KR20200068294A - Base coat composition - Google Patents

Abstract

The present invention relates to a base coat composition comprising polyester polyol, acrylic polyol, cellulose acetate butyrate, metal paste and solvent.

Description

Base coat composition {BASE COAT COMPOSITION}

The present invention relates to a base coat composition.

In the case of plastic parts applied to automobiles, it is common to perform pretreatment, primer coating, base coat and clear coat coating to protect the surface from external and external environments. In addition, the conventional base coat composition includes a thermosetting resin, for example, a polyester resin, an amino acrylic resin, a polyester urethane rubber, an acrylic urethane rubber, a polyester melamine resin, an acrylic melamine resin, or the like.

In this regard, Korean Patent Publication No. 2015-0071907 (Patent Document 1) includes a primer composition containing a polyester resin as a main resin component; And a two-component non-ferrous metal coating agent comprising; a top composition comprising a resin selected from acrylic polyol resin, cellulose acetate butyrate resin and polyethylene and polyethylene-propylene copolymer as the main resin component. However, as in Patent Document 1, the conventional base coat composition containing a thermosetting resin is in a liquid state before the curing reaction, but the appearance quality of the final part is influenced by the thermosetting resin crosslinked by the painting process. However, the appearance quality of conventional automobile parts is inferior to that of a vehicle body, and thus there is an increasing demand for improving the appearance quality.

Therefore, there is a need for research and development for the base coat composition having excellent appearance characteristics, adhesion, water resistance and weather resistance, and excellent coating workability.

Korean Patent Publication No. 2015-0071907 (Publication date: 2015.6.29.)

Accordingly, the present invention is to provide a base coat composition excellent in appearance properties, adhesion, water resistance and weather resistance of the prepared coating film, and excellent coating workability.

The present invention provides a base coat composition comprising polyester polyol, acrylic polyol, cellulose acetate butyrate, metal paste and solvent.

The base coat composition according to the present invention has excellent coating workability, and the coating film prepared therefrom has excellent appearance characteristics, adhesion, water resistance, chemical resistance, impact resistance and weather resistance, and can be usefully used for automobile parts.

Hereinafter, the present invention will be described in detail.

In this specification, “(meth)acrylic” means “acrylic” and/or “methacryl”, and “(meth)acrylate” means “acrylate” and/or “methacrylate”.

The molecular weight used herein is measured by a conventional method known in the art, for example, it can be measured by a gel permeation chromatograph (GPC) method. In addition, the glass transition temperature is measured by a conventional method known in the art, and can be measured, for example, by differential scanning calorimetry (DSC).

Base coat composition

The base coat composition according to the invention comprises polyester polyol, acrylic polyol, cellulose acetate butyrate, metal paste and solvent.

Polyester polyol

Polyester polyol serves to improve the appearance properties, curing density, adhesion, moisture resistance and impact resistance of the coating film prepared from the composition comprising the same.

The polyester polyol may be directly synthesized according to a known method, or a commercially available product may be used. Specifically, the polyester polyol may be prepared by a condensation reaction of a glycol monomer and a monomer containing a carboxyl group.

In this case, the glycol monomer is, for example, neopentyl glycol, trimethylolpropane, diethylene glycol, triethylene glycol, 1,6-hexanediol, 1,4-butanediol, 1,4-cyclohexane amethanol and their And mixtures.

In addition, the monomer containing the carboxyl group includes, for example, terephthalic acid, maleic anhydride, fumaric acid, phthalic anhydride, isophthalic acid, tetrahydrophthalic anhydride, adipic acid and mixtures thereof.

Furthermore, the polyester polyol may have a hydroxyl value (OHv) of 100 to 150 mgKOH/g. Specifically, the polyester polyol may have a hydroxyl value of 110 to 145 mgKOH/g, or 120 to 140 mgKOH/g. When the hydroxyl value of the polyester polyol is within the above range, the weather resistance of the prepared coating film may be particularly excellent, and when the hydroxyl value of the polyester polyol is outside the above range, weather resistance and chemical resistance may be deteriorated.

