JPS5984959A - Production of heat insulating coating - Google Patents

Abstract

PURPOSE:To prepare a heat insulating coating having insulating properties, mechanical strength, and uniform thickness on the surface of a conductor to be coated, by immersing the conductor to be coated in a coating compound of electrodeposition containing mica powder, water dispersion varnish, and a fibrous material, subjecting it to electrophoresis. CONSTITUTION:The conductor 1 to be coated is immersed in a coating compound of electrodeposition containing preferably (A) 100pts.wt. of the mica powder 4, (B) 5-50pts.wt. of the water dispersion varnish 5, and (C) 1/200-1/10 the amount of the components A+B of the fibrous material 6 (preferably glass fibers, or organic fibers having 0.001-0.01mm. major axis and 0.5-10mm. length), an electrodeposition layer is formed on the surface of it by electrophoresis, heated and dried, to give a heat insulating coating. EFFECT:Since a heat insulating coating is prepared even on a conductor having a complicated shape, automation and reduction in labor can be possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing thermal barrier coatings using electrophoresis.

In more detail, conductors that require heat retention or heat shielding are immersed in electrocoated paint containing mica powder, water-dispersible varnish, and fibers, and conductors that require heat retention or heat shielding are coated using electrophoresis. The present invention relates to a method of forming an electrodeposited layer mainly composed of mica e on the surface of the present invention.

Conventional methods for producing heat insulating layers for equipment or parts that require heat retention or insulation include methods of attaching a porous layer such as felt by wrapping or pasting, methods of applying a coating material to the surface of the object to be coated, or A commonly known method is to form short fibers on the surface of an object by flocking.

However, the conventional method of applying a porous layer by wrapping or pasting requires a lot of labor and is difficult to apply to objects with complex shapes. The method of coating on the surface has drawbacks such as difficulty in improving the uniformity of the coating film.

As a result of intensive research to eliminate the drawbacks of the conventional methods, the present inventors have found that conductive coatings that require heat retention or heat insulation can be coated in electrocoated paints containing mica powder, water-dispersible varnish, and fibers. By immersing the conductor, forming an electrodeposited layer on the surface of the conductor by electrophoresis, and then heating and drying it to form a heat-insulating film, the above-mentioned defects can be removed, and the heat-insulating property, mechanical strength, and optional properties can be improved. The present invention was completed based on the discovery that it is possible to easily obtain a heat-insulating coating with good uniformity at a thickness of 1,000 yen, and that the process can be automated and labor-saving relatively easily.

The mica powder used in the present invention is preferably natural mica, and the powder diameter of the mica powder does not pass 200 mesh.
One that passes through a mesh, preferably one that passes through 65 meshes, is used.

The water-dispersible varnish used in the present invention acts as a binder between the mica powder and the fibers in the electrodeposited layer, and any type of water-dispersible varnish can be used, such as acrylic. Thread varnish, epoxy thread varnish, etc. can be used without any limitation.

The blending amount of mica powder and water-dispersible varnish used in the present invention is preferably 5 to 50 parts of water-dispersible varnish resin per 100 parts of mica powder (parts by weight, hereinafter the same), and less than 5 parts is suitable for electrodeposition. The moisture content of the precipitated layer becomes high, causing the precipitated layer to run down, and if it exceeds 50 parts, the mica content in the precipitated layer becomes low, resulting in a decrease in heat insulation properties.

The inorganic fibers or organic fibers used in the present invention serve as reinforcing materials for the electrodeposited layer, and from the standpoint of reinforcing materials, it is preferable that they be as thin and long as possible; however, the appearance of the electrodeposited layer and Taking into consideration the prevention of tangles of the fibers when stirring the electrodeposition paint, the major diameter is 0.001 to 0.01 m.
m, and a length of 0.5 to 10 mm is suitable. The content of the inorganic fibrous body or the organic male body is preferably 1/200 to 1/10 of the total weight of the mica powder and the water-dispersible varnish resin. If the content of the fibrous body is less than 1/200, the insulation and mechanical strength of the electrodeposited layer will be insufficient;
If it exceeds /10, the heat insulation properties are good, but the viscosity of the electrodeposition paint increases too much.

Mica powder and water-dispersible varnish particles are negatively charged in the electrodeposition paint solution using the above-mentioned materials, and migrate to the object to be coated, which is the anode, during electrodeposition. The fibers, which are not electrically charged and are difficult to migrate, are also deposited as an electrodeposited layer.

