US2606107A - Incendiary gels - Google Patents

Description

Aug. 5, 1952 L F FIESER 2,606,107

INCE'NDIARY GELS Filed Nov. l, 1945 Syvum/Wo@ L ouls F- Fiese!" Patented Aug. 5, 1952 INCENDTARY cELs Louis F. Fieser, Belmont, Mass., assignor to the United States of America as represented by the Secretary of War Application November 1, 1943, ,Serial No. 508,632

15 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates generally t0 gelled fuels and improved gelling agents or thickeners therefor. More particularly, the invention is concerned with the production of new and improved gelled hydrocarbon fuels and gelling agents therefor, for use in incendiary munitions of both the burster and the tail-ejection types, in flame throwers, in hand grenades, in re starters and, generally, in any incendiary munition which utilizes a combustible liquid or low-melting solid or gelled fuel.

Prior to the present war, rubber was used to thicken or gel gasoline and similar hydrocarbon liquids to make gelled incendiary fillings. However, because of the scarcity of rubber, it has been necessary to resort to and develop other types of gelling agents. This has been a rather diiicult problem since the requirements of such incendiary fillings are manifold and exacting. The incendiary gels must be stable and free from syneresis throughout a temperature range from 40 F. to 125 F., since incendiary munitions must be capable of use from the cold regions of Alaska to the tropics. The incendiary gels must have a high inner cohesion so that when they strike a target, they will adhere thereto without falling off so as to do the greatest damage.

It is known that soaps of polyvalent metals, particularly aluminum, are capable of producing gels with both aliphatic and aromatic hydrocarbons. for this purpose are of two main types. One type comprises the group of the aluminum soaps of saturated fatty acids (usually but not necessarily of vegetable origin) as exemplified by the aluminum laurates, palmitates, stearates and myristates. Aluminum stearate has certain disadvantages as a gelli'ng agent for incendiary fuels, both because a heat treatment is required for incorporation into the fuel and because 'the gels are hard and friable and lack the cohesive and adhesive character desired in an incendiary fuel. Soaps of fatty acids of lower molecular Weight, for example, `aluminum laurate vand my- The aluminum soaps which may be used ristate, may solvate fairly rapidly at ordinary temperatures but give gels which lack body, which tend to undergo syneresis at low temperatures, and which are of generally inferior quality.

The ysecond type of aluminum soap, as classied with respect to performance in the gelling of hydrocarbons, is exempliiied by the aluminum naphthenates and aluminum oleates, these differing from the soaps of the *first type in that they are either resinous gums or low-melting solids. As thickening agents for hydrocarbon solvents, the soaps of the second type have the 2 disadvantage that gelation of the fuel is not easily accomplished without either a heat treatment of the mixture or a special processing of the soap. Thus, although a resinous aluminum naphthenate can be processed by alcohol washing to give a product which will solvate at ordinary temperature, the process is costly and the yield is poor. Another method of processing a naphthenate to secure low-temperature gelation is by precipitation as the solid hydroxyaluminum soap. However, the melting point of the resulting product is so low that it may be difficult to avoid agglomeration of the material. As regards aluminum oleates, no prior methods appear to be available for effecting gelation in a simple manner without heating. Furthermore, the aluminum naphthenate and oleate soaps tend to be rather weak, and an excessive amount of soap is required to produce a gel of desired viscosity.

It is evident from the foregoing that aluminum soaps of both the paraffin carboxylate type and the naphthenate-oleate type are subject to certain serious disadvantages and limitations as thickening agents for the production of incendiary gels.

Accordingly, the primary object of this invention, generally stated, is the provision of new and improved gelling agents for producing highgrade incendiary gels or fuels which meet or eX- ceed existing specification and requirements.

A more particular object of this invention is the provision of a new and improved incendiary fuel in the form of a cohesive, elastic, highlystringy gel that is capable of adhering as a thick mass to walls, ceilings, and even smooth glass surfaces, and which when ignited burns for a relatively long period of time without melting or running, producing a vigorous, highly destructive flame of great incendiary action.

A further object of the invention is the provision of a gelled fuel of the foregoing type further characterized by having the following combination of properties:

(1) Low-temperature coeicient whereby desirable properties are retained over a wide temperature range.

(2) Thermal stability and freedom from syneresis when stored either under tropical conditions or under frigid conditions, or when subjected to cyclic heating and cooling conditions.

(3) Shock stability and freedom from syneresis when subjected to the action of burster charges of the type likely to be employed in incendiary munitions.

Another object of the invention is the provision of a new and improved low-temperature gelling or thickening agent capable of converting any suitable liquid hydrocarbon fuel, such as gasoline (leaded or unleaded), benzene, naphtha, petroleum ether, Stoddards solvent and diesel oil,

vision of a W-temperature gelling or thickeningY agent, and a process of utilizing the same, which permits the lling of incendiary munitionsl with gelled fuels under adverse field` conditions-such;

as are likely to be encountered-:in thetheatre of operations.

Other objects of the invention Will,.in.part,.be.

obvious, and Will in part appear hereinafter.

For a more complete understanding of the nature and scope of the ilnvention, reference may be. had to the following detailed description thereof', setting forthv by way of illustration certain specific compositions. and methods of4 prepparation. and. utilization, .taken in. connection with. .accompanying drawing in. which. the single figure isy aperspective view of a standard-'wooden structure used in testing. the. incendiary characteristics of different incendiary. gels forming embodiments of thisinvention. In. accordance with the. present. invention, it has been found. thatthe foregoing objects thereof may be attained by employinga new andimprov'ed' composite gelling or thickening agent comprising two or. more components suitably combined and incorporated with a hydrocarbon liquid, all as more particularly described. and claimed hereinafter.

Broadly speaking, the composite thickener. of the present invention comprises two. or more. components. which may bedesignatedand referred to as' component A and component B. Component A may. comprise an aluminum soap of asoapformingjsaturated fatty acid of not more than` l5 carbonatoms., and preferably one having from 8 to 14 carbon atoms. Component B- may be said to consist generally of (1)- a soap-forming carboxylicacid having one or more'carbocyclic rings; orV (2) a soap-foamingA unsaturated fatty acid;` or (3) theY corresponding aluminum. salts of' such acids; or (4) any mixtures thereof.

