KR101247132B1 - Water-soluble and antibiotic paint composition for plastics and method of manufacturing coating film using the same - Google Patents

Abstract

An antimicrobial aqueous coating composition for plastic parts is disclosed. 5-30% by weight of water-dispersible polyurethane resin with hydroxyl group, 10-50% by weight of water-dispersible polyurethane resin, 1-20% by weight of curing agent, 0.1-5% by weight of wetting agent, 0.1-2% by weight of antifoaming agent, 0.5-% by weight stabilizer 5 wt%, 0.01-2 wt% curing accelerator, 0.1-3 wt% thickener, 0.15-0.5 wt% antibacterial agent, 0.1-20 wt% matting agent, 0.1-5 wt% pigment, and 2-50 wt% solvent Is done. It is not only environmentally friendly and can achieve appearance, quality and reliability similar to oil-based paints, but also has excellent antibacterial properties.

Description

Antimicrobial water-based coating composition for plastic parts and method of forming coating film using the same {WATER-SOLUBLE AND ANTIBIOTIC PAINT COMPOSITION FOR PLASTICS AND METHOD OF MANUFACTURING COATING FILM USING THE SAME}

The present invention relates to an antimicrobial aqueous coating composition for plastic parts and a method of forming a coating film using the same, and in particular, to an antimicrobial aqueous coating composition for plastic parts and a method for forming a coating film using the same, which are excellent in coating properties and environmentally safe. will be.

Plastics are thought to be difficult to deteriorate by microorganisms, but may be degraded by microorganisms when additives used in processing become nutrients to microorganisms or when contaminants attached to plastic surfaces become nutrients to microorganisms.

Due to the generalization of plastics, the encapsulation of residential environments, and the optimization of room temperature, products that have antimicrobial properties are being developed in the plastics sector in response to the reality that an environment that matches microbial growth conditions is being developed, and commercial production is increasing. . In particular, the interest in hygiene has recently increased, and various methods for preventing contamination by bacteria have been applied to plastics.

In the case of plastics used for automobile interior materials, the instrument panel, door trims, center facia panel, center console, and audio panel come in contact with human body. Foreign material may adhere to the part surface. Therefore, these parts can be a breeding ground for bacteria, especially in cars where humidity and temperature are kept at an appropriate level, and can cause illness or unpleasant odors for the driver.

On the other hand, organic solvents contained in oil-based paints generate volatile organic compounds, causing environmental pollution, smells bad, and harms the health of workers. Attempts are being made to reduce the amount of organic solvents in accordance with environmental protection programs in developed countries.

Accordingly, various aqueous coating compositions for plastic materials manufactured using aqueous solvents instead of oily solvents have been studied. In order to apply the aqueous solvent to the plastic parts for automobiles, a coating composition having more excellent properties than the physical properties required for general plastics is required. Therefore, it is necessary to develop a coating composition that can be applied to various plastic materials as an aqueous coating and realize the sustainability of antibacterial activity.

Therefore, the technical problem of the present invention is not only environmentally friendly and low generation of odor and volatile organic compounds, but also can realize the same appearance, quality and reliability as conventional oil-based paints, as well as excellent antibacterial activity and antimicrobial for automobile plastic parts that can increase its durability. It is to provide an aqueous coating composition.

Another object of the present invention is to provide a method for forming an antimicrobial coating film using the above-described aqueous coating composition for automobile plastic parts.

The antimicrobial water-based coating composition for plastic parts for realizing the above object of the present invention is 5-30% by weight of water-dispersible polyurethane resin with hydroxyl group, 10-50% by weight of water-dispersed polyurethane resin, 1-20% by weight of hardener, 0.1 to 5 wt% wetting agent, 0.1 to 2 wt% antifoaming agent, 0.5 to 5 wt% light stabilizer, 0.01 to 2 wt% curing accelerator, 0.1 to 3 wt% thickener, 0.15 to 0.5 wt% antibacterial agent, 0.1 to 20 wt% %, 0.1-5 weight% of pigments, and 2-50 weight% of solvents.

In one embodiment, the water-dispersible polyurethane resin having a hydroxyl group is a) an isocyanate having an average number of functional groups of two or more, b) a hydrophilic polyol having an average number of two or more functional groups and c) polycarbonate diols and polyesterdiols It includes.

