KR20100067895A - Water-soluble paint composition - Google Patents

Abstract

PURPOSE: An environment-friendly water-soluble paint composition is provided to obtain excellent workability and storage while remarkably lowering the content of volatile organic compounds and to obtain good storage stability. CONSTITUTION: A water-soluble paint composition includes mixing binder 60-80 parts by weight and color paste composition 1-70 parts by weight. The mixing binder contains a carboxyl group of 10-20 parts by weight and has a glass transition temperature of 10-30 °C. The mixing binder includes an emulsion resin, a polyurethane dispersion resin, pH adjusting agent for the mixing binder, and a fist solvent.

Description

Water-soluble paint composition {WATER-SOLUBLE PAINT COMPOSITION}

The present invention relates to a water-soluble coating composition, and more particularly, to a water-soluble basecoat coating composition which is excellent in storage stability and workability, and can significantly improve the environmental pollution problem by reducing the content of volatile organic solvents.

Recently, the deterioration of the global environment due to air pollution, global warming, ozone layer destruction, acid rain, etc. is getting worse. As a countermeasure to solve this problem, it is necessary to reduce the amount of volatile organic compounds (VOCs) used. This is an international issue, but Korea is also seeking regulatory measures to improve the atmospheric environment in the metropolitan area.

Accordingly, research on paint resins has been focused on the development of high-performance, high-functional polymers having various uses and characteristics, as well as the development of low pollution, low toxicity and resource saving paints related to environmental problems. In particular, research to reduce the content of organic solvents is particularly active. The driving force for this research is the regulation of emission of organic solvents for the purpose of environmental protection. Representative examples of the regulation of organic solvent emissions include the US Environmental Protection Agency's regulation of volatile organic substances and the German Air Purification Act (TA-Luft). The former sets guidelines based on the amount of organic solvent in the coating composition, and the latter limits the amount of organic solvent emitted from the coating composition required to coat one vehicle.

In general, automotive coating systems apply electrodeposition paint as a coat to protect the car body from corrosion, paint a midway to increase the elastic strength of the coating, paint a base coat top coat to give various colors thereon, and finally It consists of coating a creecoat to give gloss and scratch resistance. Among these, electrodeposition paints have been applied since the 1970s, and water-based paints are water-based solvents. However, midway, top coats and cree coats are volatile organic substances as solvents. The movement to aqueousize is active.

In the case of water-based paints, unlike solvent-based paints, since most solvents are composed of water, surface solidification is significantly delayed after coating, such as flow and staining. Therefore, in order to solve problems such as flow and stains in a dry coating film, an auxiliary additive such as a thickener capable of controlling thixotropy of the paint is used. However, these additives can control the flow and the metallic orientation by controlling thixotropy, but have a disadvantage of lowering the water resistance of the coating film if not used properly.

On the other hand, the VOC content of the base coat products among the automobile repair products is quite high. In general, automotive refinish paints include paints for the formation of putty, prima surfacer, basecoat, and clearcoat layers, the content of VOCs in each of these paints is as follows. Putty, which is a substance kneaded with pigments such as zinc oxide and calcium carbonate, with a high-viscosity colorant, is about 100-300 g / l, about 400-600 g / l for a prima surfer, and its base coat is 700- It is about 800 g / l and Cree coat is about 400-600 g / l. As described above, among the automobile repair products, the VOC content of the base coat product is the highest. Accordingly, in order to reduce the total VOC of automobile repair products, it is necessary to reduce the content of volatile organic solvents contained in the base coat paint.

High solidification has been attempted to reduce the VOCs contained in the basecoat paints.However, in the case of metallic paints, at least 80% of the solvent must be volatilized in the coating immediately after coating, so that excellent metallic orientation can be obtained depending on the shrinkage rate of the paints. Esau has a hard time getting a good metallic orientation. Basecoat paints, in particular, in automotive basecoat / creepercoat systems require fast drying. If the creecoat is applied without sufficiently drying the basecoat, the creecoat layer destabilizes the basecoat layer and affects appearance degradation and metallic orientation. This is because drying occurs when the base coat is solidified. Cellulose acetate butyrate may be used to speed up the drying of the basecoat, but in order to dissolve it, a large amount of solvent must be used, and thus there is a limit to the high solidification.

