethylenically unsaturated monomer is less than 10% by weight, the appearance is deteriorated due to its influence on the gloss. When the content of the ethylenically unsaturated monomer is more than 12% by weight, long-

The non-functional acrylic monomer is not particularly limited as long as it does not adversely affect the acrylic polyol resin, but is preferably selected from the group consisting of alkyl (meth) acrylate, cycloalkyl (meth) acrylate and bicycloalkyl (meth) It can be more than one. Examples of the non-functional acrylic monomer include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate Acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, 2-ethylhexyl acrylate, n-butyl acrylate, Octyl acrylate, isobornyl acrylate, cyclohexyl acrylate, and the like, but not limited thereto. The non-functional acrylic monomer may be contained in an amount of 55 wt% to 62 wt% based on the total amount of the monomers used to produce the acrylic resin, and may be included in an amount of 59 wt% to 62 wt%. When the content of the non-functional acrylic monomer is less than 55% by weight, the weatherability of the acrylic monomer may be decreased due to the increase of the functional acrylic monomer. When the amount of the acrylic monomer is less than 62% by weight, The scratch resistance may be poor.

The monomer containing a carboxyl group may be at least one selected from the group consisting of benzoic acid, cyclohexanecarboxylic acid, 2-ethylhexanoic acid, caproic acid, caprylic acid, capric acid, lauric acid, natural and synthetic fatty acids, acrylic acid, methacrylic acid, , Crotonic acid, phthalic acid, isophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, maleic acid, fumaric acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, Acid, sebacic acid, dodecanedioic acid, and the like may be used, but the present invention is not limited thereto. The carboxyl group-containing monomer may be contained in an amount of 4 wt% to 7 wt% based on the total amount of the monomers used for preparing the acrylic resin, and may be included in an amount of 5 wt% to 6.2 wt%. When the content of the carboxyl group-containing monomer is less than 4% by weight, the viscosity is low and scratch resistance is problematic. When the content of the carboxyl group-containing monomer is 7% by weight or more, hydrogen bond between acrylic resin or acrylic resin increases and viscosity increases.

The hydroxyl group-containing monomer may be at least one selected from the group consisting of 2-hydroxyethyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, Acrylate, caprylic methacrylate, caprolactone acrylate, caprolactone methacrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, 4-hydroxymethylcyclohexyl-methyl Acrylate, and the like, but is not limited thereto. The hydroxyl group-containing monomer may be contained in an amount of 15 to 22% by weight, and 18 to 22% by weight based on the total amount of the monomers used for preparing the acrylic resin. When the content of the hydroxyl group-containing monomer is less than 15% by weight, the crosslinking density of the coating film is lowered to lower the physical properties of the coating film. When the content exceeds 22% by weight, the crosslinking density is increased to improve physical properties of the coating film, There is a problem that the spreadability is lowered and the compatibility with other compositions is deteriorated and the appearance of the coating film becomes poor.

An organic solvent or an initiator may further be used for the production of the acrylic resin.

Examples of the organic solvent include, but are not limited to, hydrocarbon solvents such as toluene, xylene, and xylene; ketone solvents such as methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, and ethyl propyl ketone; , Ester solvents such as ethyl acetate, n-propyl acetate, n-butyl acetate and ethyl ethoxypropionate, alcohol solvents such as n-butanol, propanol, butyl alcohol and 1-methoxy- .

The initiator may be a radical polymerization initiator, and the kind of the initiator is not particularly limited, and examples thereof include 2,2'-azobis (2-methylbutylonitrile), 2,2'-azobisisobutyl Ethylhexanoate, tertiary butyl peroxyacetate, tertiary amyl peroxy-2-ethylhexyl peroxy-2-ethylhexyl peroxide, Hexanoate, di-tertiary amyl peroxide, cumyl hydroperoxide, dicumyl peroxide, and the like. The initiator may be contained in an amount of 1 wt% to 7 wt% based on the total amount of the monomers used to produce the acrylic resin, and may be included in an amount of 5 wt% to 7 wt% and 6 wt% to 7 wt% . When the content of the initiator is less than 1% by weight, the degree of polymerization may be low and the physical properties may be deteriorated. If the content of the initiator is more than 7% by weight, the appearance of the coating film may become poor due to over-

The glycidyl ester has a chemical structure represented by the following formula (1).

