KR20210048338A - Coating Composition - Google Patents

Abstract

The present invention relates to a coating composition capable of realizing a high-brightness metallic appearance. The coating composition of the present invention includes: an acrylic-modified polyester resin; a phosphoric acid-modified polyester resin; an acrylic resin; and a nitrocellulose resin. The coating composition according to the present invention can realize a high-brightness metallic appearance and can be used in various high-end finishing materials.

Description

Coating Composition

The present invention relates to a coating composition capable of realizing a high luminance metallic appearance.

PCM (Pre-Coated Metal) paints are used as clear paint compositions for home appliances because they have excellent workability and hardness while securing scratch resistance. Recently, as the interior interior role of home appliances has become important, the demand for home appliances with various patterns, colorful colors and elegant appearance is gradually increasing, and the paint composition used for home appliances is also a direction in which the above properties can be secured. Development is in progress.

In particular, the demand for paints for realizing a high-bright metallic appearance is increasing, but only a paint composition that can apply a spray painting method is being used, and a paint composition that can apply a roll coating method for PCM is It has not been developed yet. Accordingly, there is a continuing demand for a coating composition for PCM that can realize a high-bright metallic appearance while having excellent basic paint properties.

The present invention provides a coating composition capable of realizing a high luminance metallic appearance.

The present invention provides a coating composition comprising an acrylic modified polyester resin, a phosphoric acid modified polyester resin, an acrylic resin, and a nitrocellulose resin.

The coating composition according to the present invention can realize a high-brightness metallic appearance and thus can be used in a variety of high-end finishing products. In addition, the coating composition of the present invention can be applied to a roll coating method for PCM.

Hereinafter, the present invention will be described in detail. However, it is not limited only by the following contents, and each component may be variously modified or selectively used as necessary. Therefore, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

The coating composition according to the present invention includes an acrylic modified polyester resin, a phosphoric acid modified polyester resin, an acrylic resin, and a nitrocellulose resin. In addition, the coating composition according to the present invention may further include a curing resin, a pigment, a curing accelerator, a solvent, and additives commonly used in the art, if necessary. Hereinafter, the composition of the coating composition of the present invention is as follows.

Acrylic modified polyester resin

The coating composition according to the present invention includes an acrylic modified polyester resin. Acrylic-modified polyester resin reacts with a curing agent to form a coating film, gives gloss, and secures high corrosion resistance, processability, chemical resistance, hardness and adhesion along with the basic physical properties of the coating film.

The acrylic modified polyester resin may be obtained by copolymerizing a polyester resin and an acrylic monomer. The copolymerization reaction may be carried out under a catalyst, and non-limiting examples of catalysts that can be used include diteributyl peroxide, benzoyl peroxide, tertiarybutylperoxy-M-isopropyl benzene, and the like.

The polyester resin used in the production of the acrylic modified polyester resin of the present invention is not particularly limited as long as it is a polyester resin used in the relevant field. For example, a polyester resin prepared by reacting a polybasic acid and a polyhydric alcohol may be used.

Acrylic monomers used in the production of the acrylic modified polyester resin of the present invention are methyl methacrylate, normal butyl acrylate, normal butyl methacrylate, ethyl acrylate, ethyl methacrylate, glycidyl methacrylate, 2- It may be hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, methacrylic acid or acrylic acid, but is not limited thereto. These monomers may be used alone or in combination of two or more.

As an example, the acrylic monomer may be used in an amount of 10 to 30% by weight based on the polyester resin. When the acrylic monomer is used in an amount of less than 10% by weight, the hardness and stain resistance of the acrylic modified polyester resin may be weak. On the other hand, when the acrylic monomer is used in an amount exceeding 30% by weight, self-polymerization between the acrylic monomers occurs, and the viscosity of the acrylic-modified polyester resin may increase excessively and become opaque.

As an example, the glass transition temperature (Tg) of the acrylic modified polyester resin is 40 to 80 °C, for example 50 to 70 °C, the hydroxyl value (OH value) is 30 to 90 mgKOH/g, for example 50 to 70 mgKOH/g, the weight average molecular weight may be 20,000 to 40,000 g/mol, for example, 25,000 to 35,000 g/mol.

When using an acrylic-modified polyester resin having a glass transition temperature, a hydroxyl value and a weight average molecular weight in the above-described range, the solid content in the paint is increased, so that excellent coating properties can be exhibited in terms of corrosion resistance, weather resistance, and hardness.

