JPH06182294A - Pearl-like coating film structure - Google Patents

Abstract

PURPOSE:To enable a pearl-like finishing similar to the finishing obtained by such a method without using a pearlescent pigment, that the pigment component mixing an aluminum powder pigment and a titanium oxide pigment in a specified ratio is incorporated in a color base-coating. CONSTITUTION:The color base-coating layer containing the pigment component mixing in the ratio 10-600 pts.wt. titanium oxide pigment, 20-350 pts.wt. preferably, per 100 pts.wt. aluminum powder pigment having 10-25mum average grain diameter and a clearcoat layer is laminated on the surface of a body to be coated. And, the compounding of the aluminum powder pigment in the mixed pigment to the color base-coating layer is 1-20 PHR, 2-15 PHR preferably. And, the L value of the coating film is 25-65. In this way, the similar pearl-like finishing is attained without using the pearlescent pigment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pearl-like coating structure, and more specifically, a novel pearl-like coating structure capable of imparting a pearl-like effect by using a color base coat containing no pearl pigment. It is about.

[0002]

2. Description of the Related Art The conventional pearl-like paint finish involves applying an undercoat coating to the object to be coated, applying a color base coat on it, and then heat-curing it. A base coat containing a pearl pigment is applied to the above, a clear coat is further applied in an uncured state, and both coating films are heated and cured at the same time, which is a so-called 3 coat 2 bake system.

Of course, passenger cars, motorcycles and the like finished in a pearly tone by using this coating method have no particular problem in the finish itself and are well received in the market.

[0004]

However, the conventional coating method is 3 coat 2 in the coating process excluding the undercoat.
Since the bake method is used, we want to simplify the coating process from the viewpoint of productivity, and since the pearl pigment is expensive and the coating cost is higher accordingly, the same pearl finish can be achieved without using the pearl pigment. There is a strong need in the art for the development of coating structures that enable it.

[0005]

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention oxidize an aluminum powder pigment into a color base coat used in a conventional pearl finish finishing process. By containing a pigment component in which a titanium pigment is mixed in a specific ratio,
The present invention has been completed by finding that one of the three coating processes can be omitted, and a coating film structure with a pearl finish similar to the conventional finish can be obtained.

Thus, according to the present invention, the aluminum powder pigment (a) and the titanium oxide pigment (b) having an average particle size of 10 to 25 μm and the titanium oxide pigment (b) are (b) based on 100 parts by weight of (a) on the surface of the object to be coated. The present invention provides a pearl-like coating structure comprising a color base coat layer containing a pigment component mixed in a proportion of 10 to 600 parts by weight, and a clear coat layer laminated on the color base coat layer.

The material to be coated used for forming the pearl-like paint film structure of the present invention is not limited as long as it can be coated, and specifically, automobiles, motorcycles, scooters, appliances for household appliances, etc. The metal or plastic skin used in the above can be mentioned. These materials to be coated have a surface, if necessary, a conventionally known chemical conversion treatment,
A base coat may be applied.

The color base coat layer in the present invention is
As a pigment that imparts a pearl effect, a specific mixture of an aluminum powder pigment and a titanium oxide pigment as an essential pigment component,
In addition to this pigment, an achromatic color pigment and / or a chromatic color pigment usually used for coloring are included. As the binder resin other than the pigment component, thermosetting resins such as alkyd resin, oil-free alkyd resin, and acrylic resin are used, and as the curing agent component of these resins, amino resin, polyisocyanate, etc. are used. Further, as the solvent, aliphatic hydrocarbon, aromatic hydrocarbon, ketone, ester and the like can be used.

In the mixed pigment of the aluminum powder pigment and the titanium oxide pigment, which are used for the color base coat layer and impart the pearl effect, the ratio of both is 10 to 600 parts by weight, preferably 20 to 3 parts by weight with respect to 100 parts by weight of the former.
It is in the range of 50 parts by weight. The latter titanium oxide pigment is 10
Even if the amount is less than 600 parts by weight or more than 600 parts by weight, it is impossible to obtain the pearl effect.

The content of the aluminum powder pigment in the above-mentioned mixed pigment in the color base coat layer is 1 to 20 PH.
R, preferably 2 to 15 PHR. Outside of this range, a suitable pearl effect cannot be obtained.

The color base coat layer in the present invention can be colored in a desired hue by using a coloring pigment in addition to the above-mentioned aluminum powder pigment and titanium oxide pigment.

