JPS5975961A - Electrically conductive electrodepositing paint - Google Patents

Abstract

PURPOSE:To provide the titled electrodepositing paint suitable for use in coating steel sheet, etc. and having excellent corrosion resistance, electrically conduttive performance, etc., by mixing a resin, carbon, a pigment, a solvent and water in a specified weight ratio. CONSTITUTION:14-18% resin, 1-3% carbon, 1-4% pigment such as titanium oxide or phthalocyanine blue, 4-8% solvent and the balance of water are mixed together to obtain the desired electrically conductive electrodepositing paint. The paint can be applied to steel sheet by electrodeposition, since the paint contains 1-3% carbon, the coated steel sheet after coating and drying has sufficiently electrically conductive performance so that the steel sheet coated with the paint can be further subjected to an electrodeposition coating. Further, the film of the paint of this invention has sufficient electrically conductive performance so that the steel sheet coated with the paint can be press-molded and spot-welded to form a automobile body.

Description

[Detailed Description of the Invention] Conventionally, automobile bodies, metal building materials, etc. have been constructed by welding thin steel plates, and then painted to improve the aesthetic appearance and prevent rust. Since it does not penetrate into the minute gaps formed between thin steel plates, there is a problem in that when car bodies and building materials are placed in a corrosive atmosphere for a long time, the steel plates in the minute gaps corrode.

As a result of various studies to solve the above problems, the present inventor found that by forming a conductive electrodeposited coating on thin steel plates, the above corrosion can be prevented, and since the coating is conductive, thin steel plates can be spot welded together. It turns out it can be done.

That is, 1. The present invention is applied to the above thin steel plate by electrodeposition, and is characterized by comprising wood n'814 to 18, carbon 1 to 3, pigment 1 to 4, solvent 4 to 8%, and residual water. The gist of this paper is a conductive electrodeposition coating that has the following characteristics.

Hereinafter, the present invention will be explained in detail using examples.

14 epoxy resin, 2 carbon, 25% pigment.

A conductive electrodeposition paint consisting of 5 g of solvent and residual water is poured into the electrodeposition bath. At this time, the properties of the electrodeposition paint are shown in Table 1.

Table 1 Table 2 shows the results of cationic electrodeposition at two different voltages by immersing a cold-rolled steel plate of 150 m x 150 m x 0.8 t in the above electrodeposition bath.

Table 2 Table 3 also shows the results of testing and evaluation of steel plates with a coating thickness of 5 μm in accordance with JIS K5400.

Table 3 Now, an insulating electrodeposition paint was cationically electrodeposited on a steel plate coated with the above-mentioned conductive electrodeposition paint at the 5 μm and a steel plate without any paint applied, and the coating film performance is shown in Table 4. show.

From Table 4 and above, the coating film formed by the conductive electrodeposition paint of the present invention has sufficient corrosion resistance.

In addition, since the paint of the present invention contains 1 to 3% carbon, it has sufficient electrical conductivity even in a dry state after application, and for this reason, it is possible to apply electrodeposition coating to a steel plate coated with the paint of the present invention. As shown in Table 4, two types of electrodeposition coating were applied: one was simply electrocoated on a steel plate, and the other was electrocoated on a steel plate coated with the paint of the present invention.

It has the same coating performance.

Furthermore, since the coating film of the two inventive paints has sufficient electrical conductivity, it is possible to press-form thin steel plates coated with the two inventive paints and spot weld them to form automobile bodies, building materials, etc. You can use these car bodies.

Micro gaps in building materials 2 For example, when spot welding is performed at multiple locations, the contact area between the thin steel plates between the nuggets is not coated because the paint does not penetrate even in dip coating such as electrodeposition. It is coated with paint so it will not corrode.

In the paint of the present invention, the carbon content is 1 to 3%, but if it is less than 1%, the electrical conductivity of the coating film will be low, and if it exceeds 3%, the dispersibility of pigments, resins, etc. in the bath will be poor.

Further, the pigments of the paint of the present invention include titanium oxide as a white pigment, red iron oxide, yellow iron oxide, phthalcyanine blue, Futashi 7 Nino Green as a colored pigment, and talc and baryta as an extender pigment.

Aspestin, china clay, stopp as an anti-rust pigment
chromate, lead silichromate, etc.

Claims (1)

[Claims] Resin 14-18, carphone 1-3%, pigment 1-4%,
A conductive electrodeposition paint characterized by consisting of 4 to 8% solvent and residual water.