By reducing the oil-based basecoat paint as described above, a certain amount of VOC reduction can be achieved at a level of 650 g / L, but lowering it below has limitations due to coating properties and workability problems. Accordingly, it is required to improve various problems resulting from the aqueous coating of the base coat.

The technical problem of the present invention is to solve such a conventional problem, to provide a water-soluble basecoat coating composition excellent in workability and storage properties, good coating properties and eco-friendly while significantly lowering the VOC content. do.

In order to realize the above object of the present invention, the present invention comprises: i) an emulsion resin containing 10-20 parts by weight of a carboxyl group component and having a glass transition temperature of 10-30 ° C. and a solid content of 20-40 parts by weight; Polyurethane dispersion resins; 60 to 80 parts by weight of the mixing binder including a pH adjusting agent for the mixing binder and a first solvent; And ii) polyester resins; Pigments; Provided is a water-soluble basecoat coating composition comprising 1-70 parts by weight of a color paste composition comprising a pH adjusting agent for a paste composition and a second solvent.

Preferably, the emulsion resin is used in the range of 30-60 parts by weight, and the polyurethane dispersion resin is used in the range of 5-30 parts by weight. More preferably, the said polyurethane dispersion resin uses what is disperse | distributed to water.

The pH adjusting agent for the mixing binder and the pH adjusting agent for the paste composition may be the same or different, preferably amine, more preferably divalent amine may be used. The preferred pH range of the mixing binder is 8.0-9.0.

The first solvent and the second solvent may be the same or different, a solvent containing a hydrophilic group may be preferably used, and at least one selected from the group consisting of butyl cellosolve, acetone and alcohol is used.

The mixing binder may further include additives such as pigment dispersants, additives for rheology control, antifoaming agents, flow control agents, stabilizers, cryoprotectants, surface modifiers, and the like.

The amount of the polyester resin used in the paste composition is preferably in the range of 30 to 60 parts by weight.

In addition, the pigment used in the paste composition may be 7-15 parts by weight of a red pigment, 10-20 parts by weight of a yellow / orange pigment, 5-15 parts by weight of a blue pigment, 5-10 parts by weight of a black pigment, 45-60 Parts by weight of white pigment, 10-40 parts by weight of metallic pigments and the like are applicable.

It is preferable that the solvent used in the paste composition is included in the range of 10-40 parts by weight, and the viscosity of the color paste composition is in the range of 70-90 KU and the pH is in the range of 5.0-8.0. The color paste composition may also include unintended trace amounts of water, but this is negligible and substantially free of water.

On the other hand, the color paste composition comprises a metallic color paste composition comprising a metallic pigment and a solid paste composition comprising a black pigment, 60-80 parts by weight of a mixing binder, 30 parts by weight or less of the metallic color paste composition, The solid paste composition is to be included in the range of 40 parts by weight or less.

In this case, the metallic color paste composition comprises 30-60 parts by weight of polyester resin, 10-40 parts by weight of metallic pigment, 1-5 parts by weight of a wet dispersant, and 10-40 parts by weight of the second solvent, wherein the solid It is preferable that a paste composition consists of 30-60 weight part of polyester resins, 5-60 weight part of solid pigments, 20-40 weight part of said 2nd solvents, 1-10 weight part of a dispersing agent, and the said pH adjuster.

The volatile organic compound (VOC) of the basecoat coating composition of the present invention prepared according to the conditions as described above is adjustable to 420 g / L or less, the pH of this basecoat coating composition ranges from 7.5-8.0 to be.

The color paste composition may further include at least one additive selected from the group consisting of pigment dispersants, additives for rheology control, antifoaming agents, flow control agents, stabilizers, cryoprotectants and surface modifiers.

According to the present invention, 30-60 parts by weight of an emulsion resin containing a carboxyl group and having a glass transition temperature of 10-30 ° C. and a solid content of 20-40 parts by weight; 5-30 parts by weight of polyurethane dispersion resin; There is provided a mixing binder for a water-soluble basecoat coating composition comprising a pH adjusting agent for a mixing binder and a solvent.

In this case, the volatile organic compound (VOC) content of the mixing binder is 420 g / l or less.

