KR102280617B1 - Top coat composition - Google Patents

Abstract

The present invention includes an acrylic polyol resin and a polyisocyanate curing agent, the polyisocyanate curing agent is prepared from a curing agent composition including a polyfunctional isocyanate compound, and the polyisocyanate curing agent contains the content of unreacted NCO groups based on the total weight of the curing agent (NCO %) is 10 to 30% by weight, relates to a topcoat coating composition.

Description

Coating composition for top coat {TOP COAT COMPOSITION}

The present invention relates to a coating composition for a top coat.

Among important catch phrases applied to each industry recently, eco-friendliness is materialized in the form of actively restricting the use of volatile organic compounds. In addition, as part of the above restrictions, sanctions for products containing volatile organic compounds are being added.

The volatile organic compound is a substance that easily volatilizes into the atmosphere at room temperature due to its high vapor pressure and causes air pollution. These volatile organic compounds have inherent biotoxicity and chemical reactivity, and are known to cause various types of environmental problems. there is.

As a general paint system, an epoxy-amine curing system and a polyol-isocyanate curing system using an oil-based solvent containing a volatile organic compound are widely known, but in order to increase the eco-friendliness of the paint, it is being converted to a water-based paint composition.

In this regard, Japanese Patent No. 3,376,567 (Patent Document 1) discloses a two-component aqueous coating composition comprising an acrylic copolymer prepared from an alkoxysilane group-containing vinyl monomer and polyisocyanate. However, the composition of Patent Document 1 has a problem in that the gloss and appearance characteristics of the prepared coating film are deteriorated in a short time.

Therefore, there is a need for research and development of an eco-friendly topcoat coating composition that has excellent appearance characteristics, particularly gloss, weather resistance, impact resistance, and mechanical properties such as hardness of the prepared coating film.

Japanese Patent Registration No. 3,376,567 (published on August 15, 1995)

Accordingly, the present invention provides an environmentally friendly topcoat coating composition having excellent appearance characteristics, particularly gloss, excellent mechanical properties such as weather resistance, impact resistance and hardness of the prepared coating film.

The present invention includes an acrylic polyol resin and a polyisocyanate curing agent, the polyisocyanate curing agent is prepared from a curing agent composition including a polyfunctional isocyanate compound, and the polyisocyanate curing agent contains the content of unreacted NCO groups based on the total weight of the curing agent (NCO %) is 10 to 30% by weight, to provide a topcoat coating composition.

The coating composition for top coating according to the present invention is water-soluble, eco-friendly, and has excellent storage stability of the paint, and the appearance characteristics of the coating film prepared therefrom, especially gloss, and mechanical properties such as weather resistance, impact resistance and hardness are excellent.

Hereinafter, the present invention will be described in detail.

As used herein, "(meth)acryl" means "acryl" and/or "methacrylic", and "(meth)acrylate" means "acrylate" and/or "methacrylate".

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

paint composition for top coat

The coating composition for top coating according to the present invention includes an acrylic polyol resin and a polyisocyanate curing agent.

Acrylic Polyol Resin

The acrylic polyol resin serves to control the formation of a coating film of a composition containing the same and the mechanical and chemical properties of the prepared coating film.

The acrylic polyol resin may be directly synthesized according to a known method, or a commercially available product may be used. For example, the acrylic polyol may be prepared by copolymerizing a hydroxyl group-containing acrylic monomer and an unsaturated bond-containing monomer.

In this case, the hydroxyl group-containing acrylic monomer is, for example, 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy Oxybutyl (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate and 1,6-hexanediol di (meth) acrylate ) may include one or more selected from the group consisting of acrylates.

In addition, the unsaturated bond-containing monomer is, for example, styrene, (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, butyl (meth) acrylate , may include at least one selected from the group consisting of isobutyl (meth) acrylate, (meth) acrylic acid and lauryl (meth) acrylate.

The acrylic polyol resin may have a hydroxyl value (OHv) of 100 to 200 mgKOH/g, 120 to 180 mgKOH/g, or 140 to 160 mgKOH/g. When the hydroxyl value of the acrylic polyol resin is within the above range, there is an effect of improving the weather resistance of the coating film.

The acrylic polyol resin may have an acid value (Av) of 15 to 45 mgKOH/g, 20 to 40 mgKOH/g, or 20 to 35 mgKOH/g. When the acid value of the acrylic polyol resin is within the above range, water dispersibility and storage stability of the resin composition are improved, and water resistance is improved.

