KR20100043365A - Black paint for radiator grill of automobile - Google Patents

Abstract

PURPOSE: A black paint for radiator grill of automobile is provided to improve adhesive force with a primer, to increase impact absorption capacity, to ensure excellent weather resistance and chipping resistance, and to supply a radiator grill of high quality. CONSTITUTION: A black paint for radiator grill of automobile comprises 15~35 weight% main material solids consisting of acrylic polyol, polyester and modified polyester, 0.5~5 weight% two part liquid urethane hardener, 16~35 weight% pigment, 30~65 weight% organic solvent, and 1~10 weight% of at least one additive selected from the group consisting of a dispersing agent, antiprecipitating agent, surface modifier, curing accelerator, wax type additive, silicone additive and catalyst.

Description

Black paint for car radiator grille {BLACK PAINT FOR RADIATOR GRILL OF AUTOMOBILE}

The present invention relates to a black paint for automobile radiator grille, and more particularly, to a black paint for automobile radiator grille as a top coat applied after chrome plating, and excellent in weatherability and chipping resistance.

A general method of manufacturing a radiator grill is as follows.

1) injection molding a radiator grille product into a shape and shape designed using ABS resin; 2) pre-treating the surface of the radiator grill produced by the injection molding by a cleaning process and a corrosion process for enhancing adhesion; 3) immersing the radiator grille after the pretreatment process in a chromium plating bath and plating chromium over the entire surface of the radiator grille; 4) applying a primer on the chromium plating surface to increase adhesion after the chromium plating is completed; 5) applying a top coat (base coat) of the black paint on the primer to complete the radiator grill.

The black paint applied with the primer on the chrome plated surface is applied over the remaining area except for the area where the chrome plated surface is exposed. The chromium plating process of the radiator grill manufacturing process as described above is a process that must be performed in order to decorate only a part of the radiator grill with chromium. In particular, when chrome plating is performed after the coating of black paint, there is a problem that the black coating is damaged by a pretreatment process such as corrosion performed before chromium plating. Therefore, the black coating should be performed after chrome plating.

In general, ABS resin, which is widely used as a radiator grille material, has a high surface tension value and is known to be an adhesive material that can be used to coat top coats without primer in the painting process. Therefore, the front surface of the radiator grille using black paint or body paint When painting, chipping problems rarely occur. However, recently, chromium plating is performed to give the radiator grille a high-quality appearance, and unlike ABS materials, in the case of chromium plating specifications, since black paint is coated on the surface of chromium plating, the problem of chipping property due to deterioration of adhesion is frequently caused. It is happening. This chipping problem is causing an increase in the cost of consumer claims.

The chipping problem is a phenomenon in which a rock, gravel, or sand flying from a preceding vehicle hits the surface of a radiator grill while the black coating surface is damaged and peeled off, and at the same time, the chromium plating surface forming the lower layer is exposed to the outside. Say.

This chipping problem is less frequent when the radiator grille is painted with the same color as the car body or when the entire surface is black-painted using only black paint, but as mentioned above, it is frequently used in the specification of forming a black film after chrome plating. It is happening.

The black paint used in the conventional radiator grille is composed of a primer made of chlorinated polyolefin as the main resin and a top coat to determine the final appearance and color, and the primer is coated with 5 minutes of flash off time. ) And then coated with a two-component urethane top coat and heat-dried at 80 ℃ for 30 minutes.

However, in the above-described method, the chromium plating and the black coating film do not have sufficient adhesive force, so that the phenomenon of easy peeling due to external impact occurs, and thus the chipping property needs to be improved.

In the conventional coating method, the adhesion was somewhat limited by using a method of forming physical adhesion by the polarity of the chlorine group of the chlorinated polyolefin applied to the primer.

On the other hand, in order to improve chipping, polyester is modified with polyglycol or long-chain aliphatic acid or a mixture of two or more polyesters (US Pat. Nos. 4,616,054, 4,532,177, 3,565,839, and 3,565,839). 58-74349, SO 61-23650, SO 62-15147), but there was a limit in improving chipping.