The content of the acrylic modified polyester resin may be 5 to 30% by weight, for example, 10 to 20% by weight based on the total weight of the paint composition. When the content of the acrylic-modified polyester resin falls within the above-described range, the basic physical properties of the coating film are good, excellent corrosion resistance, chemical resistance and appearance characteristics may be expressed, and adhesion to other substrate layers may be improved.

Phosphoric acid modified polyester resin

The coating composition according to the present invention includes a phosphoric acid-modified polyester resin. The phosphoric acid-modified polyester resin serves to improve hardness, water resistance, and workability when forming a coating film.

The phosphoric acid-modified polyester resin may be prepared by polymerizing a polyester resin with a phosphoric acid (H ₃ PO _{4) salt.}

The polyester resin used in the production of the phosphoric acid-modified polyester resin of the present invention is not particularly limited as long as it is a polyester resin used in the field. For example, a polyester resin prepared by reacting a polybasic acid and a polyhydric alcohol may be used.

Non-limiting examples of phosphates that can be used in the polymerization include trimethyl 　 phosphate, triethyl 　 phosphate, tributyl 　 phosphate, butoxyethyl 　 phosphate, triphenyl 　 phosphate, trixylenyl phosphate, tris(isopropylphenyl) phosphate, naphthyl Phosphate, diphenyl (2-ethylhexyl) 　 phosphate, 2-acryloyloxy ethyl acid phosphate, 2-methacryloyloxy ethyl acid phosphate, diphenyl-2-acryloyloxyethyl 　 phosphate, diphenyl-2- Methacryloyloxyethyl phosphate, melamine phosphate, triphenyl phosphine oxide, and condensates thereof.

The acid value of the phosphoric acid-modified polyester resin may be 20 to 80 mgKOH/g, for example 40 to 60 mgKOH/g, and the solid content may be 40 to 70%, for example 50 to 60%, and viscosity (25° C.) may be 1,000 to 5,000 cps, for example, 2,000 to 3,700 cps. When the acid value, viscosity, and solid content of the phosphoric acid-modified polyester resin fall within the above-described ranges, the degree of curing of the coating film may be improved.

The content of the phosphoric acid-modified polyester resin may be 1 to 10% by weight, for example, 1 to 5% by weight based on the total weight of the coating composition. When the content of the phosphoric acid-modified polyester resin is out of the above-described range, a problem may occur in curability and moldability, and the strength may be relatively low.

Acrylic resin

The coating composition according to the present invention includes an acrylic resin. The acrylic resin can impart excellent corrosion resistance and appearance properties to the coating film.

The acrylic resin may be prepared by polymerizing a (meth)acrylate monomer and a vinyl monomer.

The kind of the (meth)acrylate monomer is not particularly limited, but, for example, N-methylol acrylamide, 2-hydroxypropyl methacrylate, propyl methacrylate, t-butylaminoethyl methacrylate, dicyclo Pentenyl oxyethyl methacrylate, acrylic acid dimer, hexanediol diacrylate, t-butyl acrylate, triisopropylsilyl acrylate, benzyl methacrylate, hydroxyethyl methacrylate phthalate, 2-hydroxyethyl methacrylate Rate, trimethylolpropane triacrylate, tripropylene glycol diacrylate, ethyl methacrylate, diacetone acrylamide, isobutyl methacrylate, hydroxyisopropyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate Rate, triisopropyl silyl methacrylate, isobornyl acrylate, t-butylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate, acrylonitrile, methyl methacrylate, acrylic acid, t-butyl methacrylate, iso One or more selected from bonyl methacrylate, methacrylonitrile, methacrylic acid, acrylamide, methacrylamide, chlorostyrene, and cyclohexyl vinyl ether may be used.

The kind of the vinyl monomer is not particularly limited, but for example, styrene, methylstyrene, dimethylstyrene, fluorostyrene, ethoxystyrene, methoxystyrene, phenylene vinyl ketone, vinyl t-butyl benzoate, vinyl cyclohexano Eight, vinyl acetate, vinyl pyrrolidone, vinyl chloride, vinyl alcohol, acetoxy styrene, t-butyl styrene, and at least one selected from vinyl toluene may be used.

The glass transition temperature (Tg) of the acrylic resin is 50 to 100 °C, for example 60 to 85 °C, the hydroxyl value (OH value) is 60 to 150 mgKOH/g, for example 90 to 130 mgKOH/g, weight average The molecular weight may be 50,000 to 65,000 g/mol, for example 55,000 to 60,000 g/mol, and the solid content may be 40 to 80%, for example 60 to 70%.