The polyester polyol may have an acid value (Av) of 0.1 to 5 mgKOH/g or 0.5 to 4 mgKOH/g. When the acid value of the polyester polyol is within the above range, there is an effect that the workability of the composition and the weather resistance of the prepared coating film are improved.

In addition, the polyester polyol may have a solids content of 60 to 90% by weight or 70 to 90% by weight based on the total weight. When the solid content of the polyester polyol is within the above range, there is an effect of improving the chemical resistance and weather resistance of the prepared coating film.

The weight average molecular weight of the polyester polyol may be 2,000 to 8,000 g/mol or 3,000 to 7,000 g/mol. When the weight average molecular weight of the polyester polyol is within the above range, the appearance properties of the prepared coating film and workability of the composition may be excellent, and when the weight average molecular weight of the polyester polyol is outside the above range, the appearance of the produced coating film Properties, workability and adhesion of the composition may be degraded.

In addition, the polyester polyol may be included in the composition in an amount of 20 to 40 parts by weight or 22 to 36 parts by weight based on 5 to 20 parts by weight of the acrylic polyol. When the content of the polyester polyol is within the above range, the appearance characteristics of the coating film prepared from the composition containing the composition are improved, and hardness deterioration of the coating film is prevented.

Acrylic polyol

The acrylic polyol serves to improve the dryness of the composition containing it, and the appearance properties of the coating film to be produced.

The acrylic polyol may be directly synthesized according to a known method, or a commercially available product may be used. Specifically, the acrylic polyol is 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate , 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, at least 1 such as ethylene glycol di(meth)acrylate and 1,6-hexanediol di(meth)acrylate It may include a repeating unit derived from an acrylic monomer having more than one hydroxyl group. In addition, the acrylic polyol may be prepared by copolymerizing an acrylic monomer having at least one or more hydroxyl groups as described above and a monomer containing an unsaturated bond.

At this time, the monomer containing the unsaturated bond may be at least one selected from the group consisting of styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate. .

In addition, the acrylic polyol may have a hydroxyl value (OHv) of 20 to 100 mgKOH/g or 30 to 85 mgKOH/g, and another example may be 30 to 70 mgKOH/g. When the hydroxyl value of the acrylic polyol is within the above range, the chemical resistance of the prepared coating film may be particularly excellent, and when the hydroxyl value of the acrylic polyol is outside the above range, the chemical resistance and water resistance of the prepared coating film may be deteriorated. .

The acrylic polyol may have a viscosity at 25°C of 30 to 100 cPs (centipoise) or a viscosity at 25°C of 40 to 90 cPs, and another example may be 40 to 75 cPs. When the viscosity at 25°C of the acrylic polyol is within the above range, the workability of the composition may be particularly excellent, and when the viscosity at 25°C of the acrylic polyol is outside the range, workability and appearance may be deteriorated. .

The acrylic polyol may have an average particle size of 100 to 500 nm or 200 to 450 nm, and another example may be 240 to 340 nm. When the average particle size is within the above range, the acrylic polyol has an effect of improving the appearance characteristics of the prepared coating film.

Furthermore, the acrylic polyol may have a solids content of 30 to 70% by weight based on the total weight. Specifically, the acrylic polyol may have a solids content of 35 to 65% by weight, or 40 to 60% by weight based on the total weight. When the solid content of the acrylic polyol is within the above range, there is an effect of improving the appearance and water resistance of the prepared coating film, and when the solid content of the acrylic polyol is outside the above range, the appearance, water resistance and hardness of the prepared coating film are lowered. Can be.

In addition, the acrylic polyol may be included in the composition in an amount of 5 to 20 parts by weight based on 20 to 40 parts by weight of the polyester polyol. Specifically, the acrylic polyol may be included in the composition in an amount of 5 to 15 parts by weight, or 5 to 10 parts by weight based on 20 to 40 parts by weight of the polyester polyol. When the content of the acrylic polyol is within the above range, a problem in that the dryness of the composition containing it is lowered, and a problem in which the appearance characteristics of the prepared coating film is lowered can be prevented.