In addition, according to the present invention 30-60 parts by weight of polyester resin; Pigments; There is provided a color paste composition for a water-soluble basecoat coating composition comprising a pH adjuster for a paste composition and a solvent.

Even in this case, the volatile organic compound (VOC) content of the color paste composition is 420 g / l or less.

According to the present invention as described above, by applying the water-soluble basecoat coating composition as an automobile repair product, while improving the workability and overall storage stability of the paint while reducing the amount of volatile organic compounds, It becomes possible.

Hereinafter, the present invention will be described in detail. The present invention is not intended to be limited to the disclosed forms as various modifications are possible, and should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

In the present invention, as a first component of the coating composition for the base coat, in the preparation of the mixing binder, having a carboxyl group component in the range of 10-20 parts by weight, the glass transition temperature is 10 to 30 ℃ and the solid content is 20 to 40 parts by weight Emulsion resin is used as a main component. The carboxyl group component is a component that has a significant effect on the viscosity in the water-soluble basecoat composition. The carboxyl group component in the emulsion resin is to be included 10-20 parts by weight. If the amount is greater than 20 parts by weight of the water resistance of the coated coating film is lowered, if less than 10 parts by weight of the thickening effect is reduced because of the problem that the metallic orientation is lowered during spraying and precipitation occurs during long-term storage of the paint. The amount of such emulsion resin to be used is in the range of 30 to 60 parts by weight.

In addition, the glass transition temperature of the resin is limited because if it is lower than 10 ° C, the coating film becomes soft, the drying becomes slow, and can be contaminated by tee, dust, etc. by the external environment during spray coating. On the other hand, when the glass transition temperature is higher than 30 ℃, the coating film is hard, there is a problem that the interlayer adhesion is lowered and chipping resistance is inferior. Therefore, the glass transition temperature of the resin is in the range of 10 ~ 30 ℃.

Polyurethane dispersion (PUD) resin should be used in the preparation of the mixing binder in an amount of 5 to 30 parts by weight. In the case of using the polyurethane dispersion, the surface of the coating film to be manufactured is soft and has good frictional resistance, and has the advantages of providing functions such as elasticity, flexibility, flexibility and chemical resistance, and modifying surface properties.

Conventional polyurethanes have been handled in a dispersed state in organic solvents, which not only are harmful during use, but also emit large amounts of volatile substances that cause environmental pollution. However, the polyurethane dispersion used in the present invention is characterized by improving the working environment as well as preventing environmental pollution by replacing the volatile organic solvent with water.

In the present invention, there is an effect of improving the chemical resistance and water resistance of the coating film by applying a PUD resin, but its amount is preferably in the range of 5-30 parts by weight. If the amount thereof is less than 5 parts by weight, when the water resistance is tested by impregnating water for 7 days in a hot water at 40 ° C. after forming a coating film, there is a problem that a blister occurs and the appearance and gloss are deteriorated. This is due to the problem of poor orientation and mottling in spray workability due to the reduced thickening effect.

In the present invention, the composition of the metallic and solid color paste compositions uses 30 to 60 parts by weight of a polyester resin having good compatibility with the mixing binder. At this time, the polyester resin is not only excellent dispersibility of the color pigment, but also excellent compatibility with the mixing binder is the most suitable resin to build a water-soluble basecoat intermix system. If the amount of resin used is less than 30 parts by weight during dispersion, it is difficult to have a particle diameter of 5 μm or less, and even when dispersed, particles are agglomerated during long-term storage, causing particles and thickening. On the other hand, when using more than 60 parts by weight, when the coating film is produced with a basecoat paint prepared by mixing with the mixing binder, it affects the quality of the coating film. In particular, drying is slowed, which causes contamination and deteriorates the appearance. Therefore, it is preferable to use polyester dispersion resin in the range of 30-60 weight part.

In the present invention, the color paste composition is prepared by mixing 30 to 60 parts by weight of a polyester dispersion resin and a pigment suitable for an automobile repair paint as described above. As the pigment, all pigments such as red, yellow / orange, blue, black, white and metallic can be used. When applied to this, 7-15 parts by weight of red, 10-20 parts by weight of yellow / orange, 5-15 parts by weight of blue, 5-10 parts by weight of black, 45-60 parts by weight of white, The metallic series is preferably applied in the range of 10 to 40 parts by weight.

