US1123985A - Insulating material. - Google Patents

Description

* glass.

rninnnrcn BoLLmG, or oBnnunsE'L, GERMANY, assrenoa or ONE-HALF TO THE FIRM or PROMETHEUS FA .BRIK ELEKTRISCHER KOCH; nun HEIZAPPARATE, GESELLSCHAFT MIT BESGI-IRANKTER HAFTUNG, or -FRA1\TKFORT-ON-THE-MAIN,

Patented Jan. 5, 1915.

GERMANY.

INSULATING MATERIAL.

1,123,985. Specification 0f Letters Patent. No Drawing.

To all whom it may concern Be it known that I, FRIEDRICH Bonmnc, engineer, citizen of Germany, and resident of Oberursel, near Frankfort-on-the-Main, Germany, have invented certain new and useful Improvements in, Insulating Materials, of which the following is a specification. 1

My invention relates to a process for manufacturing heat proof, electric insulating blades, plates, etc from mica waste and the like. I 1 r It is known to produce electric insulating blades, plates, etc., from mica waste, flake mica, split mica, mica powder and the like, thesematerials being far cheaper than the natural mica, the price of which is constantly increasing, so that it becomes almost prohibitive for certain articles.

The mica Waste or the like is united to bodies of the form required by using a binding agent and subjecting the mixture to high pressure and high temperature at the same time. The binding agents which have been used or suggested consist of shellac and other carbonaceous materials or of water- All these binding agents can however only be employed, if the insulating bodies so made are not to withstand temperatures higher than say about 150 C. At higher temperatures the carbonaceous materials become softand charred, develop malodorous vapors and lose their binding and insulating capacities. Waterglass on the other hand gives up its water at said temperature and disintegrates into the form of a powder which no longer possesses any binding qualities and absorbs moisture from the atmosphere, thus unfavorably affecting the insulating properties of themica bodies to be produced.

Now, on the contrary to the methods referred to before, my process has for its object the manufacture of electric insulating blades, plates, etc., from mica wasteand the like, whichare capable of withstanding temperatures up to 900 0. without any deleterious effect and without being inferior to 4 the natural mica as regards insulatin power, hardness and cleavage. Such insulating bodies are especially qualified for use with electric cooking vessels, flat irons and similar apparatus, where they have to withway Applieation'filed May 31, 1913. Serial No. 770,945.

stand, as is well known, temperatures up to 400 C. and more, for I some considerable tune and not only temporarily.

In addition to the Well known steps to combine the initially loose mica particles by means of a binding" agent under an elevated temperature and high pressure. my new process oifers the distinctive feature, that,

the mixture of mica Waste or the like and blndlng agent is heated from 500 to 950 C. and that a binding agent is used consisting of aninorganic compound and having a meltlng point from 500 to 950 0. Such compounds are for instance employed as customary in the manufacture of micanite,

after which they are submitted simultaneously to great pressure and to a high temperature. Any suitable pressure may be em ployed, and the temperature will be just sufficiently high to melt completely the binding or fiuxing material without deleteriously affecting its qualities orthose of the mica. In another method of working, a layer of thin mica is covered with the binding or fiuxing material and then mica dust, which is a very cheap substance, is strewed over the surface. a When the desired thickness has been built up a covering sheet of split mica is laid over the top and the whole is pressed apd heated as above mentioned. A number of successive layers made in this may be used to form a plate or block of any desired thickness. a

I claim:

1. An insulating material of the character described, consisting of mica flakes pasted stroyed when heated to this temperature substantially as and for the purpose set forth.

2. An insulating material of the character described consisting of mica flakes pasted together under high pressure by a fiuxing material containing boron, silicon,

pressure, substantially as andfor the purpose set forth.

4:. The process of making an insulating material of the clfaracter described, which consists in mixing mica flakes with 'a fluxing material containing boron, silicon and lead and having a melting point between 500 and 950 C, heating the mass to said temperatures, and subjecting it at the same time to high pressure, substantially as and for the purpose set forth.

In testimbny whereof I aiiix my signature in presence of two witnesses;

FRIEDRICH BULLING.

Witnesses JEAN GRUND, CARL GRUND.