The acrylic polyol resin may have a glass transition temperature (Tg) of 30 to 60 °C, 40 to 60 °C, or 45 to 60 °C. When the glass transition temperature of the acrylic polyol resin is within the above range, there is an effect of improving the coating film formation of the composition and the gloss properties of the coating film.

The acrylic polyol resin may have a solid content (NV) of 30 to 50% by weight, or 35 to 45% by weight, based on the total weight. When the solid content of the acrylic polyol resin is within the above range, storage stability of the resin and storage stability of the coating composition may be improved, and workability may be improved.

The acrylic polyol resin may have a weight average molecular weight (Mw) of 25,000 to 65,000 g/mol, or 35,000 to 55,000 g/mol, and a number average molecular weight (Mn) of 4,500 to 7,500 g/mol or 5,000 to 6,000 g/mol. When the weight average molecular weight and the number average molecular weight of the acrylic polyol resin are within the above ranges, the hardness of the paint may be excellent.

In addition, the acrylic polyol resin may be included in the composition in an amount of 30 to 60 parts by weight based on 5 to 25 parts by weight of the polyisocyanate curing agent. Specifically, the acrylic polyol resin may be included in the composition in an amount of 35 to 55 parts by weight, or 43 to 48 parts by weight based on 5 to 25 parts by weight of the polyisocyanate curing agent. When the content of the acrylic polyol resin is within the above range, there is an effect of improving adhesion and impact resistance of the coating film.

polyisocyanate curing agent

The polyisocyanate curing agent serves to cure the coating composition by crosslinking reaction with the acrylic polyol resin.

The polyisocyanate curing agent is prepared from a curing agent composition including a polyfunctional isocyanate compound. Specifically, the polyisocyanate curing agent may be prepared from a curing agent composition including a polyfunctional isocyanate compound and a compound containing an amine group.

In addition, the polyfunctional isocyanate compound may be an aliphatic compound including two or more, or two to five isocyanate groups. Specifically, the polyfunctional isocyanate compound may be at least one selected from the group consisting of linear aliphatic and alicyclic compounds including 2 to 5 isocyanate groups. Specifically, the polyfunctional isocyanate compound may include a linear aliphatic isocyanate compound including two or more isocyanate groups and an alicyclic compound including two or more isocyanate groups.

More specifically, the polyfunctional isocyanate compound may include a linear aliphatic isocyanate compound including two or more isocyanate groups and an alicyclic isocyanate compound including two or more isocyanate groups in a weight ratio of 1 to 2:1. When the weight ratio of the linear aliphatic isocyanate compound to the cycloaliphatic isocyanate compound is within the above range, adhesion and water resistance of the prepared coating film may be excellent.

Furthermore, the polyfunctional isocyanate compound is specifically, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4-methylene dicyclohexyl diisocyanate (4,4-methylene dicyclohexyl) diisocyanate), 4,4'-dicyclohexylmethane diisocyanate (HMDI), 1,4-cyclohexane diisocyanate (CHDI), and dimeryl diisocyanate (Dimeryl diisocyanate, DDI) may include at least one selected from the group consisting of.

In addition, the compound containing an amine group is, for example, ethylene diamine, propylene diamine, 2-methyl-pentane diamine-(1,5), hexane diamine-(1,6), trimethylamine, triethylamine, Tributylamine, N,N-dimethylethanolamine, N,N-dimethylpropanolamine, N,N-dipropylethanolamine, 1-dimethylamino-2-methyl-2-propanol, N-alkyl-N,N- It may include at least one selected from the group consisting of dialkanolamines, triethanolamine, cyclohexyldimethylamine, cyclohexyldiethylamine, and cyclohexylamine.

The curing agent composition may include 55 to 95 parts by weight of the polyfunctional isocyanate compound and 1 to 10 parts by weight of the amine group. Specifically, the curing agent composition may include 35 to 55 parts by weight of a linear aliphatic isocyanate compound, 20 to 40 parts by weight of an alicyclic isocyanate compound, and 1 to 10 parts by weight of a compound containing an amine group. When the content of the linear aliphatic isocyanate compound and the alicyclic isocyanate compound is within the above range, the impact resistance of the prepared coating film is improved, and when the content of the amine group-containing compound is within the above range, the water dispersion stability of the prepared polyisocyanate curing agent is improved. It has the effect of improving the gloss of the coating film by optimizing it.