[Chemical Formula 1]

(Wherein R is an alkyl group having 1 to 30 carbon atoms).

의 구조로 표시될 수 있고, 상기 R¹ 및 R²는 각각 독립적으로 탄소수 1 내지 10의 알킬기이다. 상기 도트(

)는 치환기가 주쇄에 결합하는 위치를 의미한다.Wherein R is

And R ¹ and R ² are each independently an alkyl group having 1 to 10 carbon atoms. The dot (

) Means a position at which a substituent is bonded to a main chain.

The alkyl group may be linear or branched and is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert- butyl, sec- N-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl- Methylhexyl, cyclopentylmethyl, cyclohexylmethyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, 1,1-dimethylpropyl, isohexyl, 4-methylhexyl, 5-methylhexyl and the like, but is not limited thereto.

The glycidyl ester may be contained in an amount of 6 wt% to 12 wt% based on the total amount of the monomers used to produce the acrylic resin, and may be included in an amount of 10 wt% to 12 wt%. When the content of the glycidyl ester is less than 6% by weight, reaction with the acrylic resin may be insufficient, which may cause problems in the scratch resistance and weatherability of the coating material. If the glycidyl ester content is more than 12% by weight, A problem may arise in the appearance of the battery.

The glycidyl ester may react with the acrylic resin having a carboxyl group and a hydroxyl group to cause a ring opening polymerization reaction of the epoxy group of glycidyl. As a result, the modified acrylic polyol resin in which the carboxyl group of the acrylic resin is modified with glycidyl ester is used as the auxiliary resin in the clear coating composition of the present invention, whereby the storage stability of the coating is ensured and the glass transition temperature (T _g ) By improving the flowability and leveling, the appearance of the clear paint can be improved. In addition, by introducing a long chain polyol into the acrylic resin, low-temperature curing becomes possible, thereby improving the appearance of the oil-based clear paint.

The weight average molecular weight of the modified acrylic polyol resin may be 5,000 g / mol to 15,000 g / mol, but is not limited thereto.

The modified acrylic polyol resin is contained in an amount of 10 wt% to 25 wt% based on the total weight of the clear coating composition.

If the content of the modified acrylic polyol resin is less than 10% by weight, the effect of improving the appearance of the paint is not exhibited. If it exceeds 25% by weight, the flowability and leveling of the paint are poor.

The modified acrylic polyol resins may be less than or equal to the glass transition temperature (T _g) that is less than or equal to 0 ℃, more than -10 ℃ 0 ℃ or less, more than -5 ℃ 0 ℃. When the glass transition temperature of the modified acrylic polyol resin satisfies the above range, flowability and leveling of the coating composition are improved.

The modified acrylic polyol resin may have a hydroxyl value of 100 mgKOH / g to 150 mgKOH / g and may have a hydroxyl value of 100 mgKOH / g to 120 mgKOH / g. When the hydroxyl value of the modified acrylic polyol resin is less than 100 mgKOH / g, adherence is poor and weather resistance is adversely affected, and when the hydroxyl value is more than 150 mgKOH / g, the appearance of the modified acrylic polyol resin is deteriorated .

The modified acrylic polyol resin has an acid value of 10 mgKOH / g to 15 mgKOH / g. If the acid value of the modified acrylic polyol resin is less than 10 mgKOH / g, the adhesion of the paint deteriorates, and if the acid value exceeds 15 mgKOH / g, the appearance of the paint deteriorates.

The modified acrylic polyol resin has a viscosity of 70 cP to 110 cP. When the viscosity of the modified acrylic polyol resin satisfies the above range, flow properties and leveling of the prepared clear coating composition are enhanced, and excellent appearance of the coated film can be obtained. When the viscosity of the modified acrylic polyol resin is less than 70 cp, scratch resistance, gloss and weatherability of the paint become poor. When the viscosity exceeds 110 cp, the chipping resistance becomes poor.

<Polyester Polyol Resin>

The clear paint composition of the present invention may further comprise a polyester polyol resin.

