US 1879128 A
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Sept. 27, 1932. w DESPER 1,879,128
CIGARETTE Filed Oct. 16, 1929 Patented Sept. 27,- 1932 PATENT OFFICE ERNEST W. DESPER, OF WORCESTER, MASSACHUSETTS CIGARETTE Application filed October 16,
This invention relates to certain improvements in cigarettes, and more particularly to means employed in connection with the Wrappers therefor which are designed to prevent, or minimize the danger of setting fire to inflammable substances with which the cigarette may come in contact when discarded while lighted.
While various attempts have been made to produce a cigarette which, if discarded while lighted, will be unlikely to cause fires, these attempts, if even partly successful in this particular, have, so far as I am aware, been unsuccessful in retaining the usual qualities desired, the cost of manufacture usually being increased to a prohibitive extent, or features being introduced which are objectionable to the smoker, as by the introduction of any substance which impairs the flavor, or which would in any way be liable to be injurious to the person. Also, while cigarettes have been produced having wrappers which do not burn, or only burn under the forced draft when, being smoked, or burn so slowly that the filler is almost immediately extinguished when smoking is discontinued, they are undesirable, as smokers usually wish to be able to discontinue smoking temporarily, without being obliged to relight when it is desired to resume smoking.
The objects of my invention are to provide a method of treating cigarette wrappers, or the paper from which the wrappers are made, which will prevent, or tend to prevent the lighted cigarette, when discarded, from igniting inflammable substances with which it may come in contact, and to produce this result without causing the filler to be almost immediately extinguished when smoking is discontinued, and without affecting the flavor, or being injurious to the smoker, or causing discoloration of the wrapper, or substantially afi'ecting its combustability, or substantially increasing the cost of manufacture.
I accomplish these objects primarily by impregnating the paper wrapper, or the paper from which the wrappers are made, with certain substances which prevent the ash of the paper wrapper from readily disintegrating and which form therewith a vent the filler from bein 1929. Serial No. 999,934.
somewhat porous, or, infusible insulating wall about the burning filler, so that the heat therefrom is sufliciently confined to prevent inflammable substances, with which the cigarette may come in contact, while burning, from becomin ignited, but which, at the same tune, wilI permit air to be supplied to the burning filler to a sufficient extent to prealmost immediately extinguished when smoking is discontinued. Also, by lncorporating in the pores of the paper wrapper of the cigarette certain substances which, when burned, form certain compounds, the formation of which is attended by the absorption of heat, so that the wrapper is of an endothermic nature, (rather than exothermic, and is the case of the ordinary wrapper) the burning of which absorbs suflic1ent heat from the burning filler to reduce substantially the liability of damage being caused to materials with which the burning cigarette may come in contact.
For a more complete disclosure of the invention and the manner in which it is performed, reference is made to the following specificatlon, in connection with the accompanymg drawing, in which a sectional view of a partly consumed cigarette, embodying the invention, is illustrated.
In outward appearance the cigarette is the same as any ordinary cigarette, comprising the usual tubular paper wrapper a and tobacco filler 6.
According to my invention the wrapper, or the paper from which the wrapper is to 35 be made, is treated with an aqueous solution containing a borate, a phosphate, a tungstate and a sulphate, all of the group of alkali elements. This may be done in several ways, preferably by atomizing the solution onto the 90 paper of which the wrappers are to be made or by passing the paper web thru the solution, and then drying it, so that a residue of the above substances will be deposited in the pores and on the surfaces of the paper. 95 These substances do not, so far as I am aware, unite chemically, so that the paper is impregnated with a mixture thereof.
I have ascertained that the different papers which are used for wrappers require differone-half of this amount cut treatment in many instances, i. e. some papers, to secure reasonably satisfactory results, must be much more heavily impregnated with the mixture than others, so that tests must usually be made of the particular paper which is to be used in any instance, to determine the proportions of the different ingredients which will be the most effective for the purpose, the proportion of the mixture of the substances in the solution being varied approximately from 2 to 5 percent.
While various specific substances may be employed which come within the general terms aboveindicated, the particular substances which I prefer to employ in most instances, and with which the most satisfac tory results are secured are boric acid, ammonium phosphate, sodium tungstate and ammonium sulphate, and while the relative proportions of these substances will be varied according to the character of the paper treated, as well as the proportion thereof to the water in which they are dissolved, I have found it desirable to employ a percentage of the phosphate approximately equal to the total percentage of the other three substances, also to employ of the latter approximately of the tungstate. A formula which is satisfactory for many conditions is as follows:
Per cent H O 95.00 (NH HPO 2. 5 (NHQ SO 625 H BO 625 Na WO 1. 25
From experiment, however, I have ascertained the practical limits of the proportlons of the different substances contained in the solution which may be succesfully employed to be approximately as follows:
Per cent (NH,) SO .tto 2.08 NH, ,HP0, 1. Oto 52 B0 4: to 2. O8
Na WO 2 to 1. 04
the temperature due to the forced draft is b maintained the boron oxide will be melted and forma thin, flux like, glassy, tenacious mass, of low specific gracity, and, on cooling slightly, will tend to form a film about the filler,-or filler ash, and has cementing quallties, so that it acts to retain the other substances which are deposited by the coInbus tion. At the same time, the ammonium phosphate becomes decomposed into meta phosphoric acid and ammonia, the latter escaping,
while the former becomes, or would become 1 of the wrapper and provide a heat insulating enclosure for the burning filler which, if unbroken would be practically impervious to the passage of air, under which condition the'cigarette would be likely to be extinguished too quickly, when smoking was temporarily discontinued.