Composite thickeners. of the above type have been found to be capable of effecting low-temperature'gelation of hydrocarbon liquids. generally, producing gelled fuels having' .the required properties as outlined above.

In preparing the gelled fuels of the present invention, the preferred thickener may be incorporated in, any convenient manner with the selected liquid hydrocarbon and the mixture permitted to stand until gelation occurs. However, in some instances-it may be preferable to form a solution of' one component of the improved gelling agent (for example, component A), in the fuel to be gelled and thereafter to add. the other component orA components (for example, component B) to the mixture. In still other instances, it may be desirable to mix the composite gelling agent at' an elevated temperature with a 'portion of the fuel to be gelled and then to blend the resulting homogeneouszgummy product with further' quantities ofthe same or different liquid hydrocarbon fuel.

Another desirable method of producing the ultimate gelled fuel is to incorporate. the composite gelling agent with a sorbent material (preferably combustible) havinga relatively fine' state of subdivision, using a sufiicient amount of the sorbent material to. produce a granular composition which may thenbe mixed with the hydrocarbon liquid' to be" gelled. The use of acombustible 4 sorbent material such as charcoal, flour and the like is particularly advantageous, not only because of the desirable physical properties of the resulting granular material, f but also because, unexpectedly, the final gel is characterized by a definitely enhanced incendiary action.

As indicated above component B may consist either of the aluminum soaps of the stated soapform-ing acids, or the free acids themselves. In

- certain instances'it may prove advantageous to employ analumi-num soap for component A and two aluminum soaps, or one aluminum soap and one free acid, or two free acids as component B; Thus for example, the gelling agent may consist of the aluminum soaps of coconut fatty acids (which. are characterized by a high lauric acid content) as component A, together with aluminum naphthenate and aluminum oleate, as` component B. In short, it will be evident that components-A vand B. do not necessarily consist of pure individual chemical. compounds. Onthe contrary, for economic and other reasons, it. is usually preferable to employ mixtures of compounds as-the individual components which are rich in the desired ingredients. In this. connection it may be mentioned that various acids and soaps, in. addition to those identified above, may be present either as adventitious materials included in the components or as deliberately added adjuncts.

As indicated above in. characterizing component. A, not all soap-forming fatty acids are suitabley for producing the improved gelling agent ofthe present invention. Indeed, selection must be made from the limited. group comprising the aluminumsoaps of. saturated carboxylicacids. of not. more than 15 carbon atoms4 and preferably from those having from 8 to 14 atoms inclusive. Lau-ricv acid is. a preferred ingredient because of its. availability, but this. may be replacedv by the higher homologue, myristic acid, or by the lower homologues,v capric or caprylie acid, or by synthetic saturated acids, for example, Z-ethyl-nhexoic. acid. The common acids having more than l5 carbon atoms, e. g., palmitic and stearic acid,y are definitely unsatisfactory, although, as will be shown, substantial amounts of these and other acids` outside the Cri-C14 range can be tolerated along withcomponents A and B with-k out detracting materially from the quality of the thickener.

There is no restriction with regard to component B, and either the free acids, the aluminum salts or mixtures of either or both may be used. Thus component Bv may be an aluminum naphthenate, an aluminum oleate, or the aluminum soap of a vegetable or animal ,oil acid rich in oleic acid but containing as well acids of both higher and lower degrees of unsaturation. If desired, one may employ the aluminum soaps of natural or synthetic acids' simulating the properties of either oleic acid or naphthenic acids, for example, acid' mixtures obtained by the partial oxidation of petroleum fractions.

Furthermore, the invention is not restricted to the use of single compound for component B, for mixtures of two or more soaps or two or more free acids or an acid and a soap selected from the group may be employed. Nor is there any restriction inthe manner in which a selected component is made.. for the soaps, for example, may. be. produced by any of the known methods, including precipitation from. an aqueous solution l `para-aluminum oleate of the sodium soap or by fusion of the acid with anV oxide or hydroxide of aluminum. t

l'.lypical formulations for the preparationof thickeners; are as follows:

- h. (1) 1 partaluminum soaplof coconut acids 1 part-al-uminum naphthenateV (2) 1 part-aluminum soap of vcoconut acids 1 partaluminum oleate (3) Y I h 2 partsaluminum soap of coconut acidsv 1 partaluminum naphthenate 1 part-aluminum oleate r`(4) n '2 parts-aluminum soap of babassu oil acids 1 part-aluminum naphthenatev 1` parue-aluminum oleate 5) 2` :parts-aluminum laurate 1 part-aluminum naphthenate i" Several additional satisfactory ormulationsare indicated'fin the'specic: examples given below,

andjit will be evident that 'considerablevariation is possible with 'respect to ingredients. missible with respect to the proportions of the ingredients, and the proportions indicated in the examples are typical. While the mean proportions of the ingredients of the thickener are in the neighborhood of equal portions of components A and B, there is a fair amount of latitude pos.- sible in the range of percentages of both ingredients which yield .satisfactory thi'ckeners and which are within the scopeof this invention. `In general, a satisfactory thickener will result from a composition having fromv 1 to 2.5 parts of component A mixed with from 1 to 1.725 parts of com ponent B; this will be clearly shown in the yillustrative examples which lfollow. v Within Athis framework, ranges more limited in scope are best suited for specific ingredients ofl component A. For example, when component A is the aluminum soap of the fatty acids found inA coconut oil, the preferred proportions thereof are from 1 to 1.7 parta fI-oweverwhen component A is the aluminum soap of'a saturatedfatty acid fraction having from 8 to 14 carbon atoms per acid molecule, the preferred proportions'thereof are from 1.5 to 2.5 parts, except when it is combined with the the selection of the aluminum salt of naphthenic acidas component B. In compositions having the al'uminumfsalt oi naphthenic acid as component B the 'preferred range of component A is from 1 to 1.7 parts regardless of the ingredients thereof. These preferred embodiments are not to be construed as limiting the range of proportions in so far as the scope of the invention is concerned.

