JPS6077993A - Formation of metallic paint film - Google Patents

Abstract

PURPOSE:To form a paint film having mild metallic luster on the surface of an article to be coated by carrying out coating with paint contg. fine powder of a metal or a mineral and a dispersant by electrodeposition under stirring. CONSTITUTION:Paint for electrodeposition is modified by adding fine powder of a metal such as Al or brass or a mineral such as mica or ceramics and a dispersant such as nonionic surfactant. A colorant may be added to the paint. The average particle size of the fine powder is regulated to about 0.1-2mum, and the powder is added by about 1-2% of the amount of the solid matter in the paint. Coating is carried out with the modified paint by electrodeposition under stirring, and the resulting paint film is baked to form a paint film having a mild metallic tone.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a gold-tone coating film on the surface of an object to be coated.

Items made of Gold 8 itself or made of plastic that has been given electrical conductivity and are coated with metal for anticorrosion or decorative purposes, for example, if they have a lustrous luster such as nickel plating. There are many cases where it is preferred in itself, but it is the item itself, office equipment, home audio equipment, kitchen, kitchen electrical equipment! When used for parts such as a, it is often desired to have a golden-like finish with less harshness.

The present invention was developed to meet such demands, and uses a modified electrodeposition paint to which fine metal or mineral powder is added together with a dispersant and, if necessary, a colorant. This is a method for forming a metallic coating film on a coated article.

The objects to be coated to which the present invention is applied (the various articles mentioned above,
In other words, it refers to articles whose base is metal, and various articles whose base is metal or plastic and whose surface is coated with metal or plated. Of course, since the coating is electric coating, it does not include items that do not have electrical conductivity on their surfaces.

The paint used in the method of the invention is a modified electrocoating paint. As is well known, electrodeposition paints are classified into two types: cationic and anionic; either of them can be applied to the present invention.

The modification is carried out by the addition of additives.

The first additive is a metal σ] powder containing an alloy, typical examples of which are aluminum and brass. Although not such metals, fine powders of minerals that have a bright luster like metals, such as mica and ceramics, can also be used in addition in the same way as the fully bendable fine powders. Here, the term "fine powder" means that the powder is so fine that it can be uniformly dispersed in the electrodeposition paint by the help of the dispersant described below, and that phase separation does not easily occur. , if you are forced to learn numerical values, the average particle size is 0.1
It refers to something with a diameter of ~2μ. In addition, one load of the additive is about 1 to 2% of the solid content of the paint to be added experimentally;
deemed appropriate.

The second additive is a dispersant, and by its addition, the metal fine powder is uniformly maintained in the paint bath for a long time even under energized conditions. The most suitable such dispersant is a surfactant, especially a nonionic surfactant.

This is because when an anionic surfactant is added to anionic electrodeposition coating, the surfactant is naturally negatively charged in the electrolytic process, and migrates with the vehicle to the anode to be coated when electricity is applied. As a result, the appearance of the product is significantly deteriorated, and when used in cationic electrodeposition coating, it immediately reacts with the cationic vehicle to form an insoluble gelled product, making the bath unusable. be. Cationic surfactants also cause exactly the same phenomenon as the anionic surfactants, although the target baths are different.

The amount of nonionic surfactant to be added is experimentally determined to be approximately 1 to 5% based on the solid content of the paint to be added.

The third additive is a coloring agent. Normal electrodeposition paint itself\f! ILL color has a transparent or light R transparent color, but it is added when coloring is required due to design preference, and if there is no such request, it may not be added. The most suitable colorants are organic pigments. This is because inorganic pigments have a kind of filler effect and tend to impair the metal-like effect provided by the finely added metal powder.

To produce the paint bath used in the method of the present invention, the various additives mentioned above are added to a given electrodeposition paint, and if necessary, water is added to bring the solids content to 6%, which is most suitable for the electrodeposition conditions. If stirring is applied at this time, a uniform and modified paint bath can be quickly obtained.

The solids content in the paint bath is usually on the order of 6-20%.