Further, the polyisocyanate curing agent has a content of unreacted NCO groups (NCO%) of 10 to 30% by weight based on the total weight of the curing agent. Specifically, the polyisocyanate curing agent may have a content of unreacted NCO groups of 10 to 25% by weight, or 13 to 21% by weight, based on the total weight of the curing agent. When the NCO% of the polyisocyanate curing agent is within the above range, there is an effect of improving the weather resistance of the prepared coating film and improving the stability of the coating composition after water dispersion.

In addition, the polyisocyanate curing agent may have a weight average molecular weight (Mw) of 500 to 3,000 g/mol. Specifically, the polyisocyanate curing agent may have a weight average molecular weight of 1,000 to 3,000 g/mol, or 1,000 to 2,000 g/mol. When the weight average molecular weight of the polyisocyanate curing agent is within the above range, it is stable when dispersed in water and has a stable reactivity with the main acrylic polyol resin, thereby improving the hardness and gloss of the prepared coating film.

In addition, the polyisocyanate curing agent may be included in the composition in an amount of 5 to 25 parts by weight based on 30 to 60 parts by weight of the acrylic polyol resin. Specifically, the polyisocyanate curing agent may be included in the composition in an amount of 11 to 19 parts by weight, or 13 to 17 parts by weight based on 30 to 60 parts by weight of the acrylic polyol resin. When the content of the polyisocyanate curing agent is within the above range, there is an effect of improving water resistance of the coating film and improving stability after water dispersion.

Meanwhile, the polyisocyanate curing agent may be diluted with a solvent, stored in a separate container, and sufficiently stirred immediately before use. In this case, the solvent is not particularly limited as long as it is a conventional solvent used in the coating composition.

The hydroxyl group (OH) of the acrylic polyol resin and the isocyanate group (NCO) of the polyisocyanate curing agent may be mixed in an equivalent ratio of 1:0.6 to 1.6, or 1:0.8 to 1.4. When the equivalent ratio of the hydroxyl group and the isocyanate group is within the above range, there is an effect of improving the stability and pot life of the coating composition after the resin and the curing agent.

diluent

The top coating composition may further include one or more diluents selected from the group consisting of a solvent and water. In this case, the solvent serves to improve workability by adjusting the viscosity of the composition including the solvent, and the water serves to reduce the generation of volatile organic compounds (VOC) in the composition.

Specifically, the top coating composition may include a solvent and water.

The water may include at least one selected from the group consisting of deionized water, pure water, ultrapure water, and distilled water.

In addition, the said solvent will not specifically limit if it is a solvent compatible with water.

additive

The top coat composition may further include additives such as a thickener, an antifoaming agent, a surface control agent, a dispersing agent, a wettability control agent, a rheology control agent, and a pigment. In this case, the additives are not particularly limited as long as they are commonly used in the coating composition.

2-component

The top coating composition may be a two-component coating composition including a main part and a curing agent part. Specifically, the main part and the curing agent part may be stored in separate containers and mixed immediately before use.

In addition, the main part may include the acrylic polyol resin, a diluent, and an additive, and the curing agent part may include the polyisocyanate curing agent, a diluent, and an additive. Specifically, the main part may include the acrylic polyol resin, a diluent, an antifoaming agent, a surface conditioning agent, a dispersing agent, a wettability regulator, a rheology regulator, a pigment and an antifoaming agent, and the curing agent part may include the polyisocyanate curing agent, a diluent and a catalyst. .

The top coating composition may have a viscosity of 5 to 40 seconds at 25° C. based on Cup No. 3 . Specifically, the top coating composition may have a viscosity of 10 to 30 seconds based on the cup No. 3 at 25°C.

As described above, the coating composition for top coating according to the present invention is water-soluble, so it is eco-friendly and has excellent storage stability, and the appearance characteristics of the coating film prepared therefrom, especially gloss, and mechanical properties such as weather resistance, impact resistance and hardness are excellent. do.

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

[Example]

Preparation Example 1. Preparation of polyisocyanate curing agent

10 parts by weight of butyl acetate, 45 parts by weight of hexamethylene diisocyanate and 30 parts by weight of isophorone diisocyanate were placed in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 60°C. After completion of the temperature increase, a mixture of 2 parts by weight of cyclohexyldimethylamine, 8 parts by weight of polyethylene glycol monomethyl ether, and 5 parts by weight of butyl acetate was added dropwise for 1 hour, then the temperature was raised to 100° C., and the reaction was performed when the unreacted NCO content reached 17% by weight. to prepare a polyisocyanate curing agent.