The-compounding of the thickeners caribe done byvarious processes, some known to the prior art and some new. One new process which I have devised consists in incorporating solid aluminum coconut soap and viscous aluminum naphthenate with kerosene or other high-boiling fuel in a heated mixer. Another is to grind aluminum naphthenate with a sorbent combustible, such as dry wood ilour, and mill dry aluminum coconut soap into the mixture; this 'has the advantage cf giving a solid thickening agent very easily dis#- persed inahydrocarbcn fuel. The preparation 'of vthefmaterial in the form of a dry Solid also Within limits, variation is also per- 8.4. parts-motor gasoline Vcan be4 accomplished by methods already known for the precipitation of water-insoluble metal salts from aqueousfsolutions of the sodium soaps; for example by the process described by A. Minichfn British Patent 507,361 (June 14, 1939), or by the process of C. C. Towne (U. S. Patent 2,205,994, 4June 25, 1940). Thus a convenientprocedure consists in preparing an aqueous solution of the sodium salts of the combined acid components containing free alkali, and to add an aqueous solution of aluminum sulfate; this precipitates the thickener asa magma which can be collected byfiltration and dried to a granular solid.

In -still another process, described below in detail, the mixed aluminum soap thickener is produced in the presence of the fuel which is to be gelled. For example, powdered aluminum coconut: soap, with or without admixture with a sorbent combustible such as wood-flour or lampblack filler to increase the incendiary ecacy of the gel, is made into a thin slurry with motor gasoline and a concentrated solution of aluminum naphthenate in gasoline is added and the whole briefly mixed. A uniform gel is set up after standing for a few hours. v As-an example of. a within'thehscopeof the present invention, we maycitethe preparation of hydrocarbon gels by mixingY with the hydrocarbon fuel an aluminum vsoap selected from the group represented by component A -together with a free soap-forming unsaturated fatty acid or cycloparafnic acid. vTypical formulations are as follows:

' (6) y 7 partsaluminum soap of coconut acids 4 partsArmours Neo-Fat 3R` (49% oleicand linoleic acids) l 87 partsmotor gasoline 2 parts-lampblack v A(7)l 9 harter-aluminum soap of coconut acids 5 partsT-Neo-Fat 3R 2 inarts-lampblack These gels are made very easily by briey stirring the aluminum soap and the ller with gasoline to form a thin slurry and addingthe unsaturated acidv component. After brief mixing, no

further processing is required and a stiff transient gel isset up within a. few minutes at ordinary temperature and changes to a stringy permanent gum after about one day. Formulation (6) is well adapted to use in tail ejection bombs,V `while formulation (7) is distinctly tougher and is recommended for a burster-type bomb where resistance tothe shattering action of an explosive is required.

The gels prepared in gasoline (for example, ordinary motor gasoline or gasoline of .11.5lbs. Reid vapor pressure and F. aniline point) at concentrations of 12 to 13.5% vof thickener are very full-bodied and strong and verywell adapted to use vin explosive type bombs because of their strength and resistance to the shattering action of theburstercharge. Gasoline gels containing 8-9% of thickener have considerable body and possess desirable stringiness and extensibility and are well suited for use in bombs of the tail-ej ection type or in incendiary hand grenades. Gels in higher boilingjuels,.exemplified by kerosene and Stoddard solvent, containing approximately 8% of thickener, constitute particularly effective fillings `for handincendiary units consisting of a combustible container of the plasticized nitrocel# lulose type, and a thickened oil filling. In een.-

further variation Vcomi-ng 7 eral, a good effective incendiary gel will result from a mixture consisting from 84 to 92 per cent by weight of gasoline or other light liquid hydrocarbon fuels and from about 8 to 16 per cent by weight of any of the thickening composition disclosed. Y

We have characterized the gels obtained from our new soaps as to body orapparent viscosity to a limited extent bythe falling ball method, vand also by the use of a Stoermer viscosimeter equipped with a paddle, as described by lGeddes and Dawson in Ind. Eng. 34, 163 (1942), wherein the revolutions per minute are plottedl against the load imposed. The average weight required Ato produce a given rate of shear can be used as a characterization of the degree of body of the gel. A perhaps preferable method is with the use of the Gardner mobilometer, and here a brief indication of body can be given as the load required to pro/duce a fall of 10 cm. in 100 sec.

Another significant characterization is the time required for the dispersion of a thickener in a f given fuel to give a mixture from which the particles Will not settle on standing. The gelation time is also important, and this can be dened as the total time after mixing during which the gel can be easily poured, for example, through a 60 conical funnel with an outlet of 0.625 inch internal diameter and 1% inch long. The gel is described as pourable as long as 90% of a 500 g. sample will pass through the funnel in not more than secs. K

Another test which I have found useful because it gives a ready over-all index of the body and strength of the gel is designated as the drag test. The test is made in a '7-ounce screwcapped glass bottle (21% outer diameter) which is charged with enough gel to give a total weight of 325 g. A plunger, consisting of a 11/2" by 4%." strip of 0.03-inch Celluloid with a centered hole 1/8 from one end, is pushed to the bottom of the bottle and this is capped and allowedv to stand overnight at 77i2 C'. To make the test, the plunger is attached to a hook at such a height that the bottom of the bottle is 7 above the table top; the bottle is released and the time of fall determined. The plunger with adhering gum is then weighed.

-I -have also assessed the gels of the present invention with respect to their incendiary eciency by making burning tests conducted in a draft-free room on a standard structure using Wood of a -given grade and conditioned in the same Way to permit reliable comparisons. The standard structure used in these burning tests is shown in the single gure of the drawing.

