JPH01153761A - Pigment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel pigment, and more particularly to a pigment useful for forming a clear coat layer when painting the body of a passenger car.

(Prior Art) Body painting of passenger cars is carried out for the purpose of protecting the car body from corrosion, etc., and giving it an aesthetic appearance such as color and gloss. The process generally proceeds in the order of surface treatment of the vehicle body material, undercoating, intermediate coating, and topcoating. A clear coat layer made of a transparent resin is formed on the top coat layer to protect the top coat layer.

Recently, in order to improve the fashionability of passenger cars, aluminum powder has been mixed in with the above-mentioned top coat layer in addition to color pigments to give the overall metallic color tone. The aluminum powder to be mixed has a particle size usually on the order of several tens of micrometers.

Therefore, the color tone received from the top coat layer is a combination of metallic luster based on the reflected light from the aluminum powder and color based on the reflected light from the colored pigments blended together. In this case, the colored pigment is opaque;
Moreover, it does not itself have glittering properties.

(Problems to be Solved by the Invention) The present invention is a completely new pigment, which itself has glitter, transparency, and is colored. The present invention aims to provide such pigments.

(Means for Solving the Problems) In order to achieve the above object, the pigment of the present invention has a structure including a porous layer formed on the surface and a dye adsorbed on the porous layer, It is characterized by being aluminum particles having an average particle size of 0.2 μm or less.

The pigment of the present invention is composed of aluminum particles having an average particle size of 0.2 μm or less as a hese.

The reason why the average particle size is limited to 0.2 μm or less is to impart transparency to the aluminum particles. That is, the wavelength of visible light is 3,800 to 7,800 people (0.38 to 0.000).
78 μm), therefore, theoretically, if the particle size of the aluminum particles is made smaller than 0.38 μm, the aluminum particles will not be visually recognized and will actually function as a transparent body.

Such aluminum particles can be easily prepared by pulverizing aluminum foil with a pulverizer such as a ball mill. For example, when grinding aluminum foil with a thickness of 1 to 2 μm using a ball mill,
0mm steel ball as media, rotation speed 50-60rpm
The ball mill may be operated for 48 to 72 hours.

A porous layer is formed on the surface of the aluminum particles of the present invention. This porous layer can be formed as an oxide film on the surface by subjecting the above-mentioned pulverized aluminum particles to an alumite treatment such as the usual sulfuric acid method. Alternatively, the aluminum foil described above may be subjected to an alumite treatment in advance to form an oxide film on its surface, and then this foil may be crushed. If the thickness of this porous layer is too thin, as will be described later, the adsorption amount of the dye that adsorbs to this porous layer and imparts coloring properties to the particles will decrease, resulting in insufficient coloring properties of the particles, and conversely, this This is because if the thickness is too thick, the amount of dye adsorption increases, which in turn reduces the transparency of the entire particle.

The dye to be adsorbed to this porous layer is not particularly limited and may be selected appropriately depending on the desired color.For example, a disazo dye may be used as a red dye, and a phthalocyanine dye may be used as a blue dye. I can give it to you.

The dye can be adsorbed onto the porous layer by immersing the aluminum particles described above in an aqueous dye solution of a predetermined concentration. At this time, since the adsorption amount changes depending on the concentration of the dye aqueous solution, the immersion treatment time, and the temperature during the immersion treatment, the above factors may be appropriately selected in relation to the desired adsorption amount. Usually dye concentration 1-2%, processing time 4-5 minutes, processing temperature 70-90°
C is preferred.

In this way, the pigment of the present invention having a particle size of 0.2 μm or less and having a dye of a predetermined color adsorbed in the porous layer on the surface is obtained.

Next, when forming a clear coat layer using this pigment, this pigment can be blended with a varnish made by diluting acrylic melamine resin with a solvent such as toluene, and used to obtain an appropriate viscosity. For example, titanium oxide (white)
It should be avoided to use it in combination with other colored pigments such as. The reason for this is that the unique color tone of the pigment of the present invention is inhibited by other colored pigments used in combination.

For example, the above-mentioned varnish preferably has a composition of 20 to 23% by weight of acrylic melamine resin and 75 to 80% by weight of pigment 1 to 2 of the present invention and 75 to 80% by weight of solvent. This is because if the amount of the pigment blended is less than 1% by weight, the unique color tone of this pigment will not be exhibited, and if it is more than 2% by weight, uniform blending becomes difficult.

(Function) Since the pigment of the present invention has a particle size smaller than the wavelength of visible light, it is transparent itself, and the color of the dye it has adsorbed has a bright color tone that stands out. The clear coat layer coated with this material shines in a dreamlike color that has never been seen before, making it possible to significantly improve the appearance of a passenger car.

(Example of the Invention) After pulverizing aluminum foil with a thickness of 1.5 μm, the resulting fine powder is subjected to an alumite treatment using a normal sulfuric acid method to form a porous layer with a thickness of 0.05 to 0.1 μm on the surface of each particle. A thick oxide film was formed.

This powder was mixed with a 1.5% aqueous solution of disazo dye (liquid temperature: 8
0°C) for 4.5 minutes, it was filtered, thoroughly washed with water, and dried. Then, use a filter to set the value to 0.2.
A fine powder of µm or less was collected. The obtained fine powder was transparent and sparkling red.

1.5% by weight of this pigment, 21% of acrylic melamine resin
．． A paint was prepared by blending 5% by weight and 77% by weight of toluene, and applied on top of the white topcoat layer containing titanium oxide.

The overall color tone was a mixture of glossy red and white, giving a fantastic impression.

(Effects of the Invention) As is clear from the above description, the pigment of the present invention consists of a porous layer formed on the surface and a dye adsorbed on the porous layer, and has an average particle size of 0. .Since the aluminum particles are less than 2 μm in size, the color tone it gives is a transparent and shining color tone of the dye, and when applied to the clear coat of a passenger car, it is more brilliant than ever before, making it an excellent product for passenger cars. It can impart fashionability and has great industrial value.

Applicant: Mitsubishi Motors Corporation Agent Patent Attorney Kanji Nagamon

Claims (1)

[Claims] A pigment characterized in that it has a porous layer formed on its surface and a dye adsorbed on the porous layer, and is aluminum particles having an average particle size of 0.2 μm or less.