Preparation Example 2. Preparation of polyisocyanate curing agent

12 parts by weight of butyl acetate, 48 parts by weight of hexamethylene diisocyanate and 27 parts by weight of isophorone diisocyanate were placed in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 60°C. After completion of the temperature increase, a mixed solution of 3 parts by weight of cyclohexyldimethylamine, 5 parts by weight of polyethylene glycol monomethyl ether and 5 parts by weight of butyl acetate was added dropwise for 1 hour, then the temperature was raised to 100° C., and the reaction was performed when the unreacted NCO content reached 13% by weight. to prepare a polyisocyanate curing agent.

Preparation Example 3. Preparation of polyisocyanate curing agent

8 parts by weight of butyl acetate, 39 parts by weight of hexamethylene diisocyanate and 39 parts by weight of isophorone diisocyanate were placed in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 60°C. After completion of the temperature increase, a mixture of 2 parts by weight of cyclohexyldimethylamine, 7 parts by weight of polyethylene glycol monomethyl ether, and 5 parts by weight of butyl acetate was added dropwise over 1 hour, and then the temperature was raised to 100° C., and the reaction was performed when the unreacted NCO content reached 21% by weight. to prepare a polyisocyanate curing agent.

Preparation Example 4. Preparation of polyisocyanate curing agent

10 parts by weight of butyl acetate and 75 parts by weight of hexamethylene diisocyanate were placed in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 60°C. After completion of the temperature increase, a mixture of 2 parts by weight of cyclohexyldimethylamine, 8 parts by weight of polyethylene glycol monomethyl ether, and 5 parts by weight of butyl acetate was added dropwise for 1 hour, then the temperature was raised to 100° C., and the reaction was performed when the unreacted NCO content reached 17% by weight. to prepare a polyisocyanate curing agent.

Preparation Example 5. Preparation of polyisocyanate curing agent

10 parts by weight of butyl acetate and 75 parts by weight of isophorone diisocyanate were put into a four-necked plast equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 60°C. After completion of the temperature increase, a mixture of 2 parts by weight of cyclohexyldimethylamine, 8 parts by weight of polyethylene glycol monomethyl ether, and 5 parts by weight of butyl acetate was added dropwise for 1 hour, then the temperature was raised to 100° C., and the reaction was performed when the unreacted NCO content reached 17% by weight. to prepare a polyisocyanate curing agent.

Preparation Example 6. Preparation of polyisocyanate curing agent

15 parts by weight of butyl acetate, 35 parts by weight of hexamethylene diisocyanate and 20 parts by weight of isophorone diisocyanate were placed in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 60°C. After completion of the temperature increase, a mixed solution of 10 parts by weight of cyclohexyldimethylamine, 10 parts by weight of polyethylene glycol monomethyl ether and 10 parts by weight of butyl acetate was added dropwise for 1 hour, then the temperature was raised to 100° C., and the reaction was performed when the unreacted NCO content reached 7% by weight. to prepare a polyisocyanate curing agent.

Preparation Example 7. Preparation of polyisocyanate curing agent

5 parts by weight of butyl acetate, 50 parts by weight of hexamethylene diisocyanate and 35 parts by weight of isophorone diisocyanate were placed in a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, and the temperature was raised to 60°C. After completion of the temperature increase, a mixture solution of 0.5 parts by weight of cyclohexyldimethylamine, 4.5 parts by weight of polyethylene glycol monomethyl ether and 5 parts by weight of butyl acetate was added dropwise for 1 hour, and then the temperature was raised to 100° C., and when the unreacted NCO content reached 32% by weight, the reaction to prepare a polyisocyanate curing agent.

Examples 1 to 6. Preparation of coating composition for top coating

Each component was mixed with the composition as shown in Table 1 below to prepare a paint composition for the top coat, and at this time, the equivalent ratio of the hydroxyl group of the acrylic polyol resin and the isocyanate of the curing agent was 1:1.2.

Examples 7 to 10. Preparation of coating composition for top coat

Each component was mixed with the composition as shown in Table 2 below to prepare a paint composition for the top coat, and at this time, the equivalent ratio of the hydroxyl group of the acrylic polyol resin and the isocyanate of the curing agent was 1:1.

