JPH0619080B2 - Metallic paint composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a metallic coating composition containing a specific silane coupling agent and excellent in water discoloration resistance.

2. Description of the Related Art In metallic paints containing metal powder such as aluminum, the coating film turns black due to the influence of water on the long-term performance, and such discoloration prevention function (water discoloration resistance) is always a problem. Especially in the automobile industry and the like, metallic coating tends to be applied to urethane bumpers recently, but the amine catalyst contained at the time of formation creates a basic atmosphere, in which case the metallic coating is resistant to water discoloration. Is a particularly serious problem.

As a solution to this problem, a polymer protective layer was conventionally formed around a metal piece such as aluminum, and a study was conducted for the purpose of improving the hydrophobicity of the polymer itself, but it is not very effective in improving the resistance to water discoloration. However, it has been proposed to use high-purity aluminum or to coat aluminum, but there is a problem in terms of economic efficiency, and there is a problem in terms of difficulty in obtaining each grade or metallic feeling. There was a strong demand for improvement.

Problems to be Solved by the Invention An object of the present application is to obtain an effective and easy metallic discoloration resistance and a metallic coating composition having improved metallic feeling.

Means for Solving the Problems The above object is to provide a metallic coating composition comprising 0.1 to 20% by weight of metal powder, based on the total solid content, and comprising a resin, a solvent and a coating additive. (In the formula, X is a group reactive or compatible with an organic material,
Y ₁ , Y ₂ and Y ₃ are each an OH group or a group which hydrolyzes to form silanol, which may be the same or different) and a silane coupling agent represented by
This can be achieved by a water-resistant discoloration-resistant metallic coating composition characterized by containing 0.1 to 5% by weight.

The term "organic material" used in the specification of the present application means
The term "inorganic material" means an organic component contained in the coating material such as a resin and an additive, and the term "inorganic material" means an inorganic component contained in the coating material such as metal powder.

Among the compounds represented by the above formula, some are used for the purpose of improving the adhesiveness of concrete and the like, but there is no case where such a compound was compounded in a metallic paint, and this time, the present inventors have made the metallic paint water resistant. It has been found that it is useful not only for discoloration but also for significantly improving metallic feeling.

In the silane coupling agent represented by the above general formula, Y ₁ , Y ₂ and Y ₃ are each an OH group or a group which is hydrolyzed to silanol, such as silanol, and alkoxy or chlorine such as methoxy and ethoxy. Is. Regarding the reaction mechanism of these groups, there are still many unclear parts, but it is presumed that they are hydrolyzed and immediately bond with the metal powder of the inorganic material, for example, aluminum. On the other hand, X
Is a prepolymer (number average molecular weight) of a group that is reactive or compatible with organic materials, such as vinyl group, epoxy group, amino group, alkyl group, coating resin (eg polyester, polyether, poly (meth) acryl, etc.) About 4000 or less) and the like.

Of these groups, for example, epoxy, amino, etc. react with the carboxyl group of the paint base resin of organic material, and vinyl group, alkyl group, prepolymer of paint resin, etc. show compatibility with the paint base resin. .

Such a silane coupling agent can be easily synthesized by those skilled in the art if desired, and various commercially available products such as KBM5
03 (manufactured by Shin-Etsu Silicone) KBM403 (Shin-Etsu Silicone Co., Ltd.) Etc. are available.

The above silane coupling agent was added to the total solid content of 0.1.
When added to a usual metallic paint comprising resin, solvent, and other paint additives, containing ~ 20% by weight of metal powder,
The Y portion or silanol produced by the hydrolysis of the Y portion is bonded to a metal piece such as aluminum to protect the metal piece with a silicon coupling agent.
Through the part, it is anchored by reaction or compatibility with the film-forming base resin, and as a result, a much stronger protective layer is formed around the metal piece than when the metal piece is simply protected by the polymer. . The degree of resistance to discoloration when the coating film of the metallic paint is immersed in warm water, that is, the degree of water discoloration resistance, is whether or not this metal protective layer is formed, and how strongly the protective layer is formed. In fact, the metallic paint containing the silane coupling agent of the present invention has extremely excellent resistance to water discoloration and is immersed in warm water (40 ° C. for 3 days) even in a basic atmosphere. ), It is recognized that there is almost no discoloration.

Furthermore, when a silane coupling agent is blended, the solvent of the paint does not necessarily have to be organic, and even in water-based paints, there is no discoloration, and therefore the door is open to water-based metallic paints.

In the metallic coating composition of the present invention, the effect that the hydrophobicity of Si improves the water resistance of the coating film, and the appearance of the coating film (glare, gloss) is extremely excellent.

In the present invention, the silane coupling agent represented by the above formula is added in an amount of 0.1 to 5% by weight, preferably 0.3 to 3.0% by weight, based on the total solid content of the coating material. If less than 0.1%, the effect is insufficient, and 5
It is because it is recognized that the workability of the metallic paint deteriorates and the tendency to cause cissing is exceeded when the ratio exceeds%.

The metallic paint of the present invention thus has excellent resistance to water discoloration and is particularly useful for urethane bumper metallic paints, water-based metallic paints and the like.