It consists of a base A of dry whitewood, with posts B, B' and C, C of dry hemlock upstanding therefrom. Cross pieces E and D, also of dry hemlock, are screwed between the sets of posts B, B and C, C', respectively, as shown. The posts B, B and C', C are firmly nailed to base A with B-inch nails forced into previously drilled holes, while the cross pieces E and D are held in place between the posts by 21/2-inch, No. 11 flat-headed screws. The different pieces making up the structure have the dimensions shown in the draw- 111g.

The test is made by dispersing a standard sample of 97.3 cc. of incendiary gel from a calibrated grease gun on the base board A and noting` the time of burning and determining the amount of wood destroyed by weighing the pieces before and after the test, the charred wood being scraped clean before the final weighing.

EXAMPLE I Gel from:

5% aluminum coconut soap 5% aluminum naphthenate gasoline (Esso Extra) The naphthenate is added to the gasoline while this is being circulated through a homogenizer, such as a gear pump. When the naphthenate is dispersed, the coconut soap is added and the temperature is brought to 28 C. by frictionfrom the pump. A satisfactory gum is produced in 20 to 30 minutes and requires little subsequent aging to reach a permanent state. A i'lller can be added after the naphthenate has dissolved, thereby improving the incendiary eiciency, as shown in the following results of burning tests contained in Table I. An average value obtained with a rubber gel is included, and the comparison shows the superior performance of gels prepared with the present thickener. y

EXAlVIPLE 2 Gel from: 5% aluminum coconut soap 3% aluminum naphthenate (Nuodex) 0.5% lampblack 91.5%v gasoline (Esso Extra) The gel is prepared in the manner of the gel of Example I, and is full bodied and tough, and burningv tests gave the values 502 g. and 452 g.

Gel y from:

4% aluminum coconut soap 5% aluminum oleate (Shepherd) 90% gasoline (Esso Extra) 1% lampblack (cyanamid).

y EXAMPLE 4 Field filling of a bomb with a gel from:

21A gals. of a 16% solution of aluminum naph thenate in motor gasoline 2.1 pounds aluminum coconut soap 6.9 ounces lampblack 4% gals. motor gasoline The aluminum coconut soap and lampblack are stirred into the gasoline to give a fluid slurry 9, which is poured into the bomb through a funnel. Thevsolution of naphthenate is then added, the bomb is closed with a plug or a burster well, and the contents mixed by brief tumbling. The initial gelation results in afew minutes and a final gel is set p after storage at about 20 C. for 56 hours.

' EXAMPLE 5 Powdered thickener from:

2.36 lbs. aluminum naphthenate 1.88 lbs. dried wood flour 2.36 lbs. aluminum coconut soap f The powdered thickener is prepared by incor-l porating the' aluminum naphthenate into wood flour ina meat grinding machine, milling'the mix for 10-15 minutes in a Simpson mixer', adding aluminum coconut soap and milling a few minutes longer. A granular powder results which tends to agglomerate slightly on standing, but it can be loosened and poured readily through a iunnelinto a bomb charged with gasoline. Gelation takes place a few minutes after mixing the powder with gasoline; and if the loaded bomb is set on its side, a satisfactory gum can be obtained even-without tumbling. After 5-6 hours the gum reaches a terminal state and is readyfor use. A suitable filling for a bomb consists in 5.95 lbs.

of the above powder added to 4 gals. of gasoline .Y

in the bomb and followed by an additional 2 gals. of gasoline. Field trials indicate that the gel is tough and resistant to shattering.

The powder above described is an excellent thickener for the filling of frangible hand grenades. For example, the grenade can be stored and shipped without the fuel but charged with the` proper amount of the aluminum soap-wood flour powder; at any time prior to use, gasoline can be added and the grenade shaken briefly and allowed to stand for a few minutes for gelation.

The gel as described when submitted to the standard burning test, burns for the unusually long time of 61/2 minutes and destroys 645 g. Iof wood. The stability at both 40 F. and +155 F. is excellent.

EXAMPLE 6 -lb. charge of aluminum naphthenate 'is put into a steam-jacketed mixer heated with steam at a pressure of about 5 lbs. and milled until it becomes sticky and doughy (about 5 minutes). A previously prepared suspension of 5 lbs'. of aluminum coconut soap in 10 lbs. of diesel fuel, made by adding the powder slowly and paddling it to an even slurry, is poured slowly into the naphthenate in the mill at such a rate as to keep] the mix Adoughy and to avoidna localexcess vof unmilled uid. After vthe addition is complete, the cover is put in place and the mix is milled for 30 minutes, with careful control of the temperature (by occasionally stopping the n iill and inserting a thermometer) The gum should reach a temperature of 75-85 C. `in--1l5 minutes, and at the end of 30 minutes it should be at 95-100 C. Y

and not over 100- C'. The resulting thickener is a soft gum.

.For thepreparation of 19.2 lbs.- of` incendiary gum.- 5.l lbs. of the above thickener is put through a Hobart meat grinder, using -a delivery plate having 1/-inch holes. The issuing ,stream of soft, spaghetti-like strands is run directly into a 5-gal. tank containing 13.5 lbs. of gasoline which `is being vcirculated by means of a gear pump. After the addition' is complete, the mixture is kept circulating for' 15-20 minutes, when it becomes thick and fairly well mixed, and it is `boiling point of water.

then pumped directly into the bomb and allowed to stand for 5-6 hours for the setting up of the final gel. '-'l A standard sample of this gel, which 'shows excellent stability in the range-from 40 F.to +1i55 F., destroys 588 g. of wood. The gum is more resistant to the'shattering action of an explosive than any of those described in the above examples. It gives excellent performance in both 30lb. and 1 00 lb.burster'type bombsY and also performs well in Atail-ejection bornbs. VThe filling operation is simple and adaptableV to the plant' scale filling of incendiary bombs.