Cellulose Acetate Butyrate

Cellulose acetate butyrate is a thermoplastic resin, and acts as a binder in a composition containing the same to improve the adhesion performance of the composition to the plastic material and to improve the dryness of the prepared coating film. The cellulose acetate butyrate (CAB) refers to a cellulose derivative obtained by partially acetylating and butyl esterifying cellulose.

The cellulose acetate butyrate may have a melting point (Tm) of 100 to 250°C or 110 to 230°C, and another example of 125 to 210°C. When the melting point of the cellulose acetate butyrate is within the above range, there is an effect of improving the gloss and weather resistance of the prepared coating film.

The cellulose acetate butyrate may have a glass transition temperature (Tg) of 80 to 150°C or 90 to 150°C. When the glass transition temperature of the cellulose acetate butyrate is within the above range, there is an effect of improving the appearance and workability of the composition, and when the glass transition temperature of the cellulose acetate butyrate is outside the above range, the prepared coating film The appearance, workability and hardness of the composition may be reduced.

The cellulose acetate butyrate may have a number average molecular weight (Mn) of 10,000 to 50,000 g/mol or 12,000 to 40,000 g/mol. When the number average molecular weight of the cellulose acetate butyrate is within the above range, the weather resistance of the prepared coating film is improved, and when the number average molecular weight of the cellulose acetate butyrate is outside the above range, the weather resistance and appearance of the prepared coating film may be lowered. Can be.

In addition, the cellulose acetate butyrate may have a butyl group content of 30 to 50% by weight, an acetyl group content of 10 to 30% by weight, and a hydroxy group content of 1 to 10% by weight based on the total weight. Specifically, the cellulose acetate butyrate may have a butyl group content of 35 to 45% by weight, an acetyl group content of 10 to 22% by weight, and a hydroxy group content of 1 to 5% by weight based on the total weight. When the butyl group content of the cellulose acetate butyrate is within the above range, the chemical resistance and weather resistance of the prepared coating film are improved, and when the acetyl group content is within the above range, the heat resistance and appearance characteristics of the prepared coating film are improved. There is, when the hydroxy group content is within the above range, there is an effect that the weather resistance of the prepared coating film is improved.

In addition, the cellulose acetate butyrate may be included in the composition in an amount of 5 to 30 parts by weight based on 20 to 40 parts by weight of polyester polyol. Specifically, the cellulose acetate butyrate may be included in the composition in an amount of 10 to 25 parts by weight, or 10 to 20 parts by weight based on 20 to 40 parts by weight of polyester polyol. When the content of the cellulose acetate butyrate is within the above range, it is possible to prevent a problem that the dryness of the composition containing it is lowered and a problem that the appearance characteristics of the prepared coating film is lowered.

Metal paste

The metal paste imparts brightness and hiding power to the coating film prepared from the base coat composition including the same.

The metal paste may include one or more metals selected from the group consisting of silver, zinc, copper, gold, nickel, and titanium. Specifically, the metal paste may include silver.

Further, the metal paste may include a binder. At this time, the binder may be, for example, acrylic resin, phenol resin, cellulose, and the like.

Furthermore, the metal paste may have a solid content of 50 to 100% by weight based on the total weight. Specifically, the metal paste may have a solid content of 70 to 100% by weight based on the total weight. When the solid content of the metal paste is within the above range, there is an effect that the hiding power of the prepared coating film is improved.

In addition, the metal paste may be included in the composition in an amount of 5 to 15 parts by weight or 5.5 to 14 parts by weight based on 20 to 40 parts by weight of polyester polyol. When the content of the metal paste is within the above range, it is possible to prevent a problem in which luminance, hiding power and appearance characteristics of a coating film prepared from a composition containing the same are lowered, and a problem of deteriorating economic efficiency by increasing manufacturing cost.

solvent

The solvent serves to improve the workability by adjusting the viscosity of the composition containing it.

