JPH05194882A - Metallic coating composition - Google Patents

Abstract

PURPOSE:To provide a metallic coating compsn. capable of forming a metallic coating film having a high weatherability and a novel beauty. CONSTITUTION:The objective metallic coating compsn. comprises titanium flakes, a particulate metal oxide coated with oxide or hydroxide of at least one element selected from zirconium, aluminum and silicon, and a resin. The compsn. can be very effectively used as a top coating for cars in particular by virtue of its unique beauty and excellent weatherability.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a coating composition for protecting or decorating an object. More specifically, it relates to a metallic coating composition for forming a coating film having excellent designability and weather resistance, which is characterized by containing titanium flakes and a transparent metal oxide.

[0002]

2. Description of the Related Art Various coating compositions have been used to protect or decorate objects, but metallic coatings in particular exhibit a unique brilliance, and are therefore characterized by their designability, which makes them suitable for automobile surface coating. Is used for. For this metallic paint, flaky metal powder such as aluminum, stainless steel, and copper is used. Recently, these flaky metal powders have an average particle size of iron oxide, titanium oxide, etc. of 0.
A metallic paint having a further improved design property is used by mixing and using a particulate metal oxide having a particle size of 01 to 0.05 μm (JP-A-63-183965).

[0003]

In conventional metallic paints, aluminum, stainless steel, copper, etc. are used as metal powders, but in any case, the metal powder reacts with water, so that the ashing phenomenon of the coating film occurs. Or there was a problem in the weather resistance of the coating film. In addition, iron oxide,
A fine particle metal oxide having an average particle diameter of 0.01 to 0.1 μm such as titanium oxide is mixed with a metal powder such as aluminum or stainless steel, but this is also a problem in terms of weather resistance of the coating film. Was left.

[0004]

Means for Solving the Problems The present inventor has conducted extensive studies to develop a metallic coating composition having high weather resistance and capable of obtaining a metallic coating film having a more novel design property. Metallic coating composition comprising fine particles of metal oxide and resin coated with titanium flakes and oxides or hydroxides of one or more elements of zirconium, aluminum, silicon, and fine particles thereof We have found a metallic coating composition in which the metal oxide is rutile type particulate titanium dioxide.

The titanium flakes used in the present invention may be produced by any method, and there is no problem even if the surface of the titanium flakes is treated with a coupling agent, an organic surface treating agent such as a higher fatty acid. .. Further, the titanium flakes have an average particle size of 10 to 30 μm and an average thickness of 0.1.
0.5 μm, particle size range of 3 to 45 μm is 90% by weight or more,
Those having a shape with an aspect ratio of 20 to 300 are preferable.

When titanium flakes having an average particle diameter of less than 10 μm are used as paints, only coatings having a low metallic gloss can be obtained. On the other hand, if the average particle size exceeds 30 μm, a rough metallic coating film is formed, which is aesthetically unfavorable. In the case of titanium flakes having an average thickness of less than 0.1 μm, it is difficult to obtain flakes having a smooth surface, and when the flakes having a non-smooth surface are formed into a coating material and coated, a coating film having less metallic gloss is obtained. On the other hand, if it exceeds 0.5 μm, the coating area per flake weight is small and the hiding power is poor, which is not preferable as a paint pigment. 90% by weight in the particle size range of 3 to 45 μm
When it is less than the above, it means that fine flakes or coarse flakes are increased, and it becomes difficult to obtain a good metallic luster, and it is also difficult to obtain an aesthetically good metallic coating film. If the aspect ratio (the value obtained by dividing the average particle size of flakes by the average thickness) is less than 20, the coating area per weight is small and the hiding power is poor, and if it exceeds 300, it is difficult to economically produce.

On the other hand, the particulate metal oxides used in the present invention include titanium dioxide, iron oxide, zirconium oxide, zinc oxide, magnesium oxide, etc. These particulate metal oxides have weather resistance and pigment characteristics. In order to impart the above, it is necessary to be surface-modified with an oxide or hydroxide of one or more elements such as silicon, aluminum and zirconium, and further stearic acid, lauric acid and polyhydric alcohol. The surface may be treated with an organic substance such as.