In one embodiment, the water-dispersible polyurethane resin having a hydroxyl group is 5 to 30% by weight of the isocyanate, 2 to 10% by weight of the hydrophilic polyol, 30 to 60% by weight of the polycarbonate diol and polyesterdiol, solvent 5 ~ 25 weight percent and 1-5 weight percent neutralizing agent.

In one embodiment, the water dispersion polyurethane resin has a pH of 6 ~ 10, a tensile strength of 5 ~ 35 mPa, elongation at break is in the range of 600 ~ 800%.

In one embodiment, the water-dispersed polyurethane resin is prepared by reacting at least one polyol and isocyanate selected from the group consisting of acrylic polyol, polyester polyol and polycarbonate polyol.

In one embodiment, the curing agent is at least one of isophorone diisocyanate and hydrophilic hexamethylene diisocyanate.

In one embodiment, the antimicrobial agent comprises 0.1-80 wt% of diatomaceous earth, 0.1-80 wt% of sodium oxide, 0.1-80 wt% of silver oxide, and 0.1-80 wt% of alumina.

In one embodiment, the matting agent is a micronized silica dispersion having an average particle diameter of about 1 to 30 μm.

Another object of the present invention described above is 5 to 30% by weight of a water-dispersible polyurethane resin having a hydroxyl group on a plastic material for automobiles, 10 to 50% by weight of a water-dispersible polyurethane resin, 1 to 20% by weight of a curing agent, and 0.1 to 5 wetting agent. Weight%, antifoam 0.1-2% by weight, light stabilizer 0.5-5% by weight, curing accelerator 0.01-2% by weight, thickener 0.1-3% by weight, antibacterial 0.15-0.5% by weight, quencher 0.1-20% by weight, pigment 0.1 Applying an antimicrobial aqueous coating composition for plastic parts comprising -5% by weight and 2-50% by weight of a solvent; and drying the applied coating composition.

The coating composition according to the embodiment of the present invention is environmentally friendly, generates little odors and volatile organic compounds, and has excellent antimicrobial activity while being able to realize excellent coating properties such as adhesion, water resistance, heat resistance, and the like of an oil paint. Applying such a coating composition to a plastic material can produce a high value-added product.

Hereinafter, the present invention will be described in more detail. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are further described in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In this application, the terms "comprises" or "having" are intended to indicate that there is a feature, ingredient, step, process, composition, or combination thereof described on the specification, one or more other features or ingredients, It is to be understood that it does not preclude the presence or possibility of addition of steps, processes, compositions or combinations thereof.

Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, the present invention will be described in detail.

The antimicrobial water-based coating composition for plastic parts according to the embodiment of the present invention is 5-30% by weight of the water-dispersible polyurethane resin having a hydroxyl group, 10-50% by weight of the water-dispersed polyurethane resin, 1-20% by weight of the curing agent, and 0.1∼wetting agent. 5 wt%, antifoam 0.1-2 wt%, light stabilizer 0.5-5 wt%, curing accelerator 0.01-2 wt%, thickener 0.1-3 wt%, antibacterial 0.15-0.5 wt%, quencher 0.1-20 wt%, pigment 0.1 to 5 wt% and 2 to 50 wt% solvent.

According to an embodiment, the aqueous coating composition including the antimicrobial agent exhibits an antimicrobial effect even after the coating is applied on a material and dried. The antimicrobial agent used according to the embodiment has excellent compatibility with the hydrophilic resin and dispersibility, and is evenly dispersed in the composition to prepare a form that is easy to apply to the object. In addition, after using for a long time, the carrying capacity of the antimicrobial component of the coating film is excellent, preventing the phenomenon that the antimicrobial component is gradually released and disappeared. This can result in a sustained antimicrobial effect for a long time of about 36 months or more from the time the composition is applied.

Since the formed coating film forms an antimicrobial coating film, it can prevent a variety of bacteria, fungi, viruses, etc., as well as provide a healthy and pleasant environment by removing the odor generated by the decomposition of organic matter. In addition, the coating film formed is excellent in the adhesion and adhesion to the material exhibits a continuous antimicrobial effect unless an external force is applied. Even when an external force is applied, the coating film formed is excellent in adhesion and wear resistance, so that the loss of the coating film due to factors such as friction and scratches is small.

The kind and role of each component constituting the coating composition according to the embodiment will be described in more detail.

