WO2017200228A1 - Transparent paint composition - Google Patents

Abstract

The present invention provides a two-liquid type, oil-soluble, transparent paint composition comprising: a resin composition including an acrylic polyol resin, a polyester polyol resin, and a solvent; and a curing agent, wherein the acrylic polyol resin includes a first acrylic polyol resin and a second acrylic polyol resin, the first acrylic polyol resin having a solids content of 60 to 66 wt%, a hydroxyl value of 80 to 100 mg KOH/g, and a glass transition temperature of 20 to 40, and the second acrylic polyol resin having a solids content of 70 to 80 wt%, a hydroxyl value of 120 to 160 mg KOH/g, and a glass transition temperature of 0 to 20. The two-liquid type, oil-soluble, transparent paint composition according to the present invention not only has excellent paintability, but can provide a coat of paint having excellent physical properties in terms of external appearance, adhesiveness, water resistance, compatibility with high-pressure car washing, weather resistance and the like.

Description

Transparent Paint Composition

The present invention relates to a transparent coating composition for automobile bumpers, and more particularly, to an oil-soluble transparent coating composition which is excellent in coating film properties and appearance, and has excellent coating properties such as hardness, water resistance and weather resistance.

In recent years, the emission control policy on volatile organic compounds (VOCs) has become a very important issue for automotive paints in terms of environmental conservation and workplace improvement. As a countermeasure taken for VOC reduction in the said automobile paint, use of water-soluble paint or oil-soluble high solid paint is proposed.

Accordingly, Korean Patent No. 10-0558086 discloses a high solid transparent paint having high dryness and excellent acid resistance and scratch resistance by applying a low viscosity high solid acrylic resin.

On the other hand, in the case of paints for automobile bumpers, the coating proceeds with a multilayer coating consisting of a primer-base-transparent coating layer. In the case of the double transparent coating layer, the coating film dryness decreases when painting with a water-soluble coating in the robot coating line. Due to problems in painting workability, oil-soluble transparent coatings are being applied, and development of oil-soluble high-solids transparent coatings that can enhance the appearance and appearance of coatings is required.

The present invention is to provide a two-component oil-soluble transparent coating composition that can realize coating properties such as excellent hardness and water resistance and excellent hardness, water resistance and weather resistance.

In another aspect, the present invention is to provide an automotive part comprising a transparent paint layer formed using the two-component oil-soluble transparent paint composition.

The present invention is a two-component oil-soluble transparent coating composition comprising a resin composition comprising an acrylic polyol resin, a polyester polyol resin and a solvent and a curing agent, wherein the acrylic polyol resin has a solid content of 60 to 66 wt% and a hydroxyl value of 80 to 100 mgKOH / g, and a first acrylic polyol resin having a glass transition temperature (Tg) of 20 to 40, a solid content of 70 to 80 wt%, a hydroxyl value of 120 to 160 mgKOH / g, and a glass transition temperature (Tg) of 0 to 20 Provided is a two-part oil-soluble transparent coating composition containing a two acrylic polyol resin.

In one embodiment of the present invention, the first acrylic polyol resin and the second acrylic polyol resin may be included in a weight ratio of 1: 3 to 1: 7.

In one embodiment of the present invention, the acrylic polyol resin may be included in 40 to 70% by weight relative to the total resin composition.

In one embodiment of the present invention, the polyester polyol resin may include a polyester polyol resin having a solid content of 50 to 70% by weight and a hydroxyl value of 120 to 180 mgKOH / g.

In one embodiment of the present invention, the polyester polyol resin may be included in 10 to 35% by weight relative to the total resin composition.

In one embodiment of the present invention, the resin composition may further include an additive.

In one embodiment of the present invention, the additive may include a polysiloxane-based surface modifier and a non-silicone-based surface modifier.

In one embodiment of the present invention, the solvent may include an ester solvent and a ketone solvent.

On the other hand, the present invention provides an automotive part comprising a transparent paint layer formed using the two-component oil-soluble transparent paint composition.