Examples 11 to 14. Preparation of coating composition for top coat

A topcoat coating composition was prepared by mixing each component with the composition shown in Table 2 below, and at this time, the equivalent ratio of the hydroxyl group of the acrylic polyol resin and the isocyanate of the curing agent was 1:0.8.

Comparative Examples 1 to 4.

A top coating composition was prepared in the same manner as in Example 1, except that the composition as shown in Table 3 was used.

Ingredients (parts by weight) Example One 2 3 4 5 6 subject part water 8.37 10.7 8 9.8 8.37 10.7 solvent 4.3 4 3.5 4.7 4.3 4 pigment 21.3 21.3 19.7 21.2 21.3 21.3 Acrylic polyol resin1 45.2 - - 45 45.2 - Acrylic polyol resin2 - 43 - - - 43 Acrylic polyol resin3 - - 47.5 - - - surface conditioning agent 1.3 1.3 One 1.2 1.3 1.3 dispersant 3.5 3.5 3.4 3.43 3.5 3.5 wetting agent 0.4 0.4 0.4 0.32 0.4 0.4 rheology modifier 0.23 0.3 0.2 0.23 0.23 0.3 antifoam 0.4 0.5 0.3 0.42 0.4 0.5 hardener part Polyisocyanate curing agent of Preparation Example 1 15 - - 13.7 - - Polyisocyanate curing agent of Preparation Example 2 - 15 - - - - Polyisocyanate curing agent of Preparation Example 3 - - 16 - - - Polyisocyanate curing agent of Preparation Example 4 - - - - 15 - Polyisocyanate curing agent of Preparation Example 5 - - - - - 15 total amount 100 100 100 100 100 100

Ingredients (parts by weight) Example 7 8 9 10 11 12 13 14 subject part water 8.45 10.2 7.5 9.5 8.37 10.2 8.5 9.5 solvent 4.2 5 3 3.8 4.3 4 4 4.7 pigment 22 21.3 22 21.5 21.3 21.3 21 21 Acrylic polyol resin1 44 - - 45 45 - - 45.7 Acrylic polyol resin2 - 43.5 - - - 44.2 - - Acrylic polyol resin3 - - 46 - - - 46.5 - surface conditioning agent 1.5 1.3 1.2 1.2 1.3 1.1 1.2 1.2 dispersant 3.6 3.5 3.4 3.5 3.5 3 3.4 3.4 wetting agent 0.45 0.4 0.4 0.4 0.4 0.4 0.4 0.3 rheology modifier 0.3 0.3 0.2 0.23 0.23 0.3 0.2 0.1 antifoam 0.5 0.5 0.3 0.42 0.4 0.5 0.3 0.4 hardener part Polyisocyanate of Preparation Example 1
hardener 15 - - - 15.2 15 14.5 - Polyisocyanate of Preparation Example 2
hardener - - 16 14.45 - - - - Polyisocyanate of Preparation Example 3
hardener - 14 - - - - - 13.7 total amount 100 100 100 100 100 100 100 100

Ingredients (parts by weight) comparative example One 2 3 4 subject part water 8.37 8.37 8.37 10.7 solvent 4.3 4.3 4.3 4 pigment 21.3 21.3 21.3 21.3 Acrylic polyol resin1 50.2 35.2 45.2 43 surface conditioning agent 1.3 1.3 1.3 1.3 dispersant 3.5 3.5 3.5 3.5 wetting agent 0.4 0.4 0.4 0.4 rheology modifier 0.23 0.23 0.23 0.3 antifoam 0.4 0.4 0.4 0.5 hardener part Polyisocyanate curing agent of Preparation Example 6 10 - 15 - Polyisocyanate curing agent of Preparation Example 7 - 25 - 15 total amount 100 100 100 100

Hereinafter, manufacturers and product names of each component used in Examples and Comparative Examples are shown in Table 4 below.