<Water Dispersible Polyurethane Resin with Hydroxyl Group>

The amount of the water-dispersible polyurethane resin having a hydroxyl group in preparing the coating composition is in the range of about 5 to 30% by weight based on the total amount of the composition. This is because if the amount is less than about 5% by weight of the coating film properties such as adhesion, solvent resistance, etc. is a problem occurs, and if the amount is more than about 30% by weight of the coating film becomes hard, causing a decrease in texture and odor, etc. Because there is a problem.

The water-dispersible polyurethane resin having a hydroxyl group may comprise a) isocyanates having at least two average functional groups b) hydrophilic polyols having at least two average functional groups and c) polycarbonate diols and polyester diols. Specifically, the water-dispersible polyurethane resin is about 5 to 30% by weight of isocyanate, about 2 to 10% by weight of hydrophilic polyol, about 30 to 60% by weight of polycarbonate diol and polyester diol, about 5 to 25% by weight of solvent and neutralizing agent About 1 to 5 weight percent.

The specific example of each component which comprises the water-dispersible polyurethane resin which has the said hydroxyl group is demonstrated. First, a) toluene diisocyanate, 4,4-diphenyl methane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexyl methane diisocyanate and derived therefrom as an isocyanate having two or more average functional groups Preference is given to using at least one member selected from polyfunctional isocyanates. More preferably, at least one selected from isophorone diisocyanate and dicyclohexyl methane diisocyanate is used.

The isocyanate is preferably used in an amount of about 5 to 30% by weight based on the total weight of the water-dispersible polyurethane resin having a hydroxyl group, wherein a) the amount of isocyanate having an average number of functional groups of 2 or more is about 5 If it is less than the weight% may cause a problem that the mechanical properties and chemical resistance is lowered, if it exceeds about 30% by weight it may be a problem that difficult to synthesize due to high viscosity may be used within the above range.

The hydrophilic polyol having an average number of functional groups of 2 or more plays a role of dispersing water by imparting hydrophilicity to the urethane chain, and containing carboxyl groups in dimethylpropionic acid, dimethylbutanoic acid, polyoxyethylene glycol, and side chains. At least one selected from among polycaprolactone diol, polyether diol having a sulfonic acid group in the side chain, and polyol having a polyoxyethylene group substituted with an alkoxy group in the side chain can be used.

The hydrophilic polyol is preferably used in an amount of about 2 to 10% by weight based on the total weight of the water-dispersible polyurethane resin having a hydroxyl group, wherein b) the hydrophilic polyol is less than about 2% by weight. It may be insufficient to cause a problem of not being dispersed, and if it exceeds about 10% by weight may cause a problem of lowering the water resistance is good to use within the above range.

C) As the polycarbonate diol and the polyester diol, it is advantageous in terms of chemical resistance and productivity to use a diol having a weight average molecular weight range of about 500 to 2,000. The amount of the polycarbonate diol and polyester diol is preferably used in the range of about 30 to 60% by weight based on the total amount of the water dispersible polyurethane resin having a hydroxyl group.

The solvent may be a general solvent, preferably at least one selected from N-methylpyrrolidone and acetone. The solvent is preferably to use about 5 to 25% by weight relative to the total weight of the water-dispersible polyurethane resin having a hydroxyl group, if used outside the above range may be difficult to manufacture or take a long time to dry when used as a coating agent have.

In addition, as said neutralizing agent, N-methyl diethanolamine, a triethanolamine, etc. can be used, Preferably it is good to use a triethanolamine. The amount of the neutralizing agent is preferably used in about 1 to 5% by weight, the use of the neutralizing agent is insufficient when used in less than about 1% by weight, when used in excess of about 5% by weight may cause a problem of odor and discoloration It may be used within the above range because it can.

<Water Dispersion Polyurethane Resin>

The water-dispersed polyurethane resin can be synthesized by reacting polyol and isocyanate. As a polyol used for manufacture of the said water-dispersed polyurethane resin, an acrylic polyol, polyester polyol, polycarbonate polyol, etc. are mentioned. In addition, the water-dispersed polyurethane resin preferably has a pH of 6 to 10, a tensile strength of 5 to 35 mPa, and an elongation at break of 600 to 800%.