As a preferred titanium dioxide used in the present invention, rutile type titanium dioxide particles having a particle surface of Z
0.5 to 8.0 wt% (TiO ₂ basis) of zirconium oxide in terms of rO ₂ and 1.0 to ₄ in terms of Al ₂ O _3.
Rutile-type fine particle titanium dioxide or rutile-type fine particle dioxide coated with an aluminum oxide in an amount of 0.0% by weight (based on TiO ₂ ) and having an average particle size of 0.01 to 0.07 μm and having high weather resistance and high light discoloration resistance. The surface of titanium particles is converted into ZrO ₂ in an amount of 0.5 to 8.0% by weight (based on TiO ₂ ) zirconium oxide and Al ₂ O ₃ in an amount of 1.0 to 40.
0% by weight (based on TiO ₂ ) of aluminum oxide is coated, and 0.5 to 5.0% by weight (Ti) calculated as ZrO ₂ on the zirconium oxide and aluminum oxide.
O ₂ standard) hydrated oxide of zirconium is deposited, and 1.0 to 10.0 wt% (TiO ₂ standard) hydrated oxide of aluminum is further deposited thereon in terms of Al ₂ O _3. A rutile type fine particle titanium dioxide having an average particle diameter of 0.01 to 0.07 μm and having high weather resistance and high light discoloration resistance is preferable.

The average particle size of the fine particle titanium dioxide is 0.0
If it is less than 1 μm, the effect of highlighting and flop gloss of the coating film cannot be exhibited, and the dispersibility in paint etc. becomes poor. Is not preferable because it is damaged. The reason why aluminum and zirconium are treated with an oxide is to improve the weather resistance and light discoloration resistance of fine particle titanium dioxide. ZrO ₂ is less than 0.5% by weight and Al ₂ O ₃ is 1.0% by weight.
If it is less than wt%, improvement in weather resistance and light discoloration resistance cannot be obtained. On the other hand, ZrO ₂ exceeds 8.0% by weight, and Al ₂
When O ₃ exceeds 40.0% by weight, further improvement in weather resistance and light discoloration resistance cannot be obtained. Further, the effect of highlighting and flop gloss of the coating film cannot be sufficiently exhibited.

The treatment with the oxide of aluminum and zirconium and the further treatment with the hydroxide of aluminum and zirconium further improve the weather resistance and the light discoloration resistance and the dispersibility of the fine particle titanium dioxide. This is because zirconium hydroxide has a ZrO ₂ content of 0.1.
If it is less than 5% by weight and the amount of aluminum hydroxide as Al ₂ O ₃ is less than 1.0% by weight, improvement in weather resistance, light discoloration resistance and dispersibility cannot be obtained. On the other hand, when zirconium hydroxide exceeds 5.0% by weight as ZrO ₂ and aluminum hydroxide exceeds 10.0% by weight as Al ₂ O ₃ , weather resistance, light discoloration resistance and dispersibility are obtained. Further improvement of Further, the effect of highlighting and flop gloss of the coating film cannot be sufficiently exhibited.

As a preferred blending ratio of the above raw materials of the present invention, titanium flakes are blended in an amount of 1 to 10 parts by weight per 100 parts by weight of the metallic coating composition of the present invention, and finely divided metal oxides are metallic coating materials of the present invention. 0.3 to 20 parts by weight is blended per 100 parts by weight of the composition, and the weight ratio of fine particle metal oxide / titanium flakes is 0.3 to.
It is preferably blended in the metallic coating composition at a ratio of 2.0. Here, if the content of titanium flakes is less than 1 part by weight, the brilliance of the coating film is not sufficient, while if it exceeds 10 parts by weight, the physical properties of the coating film deteriorate, which is not preferable. Further, if the weight ratio of the particulate metal oxide / titanium flakes is less than 0.3, an aesthetically pleasing coating film cannot be obtained.
If the ratio exceeds 0, the aesthetics are not improved so much and it is not economical.