More preferably, 10 to 40 parts by weight of the solvent and 1 to 10 parts by weight of the dispersing agent are used, and the color paste composition contains substantially no water. Since water is not included in the color paste composition, there is no problem of gas generation due to a reaction between aluminum and water, especially among pigment components, and thus, a problem of storage stability of the general aqueous basecoat paint may be solved. Of course, a very small amount of water contained in the air or a small amount of water contained in the compound used when preparing the color paste composition is included within the scope of the present invention.

The appropriate viscosity of the color paste composition according to the present invention is in the range of 70 to 90 KU. If the viscosity is lower than 70 KU, sedimentation or delamination may occur during storage. If the viscosity is higher than 90 KU, color paste may not be easily discharged and remain in the container due to poor fluidity when used in an intermix system.

In addition, it is preferable to use a solvent in the range of 10-40 weight part. If the amount thereof exceeds 40 parts by weight, the organic solvent content increases, making it difficult to adjust the VOC content of the color paste composition to 420 g / L or less. On the other hand, if the content is less than 10 parts by weight, it is difficult to disperse due to an increase in the viscosity of the composition and a problem occurs in the fluidity of the color paste.

In the present invention, a pH adjusting agent is used for pH control and neutralization of the mixing binder, preferably an amine, more preferably a divalent amine. When the paint composition is neutral, the workability and storage property of the paint are in the most suitable state. In general, water-soluble paints are weakly acidic unless neutralized with amines. If the paint is produced in this state, there is a problem of poor storage. In general, water-soluble paints are unstable in terms of storage properties compared to oil-based paints. Therefore, it is impossible to commercialize the product without neutralizing the paint. In the present invention, the pH is adjusted to 8.0-9.0 for the mixing binder and the metallic and solid color paste is maintained at the most stable state when adjusted to 5.0-8.0. For mixed paint compositions, pH 7.5-8.0 ranges are most suitable, which affects the thickening state of the paint and makes it most suitable for spray workability.

The composition of the basecoat paint comprises cosolvent as one or more solvents. In general, solvents suitable for emulsion resins and polyurethane dispersions are used and are selected according to their solubility, dilution and volatilization rate. For example, hydrophilic solvents such as butyl cellosolve, acetone, alcohol, and the like are preferably used. Such solvents, including hydrophilic groups, not only have excellent solubility in water-based paints, but also contain low VOCs. In addition, there is an advantage that the mixing is not a problem at all when mixing with the colorant.

In addition, the repair basecoat composition may include other raw materials, including resins used for pigment dispersion, and rheology control additives, antifoaming agents, rheology control agents, stabilizers, cryoprotectants, surface modifiers, etc., alone or in combination. have.

The present invention also provides an intermix system constituting the basecoat. The intermix system includes each individual multiple color dispersed at least one or more in the polyester resin. The intermix system is designed to apply a repair basecoat to any color. The intermix system has at least about 50 color compositions but may contain 80 or more colors. The construction of the intermix system comprises pigment dispersion pastes, metallic and mica pastes. Using this system can satisfy the color variety required for repair paints.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, of course, the scope of the present invention is not limited thereto.

Example 1

Prepared using 50 parts by weight of an emulsion resin, 15 parts by weight of polyurethane dispersion resin, 10 parts by weight of a thickener 10% solution, 5 parts by weight of a 10% solution of synthetic silicate, 3 parts by weight of 10% divalent amine solution and 12 parts by weight of deionized water. A water-soluble basecoat coating composition was prepared by mixing 80 parts by weight of the mixed binder, 15 parts by weight of a metallic color paste, and 5 parts by weight of a black color paste.

The metallic color paste composition comprises 40 parts by weight of polyester dispersion resin, 30 parts by weight of metallic pigment (STAPA® HYDROLAN 9157, manufactured by ECKART), 24 parts by weight of butyl cellulsolve, and wet dispersant (BYK-180, manufactured by BYK-chemie) 3 Part by weight, dimethyl ethanolamine (dimethyl ethanolamine) 3 parts by weight, black paste 50 parts by weight of polyester dispersion resin, black pigment (carbon black Raven 5000, manufacturer: Columbian Chemical Co.) 8 parts by weight, wet dispersant (BYK -184, manufacturer: BYK-chemie) 8 parts by weight, 1 part by weight of dimethylethanolamine, 33 parts by weight of butyl cellulsolve were dispersed in dynomil after stirring at 2000 rpm for 30 minutes at high speed to prepare a dispersion having a particle diameter of 1 to 5 μm.

