US1878178A - Insulating composition - Google Patents

Description

"106. COMPOSITIONS,

comma on msnc (r088 Reference Patented Sept. 20, 1932 UNITED STATES PATENT OFFICE LAURENCE E. POWER, OF MILWAUKEE, WISCONSIN, .ASSIGNOR, BY MESNE ASSIGN- MENTS, T ALLEN-BRADLEY COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORA- TION OF WISCONSIN INSULATING COMPOSITION sulating lining is obtained at a considerably No Drawing. Application filed May 5,

This invention relates to certain new and useful improvements in insulating composireduced cost. tions and method of making the same, and The insulating composition is formed by refers more particularly to insulating comcombining two colloidal solutions which have Examiner positions for use as linings of electrical conthe charactertistics of thickening immediate- 55 troller housings, or cabinets; and is a conly upon contact with each other. The ingretinuation as to all common subject matter of clients of the two solutions are glue water an application filed September 29, 1926, Seand powdered mica for one, and a solution of rial No. 138,494. sodium silicate (water glass) as the other.

Heretofore, the walls of metal cabinets and These ingredients are in the following pro- 60 housings for electrical apparatus have been portions: protected by gluing sheet asbestos or the like Parts thereto, but this method is objectionable in Glue 7 that asbestos paper is not only expensive, but Water; 20

is costly to apply, and further its resistance Mica 5 65 to an electric arc is very unsatisfactory. odium silicate 5 It is therefore, an object Of this invention Ordinary commercial grade) to provide an improved insulating composition which is comparatively cheap, easily applied as a lining for cabinet walls, and which offers excellent resistance to the destructive forces of an electric arc.

Another object of this invention resides in the novel method of making the insulating composition, whereby an immobile substance is formed by a colloidal precipitation in two fluids brought together at the time of application.

And a further object of this invention resides in the formation of an immobile insulating composition of two solutions having the characteristic of thickening immediately upon contact with each other.

The present conventional manner of insulating the interior wall surfaces of metal cabinets for switches and other electric apparatus, is to line the same with asbestos and have been found from experience to withstand the arc test in a very satisfactory manner, and will not show a tendency to run during application, irrespective of the inclination of the surface.

The proportions given above may be varied considerably and still produce excellent results, as it is difficult in actual practice where the materials are sprayed separately, to maintain the exact proportions between the glue, water and mica and sodium silicate. It is desirable, however, to avoid a large excess of sodium silicate over that which is necessary to produce the desired increase in viscosity, as sodium silicate is not a good insulator at high temperatures.

The glue employed in the above solution is formula a or. While this manner of lining cabinets hasbeen in vogue for many years and meets $3, 3 glue-16 to 18 cent grade" with the approval of the board of under- Glucose 20 writers, it is open to many serious objectio s G1 Germ; 30 such as the inability of asbestos paper to g g'g "a 8 satisfactorily resist an electric arc and also that it is very expensive to apply, both from the standpoint of material and labor.

This invention. therefore, contemplates the elimination of the cumbersome manner of lining cabinets heretofore used, by applying an improved insulating composition directly to their interior walls, wherein a better inalthough it is to be understood that any glue capable of providing the necessary adherence may be used. The mica employed is preferably a 200 mesh.

In forming the glue solution, the glue and water are first mixed and then the powdered mica is thoroughly stirred therein.

preferably made according to the following/ a If it is desired to apply the composition by means of a brush, its viscosity, which increases immediately with the combining of the two solutions due to a precipitation of colloids, may be lowered by heating the same to a working temperature somewhere in the neighborhood of 160 degrees Fahrenheit.

However the more preferable method of applying the composition is to spray the two solutions simultaneously so that the two streams meet and co-mingle just prior to striking the surface being coated.

This manner of application greatly facilitates the lining of the surfaces as the solutions retain their fluid state until the actual application. Any manner of spraying the solutions may be employed but the method described in a copending application Serial No.

388,542, filed August 26, 19:29, is deemed preferable. As described, in this application, two conventional spray guns are connected in such a manner that the sprays emitted therefrom meet at a point slightly spaced from the guns, each gun being connected with a receptacle containing one solution.

From the foregoing description it will be readily apparent to those skilled in the art to which an invention of the character described appertains that I provide an improved insulating composition which may be very economically and effectively applied to a wide variety of uses, and which provides an insulation capable of withstanding destructive arcing forces.

What I claim as my invention is:

1. An insulating composition comprising a precipitate of seven parts glue, 20 parts water, five parts mica. and sodium silicate.

2. An insulating composition comprising a precipitate of seven parts glue, twenty parts water, five parts mica, and five parts sodium silicate.

3. An electrical insulating composition capable of withstanding high temperatures without damage, comprising the precipitate of a mixture of glue including animal glue, glucose, glycerine and soluble oil, water and mica, with sodium silicate.

In testimony whereof I have hereunto affixed my signature.

LAURENCE E. POWER.