KR20190103632A - Coating composition - Google Patents

Abstract

The present invention relates to a paint composition comprising an acrylic resin obtained from an acrylic resin composition comprising an aromatic vinyl-based monomer, a hydrophobic (meth)acrylate monomer containing a bulky functional group, and a crosslinkable (meth)acrylate monomer. The paint composition can form a paint film which exhibits excellent adhesion to various materials and has excellent corrosion resistance, waterproof properties, moisture resistance, weather-proof properties, and durability.

Description

Coating composition {COATING COMPOSITION}

The present invention relates to a coating composition capable of forming a coating film excellent in corrosion resistance, water resistance, weather resistance, moisture resistance, adhesion, durability, and the like.

Since construction machinery and heavy equipment such as bulldozers, excavators and wheel loaders are made of a metal material, the surface is easily corroded by snow, rain, salt, etc., and the life thereof is reduced. Thus, the surfaces of construction machinery and heavy equipment are painted with a paint composition to prevent surface corrosion and scratching. The coating composition requires various physical properties such as corrosion resistance, acid resistance, alkali resistance and weather resistance.

Korean Patent No. 10-0682369 discloses a thermosetting two-component epoxy coating composition using bisphenol A epoxy resin, phenol novolac epoxy resin, and cresol novolac epoxy resin as a subject. However, the two-component epoxy coating composition only satisfies the evaluation criteria with a blister size of 0.5 mm or less in the corrosion resistance evaluation after 1,000 hours only when coated with a thick film thickness of 100 μm or more, and the coating film thickness is 30 μm or less. If thin, the above-mentioned corrosion resistance evaluation criteria are not satisfied.

The present invention provides a coating composition capable of forming a coating film excellent in corrosion resistance, water resistance, moisture resistance, weather resistance, durability and adhesion.

The present invention provides an acrylic resin composition comprising an aromatic vinyl monomer, a hydrophobic (meth) acrylate monomer containing a bulky functional group, and a crosslinkable (meth) acrylate monomer.

Moreover, this invention provides the coating composition containing the main part containing the acrylic resin obtained from the said acrylic resin composition, and the hardening | curing agent part containing an isocyanate.

The coating composition of the present invention is not only excellent in adhesion to various materials such as ferrous materials, nonferrous materials, and glass, but also can form a coating film excellent in corrosion resistance, water resistance, moisture resistance, weather resistance and durability.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail. However, the present invention is not limited only to the following contents, and each component may be variously modified or optionally mixed as necessary. Therefore, it is to be understood that all changes, equivalents, and substitutes included in the spirit and scope of the present invention are included.

In this specification, "(meth) acrylate" represents an acrylate or a methacrylate.

The coating composition according to the present invention is a two-component coating composition comprising a main portion containing an acrylic resin and a curing agent portion containing an isocyanate, wherein the acrylic resin contains three different repeating units different from each other. As a result, the present invention can form a coating film having excellent adhesion to various materials such as steel, nonferrous metals, glass, etc., and also having excellent corrosion resistance, water resistance, moisture resistance, durability, and adhesion. It can also be applied to the painting of automotive parts (especially exterior parts).

Hereinafter, the composition of the coating composition will be described.

<Topic>

In the coating composition according to the present invention, the main portion contains an acrylic resin, and may further include a pigment and a solvent as necessary.

Acrylic resin

In the present invention, the acrylic resin is a polymer obtained from an acrylic resin composition comprising an aromatic vinyl monomer, a hydrophobic (meth) acrylate monomer containing a bulky functional group, and a crosslinkable (meth) acrylate monomer. The acrylic resin has a first repeating unit derived from an aromatic vinyl monomer, a second repeating unit derived from a hydrophobic (meth) acrylate monomer containing a bulky functional group, and a third derived from a crosslinkable (meth) acrylate monomer. It is a copolymer containing a repeating unit.

Aromatic Vinyl  Monomer

The aromatic vinyl monomer in the acrylic resin composition imparts corrosion resistance and impact resistance to the resin.

The aromatic vinyl monomer usable in the present invention is a C ₆ to C ₄₀ aromatic hydrocarbon compound containing a vinyl group, such as styrene, α-methylstyrene, α-ethylstyrene, β-methylstyrene, p-methylstyrene, pt Styrene compounds such as butyl styrene, ethyl styrene, vinyl xylene, monochloro styrene, dichloro styrene, dibromostyrene and the like; Vinyl naphthalene compounds such as vinyl naphthalene, dibromo vinyl naphthalene, and the like, but are not limited thereto. These may be used alone or in combination of two or more thereof.