EXAMPLE '7 Thickener prepared from the coprecipitated aluminum soap from:

2 parts coconut fatty acids 1 part Vn aphthenic acid 1 p'ait oleic acid The coprecipitation is carried out by the process of British Patent 507,361, namely by addition of aluminum sulfate solution to a solution of the sodium soaps ofthe combined acids in the presence of excess alkali at temperatures below the The precipitated material is collected by filtration and dried in air or in vacuum at temperatures not exceeding 150 F. and with care to avoid any local overheating, due, for example, to the packing of the material in too thick layers. The moisture content of the final product is preferably kept below 2% as determined by the loss in weight on air-drying a sample for 15 hours at 150i5 F. This thickener is fully soluble in gasoline and kerosene and other hydrocarbon solvents and is easily incorporated into such fuels by brief mixing. The dispersion time and setting time in gasoline, for example, of Reid vapor pressure 11.5 lbs. and aniline point 140 F. is dependent on the size and porosity of the acid particles and can be controlled readily by controlling the character of the solid. Thus a typical sample ground to a rather fine powder showed the dispersion time of 1/4 minute and a setting time at which it became unpourable of 1K2 minute. When compressed by hand into 1/8 pellets, the respective times were 11 minutes and 60y minutes. As an illustration of the way in which the time for dispersionand setting canbe descreased, pellets, compressed in: the same waybut utilizing thickener powder mixed with 1% dried wood flour showed a dispersion o f 3 minutes and a setting time of 51/2 Vminutes. kThe same powder without wood flour when compressed on a roller at 5,000 lbs. per square inch and secreened to 8 mesh, showed a dispersion time of 9 minutes and a setting time of 13 minutes.

Gels' prepared in the gasoline specified above, using 50 g. of thickener to 36.6.4 g. of the gasoline, when tested with the Stoermer viscosirneter give values for the revolutions per minute as low ,V as 0.2 at a load of 600 g. When tested after a period of aging at F. for 20 hours, the RWP. M. at a load of 600 g. is not in excess of 3.0. Cooling of the gel at -40 F. .and inspection for syneresis on agitation or a tendency to turn brittle, reveals no such shortcomings.

Eight per cent gels of the thickener in the same gasoline, when tested in the Gardner mobilometer after the sample has stood in the tube for four hours at 77i2 F. are found to have apparent viscosities such that the load required'to produce a fall of 10l om. in 100 sec. is not less than 500 g. nor more than 1200 g.

1 1 kEXAMPLE s v,

Gelsl in gasoline or in lkerosene are prepared byV mixing the aluminum coconut soap with the fuel, adding the fatty vacid component, and agitating the mixture at ordinary temperaturefor a short time either by stirring o-r by passing through a gear pump homogenizer. An initial stiff gel il produced, usually'in less.V than .one hour, and change to a more stringy vconsistency after standing for about 24 hours.

Table II below lists formulations employing various acid components, including Armour and Company's Neo-Fat 3R (40% oleic, 60% linoleic), Neo-Fat 17 (C20 and .C22V unsaturated acids), Neo-Fat 19 (C20 acid with 3 and 4 double bonds); also oleic acid, the acids of linseed oil, and the cycloparamnic naphthenic acid. Examination of the data descriptive of the gels will show that the most satisfactory performance 12 terial and in the proportion of free fatty acid as in Example 8b, brings about an improvement in both respects and this gel is very satisfactory as a filling for a tail-ejection bomb. On the 5 other hand, it is not strong and tough enough to stand a black powder explosion or an excessive amount of high explosive charge. Where such qualities are desired, the preferred formulation among those presented is No. 8d. The improved 10 burningv characteristics resulting in the use of lampblack as a filler can be seen from Aa comparison of the burning tests for gels. 8b and 8c. The results indicate that oleic acid alone (gel 8h) is not as satisfactory as a mixture rich in thev doubly unsaturated linoleic acid. Linseed oil acid (gel 8k) gives a gel of satisfactory characteristics when freshly prepared but in general I would not recommend the use of a component so sensitive to oxidation because of difficulties which might arise as the result of aging. Naphthenic acid (gel 8i) is not a very favorable acid component alone, for the gels tend to lack body. However, the data vgiven for gel 87 indicate that mixtures of cycloparainic acids present deis obtained with lNeo-Fat 3R and Neo-Fat 19. 25 sirable possibilities.

TABLE IL GASOLINE GELS PREPARED WITH ALUMINUM C0- CONUT SOAP (ACS) AND VARIOUS ACLD COMPONENTS AND BINDERS Percent Acid Component No. ACS Binder Remarks 8a 5 2 Neo-Fat 3R Good at 40 C., slightly thin at 52 C.; burning test 336 g., 1 min. 46 scc. 8b 7 4% Neo-Fat 3R Stable on cycling at -40 and +52 C.; good body throughout this range; stringy; burning test: 402 g., Zi min. 8 7 [4% Neo-Fat 3R Improved incendiary efciency; burnc [2% Lampblack ing test: 531 g.

5% Neo Fat 3R Tolligh, durable gum, withstands ex- Sd 9 'ambltag phglxo'by black powder, stronger 0 e0' a Stronger than (c),slightly less resistant 8e` 7 tltlglgl: to explosive wave than (d).

8f 5 2% Neo-Fat 19 Gelled at 21; very similar to (a); burning test 399 g., 2 min. 30 sec.

,8g 5 2% Neo-Fat 17 Vy thick, but rather brittle and jelloe. 8h 5 2% Oleic Acid Less satisfactory at low and high tcmperatures. Y 8i 5 2% Naphthenic Acid.. Rather thin gel.