In order to improve the migration properties of the fibers, it is also effective to adsorb a surfactant or treat them with a coupling agent.

Even if the equipment or parts that require heat retention or heat insulation have a complex shape, a heat insulating coating can be easily formed.
Moreover, by changing the electrodeposition conditions (electrodeposition voltage or time), a uniform heat-insulating coating of any thickness can be obtained. Incidentally, electrodeposition can be easily carried out using known techniques, and automation and labor saving can be relatively easily carried out in the present invention.

Next, the present invention will be explained in detail with reference to reference examples and examples.

Reference example 1 Ebiko zool (manufactured by Shell Chemical Co., Ltd.) 200 (Hl,
Ethylene glycol 1009, tetrahydrophthalic anhydride 460g and xylene 250g were placed in a 51-4-metre flask and reacted at 145 to 15000 for about 1 hour while passing hydrogen through it to obtain an acid-added epoxy resin with an acid value of about 50.

Place lauryl sulfate soda 7, o9 and ion exchange water 35009 in a 51 Yotsuro flask, heat with stirring, and prepare a 25% ammonia aqueous solution 10 at 65-70'O.
0g and the above acid-added Evokire resin 5009 were added and emulsified, and stirred at 70"O for about 5 hours while distilling off excess ammonia and water through an inert gas (nitrogen gas). Approximately 7.5 epoxy water i
Sex varnish (emulsion) (5) I got it.

Example 1 Mica powder (4) passing through 35 meshes thoroughly washed with ion-exchanged water in the water-dispersible varnish (5) obtained in Reference Example 1
7 parts per 60 parts of nonvolatile content of the water-dispersible varnish (5).
Further, 1 part of glass fiber which is an inorganic fiber (6) having a diameter of 0.005 mm and a length of im is mixed in at a ratio of 0 parts, and ion-exchanged water is added and stirred well to obtain a total non-volatile content of 2.
A 0% electrocoating paint was prepared.

The object to be coated (piping (1) in Figure 1) that requires heat insulation is immersed in the electrodeposition paint, and a DC power source (100V) (8) is connected between the electrodes and the opposite electrode with a distance of 50 am between the electrodes. The application was applied for about 20 seconds to form an electrodeposited layer consisting of mica powder, water-dispersible varnish resin, and glass fiber on the surface of the object to be coated.

Then, it was heated and dried at 150°C for 15 minutes to form a heat insulating layer.

The heat insulating layer was changed to a uniformly formed layer including the 7 rungs.

[Brief explanation of the drawing]

Figure 1 is a perspective view of piping for transferring low-temperature or high-temperature liquids;
The figure is a partially cutaway perspective view of a piece that has been heat-insulated by the conventional method, Figure 6 is an explanatory diagram to explain the electrodeposition treatment method of the present invention, and Figure 4 is a perspective view of a piece obtained by the method of the present invention. FIG. 2 is a partially cutaway perspective view for explaining a heat insulating layer. (Main symbols in the drawing) (2): Heat insulating coating (3): Binding layer (4): Mica powder (5): Water-dispersible varnish (6): Fibrous body (γ): Electrodeposition treatment tank agent Kuzuno Communication (1 person) Figure 1 Figure 3 Figure 4

Claims (6)

[Claims] (1) The entire conductor to be coated that requires heat retention or heat shielding is immersed in an electrodeposition paint containing mica powder, water-dispersible varnish, and fibrous material, and the conductor to be coated is electrodeposited on the surface of the conductor to be coated by electrophoresis. A method for producing a heat insulating coating, which comprises forming a precipitated layer and drying it by heating. (2) The method for producing a heat-insulating coating according to claim (1), wherein the electrodeposition coating uses a mixture of 100 parts by weight of mica powder and 5 to 50 parts by weight of a water-dispersible varnish resin. (3) In the electrodeposition paint, the fiber body is 1/20 D to 1 of the total weight of the mica powder and the resin content of the water-dispersible varnish.
/10 Claim No. (1)
2. Method for producing a heat-insulating coating as described in Section 1. (4) As a fibrous body, the major axis is 0.001 to 0.01 mm,
A method for producing a heat insulating coating according to claim 1 or 3, wherein a heat insulating coating having a length of 0.5 to 10 mm is used. (5) Claim No. 1 in which the fiber body is glass fiber
) The method for manufacturing the heat insulating coating described in item 2. (6) Claim No. (1) in which the fibrous body is an organic fiber
2. Method for producing a heat-insulating coating as described in Section 1.