The solvent is, for example, non-polar solvents such as n-heptane, toluene, xylene, petroleum compounds and n-hexane; Ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, dibasic ester, 3-methoxy butyl acetate, amyl acetate, butyl glycol acetate, methyl ethyl ketone, methyl isobutyl ketone, acetone, diiso Polar solvents such as butyl ketone, isophorone and cyclohexanone; And mixtures of the non-polar solvent and the polar solvent, and may be appropriately selected and used depending on the properties or volatilization speed of the resin contained in the composition.

Specifically, the solvent may be a mixed solvent containing two or more solvents. In this case, the mixed solvent may be a mixture of an ester-based solvent and a ketone-based solvent. For example, the mixed solvent may include a mixture of n-butyl acetate and methyl isobutyl ketone, a mixture of n-butyl acetate and butyl cellosolve acetate, a mixture of n-butyl acetate and xylene, and the like. When a mixed solvent is used as the solvent, the workability of the composition and the appearance characteristics of the prepared coating film are excellent.

The mixed solvent may include an ester-based solvent and a ketone-based solvent in a volume ratio of 1:0.1 to 1:0.3. When the mixed solvent includes an ester-based solvent and a ketone-based solvent within the volume ratio range, there is an excellent effect of coating composition workability and appearance characteristics of the prepared coating film.

In addition, the solvent may be included in the composition in an amount of 10 to 35 parts by weight based on 20 to 40 parts by weight of polyester polyol. Specifically, the solvent may be included in the composition in an amount of 10 to 30 parts by weight based on 20 to 40 parts by weight of polyester polyol. When the content of the solvent is within the above range, it is possible to prevent a problem in which adhesion and weather resistance of a coating film prepared from a composition containing the same are lowered, and a problem of poor workability due to too high a viscosity.

additive

The base coat composition may further include at least one additive selected from the group consisting of viscosity modifiers, ultraviolet absorbers, colorants and surface modifiers.

The viscosity modifier serves to improve workability by adjusting the viscosity of the base coat composition. In addition, the viscosity modifier may include, for example, wax, polyvinyl chloride (PVC), polyurethane (PU), fluidity modifier, and thermoplastic.

In addition, the viscosity modifier may be included in the composition in an amount of 20 to 70 parts by weight based on 100 parts by weight of the polyester polyol. Specifically, the viscosity modifier may be included in the composition in an amount of 30 to 50 parts by weight based on 100 parts by weight of the polyester polyol. When the content of the viscosity modifier is within the above range, there is an effect of excellent coating workability and paint storage.

The ultraviolet absorber has stronger ultraviolet (UV) absorption performance than the chromophore of the acrylic resin, thereby suppressing the generation of radicals in the acrylic resin, and serves to prevent discoloration, swelling, interlayer peeling, and loss of luster of the acrylic resin.

The ultraviolet absorber may be a benzotriazole-based ultraviolet absorber. For example, the benzotriazole-based ultraviolet absorber is α-[3-[3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenyl]-1 -Oxapropyl]-ω-hydroxypoly(oxy-1,2-ethanediyl), α-[3-[3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl) )-4-hydroxyphenyl]-1-oxapropyl]-ω-[3-[3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy Phenyl]-1-oxapropoxy]poly(oxy-1,2-ethanediyl), 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy -Methyl ester, hydroxyphenyl benzotriazole, and the like.

Furthermore, the ultraviolet absorber may be included in the composition in an amount of 1 to 10 parts by weight based on 100 parts by weight of the polyester polyol. Specifically, the ultraviolet absorber may be included in the composition in an amount of 2 to 5 parts by weight based on 100 parts by weight of the polyester polyol. When the content of the ultraviolet absorber is within the above range, it is possible to prevent a problem that the manufacturing cost increases and the economical efficiency decreases, and a problem that the weather resistance of a coating film prepared from a composition containing the same decreases.

The colorant serves to impart color to the composition, and is not particularly limited as long as it can be included in the coating composition. For example, the colorant may be at least one selected from the group consisting of inorganic pigments and organic pigments. For example, the colorant is a metal oxide such as titanium dioxide, carbon black, zinc oxide, ultramarine, red iron oxide; Sulfides of lithopone, lead, cadmium, iron, cobalt, aluminum and hydrochloride or sulfates thereof; Azo pigments; And copper phthalocyanine pigments.