The content of the acrylic resin may be 1 to 20% by weight, for example, 1 to 15% by weight based on the total weight of the paint composition. When the content of the acrylic resin satisfies the above-described range, the leveling property, flexibility, and adhesion of the coating film may be improved.

Nitrocellulose resin

The coating composition according to the present invention includes a nitrocellulose resin. The nitrocellulose resin is an element that forms a coating film and plays a role of shortening the drying time of the coating composition and improving the luminance to realize an excellent appearance.

The nitrogen content in the nitrocellulose resin is not particularly limited, and a nitrocellulose resin having a nitrogen content of 10.9 to 12.2% by weight based on the total weight of the resin may be used. As an example, the nitrocellulose resin used in the present invention may be a resin having a nitrogen content of 11.8 to 12.2% by weight based on the total weight of the resin. When the nitrogen content of the nitrocellulose resin satisfies the above-described range, the brightness of the object to be coated can be effectively improved.

The glass transition temperature (Tg) of the nitrocellulose resin may be 30 to 130° C., for example, 50 to 100° C., and the viscosity (based on 25° C.) may be 200 to 1,500 cps, for example, 300 to 1,000 cps.

The content of the nitrocellulose resin may be 5 to 55% by weight, for example, 20 to 40% by weight based on the total weight of the coating composition. When the content of the nitrocellulose resin satisfies the above-described range, workability and brightness of the coating composition may be effectively improved.

Cured resin

The coating composition according to the present invention may further include a cured resin. The cured resin serves to form a stable coating film by causing a curing reaction with the aforementioned resin component.

The type of cured resin usable in the present invention is not particularly limited, but, for example, a urea resin, an isocyanate resin, a melamine resin, etc. may be used, and the cured resin used in the present invention is preferably a melamine resin.

The melamine resin may have a weight average molecular weight of 100 to 500 g/mol, for example 200 to 400 g/mol, and a solid content of 90 to 99%, for example 95 to 99%.

The type of melamine resin usable in the present invention is not particularly limited, and methoxy melamine resin, butoxy melamine resin, methoxy/butoxy mixed melamine resin, and the like may be used.

The content of the melamine resin may be 1 to 25% by weight, for example 3 to 20% by weight, based on the total weight of the coating composition. When the content of the melamine resin satisfies the above-described range, the degree of curing of the coating film may be increased, so that physical properties of the coating film may be improved.

Pigment

The paint composition according to the present invention may further include a pigment. The pigments may include conventional extender pigments, colored pigments, or mixtures thereof known in the art.

The extender pigment fills the pores in the coating film, complements the formation of the coating film, and serves to impart a rusting property or mechanical properties to the coating film. Therefore, when the extender pigment is included, a good coating film appearance can be obtained, and hardness, impact resistance, rust resistance, and the like can be improved. As the extender pigments, those commonly used in paint compositions may be used without limitation, examples of which include calcium carbonate, clay, talc, magnesium silicate, kaolin, mica, silica, aluminum silicate, aluminum hydroxide, barium sulfate, and the like. . The above-described components may be used alone or two or more of them may be used in combination.

Colored pigments can be used to express a desired color (color) in a paint or to increase the strength or gloss of a coating film. As such pigments, organic pigments, inorganic pigments, metallic pigments, aluminum-paste, pearl, etc., which are commonly used in paints, can be used without limitation, and these can be used alone or in combination of two or more. have. Non-limiting examples of color pigments that can be used include azo-based, phthalocyanine-based, iron oxide-based, cobalt-based, carbonate-based, sulfate-based, silicate-based, chromate-based pigments, and the like. Date, cyanine green, carbon black, iron oxide, sulfur iron oxide, navy blue, cyanine blue, and mixtures of two or more thereof.

For example, the coating composition according to the present invention may include a liquid metallic pigment, a solid metallic pigment, a metal paste (eg, aluminum paste), or a mixture thereof as a pigment. When at least one of the liquid metallic pigments, solid metallic pigments, and metal pastes is included, luminance is increased and color expression is excellent, so that the appearance properties of the object to be coated can be improved. The pigment used in the present invention is preferably a liquid metallic pigment.

The average particle size (D ₅₀ ) and solid content of the liquid metallic pigment are not particularly limited, but the average particle size is 5 to 15 µm, for example, 7 to 12 µm, and the solid content is 1 to 20%, for example It may be 5 to 15%. The average particle size (D ₅₀ ) and solid content of the metal paste are not particularly limited, but the average particle size is 10 to 20 µm, for example 12 to 17 µm, and the solid content is 60 to 80%, for example 65 To 75%.