The present invention is to solve the problems of the prior art as described above, it is an object of the present invention to provide a black paint for a radiator grill which is excellent in weather resistance and chipping resistance by improving the adhesion to the primer, the impact absorption is increased.

The present invention is based on the total weight of the composition, 15 to 35% by weight of the main solid content consisting of acrylic polyol, polyester and modified polyester, 0.5 to 5% by weight of the two-component urethane type curing agent, 16 to 35% by weight pigment, organic solvent 30 Black paint for automobile radiator grill containing 1 to 10% by weight of at least 65% by weight and at least one additive selected from the group consisting of dispersants, precipitation inhibitors, surface conditioners, curing accelerators, wax type additives, silicone additives and catalysts. to provide.

In addition, the present invention provides a car radiator grill including a black coating film by the black paint.

The black paint for the radiator grill of the present invention is excellent in weatherability and chipping resistance to enable the supply of high-quality radiator grill.

In addition, there is an import substitution effect on foreign paints to reduce the production cost of related products.

The present invention is based on the total weight of the composition, 15 to 35% by weight of the main solid content consisting of acrylic polyol, polyester and modified polyester, 0.5 to 5% by weight of the two-component urethane type curing agent, 16 to 35% by weight pigment, organic solvent 30 To black paint for automobile radiator grill comprising: 1 to 10% by weight of at least 65% by weight and at least one additive selected from the group consisting of dispersants, precipitation inhibitors, surface conditioners, curing accelerators, wax type additives, silicone additives and catalysts. It is about.

In the black paint of the present invention, when the content of the main solid content is less than 15% by weight, problems of adhesion and mechanical properties are lowered. When the content of the solid content exceeds 35% by weight, appearance defects, poor workability and chipping resistance may occur. do.

The main solid is composed of 13.5 to 27% by weight of acrylic polyol, 1 to 5% by weight of polyester and 0.5 to 3% by weight of modified polyester, based on the total weight of the composition.

It is more preferable that the said subject solid content is contained in 15 to 29 weight% with respect to the composition total weight.

The acrylic polyol is composed of a copolymerizable aliphatic unsaturated acid monomer, 60 to 80% by weight acrylic ester monomer, 15 to 35% by weight unsaturated monomer having a hydroxyl group and 1 to 5 unsaturated monomers based on the total weight of the acrylic resin 2 to 10 wt% of the polymerization chain transfer agent and 2 to 5 wt% of the polymerization initiator are added to the wt%, and 100 parts by weight of the acrylic resin obtained by reacting at 110 to 140 ° C. and 5 to 15 parts by weight of the liquid polycarbonate diol. . In this case, when the liquid polycarbonate diol content is less than 5 parts by weight, there is a problem in that the ductility of the coating film is insufficient and the mechanical properties are insufficient, and when it exceeds 15 parts by weight, the coating film is too flexible to cause a problem of low gloss and hardness.

The acrylic polyol has a weight average molecular weight in the range of 1500 to 5000, the glass transition temperature is preferably 25 to 65 ℃.

In the black paint of the present invention, when the acrylic polyol is contained in an amount less than 13.5% by weight based on the total weight of the composition, a problem of insufficient weather resistance and mechanical properties of the coating film may occur. It may cause the chipping property to deteriorate.

The acrylic polyol is more preferably contained in 18 to 25% by weight relative to the total weight of the composition.

The acrylic polyol used in the present invention is the main resin used with emphasis on improving weather resistance and chipping resistance of the coating film, and the characteristics of the resin are shown in Table 1 below.

 TABLE 1

division Vis. A.V N.V (%) Tg (占 폚) OH% Solvent Molecular Weight Acrylic polyol W ~ Z 5 ↓ 51 ± 1.5 55 0.65 toluene 30,000

The polyester is a carboxylic acid or derivatives thereof and derivatives capable of forming esters, and those having 1 to 10 carbon atoms. In this case, the carboxylic acid may be a functional aromatic or aliphatic carboxylic acid having 2 to 8 carbon atoms, and is particularly preferable when the carboxylic acid is bifunctional. In addition, the polyester is preferably substituted with a long-chain alkyl group of 6 to 18 carbon atoms.