In addition, the colorant may be included in the composition in an amount of 5 to 30 parts by weight based on 100 parts by weight of the polyester polyol. Specifically, the colorant may be included in the composition in an amount of 15 to 25 parts by weight based on 100 parts by weight of the polyester polyol. When the content of the colorant is within the above range, there is an effect that the coating film hiding power and coating workability are excellent.

The surface adjuster serves to control the smoothness of the coating layer by adjusting the surface tension after application of the coating composition, and can be used without particular limitation, as long as it is a common one that can be used in the coating composition. For example, the surface modifier may be a polysiloxane-based or non-silicone-based surface modifier.

In addition, the surface control agent may be included in the composition in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the polyester polyol. Specifically, the surface modifier may be included in the composition in an amount of 0.1 to 0.3 parts by weight based on 100 parts by weight of the polyester polyol. When the content of the surface control agent is within the above range, there is an excellent effect of coating film leveling properties and coating appearance.

The base coat composition has a viscosity of 50 to 70 KU (krebs unit) at 25°C, and may include 30 to 60% by weight of solids based on the total weight of the composition. Specifically, the base coat composition has a viscosity of 55 to 65 KU (krebs unit) at 25°C, and may include 35 to 50% by weight of solids based on the total weight of the composition.

The base coat composition according to the present invention as described above has excellent coating workability, and the coating film prepared therefrom has excellent appearance characteristics, adhesion, water resistance, chemical resistance, impact resistance and weather resistance, and is useful for automotive parts. Can be.

Base paint kit

The base coating kit according to the present invention includes a base coat composition as described above; And a curing agent.

Hardener

The curing agent serves to cure the base coat composition, and a conventional curing agent used to cure the acrylic coating composition may be used. Specifically, the curing agent may include an isocyanate-based resin.

In addition, the isocyanate group of the isocyanate-based resin reacts with the hydroxyl group of the acrylic polyol resin of the coating composition to form a urethane bond, thereby curing the coating composition. The isocyanate-based resin may be used without particular limitation, as long as it is a common one that can be used in a curing agent for paints. For example, as the isocyanate-based resin, hexamethylene diisocyanate (HMDI) having excellent yellowing resistance and weather resistance may be used.

Meanwhile, the curing agent may be diluted with an organic solvent, stored in a separate container, and sufficiently stirred immediately before use. At this time, the organic solvent is not particularly limited as long as it is a common one used in the coating composition.

2 component type

The base coating kit is a two-component coating kit comprising a base coat composition and a curing agent as described above. Specifically, the base coat composition and the curing agent may be used by mixing each of these immediately before use after storing them in separate containers.

The base coating kit may include 1:0.8 to 1:1.5 based on the equivalent ratio of the hydroxyl group of the base coat composition and the isocyanate of the curing agent. Specifically, the base coating kit may include 1:0.9 to 1:1.2 based on the equivalent ratio of the hydroxyl group of the base coat composition and the isocyanate of the curing agent. When the mixing ratio of the base coat composition and the curing agent is out of the above range, the dryness of the coating film prepared therefrom may be lowered or the curing reactivity of the coating may be lowered, resulting in insufficient coating film properties.

The base coating kit as described above may form a coating film having excellent appearance characteristics, adhesion, water resistance, chemical resistance, impact resistance, and weatherability by including the base coat composition as described above, whereby the base coating kit is an automobile. It can be used as a paint for parts.

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

[Example]

Examples 1 and 10

Using each component with the composition as shown in Table 1 below, the silver paste, the solvent, the wax and the colorant were placed in a container and stirred, and then polyester polyol, acrylic polyol resin and cellulose acetate butyrate were added to the container and the stirrer was used. After mixing at low speed, UV absorbers, surface conditioners and solvents were added and stirred for 30 minutes. Subsequently, a base coat composition was prepared by adding a solvent so that the viscosity at 25°C became 60 KU.