The two-part oil-soluble transparent coating composition according to the present invention can provide a coating film excellent in physical properties such as appearance, adhesion, water resistance, high-pressure car wash resistance, weather resistance, as well as excellent painting workability.

Hereinafter, the present invention will be described in more detail.

One embodiment of the present invention is a two-component oil-soluble transparent coating composition comprising an acrylic polyol resin, a polyester polyol resin and a solvent comprising a solvent and a curing agent, wherein the acrylic polyol resin has a solid content of 60 to 66% by weight. , First acrylic polyol resin having a hydroxyl value of 80 to 100 mgKOH / g, and a glass transition temperature (Tg) of 20 to 40, a solid content of 70 to 80 wt%, a hydroxyl value of 120 to 160 mgKOH / g, and a glass transition temperature (Tg) It is related with the 2-component oil-soluble transparent coating composition containing the 2nd acrylic polyol resin which is 0-20.

In one embodiment of the present invention, the acrylic polyol resin has a solid content of 60 to 66% by weight (based on the total weight of the first acrylic polyol resin), a hydroxyl value of 80 to 100 mgKOH / g, and a glass transition temperature (Tg). ) Is 20 to 40 first acrylic polyol resin, the solid content is 70 to 80% by weight (based on the total weight of the second acrylic polyol resin), the hydroxyl value is 120 to 160 mg KOH / g, the glass transition temperature (Tg ) May include a second acrylic polyol resin having 0 to 20.

In one embodiment of the present invention, the acrylic polyol resin may include a first acrylic polyol resin and a second acrylic polyol resin in a weight ratio of 1: 3 to 1: 7.

When the weight ratio of the first acrylic polyol resin and the second acrylic polyol resin is out of the above range, the salvage property may be lowered, so that painting workability may be degraded or it may be difficult to provide excellent appearance characteristics.

Acrylic polyol resin according to an embodiment of the present invention 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, ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylic Acrylic monomers having at least one or more hydroxyl groups, such as rates, alone, mixtures thereof, or polymers thereof.

In addition, the acrylic polyol resin is an acrylic monomer having at least one hydroxyl group and styrene, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate or Mixtures thereof may be copolymerized.

The resin composition according to the exemplary embodiment of the present invention may include the acrylic polyol resin in an amount of 40 to 70 wt% with respect to the total resin composition, and specifically, may include 55 to 65 wt%. When the acrylic polyol resin is included in less than 40% by weight, the salvability of the coating film may be reduced, and when included in more than 70% by weight, the coating film appearance characteristics may be reduced.

In one embodiment of the present invention, the polyester polyol resin may include a polyester polyol resin having a solid content of 50 to 70% by weight (based on the total weight of the polyester polyol resin) and a hydroxyl value of 120 to 180 mgKOH / g. Can be.

The polyester polyol resin may be a resin produced by a condensation reaction of a glycol monomer and a monomer having an acid group. Examples of the glycol monomers include neopentyl glycol, trimethylolpropane, diethylene glycol, triethylene glycol, 1,6-hexanediol, 1,4-butanediol, 1,4-cyclohexane amethanol, and mixtures thereof. Can be. Examples of the monomer having an acid group include terephthalic acid, maleic anhydride, fumaric acid, phthalic anhydride, isophthalic acid, tetrahydrophthalic anhydride, adipic acid and mixtures thereof.

The polyester polyol resin is used to improve the appearance, curing density, adhesion, moisture resistance, impact resistance and the like of the coating film.

The resin composition according to an embodiment of the present invention may include the polyester polyol resin in an amount of 10 to 35% by weight based on the total resin composition, and specifically, may include 15 to 25% by weight. When the polyester polyol resin is included in less than 10% by weight, the appearance of the coating film may be lowered, and when included in excess of 35% by weight, the hardness of the coating film may be lowered.

In one embodiment of this invention, the said solvent is used to maintain the thickness of a coating film, and to improve coating workability. The solvent may be a nonpolar solvent such as n-heptane, toluene, xylene, petroleum compound, n-hexane; Ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, dibasic esters, 3-methoxy butyl acetate, amyl acetate, butyl glycol acetate, butyl cellosolve acetate, methyl Polar solvents such as ethyl ketone, methyl isobutyl ketone, acetone, diisobutyl ketone, isophorone and cyclohexanone; And at least one of the mixture of the nonpolar solvent and the polar solvent can be appropriately selected and used in accordance with the properties of the resin and the volatilization rate.