The amount of the water-dispersed polyurethane resin used in preparing the coating composition is in the range of about 10 to 50% by weight based on the total amount of the coating composition. If the amount thereof is less than about 10% by weight, there is a problem of deterioration of coating properties such as adhesion and solvent resistance, and if the amount thereof is more than about 50% by weight, the coating film becomes hard to cause texture degradation and odor. There is.

<Curing agent>

The hardening agent added for curing the coating composition is preferably isophorone diisocyanate and hydrophilic hexamethylene diisocyanate which are excellent in yellowing and weather resistance, and preferably included in the range of about 1 to 20% by weight based on the coating composition. If the content is less than about 1% by weight, there is a problem that it is difficult to secure the properties of the coating film because hardening of the paint does not occur.If the content exceeds about 20% by weight, the pot life is shortened due to the excessive amount of hardener. This can cause problems.

<Wetting agent>

Material wettability is basically determined by the difference between the surface tension of the paint and the surface tension of the workpiece. The general rule is that the paint surface tension must be at least equal to or less than the surface tension of the subject. If the paint does not spread or adhere well to the painted surface of the subject, the surface tension of the paint is higher than the surface tension of the subject. In particular, water-based water-based paints generally have a very high surface tension and thus often cause material wettability.

In order to greatly reduce the surface tension of the paint to improve the material wettability, to prevent crater phenomena, and to provide slip property on the surface, polyether modified siloxane, polyether siloxane copolymer, polydimethyl siloxane, polyether modified polydimethyl siloxane, etc. This is preferably used. The amount used is preferably included in the range of about 0.1 to 5% by weight based on the coating composition. If the content is less than about 0.1% by weight, a problem of poor appearance due to dust on the paint surface occurs, and if the content exceeds about 5% by weight, it may cause a problem of deterioration of adhesion during repainting.

<Defoamer>

It is undesirable that bubbles exist in the paint. If bubbles are generated during the production process of the paint, it is impossible to contain the optimum amount when packing the paint, and a bigger problem is that bubbles are generated when the paint is applied to generate surface defects. Bubbles not only look good, but also have the problem of deteriorating the inherent performance of the paint having a protective function. Defoamers are therefore one of the essential ingredients in the manufacture of almost all paints.

It is preferable to use a non-silicone antifoaming agent, and it is preferable to include it in the range of about 0.1 to 2 weight% with respect to the coating composition. If the content thereof is less than about 0.1% by weight, the defoaming effect is insufficient, and if it exceeds about 2% by weight it may cause a problem of deterioration of adhesion during repainting.

<Light stabilizer>

The light stabilizer is effective to prevent aging, color change, etc. of the coating film generated by exposure to light for a long time, and performs UV blocking, light energy absorption and conversion, and free radical removal. UV absorbers and UV hindered amine light stabilizers, which are organic amine compounds with steric hindrance, should be mixed and used.

As the ultraviolet absorbing light stabilizer, various kinds such as benzophenone series, oxanilide series, benzotriazole series and triazine series can be used. As the organic amine light stabilizer, 4-benzoyloxy-2,2,6,6-tetramethylbiferridine, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-hydroxybenzoide Etc. can be used. Preferably, the ratio of the ultraviolet absorbing light stabilizer and the ultraviolet inhibiting amine light stabilizer light stabilizer is suitably used in a mixture of about 2: 1 by weight.

The amount of the light stabilizer to be in the range of about 0.5 to 5% by weight based on the total amount of the coating composition. If the content thereof is less than about 0.5% by weight, there is a problem that the coating film is easily yellowed and gloss is degraded over time, and when the content is more than about 5% by weight, the paint storage stability becomes unstable.

<Curing accelerator>

As the hardening accelerator, trimethylenediamine, octosan tin, dibutyltin dilaurate, lead 2-ethylhexate and the like are preferable, and it is preferable to include in the range of about 0.01 to 2% by weight based on the coating composition. If the content is less than about 0.01% by weight, the drying time is long, and the physical properties such as chemical resistance, moisture resistance, and abrasion resistance are lowered. If the content is more than about 2% by weight, the paint hardens too rapidly, resulting in coating During operation, popping occurs in the coating or shrinkage of the coating.

<Thickener>

The thickener is preferably selected from acrylic thickeners, urethane thickeners and ethylene vinyl acetate thickeners, and may be included in the range of about 0.1 to 3% by weight based on the coating composition. If the content thereof is less than about 0.1% by weight, there is a problem that the paint flows down during painting, and thus the workability is lowered. If the content is more than about 3% by weight, the storage property may be degraded and the appearance of the coating may be poor.