Further, the resin used in the present invention includes, but is not limited to, acrylic resin, acrylic melamine resin, alkyd resin, polyurethane resin, polyester resin, amino resin and the like. Usually, such a resin is used in an amount of 30 to 6 per 100 parts by weight of the coating composition.
It is preferably used in such a proportion that it occupies 0 part by weight of solid content. If the solid content is less than 30 parts by weight, an aesthetically pleasing coating film cannot be obtained, and durability will be a problem. On the other hand, if it exceeds 60 parts by weight, workability at the time of coating will be impaired and the durability of the coating film will not be economically improved.

Solvents used for dissolving such resin or for dispersing titanium flakes and fine particulate metal oxide in such resin are toluene, xylene,
Examples include common solvents such as butyl cellosolve and ethyl acetate. Further, a stabilizer, an organic ultraviolet absorber, an antioxidant and the like may be added to the metallic coating composition of the present invention as required. Furthermore, there is no problem even if an organic pigment such as quinacridone or carbon black is mixed.

The general procedure for making the metallic coating compositions and coatings of the present invention is described below. First, the particulate metal oxide is dispersed in a resin solution diluted with a solvent. As the disperser used here, a sand grinder using beads, a dyno mill, or the like is used. After this, a resin and / or a solvent is added to obtain the desired pigment concentration. Next, titanium flakes made into a paste with an organic solvent are dispersed in the solvent, a resin solution diluted with the solvent is added, and after uniformly mixing, a resin and / or a solvent is added to obtain a desired concentration, and a titanium flake-containing coating material is added. To create. The predetermined amounts of the particulate metal oxide-containing coating material and the titanium flake-containing coating material thus prepared are mixed, and a solvent is added if necessary to adjust the viscosity. The metallic coating composition thus created,
A metallic coating film is formed by applying the composition by spray coating, roll coating or the like on a substrate such as a metal plate or ceramics that has been electrodeposition-coated and / or intermediate-coated, and then drying and baking. In addition, a clear coating consisting of a resin and a solvent is applied on the coating thus formed or the coating before baking to form a two-layer coating consisting of a metallic coating and a clear coating. You can also

[0015]

EXAMPLES The present invention will be specifically described with reference to the following examples. Examples 1 to 3 Blended particulate titanium dioxide coating particulate titanium dioxide MT-500HD 25.0 g (Taika Co., Ltd., Zr, Al oxide treated brand) Acrylic resin 47-712 40.0 g (NV50%, Dainippon Ink and Chemicals) Chemical Industry Co., Ltd.) Mixed solvent 60.0 g (toluene / xylene / ethyl acetate = 5/2/2 (weight ratio)) The above mixture was weighed in a 400 cc mayonnaise bottle and adjusted to 0.
After throwing in 500 g of 8 mmφ alumina beads and dispersing with a paint shaker for 2 hours, acrylic resin 47-712 40.0 g melamine resin L-117 16.7 g (NV 60%, Dainippon Ink and Chemicals, Inc.) mixing Solvent (same as above) 16.0 g Resin solution having the above blending ratio was added, and after further mixing for 10 minutes, 50.0 g of mixed solvent was added and mixing was continued for 2 to 3 minutes.

Blended Titanium Flake Paint Titanium Flake Paste M-350 60.0 g (NV 70%, Showa Aluminum Powder Co., Ltd.) Mixed solvent (same as above) 135.0 g Weigh the above blend into a 400 cc mayonnaise bottle. After stirring with a disper at a low rotation speed for 10 minutes, acrylic resin 47-712 160.0 g Melamine resin L-117 33.3 g The resin solution having the above mixing ratio was added, and the mixture was further stirred and mixed for 10 minutes.

