JPS61235598A - Rust preventing treatment of article having bag structure - Google Patents

Abstract

PURPOSE:To remarkably enhance the rust preventing effect by forming electrodeposited electrically conductive paint films on the surface and inside of an article having a bag structure and by forming plated layers on the paint films. CONSTITUTION:An article having a bag structure is immersed in paint for electrodeposition contg. an electrically conductive material such as paint for electrodeposition contg. 5-10% carbon to form electrodeposited electrically conductive paint films on the surface and inside of the article. After the paint films are cured by baking, the article is immersed in a plating soln. to form plated layers on the electrically conductive films.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for rust-preventing an article having a bag structure, and more particularly, to a rust-preventing treatment method for an article having a bag structure, and more specifically, for treating rust-prone areas on the surface and inner surface of an article having a bag structure. The present invention relates to a rust-preventing treatment method for forming a conductive electrodeposition coating film and a plating layer on a metal.

[Conventional technology]

Conventionally, when painting objects such as automobile bodies, which are made up of overlapping steel plates, pre-treatments such as degreasing and chemical conversion treatment necessary for painting are performed, and then the undercoat, intermediate coat, and topcoat are applied. Either sequentially, or a topcoat is applied after the undercoat.

However, in such a coating method, the edge portions of the overlapping steel plates, which are once covered with paint during painting, tend to be exposed again during baking and hardening. This is one of the causes of early rusting in the market.

Therefore, for the purpose of preventing early rusting at the edges of steel plates, Japanese Patent Publication No. 59-156472 (Japanese Patent Application No. 58-31
No. 537), the surface of a steel plate is subjected to electrodeposition coating as an undercoat, and then the surface is plated. Although this anti-rust coating method is effective in preventing rust on the edges of steel plates, there is still the problem that the inner surfaces of bag structure parts such as rocker panels of automobile bodies are susceptible to rust. be.

For this reason, as a rust preventive treatment for the bag structure, (1) a method of injecting a rust preventive agent such as wax into the inside of the bag structure after electrodeposition coating to form a rust preventive film layer on the inner surface; (2); (3) A method in which the bag structure is formed from a rust-proof steel plate such as galvanized steel, and (3) a method in which after the undercoat is applied, a diffusing coating is applied with a rust-proofing paint to form a rust-proofing coating on the inner surface. ing.

[Problem that the invention seeks to solve]

However, in the above-mentioned rust prevention treatment method (1), although a thick rust preventive coating layer is formed around the area where the rust preventive agent is injected, it is often not possible to sufficiently apply it to areas far from the injected area. It is still not a sufficient rust prevention measure.In addition, regarding the rust prevention treatment mentioned in (2) above, not only does the rust prevention layer such as zinc plating peel off during press forming of the rust prevention steel sheet, but it also increases costs. Furthermore, in (3) above, it takes a lot of time to dip the object to be coated in anti-rust paint to form a rust-preventive film on the bag structure. There is a problem that sufficient rust prevention effect cannot be obtained.

Therefore, this invention was made to solve the above-mentioned problems, and after forming conductive electrodeposition 1111 on the surface and inner surface of an article having a bag structure, The purpose is to improve the rust prevention effect of articles having a bag structure by forming a plating layer, and to carry out rust prevention work in a short time without increasing costs.

[Means for solving problems]

That is, in the rust prevention treatment method for an article having a bag structure according to the present invention, when simultaneously applying rust prevention treatment to the surface and inner surface of the article having a bag structure, the article is immersed in an electrodeposition paint containing a conductive material. Conductive electrodeposition on the surface and inner surface of the article! ! ! A film is formed, and this electrodeposited film is baked and cured. Thereafter, the article is immersed in a plating solution to form a plating layer on the highly conductive electrodeposited coating formed on the surface and inner surface of the article.

Electrodeposition paints containing conductive materials include electrodeposition paints to which carbon is added at a rate of 5% to 10%;
Examples include commercially available conductive electrodeposition paints. Furthermore, the coating conditions and coating equipment for these electrodeposition paints do not need to be specially set; for example, the conditions and coating conditions for the commonly used coating methods using cationic electrodeposition paints or coating methods using anionic electrodeposition paints can be used. The device can be used as is.