When the polyester polyol resin is mixed with an acrylic polyol resin, it is possible to improve the flexibility of the coating film and the paint adhesion, and the gloss and appearance The quality can be improved.

The polyester polyol resin may be one prepared by condensation reaction of an acid monomer and an alcohol monomer. For example, it can be produced by dehydration condensation reaction of dibasic acid (adipic acid) with glycol (Glycol) or triol, and the property and physical properties of the polyester polyol are determined by the acid , Kind of polyol, and molecular weight.

The polyester polyol resin may be contained in an amount of 1 wt% to 10 wt% based on the total weight of the clear paint composition, and may be contained in an amount of 1 wt% to 5 wt%.

The polyester polyol resin has a resin solid content of 60 to 80% by weight, a viscosity of 1,500 to 3,500 cP, an acid value of 20 to 25 mgKOH / g, a hydroxyl value of 130 to 150 mgKOH / g, a glass transition temperature of 0 ° C to 10 ° C, and a weight average molecular weight of 3,000 g / mol to 8,000 g / mol. When the physical properties of the polyester polyol resin satisfy the above ranges, the flexibility of the coating film and the paint adhesion can be improved, and the gloss and appearance quality of the coating film can be improved.

<Curing agent>

The clear coating composition of the present invention comprises a curing agent.

The curing agent used in the present invention can be used without limitation as long as it can cure the hydroxy group of the acrylic polyol resin or the modified acrylic polyol resin.

The curing agent may be at least one selected from a melamine compound and a urethane compound.

The kind of the melamine compound is not particularly limited, but may be, for example, hexamethylol melamine, hexamethoxymethyl melamine, hexabutoxymethyl melamine, and the like.

Wherein the melamine compound has a solids content of 56 to 60 wt%, a viscosity of 600 mPas to 1,000 mPas, a hue of 50 Hazen or less, an acid value of 1 mgKOH / g or less, a weight average molecular weight of 1,000 g / mol to 4,000 g / mol.

The urethane compound can be used without limitation as long as it can be used for a clear paint, and can be produced by reacting an alcohol with a polyisocyanate.

The alcohol may be at least one selected from the group consisting of ethylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, 1,5-pentanediol, 1,2-butanediol, 1,2-hexanediol, bisphenol A, bisphenol F, A, benzene diol, and the like, but is not limited thereto.

The polyisocyanate may be an aliphatic or aromatic isocyanate, and may be an aliphatic polyisocyanate selected from the group consisting of tetramethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate and isophorone diisocyanate; 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, p-phenylene isocyanate, diphenylmethane-4,4'-diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane- &Quot;-triisocyanate; &lt; / RTI &gt; Or a mixture thereof.

The solid content of the urethane compound is 73 wt% to 77 wt%, the viscosity is 2,800 mPas to 5,800 mPas, and the hue can be 100 hazen or less.

The curing agent may be included in an amount of 20% by weight to 50% by weight based on the total weight of the clear coating composition. If the content of the curing agent portion is less than 20% by weight, the physical properties such as hardness and solvent resistance may be affected by incomplete curing when reacted with the main resin. If the content is more than 50% by weight, Etc., and the unreacted curing agent may remain in the coating material, which may adversely affect other physical properties.

<Organic solvents>

The clear coating composition of the present invention may contain an organic solvent.

The organic solvent is not particularly limited as long as it does not pose a problem in the polymerization reaction of the acrylic polyol resin. Examples thereof include aromatic hydrocarbon solvents such as toluene, xylene and xylene, dimethyl ketone, methyl ethyl ketone, methyl propyl ketone, Ketone solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, methyl cellosolve acetate, cellosolve acetate, butyl cellosolve acetate, methyl ethyl ketone, methyl isobutyl ketone, , Ester solvents such as carbitol acetate, and alcohol solvents such as n-propanol, isopropanol, n-butanol, isobutanol, tertiary butanol and the like.

The organic solvent may be contained in an amount of 5% by weight to 20% by weight based on the total weight of the clear coating composition. If the content of the organic solvent is less than 5% by weight, it may be difficult to produce the coating material. If the content is more than 20% by weight, the coating workability may be deteriorated.

<Additives>

The clear coating composition of the present invention may further comprise additives.