In the present invention, the L value of the coating film structure imparting the pearl effect and the average particle diameter of the aluminum powder pigment used in the color base coat layer have a considerable influence on the imparting of the pearl effect. For example, in the case of a coating film having an L value of 25 to 65, the average particle diameter of the aluminum powder pigment is 10 to 15 μm.
It is preferable to use a material having a relatively small particle diameter, and a material having a relatively large particle diameter of 15 to 20 μm when the L value is 45 to 85. Further, when the L value is in the range of 55 to 95, the average particle diameter of the aluminum powder pigment is 20 to 25.
It is preferable to use one having a large value of μm.

Here, the L value means the lightness index in the Hunter color difference formula obtained from the tristimulus values X, Y, and Z defined in JIS 28722.

The hue of the color base coat layer is not particularly limited, but it is generally difficult to obtain a pearl effect when the hue is red or yellow. However, even with these hues, the effect of the present invention can be expected when the Munsell chroma is 14 or less.

Next, as the clear coat layer, a transparent clear paint comprising a vehicle component excluding the pigment component of the above-mentioned color base coat layer or a transparent coloring pigment is added to the transparent clear paint.
A color clear coating compound containing PHR or less is used.
Further, a pearl pigment may be added to the transparent clear coating material within a range that does not impair the transparency.

In the formation of the color base coat layer and the clear coat layer described above, first, the color base coat is applied so as to have a dry film thickness of 20 to 40 .mu.m, and then in the uncured state, a clear coat having a dry film thickness of 20 to 40 is applied. 40μ
It can be carried out by a two-coat one-bake method in which coating is performed so that the coating film has a thickness of m, and both coating films are simultaneously heated and cured. Of course, it does not matter if it is formed by a two-coat, two-bake method. As a coating method, ordinary coating means such as air spray coating and electrostatic coating are used. The heat curing of the coating film is 7
The heating is performed at 0 to 140 ° C. for 20 to 30 minutes.

[0017]

The pearl-like coating film structure obtained according to the present invention is obtained by using a specific combination of an aluminum powder pigment and a titanium oxide pigment, without using a pearl pigment.
Further, by defining the L value of the coating film and the average particle size of the aluminum pigment, it is possible to more suitably give a finish similar to the conventional pearl finish to automobiles, motorcycles and the like. This can be understood from the reflection curve diagram of the conventional coating film having a pearl finish and the coating film structure obtained according to the present invention, which were measured using a goniospectrophotometer.

[0018]

EXAMPLES The present invention will be specifically described below with reference to examples. "Part" indicates "part by weight".

Example 1 The following color base coat is spray-coated on a surface-treated steel sheet to a film thickness (dry film thickness, the same applies hereinafter) of 30 μm. Then, the following clear coat is applied wet-on-wet to the thickness of 30 μm on this coating film, and the coating is heat-cured at 70 ° C. for 30 minutes. The coating film structure thus obtained has a pearl effect, and this film structure has a gonio-spectrophotometer (GONIO-Spectro manufactured by Murakami Color Co., Ltd.).
A reflection curve diagram obtained by using a photometer) is shown in FIG.

Color Base Coated Retan PG-60 No.519 Metallic Base ⁽¹⁾ 76.0 parts ("Retan PG" is an acrylic resin paint manufactured by Kansai Paint Co., Ltd.) Retan PG-60 No.618 Green 11.5 parts Retan PG-60 Blue PK -110 2.8 parts RETAN PG-60 No.400 black 5.7 parts RETAN PG-60 No.132 white ⁽²⁾ 4.0 parts ──────────────────────── ─────────── Total 100.0 parts ⁽¹⁾ Mixing ratio of main agent / hardening agent (weight): 100/10
(Similar to the following examples) Aluminum powder pigment (manufactured by Toyo Aluminum Co., Ltd.) Content: 9 PHR Aluminum powder pigment Average particle size: 10 to 15 μm ⁽²⁾ Using titanium oxide pigment manufactured by Teika (same as the following examples) Oxidation Titanium / aluminum pigment blending ratio (weight): 28 /
100 ⁽³⁾ L value of coating film: 53 clear coat compounded RETAN PG-60 top coat clear 100.0
Part Main agent / Curing agent: 100/10 FIG. 1 shows a pearl coating color using only a pearl pigment, a metallic pigment using only an aluminum pigment, and the coating film structure of the present invention, which are changed using a goniospectrophotometer. It is a plot of angle and hue. The pearlescent coating structure of Example 1 is close to the curve of the pearl coating color using only the pearl pigment, and it can be confirmed by visual evaluation that the pearl finish is obtained.