In addition, as a plating solution for forming a plating layer on a conductive electrodeposited coating, conventional plating solutions can be used as they are, such as nickel plating solution, chromium plating solution, steel plating solution, etc. Examples include galvanizing solution, galvanizing solution, and the like. Among these plating solutions, zinc plating solution is the most excellent in terms of cost and coverage. Further, as the anode used in each plating solution, the same metal material as the plating solution is used, except that lead in the chrome plating solution is used. Furthermore, the plating conditions such as the temperature and current density of each plating solution and the plating apparatus can be the same as those normally used for each plating solution.

〔Example〕

Hereinafter, the method for anti-rust treatment of articles having a bag structure according to the present invention will be specifically explained with reference to Examples. However, the present invention is not limited only to these Examples, and the gist of the present invention will be explained in detail. Of course, various changes can be made within the scope of the invention.

(Example 1) Cold rolled steel plate with a plate thickness of 0.8 mm (JIS-G-3141,
5PCC) to form a rectangular parallelepiped-shaped box 1 as shown in the drawing. The size of this box 1 is 15 (1+s) in the vertical direction 2, 70 m in the horizontal direction 3, and 20 m in width.
A hole 5 of 0φ is formed.

Next, a zinc phosphate film of 3 glrd was formed on the surface and inner surface of Box 1 according to the commonly practiced pretreatment steps of alkaline treatment, water washing, chemical conversion treatment, and water washing. Thereafter, a conductive cationic electrodeposition coating film was formed on the surface and inner surface of the box 1 according to the electrodeposition coating method shown below.

Cationic electrodeposition coating method (1) Electrodeposition paint: Conductive cationic paint Carbon addition amount: --- 13 wt% Heating residue: --- 2 Qwt% Paint color: Blank (2 ) Painting conditions: Paint temperature - 25°C anode...
...Stainless steel cathode --- Box distance between electrodes ---150 Voltage between electrodes ---230v Current application time ----3 minutes (3) Average membrane Thickness: Surface side---15μm Inner side・
......7μm Next, box 1 on which the conductive electrodeposited coating was formed was washed with ionized water for 1 minute to remove the electrocoated paint that was physically attached. Water droplets on the electrodeposited film were removed by blowing heated air at a temperature of 40° C. at a flow rate of 1 m/sec for 3 minutes on the surface and inner surface of the electrodeposited film. Thereafter, this box 1 was baked and hardened for 20 minutes in a drying oven whose internal temperature was set at 180°C.

Then, a galvanized layer was formed on the highly conductive electrodeposition coating film of the obtained box 1 according to the electroplating method shown below.

Zinc plating method (1) Zinc plating solution (a) Zinc chloride ---200g/1 (b) Ammonium chloride ---240g/1 (2) Plating conditions (a) Liquid temperature ---40° C (b) Anode --- - Zinc (C) Cathode --- Box (d) Distance between electrodes --- 150 m5 (e) Current density --- = 3 A/d rd ( f)
Current application time: -10 minutes The obtained box 1 was washed with water and water droplets were removed in the same manner as after the cationic electrodeposition coating.

Thereafter, Box 1 was disassembled and the precipitation state of the galvanized layer on the surface and inner surface was observed. As a result, an electrodeposition coating film made of electrodeposition paint, which is rich in resin and has low conductivity, was formed on the surface of the box 1, and almost no galvanized layer was deposited. This is considered to be because the current density is high outside the box 1, so that a resin-rich electrodeposition coating film with low conductivity is actively formed.

In addition, a galvanized layer is formed on the entire inner surface of the box 1, and when measured with an electromagnetic film thickness meter, the zinc plating layer is between 2 and 1.
A galvanized layer of 0 μm was deposited. This means that
This is thought to be because the current density is low inside Box 1, so a highly conductive, pigment-rich electrodeposited film is actively formed.

(Example 2) A zinc phosphate film of 3 g/rrf was formed on the same box 1 as in Example 1 in the same manner as in Example 1.

Next, according to the same cationic electrodeposition coating method as in Example 1, a conductive cationic electrodeposition M coating film of 15 μm on the surface side of the box 1 and 7 μm on the inner surface side was formed. Thereafter, water washing and water droplets were removed in the same manner as in Example 1, and the electrodeposited coating was baked and cured.

Then, a copper plating layer was formed on the highly conductive electrodeposition coating film of the obtained box 1 according to the electroplating method shown below.