Chemical name or physical property Manufacturer and product name water deionized water - solvent divasic ester - pigment titanium dioxide Manufacturer: CHEMOURS,
Product Name: R-902+ Acrylic polyol resin1 NV: 40 wt%, OHv: 155 gKOH/g, Av: 23 mgKOH/g, Tg: 55°C, Mw: 41,500 g/mol, Mn: 5,300 g/mol - Acrylic polyol resin2 NV: 43 wt%, OHv: 159 gKOH/g, Av: 35 mgKOH/g, Tg: 58°C, Mw: 54,500 g/mol, Mn: 5,850 g/mol - Acrylic polyol resin3 NV: 37% by weight, OHv: 141 gKOH/g, Av: 27 mgKOH/g, Tg: 46° C., Mw: 36,000 g/mol, Mn: 5,050 g/mol - Polyisocyanate curing agent of Preparation Example 1 Unreacted NCO%: 17 wt%, Mw: 1,500 g/mol, NV: 86 wt%, specific gravity: 1.09 g/cm ³ , Viscosity: 1,000 mPa·s Polyisocyanate curing agent of Preparation Example 2 Unreacted NCO%: 13% by weight, Mw: 1,350g/mol, NV: 83% by weight, specific gravity: 1.09 g/cm ³ , Viscosity: 650mPa·s Polyisocyanate curing agent of Preparation Example 3 Unreacted NCO%: 21 wt%, Mw: 1,800 g/mol, NV: 88 wt%, specific gravity: 1.10 g/cm ³ , Viscosity: 1,600 mPa·s Polyisocyanate curing agent of Preparation Example 4 Unreacted NCO%: 17 wt%, Mw: 2,100 g/mol, NV: 86 wt%, specific gravity: 1.09 g/cm ³ , Viscosity: 2,000 mPa·s Polyisocyanate curing agent of Preparation Example 5 Unreacted NCO%: 17% by weight, Mw: 650g/mol, NV: 86% by weight, specific gravity: 1.09 g/cm ³ , Viscosity: 500mPa·s Polyisocyanate curing agent of Preparation Example 6 Unreacted NCO%: 7% by weight, Mw: 1,000g/mol, NV: 75% by weight, specific gravity: 1.09 g/cm ³ , Viscosity: 900mPa·s Polyisocyanate curing agent of Preparation Example 7 Unreacted NCO%: 32 wt%, Mw: 3,000 g/mol, NV: 90 wt%, specific gravity: 1.09 g/cm ³ , Viscosity: 1,200 mPa·s surface conditioning agent - Manufacturer: BYK,
Product Name: BYKETOL AQ dispersant - Manufacturer: BYK,
Product Name: BYK-190 wetting agent - Manufacturer: BASF,
Product Name: WE3323 rheology modifier - Manufacturer: DOW,
Product Name: RM12W antifoam - Manufacturer: BASF,
Product Name: ST2400

Test Example: Characterization of the prepared coating film

The coating compositions of Examples 1 to 14 and Comparative Examples 1 to 4 were coated, dried at room temperature for 20 minutes, and cured at 60° C. for 4 hours to prepare a specimen coating film. Thereafter, the storage stability of the coating composition and the physical properties of the coating film of the specimen were measured in the following manner, and the results are shown in Tables 5 to 7.

(1) Viscosity

Viscosity at 25° C. was measured using ZahnCup No. 3.

(2) storage stability

After the coating composition was left at 60° C. for 120 hours, a coating film was formed on the specimen in the same manner as described above, and the appearance characteristics of the coating film of the specimen prepared from the coating composition after storage (hereinafter, referred to as ‘coating after storage’) were compared. .

Specifically, when there is no pinhole and cratering on the surface of the coating film after storage Excellent (◎), 2 to 5 pinholes and cratering per specimen Good (○), More than 5 and 10 or less Normal (Δ), when it occurred more than 10, it was evaluated as bad (×).

(3) Weather resistance

ΔE value was measured based on QUV-A Type 576 hours according to ISO11507.

(4) gloss

The 60° gloss of the surface of the coating film was measured with a gloss meter for the specimen coating film, and when the measured gloss was 80% or more, the gloss was excellent, and when it was 70% or more, the gloss was judged as good.

(5) hardness

The pencil hardness of the coating film of the specimen was measured using a Mitsubishi pencil. Specifically, 3B, 2B, B, HB, F, H, 2H, and 3H each of the pencils were used to measure the maximum hardness that does not damage the coating film of the specimen (3B, 2B, B, HB, F, H, 2H). , 3H: inferior ⇔ excellent).

(6) Adhesiveness

According to ASTM D3359 tape adhesion test method, after forming 25 squares of 2 mm × 2 mm (width × length) with a knife on the coating film of the specimen, test the adhesiveness of the tape on the squares and measure the degree of peeling and attach gender was evaluated.

At this time, 5B if 25 squares are 100% completely attached, 4B if the remaining squares are 95% or more and less than 100%, 3B if 85% or more and less than 95%, 2B if 65% or more and less than 85%, 35% or more and less than 65% Case 1B and less than 35% were evaluated as 0B.