Compounded aluminum flake paint Aluminum flake paste 7130N 39.0 g (NV65%, manufactured by Toyo Aluminum Co., Ltd.) Mixed solvent (same as above) 135.0 g The above compounded substance is weighed in a 400 cc mayonnaise bottle and placed in a disper. After stirring for 10 minutes at a low rotation speed, acrylic resin 47-712 160.0 g Melamine resin L-117 33.3 g The resin solution having the above mixing ratio was added, and the mixture was further stirred and mixed for 10 minutes.

Blended clear paint Acrylic resin 44-179 100.0 g (NV50%, Dainippon Ink and Chemicals, Incorporated) Melamine resin L-117 35.0 g Solvesso # 150 67.2 g The above blend was mixed with 400 cc mayonnaise. After weighing in a bottle and mixing with a disper at a low rotation speed for 3 minutes, the viscosity was adjusted to 18 seconds with a Ford cup # 4 by adding Solvesso # 150.

Next, coating compositions were prepared with the coating composition ratios shown in Table 1.

[Table 1]

Comparative Examples 1 and 2 In Comparative Example 2, MT-500H used in Examples is used.
Paint composition of Comparative Examples 1 and 2 as shown in Table 1 under the same conditions as in Examples 1 to 3 except that MT-500B (trade name, manufactured by TAYCA CORPORATION, brand without surface treatment) was used in place of D. The composition was made. The difference in the composition between the case of using the titanium flakes and the case of using the aluminum flakes is that the volume ratio of the metal flakes in the coating film was the same. The above formulation was weighed in a 400 cc mayonnaise bottle, mixed with a disper at a low rotation speed for 5 minutes, and then the viscosity was adjusted to 13 seconds with a Ford cup # 4 by adding a mixed solution.

Example 4 and Comparative Example 3 The coating compositions of Examples 1 to 3 and Comparative Examples 1 and 2 were spray-coated on an electrodeposited and intermediately coated coated plate to a film thickness of about 15 μm for 10 minutes. After drying, spray-coat the compounded clear coating composition to a film thickness of 40 μm.
It was baked at 40 ° C. for 30 minutes. Colorimetric measurement of the paint film created by the gonio colorimeter GCMS-3 (Murakami Color Research Laboratory Co., Ltd.)
70 degrees incident angle, -50 degrees acceptance angle (diffusion side) to +
The "a" value at 60 degrees (reflection side) was measured and is shown in FIG.
The weather resistance of the coating film created next is sunshine super long life weather o-meter WEL-SUN-H
CH type (manufactured by Suga Test Instruments Co., Ltd.), the following operating conditions Test tank temperature 40 ℃ Black panel temperature 63 ± 3 ℃ Rainfall time 18 minutes Cycle 120 minutes 1 cycle 60 hours Shower water Ion-exchanged water to promote coating film Exposed, gloss meter UGV-4D
60 degree -6 of the coating film before and after exposure by (Suga Test Instruments Co., Ltd.)
Measure the 0 degree specular gloss value and use the following formula

[Equation 1] The gloss retention rate was obtained by the above to determine the weather resistance, and the results are shown in Table 2.

[0022]

[Table 2]

[0023]

Since the metallic coating composition of the present invention is rich in aesthetics and excellent in weather resistance, it can be used especially for automobile top coats, and its effect is extremely large.

[0024]

[Brief description of drawings]

FIG. 1 is a diagram showing a coating film formed by using Examples 1 to 3 and Comparative Examples 1 and 2 with an incident angle of 70 degrees using a goniocolorimeter.
It is a result of measuring the “a” value at the angle by changing the light receiving angle from −50 degrees (diffusion side) to +60 degrees (reflection side).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Kaoru Saito, 410, Oji, Osho, Nara Prefecture Showa Aluminum Powder Co., Ltd.

Claims (2)

[Claims] 1. A metallic coating composition comprising titanium flakes, a particulate metal oxide coated with an oxide or hydroxide of one or more elements of zirconium, aluminum and silicon, and a resin. object. 2. The metallic coating composition according to claim 1, wherein the particulate metal oxide is rutile type particulate titanium dioxide.