8j 5 {2% Naphthemc Acd: Full-bodied but rather jello-like. s'k y 7 }Good gel, particularly tough and stringy at 52 C= The amounts of the two components and the ratio between them is of` some significance and the formulation is best varied to meet a specic use. Thus the gel No. 8a has a tendency tobecome thin` at elevatedtemperatures and gives a somewhat low value in the wood burning test. An increase in the total amount of 'added ma- 55 described in Example 8. TABLE III. GASOLINE EXAMPLEQ Y oleic-ZirtoZeic acids in combination with various `aluminum soaps The gels listed in Table III are prepared as GELS PREPARED WITH NEO-FAT (N-F) 3R (40% oLEIC. 60% LINOLEIC) AND VARIOUS ALU. MINUM soAPs Aluminum Soap N No, Remarks g Component Acids f YQtr-... 4 r7 50 Laurie, 20 myristic 10 pal- Very thick and strngy; mitre, 5 stearic, 15 -F 3R. good stability vfrom to 52 C. 9b i 7 55 myr1stic, 20 palmitic, 10 Good at -40 C. but v ear'ic, 10 N-F 3R, 5 naphrather thin at 52 C.

eme. 9c 4 7 15 naphthenic, 45 myristic, 20 Strlngy, butY somewhat gralmiticy stearic, 15 N-,F thin. Y

9d 4 7 50 2-thylhexoic, 20 myristic, Very fu1l-bodied, fairly palmitic, 5 stearic, 15 N -F stringy. 9e 4 7 1o niyristic, 1o palmare, 5 vsughuy snort an 40 to l stearic, l5 N-F 3R. +25 C., thin at 52 C. 9j 4 7 Hydronaphthalenedcarboxy- Very thick, jello-like.

lic acids (Du Pont).v f

In this series, the acidl component (Neo-Fat 3R) was that found most generally appropriate in the example of Table II. The aluminum soap component is made bya process of precipitation or coprecipitation from an aqueous solution containing free alkali. utilizing the acids and acid mixtures indicated. Example 9a shows that a satisfactory gel can be obtained with a mixture of acids roughly approximating that ordinarily found in the acids of coconut oil. If'the lauric acid is omitted as in Example 9b, the heat stability of the gel is denitely less. vA considerable increase in the myristic acid to compensate for the absence of lauric acid leads to a gel of less satisfactory character (9e), for it does not possess adequate heat stability. Ifv the lauric acid componentris replaced by amixture ofvnapvhY tlhenicV and myristic acid (9c) ,Y thegel .is stringy: but lacks body. Replacement of the lauricy acid and coconut acids by Z-ethylhexoic acid (9dr results in a gel of generally satisfactory characteristics. Example 9j illustrates thelpo'ssib'ilities in the way of employing as the aluminum soap component material entirelyoic syntheticcri'gin; the mixture of acids used" isniade by the addi-V tion ofsodiurn toynaphthalenel, followed'by .oar-v bonation with carbon dioxide. `The gel prepared with this soap alone in combination 4with Neo--L Fat 3R. is too stringy and brittle to befully satisfactory, .but the combination has great bodying power. f

EXAMPLE Field filling vof a bomb with a gel from'alumz'num coconut soap, Neo-Fat 31%,'v Zcm'pblac'lc cmd gasoline f I A three-gallon canfwith calibration markings is filled to therst mark with 3.83 pounds of aluminum coconut soap 'and 0.85 pound`r of lampblack' is Vadded to the next mark, and thev twoV powders are well mixed. [A crimped cover, having a few 1" perforations on one side, is put in place and the container is grasped by a handle running along the side and the contents are shaken into 5.65 gals. of gasoline contained in an eight-gal. metal pail which has.l suitable calibration markings. During the addition of thepowder, the gasoline is stirred with a wooden paddle; A thin, even suspension results and this is poured into the bomb through a large funnel. A 2-qt.vr

screw-capped tin can containing a mixture of Neo-Fat 3R (2.58 pounds) and suflicient gasoline to keep it from solidifying at low temperatures (0.15 gal.) is opened and the contents poured into the bomb. A screw plugis inserted and the bomb is tumbled a few times andlet stand at a temperature of 15 C. or higher.v Ini GELATION on vvaincus Y EXAMPLE. 11

Thickeners prepared as the coprecipitated aluminum soaps from:

ANALYSES OF THE NUT OIL ACIDS Palm Coconut vBabassu Kernel 271. 7 261. 5 259. 0 270. 6 260. 2 258.2 23. 5 22. 4 23. 1 lod. No 8. 2 17. 5 17.0 Unsap. percent 26 28 O. 30 Probable lauric, percent 47. l 4l. 9 50.0

The samples were dried toa moisture content of V0.5-2.0%, as determined by the loss in weight on drying at 23-30 mm. pressure at |70 C. for 48 hours. The average ash content is 13.2%, and the average aluminum content, determined by extraction of a petroleumV naphthagel with nitric acid, 'conversion to the sulfate, precipitation with ammonia, and calcination at 1200o C., is 5.9%. Samples exposed to air for 15 hrs. at 60 C. showed no loss of solubility in hydrocarbon solvents or in gelling eiciency. In Table IV, coconut acid, babassu acid and palm kernel acid, are compared for the stringiness and viscosity which they impart to incendiary gels.

TABLE rv.-1NsPEoT1oNs 0F 12 PERCENT GELs IN STANDARU' GASOLINE (11.5 REID V. P., ANILINE POINT F.)

HYDROCARBON FUELS WITH `SOAP 1`1a (TABLE IV) Solvent Per cent Thickener Gelaton Time R. l?. M./

Min.

650 g Remarks Gasoline Full-bodied, tough. Slightly thinner. Rather short.

Very tough.

Good, tough stringy. Very thin.

Very tough.

Good, tough stringy. Very thin.

tial gelation occurs in 1A; to 1 hour, depending uponthe temperature,- andthe gum becomes v stringy and ready for use in 10415 hours.'-

AIt is'evident that the time required for gelation variesgreatly With structure of the hydrocarbon, and also that with aromatic and cycloparafdnic EXAMPLE 12 Thickener prepared as the coprecipitated aluminum soap from:

2 parts-coconut oil acid 1 part-unrened naphthenic acid 1 part-oleic acid The soap, obtained as a dry, dark brown powder, has considerable bodying power; for example, a 12% gel in standard gasoline is comparable in viscosity with those described above in Example 11 (Stoermer R. P. M./650 g.=0.095) A1- though suitable for some purposes, the gels from this soap lack strength and are not well adapted tov use in bombs and shells. This deficiency is easily recognized from the results of drag tests with 13.5% gels. Those from soaps 11a, 11b and 11c-of Example 11 show times of fall.of 17, 12 and 27 sec., respectively, and the plunger retains an amount of gum in excess of 9 g. With the gel from soap 12 the test bottle falls free in 2 seconds and retains only 2-3 g. of gum. Werconsider a gel to have passed this test (at 77i2 C.) if the time of fall is at least 10 seconds and the weight of sample adhering to the plunger at least 91g.

