JPH03146573A - Formation of colored coating film of new design - Google Patents

Abstract

PURPOSE:To obtain a colored coating film of new design, forming a clear layer of different two layers, changing transparency and developing rainbow color by angle of observation by applying a clear coating compound containing a combination of specific resins as main components to a material to be coated and curing the resins. CONSTITUTION:A clear coating compound comprising a resin composition, as a main component, which contains (A) a resin having 22-40 acid value, 100-150 hydroxyl number, SP1 solubility parameter of coating film and n1 refractive index, (B) a resin having 2-10 acid value, 30-80 hydroxyl number, SP2 solubility parameter of coating film, n2 refractive index and SP1-SP2:1.0-2.0 and ¦n1n2¦>=0.05 and further (C) a crosslinkable resin of aminoplast resin having compatibility with the components A and B or (block) polyisocyanate in the ratio of the component A/B of (20/80)-(70/30) and the components (A+B)/C of (80/20)-(40/60) is applied to a material to be coated and cured to give the objective varied coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical field The present invention relates to a method for forming a new design color coating film, and more specifically, by simply applying and curing a clear paint containing a combination of specific resins as a main component, an upper layer of submicron order can be formed. and form two resin layers with different refractive indexes as the lower layer,
This article relates to a method for forming a newly designed coating film that uses light interference to obtain a coating color that cannot be obtained with conventional coatings, and whose transparency changes depending on the viewing angle (and rainbow colors appear).

BACKGROUND OF THE INVENTION In fields where cosmetic properties are required, such as automobiles and home appliances, new facets such as mica, interference mica, graphite, and ultrafine titanium are being actively developed.

Problems to be Solved by the Invention The present invention is different from the prior art in that it aims to obtain a new design color based on the refraction and reflection of light in the resin layer and the interference phenomenon of light. In other words, when a transparent resin layer with a submicron order close to the wavelength of light is provided on top of a clear resin layer, the α phases of the reflected light at the internal boundary line and the reflected light at the surface are reversed and cancel each other out. It can be easily inferred from the principle of interference color development that a chromaticity of 1 H occurs, and that the color changes depending on the viewing angle.

Although it is not necessarily difficult to separately provide such a submicron-order clear layer on top of the clear coating film with current coating technology, it has not been realized due to problems such as pinholes and workability issues. .

Problems to be Solved by the Invention Therefore, without changing the normal clear coating process, it is possible to apply coatings with different refractive indexes by means of coating and drying sand.
It is an object of the present invention to provide a method in which a clear layer of a layer is formed and a coating film with a new design color can be obtained by the interference effect of light.

Means for Solving the Problems According to the present invention, the above object has an acid value of 22 to 40. Hydroxyl group fil○0-150. Solubility parameter Sl) + coating film, resin (1) with refractive index n1, acid (Fn 2 to 10. hydroxyl group (11i30 to 80°)
), provided that Spl Sp2 is within the range of 1.0 to 2.0, and the difference in the coating film refractive index is rll nzl 0.0
5 or more, and resin (1), +1 fat (2
) is compatible with aminoblast resin, polyisocyanate 1-, and blocked polyisocyanate (3), and the distribution ratio of resin (1)/'resin (2) is 20y.
” 80 to 70/30, resin (1) 10 resin 2).

The blending ratio of resin (3) is 80, y'2 0 to 406
This is achieved by a new design color coating film formation method characterized by applying a clear coating 1 containing a certain type of resin composition as a main component to the object to be coated and hardening it.

When two different types of resins are mixed and painted, if the solubility parameter Sp values of these resins are different, the resin with lower Sp tends to separate on top of the resin with higher Sp.

However, if the sp difference is too large, the resins cannot be mixed and the two will separate from each other at the coating stage. The compatibility of resins differs depending on their molecular weight, but the present inventors found that resins with molecular weights of 2,000 to 10, 0, which are commonly used in paints,
For resins with layer 0 or so, the difference in Sp value between the resins is 1.0 to 2. O. It has been found that when the ratio is preferably within the range of 1.0 to 1.5, both are uniformly mixed in a solution state, but are separated into two layers when applied to an object.

However, even if the resins are separated, it is not possible to separate the base resin by, for example, 0.1 μm based on the Sp difference alone.
It is difficult to float with a film thickness of this order. The present inventors have conducted intensive research to form a resin layer with a thickness of about 0.4 to 1 μm on a certain resin layer, which can be expected to have an optical interference effect. By making a difference in the reactivity with the resin, we were able to achieve our goal. That is, the present inventors set the amount of functional groups for reacting with crosslinkable resins such as aminoblast resin polyisocyanate and blocked polyisocyanate so that resin (1)>resin<2). Resin (2)
is formed by separating layers with a film thickness on the order of submicrons, and furthermore, the present inventors have found that by creating a refractive index difference between the resin layer (1) and the resin layer (2), both resin layers Light is reflected at the interface, and a new design coating film is obtained by the reflected light. It was discovered that a particularly useful new design coating film can be obtained when the reflected light is large and the refractive index difference lnl-n21 is 0.05 or more, preferably 0.1 or more, and these findings formed the basis of the present invention. It is.

The resin rods of resin (1) and resin (2) may be any resin rods that can be used as the clear coating 1, but transparency. Resin (1) is an acrylic resin from the viewpoint of light refractive index, coating performance, etc. Polyester resin, etc., and resin (2
) is particularly preferably a fluororesin or the like.

Of course, these resins must be compatible with the above-mentioned crosslinkable resin.