For example, the first repeating unit derived from the aromatic vinyl monomer may be a repeating unit represented by Formula 1 below.

[Formula 1]

In Chemical Formula 1,

R ₁ is a C ₆ to C ₄₀ aryl group which is unsubstituted or substituted with one or more substituents selected from the group consisting of halogen and C ₁ to C ₁₂ alkyl groups.

Non-limiting examples of the repeating unit represented by Formula 1 include a repeating unit represented by the following Formula 1a.

[Formula 1a]

In Chemical Formula 1a,

Z ₁ is the same as or different from each other, and is each independently selected from the group consisting of halogen and C ₁ to C ₁₂ alkyl groups.

The content of the aromatic vinyl monomer may be 30 to 55% by weight based on the total amount of monomers in the acrylic resin composition. When the content of the aromatic vinyl monomer is less than 30% by weight, corrosion resistance and impact resistance may be poor, and when the content of the aromatic vinyl monomer exceeds 55% by weight, the wetting (wetting) of the paint may be deteriorated and the appearance may be poor.

Bulky  Hydrophobic containing functional groups ( Meta ) Acrylate  Monomer

The hydrophobic (meth) acrylate monomer containing a bulky functional group in the acrylic resin composition can increase the glass transition temperature of the acrylic resin, thereby improving corrosion resistance. Moreover, hydrophobicity can be provided to an acrylic resin and water resistance of a coating film can be provided.

Examples of hydrophobic (meth) acrylate monomers containing bulky functional groups usable in the present invention include C ₅ to C ₂₀ alkyl (meth) acrylates, C ₅ to C ₄₀ alicyclic (meth) acrylates, and the like. There is no limitation. Non-limiting examples of the C ₅ to C ₂₀ alkyl (meth) acrylates include ethylhexyl (meth) acrylate, nonyl (meth) acrylate, n-octyl (meth) acrylate, and decyl (meth) acrylate. , Tetradecyl (meth) acrylate, and the like, and non-limiting examples of the C ₅ to C ₄₀ alicyclic (meth) acrylates include isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like. have. These may be used alone or in combination of two or more thereof.

For example, the second repeating unit derived from the hydrophobic (meth) acrylate monomer containing the bulky functional group may be a repeating unit represented by the following Chemical Formula 2.

[Formula 2]

In Chemical Formula 2,

R ₂ is hydrogen or a methyl group,

R ₃ is a C ₅ to C ₂₀ alkyl group or C ₅ to C ₄₀ alicyclic ring group which is unsubstituted or substituted with one or more substituents selected from the group consisting of halogen and C ₁ to C ₁₂ alkyl groups.

Specific examples of the repeating unit represented by Formula 2 include a repeating unit represented by the following Formula 2a, but are not limited thereto.

[Formula 2a]

In Chemical Formula 2a,

R ₂ is hydrogen or a methyl group,

Z ₂ are the same as or different from each other, and are each independently selected from the group consisting of halogen and C ₁ to C ₁₂ alkyl groups.

The content of the hydrophobic (meth) acrylate monomer containing the bulky functional group may be 5 to 40% by weight based on the total amount of monomers in the acrylic resin composition. If the content of the hydrophobic (meth) acrylate monomer containing the bulky functional group is less than 5% by weight, the corrosion resistance and impact resistance may be poor, and when the content of the hydrophobic (meth) acrylate monomer is greater than 40% by weight, the wettability of the paint may be reduced. This can be bad.

Crosslinkable  ( Meta ) Acrylate  Monomer

In the acrylic resin composition, the crosslinkable (meth) acrylate monomer may improve the hardness of the resin by increasing the degree of crosslinking of the acrylic resin, thereby increasing mechanical strength and chemical stability.

Non-limiting examples of the crosslinkable (meth) acrylate monomers that can be used in the present invention include bifunctional or higher functional (meth) acrylates, (meth) acrylates containing double bonds, and mixtures thereof.