The additive may include at least one member selected from the group consisting of a surface conditioner, a light stabilizer, a weathering additive, a drying agent, an appearance control agent, a defoaming agent, and an ultraviolet absorber. The additive may be included in an amount of 0.1 wt% to 5 wt% based on the total weight of the clear paint composition.

Hereinafter, the present invention will be described more specifically by way of examples. However, these examples are provided only for the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

<Synthesis Example>

Preparation Example 1 Preparation of acrylic polyol auxiliary resin A

239 g of xylene and 90 g of butyl alcohol were charged into a four-necked flask for synthesis equipped with a stirrer, a thermometer and a stirrer to raise the temperature to the reflux temperature. Then, 64 g of styrene monomer, 100 g of butyl methacrylate, 123 g of hydroxyethacrylate, , And a mixture of 35 g of methacrylic acid and 36 g of t-butylperoxyacetate was uniformly added over 5 hours. After completion of the dropwise addition, the mixture was maintained at the reflux temperature for 2 hours. When there was no change in viscosity, the mixture was cooled to 120 ° C and 65 g of Cardura E10p glycidyl ester was added dropwise for 2 hours. %, A viscosity CD (Gardner-Holdt), and an acid value of 13 mgKOH / g.

&Lt; Preparation Example 2 > Preparation of acrylic polyol auxiliary resin B

239 g of xylene and 90 g of butyl alcohol were charged into a four-necked flask for synthesis equipped with a stirrer, a thermometer and a stirrer, and the mixture was heated to reflux temperature. Then, 64 g of styrene monomer, 135 g of butyl methacrylate, 83 g of hydroxyethacrylate, , And a mixture of 35 g of methacrylic acid and 36 g of t-butylperoxyacetate was uniformly added over 5 hours. After completion of the dropwise addition, the mixture was maintained at the reflux temperature for 2 hours. When there was no change in viscosity, the mixture was cooled to 120 ° C and 65 g of Cardura E10p glycidyl ester was added dropwise for 2 hours. %, Viscosity A- (Gardner-Holdt) and acid value 13 mg KOH / g.

Preparation Example 3 Preparation of acrylic polyol auxiliary resin C

239 g of xylene and 90 g of butyl alcohol were charged into a four-necked flask for synthesis equipped with a stirrer, a thermometer and a stirrer, and the mixture was heated to reflux temperature. Then, 64 g of styrene monomer, 253 g of butyl methacrylate, 97 g of hydroxyethacrylate, , And a mixture of 35 g of methacrylic acid and 36 g of t-butylperoxyacetate was uniformly added over 5 hours. After completion of the dropwise addition, the mixture was maintained at the reflux temperature for 2 hours. When there was no change in viscosity, the mixture was cooled to 120 ° C and 65 g of Cardura E10p glycidyl ester was added dropwise for 2 hours. %, A viscosity GH (Gardner-Holdt), and an acid value of 13 mgKOH / g.

Production Example 4 Acrylic polyol auxiliary resin D

243 g of xylene and 91 g of butyl alcohol were charged into a four-necked flask for synthesis equipped with a stirrer, a thermometer and a stirrer, and the mixture was heated to reflux temperature. Then, 65 g of styrene monomer, 101 g of butyl methacrylate, 125 g of hydroxyethacrylate, , A mixture of 36 g of methacrylic acid and 18 g of t-butylperoxyacetate was uniformly added over 5 hours. After completion of the dropwise addition, the mixture was maintained at a reflux temperature for 2 hours. When there was no change in viscosity, the mixture was cooled to 120 ° C, and 66 g of Cardura E10p glycidyl ester was added dropwise for 2 hours and reacted until no change in acid value. %, A viscosity R (Gardner-Holdt), and an acid value of 13 mgKOH / g.

&Lt; Preparation Example 5 > Acrylic polyol auxiliary resin E

239 g of xylene and 90 g of butyl alcohol were charged into a four-necked flask for synthesis equipped with a stirrer, a thermometer and a stirrer to raise the temperature to the reflux temperature. Then, 64 g of styrene monomer, 131 g of butyl methacrylate, 138 g of hydroxyethacrylate, , A mixture of 24 g of methacrylic acid and 36 g of t-butylperoxyacetate was uniformly added over 5 hours. After completion of the dropwise addition, the mixture was maintained at the reflux temperature for 2 hours. When there was no change in viscosity, 32 g of Cardura E10p glycidyl ester was added dropwise to the mixture at 120 ° C for 2 hours and then allowed to react until no change in acid value. %, A viscosity F (Gardner-Holdt), and an acid value of 13 mgKOH / g.