The present invention will be described below with reference to examples. Unless stated otherwise, parts and percentages are by weight.

Example 1 A metallic paint for acrylic urethane paint having the following composition was prepared.

Silane coupling agent KBM503 and acrylic resin solution are added to aluminum paste 1100NA for 5-10 at room temperature.
After stirring for a minute, a predetermined amount of toluene and Disparlon 4200-10 was added, and stirring was continued for about 10 minutes to obtain a metallic paint.

Example 2 As the silane coupling agent in Example 1, KBM was used.
403 [Shin-Etsu Silicone Co., Ltd. silane coupling agent, The same production was performed using.

Example 3 KBM9 as the silane coupling agent in Example 1
03 [Shin-Etsu Silicone Co., Ltd. silane coupling agent, The same production was performed using.

Example 4 500 parts of toluene and 450 parts of butyl acetate were charged into a 4-neck Kolben equipped with a cooling pipe, a temperature controller, a dropping funnel, and a nitrogen introducing pipe, and the temperature was raised to 115 ° C. to obtain MMA600.
Part, nBA150 part, nBMA100 part, 2HEMA1
3 parts of a solution consisting of 43 parts, 7 parts of GMA and 15 parts of AIBN
The mixture was added dropwise over a period of time and then kept at 115 ° C. for 30 minutes. t-
A solution of 5 parts of butyl peroxy 2-ethylhexanoate and 50 parts of butyl acetate was added dropwise over 30 minutes, and then 90 minutes 11
The temperature was kept at 5 ° C. to obtain an acrylic resin solution having a nonvolatile content of 50% and a viscosity of X. KBM903 5 used in Example 3 was added to this.
KBM5 in Example 1 using a silane coupling agent-modified acrylic resin solution which was added at 30 ° C. for 30 minutes.
A metallic paint was prepared with a composition excluding 03.

Comparative Examples 1-2 A metallic base paint was prepared by the same production, and Comparative Example 1
Is a mixture of 10 parts of Coronate EH and stirred.

In Comparative Example 2, 16.5 parts of U-Van 20SE-60 was added, stirred and applied.

Clear paint A Clear paint A applied to the metallic paints of Application Examples 1 to 4 and Comparative Example 1 is Acrytec A-801 (manufactured by Dainippon Ink and Chemicals, Inc.) 100 parts Coronate EH (manufactured by Nippon Polyurethane Co., Ltd.) 18 parts Mixing and stirring Then, the viscosity was adjusted to 16 seconds (# 4 Ford cup 20 ° C.) with a mixed solvent of xylene 80 and Solvesso # 10020.

Clear Paint B The clear paint B applied to the metallic paints of Application Examples 5 to 8 and Comparative Example 2 was Acridic A-801 100 parts U-Van 20SE-60 35.7 parts. Mix and stir, and Solvesso # 100 gives a viscosity of 25 seconds. (# 4 Ford cup 20 ° C.).

Application Examples 1 to 4 Application Examples 1 to 4 correspond to Examples 1 to 4 respectively.
110 parts of H (manufactured by Nippon Polyurethane Co., isocyanurate modified product of hexamethylene diisocyanate) was added, and a mixed solvent of toluene 10, butyl acetate 20, xylene 50, Solvesso # 100 (Aromatic hydrocarbon solvent manufactured by Esso Co.) 20 was added. The viscosity was adjusted to 13 seconds (# 4 Ford cup 20 ° C.) and applied by air spray. About 3 minutes after that, clear paint A was applied by air spray and baked at 60 ° C. for 30 minutes.

Application Examples 5 to 8 In Application Examples 5 to 8, 16.5 parts of U-Van 20SE-60 (a butylated melamine resin solution manufactured by Mitsui Toatsu Chemicals, Inc.) was added to each of the metallic paints of Examples 1 to 4, and toluene 3 was added after stirring.
0 parts, Solvesso # 10040 parts, butyl acetate 20 parts,
The viscosity was adjusted to 14 seconds (# 4 Ford cup 20 ° C.) with a mixed solvent consisting of 10 parts of n-butanol. This coating liquid was applied by air spray, and after about 3 minutes, clear coating B was applied by air spray and baked at 120 ° C. for 30 minutes.

All base materials used were Bayflex 100 manufactured by Sumitomo Bayer Urethane Co., Ltd. The results are shown in the table below.

Claims (2)

[Claims] 1. A metallic coating composition comprising 0.1 to 20% by weight of metal powder based on the total solid content and comprising a resin, a solvent and a coating additive. (In the formula, X is a group reactive or compatible with an organic material,
Y ₁ , Y ₂ and Y ₃ are each an OH group or a group which hydrolyzes to form silanol and may be the same or different.) A silane coupling agent represented by 0.1 to 5 relative to the total solid content. A water-resistant discoloration-resistant metallic coating composition characterized by being blended in a weight percentage. 2. A prepolymer of a coating resin such as a vinyl group, an epoxy group, an amino group, an alkyl group, or a polyester, polyether, poly (meth) acryl, etc., when the group (X) which is reactive or compatible with an organic material. The composition according to claim 1, which has a number average molecular weight of 4000 or less.