The emulsion resin used was a resin having a solid content of 25%, a glass transition temperature of 25 ° C. and a carboxyl group content of 18. The polyurethane dispersion had a solid content of 33%, pH = 7.5, and a viscosity of 800 cps / 25 ° C. Spray viscosity of the prepared coating composition was podcup # 4 34sec / 25 ℃ and pH was 7.8.

Example 2

Prepared using 50 parts by weight of an emulsion resin, 15 parts by weight of polyurethane dispersion resin, 10 parts by weight of a thickener 10% solution, 5 parts by weight of a synthetic silicate 10% solution, 1 part by weight of 10% divalent amine solution, and 12 parts by weight of deionized water. A water-soluble basecoat coating composition was prepared by mixing 80 parts by weight of the mixing binder, 15 parts by weight of the metallic color paste composition, and 5 parts by weight of the black color paste composition.

The metallic color paste composition comprises 40 parts by weight of polyester dispersion resin, 30 parts by weight of metallic pigment (STAPA® HYDROLAN 9157, manufactured by ECKART), 24 parts by weight of butylcellulsolve, and wet dispersant (BYK-180, manufactured by BYK-chemie) 3 It is prepared by weight parts, 3 parts by weight of dimethylethanolamine, the black paste composition is 50 parts by weight of polyester dispersion resin, 8 parts by weight of black pigment (carbon black Raven 5000, Manufacturer: Columbia Chemical Co.), wet dispersant (BYK-184, Manufacturer: BYK-chemie) 8 parts by weight, 1 part by weight of dimethylethanolamine, 33 parts by weight of butyl cellosolve, and then stirred at 2000 rpm for 30 minutes at high speed to disperse with dynomil to prepare a dispersion having a particle diameter of 1 to 5 μm.

Solid content of the emulsion resin used was 25%, the glass transition temperature was 25 ℃ and the resin having a carboxyl group of 18. Solid content of the polyurethane dispersion was 33%, pH = 7.5, and the viscosity was 800 cps / 25 degreeC. Spray viscosity of the prepared water-soluble basecoat coating composition was Pod Cup # 4, 22sec / 25 ℃ and pH was 6.5.

Comparative Example 1

80 parts by weight of a mixing binder prepared with 65 parts by weight of an emulsion resin, 10 parts by weight of a thickener 10% solution, 5 parts by weight of a 10% solution of synthetic silicate, 3 parts by weight of 10% divalent amine solution, and 12 parts by weight of deionized water and a metallic color A basecoat coating composition was prepared by mixing 15 parts by weight of the paste composition and 5 parts by weight of the black color paste composition.

The metallic color paste composition comprises 40 parts by weight of polyester dispersion resin, 30 parts by weight of metallic pigment (STAPA® HYDROLAN 9157, manufactured by ECKART), 24 parts by weight of butyl cellulsolve, and wet dispersant (BYK-180, manufactured by BYK-chemie) 3 It is prepared by weight parts, 3 parts by weight of dimethylethanolamine, the black paste composition is 50 parts by weight of polyester dispersion resin, 8 parts by weight of black pigment (carbon black Raven 5000, Manufacturer: Columbia Chemical Co.), wet dispersant (BYK-184, Manufacturer: BYK-chemie) 8 parts by weight, 1 part by weight of dimethylethanolamine, 33 parts by weight of butyl cerusolve, followed by high-speed stirring at 2000 rpm for 30 minutes to disperse with dynomil to prepare a dispersion having a particle diameter of 1-5 μm.

The emulsion resin used was a resin having a solid content of 25%, a glass transition temperature of 25 ° C. and a carboxyl group content of 18. Spray viscosity of the prepared basecoat coating composition was Pod Cup # 4 31 sec / 25 ℃ and pH was 7.8.

Comparative Example 2

Prepared using 50 parts by weight of an emulsion resin, 15 parts by weight of polyurethane dispersion resin, 10 parts by weight of a thickener 10% solution, 5 parts by weight of a synthetic silicate 10% solution, 3 parts by weight of 10% divalent amine solution, and 12 parts by weight of deionized water. The basecoat coating composition was prepared by mixing 80 parts by weight of the mixing binder, 15 parts by weight of the metallic color paste composition, and 5 parts by weight of the black color paste composition.