&Lt; Preparation Example 6 > Preparation of acrylic polyol auxiliary resin F

239 g of xylene and 90 g of butyl alcohol were charged into a four-necked flask for synthesis equipped with a stirrer, a thermometer and a stirrer, and the mixture was heated to reflux temperature. Then, 64 g of styrene monomer, 164 g of butyl methacrylate, 152 g of hydroxyethacrylate, , A mixture of 13 g of methacrylic acid and 36 g of t-butylperoxyacetate was uniformly added over 5 hours. After completion of the dropwise addition, the mixture was maintained at the reflux temperature for 2 hours and then cooled when there was no change in viscosity to obtain an acrylic polyol auxiliary resin F having a solid content of 50% by weight, a viscosity H-I (Gardner-Holdt) and an acid value of 13 mgKOH / g.

Properties of the acrylic polyol auxiliary resins of Preparation Examples 1 to 6 are shown in Table 1 below.

Item Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Production Example 6 The glass transition temperature (Tg)
(° C) -5 -5 15 -5 -5 -5 Hydroxyl group
(mgKOH / g) 116 86 116 116 116 116 CE10P content
(weight%) 10 10 10 10 5 0 Acid value
(mgKOH / g) 13 13 13 13 13 13 Solids content
(weight%) 50 50 50 50 50 50 Viscosity
(Gardner-Holdt) CD A- G-H R F H-I

&Lt; Examples 1-3 >

And the mixture was stirred at 1,500 rpm for 20 minutes or longer to prepare a clear coating composition.

&Lt; Comparative Examples 1 to 8 &

And the mixture was stirred at 1,500 rpm for 20 minutes or longer to prepare a clear coating composition.

Preparation of Clear Coating Composition (Content:% by weight) ingredient Example Comparative Example One 2 3 One 2 3 4 5 6 7 8 Acrylic polyol resin A 30 30 30 30 30 30 30 30 30 30 0 Acrylic polyol resin B 2 2 2 2 2 2 2 2 2 2 0 Polyester polyol resin A 5 5 5 5 5 5 5 5 5 5 5 Modified acrylic polyol auxiliary resin A 15 10 25 5 30 62 Modified acrylic polyol auxiliary resin B 15 Modified acrylic polyol auxiliary resin C 15 Modified acrylic polyol auxiliary resin D 15 Modified acrylic polyol auxiliary resin E 15 Acrylic polyol auxiliary resin F 15 Melamine 27 27 27 27 27 27 27 27 27 27 27 urethane 3 3 3 3 3 3 3 3 3 3 3 Xylene 15 20 5 15 15 15 15 15 25 0 0 additive 3 3 3 3 3 3 3 3 3 3 3 Sum 100 100 100 100 100 100 100 100 100 100 100

1) Acrylic polyol resin A (main resin) (KCC)

A glass transition temperature of 12 占 폚, a hydroxyl value of 140 mgKOH / g, a weight average molecular weight of 15,000 g / mol, and a weight average molecular weight of 15,000 g / mol.

2) Acrylic polyol resin B (auxiliary resin: leveling agent) (KCC)

Solid: 50% by weight, Gardner-Holdt: A2 to A, glass transition temperature: 15 占 폚, weight average molecular weight: 6,000 g / mol

3) Polyester polyol resin A (auxiliary resin) (KCC)

A glass transition temperature of 5 占 폚, a hydroxyl value of 135 mgKOH / g, a weight average molecular weight of 5,000 g / mol, and a glass transition temperature of 5,000 占 폚.