The polyester is an acid component of at least one aromatic carboxylic acid and at least one aliphatic carboxylic acid, and a monoacid, monoalcohol or glycidyl substituted with at least two alkylene glycols and long-chain alkyl groups having 6 to 18 carbon atoms. As co-polyester synthesized by ester, it is preferable that glass transition temperature is about -40-20 degreeC. Properties of the polyester are shown in Table 2 below.

TABLE 2

division Hazen color value PH (KOH mg / g) Viscosity (at 23 ° C, 80% in butyi acetate (mPaS) OH% Hydroxyl content Water content Polyester ≤150 2 ± 1 2,200 ± 400 1.6 4.3 ± 0.4% ≤0.1%

In the black paint of the present invention, if the polyester is contained in less than 1% by weight based on the total weight of the composition, the problem of chipping resistance is lowered, and if it exceeds 5% by weight, poor drying, poor appearance, and lower mechanical properties .

In the present invention, the modified polyester is one modified by adding aliphatic diisocyanate, polycaprolactone polyol or polymethacrylate diol to a polyester composed of aliphatic linear carboxylic acid having 2 to 8 carbon atoms and alcohol having 1 to 10 carbon atoms. Can be used.

3 to 40 parts by weight of aliphatic diisocyanate is modified to 100 parts by weight of the polyester, and when the amount of aliphatic diisocyanate is less than 3 parts by weight, chipping resistance is lowered, and when it exceeds 40 parts by weight, appearance defects occur. do. The polycaprolactone polyol or polymethacrylate diol is used in an amount of 10 to 100 parts by weight based on 100 parts by weight of the polyester resin. If the amount is less than 10 parts by weight, the flexibility of the coating film is lowered, and a chipping problem occurs. If it exceeds, the coating film becomes too soft and the hardness falls.

The said polyester uses the thing of the number average molecular weights 1,000-3,500, and if it is less than the said range, adhesiveness falls and when it exceeds, hardness falls.

The modified polyester resin is preferably composed of 70% volatile volatile matter, OH% 1.7.

In the black paint of the present invention, when the modified polyester is included in less than 0.5% by weight based on the total weight of the composition, the problem of chipping resistance is lowered. When the modified polyester is more than 3% by weight, poor drying, poor appearance, and poor mechanical properties Triggered.

The two-component urethane type curing agent is NCO: OH is used is designed to be 1: 1, specific examples include HDI (Hexamethylene diisocyanate) trimer (Trimer).

In the black paint of the present invention, when the two-component urethane type curing agent is contained in an amount of less than 0.5% by weight based on the total weight of the composition, curing of the paint is insufficient, resulting in a contamination problem of the paint. It occurs too rapidly, causing popping or shrinkage of the coating during coating.

The black paint of this invention mixes and uses a hardening | curing agent at the time of use as a two-component paint.

The pigment is preferably composed of 15-30% by weight of the extender pigment and 1-5% by weight of the pigmented pigment based on the total weight of the composition.

As the extender pigment used to impart the durability and mechanical performance of the coating film, talc, cray, silica, aluminum hydroxide compound, etc. may be used, and it is preferable to use talc. Sieving pigments should be formulated and designed to maintain a solid coating film and prevent the decomposition of the coating film during coating. Corrosion resistance, tensile strength, shear stress, elasticity, etc. are required as an important performance of the coating film.

In the present invention, in particular, talc is used as a extender pigment so as to be blended and designed to have excellent chipping resistance of the coating film.

In the black paint of the present invention, when the extender pigment is included in an amount of less than 15% by weight based on the total weight of the composition, a problem occurs that the durability and mechanical performance of the coating film decreases. Physical properties may be reduced.

Carbon black may be used as the coloring pigment, and the pigment having a good oil absorption may be selected and verified by itself so as to facilitate dispersion during blackness and dispersion. Considering that the appearance depends on the dispersibility of the paint, the selection of carbon black pigment is an important process.

In the black paint of the present invention, when the pigment is contained in less than 1% by weight relative to the total weight of the composition, the coloring is insufficient, and the appearance of the coating is deteriorated. When the pigment is more than 5% by weight, due to waste of the pigment and insufficient content of other components The physical properties of the coating film may be lowered.

