[PT032ABV1], Technical Note, Thomas Alva Edison, April 8th, 1889


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[PT032ABV1], Technical Note, Thomas Alva Edison, April 8th, 1889

Editor's Notes

[MISDATED - TAE DATED THIS APRIL 8, APRIL 10 IS WHEN IT WAS RECEIVED BY SEELY; CHANGED DATABASE-PI] [Pat. 438,309 Insulating Electrical Conductors; Red Apl 10, 1889 H. W. Seely] The object of this invention is to obtain a tough flexible non inflammeable material for insulating electric wires##The invention consists in displacing the Hydrogen by a Halogen preferably Chlorine. To substitution of the Halogen being carried to just that extent necessary to make the resultant material non inflammeable The best substances are the Gums of the gutta family Gum Balata on account of its cheapness Is the gum which I prefer as a base for Chlorination##The method I use is the solution of the gum in Chloroform & passing Chlorine through the solution until properly Chlorinized-- This is ascertained by making films on glass from time to time & igniting them which test serves not only to determine the flexibility of the material but its inflammebility--##Too highly chlorinated residues are not so tough as when the material is not so fully chlorinated. The Reaction may be stopped at certain points or it may be carried so far that the film is somewhat brittle & then the solution may be mixed with Chloroform containing Balata not chlorinated but the addition of unchlorinated Balata should not be so great as to cause inflammebility##The liquid can be concentrated by evaporation or distillation to a thick syrup and the wires covered with cotton or other insulating material are passed through the solution & thence through Heated dring tubes the Chloroform an evaporation leaves a film tus rendering the wire not only waterproof but non inflammeable The cotton is preferalbly made non inflammeable by the ordinary processes now used for rendering fabrics non inflameable The liquied may be evaporated to a putty like consistency & put on the wire by a die & press in the usual manner##Claim-- The formation for insulating or other purposes of flexible non inflammeable material by the action of a Halogen on Gum Balata or analogous gums having similar properties##2nd Disolving the gum in a solvent not effected by the Halogen & then actiing on it by the Halogen##3rd The use of Chlorinated gum Balata for insulating purposes



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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
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