JPS581986B2 - Application method - Google Patents

Description

[Detailed description of the invention] In a coating method in which a solid surface is coated with powder such as a polymer substance, a powder layer is created on the surface of a liquid placed in a liquid tank, and the solid is first immersed in the liquid placed in the liquid tank. The present invention relates to a method of applying powder to a solid surface by passing the powder through a bed of powder.

Conventionally, in order to apply powder to a solid, there are methods of dissolving or dispersing the powder in a solvent or dispersant and applying a liquid, and methods such as electrostatic coating, fluidized bed dipping, spraying, and thermal spraying. It is broadly divided into methods such as direct spraying.

However, when applying in liquid form, it is necessary to diffuse the solvent and dispersant, which requires a large amount of solvent and thermal energy for drying.

In addition, when applying powder directly, the powder does not adhere only to the solid material to be coated, but a large amount is scattered, and in order to increase the adhesion efficiency, it is necessary to apply a large Both methods require equipment, are uneconomical, and have the disadvantage of polluting the environment.

In the present invention, as shown in FIGS. 1 and 2, a liquid tank 1,
The solid 3 of the material to be coated, which is immersed in the liquid 2 placed in the liquid 1', is passed through the powder layer 4 of the material to be coated on the surface of the liquid 2, and the powder is applied to the surface of the solid 3 taken out. This is a method of applying powder 5 of layer 4.

That is, first a very small amount of liquid 2 adheres to solid 3, and then powder 5 adheres via this liquid 2.

At this time, the powder 5 and the solid 3 need only be materials that are not easily dissolved, decomposed, degraded, or altered by the liquid 2.

The principle of the present invention is to utilize the interfacial phenomenon due to the mutual interfacial energy between the powder 5, the liquid 2, and the solid 3.

Therefore, the surface condition of each type of solid 3 and powder 5, such as roughness, shape, functional groups on the surface, liquid silk formation, liquid temperature,
The thickness of the suspended powder layer 4, vibration, bubbling, etc. are factors that influence the thickness and uniformity of the coated powder 5 film.

Next, a concrete explanation will be given using an example of implementation.

Figures 1 and 2 show powder of the material to be coated, in which the solid 3 of the substance to be coated, which has been immersed in the liquid 2 previously placed in the liquid tank 1, is floating on the surface of the liquid 2. It passes through the body layer 4 and is pulled up vertically above the liquid level by a lifting device (not shown).

If the solid 3 is long, if it is pulled upward through a liquid-tight seal packing (not shown) at the bottom of the liquid tank, the liquid 2 will first adhere to the surface of the material to be coated, and then the liquid 2 will be applied. Since the powder 5, which is the coating material, is attached via a small amount of liquid 2, continuous work is possible, and since the powder 5 and liquid 2, which are the coating materials, are used only for coating, there is no waste. .

Continuous operation is also possible by using the second tank 1' which does not contain the powder layer 4 and allows only the liquid 2 to communicate with it.

Since the powder 5, liquid 2, and solid 3 have mutually different interfacial phenomena, the selection of each is extremely important.

Furthermore, when the powder 5 having a uniform particle size is used, the coating film obtained will have a uniform thickness.

In addition, applying treatments such as blast treatment, thermal spraying, and etching to the solid material to be coated in advance improves adhesion and improves the liquid composition of rust preventive liquids, etching liquids, chemical treatment liquids, undercoat liquids, etc. Another effective method is to use

Next, an example will be described.

Example: Add 30 ml of ion-exchanged water to a 500 ml glass beaker.
Perfluoroalkoxy resin powder (average powder diameter 35 μm) was suspended on the surface of this ion-exchanged water to form a suspended powder layer of approximately 3 mm, which was degreased with trichlorethylene. Width 60 mm x length 90 mm x 2m thick
m 2S aluminum plate or ISS41 steel plate, or SU
A S304 stainless steel plate and a copper wire with a diameter of about 1 mm were passed through the suspended powder layer from the ion exchange water side.

That is, each substance to be coated is passed through an interface between ion-exchanged water and perfluoroalkoxy resin powder, and the perfluoroalkoxy resin powder is applied to the surface of each substance to be coated via a small amount of ion-exchanged water. After that, it was baked for 30 minutes in an electric furnace set at 350°C.

After baking, the coating was left to cool outside the oven, and the thickness of the coated film was measured. As shown in the table, an extremely uniform film was obtained.

The temperature of the ion-exchanged water at this time was 40°C, and the passing speed, that is, the pulling speed of the perfluoroalkoxy resin powder layer was 1 cm. /S.

From the values in the table, it can be seen that the film thickness obtained varies depending on the material to be coated.

This is because the interface between the ion-exchanged water and the solid material to be coated differs depending on the material to be coated.

Similarly, if the coating material is different, the resulting film thickness will be different.

As described above, the present invention provides a uniform powder coating film that prevents consumption of large amounts of solvents and dispersants during liquid coating and scattering of large amounts of powder during powder coating, making it inexpensive and effective for environmental protection. The purpose is to manufacture rationally.

[Brief explanation of drawings]

FIG. 1 is a plan view of an apparatus for a coating method according to the present invention, and FIG. 2 is a sectional view taken along lines A and A' in FIG. 1, 1'...Liquid tank, 2...Liquid, 3.
...Solid, 4...Powder layer, 5...
·powder.

Claims (1)

[Claims] 1. An application method in which a solid that has been immersed in a liquid in advance passes through a layer of powder floating on the surface of the liquid, thereby applying powder to the surface of the solid.