JPS5951082B2 - Inorganic insulation material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present chewing material contains various refractory insulating materials such as siliceous refractories, waxite refractories, chamocite refractories, holsterite refractories, asbestos, etc. as main components, and has excellent properties. The present invention relates to an inorganic insulating material having good electrical properties (insulation resistance) and water repellency.

In some cases, electric component materials such as heating wires are embedded or enclosed in an insulator, such as in electric heaters.

However, when used in a high-humidity atmosphere or when water is accidentally splashed onto the surface of the insulating material, moisture may adhere to the insulating material due to the surrounding environment or troubles, causing electrical properties to deteriorate. In particular, there were problems such as a significant decrease in insulation resistance and current leakage. To prevent this phenomenon, the surface of the refractory insulation material is generally coated by adding water-repellent synthetic resin, such as silicone resin, thereby blocking it from atmospheric humidity or water. Treatment methods for preventing deterioration of insulation properties are known. In addition to silicone resin, epoxy resin,
Methods of surface treatment with polyester resin are also used, and various improvements have been made to these resin coating methods. For example, methods include vacuum impregnating an insulating material with these synthetic resins, removing the remaining synthetic resin from the surface of the impregnated material, and then curing the impregnated resin. Since it uses an organic substance, it has the drawback that, for example, it scatters or carbonizes when the temperature is high. A phosphoric acid treatment method is also used, but this method does not significantly improve insulation properties. Regarding electrically insulating glass materials, water glass has been used as a binder to prevent deterioration in insulation in a high humidity atmosphere, but this has not been sufficiently effective.

The present invention solves the above-mentioned problems, and aims to provide an excellent insulating material that absorbs less moisture and exhibits less insulation deterioration even when left in a high humidity atmosphere for a long time.

The present invention uses SiO.

-MgO-Al. Add 0.05 to 5% by weight of fine powder of polycarbon monofluorado (CFx)n, which has high water repellency, to refractory powder such as O, etc., and mix well. It is characterized in that it is coated with Florard and used as an inorganic electrical insulating material by being molded and filled as needed. The polycarbon monofluorade used in the present invention has strong water repellency to water or aqueous solutions, for example, the contact angle to water is 1500 and 180 after 100 hours, and Mg
0.05 and 0.05% of polycarbon monofluorade to O, respectively.
025, 0.5, 1, 2 and 5% by weight were mixed and observed to be floating on water, no sedimentation occurred at all.

Similarly, the same experiment as above was conducted using silicone resin (contact angle 90-1000), but some of the MgO precipitated. Therefore, it can be seen that the water repellency is considerably stronger than that of silicone resin5. In addition, regarding heat resistance (thermal decomposition temperature), the silicone resin used in this experiment decomposes at temperatures above 350°C.
Polycarbon monofluorade decomposes at temperatures above 430°C, so it has considerably better heat resistance than conventional synthetic resin coatings.

Insulating materials obtained by coating the surface of refractory insulating materials with polycarbon monofluorade, which has these characteristics, have significantly improved insulation properties and hygroscopicity even when left in a high-humidity atmosphere for a long time. Ru.

Therefore, it is possible to exhibit the original characteristics of refractories, and by adding the above-mentioned characteristics, it can be effectively used in heating plates with embedded heating wires, etc. Next, embodiments of the present invention will be described.

SlO268% by weight, MgO22% by weight, Al2O34
Weight%, Fe2O32% by weight, others (CaO, Na2
0.5% polycarbon monofluorade fine powder to a finely powdered refractory insulation material having a chemical composition of 4% by weight (O, etc.)
% by weight was added and mixed well to coat the surface of the refractory material, which was then molded into a pellet having a diameter of 50 mmφ and a thickness of 5 mm.

This is designated as A, and as a comparative example, a state in which no polycarbon monofluorade is added, that is, a molded product made of refractory material alone is designated as B. The changes in insulation resistance over time of both samples at a relative humidity of 90% were compared. The results are shown in Figure 1. As is clear from this figure, it can be seen that the material according to the present invention has significantly improved insulation properties compared to the material without the addition of polycarbon monofluoride. Further, pellets prepared in the same manner were immersed in water at 20°C, and then the insulation resistance was measured.

The results are shown in FIG. As is clear from this figure, it is clear that the material obtained according to the present invention has significantly improved insulation properties compared to the material without the addition of polycarbon monofluoride. Note that the examples were carried out with the addition amount of polycarbon monofluorade at 0.5% by weight, but
Almost similar results were obtained in the range of 0.05 to 5% by weight. In addition, in the example, SlO2-MgO-A
Although we are conducting experiments using l2O3-based refractories, other fireproof insulating materials such as siliceous refractories, waxite refractories, schaumite refractories, holsterite refractories, or stone wire may also be used. Almost the same results as above were obtained.

[Brief explanation of the drawing]

Fig. 1 shows a comparison of changes in insulation resistance over time when the insulating material is left in an atmosphere of 25°C and R-H9O%, and Fig. 2 shows a comparison of insulation resistance after being immersed in water.

Claims (1)

[Claims] 1. An inorganic insulating material made by adding polycarbon monofluorade to a refractory insulating material.