From the viewpoint of reactivity with the crosslinkable resin, the resin (1) used in the present invention has an acid value of 22 to 40. Hydroxyl value 100-150
The resin <2> has an acid value of 2 to 10. Hydroxyl value 30
~ SO, 5 pl LF is larger for resin (1), and the difference in SP value is l, assuming that the molecular weight of the resin used is about 2000 to 10000.
It should be in the range 0 to 2.0, preferably in the range 1.0 to 1.5. Furthermore, as mentioned above, the coating film refraction $n+, n2 of both resins is the difference 1n+
There is a need for n2l to be set to 0.05 or more, preferably 0.1 or more.

The higher the acid value and hydroxyl value of the resin, the more hydrophilic the entire system becomes, which is undesirable because the water resistance and weather resistance of the coating film deteriorates, and if it is too low, the hardening reaction with the crosslinkable resin is insufficient. Therefore, the physical and mechanical properties and mechanical durability of the coating film are deteriorated, which is not preferable.

As mentioned above, fluororesin is preferably used as the resin (2), but this has a Spa of 1
．． This is because SP value and refractive index difference can be easily controlled because the refractive index is about 0.1 lower than that of ordinary acrylic. However, when using acrylic resin such as 0% styrene-containing Lano 7
051;') may be used as resins (1) and <2>.

The clear paint of the present invention may optionally contain a surface conditioner (for example, Shin-Etsu Silicone KF-69. bayer silicon OL
, silicone-based products such as BYK-VP-300 [acrylic-based products such as Hypolyte, Modaflow, Mikirebe M K2O], ultraviolet absorbers (e.g. Tinuvin '328, Tinuvin 900, etc.), Sanol LS-770. Sanol LS-1
44, Sanol LS-292. A reaction catalyst (for example, a sulfonic acid derivative, a tin-arsenic metal, etc.) can be added as appropriate.

In addition, in the resin composition of the present invention, resin (1) (2>
, the blending ratio of (3) is resin (1) /'resin (2) 2
0/'80 to 70/30, and resin (1)
+ for resin (2), - resin (3) for 807' 20~4
It has been confirmed that it is necessary to select a range of 0 y' 60. If the amount of resin (2) exceeds this range, the film thickness of resin (2) will not reach a predetermined film thickness that will cause optical interference. Moreover, if the amount of resin (3) is less than 20, curing will be insufficient,
(If it exceeds 50, it becomes excessively hard and the desizing property decreases, which is undesirable.) The clear paint containing the resin composition of the present invention as a main component can be applied on top of the top coat by a normal coating method, and has crosslinking properties (cold resistance). Depending on the type, it hardens at room temperature or 140'C~
A two-layer clear film can be formed by baking and curing for about 20 minutes at 160°C.

In the present invention, resin (2) has a lower Sp than resin (1), so it easily floats on the surface, and since the reaction rate is slow, it is easily pushed out to the surface in an unhardened state. In any case, according to the method of the present invention, the transparency changes depending on the viewing angle and interference color appears due to the -times of coating operation, which is different from the conventional coating film. You can obtain a coating film with a unique design that is rich in color.

The present invention will be explained below with reference to Examples.

Production period 1 to 3 Three types of acrylic resins were produced using the seven-mer compositions shown in Table 1 by a conventional solution polymerization method. Acid value (AV) of these resins,
The hydroxyl value (○HV) and SP value are shown in Table 1.

All of these resins had an average molecular weight of about 10,000.

Examples 1 to 4 For each resin (1) obtained in Production Examples 1 to 3, the acid value (AV), hydroxyl value (OHV), and SP value as resin (2) are shown in Table 2. Fluororesin (manufactured by Asahi Glass) and butyl-modified melamine resin (knee pan 1) as resin (3)
28. A clear paint was prepared by blending the amounts of acrylic (acrylic surface finish M) and Modaflow (acrylic surface finish M) as shown in Table 2.

0, 8 mm x 7 cm x 15 cm
The surface of the steel was pre-treated with Surfdyne 5D-5000 (zinc phosphate surface treatment agent 1 Nippon Paint (ceramic)),
Power Top U-30 (cationic electrodeposition paint 1 made by Nippon Paint ■) Apply an undercoat to a dry film thickness of 20 μm and apply 180
Bake at ℃ for 20 minutes, then apply Olga P-2 gray intermediate paint (oil-free melamine paint 1 manufactured by Nippon Paint).
A test plate was prepared by coating it with a dry film thickness of 35 μm and baking it at 140°C for 20 minutes. The above test board was coated with the metallic base paint Superlac M-90 Silver (Nippon Paint (ceramic)) to a film thickness of 15 μm, and the clear paint obtained in each example was applied with Web I On Wet to a film thickness of 40 μm.
After coating to give a thickness of μm and baking at 140° C. for 20 minutes, each board was evaluated for the presence or absence of interference color. The results are shown in Table 2.

(Hereafter, extra white)

Claims (2)

[Claims] (1) Resin with acid value 22-40, hydroxyl value 100-150, solubility parameter Sp_1 coating, refractive index n_1
) and a resin (2) with an acid value of 2 to 10, a hydroxyl value of 30 to 80, a solubility parameter Sp_2 coating film, and a refractive index n_1, provided that Sp_1-Sp_2 is within the range of 1.0 to 2.0, and The difference in the refractive index of the coating film |n_1-n_2| is 0.0
5 or more, and aminoplast resins, polyisocyanates, which are compatible with resin (1) and resin (2),
Consists of a crosslinkable resin (3) selected from blocked polyisocyanates, with a blending ratio of resin (1)/resin (2) of 20/80 to 70/
30 and the blending ratio of resin (1) + resin (2)/resin (3) is 80/20 to 40/60. A new method for forming a color coating film with a new design. (2) Claim 1, wherein the resin (1) is an acrylic resin or a polyester resin, and the resin (2) is a fluororesin.
The method described in section.