The metallic color paste composition comprises 40 parts by weight of polyester dispersion resin, 30 parts by weight of metallic pigment (STAPA® HYDROLAN 9157, manufactured by ECKART), 24 parts by weight of butyl cellulsolve, and wet dispersant (BYK-180, manufactured by BYK-chemie) 3 It is prepared by weight parts, dimethylethanolamine 3 parts by weight, the black paste is 50 parts by weight of polyester dispersion resin, 8 parts by weight of black pigment (carbon black Raven 5000, Columbian Chemical Co.), wet dispersant (BYK-184, manufacturer : BYK-chemie) 8 parts by weight, 1 part by weight of dimethylethanolamine and 33 parts by weight of butyl cellulsolve were dispersed in dinomil after 30 minutes of high speed stirring to prepare a dispersion having a particle diameter of 1 to 5 μm.

The emulsion resin used was 25% solids, a glass transition temperature of 35 DEG C and a carboxyl group content of 19. Solid content of the polyurethane dispersion was 33%, pH = 7.5, and the viscosity was 800 cps / 25 degreeC. Spray viscosity of the prepared basecoat coating composition was Pod Cup # 4 36sec / 25 ℃ and pH was 7.8.

Comparative Example 3

50 parts by weight of emulsion resin, 15 parts by weight of polyurethane dispersion resin, 10 parts by weight of thickener 10% solution, 5 parts by weight of 10% solution of synthetic silicate, 3 parts by weight of 10% divalent amine solution, 12 parts by weight of deionized water A basecoat coating composition was prepared by mixing 80 parts by weight of the prepared mixing binder, 15 parts by weight of a metallic color paste composition, and 5 parts by weight of a black color paste composition.

The metallic color paste composition comprises 40 parts by weight of polyester dispersion resin, 30 parts by weight of metallic pigment (STAPA® HYDROLAN 9157, manufactured by ECKART), 24 parts by weight of butylcellulsolve, and wet dispersant (BYK-180, manufactured by BYK-chemie) 3 It is prepared by weight parts, dimethylethanolamine 3 parts by weight, the black paste is 50 parts by weight of polyester dispersion resin, 8 parts by weight of black pigment (carbon black Raven 5000, Columbian Chemical Co.), wet dispersant (BYK-184, manufacturer : BYK-chemie) 8 parts by weight, 1 part by weight of dimethylethanolamine and 33 parts by weight of butyl cellulsolve were dispersed in dinomil after 30 minutes of high speed stirring to prepare a dispersion having a particle diameter of 1 to 5 μm.

Solid content of the emulsion resin used was 25%, the glass transition temperature was 5 ℃ and the resin having a carboxyl group content of 25. Solid content of polyurethane dispersion is 33%, pH = 7.5, and viscosity is 800 cps / 25 degreeC. The spray viscosity of the prepared basecoat coating composition was Podcup # 4 at 33 sec / 25 ° C. and a pH of 7.8.

Comparative Example 4

Commonly used oil-based base coat products. 80 parts by weight of mixing binder BC-1000, 15 parts by weight metallic color paste H-941, and 5 parts by weight solid black paste in the Haikyu basecoat (manufacturer: NORU PAINT) intermix system. To produce a basecoat coating composition.

100 parts by weight of the prepared oily base coat color paint and 80 parts by weight of thinner DR-421S for basecoat were mixed and diluted to prepare a composition having a mixed spray viscosity of 13 sec / 25 ° C. with a Pod Cup # 4.

Physical property evaluation of coating film

The basecoat coating compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 4 were tested for physical properties in the following manners, and the results are shown in Table 1 below.

The procedure for preparing the test specimens was applied on a zinc phosphate-treated steel sheet and applied with Dipiai's PRIMA SURFACEA PS-330, ground with 800 sheets of abrasive paper, and washed with a car cleaner DR-180. The basecoat coating composition prepared above was twice with a dry film thickness of 8-15 μm according to a relative humidity of 60%, a temperature of 23 ° C., and a wind speed of 0.6 m / s in accordance with 2.5 bar of HVLP Sata Jet 3000 1.3mm gun. It was painted. After giving a set for 20 minutes to paint a master cream in the Dipiai Cree coat product was prepared by heat treatment for 30 minutes in an 80 ℃ drying furnace. The physical properties of the prepared coating film were evaluated.