(7) Impact resistance

In accordance with ASTM D2794, a 500 g weight was dropped on the coating film of the specimen from a height of 10 inches or more, and the surface of the coating film was observed to measure the maximum height at which uniformity and peeling did not occur in the coating film to evaluate the impact resistance.

(8) water resistance

The coating composition was applied to a glass plate having a size of 15 cm × 30 cm (width × length) to a thickness of 10 μm, and then cured at 40° C. for 20 minutes. After immersing the glass plate in water for 24 hours, the glass plate was taken out of the water and the degree of discoloration of the coating film was checked. At this time, the evaluation criteria are as follows.

<Evaluation criteria>

(double-circle): There is no discoloration of a coating film.

○: slight discoloration and no floating of the coating film.

(triangle|delta): The coating film floats slightly due to slight discoloration and lack of water resistance.

X: Severe lifting of the coating film or peeling of the coating film

Example One 2 3 4 5 6 viscosity 20 seconds 22 seconds 18 seconds 19 seconds 23 seconds 22 seconds storage stability ◎ ○ ○ ◎ ○ ○ Film thickness (㎛) 40 38 42 39 40 40 Weather resistance (ΔE) 0.8 1.0 0.9 0.9 1.3 1.5 Polish 85% 82% 83% 84% 78% 78% Hardness 3H 2H 2H 3H HB HB adherence 5B 4B 4B 5B 2B 2B Impact resistance (inch) 30 28 29 30 25 25 water resistance ◎ ○ ○ ◎ △ △

Example 7 8 9 10 11 12 13 14 viscosity 21 seconds 22 seconds 17 seconds 20 seconds 20 seconds 21 seconds 19 seconds 21 seconds storage stability ◎ ○ ○ ◎ ◎ ○ ○ ○ Film thickness (㎛) 39 40 37 39 40 38 39 38 Weather resistance (ΔE) 0.9 1.1 1.0 0.9 1.0 0.9 1.0 0.8 Polish 84% 80% 81% 83% 85% 81% 84% 82% Hardness 2H 2H 2H 2H 2H 2H 2H 2H adherence 4B 4B 4B 4B 4B 4B 4B 4B Impact resistance (inch) 29 27 28 30 29 28 29 27 water resistance ◎ ○ ○ ◎ ◎ ○ ○ ○

comparative example One 2 3 4 viscosity 16 seconds 33 seconds 20 seconds 28 seconds storage stability ○ △ ○ △ Film thickness (㎛) 25 35 30 35 Weather resistance (ΔE) 1.5 1.3 1.1 1.2 Polish 60% 70% 68% 76% Hardness 2B 2B HB HB adherence 0B 0B B 2B Impact resistance (inch) 12 20 18 25 water resistance X ○ △ ○

As shown in Tables 5 and 6, the top coating compositions of Examples 1 to 14 have excellent storage stability, and the coating film prepared therefrom has excellent gloss, and mechanical properties such as weather resistance, hardness, adhesion and impact resistance. This was excellent.

On the other hand, as shown in Table 7, it was found that the coating films prepared from the coating compositions of Comparative Examples 1 to 4 were inferior in storage stability, weather resistance, gloss, hardness, adhesion and weather resistance.

Claims (5)

An acrylic polyol resin and a polyisocyanate curing agent,
The polyisocyanate curing agent is prepared from a curing agent composition comprising a polyfunctional isocyanate compound and a compound containing an amine group,
The polyisocyanate curing agent has a content of unreacted NCO groups (NCO%) of 10 to 30% by weight based on the total weight of the curing agent. The method according to claim 1,
The polyisocyanate curing agent has a weight average molecular weight of 500 to 3,000 g/mol, a topcoat coating composition. The method according to claim 1,
The polyfunctional isocyanate compound comprises a linear aliphatic isocyanate compound containing two or more isocyanate groups and an alicyclic isocyanate compound containing two or more isocyanate groups in a weight ratio of 1 to 2:1. The method according to claim 1,
The acrylic polyol resin has a hydroxyl value of 100 to 200 mgKOH/g, an acid value of 15 to 45 mgKOH/g, and a glass transition temperature of 30 to 60 °C. The method according to claim 1,
The top coating composition comprises 30 to 60 parts by weight of an acrylic polyol resin and 5 to 25 parts by weight of a polyisocyanate curing agent.