KR101315318B1 - Coating composition for vehicle - Google Patents

Abstract

The present invention relates to a coating composition for automobiles, and more particularly to a coating composition for automobiles consisting of a blocked polyisocyanate, an acrylic resin, a surface leveling agent and a viscosity modifier.
The automotive coating composition composed of the above-mentioned components contains an acrylic resin formed with a blocked polyisocyanate and an epoxy group, and exhibits excellent appearance quality, mechanical properties and acid resistance.

Description

Automotive paint composition {COATING COMPOSITION FOR VEHICLE}

The present invention relates to a paint composition for automobiles, and more particularly to automotive coatings containing an acrylic resin formed with a blocked polyisocyanate and an epoxy group, which is suitable for use as a top coat or a transparent paint for automobiles. It relates to a composition.

The present invention relates to a paint composition for automobiles, and more particularly to automotive coatings containing an acrylic resin formed with a blocked polyisocyanate and an epoxy group, which is suitable for use as a top coat or a transparent paint for automobiles. It relates to a composition.

Cars coated with the transparent paints used in the related art have fine scratches when they are washed with an automatic washing machine, which has recently been rapidly spread, and when these scratches accumulate, the gloss of the painted surface of the car is gradually faded, which adversely affects the appearance of the car. There was a problem.

Scratch resistance is different depending on the magnitude, speed, direction of the applied force and shape, hardness, and coefficient of friction of the contacting material.If the resin skeleton is adjusted to improve scratch resistance, the hardness and chipping resistance of the coating film (CHIPPING), there was a problem that cold cracking and the like is lowered.

In addition, as well as scratch resistance, there is a problem in that damage to the coating film is aggravated when the automotive coating film is exposed to acid rain caused by the deepening air pollution.

In order to solve the above-mentioned problems, various methods for improving acid resistance in the manufacturing process of automotive transparent paints that have been recently developed have been tried. Among them, new methods include curing reactions of epoxy groups and acid groups during curing, Although curing reaction of epoxy group and anhydride and curing reaction with hydroxyl group have been attempted, such a new curing method improves acid resistance of coating film, but improves coating appearance, manufacturing cost, productivity, adhesion, storage property and yellowing property. There is a problem that is lowered, there was no effect on improving scratch resistance.

An object of the present invention is to provide a coating composition for automobiles containing polyisocyanate and acrylic resin formed with an epoxy group having excellent appearance quality, mechanical properties and acid resistance.

The object of the present invention is achieved by providing a coating composition for automobiles, characterized in that it comprises a blocked polyisocyanate, an acrylic resin, a surface leveling agent and a viscosity modifier.

According to a preferred feature of the present invention, the automotive paint composition is to be composed of 100 parts by weight of the sealed polyisocyanate, 450 to 500 parts by weight of acrylic resin, 5.5 to 6 parts by weight of the surface smoothing agent and 3 to 5 parts by weight of the viscosity modifier.

According to a further preferred feature of the invention, the blocked polyisocyanate is to be blocked with 3,5-dimethylpyrazole.

According to a more preferred feature of the invention, the acrylic resin is composed of methyl methacrylate, n-butyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate and benzoyl peroxide.

According to an even more preferred feature of the present invention, the surface leveling agent is composed of butyl acrylate, 2-ethylhexyl acrylate and dietary butyl peroxide.

According to a further preferred feature of the invention, the viscosity modifier is to be made of xylene.

The paint composition for automobiles according to the present invention contains an acrylic resin formed with a blocked polyisocyanate and an epoxy group, and has excellent appearance quality, mechanical properties and acid resistance.

Hereinafter, preferred embodiments of the present invention and physical properties of the respective components will be described in detail with reference to the accompanying drawings. However, the present invention is not limited thereto, And this does not mean that the technical idea and scope of the present invention are limited.

The paint composition for automobiles according to the present invention is composed of a blocked polyisocyanate, an acrylic resin, a surface leveling agent and a viscosity modifier, including 100 parts by weight of polyisocyanate, 450 to 500 parts by weight of acrylic resin, 5.5 to 6 parts by weight of surface smoothing agent, and More preferably, 3 to 5 parts by weight of the viscosity modifier.

The above-mentioned blocked polyisocyanate is added with 100 parts by weight, and is based on 1,6-diisocyanatohexane having an NCO content of 20 to 24%, biuret group, isocyanurate group, allophanate group, It is preferable to contain an iminooxadiazinedione group, a urethane group, and uretdione group, and the like, and the polyisocyanate reacts with the hydroxyl group formed on the acrylic resin described above to serve to provide an automotive coating composition having excellent mechanical properties. .

The above-mentioned acrylic resin is added to 450 to 500 parts by weight, and serves to provide a coating composition for automobiles having excellent mechanical properties by reacting with the above-mentioned blocked polyisocyanate, wherein the acrylic resin is methyl methacrylate, n When benzoyl peroxide, a polymerization initiator, is mixed with an acrylic monomer mixture composed of -butyl acrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate, and the benzoyl peroxide is converted into a radical by heating or ultraviolet irradiation, It is prepared by the polymerization reaction by.

