JPS62122006A - Electrical insulating molded unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrically insulating molded article that does not use asbestos.

Arc shielding plates used in blow-out type circuit breakers are not only arc resistant but also heat resistant.

It is also required to have excellent mechanical strength.

Conventional electrical insulating materials with such properties include:
Asbestos-based materials have been widely used.

For example, "
Arc-resistant electrical insulating materials have been used for a long time as materials with the above characteristics.

However, asbestos is one of the carcinogenic substances, and regulations on its use have been tightened in recent years.

Therefore, the emergence of so-called "asbestos-free" electrical insulating materials that do not use asbestos has been desired, and materials with various compositions have already been proposed. However, the asbestos-free materials proposed so far are
It is inferior to asbestos-based materials in either electrical properties such as arc resistance, heat resistance, mechanical properties, etc., and no material comparable in quality to asbestos-based materials has yet been obtained.

Means for Solving the Problems As a result of various studies conducted in view of the above-mentioned current situation, the present invention uses Seviolite, acicular talc, and aluminum oxide as insulating base material components instead of asbestos, and also uses as a binder. It has been found that when orthophosphoric acid is used, an electrically insulating molded article having physical properties equivalent to or better than conventional asbestos-based materials can be obtained. That is, the present invention uses till orthophosphoric acid to 40 parts by weight to a total of 100 parts by weight of [l1fa) 100 parts by weight of sepiolite, 20 to xooozz parts of TBL acicular talc, and (c) 50 to 800 parts of aluminum oxide. Concerning the blended electrically insulating molded body.

Sepiolite is a porous fibrous hydrous magnesium silicate mineral that occurs as a secondary mineral in serpentinite, and its ideal composition is Mg g (H2O)4■U, 8iu pseudo2-na2o. In the present invention, the fiber length is 5 to
A fiber having a fiber diameter of about 50 μm and a fiber diameter of about 0.1 #m or less is preferably used.

Talc is Mg8Si40. (OH)2(D RiRMi
It is a hydrous magnesium silicate mineral (secondary mineral) having Fft. The acicular talc (also called fibrous talc) used in the present invention has a length of about 10 to 15 μm and a diameter of 1
A thickness of approximately 2 μm is preferable.

Any crystalline form of aluminum oxide can be used. The particle size is preferably about 10 to 150 m, more preferably about 80 to 5011 m.

In the present invention, as insulating base material components, the weight ratio of sepiolite:acicular talc:aluminum oxide = 100
:20-1000 :50-800 (Used at a ratio of 0.If any one of the three components falls outside the above range, any of the heat resistance, water absorption, electrical properties, mechanical properties, etc.) In this case, the desired performance cannot be obtained.Insulating base material components include sepiolite:acicular talc:aluminum oxide=100:40-500:90-400
It is more preferable to set the ratio to .

In the present invention, 5 to 40 parts by weight, preferably 10 to 20 parts by weight of orthophosphoric acid is blended as a binder with respect to all 100 M of the above-mentioned insulating base material component.

If the ratio (1) of orthophosphoric acid to 100 parts by weight of the insulating base material component is less than 5 parts by weight, the density of the molded article will be low. On the other hand, when the combined amount of orthophosphoric acid exceeds 40 parts by weight,
The resulting molded product will have poor arc resistance and electrical insulation under high humidity. In the present invention, if a phosphoric acid other than orthophosphoric acid is used as a binder, the desired effect will not be fully achieved.

The insulating base material component 100
The amount of zinc borate may be 2 to 15 parts by weight based on the weight part. The addition of zinc borate further improves the electrical insulation and water resistance of the molded article.

The electrically insulating molded article according to the present invention is produced by uniformly kneading the insulating base material component and orthophosphoric acid, for example, from 100 to 800 Kl/
After molding into a predetermined shape with a pressure of about cm2, it may be hardened.

Effects of the Invention The electrically insulating molded article obtained by the present invention exhibits excellent performance equivalent to or better than asbestos-based materials in electrical properties such as crucible arc properties, water absorption, heat resistance, mechanical properties, etc. Therefore, it is extremely useful as a new asbestos-free and highly safe material.

EXAMPLES Examples and comparative examples will be shown below to further clarify the characteristics of the present invention.

Examples 1 to 8 Each raw material was blended in the proportions shown in Table 1, molded, and the resulting molded product was dried at 250°C for 10 hours to remove moisture in the molded product, and various tests were conducted. Ta. The results are shown in Table 2.

The arc resistance was measured in accordance with JIS K 6911, and was determined by continuously generating an arc at a maximum current of 40 mA and measuring the arc maintenance time of the test piece up to 600 seconds.

In addition, the strength of insulation resistance, volume resistivity, surface resistivity, and water absorption were determined according to JIS K 6911 (Testing method for thermosetting plastics).

Comparative Example 1 Commercially available asbestos cement board for electrical insulation CJI8C2210A
Regarding OI), the same tests as in Examples 1 to 8 were conducted.

The results are also shown in Table 2.

From the results shown in Table 1, Table 2, and Table 2, it is clear that the electrically insulating molded article according to the present invention has excellent performance.

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Claims (1)

[Claims] (1) (I) (a) 100 parts by weight of sepiolite, (
An electrically insulating molded article containing 5 to 40 parts by weight of (II) orthophosphoric acid to a total of 100 parts by weight of b) 20 to 1000 parts by weight of acicular talc and (c) 50 to 800 parts by weight of aluminum oxide.