4) Melamine (hardener) (Luperox012, BASF)

Solids content: 56 wt% to 60 wt%, viscosity: 600 mPas to 1,000 mPas, color: 50 hazen or less, acid value: 1 mgKOH / g or less, weight average molecular weight: 1,000 g / mol to 4,000 g / mol,

5) Urethane (Desizing agent) (Desmodur PL350, Covestro AG)

Solid content: 73 wt% to 77 wt%, viscosity: 2,800 mPas to 5,800 mPas, color: less than 100 hazen, appearance: clear

6) Additive (Tinuvin 5151, BASF)

Transmittance: 85% or more, Appearance: clear

<Experimental Example>

The clear paint compositions of Example 1 and Comparative Examples 1 to 8 prepared by mixing the compositions of Table 2 were subjected to the following conditions, and the physical properties of the coating compositions were measured.

<Coating condition>

 Handgun Spray

 Nozzle diameter: 1.5 mm, air pressure: 4.5 kgf / ㎠

 Keeping the distance between nozzle inlet and specimen constant in the range of 2-30 cm, moving horizontally at a constant speed of 40-50 cm / sec.

 After coating, the physical properties of the coating film (image quality, scratch resistance, gloss, hardness, weatherability, resistance to chipping) were measured after baking at 130 ° C for 20 minutes.

<Evaluation method>

1) The image clarity (DOI, Distinctness of Image) was used to measure the appearance of the top coated paint in accordance with MS653-01- SPEC with WAVESCAN DUAL instrument. (CF)

2) The scratches were evaluated by CAR WASHER method according to MS653-01 SPEC as a method of showing the degree of gloss retention in the coating film damaged by the car washes.

3) Gloss indicates the gloss quality level of the coating and evaluated by KCC-7-28-0022 method according to MS653-01 SPEC.

(KCC-7-28-0022: After the dry specimen is completely cooled, measure / record the 20 ° gloss value at 30 μm / 40 μm / 50 μm for each clear film using a specified Polish (BYK Gardner-micro gloss) .)

4) The hardness was evaluated by the KCC-7-28-3000 method according to MS653-01 SPEC as a measure of hardness of the coating.

(KCC-7-28-3000:

A) Use a SANDPAPER to level the end of the pencil lead.

B) Hold the pencil so that the tip of the pencil lead is at an angle of 45 ° to the specimen.

(C) Five times, one time per pencil type, with appropriate force on the surface of the specimen prepared according to the prescribed conditions

D) At this time, the pressing force of the pencil on the specimen should be about 500 g / ㎠.

Note 1) When erasing a test area with an eraser, erase it perpendicular to the test direction to reduce the error caused by scratching.

Note 2) The thickness, temperature and humidity of the test specimens have a considerable effect on the hardness, so they are tested under standard conditions.

Note 3) The strength of the pencil is H> F> HB> B> 2B.

How to judge: Erase the test area with an eraser and record the number of pencil marks that do not appear more than once.)

5) The weatherability was evaluated as KCC-7-28-3403 method according to MS-653-01 SPEC.

(KCC-7-28-3403 Method:

<WOM device condition>

Light quantity: 0.35 ± 0.01 W / m 2 Quantity of light at 340 nm

Specimen temperature: 63 ° C ± 1 ° C, Humidity -50% ± 5%

Spray: 102min Light After 18min Light & Spray

<Measurement method>

A) Insert 6cm X 15cm Test Sample (Specimen, Base, etc.) into the Holder and attach it to the Rack.

B) Press the Equalizing Cycle button to worm up the equipment for about 5 minutes.

Press the Operate button and then the Lamp Ignition button to start the machine.

D) Perform the test according to 3,600 hours.

Note 1) Weatherability means good adhesion in the order of M-1.0> M-1.5> M-2.0> M-2.5> M-3.0.

6) The chipping resistance was evaluated by the method of MS653-01 SPEC to evaluate the resistance to chipping caused by the stone of the film.

division Example Comparative Example One 2 3 One 2 3 4 5 6 7 8 Image sharpness 59CF 59CF 59CF 55CF 54CF 55CF 57CF 50CF 55CF 59CF 45CF My scratch 72% 70% 70% 61% 63% 63% 63% 60% 60% 60% 55% Polish 95% 92% 93% 84% 83% 85% 85% 82% 82% 82% 77% Hardness H HB HB HB B HB HB HB HB 2B 4B Weatherability M-1.0 M-1.0 M-1.0 M-2.0 M-1.5 M-1.5 M-2.0 M-3.0 M-1.5 M-1.5 M-3.0 Chipping resistance 2.5 grade 2.5 grade 2.5 grade 2.5 grade Class 3 Class 3 2.5 grade Class 3 Class 3 Class 3 Class 3

As shown in Table 3, in the case of coating using the clear coating composition prepared in Examples 1 to 3, the hardness and the chipping resistance were comparable to those of the coating using the clear coating composition prepared in Comparative Examples 1 to 8 , Image clarity, scratch resistance, gloss, weather resistance, and chipping resistance.