In the black paint of the present invention, organic solvents include hydrocarbon-based, ketone-based, ester-based, ether-based, and the like. A solvent having a relatively high solubility, containing about 60% or more of the solvent component, is used. Considering the boiling point, select a highly volatile solvent.

A wet dispersant may be used as a dispersant to facilitate dispersibility in dispersing the pigment in the additive, preferably 3 wt% or less based on the total weight of the composition. As the wet dispersant, a multifunctional polymer alkylol ammonium salt solution which is effective in reducing viscosity and enhancing glossiness may be preferably used. The properties of this wet dispersant are shown in Table 3 below.

[Table 3]

General Properties of Wet Dispersants Amine number mgK Acid value mgK density Solids% Flash point (° C) solvent 33 33 1.04 65 46 Methoxy propyl acetate / propylene glycol / methoxy propanol = 5/3/2

As the anti-settling agent among the additives used for the purpose of imparting a special function of the coating film, a swelling dispersant composed of a special synthetic polyamide and xylene can be used. The anti-settling agent imparts thixotropy to the oil paint to prevent the stabilization of the dispersion and the flow of the paint and to prevent the sedimentation of the pigment, it is preferably included 3% by weight or less based on the total weight of the composition. The characteristics of this anti-settling agent are shown in Table 4 below.

TABLE 4

Exterior flash point Non-ignition Specific gravity (at 20 ℃) solvent Solubility Light white light PASTE phase About 12 ℃ 15 ± 1% 0.877 Alcohol, Xylene Insoluble in water, aliphatic, aromatic when heated with heat

Among the additives, a surface modifier is used to obtain a coating film having excellent leveling during coating, and a surface modifier composed of an acrylic polymer is preferable. The content is preferably 0.5% by weight or less based on the total weight of the composition, more preferably 0.1% by weight or less. The properties of the surface modifier composed of the acrylic polymer are shown in Table 5 below.

 TABLE 5

Appearance color Non-volatile Particle Size Viscosity Acid Transparency 400 max 83.0 ± 3.0% 2.3 Y ~ Z5 (Bubble viscometer) 3 max (mgKOH / g)

Among the additives, the wax type additive is used for the purpose of preventing erosion of the coating film, improving scratch resistance, preventing blocking, and the like, and a solvent type polyethylene wax type may be used. It is used at 0.2 to 1 weight% with respect to the total weight of a non-volatile coating composition, and 0.5% is more preferable. The properties of this solvent type polyethylene wax additive are shown in Table 6 below.

 TABLE 6

division Polymer NV (%) Particle size Solvent (%) Note Wax type additives Polyethylene wax 10 2.3 Toluene 70%, ethyl acetate 20% Micro particle

Among the additives, the silicone additive is used for the purpose of improving the gloss, orange peel, and anti-silking of the coating film, and may be used in an amount of 0.01 to 0.1% by weight, preferably 0.03% by weight, based on the total weight of the non-volatile coating composition. Is good. Specific examples include dimethyl silicone oil, and the characteristics of dimethyl silicone oil are shown in Table 7 below.

 TABLE 7

division Exterior Viscosity 25 ° C (CS) Specific gravity 25 ℃ NV (%) 150 degrees Celsius * 24 hours Refractive index Silicone additives Colorless transparent liquid 20 0.95 30 or less 1.393

Since the black coating composition which consists of the composition mentioned above can be manufactured by the method normally known in this field, the manufacturing method is not specifically limited.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are provided to illustrate the present invention, and the present invention is not limited to the following examples and may be variously modified and changed.

Example 1 Preparation of Black Paint Composition

According to the composition shown in Table 9, the main resin and dispersing additives were added to the tank, the solvent was added, and then slowly stirred to make a uniform composition, and then gradually added to the pigment so that the pigment completely wetted with the resin and the solvent ( WETTING) was added to the disperser and dispersed to have a particle size of 5 μm or less. The black coating composition was manufactured by mixing a hardening | curing agent here.