Subsequently, a base coating composition was prepared by mixing hexamethylene diisocyanate (HMDI) as a curing agent so that the equivalent ratio of the hydroxyl group of the base coat composition and the isocyanate of the curing agent was 1:1. The prepared base coating composition was adjusted to 15 to 17 seconds based on Ford Cup #4 by adding thinner to the viscosity.

Ingredient (parts by weight) Example One 2 3 4 5 6 7 8 9 10 Polyester polyol 1 28 30 - - 30 30 22 36 28 30 Polyester polyol 2 - - 28 - - - - - - - Polyester polyol 3 - - - 28 - - - - - Acrylic polyol1 7 7 - - 7 7 10 5 10 7 Acrylic polyol 2 - - 7 - - - - - - - Acrylic polyol 3 - - - 7 - - - - - - Cellulose Acetate Butyrate 1 16 14 - - - - 19 10 16 14 Cellulose Acetate Butyrate 2 - - - 16 14 - - - - - Cellulose Acetate Butyrate 3 - - 16 - - 14 - - - - Silver paste 8.5 8.5 8.5 8.5 8.5 8.5 8.5 8.5 5.5 14 Wax 12 12 12 12 12 12 12 12 12 10 Colorant 5 5 5 5 5 5 5 5 5 4 UV absorber 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.85 0.8 Surface adjuster 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 solvent 22.6 22.6 22.6 22.6 22.6 22.6 22.6 22.6 22.6 20.15 total 100 100 100 100 100 100 100 100 100 100

[Comparative example]

Comparative Examples 1 and 6

After using each component in a composition as described in Table 2 below, a silver paste, a solvent, a wax, and a colorant were placed in a container and stirred, and then polyester polyol, acrylic polyol resin, and cellulose acetate butyrate were added to the container, and a stirrer was used. After mixing at low speed, UV absorbers, surface conditioners and solvents were added and stirred for 30 minutes. Subsequently, a base coat composition was prepared by adding a solvent so that the viscosity at 25°C became 60 KU.

Subsequently, a base coating composition was prepared by mixing hexamethylene diisocyanate (HMDI) as a curing agent so that the equivalent ratio of the hydroxyl group of the base coat composition and the isocyanate of the curing agent was 1:1. The prepared base coating composition was adjusted to 15 to 17 seconds based on Ford Cup #4 by adding thinner to the viscosity.

Ingredient (parts by weight) Comparative example One 2 3 4 5 6 Polyester polyol 1 51 - - 33 34 - Acrylic polyol1 - 51 - - 17 20 Cellulose Acetate Butyrate 1 - - 51 18 - 25 Silver paste 8.5 8.5 8.5 8.5 8.5 15 Wax 12 12 12 12 12 11.5 Colorant 5 5 5 5 5 5 UV absorber 0.85 0.85 0.85 0.85 0.85 0.85 Surface adjuster 0.05 0.05 0.05 0.05 0.05 0.05 solvent 22.6 22.6 22.6 22.6 22.6 22.6 total 100 100 100 100 100 100

Hereinafter, the manufacturer and product name of each component used in Examples and Comparative Examples are shown below.

-Polyester polyol 1: 80% by weight of solid content, 130 mgKOH/g hydroxyl value, 2 mgKOH/g acid value, and weight average molecular weight 5,300 g/mol

-Polyester polyol 2: Solid content 70% by weight, hydroxyl value 121 mgKOH/g, acid value 1.2 mgKOH/g, weight average molecular weight 3,400 g/mol

-Polyester polyol 3: Solid content 90% by weight, hydroxyl value 137 mgKOH/g, acid value 3.8 mgKOH/g, weight average molecular weight 6,650 g/mol

-Acrylic polyol 1: 50% by weight of solid content, 50 mgKOH/g hydroxyl value, average particle size 290 nm, viscosity 60 cPs at 25°C

-Acrylic polyol 2: Solid content 43% by weight, hydroxyl value 31 mgKOH/g, average particle size 240 nm, viscosity at 25°C 40 cPs