The content of the pigment may be 1 to 25% by weight, for example 5 to 20% by weight, based on the total weight of the paint composition. When the content of the pigment satisfies the above-described range, the degree of curing of the coating film may be increased, so that physical properties of the coating film may be improved.

Hardening accelerator

The coating composition according to the present invention may further include a curing accelerator. The curing accelerator plays a role in accelerating the curing reaction and improving the cycle of high temperature reliability and continuous workability.

The curing accelerator used in the present invention may be used without particular limitation as long as it accelerates the curing reaction of the curing agent, and an amine compound, a phosphorus compound, an acid compound, and a tin compound may be used. As an example, the coating composition according to the present invention may include a tin-based compound such as dibutyltin dilaurate (DBTDL).

The content of the curing accelerator may be 0.1 to 15% by weight, for example, 1 to 10% by weight based on the total weight of the coating composition. When the content of the curing accelerator is out of the above-described range, workability and moldability may be deteriorated.

solvent

The coating composition according to the present invention may further include a solvent. As the solvent, conventional organic solvents known in the art may be used without limitation.

As the organic solvent, an aromatic hydrocarbon-based solvent, an ester-based solvent, an ether-based solvent, an alcohol-based solvent, or a mixture thereof may be used. Non-limiting examples of usable organic solvents include cyclohexanone, xylene, toluene, cellosolve acetate, methyl ethyl ketone, dibasic ester, propylene glycol methyl ether acetate, butyl acetate, ethyl acetate, propylene glycol monomethyl acetate, 3-methoxy butyl acetate, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, methanol, ethanol, isopropanol, n-butanol, amyl alcohol, butyl carbitol, isophorone or And mixed solvents thereof.

In the present invention, the content of the solvent may be a residual amount that satisfies the total weight (100% by weight) of the coating composition, and may be, for example, 1 to 30% by weight based on the total weight of the coating composition. When the content of the solvent falls within the above-described range, workability may be improved and excellent physical properties of the coating film may be exhibited.

additive

The coating composition of the present invention may optionally further include additives commonly used in the coating field within a range that does not impair the inherent properties of the composition.

Non-limiting examples of additives that can be used in the present invention include dispersing agents, defoaming agents, defoaming agents, leveling agents, plasticizers, ultraviolet absorbers, surface modifiers, softening agents, adhesion promoters, wetting agents, or mixtures thereof.

The dispersant plays a role of dispersing each material constituting the composition and preventing re-aggregation by maintaining a distance, thereby expressing the uniform physical properties of the coating film. As the dispersant, conventional ones known in the art may be used, and as an example, a high molecular weight block copolymer type dispersant may be used.

The antifoaming agent serves to enhance the appearance of the coating film by suppressing air bubbles generated during coating, and a conventional antifoaming agent known in the art may be used without limitation. For example, a silicone-based or non-silicone-based antifoaming agent may be used, and as an example, a polysiloxane type antifoaming agent may be used.

The leveling agent is for improving the appearance properties of the coating film while improving the adhesion in the composition by leveling the composition so that it is coated flat and smoothly. As the leveling agent, conventional ones known in the art may be used without limitation, and examples include acrylic, silicone, polyester, and amine leveling agents.

Plasticizers play a role in controlling the viscosity of the coating composition and improving storage stability. As the plasticizer, a conventional plasticizer known in the art may be used without limitation, and as an example, an acrylic plasticizer may be used.

The additive may be added within the content range known in the art, and for example, may be included in an amount of 0.1 to 25% by weight based on the total weight of the coating composition. When the content of the additive is within the above-described range, the appearance and hardness of the coating film may be improved.

The present invention will be described in more detail through the following examples. However, the following examples are only intended to aid understanding of the present invention, and the scope of the present invention is not limited to the examples in any sense.

[Example 1-10]

Each component was mixed according to the composition shown in Tables 1 and 2 below, to prepare a coating composition of Example 1-10. The unit of use of each component in Tables 1 and 2 is parts by weight.

[Table 1]

[Table 2]

[Comparative Example 1-3]

A coating composition of Comparative Example 1-3 was prepared in the same manner as in the above Example, except that it was according to the composition of Table 3 below. The unit of use of each component in Table 3 is parts by weight.