The property evaluation method of the coating film specimen is as follows.

1) VOC: After adjusting to the sprayable viscosity, 1-3g of sample was taken, and the solid content was measured after heating at 110 ° C for 1 hour and measured by the method specified in ASTM D3960-98.

2) Tack Drying: A glass plate was applied at 76 μm and dried at 20 ° C. at room temperature.

3) Room temperature storage: It was stored for 7 days in a V-shaped test tube to measure the precipitation and precipitation state, viscosity and appearance.

4) Thermal stability: After changing for 3 days in a 50 ℃ oven was confirmed the change of state of the paint.

5) Gloss: Gloss after basecoat coating, clearcoat coating, and heat treatment was measured.

6) Adhesion: Cut out at intervals of 2 mm with cross cuts, and then test three times with cellulose adhesive.

7) Impact resistance: 500g of a weight of 30cm was dropped at a room temperature of 20 ° C to measure the degree of damage of the coating film.

8) Immersion Resistance: Immersion in a thermostatic bath at 40 ° C. for 7 days was used to measure the surface state and adhesion of the coating film.

9) Metal Stain: The color difference ΔE and ΔL values were determined by giving a fresh off time between coatings for 10 minutes and two times without coating the base coat paint.

TABLE 1

Coating property evaluation result

TABLE 2

Coating property evaluation result

In Examples 1 and 2 and Comparative Examples 1 to 3, the physical properties of the emulsion resin, which is the main component resin of the present invention, the presence or absence of the use of the polyurethane dispersion resin, the pH change, etc. were compared and examined. In the case of 4, the physical properties of the conventional oil-based basecoat coating composition were compared and examined.

In the case of Example 1 which satisfies all the preferred conditions of the present invention showed good results in all physical properties. In the case of Example 2, the pH of the prepared paint composition was slightly lower, so that the result was disadvantageous in terms of thermal stability, but in all other physical properties, it was confirmed that the result was not very unreasonable to apply as a paint. .

In Comparative Example 1, since the water resistance was poor due to the use of the polyurethane dispersion, which is the main component of the present invention, the occurrence of the brister was caused. In Comparative Example 2, the glass transition temperature of the emulsion resin used was too high. Adhesion and immersion resistance were detrimental. In Comparative Example 3, an emulsion resin component having a glass transition temperature of too low was slightly disadvantageous in terms of dry touch and poor thermal stability and immersion resistance. Comparing with the physical properties of the conventional oil-based basecoat coating composition it can be seen that the coating composition according to the embodiment of the present invention exhibits a significantly reduced effect, while showing a generally good properties in all respects. As a result, the coating composition according to the present invention exhibits environmentally friendly characteristics while providing an equivalent quality or higher in workability and physical properties compared to the oil-based basecoat composition.

In general, the water-soluble basecoat coating composition contains water as compared to the conventional oil paint, and thus, in the case of a metallic color paint, there is a problem in that storage stability is lowered due to the reaction of aluminum and water. In order to solve this problem, the color paste composition does not contain water and solves the problem of storage by water by mixing with a mixing binder containing water when used.

In addition, the present invention provides a coating composition suitable for the basecoat / creepercoat system that solves the degradation of metallic orientation, dryness, and adhesion caused by water solubility for very low VOC content.

According to the present invention, by using a mixing binder and a high concentration colorant, there is no difficulty in realizing color and excellent in storageability. In addition, since the water-soluble coating composition has a relatively long drying time compared to the oil-based paint, there is a problem that causes a cost increase by raising the temperature for forced drying or by increasing the waiting time for the subsequent process, in the present invention To solve the problem to improve the dryness of the composition to be applied to shorten the drying time of the entire coating to reduce the overall cost.

Although the foregoing detailed description of the invention has been described with reference to the preferred embodiments of the invention, those skilled in the art or those skilled in the art from the spirit and scope of the invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope thereof.