The above-mentioned methacrylate is preferably added to 270 to 300 parts by weight, the above-mentioned n-butyl acrylate is preferably added to 60 to 90 parts by weight, the above-mentioned 2-hydroxyethyl methacrylate is 50 parts by weight It is preferable to add, and it is preferable to add 5 to 50 parts by weight of the aforementioned glycidyl methacrylate, wherein methyl acrylate and n-butyl acrylate are the molecular weight or glass transition temperature of the acrylic resin. It is a component generally used in consideration of the above, and the aforementioned 2-hydroxyethyl methacrylate is mixed to give a hydroxyl group to the acrylic resin, and the aforementioned glycidyl methacrylate is the main chain of the acrylic resin. 3,5-dimethylpyrazole, a blocking agent that is dissociated in the curing process by introducing an epoxy group into the acrylic resin Used to combine.

5.5 to 6 parts by weight of the above-described surface leveling agent is added, serves to block the surface defects of the coating film formed of the automotive paint composition serves to improve the appearance quality of the coating film.

Such a surface leveling agent is preferably used by mixing 70 parts by weight of butyl acrylate and 30 parts by weight of 2-ethylhexyl acrylate, and 0.1 parts by weight of dietary butyl peroxide as a polymerization initiator.

3 to 5 parts by weight of the above-described viscosity modifier is added, and serves to improve the flowability by adjusting the viscosity of the coating film formed of the automotive paint composition.

It is preferable that such a viscosity modifier consists of xylene.

Hereinafter, the production method and the physical properties of the automotive paint composition according to the present invention will be described with reference to Examples.

≪ Example 1 >

In a 3-liter round-bottomed glass flask equipped with a stirrer, nitrogen inlet, thermocouple and heater, 412 g of solvent naphtha 100, 137 g of 1-methoxypropyl acetate, BURNOCK DN-980S (about 21.5% by weight of NCO and 25 ° C) 1150 g of a solvent-free HDI trimer having a viscosity of about 28.5 Poise, available from Aekyung Chemical Co., Ltd.) were placed in a container, 560 g of solid 3,5-dimethylpyrazole was added while stirring at a temperature of 90 ° C, and the NCO group was no longer Stirred at 90 ° C. for about 1 hour until not detected, resulting in a viscosity of about 35 poice at a temperature of 23 ° C., with a content of blocked NCO of 10.4% by weight and a solid content of about 75% by weight of 3,5-dimethylpyra Polyisocyanates blocked with sol were prepared.

<Example 2>

Into a four-necked flask equipped with a stirrer, a cooler and a thermometer, 200 g of toluene and 200 g of butyl acetate were added, the internal air was replaced with nitrogen, and the temperature was raised to 110 ° C. An acrylic monomer mixture composed of 300 g of acrylate, 90 g of n-butyl acrylate, 50 g of 2-hydroxyethyl methacrylate, and 5 g of glycidyl methacrylate was added thereto, stirred for 3 hours, and then cooled to room temperature to obtain a solid content. 50% acrylic resin was prepared.

<Example 3>

Proceed in the same manner as in Example 2, an acrylic resin mixture of 298 g of methyl methacrylate, 87 g of n-butyl acrylate, 50 g of 2-hydroxyethyl methacrylate, and 10 g of glycidyl methacrylate was added thereto. Prepared.

<Example 4>

Proceed in the same manner as in Example 2, an acrylic resin mixture of 294 g of methyl methacrylate, 81 g of n-butyl acrylate, 50 g of 2-hydroxyethyl methacrylate, and 20 g of glycidyl methacrylate was added thereto. Prepared.

<Example 5>

Proceed in the same manner as in Example 2, an acrylic resin mixture of 291 g of methyl methacrylate, 75 g of n-butyl acrylate, 50 g of 2-hydroxyethyl methacrylate, and 30 g of glycidyl methacrylate was added thereto. Prepared.

<Example 6>

Proceed in the same manner as in Example 2, an acrylic resin mixture of 275 g of methyl methacrylate, 69 g of n-butyl acrylate, 50 g of 2-hydroxyethyl methacrylate, and 40 g of glycidyl methacrylate was added thereto. Prepared.

&Lt; Example 7 >

Proceed in the same manner as in Example 2, an acrylic resin mixture of 271 g of methyl methacrylate, 63 g of n-butyl acrylate, 50 g of 2-hydroxyethyl methacrylate, and 50 g of glycidyl methacrylate was added thereto. Prepared.

&Lt; Example 8 >

100 g of polyisocyanate sealed with 3,5-dimethylpyrazole prepared in Example 1 480 g of acrylic resin prepared in Example 2, 70 g of butyl acrylate and 30 g of 2-ethylhexyl acrylate and 0.1 butyl peroxide 5.8 g of the surface leveling agent prepared in grams was added to a high speed kneader, dispersed for 30 minutes at a speed of 2000 rpm, and then 4 g of xylene was added to adjust the viscosity to 60 seconds using Pod Cup No. 4, and the mixture having the viscosity adjusted to 300 Filtration was carried out with a mesh filter net to prepare an automotive paint composition.