The said bifunctional or more (meth) acrylate is a compound which has 2 or more (for example, 2-6 pieces) of (meth) acrylate groups which are unsaturated groups which can superpose | polymerize. For example, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyolefin glycol di (meth) acrylate, ethoxylated polypropylene glycol di (Meth) acrylate, 2-hydroxy-1,3-dimethacryloxypropane, dioxane glycol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, 1,4-butanediol di ( Meta) acrylate, glycerin di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentylglycol di (meth) acrylate, 2 -Methyl-1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, butylethylpropanediol di (meth) acrylate, 3-methyl-1,5-pentanediol Bifunctional (meth) acrylate monomers such as di (meth) acrylate; Trimethylolpropane tri (meth) acrylate, ethoxylated glycerin tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri ( Trifunctional (meth) acrylate monomers such as meta) acrylate; Tetrafunctional (meth) acrylate monomers such as pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, and the like; Dipentaerythritol polyacrylate, and the like, but is not limited thereto. These may be used alone or in combination of two or more thereof.

The (meth) acrylate containing the said double bond is a compound which contains the (meth) acrylate group in a molecule | numerator, and contains 1 or more of double bonds, for example, 2-3. Examples of the (meth) acrylate containing such a double bond include vinyl group-containing (meth) acrylates such as allyl (meth) acrylate, but are not limited thereto.

For example, the third repeating unit derived from the crosslinkable (meth) acrylate monomer may be a repeating unit represented by the following Formula 3.

[Formula 3]

In Chemical Formula 3,

R ₄ and R ₅ are the same as or different from each other, and each independently hydrogen or a methyl group,

R ₆ is a C ₁ to C ₂₀ alkylene group unsubstituted or substituted with one or more substituents selected from the group consisting of halogen and C ₁ to C ₁₂ alkyl groups.

The content of the crosslinkable (meth) acrylate monomer may be 0.05 to 10% by weight based on the total amount of monomers in the acrylic resin composition. If the content of the crosslinkable (meth) acrylate monomer is less than 0.05% by weight, there is a problem in that the crosslinking reaction is not initiated. If the content of the crosslinkable (meth) acrylate monomer is more than 10% by weight, the crosslinking degree may be too high, leading to poor gloss.

The acrylic resin composition of this invention may further contain the normal monomer used for an acrylic resin besides the 3 types of monomer mentioned above as needed. For example, it may further include a C ₁ to C ₄ alkyl (meth) acrylic monomer.

Non-limiting examples of C ₁ to C ₄ alkyl (meth) acrylic monomers usable in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl ( Meta) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, and the like.

The content of the other monomers is not particularly limited, and may be, for example, 25 to 65% by weight based on the total amount of monomers in the acrylic resin composition.

The acrylic resin according to the present invention may have a Gardner viscosity of W to Z1 and a weight average molecular weight of 35,000 to 45,000 g / mol. In addition, the glass transition temperature may be 10 to 75 ℃.

The production method of the acrylic resin is not particularly limited as long as it is a polymerization method of conventional acrylic resin known in the art, for example, solution polymerization, emulsion polymerization or suspension polymerization. For example, a solvent (e.g., xylene) is added to the reactor, and the temperature inside the reactor is raised to a predetermined temperature, and then an aromatic vinyl monomer (e.g., styrene) and a hydrophobic (meth) acrylate containing a bulky functional group. An acrylic resin may be prepared by adding a monomer (eg, isobornyl acrylate) and a crosslinkable (meth) acrylate monomer (eg, 1,6-hexanediol diacrylate) and then adding a solvent and a polymerization initiator to react. Can be.

In the undercoat composition according to the present invention, the content of the acrylic resin is not particularly limited, and may be, for example, about 20 to 65% by weight based on the total amount of the main parts. When the content of the acrylic resin is in the above-described range, the workability is excellent, not only the appearance characteristics of the coating film are excellent, but also the hardness of the coating film is increased, thereby providing excellent impact resistance and corrosion resistance.

Pigment

In the coating composition according to the invention, the subject matter may further comprise customary pigments known in the art, if necessary. The pigment is included to express a desired color (colour) in the paint or to increase the strength or gloss of the coating.

As the pigment, organic pigments, inorganic pigments, metallic pigments, aluminum pastes (Al-paste), pearls, sieving pigments, and the like, which are commonly used in the paint field, may be used without limitation. The above can be mixed. Non-limiting examples of the pigment may be a pigment of the red, yellow / orange, blue, black, white, pearl and metallic series.