Specifically, the solvent may include a ketone solvent and an ester solvent.

The resin composition according to one embodiment of the present invention may contain the solvent in an amount of 10 to 30% by weight based on the total resin composition. If the solvent is contained in less than 10% by weight, it may be difficult to obtain the effect due to the use of the solvent, when contained in more than 30% by weight may reduce the adhesion and durability of the coating film.

In one embodiment of the present invention, the resin composition may further include an additive.

In one embodiment of the present invention, the resin composition is a curing accelerator (or curing catalyst) as an additive to promote the reaction of the resin (acrylic polyol resin and polyester polyol resin) and the curing agent to shorten the coating film drying and curing time It may further comprise. The curing accelerator may be selected from tetramethyl butane diamine, bicyclooctane, dibutyltin dilaurate, triethylene diamine and mixtures thereof.

The amount of the curing accelerator is not particularly limited, but may be included in an amount of 0.01 to 1.0 wt% based on the total resin composition. When the curing accelerator is included in less than 0.01% by weight, the drying properties and the coating film properties may be lowered, and when included in excess of 1.0% by weight, the appearance degradation and pot life may be shortened.

In one embodiment of the present invention, the resin composition may further include a surface adjuster as an additive to adjust the surface tension of the coating composition. As the surface modifier, an additive generally used in the coating composition to adjust the surface tension may be used. Specifically, a polysiloxane surface modifier and / or a non-silicone surface modifier may be used.

The amount of the surface modifier is not particularly limited, but may be included in an amount of 0.1 to 1.0 wt% based on the total resin composition. If the surface modifier is included in less than 0.1% by weight, the appearance may be lowered, and when included in excess of 1.0% by weight, adhesion may be lowered when repainting.

In one embodiment of the present invention, the resin composition may further include a ultraviolet absorber as an additive. The ultraviolet absorber is stronger than the chromophore of the acrylic polyol resin to inhibit the generation of radicals of the acrylic polyol resin and is effective in preventing discoloration, swelling, delamination, and loss of gloss of the acrylic polyol resin. As the ultraviolet absorber, hydroxyphenyl benzotriazole may be used.

The amount of the ultraviolet absorbent is not particularly limited, but may be included in an amount of 1 to 10% by weight based on the total resin composition. If the ultraviolet absorbent paper is included in excess of 10% by weight, a problem of cost increase may occur, and when included in less than 1% by weight, a problem of deterioration of weather resistance may occur.

In addition to the above components, the resin composition according to one embodiment of the present invention may further include an adhesion promoter and an antifoaming agent as an additive to improve the adhesion, moisture resistance, chemical resistance, and cold cycle cycle resistance of the coating film. .

In one embodiment of the present invention, the curing agent for curing the acrylic polyol resin and the polyester polyol resin reacts with the hydroxyl groups contained in the resins at room temperature or forced curing (75 ± 5 ℃, 40 to 50 minutes) can be used.

Specifically, one or more types can be selected and used among homopolymers or modified bodies of methylene diisocyanate, toluene diisocyanate and xylene diisocyanate which are excellent in curing rate, adhesion, coating hardness, heat resistance and the like. When the polyisocyanate is used, it is excellent in adhesion to various plastic molded articles, moisture resistance, coating hardness, and the like, and is relatively inexpensive in terms of economic efficiency.

In one embodiment of the present invention, the reaction ratio (NCO / OH) of the isocyanate functional group contained in the polyisocyanate curing agent and the hydroxyl group contained in the acrylic polyol resin and the polyester polyol resin may be 1.03 to 1.07. have. When the reaction ratio is lower than the above range, the coating film properties such as hardness and water resistance may be lowered. When the reaction ratio is higher than the above range, the coating film dryness may be lowered.

