JPS6068081A - Coating method - Google Patents

Abstract

PURPOSE:To form efficiently a coated film without unevenness on the surface of a material to be coated by dipping said material into a paint to which an ultrasonic wave is impressed. CONSTITUTION:A paint 2 is put into a coating tank 1 and a material 3 to be coated is put therein and is vertically moved, by which the paint is coated thereon. In the figure 4 denotes a cover and a 5 a valve for discharging the paint. An ultrasonic vibrator 6 is attached in the lower part of the tank 1 and an ultrasonic oscillator 7 is connected thereto. An ultrasonic wave is impressed to the paint for about 30sec-2min to oscillate the paint and thereafter the ultrasonic wave is stopped and the material to be coated is dipped in the paint in the case of coating the paint thereto. The ultrasonic wave is again impressed when the material is pulled up at a prescribed speed. The reason for stopping the ultrasonic wave during immersion of the material to be coated into the paint is because the surface of the paint liquid waves during impression of the ultrasonic wave.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method in which ultrasonic waves are applied to a paint.

Dip coating methods have been widely used in the past, in which the paint is deposited on the surface of the workpiece by dipping the workpiece into the paint and then pulling it out. In the method described above, if the paint is uniform in the coating tank containing the paint, a uniform paint film will be formed, but if the paint is uneven, the paint film will also be uneven. Unevenness in the paint may include uneven concentration, uneven composition, etc. If the paint is a pigment dispersion system,
Further examples include uneven pigment particle size, uneven agglomeration, and color separation.

In order to prevent paint unevenness, it is sufficient to constantly stir or fluidize the paint, but this alone is not sufficient, and pigment dispersion systems in particular tend to cause unevenness. Moreover,
Since the dip coating method is greatly influenced by the surface condition of the paint liquid, even the slightest unevenness is undesirable.

The present invention aims to reduce such unevenness of the paint as much as possible, and is characterized by using ultrasonic waves as a means for effectively vibrating the paint.

Ultrasonic waves have been used in the past, such as in ultrasonic cleaners, which forcibly vibrate solutions and equipment, and dispersers, which have the effect of breaking up particles, and are effective in vibrating paint. is very effective. In the dip coating method, the present invention applies ultrasonic waves to the paint to vibrate the paint, thereby making the paint uniform and forming a uniform and clean paint film on the coated object. can. Ultrasonic waves can be generated by electrically applying an alternating current signal of a frequency corresponding to ultrasonic waves to an ultrasonic transducer. The frequency is usually 18 to 50 KHz.

The application of ultrasonic waves will be specifically explained with reference to drawings and examples.

Example 1 FIG. 1 shows an example of applying ultrasonic waves to a coating tank for dip coating. A paint 2 is placed in a coating tank 1, and an object 3 to be coated is placed therein and applied by being moved up and down. 4
5 is the pulp for discharging the paint. An ultrasonic vibrator 6 is attached to the bottom of the coating tank, and an ultrasonic oscillator 7 (manufactured by Kaiyo Denki ■, output 100 W) is connected to this.

The coating method involves applying ultrasonic waves for about 30 seconds to 2 minutes to vibrate the paint. Next, the ultrasonic wave is stopped, the object to be coated is immersed in the paint, and then pulled up at a predetermined speed. When the object to be coated is lifted up, ultrasonic waves are applied again.

The reason why the ultrasonic waves are stopped while the object to be coated is immersed is because the surface of the coating liquid becomes rippled during the application of the ultrasonic waves.

Example 2 FIG. 2 shows a coating method in which paint is circulated between a coating tank and a coating tank provided separately from the coating tank. In this method, the paint always overflows from the top of the coating tank, so there is no fluctuation in the coating liquid level and a fresh surface is always obtained, making it a very suitable method for dip coating.

The object 3 to be coated is raised and lowered by the coating material 2 in the coating tank 1 in the same manner as in the example shown in FIG. The paint 2 overflowing from the top of the coating tank 1 is collected by a tray 13 and returned to the paint tank 14 by a hose 12. The paint 2 in the paint tank 14 is pressurized by a pump (magnetic pump manufactured by Iwaki ■) 8, and sent to the aeration coating tank 1 through a filter 9 for removing dust (Tocel filter manufactured by Toyo Tamashi ■).

Ultrasonic waves may be applied to the coating tank, but in this case, the ultrasonic waves must be intermittent as in Example 1, so the application was made to be applied to the paint tank 14 as a location other than the coating tank. .

The coating method involves applying ultrasonic waves and operating the pump 8 to circulate the paint 2. In this state, the object 3 to be coated is dipped into the paint 2, and then pulled up at a predetermined speed.

By applying ultrasonic waves to a single paint as in the present invention, it is possible to prevent the occurrence of unevenness in the paint, and in the case of pigment dispersion paints, it is possible to eliminate agglomeration and sedimentation of pigments. A very uniform and clean coating film was obtained.

[Brief explanation of the drawing]

FIG. 1 shows an example of applying ultrasonic waves to the paint in a coating tank, and FIG. 2 shows an example of applying ultrasonic waves to the paint at a location other than the coating tank. The symbols in the diagram are 1... Application tank 2... Paint 3... Object to be coated 4... Lid 5... Pulp 6... Ultrasonic vibrator 7... Ultrasonic oscillator 8...Pump 9...Filter 10...
・Pulp 11... Hose 12... Hose 13... Paint receiver is a tray 14... Shows a paint tank. Patent applicant Canon Co., Ltd. Agent Patent attorney Yu Kano

Claims (4)

[Claims] (1) In the dip coating method, which involves immersing the object in the paint and then pulling it up, applying ultrasonic waves to the paint is used to form a coating film on the surface of the object. Characteristic application method. (2) The coating method according to claim 1, wherein ultrasonic waves are applied to the paint placed in a coating tank. (3) Claim 1, which includes a step of continuously circulating the paint between paint tanks provided separately from the application tank, and applying ultrasonic waves to the paint at a location other than the application tank. Application method as described. (4) Claim 1 in which the paint is a pigment dispersion paint
2. The coating method according to item 2 or 3.