-Acrylic polyol 3: 60% by weight of solid content, 68 mgKOH/g hydroxyl value, average particle size 330 nm, viscosity at 25°C 71 cPs

-Cellulose acetate butyrate 1: melting point 155 ℃, butyl content 37% by weight, acetyl content 13% by weight, hydroxyl group content 1.5% by weight, number average molecular weight 20,000 g/mol, glass transition temperature 123 ℃

Cellulose Acetate Butyrate 2: Melting Point 200 ℃, Butyl Content 45% by Weight, Acetyl Content 22% by Weight, Hydroxy Group Content 2.5% by Weight, Number Average Molecular Weight 35,000 g/mol, Glass Transition Temperature 148℃

Cellulose Acetate Butyrate 3: Melting Point 130 ℃, Butyl Content 31 wt%, Acetyl Content 10 wt%, Hydroxy Group Content 1 wt%, Number Average Molecular Weight 12,000 g/mol, Glass Transition Temperature 91 ℃

-Wax: Synthetic Wax (HUNGSAN HWASUNG / HPA-405)

-Colorant: (KCC / YX1211E)

-UV absorber: Benzotriazole (EVERLIGHT CHEMICAL INDUSTRIAL / EVERSORB 81)

-Surface modifier: Polysiloxane (BORCHER GMBH / Borchi Gol OL17)

-Solvent: butyl acetate and methyl isobutyl ketone (included in a volume ratio of 1:0.15)

Test Example: Evaluation of properties of the prepared coating film

An oil-soluble primer coating (manufacturer: KCC, product name: RP2143(H)-GREY) (dry film thickness: 10 μm) was coated on a plastic material (polypropylene bumper) and left to stand at room temperature for 5 minutes. Subsequently, the base coating compositions of the above Examples and Comparative Examples (dry film thickness: 15 to 20 μm) were coated and left at room temperature for 5 minutes. Then, an oil-soluble clear paint (manufacturer: KCC, product name: UT595-CLEAR) (dry film thickness: 33 µm) was coated and cured with hot air at 80°C for 30 minutes to prepare a final coating film. The workability of the coating composition, the appearance properties and properties of the final coating film were measured by the following methods, and the results are shown in Tables 3 and 4.

(1) Paintability

The base coating composition was coated twice by using IWATA 61 on a 30 cm x 40 cm tin plate, and the degree of atomization, smoothness, and paintability of the coating were compared during painting.

Specifically, excellent when the coating thickness of the coating layer is 10 µm or more (◎), good when the coating thickness of the coating layer is 2 µm or more and less than 10 µm (○), and the coating thickness of the coating layer is 6 µm or more and 8 µm If less than normal (△), twice the coating thickness of the film is less than 6㎛ was evaluated as defective (×).

(2) Appearance

The CF value was measured using a wave scan DOI (BYK Gardner), an automotive exterior measuring device, for the final coating film, and it was determined that the higher the CF value, the better the appearance characteristics of the coating film. Specifically, when the CF value was 40 or more, it was evaluated as excellent (◎), good (○) when 30 or more and less than 40, normal (Δ) when 25 or more and less than 30, and poor (×) when less than 25.

(3) Adhesion

According to the ASTM D3359 tape adhesion test method, the adhesiveness was evaluated by measuring the degree of peeling after the tape adhesion test on 100 squares of 1 mm × 1 mm (horizontal × vertical).

At this time, if 100 squares are 100% intact, excellent (◎), if the remaining square is 95% or more and less than 100%, good (○), 85% or more and less than 95%, normal (△), and less than 85%, bad ( ×).

(4) Water resistance

After depositing the final coating film in a constant temperature bath at 40°C for 10 days, adhesion was measured in the same manner as in item (3), and the evaluation criteria were applied in the same manner to evaluate the water resistance of the coating film.

(5) Weatherability

The adhesion of the coating film before and after exposure was compared with an energy of 2500 kJ using a xenon weatherometer tester. At this time, the adhesion test method and evaluation criteria were applied and performed in the same manner as in item (3).