In the present invention, the content of the pigment is not particularly limited, and may be, for example, about 1 to 10% by weight based on the total amount of the main parts. When the content of the pigment is in the above-described range, the appearance properties and mechanical properties of the coating film may be improved without deteriorating dispersibility and storage stability.

solvent

In the coating composition according to the present invention, the main portion may further include a solvent as necessary. The solvent dissolves the components constituting the main portion to adjust the viscosity and to facilitate the painting work, it is included for the purpose of improving the smoothness and coating workability of the coating film (coating layer) by adjusting the volatilization rate of the solvent.

The solvent usable in the present invention is not particularly limited as long as it is a conventional solvent known in the art. For example, ketone solvents, ester solvents, ether solvents, hydrocarbon solvents, alcohol solvents, or mixtures thereof. Non-limiting examples of the solvent include butyl acetate, propylene glycol methyl ether, toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, ethyl propyl ketone, methyl isobutyl ketone, methyl acetate, ethyl acetate, normal propyl Acetate, isopropyl acetate, methyl cellosolve acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, normal propanol, isopropanol, normal butanol, isobutanol, tert-butanol, benzene, acetone, tetrahydrofuran, dimethyl Formaldehyde, cyclohexanone, methanol, ethanol and the like. These may be used alone or in combination of two or more thereof.

In the present invention, the content of the solvent is not particularly limited, and may be, for example, the remaining amount to adjust the total amount of the main part to 100% by weight, for example, may be 5 to 25% by weight. When the content of the solvent is in the above-described range, workability and appearance characteristics of the coating film may be improved.

additive

In the coating composition according to the invention, the subject matter may optionally further comprise customary additives known in the art, in addition to the components described above as necessary.

In one example, the subject may further comprise one or more additives selected from the group consisting of antifoaming agent, leveling agent, surface conditioner, ultraviolet absorber, ultraviolet stabilizer, desiccant, moisture absorbent and coupling agent.

The content of the additive is not particularly limited, and may be, for example, 0.1 to 15% by weight based on the total amount of the main parts.

<Hardener part>

In the coating composition according to the present invention, the curing agent portion may include isocyanate, and may further include a solvent as necessary.

Isocyanate is resin for hardener which reacts with the acrylic resin of a main part, and advances hardening of a composition. In the present invention, as the resin for the curing agent may be used a conventional aliphatic or aromatic isocyanate compound known in the art. For example, non-yellowing type isocyanate trimers such as hexamethylene diisocyanate trimers can be used.

Non-limiting examples of isocyanate curing agents that can be used include polyisocyanate, hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer (HDT), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), tetramethylxylene diisocyanate, methylenediphenyl diisocyanate (MDI), toluene diisocyanate (TDI), mixtures of two or more thereof, or polymers thereof.

In the present invention, the content of the isocyanate may be about 30 to 60% by weight, for example, about 40 to 60% by weight based on the total amount of the curing agent portion. If the content of the isocyanate is smaller than the above-mentioned range, there may be a problem in hardness, dryness, etc. due to incomplete curing, and if the content is higher than the above-mentioned range, there may be a problem in that the viscosity of the composition becomes high.

As the solvent for the curing agent, a conventional solvent known in the art may be used. The solvent for the curing agent may be the same as or different from the solvent of the above-mentioned main part.

In the present invention, the content of the solvent for the curing agent is not particularly limited, and may be, for example, a residual amount that is adjusted so that the total amount of the curing agent portion is 100% by weight, for example, about 5 to 40% by weight. When the content of the solvent is in the above-described range, workability and appearance characteristics of the coating film may be improved.

In the coating composition according to the invention, the above-mentioned main part and the curing agent part are mixed in a weight ratio of 3 to 9: 1, for example, in a weight ratio of 5.5 to 6.5: 1.

The coating composition of the present invention is not only excellent in adhesion to various materials such as ferrous materials, nonferrous materials, glass, etc., but also can form a coating film (eg, undercoat) having excellent corrosion resistance, water resistance, moisture resistance, weather resistance, and durability. In particular, the coating composition of the present invention has excellent corrosion resistance even if the thickness of the coating film is as thin as about 100 μm or less (eg about 30 ± 5 μm). For example, after 500 hours of X-cutting, the unilateral length (width) of the blister of the X-cutting portion may be about 1 mm or less, for example about 0.5 to 1 mm.