Particularly, in the case of coating using the clear paint composition prepared in Examples 1 to 3, particularly excellent physical properties in view of image clarity, scratch resistance and gloss were obtained compared with coatings using the clear paint composition prepared in Comparative Examples 1 to 5 .

In the case of coating using the clear coating composition prepared in Examples 1 to 3, the modified acrylic polyol resin was contained in an amount of less than 10% by weight as in Comparative Example 6, or the modified acrylic polyol resin was contained in an amount of less than 25% The scratch resistance, the gloss, and the weather resistance, as compared with the coating using the clear coating composition containing the excess amount of the clear coating composition.

Further, in the case of coating using a clear paint composition containing a modified acrylic polyol resin as an auxiliary resin as in Examples 1 to 3, a paint using a clear paint composition using a modified acrylic polyol resin alone as a main resin as in Comparative Example 8 , It was confirmed that it has excellent physical properties in terms of image clarity, scratch resistance, gloss and weather resistance.

Accordingly, the paint using the one-pack clear coating composition containing the modified acrylic polyol resin of the present invention has excellent image clarity, scratch resistance, gloss and weatherability.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (9)

One or more acrylic polyol resins,
A modified acrylic polyol resin produced by the reaction of an acrylic resin having a carboxyl group and a hydroxyl group with glycidyl ester and
1. A one-part clear coating composition comprising a curing agent,
Wherein the modified acrylic polyol resin is contained in an amount of 10% to 25% by weight based on the total weight of the clear paint composition, and the viscosity is 70 cP to 110 cP. The method according to claim 1,
Wherein the glycidyl ester has a chemical structure represented by the following formula (1).
[Chemical Formula 1]

(Wherein R is an alkyl group having 1 to 30 carbon atoms). The method according to claim 1,
Wherein said modified acrylic polyol resin has a glass transition temperature (Tg) of 0 占 폚 or less, a hydroxyl value of 100 mgKOH / g to 150 mgKOH / g and an acid value of 10 mgKOH / g to 15 mgKOH / g . The method according to claim 1,
Based on the total weight of the clear paint composition
Wherein the one or more acrylic polyol resins are contained in an amount of 30 wt% to 70 wt%
Wherein the curing agent is contained in an amount of 20 wt% to 50 wt%. The method according to claim 1,
Wherein the at least one acrylic polyol resin has a glass transition temperature of from 10 캜 to 50 캜. The method according to claim 1,
Wherein the at least one acrylic polyol resin comprises a first acrylic polyol resin and a second acrylic polyol resin. The method of claim 6,
Wherein the first acrylic polyol resin is contained in an amount of 20 wt% to 69.9 wt% based on the total weight of the clear coating composition,
Wherein the second acrylic polyol resin is contained in an amount of 0.1% by weight to 30% by weight based on the total weight of the clear coating composition. The method of claim 6,
Wherein the first acrylic polyol resin has a resin solid content of 55 wt% to 70 wt%, a viscosity of 950 cP to 2,400 cP, an acid value of 5 mgKOH / g to 15 mgKOH / g, a hydroxyl value of 120 mgKOH / g to 170 mgKOH / g, a glass transition temperature of 10 占 폚 to 20 占 폚, and a weight average molecular weight of 10,000 g / mol to 30,000 g / mol. The method of claim 6,
Wherein the second acrylic polyol resin has a resin solid content of 40 wt% to 60 wt%, a viscosity of 20 cP to 55 cP, a glass transition temperature of 10 캜 to 50 캜, a weight average molecular weight of 3,000 g / mol to 15,000 g / mol. &lt; / RTI &gt;