The present invention relates to a water-soluble basecoat coating composition, which is an environmentally friendly composition because of its very low VOC content, and has industrial applicability in the field of automotive repair products.

Claims (19)

i) an emulsion resin containing 10-20 parts by weight of a carboxyl group component and having a glass transition temperature of 10-30 ° C. and a solid content of 20-40 parts by weight; Polyurethane dispersion resins; 60 to 80 parts by weight of the mixing binder including a pH adjusting agent for the mixing binder and a first solvent; And ii) polyester resins; Pigments; A water-soluble basecoat coating composition comprising 1 to 70 parts by weight of a color paste composition comprising a pH adjusting agent for a paste composition and a second solvent. The water-soluble basecoat coating composition according to claim 1, wherein 30 to 60 parts by weight of the emulsion resin and 5 to 30 parts by weight of the polyurethane dispersion resin are used. The water-soluble basecoat coating composition according to claim 1, wherein the polyurethane dispersion resin is a resin dispersed in water. The water-soluble basecoat coating composition of claim 1, wherein the pH adjusting agent for the mixing binder and the pH adjusting agent for the paste composition may be the same or different and are amines. The water-soluble basecoat coating composition of claim 1, wherein the pH of the mixing binder is in the range of 8.0-9.0. The water-soluble basecoat coating composition of claim 1, wherein the first solvent and the second solvent may be the same or different, and are used in the range of 10-40 parts by weight as including a hydrophilic group. The method of claim 1, wherein the mixing binder further comprises at least one additive selected from the group consisting of pigment dispersants, additives for rheology control, antifoaming agents, flow control agents, stabilizers, cryoprotectants and surface modifiers. Basecoat paint composition. According to claim 1, wherein the polyester resin is included 30-60 parts by weight, the pigment is 7-15 parts by weight of a red pigment, 10-20 parts by weight of a yellow / orange pigment, 5-15 parts by weight of a blue pigment And 5-10 parts by weight of a black pigment, 45-60 parts by weight of a white pigment, and 10-40 parts by weight of a metallic pigment, including at least one pigment selected from the group consisting of water-soluble basecoat coating compositions. The water-soluble basecoat coating composition of claim 1, wherein the viscosity of the color paste composition is in the range of 70-90 KU. The water-soluble basecoat coating composition of claim 1, wherein the pH of the color paste composition is in the range of 5.0-8.0. The water-soluble basecoat coating composition according to claim 1, wherein the color paste composition is substantially free of water. The method of claim 1, wherein the color paste composition comprises a metallic color paste composition comprising a metallic pigment and a solid paste composition comprising a black pigment, wherein the metallic color paste composition is 30 parts by weight or less, and the solid paste composition 40 Water-soluble basecoat coating composition, characterized in that the range of parts by weight or less. The method of claim 12, wherein the metallic color paste composition comprises 30-60 parts by weight of polyester resin, 10-40 parts by weight of metallic pigment, 1-5 parts by weight of a wet dispersant, and 10-40 parts by weight of the second solvent. The solid paste composition comprises 30-60 parts by weight of a polyester resin, 5-60 parts by weight of a solid pigment, 20-40 parts by weight of the second solvent, 1-10 parts by weight of a dispersant, and the pH adjusting agent. A water-soluble basecoat coating composition. The water-soluble basecoat coating composition of claim 1, wherein the coating composition has a volatile organic compound (VOC) content of 420 g / l or less. The water-soluble basecoat coating composition of claim 1, wherein the basecoat coating composition has a pH in the range of 7.5-8.0. 30-60 parts by weight of an emulsion resin containing 10-20 parts by weight of a carboxyl group component and having a glass transition temperature of 10-30 ° C. and a solid content of 20-40 parts by weight; 5-30 parts by weight of polyurethane dispersion resin; A mixing binder for a water-soluble basecoat coating composition comprising a pH adjusting agent for a mixing binder and a solvent. 17. The mixing binder of claim 16 wherein the volatile organic compound (VOC) content of the mixing binder is 420 g / l or less. 30 to 60 parts by weight of polyester resin; Pigments; Color paste composition for water-soluble basecoat coating compositions containing a pH adjuster for paste compositions, and a solvent. 19. The color paste composition of claim 18, wherein the color paste composition has a volatile organic compound (VOC) content of 420 g / l or less.