Therefore, the coating composition according to the present invention can be applied to a painting process for construction machinery and heavy equipment, such as a coating process step, to prevent corrosion of heavy equipment. However, it is not limited to this and is applicable to various process steps and uses.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only to aid the understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

[ Production Example  1]-Synthesis of Acrylic Resin 1

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (27 g), n-butyl acrylate (5.4 g), methacrylate (6 g), and butyl. Methaacrylate (0.3 g), isobornyl acrylate (5.4 g), 2-hydroxyethyl acrylate (9.8 g) and 1,6-hexanediol diacrylate (0.05 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 1 (solid content: 52.3%, weight average molecular weight: 40,000 g / mol, viscosity: X, Gardner color: 1 or less), appearance: clear, Glass transition temperature: 50 ° C.).

Production Example 2 Synthesis of Acrylic Resin 2

Xylene (22 g) was added to a four neck flask and the reflux temperature was raised to 144 ° C., followed by styrene monomer (18.9 g), n-butyl acrylate (16.4 g), and methacrylate (1.6 g). , Butyl methacrylate (0.3 g), isobornyl acrylate (6.5 g), 2-hydroxyethyl acrylate (9.8 g) and 1,6-hexanediol diacrylate (5.4 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux temperature for 2 hours and then cooled to obtain acrylic resin 2 (solid content: 53.3%, weight average molecular weight: 42,000 g / mol, viscosity: X-, Gardner color: 1 or less, appearance: Clear) , Glass transition temperature: 21 ° C.) was obtained.

[Comparative Preparation Example 1]-Synthesis of Acrylic Resin 3

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (27 g), n-butyl acrylate (5.6 g), methacrylate (11 g), and butyl. Methaacrylate (0.3 g) and 2-hydroxyethyl acrylate (9.9 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 3 (solid content: 52.7%, weight average molecular weight: 37,000 g / mol, viscosity: W +, Gardner color: 1 or less, appearance: Clear, Glass transition temperature: 50 ° C.).

Comparative Preparation Example 2-Synthesis of Acrylic Resin 4

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (27 g), n-butyl acrylate (5.6 g), methacrylate (11 g), and butyl. Methacrylate (0.3 g), 2-hydroxyethyl acrylate (9.9 g) and 1,6-hexanediol diacrylate (0.05 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 4 (solid content: 52.5%, weight average molecular weight: 40,000 g / mol, viscosity: Y-, Gardner color: 1 or less, appearance: Clear) , Glass transition temperature: 50 ° C.) was obtained.

[ Comparative Production Example  3]-Synthesis of Acrylic Resin 5

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (27 g), n-butyl acrylate (4.8 g), methacrylate (5.1 g), Butyl methacrylate (1.7 g), isobornyl acrylate (5.4 g) and 2-hydroxyethyl acrylate (9.9 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly at the same time for 3 hours to the flask. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 5 (solid content: 52.1%, weight average molecular weight: 40,000 g / mol, viscosity: Y, Gardner color: 1 or less, appearance: Clear, Glass transition temperature: 50 ° C.).

[ Comparative Production Example  4]-Synthesis of Acrylic Resin 6

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (2.7 g), n-butyl acrylate (34 g), methmethyl acrylate (1.9 g), Butyl methacrylate (0.1 g), isobornyl acrylate (5.4 g), 2-hydroxyethyl acrylate (9.9 g) and AMSD (0.05 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 6 (solid content: 51.8%, weight average molecular weight: 42,000 g / mol, viscosity: W, Gardner color: 1 or less, appearance: Clear, Glass transition temperature: 50 ° C.).

[ Comparative Production Example  5]-Synthesis of Acrylic Resin 7

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (32.5 g), n-butyl acrylate (4.2 g), and butyl methacrylate (0.5 g). , Isobornyl acrylate (6.5 g), 2-hydroxyethyl acrylate (9.8 g) and 1,6-hexanediol diacrylate (0.5 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 7 (solid content: 51.8%, weight average molecular weight: 38,000 g / mol, viscosity: Z1, Gardner color: 1 or less, appearance: Clear, Glass transition temperature: 53 ° C.).

[ Comparative Production Example  6]-Synthesis of Acrylic Resin 8

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (18.9 g), n-butyl acrylate (2.5 g), and butyl methacrylate (0.05 g). , Isobornyl acrylate (22.2 g), 2-hydroxyethyl acrylate (9.8 g) and 1,6-hexanediol diacrylate (0.5 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 8 (solid content: 52.1%, weight average molecular weight: 40,000 g / mol, viscosity: Y, Gardner color: 1 or less), appearance: Clear, Glass transition temperature: 59 ° C.).