&Lt; Example 9 >

Proceed in the same manner as in Example 8, using the acrylic resin prepared in Example 3 to prepare a paint composition for automobiles.

&Lt; Example 10 >

Proceed in the same manner as in Example 8, using the acrylic resin prepared in Example 4 to prepare a coating composition for automobiles.

<Example 11>

Proceed in the same manner as in Example 8, using the acrylic resin prepared in Example 5 to prepare a coating composition for automobiles.

&Lt; Example 12 >

Proceed in the same manner as in Example 8, using the acrylic resin prepared in Example 6 to prepare a coating composition for automobiles.

&Lt; Example 13 >

Proceed in the same manner as in Example 8, using the acrylic resin prepared in Example 7 to prepare a paint composition for automobiles.

&Lt; Comparative Example 1 &

Into a four-necked flask equipped with a stirrer, a cooler and a thermometer, 200 g of toluene and 200 g of butyl acetate were added, the internal air was replaced with nitrogen, and the temperature was raised to 110 ° C., and 60 g of benzoyl peroxide, an initiator, was charged into a four neck flask, and methyl meta An acrylic monomer mixture consisting of 300 g of acrylate, 90 g of n-butyl acrylate, and 50 g of 2-hydroxyethyl methacrylate was added thereto, stirred for 3 hours, and cooled to room temperature to prepare an acrylic resin having a solid content of 50%. .

Comparative Example 2

100 g of polyisocyanate blocked with 3,5-dimethylpyrazole prepared in Example 1 was prepared using Comparative Example 1, 480 g of acrylic resin, 70 g of butyl acrylate, 30 g of 2-ethylhexyl acrylate, and 0.1 g of dibutyl butyl peroxide. 5.8 g of the surface smoothing agent prepared in a high-speed kneader, dispersed for 30 minutes at a speed of 2000 rpm, 4 g of xylene was added to adjust the viscosity to 60 seconds with Pod Cup No. 4, and the mixture was adjusted to 300 mesh Filtration was carried out with a filter net of to prepare a paint composition for automobiles.

Automotive coating compositions prepared through the above-described Examples 8 to 13 and Comparative Example 2 by using a gravity-type air coating machine to the thickness of 20㎛ on a 200mm × 200mm size galvanized steel sheet is electrodeposited and finished the middle coating After coating to a thickness of 40 μm over a period of time, it was left for 10 minutes and cured for 25 minutes in an oven adjusted to a temperature of 150 ℃ to prepare a test specimen.

The appearance quality, gloss, coating film adhesion, cold resistance chipping resistance, impact resistance and acid resistance of the specimen prepared by the above-described method was measured and shown in Table 1 below.

{However, the appearance was visually confirmed and indicated by ○ (excellent), △ (good), × (poor), × × (poor), gloss was measured using a gloss meter.

Coating film water resistance was measured by the cross-cutting method.

The cold resistance chipping resistance was applied to a Honda Stone (diameter, 2.5 to 5 mm) at a pressure of 4 bar after 3 hours of exposure at -40 ° C to confirm peeling portions between 1 and 2 mm.

Impact resistance was measured at the height which the crack and peeling of a coating film generate | occur | produce after dropping the weight of 500g to the surface of a coating film.

Acid resistance was confirmed by visually checking the degree of damage of the coating after repeated 5 times of dropping sulfuric acid solution having a concentration of 10% on the surface of the coating with a dropper and then leaving it in an oven at 70 ° C. (Circle): No damage part, (triangle | delta): Only a trace remains, ×: Fine trace generate | occur | produces, × x: Fine trace}

TABLE 1

As shown in Table 1 above, it can be seen that the automotive paint composition prepared by the present invention has superior water resistance, cold resistance chipping resistance, and acid resistance as compared to the conventional paint composition prepared by Comparative Example.

Claims (6)

It consists of a blocked polyisocyanate, acrylic resin, surface leveling agent and viscosity control agent,
The surface smoothing agent is a coating composition for automobiles, characterized in that consisting of butyl acrylate, 2-ethylhexyl acrylate and dietary butyl peroxide.
The method according to claim 1,
The automotive paint composition is an automotive paint composition comprising 100 parts by weight of a sealed polyisocyanate, 450 to 500 parts by weight of acrylic resin, 5.5 to 6 parts by weight of surface smoothing agent and 3 to 5 parts by weight of viscosity modifier.
The method according to claim 1,
The blocked polyisocyanate is a coating composition for automobiles, characterized in that it is blocked with 3,5-dimethylpyrazole.
The method according to claim 1,
The acrylic resin is a coating composition for automobiles, characterized in that consisting of methyl methacrylate, n-butyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate and benzoyl peroxide.
delete The method according to claim 1,
The viscosity modifier is a coating composition for automobiles, characterized in that made of xylene.