Copper plating method (1) Copper plating solution (a) Copper sulfate...220g/j' (b) Sulfuric acid...-55g/11 (2) Plating conditions Ca) Liquid temperature... -23°C (b) Anode - Copper (c) Cathode - Box (d) Distance between electrodes - 150 dragons (e) Current density - 111~- 3 A/d n (Cf") Current application time: 10 minutes The obtained test piece was washed with water and water droplets were removed in the same manner as in Example 1.

Thereafter, Box 1 was disassembled, and the state of precipitation of the copper plating layer on the surface and inner surface was observed. As a result, only a resin-rich electrodeposition coating with low conductivity was deposited on the surface of Box 1, with almost no copper plating layer deposited, but a copper plating layer of 4 to 9 μm thick was deposited on the inner surface of Box 1. was.

(Example 3) A zinc phosphate film of 3 g/rd was formed on the same box 1 as in Example 1 in the same manner as in Example 1.

Next, according to the same cationic electrodeposition coating method as in Example 1, conductive cationic electrodeposition with a thickness of 7 μm was applied to the surface of the box 10 (158 m1) and the inner surface of the box 10! ! ! A film was formed. Thereafter, water washing and water droplets were removed in the same manner as in Example 1, and the electrodeposited coating was baked and cured.

Then, a nickel plating layer was formed on the highly conductive electrodeposition coating film of the obtained box 1 according to the electroplating method shown below.

Nickel plating method (1) Nickel plating solution (a) Nickel sulfate --- 280 g/1 (b) Nickel chloride --- 45 g/1 (c) Boric acid ---
-40g/1 (2) Plating conditions (a) Liquid temperature - -50゛C (b) Anode - Nickel (c) Cathode - Box (d) Distance between electrodes - ---150fi (e) Current density ----4 A/d n ((f) Current application time ---10 minutes The obtained test piece was washed with water and drained in the same manner as in Example 1. Removed.

Thereafter, Box 1 was disassembled and the state of precipitation of the nickel plating layer on the surface and inner surface was observed. As a result, only a resin-rich electrodeposition coating with low conductivity was deposited on the surface of the box 10, and almost no nickel plating layer was deposited.
A nickel plating layer with a thickness of 3 to 6 μm was deposited on the inner surface of box 1.

(Comparative Example) A zinc phosphate film of 3 g/rd was formed on the same box 1 as in Example 1 in the same manner as in Example 1.

Next, according to the same cationic electrodeposition coating method as in Example 1, a conductive cationic electrodeposition coating film of 15 μm thick was formed on the front surface of the box 1 and 7 μm thick on the inner surface side. Thereafter, water washing and water droplets were removed in the same manner as in Example 1, and the electrodeposited coating was baked and cured.

A salt spray test was carried out on Box 1 obtained in Examples 1 to 3 and Comparative Example, and the time required for rust to occur was investigated, and the results shown in the following table were obtained.

Salt spray test: Based on the standard of JIS-Z-2371.

As is clear from the table, the time for rust to develop on the surface of the box is the same in Examples to 3, which are the rust prevention treatment methods of the present invention, and the comparative example, but the time for rust to develop inside the box is It was revealed that Examples 1 to 3 using the rust prevention treatment method of the present invention had rust prevention power 1.5 to 2 times that of the comparative example.

[°Structure of the invention]

As explained above, in the rust prevention treatment method for an article having a bag structure according to the present invention, conductive electrodeposition l! ! ! After forming 1111,
Since the plating layer is formed on the highly conductive electrodeposited coating, it is possible to significantly improve the rust prevention effect on the surface and inner surface of an article having a bag structure.

Further, in the rust prevention treatment method according to the present invention, there is no need to use an expensive rust prevention steel plate, so there is an effect that the rust prevention treatment can be performed without increasing the cost.

Furthermore, in the rust prevention treatment method according to the present invention, since the rust prevention treatment is performed using electrodeposition coating technology and plating technology, the surface and inner surface of the article having a bag structure can be treated for rust prevention at the same time. This has the effect that rust prevention treatment can be carried out in a short time.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a perspective view of a box used in the method for rustproofing an article having a bag structure according to the present invention. 1------・-Box

Claims (1)

[Claims] To simultaneously perform anti-corrosion treatment on the surface and inner surface of an article having a bag structure, the article is immersed in an electrocoated paint containing a conductive material to form a conductive electrocoated coating on the surface and inner surface of the article. After baking and curing the electrodeposition coating film, the article is immersed in a plating solution to form a plating layer on the highly conductive electrodeposition coating film of the article. Rust prevention treatment method for items held.