[ Comparative Production Example  7]-Synthesis of Acrylic Resin 9

Xylene (22 g) was added to a four neck flask, and the reflux temperature was raised to 144 ° C., followed by styrene monomer (18.9 g), n-butyl acrylate (8 g), methacrylate (4.3 g), Butyl methacrylate (0.5 g), isobornyl acrylate (6.5 g), 2-hydroxyethyl acrylate (9.8 g) and 1,6-hexanediol diacrylate (6 g) were added and mixed. Thereafter, xylene (11 g) and di-tert-butylperoxide (0.2 g) were added dropwise and uniformly to the flask simultaneously for 3 hours. After completion of the dropwise addition, the mixture was kept at reflux for 2 hours and then cooled to obtain acrylic resin 9 (solid content: 52.9%, weight average molecular weight: 40,000 g / mol, viscosity: X, Gardner color: 1 or less, appearance: Clear, Glass transition temperature: 36 ° C.).

[ Example  1-2]

According to the use content shown in Table 1, to prepare a main body by mixing acrylic resin, pigments, solvents and additives, to prepare a curing agent by mixing the isocyanate and solvent, and then mixing the main body and the curing agent in a weight ratio of 6: 1 The coating composition of Example 1-2 was prepared. In Table 1, the amount of each component used is in parts by weight.

[Comparative Example 1-7]

According to the use amount shown in Table 1, to the coating composition of Comparative Example 1-7 was prepared in the same manner as in Example 1-2.

Experimental Example

The corrosion resistance of the coating compositions prepared in Examples 1-2 and Comparative Examples 1-7 was evaluated as follows, and the results are shown in Table 2 below.

Each coating composition was spray-coated with the coating film thickness of 30 +/- 5micrometer on the cold rolled steel plate CR (thickness: 0.7T) in which the zinc phosphate film was formed. Thereafter, the mixture was cured in an oven at 80 ° C. for 30 minutes, and then dried at room temperature for 7 days in an RT apparatus. Thereafter, X-cut to the center of the dried specimen was put into a corrosion resistance tester (Q-fog Cyclic corrosion Tester, Q-LAB, U.S.A). The unilateral value of the X-Cut part was measured for specimens which elapsed 240/500 hours under conditions continuously exposed to a spray spray of 5% concentration at 35 ° C. in a Q-fog machine.

The coating composition of Example 1-2 using the acrylic resin according to the present invention exhibited excellent corrosion resistance satisfying the standard of which the unilateral value was 0.5 to 1 mm after 500 hours. On the other hand, the coating composition of Comparative Example 1-7 showed poor corrosion resistance compared to the example coating.

Claims (7)

An acrylic resin composition comprising an aromatic vinyl monomer, a hydrophobic (meth) acrylate monomer containing a bulky functional group, and a crosslinkable (meth) acrylate monomer. The acrylic resin composition of claim 1, wherein the aromatic vinyl monomer is at least one selected from the group consisting of C ₆ to C ₄₀ aromatic hydrocarbon compounds containing a vinyl group. The group of claim 1, wherein the hydrophobic (meth) acrylate monomer containing the bulky functional group is composed of C ₅ to C ₂₀ alkyl (meth) acrylates and C ₅ to C ₄₀ alicyclic (meth) acrylates. Acrylic resin composition which is one or more selected from. The acrylic resin composition according to claim 1, wherein the crosslinkable (meth) acrylate monomer is at least one selected from the group consisting of bifunctional or higher polyfunctional (meth) acrylates and a (meth) acrylate containing a double bond. According to claim 1, 30 to 55% by weight of the aromatic vinyl monomer, based on the total amount of monomers in the acrylic resin composition, 5 to 40% by weight of the hydrophobic (meth) acrylate monomer containing the bulky functional group and the crosslinkability An acrylic resin composition comprising 0.05 to 10% by weight of a (meth) acrylate monomer. Coating composition containing the crosslinking agent containing the main body and the isocyanate containing the acrylic resin obtained from the acrylic resin composition of any one of Claims 1-5. The coating composition of claim 6, wherein the acrylic resin has a Gardner viscosity of W to Z1, a weight average molecular weight of 35,000 to 45,000 g / mol, and a glass transition temperature of 10 to 75 ° C.