TABLE 9

ingredient Content (% by weight) subject Acrylic polyol 21 Polyester 2.6 Modified polyester 1.6 Hardener Hexamethylene diisocyanate (HDI) trimer 4.5 ~ 5.5 solvent Hydrocarbon Solvent 30-38 Ester Solvent 7-14 Miscellaneous 0 ~ 2 Pigment Sieving pigment 22-24 Pigmentation Pigment 2.3 ~ 2.7 additive Sedimentation inhibitors 2.0 ~ 3.0 Surface conditioner Catalyst (tin catalyst) 0.3 ~ 0.5 Dispersant 1.5 ~ 2.5

Test Example 1 Evaluation of Physical Properties of Black Coating Film

The physical properties of the black paint for the radiator grill prepared in Example 1 were as shown in Table 8, the physical properties of the coating film formed by applying the black paint in a conventional manner is shown in Table 9.

TABLE 8

division NV (%) Viscosity (KU) importance Granularity Black Paint for Radiator Grille 53.5 ± 0.5 75 ± 10.0 1.20 ± 0.2 15 ㎛ or less

TABLE 9

Item standard result Adhesion Visual evaluation clear Moisture resistance 50 ° C, 90%, 240 hr clear Heat resistance 80 ℃, 300hr clear Chipping resistance Visual evaluation clear Water resistance 40 ℃, 240 hr clear Weather resistance 2500kJ clear Chemical resistance Engine oils, waxes, glass cleaners clear

Claims (11)

15-35 weight% of main solids which consist of acrylic polyol, polyester, and a modified polyester with respect to composition total weight, 0.5-5 weight% of hardening agents of a two-component urethane type, 16-35 weight% of pigments, and 30-65 weight of organic solvents Black paint for a car radiator grill, comprising 1% to 10% by weight of one or more additives selected from the group consisting of a dispersant, a precipitation inhibitor, a surface conditioner, a curing accelerator, a wax type additive, a silicone additive and a catalyst. The black paint for automobile radiator grill according to claim 1, wherein the main solid is composed of 13.5 to 27% by weight of acrylic polyol, 1 to 5% by weight of polyester, and 0.5 to 3% by weight of modified polyester, based on the total weight of the composition. . The method according to claim 2, wherein the acrylic polyol is polymerized chain in 60 to 80% by weight acrylic acid ester monomer, 15 to 35% by weight unsaturated monomer having a hydroxyl group and 1 to 5% by weight unsaturated monomer having an acid group based on the total weight of the acrylic polyol A vehicle comprising 100 parts by weight of an acrylic resin obtained by adding 2 to 10% by weight of a transfer agent and 2 to 5% by weight of a polymerization initiator to react at 110 to 140 ° C, and 5 to 15 parts by weight of a liquid polycarbonate diol. Black paint for radiator grilles. The black paint for automobile radiator grill according to claim 2, wherein the polyester comprises a carboxylic acid or a derivative thereof and an alcohol having 1 to 10 carbon atoms and a long chain alkyl group having 6 to 18 carbon atoms is substituted. The black paint for automobile radiator grill according to claim 4, wherein the carboxylic acid is a C2-C8 functional aromatic or aliphatic carboxylic acid. The method of claim 2, wherein the modified polyester is a polyester composed of C2-C8 aliphatic linear carboxylic acid and C1-C10 alcohol is modified with aliphatic diisocyanate, polycaprolactone polyol or polymethacrylate diol Black paint for car radiator grille, characterized in that. The black paint for automobile radiator grill of claim 1, wherein the two-component urethane type hardener is NCO: OH 1: 1. The method of claim 1, wherein the pigment is composed of 15 to 30% by weight of the extender pigment and 1 to 5% by weight of the pigment, based on the total weight of the composition, the extender pigment is talc, the coloring pigment is characterized in that the carbon black car grill Dragon black paint. The black paint for automobile radiator grill according to claim 1, wherein a multifunctional polymer alkylol ammonium salt solution is used as a dispersant in the additive. The black paint for automobile radiator grill according to claim 1, wherein a surface modifier composed of an acrylic polymer is used as the surface modifier among the additives. An automobile radiator grill comprising the black coating film of any one of claims 1 to 10.