The curing agent may be diluted with a suitable solvent, stored in a separate container, and sufficiently stirred before use. The dilution rate at the time of dilution of the curing agent may be determined by combining the hydroxyl composition in the resin and the isocyanate functional group in the curing agent when the resin composition and the diluted curing agent are mixed to calculate the urethane reaction in equivalent weight equivalents. . Specifically, the mixing ratio of the resin composition and the diluted curing agent may be 1: 0.9 to 1: 1.2 based on the equivalent ratio. When the mixing ratio is mixed in excess of the equivalent ratio of 1: 1.2, excess isocyanate functional groups may occur, and when mixed below the equivalent ratio of 1: 0.9, the degree of curing may be reduced.

Another embodiment of the present invention relates to an automotive part, in particular an automobile bumper, comprising a transparent coating layer formed using the two-part oil-soluble transparent coating composition described above.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Experimental Examples. These Examples, Comparative Examples and Experimental Examples are for explaining the present invention, and it is obvious to those skilled in the art that the scope of the present invention is not limited thereto.

Example  1 to 4 and Comparative example  1 to 2: Preparation of Paint Composition

The resin compositions of Examples and Comparative Examples were prepared according to the compositions of Table 1 below. Specifically, after putting the first acrylic polyol resin, the second acrylic polyol resin, the polyester polyol resin into the container and mixing at a low speed using a stirrer, the ultraviolet absorber, the surface conditioner A, the surface conditioner B, the curing accelerator, and the solvent It injected | thrown-in, stirred for 30 minutes, and adjusted the viscosity to 59-65 KU using the solvent further as needed. A polyisocyanate curing agent (HDI Trimer) was then added to the mixture in a weight ratio of resin composition (topic): curing agent of 2.4: 1 to prepare a coating composition. The viscosity of the prepared coating composition was adjusted to 17-20 seconds (FORD CUP # 4) with dilution thinner.

ingredient	Example 1	Example 2	Example 3	Example 4	Comparative Example 1	Comparative Example 2
First acrylic polyol resin	11	13	15	10	59	0
2nd acrylic polyol resin	48	46	45	50	0	59
Polyester polyol resin	19	19	18	18	19	19
UV absorbers	2	2	2	2	2	2
Surface conditioner A	0.7	0.7	0.7	0.7	0.7	0.7
Surface conditioner B	0.2	0.2	0.2	0.2	0.2	0.2
Curing accelerator	0.1	0.1	0.1	0.1	0.1	0.1
solvent	19	19	19	19	19	19
Sum	100	100	100	100	100	100

1st acrylic polyol resin: 60-66 weight% of solid content, 80-100 mgKOH / g of hydroxyl number, Tg 20-40 (CRT01641, KCC company)

2nd acrylic polyol resin: 70-80 weight% of solid content, 120-160 mgKOH / g hydroxyl number, Tg 0-20 (SYNTHALAT-A TH 3227, STNTHOPOL company)

Polyester polyol resin: 50 to 70% by weight solids, 120 to 180 mgKOH / g hydroxyl number (SETAL 81462 SS-55, NUPLEX)

Surface adjuster A: Polysiloxane-based surface adjuster (BYK 310, BYK)

Surface adjuster B: Non-silicone surface adjuster (BYK 358N, BYK)

Solvent: Mixture of methyl isobutyl ketone, propylene glycol monomethyl ether acetate and butyl cellosolve acetate

UV absorber: EVERSORB 83 (EVERLIGHT CHEMICAL)

Curing accelerator: Dibutyl tin dilaurate (DBTDL)

Experimental Example : Evaluation of Appearance and Physical Properties of Coating Film

Apply a water-soluble primer (dry film thickness: 10-12 microns) on the polypropylene bumper and dry it for 40 to 4 minutes, apply a water-soluble basecoat (dry film thickness: 10-18 microns) and dry it for 80 to 6 minutes. It was left at room temperature for 10 minutes. The coating compositions (clear coats) prepared in Examples and Comparative Examples were coated thereon (dry coating thickness: 28 to 38 microns) and cured with hot air at 80 to 30 minutes to form a final coating film.