EXAMPLE 13 Thickeners prepared a-s the coprecipitated aluminum soaps from:y

2 parts-special fatty acid fraction l partnaphthenic acid (refined) 1 part-oleic acid TABLELTSM GELS IN; STANDARD GASOLINE Time at 77"F.V Soap Nature ot the Satd Fatty- No. Acids D' IS- persion Setting 11a Approx. 50% lauric 7 17 13a.- More than 50% lauric. .7-.. l 34 l --do 1% 5 '29 2 As in other instances, the dispersion and setting times can be extended considerably, if desired, by compression ofthe solid soap to reduce the porosity, and also by increasing the particle size.

Another characteristic of the soaps prepared from saturated acids rich in the lauric component is that the amount of thickener required to produce a given viscosity often canY be substantially reduced beyond that observed with the total nut oil acids. This and other'characteristics of the soaps in this series are illustrated by the following descriptions: v l' A freshly prepared 13.5% gel from soap 13a (Wecoline AAAR) in gasoline is somewhat short, but after ve days acquires excellent characteristics, being very tough and reasonably stringy and tacky. No breakdown, thinning, or deterioration has been indicated in heating tests conducted at 66 C. for periods as long"as700 hours. The concentration of thickener canbe reduced to 12% (but not lower) and thegum will still meet the specifications for 13.5%' gels dened above by the drag test. With a soap utilizing total coconut oil acid, for example, No.' 11a, Example 11, the concentration often canfb'e reduced to 11% but not 10%.' .i

TABLE V.-HIGHLAURIC FATTY ACID FRACTIONS l No' Designation Description 81: .I

FROM COCONUT OIL 13a*... Wecoline AAAR Residue from l the stripping of 234.0 254. 5 25. 6 9. 2

lower acids (10%); contains about 8% glycerides. l'3b*-. Drew Special Sample. Tolsal distilled acids plus 7% -233. 9 268. 7 23.0 7.6

y g yccri es. y 13c*.' WVecoline AB.. Distilled Wecollnc AAAR '251.2 252.6 v 25.4 12.7 13 Wecoline AAB High lauric cut 246.9 249.1 25.2 14.8 13e". W. C. Smith.. Laurie and higher acids... '258.0 259.2 27.9 8.9 13f*;.. W. C. Smith.. Laurie-myristic cut 268.8 .268. 9 31.9 0. 7

FROM ANIMAL OR VEGETABLE 1313*--- Neo-Fat 11 90% lauric acid 279. 5 279. 7 37. 8 1. 0 13h.... Neo-Fat 13 ....v. 90% myristic acid 248 248. 2 51 2. o

VVFROM FISH oILs 13i* WCS Sperm Oil Cut 1 91% Laurie Acid. 273.0 37.2 0 l3]`*- WCS Sperm Oil 011132 75% Myristc Acid.- 238. 6 240. 8 43. 0 3. 8 13Ic WCS Sperm Oil Cut 3 .20% My'ristic, 76% palmitic 220. 7 224. 0 49. 2 7. 8 l3l* WCS Spermaceti Acids .15%1auric, 32% myristic 215.1 224.0 43.4 11.0

One characteristic of soaps compounded with acid fractions of lauric acid content higher than the nut oil acids is an increased speed of gelation and setting in hydrocarbon solvents, as is evident from the following Table VI.

-..Soaps 13b f are Very -pared with less thickeni kgagcgit. an'1'1% gasoline gelj more than "mee 'ments "or the prag test"` (timev lor r 'speccation' is f stillmet Wit In comparison `yvithV tire@ laune acid; soap 131; frcm'ieoafnyristi 4less. s u factory. 13.5% fvsatisiajctory "properties at lr 'gasoiinetnas per-at eV r vlarV 'superiorityof l u able-...156m 131.4 i' has hiehhodyine'n 'what superrft soap isain predominates; houleverth eI" 1115.155! factory; asi soapi vvh "el iriadeupj byL yri's'tic' d. So'apfl'cl which' vha'sfa ow, A eiitfa'njdtcontans no lauric,` isdeitelyless satisfactory.

EXAMPLE 14 'Ihickeners prepared asVVV the coprecipitated aluminum soaps from; L 2 partscoconut oil acid 1 part-naphthenic acid 1 part--special acid component Although-*oleic acid abundantly available and. is 'a yWholly satisfactory 'com-poneiitg a-A brief survey. v"is Vrecorded herein 1 the adequacy oi' various.substitutercompon ts 'I Yhe soaps were evaluatedibythe inspecti iii- 13.5% gasoline gels atE room-temperature, -HP' C. and 66 C., and the conclusions may be"V sf l'rilarized as -follows in Table VII:

Preparation of a gel suitable for burning annual weed seeds from:

75 parts- Stoddard solvent or kerosene parts-gasoline 1.5-2.5 parts-aluminum soap, Example 7 V'The soap is stirred with the mixture of fuels until the particles are solvated suiiiciently so they will not settle. After standing at ordinary temperature overnight, the gel is suitable for use. More hydrocarbon fuel is added if required to make the gel fluid enough to pour freely, for example through 11g-inch perforations in the screw cap of a dispensing container. Gels of this character are particularly suitable for application by spraying on crabgrass or other Weeds for the purpose of extermination by the burning of the seeds.

It will be realized from the nature of the invention that a number of substitutions and modiiications will be apparent to those skilled in the art Without departing from the scope of this invention. Accordingly, it Ais intended that all matter described and set forth hereinbefore shall with thefstate of the priorartgf. il Whatis claimed asriew 1". v`A'.co'nipo'sition of matter adapted to. thicken iight iquidmydrocarbon 'fuels' intojueendiary g'els lcomprisng in parts by Weightapproximately 1 to 1.7'part`sio the aluminum soap of fatty acids 'found in coconut oiLa'nd'V approximately one part of aluminum naphthenate.