For the purpose of making this wall or film, slightly porous, or of breaking it up slightly, so that sufficient air may pass therethru to maintain combustion of the filler for a suflicient time to meet ordinary requirements, the tungstate and sulphate are employed, in the mixture, which are believed to have the following action when heated.
The sulphate is decomposed by the heat and causes the formation of sulphuric acid. The tungstate also becomes decomposed and the sulphuric acid unites therewith and forms 'tungstic acid, a yellow powder, which oxidizes at the temperatureat which fusion takes place and forms a mixture of diand tritungstic oxide, which is deposited in small, infusible particles, of relativelyhigh specific gravity, throughout the film formed by the borate and phosphate, and cuts thru the film and forms small perforations therein. When the film cools the oxide will be retained thereby, the substances forming the film acting as a cement and providing an enclosure for the burningfiller. The enclosure which is thus formed will be slightly reticulated, or provided with minute passages through which air may pass to the burning filler in suflicient quantity to support a slow combustion thereof for a time after (liscontinuance' of the forced draft caused by smoking, so that the cigarette will not be immediately discontinued, but may be laid aside temporarily without the necessity of relighting when it is desired to resume smoking.
The somewhat porous,' cylindrical wall which is thus formed about the burning filler y the combustion of the wrapper and fusion or heating of the substances with which it is extinguished when smoking is' impregnated, or coated, acts as a shield, or heat insulating enclosure, which prevents or tends to prevent the ignited filler, or particles thereof from coming into direct contact with inflammable substances, or. from communicating sufficient heat to such substances as to cause the same to be ignited. The substances with which the filler is impregnated tend to retard combustion of the wrapper, and the formation of the compounds resulting from the combustion of these substances is attended with the absorption of heat, that is, an endothermic reaction takes place when the substances with which the wrapper is impregnated are decomposed and certain products are formed as herein before indicated, so that the heat resulting from the combustion of the filler is partly absorbed and thus is reduced to such an extent that the danger of having the filler ignite inflammable material with which the burning wrapper may come in contact is greatly reduced. While the substances with which the wrapper is impre ated tend, to some extent, to retard com ustion, yet the wrapper will burn back somewhat in advance of the filler under the forced draft of smoking and will burn back at least as fast as the filler burns when smoking is discontinued. As the combustion of the substances with which the wrapper is impregnated prevent ready disintegration of its ash, ordinarily the burning filler will be completely surrounded by the ash of the wrapper, and, as the latter has some stability, it tends to hold the ash of the filler so that it shatters much less readily than when the wrapper is of ordinary untreated paper, the ash of which has no stability and shatters as soon as burned, so
that in no way assists in supporting the ash of the filler.
As the filler and Wrap er are burned, the burning filler will thus ecome surrounded with an incombustible, slightly porous wall through which sufficient air will pass to support the combustion of the filler, so that the filler will not become extinguished when smoking is temporarily discontinued.
In the drawing the conditions produced are illustrated, the slightly porous insulating wall 0 formed by the combustion of the wrapper being indicated as enclosing the burning filler d and its ash e at its end.
lVhile the proportions of the different ingredients should be varied according to the character of the paper which is employed as a filler, the limits of said proportions above indicated having been ascertained from results secured in testing the wrappers of various well known cigarettes, now on the market, it may be desirable, in some instances,
to increase the maximum proportions indicated, although it is not believed that, if the proportions are substantially reduced below the minimum indicated, reasonably satisfactory results would be secured.
The substance with which the wrappers are impregnated are nonoisonous and do not affect the flavor of the ller when burned and the cost of impregnating the paper, when performed on a large scale, is practically inconsiderable.
While, from the result of many experiments, I believe that the four substances with wh ch the wrapper is impregnated, as above mdlcated, are essential to the production of wrapper which, when consumed, will result in an endothermic reaction, and will prevent dlsmtegration of the ash and cause the formation of an infusible, slightly porous wall about the burning filler, I consider it possible that equivalent substances may be employed, WhlCh will enable similar results to be secured, and which will be within the spirit and scope of my invention.
. I clalm:
1. A cigarette having a paper wrapper impregnated with a mixture of substances comprislng a tungstate and a sulphate, which become decomposed when the wrapper is burned and form tungstic oxide, and a borate and a phosphate which form a ce inent for holding the particles of the oxide in the form of a heat insulating enclosure for the burning filler.
2. A cigarette having a paper wrapper impregnated with a mixture of substances comprising boric acid, ammonium phosphate, ammonium sulphate, and sodium tungstate.
3 A cigarette having a paper wrapper which has been treated with a solution contaming a tungstate, a sulphate, and a phosphate, all of the alkaline group of elements ang. aAborate. h
cigarette aving a a er wra er which has been treated with solution d dntaming ammonium phosphate, ammonium sulphate and sodium tungstate, and boric aci 5. The process of preparing paper for use for clgarette wrappers which consists in treating the paper with an aqueous solut1on containing a tungstate, a sulphate, a borate and a phosphate and then drying the paper.
6. The process of preparing paper for use for cigarette wrappers which consists in treating the paper with an aqueous solution containing a a1 aline tungstate, an alkaline sulphate, an alkaline phosphate, and a borate and then drying the paper.
7. The process of preparing paper for use i for cigarette Wrappers which consists in treating the paper with an aqueous solution containing boric acid, ammonium phosphate, ammonium sulphate and sodium tungstate and then drying the paper.
8. The process of preparing paper for use ERNEST W. DESPER.