In order to perform electrodeposition using such a modified electrodeposition paint bath, a regular jig for attaching the object to be coated is used, the object to be coated is attached to this in the usual manner, and the object is placed in the R1 bath. It is suspended and subjected to the prescribed electrodeposition coating while stirring.

Stirring is required to further enhance the dispersion effect of solids in the electrolytic bath, and this purpose can be easily achieved, for example, by attaching a propeller-type porta-pull stirrer to the electrolytic bath. A similar stirring effect can also be obtained by circulating the electrolytic bath in the electrolytic cell 7 to 8 times per hour 1+ once per hour.

Electrolysis conditions are electrolysis voltage 10-200V, bath temperature 15-200V.
30°C, current density 0, 2 to 10 A/dm2, and energization time of about 30 seconds to 3 minutes, and these conditions are normal il! There is nothing particularly different from the solution conditions.

After the predetermined electrodeposition coating is performed in this way, the object to be coated with the # film electrodeposited is taken outside, washed with water and subjected to baking.The main body of the paint bath according to the present invention is Since it is a paint, it is natural that this baking is an indispensable operation.1.
C120 to about 30 minutes.

Examples are given below.

Example 1 10 vertical x 5 horizontal nickel plated with a thickness of 10 μ
× Atsuza 1 The paint that was commonly used for coating steel plates was a water-dispersible acrylic-melamine anionic electrodeposition paint with a molecular weight of 20,000 to 220 (lO), and an average particle size of 0.3゛. It was modified by adding 10 f/l of Al/μ paste and 4 g/l of dispersant at the same time.The dispersant used was a nonylphenol type nonionic surfactant (the number of moles of ethylene oxide added). , 25).

The object to be coated was suspended in the above modified paint which had been diluted with water and adjusted to a solid content of 10%, and was heated under mechanical agitation using a propeller-type agitation at an electric pressure of 10OV and a current density of 0.5A.
/mu2. Electrodeposition coating was performed with a current application time of 3 minutes. The object to be coated was then lifted out of the bath and then baked at 180'C for 20 minutes. The luster of the resulting coating film had a mild metallic luster, with the sharp luster of the nickel plating having been alleviated. Not only that, but the physical performance of the coating film showed no substantial difference from that of the unmodified coating material.

Example 2 An 18-8 stainless steel plate measuring 10 length x 5 width x 1 width was used as the object to be coated, was fixed to a fixing jig in the usual manner, and suspended in a bath of modified paint for electrodeposition. Painted.

The paint used was a water-based cationic acrylic electrodeposition paint, which was modified with the following three additives.

Brass fine powder: average particle size o, 5it...5
y/I1 dispersant: β-naphthol ethylene oxa 41
Nonionic surfactant which is a 20 molar adduct...31/1s Colorant: Phthalocyanine Green (C, 1,74260
)・・・・・・・・・0.89/1 After adding the above additives, water is added and mixed to adjust the solid content to 15%, which is used as an electrodeposition paint bath, and the above-mentioned coating is added to the bath. The material was suspended and stirred by closely circulating current at an electrolytic voltage of 100 V.

The object to be coated was then taken out of the bath and subjected to a baking treatment at 160° C. for 30 minutes.

The resulting coating film was a red coating film with a modern luster, and its physical properties were not significantly different from those obtained by electrodeposition using a paint without additives.

Applicant: Shimizu Shoji Co., Ltd.

Claims (1)

[Scope of Claims] 1) An article to be coated characterized in that it is electrodeposited with a modified electrodeposition paint in which a fine metal or mineral powder is added together with a dispersant and, if necessary, a colorant, while stirring. Method for forming a metallic coating film 2) The method for forming a metallic coating film according to claim 1) wherein the metal is aluminum or brass 3) The mineral is:
4) A method for forming a metal-like coating film according to claim 1) which is mica or ceramic; 4) A method for forming a metal W1 coating film according to claim 1) wherein the dispersant is a nonionic surfactant.