The coating workability, appearance and physical properties of the final coating film were measured as follows and evaluated according to the following evaluation criteria, and the results are shown in Table 2 below.

<Evaluation Criteria>

◎ -excellent

○ -good

△-Normal

X-defect

1) Painting workability

Two round trips of IWATA 61 guns (GUN) were applied to a 30 × 40 cm tin plate to compare the degree of atomization, the degree of smoothness, and the film swelling property of the coating composition.

2) Appearance

The degree of bubbles, foreign matters, spots, grooves and smoothness on the surface of the coating film was compared.

3) adhesion

Based on the ASTM D3359 tape adhesion test method, the degree of peeling after the tape adhesion test in 100 1 mm x 1 mm scales was observed.

4) water resistance

After coating the finished coating film in 40 thermostat for 10 days, the adhesion test and appearance evaluation were carried out.

5) High pressure car wash

The degree of peeling of the coating film was compared by spraying high pressure water at a pressure of 70 kgf at a distance of 10 cm with a prescribed high-pressure car wash tester.

6) Weather resistance

After applying an energy of 2500 kJ in a Xenon Weatherometer tester environment, the coating appearance, color difference, and adhesion were compared.

Item	Example 1	Example 2	Example 3	Example 4	Comparative Example 1	Comparative Example 2
Painting workability	◎	◎	◎	◎	△	○
Exterior	◎	◎	◎	◎	○	△
Adhesion	◎	◎	◎	◎	◎	◎
Water resistance	◎	◎	◎	◎	◎	◎
High pressure car wash	◎	◎	◎	◎	◎	◎
Weather resistance	◎	◎	◎	◎	◎	◎

As shown in Table 2, the coating film prepared using the transparent coating composition of Examples 1 to 4 according to the present invention has excellent coating workability and appearance, and durable properties such as adhesion, water resistance, high pressure car wash, and weather resistance. On the other hand, the coating film prepared using the transparent coating composition of Comparative Examples 1 and 2 had excellent durability but poor coating workability or appearance.

Having described the specific part of the present invention in detail, those skilled in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Therefore, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof.

Claims (9)

1. Resin composition containing acrylic polyol resin, polyester polyol resin, and a solvent; And a two-part oil-soluble transparent coating composition comprising a curing agent,

   The acrylic polyol resin has a solid content of 60 to 66% by weight, a hydroxyl value of 80 to 100 mgKOH / g, and a first acrylic polyol resin having a glass transition temperature of 20 to 40, a solid content of 70 to 80% by weight, and a hydroxyl value of 120 to 160. A two-component oil-soluble transparent coating composition comprising mgKOH / g and a second acrylic polyol resin having a glass transition temperature of 0 to 20.
2. The method of claim 1,

   The first acrylic polyol resin and the second acrylic polyol resin is a two-component oil-soluble transparent coating composition is included in a weight ratio of 1: 3 to 1: 7.
3. The method of claim 1,

   The acrylic polyol resin is a two-component oil-soluble transparent coating composition containing 40 to 70% by weight based on the total resin composition.
4. The method of claim 1,

   The polyester polyol resin is a two-component oil-soluble transparent coating composition comprising a polyester polyol resin having a solid content of 50 to 70% by weight and a hydroxyl value of 120 to 180 mgKOH / g.
5. The method of claim 1,

   The polyester polyol resin is a two-component oil-soluble transparent coating composition containing 10 to 35% by weight relative to the total resin composition.
6. The method of claim 1,

   The resin composition is a two-component oil-soluble transparent coating composition further comprises an additive.
7. The method of claim 6,

   The additive is a two-component oil-soluble transparent coating composition comprising at least one selected from the group consisting of a curing accelerator, a surface conditioner, a UV absorber, an adhesion promoter, and an antifoaming agent.
8. The method of claim 1,

   The solvent is a two-component oil-soluble transparent coating composition comprising an ester solvent and a ketone solvent.
9. An automotive part comprising a transparent paint layer formed using the two-part oil-soluble transparent paint composition according to any one of claims 1 to 8.