<Antibacterial agent>

The antimicrobial agent may be used without particular limitation, but an inorganic antimicrobial agent is preferably applied in consideration of affinity and dispersibility of the aqueous coating composition. Specifically, about 0.1-80% by weight of diatomaceous earth (purity of 99.5% by weight or more of silicon dioxide), about 0.1-80% by weight of sodium oxide, about 0.1-80% by weight of silver oxide, and about 0.1-80% by weight of alumina It is preferable to mix so that. The average particle diameter of the mixture is preferably in the range of about 5-15 μm. The amount of the antimicrobial agent added may be included in the range of about 0.15 to 0.5% by weight based on the coating composition. If the content is less than about 0.15% by weight, it is difficult to obtain a continuous antimicrobial effect. If the content is higher than about 0.5% by weight, the antimicrobial effect is excellent, but it is uneconomical and the physical properties of the coating film such as sunscreen and PVC plasticizer may be slightly reduced. Because it can.

<Quenching agent>

As the matting agent that serves to reduce or eliminate the gloss of the material, silica gel, precipitated silica, titanium dioxide and the like can be used. In particular, in the present invention, it is preferable to use a micronitized silica dispersion having an average particle diameter of about 1 to 30 µm. If the average particle diameter thereof exceeds about 30 μm, the surface of the coating film may be coarse, resulting in poor appearance and deterioration of scratchability. Therefore, it is preferable to use a dispersion having the above-described particle size range.

The matting agent containing the micronized silica dispersion having an average particle diameter of about 1 to 30 μm is preferably included in the paint composition in a range of about 1 to 20 wt%, and if the content is within the above range, the photosensitive (quenching) surface texture There is an effect to improve. The amount of quencher used is in the range of about 0.1 to 20% by weight, based on the total amount of the composition. If the content thereof is less than about 0.1% by weight, it is difficult to obtain a matting effect, and if it exceeds about 20% by weight, there is a weak problem in scratching.

<Pigment>

Pigments are selected and mixed with inorganic pigments according to the desired color. Preferably pigments selected from various pigments such as titanium dioxide, carbon black, yellow pigment, blue pigment, green pigment, and red pigment may be mixed based on the total amount of the composition. When used in the range of about 0.1 to 5% by weight. If the content thereof is less than about 0.1% by weight, there is a problem in that coloring and concealment is difficult, and when it exceeds about 5% by weight, there is a problem in adhesion between the material and the paint.

<Solvent>

Various components are applicable as the solvent, but specifically, ethyl acetate, propyl acetate, butyl acetate, ethylene glycol methyl ether, diethylene glycol methyl ether, butylene glycol methyl ether, dibutylene glycol methyl ester, propylene glycol methyl ether, di Choose from propylene glycol methyl ether, propylene glycol methyl ether acetate, etc. and mix suitably to use it in the range of about 2-50 weight% based on the total amount of the composition. When the content thereof is less than about 2% by weight, there is a problem that the surface leveling is lowered, and when the content exceeds about 50% by weight, there is a problem that may cause an odor.

The antimicrobial water-based coating composition for plastic parts according to the embodiment may further include various additives such as slip agents and anti-settling agents in addition to the various components described above. These additives are environmentally friendly, generate less odors and volatile organic compounds, achieve the same appearance, quality and reliability as conventional oil paints, and can be used in appropriate amounts within the limit to increase the effect and durability of excellent antibacterial activity.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Car plastic parts that are environmentally friendly, less odor and less volatile organic compounds produced according to each of the above examples and comparative examples, can realize the same appearance, quality and reliability as conventional oil-based paints, as well as increase the effect and durability of excellent antibacterial activity. The following tests were performed using a sample of an antimicrobial aqueous coating composition.

A primer (Norbi Chemical, WP-200 primer) was coated on a polypropylene test piece to a thickness of about 8 to 12 μm and left at room temperature for about 5 minutes, and then dried at about 80 ° C. for about 10 minutes. After leaving at room temperature for about 5 minutes, each coating composition prepared in the composition shown in Table 1 was coated with a thickness of about 20 ~ 25㎛, left for about 15 minutes at room temperature and dried at about 80 ℃ for about 30 minutes The sample was completed. Using the completed sample, various evaluation tests were performed for each of the following items.