The pearl coating color was replaced by replacing the aluminum powder pigment in the metallic base of the color base coat with a pearl type pigment (Pearl mica "Iriodin 111 pearl" manufactured by Merck & Co., Inc.) and using Retan PG-60 N.
o.132 White is excluded. Similarly, the color of the metallic coating is from the color base coat formulation to the resin PG-
60 No. 132 White is excluded.

Example 2 A pearl-like coating film was obtained in the same manner as in Example 1 except that the following color base coat was used. The same effect as that of the first embodiment can be confirmed from FIG. The pearl coating color and the metallic coating color were prepared in the same manner as in Example 1.

Color Base Coated Retinal PG-60 No.519 Metallic Base 36.0 parts Retan PG-60 No.400 Black 54.1 parts Retan PG-60 No.132 White 9.9 parts ────────────── ───────────────────── Total 100.0 parts Aluminum pigment content: 2 PHR Aluminum pigment average particle size: 10-15 μm Titanium oxide / aluminum pigment: 300/100 Coating film L value of 35: Example 3 Example 1 except that the following color base coat is used.
A pearly paint film was obtained in the same manner as in. The same effect as that of the first embodiment can be confirmed from FIG. The pearl coating color and the metallic coating color were prepared in the same manner as in Example 1.

Color base coat formulation RETAN PG-60 No.762 base coat 72.5 parts RETAN PG-60 No.132 white 27.5 parts ──────────────────────── ────────── Total 100.0 parts Aluminum pigment content: 12 PHR Aluminum pigment average particle diameter: 15-20 μm Titanium oxide / aluminum pigment: 150/100 L value of coating film: 74 Example 4 Colors below Example 1 except using a base coat
A pearly paint film was obtained in the same manner as in. The same effect as that of the first embodiment can be confirmed from FIG. The pearl coating color and the metallic coating color were prepared in the same manner as in Example 1.

Color Base Coat Blend Retan PG-60 No.568 Base Coat 57.0 Parts Retan PG-60 No.132 White 43.0 Parts ──────────────────────── ────────── Total 100.0 parts Aluminum pigment content: 6 PHR Aluminum pigment average particle size: 20-25 μm Titanium oxide / aluminum pigment: 500/100 L value of coating film: 89

[Brief description of drawings]

FIG. 1 is a reflection curve diagram of a pearl finish coating, a conventional pearl finish coating, and a metallic coating formed according to Example 1, measured by a goniospectrophotometer.

FIG. 2 is a reflection curve diagram of a pearl finish coating, a conventional pearl finish coating, and a metallic coating formed according to Example 2, which are measured by a goniospectrophotometer.

FIG. 3 is a reflection curve diagram of a pearly finish coating film, a conventional pearly finish coating film, and a metallic coating film formed according to Example 3, which were measured by a goniospectrophotometer.

FIG. 4 is a reflection curve diagram of a pearly finish coating film, a conventional pearly finish coating film, and a metallic coating film formed according to Example 4 as measured by a goniospectrophotometer.

Claims (5)

[Claims] 1. An average particle size of 10 to 25 μm on the surface of the article to be coated.
m of the aluminum powder pigment (a) and the titanium oxide pigment (b) are (b) 10 to 60 with respect to 100 parts by weight of (a).
A pearl-like coating structure comprising a color base coat layer containing a pigment component mixed in an amount of 0 part by weight and a clear coat layer laminated on the color base coat layer. 2. The color base coat layer has an average particle size of 10
A pigment component which is obtained by mixing the titanium oxide pigment (b) in an amount of 10 to 600 parts by weight with respect to 100 parts by weight of the aluminum powder pigment (a) having a particle size of ˜15 μm, and having an L value of 25 to 65. The pearl-like coating film structure according to claim 1, which forms a coating film. 3. The color base coat layer has an average particle size of 15
A pigment component comprising a mixture of the titanium oxide pigment (b) and the titanium oxide pigment (b) in an amount of 10 to 600 parts by weight with respect to 100 parts by weight of the aluminum powder pigment (a) having a particle size of 20 μm and an L value of 45 to 85. The pearl-like coating film structure according to claim 1, which forms a coating film. 4. The average particle size of the color base coat layer is 20.
The pigment component is obtained by mixing the titanium oxide pigment (b) in an amount of 10 to 600 parts by weight with respect to 100 parts by weight of the aluminum powder pigment (a) having a particle size of 25 μm, and having an L value of 55 to 95. The pearl-like coating film structure according to claim 1, which forms a coating film. 5. The pearly paint film structure according to claim 1, wherein both the paint film layers of the color base coat layer and the clear coat layer are formed by two-coat one-bake coating.