[Table 3]

Acrylic modified polyester resin 1: Glass transition temperature of 52 ℃, hydroxyl value 62 mgKOH/g, weight average molecular weight 26,500 g/mol

Acrylic modified polyester resin 2: Glass transition temperature 67 ℃, hydroxyl value 55 mgKOH/g, weight average molecular weight 33,000 g/mol

Acrylic modified polyester resin 3: glass transition temperature 32 ℃, hydroxyl value 10 mgKOH/g, weight average molecular weight 18,000 g/mol

Polyester resin: Glass transition temperature of 50 ℃, hydroxyl value 65 mgKOH/g, weight average molecular weight 28,000 g/mol

Phosphoric acid modified polyester resin 1: acid value 48 mgKOH/g, solid content 55%, viscosity (25 ℃) 2,500 cps

Phosphoric acid modified polyester resin 2: acid value 55 mgKOH/g, solid content 59%, viscosity (25 ℃) 3,500 cps

Phosphoric acid modified polyester resin 3: acid value 18 mgKOH/g, solid content 55%, viscosity (25 ℃) 1,500 cps

Acrylic resin: glass transition temperature of 72 ℃, hydroxyl value 113 mgKOH/g, weight average molecular weight 57,000 g/mol, solid content 65%

Nitrocellulose resin 1: glass transition temperature of 80 ℃, nitrogen content 11.8 to 12.2% by weight (based on the total weight of the nitrocellulose resin), viscosity (based on 25 ℃) 700 cps, solid content 5%

Nitrocellulose resin 2: glass transition temperature of 80 ℃, nitrogen content 10.9 to 11.2% by weight (based on the total weight of the nitrocellulose resin), viscosity (based on 25 ℃) 700 cps, solid content 5%

Melamine resin: weight average molecular weight 306 g/mol, solid content 97%

Pigment: Liquid metallic silver (average particle size D ₅₀ 9 ㎛, solid content 10%)

Hardening accelerator: B-CAT 0019 (FTC KOREA) 50% diluted

Solvent 1: Butyl Cellosolve

Solvent 2: isophorone

Solvent 3: Butyl Carbitol

UV absorber 1: TINUVIN-123 (BASF company)

UV absorber 2: TINUVIN-400 (BASF company)

Surface modifier 1: TEGO FLOW ZFS460 (EVONIK)

Surface modifier 2: Thermoplastic acrylic resin (KCC company)

Defoamer: DISPARLON OX-883 (KUSUMOTO CHEMICALS)

Colored Pigment 1: Acrylic Yellow Pigment

Colored Pigment 2: Polyester Red Pigment

Colored Pigment 3: Polyester Black Pigment

Acrylic plasticizer: Benzoflex 9-88 (EASTMAN CHEMICAL)

[Physical property evaluation]

After measuring the physical properties of the coating composition prepared according to each Example and Comparative Example as shown in Table 4 below, the results are shown in Tables 5 to 7.

As shown in Tables 5 to 7, the coating film formed of the coating composition of Examples 1-10 according to the present invention was generally superior to the coating film formed of the coating composition of Comparative Example 1-3. In particular, it was confirmed that the coating film formed of the coating composition of Example 1-10 secured a high luminance of 18 or more based on the FI value (Flop Index), and also excellent coating properties such as heat resistance and chemical resistance.

Claims (6)

A coating composition comprising an acrylic-modified polyester resin, a phosphoric acid-modified polyester resin, an acrylic resin, and a nitrocellulose resin. The method of claim 1, wherein the acrylic-modified polyester resin has a glass transition temperature (Tg) of 40 to 80 °C, a hydroxyl value (OH value) of 30 to 90 mgKOH/g, and a weight average molecular weight of 20,000 to 40,000 g/ The coating composition in mol. The coating composition of claim 1, wherein the phosphoric acid-modified polyester resin has an acid value of 20 to 80 mgKOH/g and a viscosity (25° C.) of 1,000 to 5,000 cps. The coating according to claim 1, wherein the acrylic resin has a glass transition temperature (Tg) of 50 to 100 °C, a hydroxyl value (OH value) of 60 to 150 mgKOH/g, and a weight average molecular weight of 50,000 to 65,000 g/mol. Composition. The method of claim 1, wherein the nitrocellulose resin has a nitrogen content of 10.9 to 12.2% by weight based on the total weight of the nitrocellulose resin, a glass transition temperature (Tg) of 30 to 130°C, and a viscosity (based on 25°C). The coating composition is 200 to 1,500 cps. The method of claim 1, wherein the acrylic modified polyester resin 5 to 30% by weight, phosphoric acid modified polyester resin 1 to 10% by weight, acrylic resin 1 to 20% by weight, and nitrocellulose resin 5 to 55 based on the total weight of the coating composition. Paint composition comprising weight percent.