<Antimicrobial evaluation of coating>

The antimicrobial test was carried out according to JIS Z 2801. Antimicrobial degree (bactericidal reduction value; R (bactericidal reduction rate;%)) test was performed according to JIS Z 2801: 2000. The test conditions are as follows.

1) Test strain

① Staphylococcus aureus ATCC 6538P

② Escherichia coli ATCC 8739

2) concentration and inoculation amount

CFU/mL, 0.4mL(2.0 × 10

CFU/piece)① 5.0 × 10

CFU / mL, 0.4 mL (2.0 × 10

CFU / piece)

CFU/mL, 0.4mL(3.2 × 10

CFU/piece)② 8.0 × 10

CFU / mL, 0.4 mL (3.2 × 10

CFU / piece)

3) Size of painted plastic specimen: 50 × 50 mm

4) Control: Stomacher bag

The bacteriostatic reduction value (R) was calculated according to the formula of R = log (B / C). Here, B represents the number of bacteria of the control piece after 24 hours and C represents the number of bacteria of the test piece after 24 hours.

Using the test piece, the initial antimicrobial test, moisture resistance test, light resistance test, heat cycle test and the like were performed as follows.

Initial antimicrobial test: The antimicrobial test above was carried out.

Moisture resistance test: After leaving the specimen for about 168 hours at 50 ± 2 ℃ and 95 ± 2% of relative humidity, remove it and remove surface moisture by air blow. The antimicrobial test was performed within 10 days.

Light test: under XENON ARC, irradiate until the total cumulative amount of light reaches 1050 KJ / m ² under the condition of black panel temperature 89 ± 3 ℃, ambient humidity 50 ± 5%, RH irradiance at 340 nm and remove the specimen The solution was washed with an aqueous solution, dried with air, left at room temperature for 1 hour, and then subjected to the above antimicrobial test within 10 days.

Heat-resistant cycle test: The cycle test shown in the following table was repeated three times and the antibacterial test was performed within 10 days after being left at room temperature for 1 hour.

Cycle conditions are summarized in Table 2 below.

Cycle condition 80 ± 2 ℃ × 3 hours → Room temperature × 1 hour → -40 ± 2 ℃ × 3 hours → Room temperature × 1 hour →
50 ± 2 ℃, 95 ± 2% RH × 7 hours → room temperature × 1 hour

The antimicrobial properties of the coating film were evaluated for five specimens of each composition, and the average value was taken. The results are shown in Table 3. In Table 3, Test Bacteria ① represents Staphylococcus aureus ATCC 6538P, and Test Bacteria ② represents Escherichia coli ATCC 8739.

From the results shown in Table 3, when the addition amount of the antimicrobial agent is too small as 0.1% by weight relative to the total amount of the composition, it can be confirmed that the antimicrobial activity is low, especially after the moisture resistance test.

<Film Property Evaluation>

Adhesion test at room temperature: After 11-cut cross-cuts at 2mm intervals in the horizontal and vertical directions on the specimen, the surface is cleaned with a soft brush and firmly attached with a prescribed tape of the appropriate width and length. The number of peeled coating scales was counted by pulling strongly at an angle of 90 °. Also referred to as a checker board adhesion test, the greater the number of peeling on a total of 100 checkerboard scale was evaluated as poor adhesion.

Sun Cream Resistance: Lay up two sheets of white cotton cloth of the same size on acrylic plate (50mm × 50mm) and apply 0.25g sunscreen to the front. Place the sunscreen on the coated specimen and press the acrylic plate to bring it into close contact. It is left to stand in a thermostat at 80 ± 2 ℃ for 1 hour and then taken out to remove the white cloth and acrylic plate. Leave at room temperature for about 10-15 minutes, rinse with neutral detergent and dry. The surface state of the coating film was investigated and immediately tested for adhesion.

PVC plasticizer: Laminate the same size PVC pads (equivalent to 60 wt% of plastic material) on an acrylic plate (50mm × 50mm) and place the pads on the coated specimen and apply 0.1kgf load to the acrylic plate (Painting specimens-PVC pad-acrylic plate-load order). Leave it in a thermostatic bath at 110 ± 2 ℃ for about 1 hour and remove it to remove the load, acrylic plate and PVC pad. Leave at room temperature for about 10-15 minutes, rinse with neutral detergent and dry. The surface state of the coating film was investigated and immediately tested for adhesion.

