US1399026A - Fireproof varnish - Google Patents

Description

GR 195999026. i

UNITED STATES PATENT OFFICE.

CECIL L. SAUNDERS, GEORGE C. STANLEY, AND CHARLES W. BENNETT, OF ITHAOA, NEW YORK.

FIREPBOOF VARNISH.

Specification of Letters Patent.

Patented Dec. 6, 1921.

N0 Drawing. Original application filed October 13, 1919, Serial No. 330,384. Divided and this application filed November 3, 1920. Serial No. 421,525.

To all whom it may concern:

Be it known that we, CEoIL L. SAUNDERS, GEORGE G. STANLEY, and CHARLEs W. BEN- NETT, all citizens of the United States, each residing at Ithaca in the county of Tompkins and State of New York, have invented certain new and useful Improvements in Fireproof Varnish; and we do hereby cleclare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a composition of matter in the form of an emulsified varnish which is applicable to the fire proofing of fabrics in general, and especially the fire proofing of aeroplane wings. I

The object of the invention is to provide a composition or emulsified varnish which is less costly, and more efficient in use than those heretofore proposed.

With this and other objects in view the invention consists in the novel composition of matter, or emulsified varnish, all as will be more fully hereinafter disclosed and particularly pointed out in the claims.

This application is a division of our copending application Serial No. 330,384, filed October 13, 1919, and entitled Composition of matter and process of producing the same.

In order that the precise invention may be the more clearly understood, it is said 5-- It is well known that the fabrics from which aeroplane wings are produced are often subjected to fire risks, and that it is very desirable indeed to so fire proof said fabrics without destroying their strength that should they become ignited, the flame will not spread and the aviator may thereupon reach a landing in safety. It is also well known that it is very desirable to coat fabrics in general with a fire proofing material, having the above mentioned characteristics, but to all of the materials and methods with which we are acquainted, various objections exist.

That is to say, prior processes either rot the fabrics, or the flames will spread unduly, or it is so expensive to apply the coating that they have not proved satisfactory in service. Especially has it been found in the prior processes that the fire proofing coating, whatever it may be, is easily Washed out, so that after the fabric has been subected toserious wettings, its fire proofing qualities are greatly deteriorated.

Further, it has been found in practice that it is a very diflicult matter indeed to so open up the fibers of the material that the fire proofing substances will thoroughly penetrate the same.

In the invention, now to be described, all the above objections are done away with, as will presently appear. That is to say, as stated in our said copending application, above mentioned, we have discovered that although hydrofluoric acid will readily destroy the fibers of fabrics in general, yet, if a fabric such as cotton is first boiled in water, to remove the size, and then treated with a Weak solution of hydrofluoric acid, say about two parts in one hundred parts of water, as by dipping the said fabric for thirty minutes in the solution, and if it is then washed, and brought to a semi-dry state, the fabric will be found not to be 3 weakened at all, but even strengthened to a {I degree. 5' 0 Its pores will also be found to be so open that it will readily take the fire proofing solution, about to be described.

After the above mentioned treatment with hydrofluoric acid, we next may pass the fabric through a solution of sodium stannate, preferably having a specific gravity of 1.075. The fabric is subjected to this last mentioned solution for about say one half minute, or somewhat longer, whereupon it is wrung out and dried. We then pass the said fabric through a solution of ammonium sulfate, preferably having a specific gravity of about 1.045 and it is subjected to this last mentioned solution for about the same time as just stated, or about say one minute or a little longer.

The fabric is now taken out of this am; e solution whereupon itmay be wrung out and dried, or it may be washed with water and dried. The fibers of the fabrio, if closely examined will be found to be coaged with hydrated oxid of tin or stannic aci The reaction may be stated as follows This said hydrated oxid of tin SnO a'I-I O ages is in an exceedingly finely sub-divided condition, and it functions as a most efficient fire proofing material or agent for preventing the spreading of flame, Whether it be applied to fabrics, to the fibers before the fabrics are made up, or even to Wood. Whereas, the above treatment is found to be efiicient in practice, our preferred process consists in the following We take a mixture of sodium stannate and of ammonium sulfate, as above mentioned, but preferably in the solid condition, and grind them together until the fumes of ammonia come off, whereupon we add to the mixture any suitable varnish. This old or well known. varnish may be of a gummy or resinous nature, or it may be the well known varnish that is now used on aeroplane wings, which is a cellulose nitrate, or a cellulose acetate. After the ordinary varnish is thus mixed with the above reagents, the grinding is continued until we have produced a thorough and intimate mixture of the said ordinary varnish, and the hydrated tin oxid that is produced by the reaction during the grinding operation.

As this reaction cannot, under the circumstances be a complete reaction, the ordinary varnish will be thus emulsified, or intimately mixed, not only with the hydrated tin oxid, above mentioned, but there will also be present some ammonium sulfate, as well as some sodium stannate, and undoubtedly some sodium sulfate too, each of which ingredients are good fire proofing reagents. The presence of the ammonium ion undoubtedly has a good effect in causing a thorough incorporation of the hydrated tin oxid into the fibers of the fabric when'th-e varnish con-- taining said ingredients is applied thereto.

Especially will this incorporation be very thorough if the fabric has been previously treated with the hydrofluoric acid solution above mentioned.

The varnish, whether it be a resinous one or one having a cellulose base, after being thus emusified, so to speak, with the fire proofing substances, above mentioned, constitutes an article'of commerce in itself, and We wish it to be distinctly understood that this invention comprising said emulsified varnish relates broadly to such a composition no matter to what substances it may be applied. Further, although this said emulsified varnish may be made by other processes, than that mentioned, yet, we prefer to produce the emulsified varnish in the manner above disclosed because it is an efficient way to impart into ordinary varnish a number of fire proofing agents Which serve, together with the former treatment of the fibers, to so thoroughly impregnate the latter that in practice, the product is found to resist fire to a degree much higher than those produced by other methods with which we are acquainted.

It is obvious that those skilled in the art may vary the composition of the product without departing from the spirit of the invention, and therefore, we do not Wish to be limited to the above disclosure except as may be required by the claims.

WVhat We claim is 1. A fireproof coating composition comprising varnish having intimately incorporated therein a hydrated oxid of tin, substantially as described.

2. A fireproof coating composition comprising varnish having intimately incorporated therein a hydrated oxid of tin and sodium stannate, substantially as described.

3. A fireproof coating composition comprising varnish containing in an emulsified form substantial percentages of a hydrated oxid of tin, sodium stannate, and ammonium sulfate, substantially as described.

In testimony whereof we affix our signatures.

CECIL L. SAUNDERS. GEORGE C. STANLEY. CHARLES W. BENNETT.