(6) Chemical resistance

The chemical resistance was measured by wrapping the weight (4 cm in diameter) of a 4.9 N load with gauze soaked with a prescribed chemical (lead-free gasoline and industrial acetone), rubbing the surface of the final coating film 10 times, and measuring the gray scale of the appearance. Specifically, excellent for gray scale 4.5 or higher (◎), good for gray scale 4 or higher and less than 4.5 (○), normal for gray scale 3.5 or higher and less than 4 (△), poor for gray scale lower than 3.5 (( ×).

(7) Heat resistance

After immersing the final coating film in an 80°C constant temperature bath for 300 hours, an adhesion test was conducted in the same manner as in item (3), and the evaluation criteria were also applied to evaluate the heat resistance of the coating film.

(8) Hardness

The surface of the final coating film was measured for hardness using a Mitsubishi pencil. Specifically, the maximum hardness without damaging the final coating film was measured using Mitsubishi's prescribed pencil.

When the gray scale was 4B or more, it was evaluated as excellent (◎), 3B was good (○), 2B was normal (△), and 1B or less was evaluated as poor (×).

Example ingredient One 2 3 4 5 6 7 8 9 10 Painting workability ◎ ◎ ○ ◎ ◎ ◎ ◎ ◎ ○ ○ Exterior ◎ ◎ ◎ ○ ○ ◎ ○ ○ ○ ○ Adhesion ◎ ◎ ○ ◎ ◎ ◎ ○ ◎ ◎ ◎ Water resistance ◎ ◎ ○ ◎ ○ ◎ ◎ ◎ ◎ ◎ Weatherability ◎ ◎ ◎ ○ ◎ ◎ ◎ ◎ ◎ ◎ Chemical resistance white gas ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ Industrial acetone ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ Heat resistance ◎ ◎ ○ ◎ ◎ ○ ◎ ◎ ◎ ◎ Hardness ◎ ◎ ◎ ○ ◎ ○ ◎ ◎ ○ ◎

ingredient Comparative example One 2 3 4 5 6 Painting workability △ △ x △ △ △ Exterior x △ △ △ ○ ○ Adhesion △ x △ ○ ○ △ Water resistance x △ △ △ ○ ○ Weatherability △ △ x ○ △ △ Chemical resistance white gas △ x △ ○ ○ △ Industrial acetone △ △ x ○ ○ △ Heat resistance △ x △ ○ △ ○ Hardness x △ △ △ △ ○

As shown in Table 3, the base coating compositions of Examples 1 and 10 had excellent coating workability, and the coating films prepared therefrom had excellent durability properties such as appearance characteristics, adhesion, water resistance, and weather resistance.

On the other hand, as shown in Table 4, it can be seen that the base coating compositions of Comparative Examples 1 to 6 had insufficient coating workability or poor physical properties (adhesiveness, water resistance, weather resistance, and appearance characteristics) of the coating films prepared therefrom. there was.

Claims (6)

Base coat composition comprising polyester polyol, acrylic polyol, cellulose acetate butyrate, metal paste and solvent. The method according to claim 1,
The polyester polyol has a hydroxyl value of 100 to 150 mgKOH/g, and an acid value of 0.1 to 5 mgKOH/g, base coat composition. The method according to claim 1,
The acrylic polyol has a hydroxyl value of 20 to 100 mgKOH/g, a viscosity at 25°C of 30 to 100 cPs, and an average particle size of 100 to 500 nm, base coat composition. The method according to claim 1,
The cellulose acetate butyrate has a number average molecular weight of 10,000 to 50,000 g/mol, a butyl group content of 30 to 50% by weight, and an acetyl group content of 10 to 30% by weight, based on the total weight. The method according to claim 1,
The metal paste comprises at least one metal selected from the group consisting of silver, zinc, copper, gold, nickel and titanium, the base coat composition. The method according to claim 1,
The base coat composition comprises 20 to 40 parts by weight of polyester polyol, 5 to 20 parts by weight of acrylic polyol, 5 to 30 parts by weight of cellulose acetate butyrate, 5 to 15 parts by weight of metal paste and 10 to 35 parts by weight of solvent, base Coat composition.