Coating properties were taken after the evaluation of the five specimens for each composition and the results are shown in Table 4.

division Room temperature
(Peeled scale) Sunscreen
(Peeled scale) PVC plasticizer
(Peeled scale) Example 1 0 0 0 Comparative Example 1 0 0 0 Comparative Example 2 0 5 0 Comparative Example 3 0 21 One

As shown in Table 3 and Table 4, when using the antimicrobial water-based coating composition for automotive plastic parts according to Example 1 can be provided with excellent antimicrobial power, various coating film properties such as room temperature adhesion, sunscreen, PVC plasticizer It can be confirmed that this is excellent. On the other hand, in Comparative Examples 2 and 3 in which the content of the resin component is less than an appropriate level, it can be confirmed that physical properties such as adhesion are not good.

As described above, according to the present invention, the antimicrobial water-based coating composition for automobile plastic parts and the method of forming the coating film using the same are environmentally friendly, generate less odor and volatile organic compounds, and achieve similar appearance, quality, and reliability as conventional oil-based paints. In addition, the antimicrobial water-based coating material for automobile plastic parts, which enhances the effect and durability of excellent antibacterial activity, can realize high added value of plastic material for automobiles.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (9)

5 to 30% by weight of water-dispersible polyurethane resin having a hydroxyl group; Water dispersion polyurethane resin 10 to 50% by weight; 1 to 20% by weight of curing agent; 0.1 to 5 wt% wetting agent; Antifoam 0.1-2% by weight; 0.5 to 5 wt% light stabilizer; 0.01 to 2 wt% of a curing accelerator; Thickener 0.1 to 3% by weight; 0.15-0.5 wt% antimicrobial agent; 0.1-20% by weight of matting agent; An antimicrobial aqueous coating composition for plastic parts comprising 0.1 to 5 wt% of a pigment and 2 to 50 wt% of a solvent. The method of claim 1, wherein the water-dispersible polyurethane resin having a hydroxyl group is a) an isocyanate having an average number of two or more functional groups, b) a hydrophilic polyol having an average number of two or more functional groups and c) a polycarbonate diol and polyester diol Coating composition comprising a. According to claim 2, wherein the water-dispersible polyurethane resin having a hydroxyl group is 5 to 30% by weight of the isocyanate, 2 to 10% by weight of the hydrophilic polyol, 30 to 60% by weight of the polycarbonate diol and polyesterdiol, solvent 5 ~ A paint composition comprising 25% by weight and 1 to 5% by weight neutralizer. The coating composition according to claim 1, wherein the water-dispersed polyurethane resin has a pH of 6 to 10, a tensile strength of 5 to 35 mPa, and an elongation at break of 600 to 800%. The coating composition according to claim 1 or 4, wherein the water-dispersed polyurethane resin is prepared by reacting at least one polyol and an isocyanate selected from the group consisting of acrylic polyols, polyester polyols and polycarbonate polyols. The coating composition according to claim 1, wherein the curing agent is at least one of isophorone diisocyanate and hydrophilic hexamethylene diisocyanate. The coating composition according to claim 1, wherein the antimicrobial agent comprises 0.1 to 80 wt% of diatomaceous earth, 0.1 to 80 wt% of sodium oxide, 0.1 to 80 wt% of silver oxide, and 0.1 to 80 wt% of alumina. The coating composition of claim 1 wherein the matting agent is a micronized silica dispersion having an average particle diameter of about 1-30 μm. 5 to 30% by weight of a water dispersible polyurethane resin having a hydroxyl group on the plastic material for automobiles; Water dispersion polyurethane resin 10 to 50% by weight; 1 to 20% by weight of curing agent; 0.1 to 5 wt% wetting agent; Antifoam 0.1-2% by weight; 0.5 to 5 wt% light stabilizer; 0.01 to 2 wt% of a curing accelerator; Thickener 0.1 to 3% by weight; 0.15-0.5 wt% antimicrobial agent; 0.1-20% by weight of matting agent; Applying an antimicrobial aqueous coating composition for plastic parts comprising 0.1 to 5 wt% of a pigment and 2 to 50 wt% of a solvent; And
Method of forming an antimicrobial coating film comprising the step of drying the applied coating composition.