JPS5942804B2 - Rust preventive coating thickness measurement method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for measuring the thickness of a rust preventive coating.

J galvanized pipes are coated with a colorless and transparent rust preventive agent (acrylic resin) to prevent white rust (zinc hydroxide) from forming.

It is necessary to measure the paint film thickness for paint management, but because the base material to be measured is zinc, accurate measurement is not possible. Even if a precise film thickness meter such as an electromagnetic micro-thickness meter is used, the measured values vary widely and cannot be put to practical use. If the film thickness of the rust preventive agent is too thick, local accumulations (sag) of the rust preventive agent will occur on the pipe surface, impairing the appearance and causing a deterioration of the unit consumption.

On the other hand, if the film thickness is too thin, white rust may occur later, causing problems. Therefore, in order to control the film thickness of the rust preventive agent to an appropriate value, there has been a strong demand for establishing an accurate film thickness measurement method. An object of the present invention is to obtain a simple and accurate method for measuring the coating thickness of a rust preventive agent. The method of the present invention is characterized in that a test tape is attached to a dummy material, the material is fed into a rust preventive coating device, and the thickness of the test tape before and after coating is measured with a micrometer to calculate the film thickness.

Next, a method for measuring the thickness of a rust preventive coating based on the present invention will be explained with reference to the drawings.

First, select a dummy material (1) As the dummy material, any one of the galvanized pipes to be coated with a rust preventive agent may be scraped out.

Next, a test tape is attached to this dummy material (2) The O test tape has properties similar to the plating layer and has a rust preventive agent (
Any material may be used as long as it can withstand the chemical action of organic solvents). Examples of materials that meet these conditions include aluminum foil, nickel-based alloy foil, copper foil, and organic solvent-resistant resin tape. This test tape can be attached anywhere on the dummy material, but in order to find out the average value of the rust preventive coating condition, it is best to attach it to the center and the outer periphery of both ends of the dummy material. preferable.

The dummy material thus prepared is fed into the rust preventive coating device 3.

Here, the dummy material is coated with a normal rust preventive agent. Therefore, the rust preventive agent is applied on the test tape under the same conditions as on the surface of the dummy material. Next, collect the test tape from the dummy material (4) Since the O test tape is lightly attached to the dummy material, it can be easily peeled off.

Finally, the thickness of the test tape is measured using a micrometer (5). The film thickness of the rust preventive agent can be determined from the difference between this measured thickness and the previously measured thickness of the test tape.

For example, in galvanized electrical conduits for export, the coating thickness of the rust preventive agent is specified to be 7μ or more, and the coating is usually applied to ensure a thickness of about 1.5 to 2.0 times this specified thickness. There is.

In this case, by using an aluminum foil test tape with a thickness of about 17μ and measuring the painted tape with a micrometer with an accuracy of ±1μ, the coating thickness can be determined with sufficient accuracy. If the film thickness is within the desired range, the coating line is immediately started to perform normal coating.

If the film thickness is outside the desired range, adjust the setting device 6 of the rust preventive coating device 3 to change the coating conditions, and repeat the measurement method described above until it falls within the desired range. Repeat this series of operations. The main factors of the coating conditions are the supply flow rate, discharge pressure, and concentration of the rust preventive agent, and the feed rate of the material to be coated.

If the relationship between these factors and the coating thickness is determined in advance through numerous experiments, the coating thickness can be easily controlled. As is clear from the above description, according to the method of the present invention, the thickness of any type of rust preventive coating can be easily measured, and troublesome correction and adjustment of the instrument is not required.
Furthermore, problems such as white rust caused by uneven coating and insufficient coating thickness can be resolved.

[Brief explanation of the drawing]

The single drawing is a schematic illustration of a method for measuring the thickness of a rust preventive coating according to the present invention. 3... Rust preventive coating equipment

Claims (1)

[Claims] 1 Select any one of the materials to be coated as the dummy material, attach a test tape whose thickness has been measured in advance to a predetermined location on the dummy material, and send the dummy material to the rust preventive coating equipment. , a rust preventive coating characterized in that a test tape is taken from a painted dummy material, the thickness of the taken test tape is measured, and the coating film thickness is calculated from the difference between the measured value and the measured value. Film thickness measurement method.