` f 2. A'composition of matter-adapted to thicken lighty liquid hydrocarbon fuelsinto' incendiary gelscoiiiprising in parts by Weight approximately one part of the aluminum-soap ofy .fatty acids ffound in coconut oil-Q and approximatelfyito 1.25

partsoi aluminum oleate.

3. An incendiary gel comprising frumgebaut 84%- to about 92% by Weightof `gasoline thickerred with from about 2%- t abou t4 16% by Weight oi a com'positionv comprising in parts by Weight approximately 1" to 1.7 parteci-aluminum soap of-fatty acids. found V`in coconut oil, and approximately one part o faluminumrnaphthenate.

'4. An incendiary -gel comprising from about 84% to about 92% by Weight of gasoline thick- 'erred with from about 8% to about 16% by weight of a composition comprising `parts byweight Yapproximately one vpartfof'aluminum. soap of y fatty acids foundin coconut oil,` and approximately. to 1.25 parts of Valuminum oleate.

light vliquid hydrocarbonfuels into incendiary gels comprising in parts by weight approximately 1,to.1.7 parts ofY the .hyd-roxy aluminum soap of fatty. acids. found; coconut oi-l and approximately 1 parto hydroxy aluminum naphthenate.

'6l .A composition of matter adapted to thicken light liquid hydrocarbon fuels'into incendiary gels, comprising in parts by Weight approximately 1 part of the hydroxy aluminum soap of the fatty acids found in coconut oil, and approximately 1 to 17.25 parts of hydroxy aluminum oleate.v Y

7. A composition of matter adapted to thicken light liquid hydrocarbon fuels into incendiary gels comprising in parts by weight approximately 1 to 2.5 parts of an aluminum soap of a saturated fatty acid fraction having from 8 to 14 carbon atoms per acid molecule, and approximately 1 to 1.25 parts of at least one member of the group consisting of soap-forming naphthenic acid, soap-forming unsaturated fatty acids `having from 17 to 22 carbon atoms per acid molecule, and the aluminum soaps of said group of soapiorming acids.

8. A composition of matter adapted to thicken light liquid hydrocarbon fuels into incendiary gels comprising in parts by Weight approximately 1 to 1.7 parts of an aluminum soap of a saturated fatty acid fraction having from 8 to 14 carbon atoms per acid molecule and approximately one part of an aluminum soap of naphthenic acid.

9. A composition of matter adapted to thicken light liquid hydrocarbon fuels into incendiary gels comprising in parts by Weight approximately one part of an aluminum soap of a saturated fatty acid fraction having from 8 to 14 carbon atoms per acid molecule and approximately 1 to 1.25 parts of an aluminum soap of oleic acid.

10. A composition of matter adapted to thicken light liquid hydrocarbon fuels into incendiary gels comprising in parts by weight approximately one part of an aluminum soap of coconut oil acids and 1.25 parts of an aluminum soap of oleic acid.

5.- A composition of matter adaptedpto thicken cendiary gels comprising in` parts byiweightjapproximately 1.5 to 2.5 parts rof an aluminum soa-p of` a saturated fatty 'acid fraction having from 8 to 14 carbon atoms per acid moleculeand approximately one part of a mixtureof oleic and linoleic acids. K j' Y 'l j 13.- A composition of matter, in'powder form, adapted to thicken lightliquid hydrocarbon .fuels into; incendiary gels 'i comprisingin parts by weight approximatelyl to 2.5 partsjof an aluminum soap of a saturated fatty acid fractionv having from'8to 1 4'carb`on atoms per acid molecule and approximatelyl to 1.25l parts of atleast one member ofthe group consistingof'soap-forming naphthenic acid, soap-forming'unsaturated fatty acids having'from 17 to v22fcarbon atoms per'acid moleculeand the aluminumsoaps ofl said` group ofV soap-forming acids and al finely divided combustible sorbent material of the class consisting of comminuted carbon and comminu tedwood.

14. An incendiary gelcorriprising from about 84 to about 92% by weight of a light liquid hydrocarbon fuel thickened With'Af-rom-about 81% toabout 16% byV weight of acomposition@comprising'in parts by Weight approximately, lto 2.5 parts of an aluminum soap of a saturatedfattyacid fraction ,10 thicken light liquidhydrocai'bon :fuels` 'into in- "Cillafand approximtlirfl Adrocarbon' fuel] thickened comprising in partsl bygyv'ei'ght approximately 1 havingY from Sto 1 4 c xfbont atoms per acid molev '11.25 parts ofy at least one jm'embe'r' Voijtlige; group. consisting of soapforming ,naphthenic acid', soap-forming unsaturated fattyfac'id's'having" from` 17- toy 22 carbon atoms per acid molecule,l andthe aluminum soaps of. saidvgroup of soap-forming acids.

f15,. `incendiary' gel comprising from about 84.130A about 92% byu/eight f a'. light liquid lhywith 'a composition to` 2.5v parts o f angaluminumjsoapof a saturated Number Name Date 123,683 Dennis Feb. 13, 1872 488,223v Rogers ,.-.g i- Dec. 20, 1892 1,936,632, j; Lededer. -NOV. 28, 1933 2,264,353 VZimmer et a1. Dec. 2, 1941 2,343,736 1 :Beerbower etal. -Mar. 7, 1944 2,365,037 Zimmer et al. Dec.12, 1944 2,390,609 Minich Dec. 11, 1945

Claims (1)

14. AN INCENDIARY GEL COMPRISING FROM ABOUT 84 TO ABOUT 92% BY WEIGHT OF A LIGHT LIQUID HYDROCARBON FUEL THICKENED WITH FROM ABOUT 8% TO ABOUT 16% BY WEIGHT OF A COMPOSITION COMPRISING IN PARTS BY WEIGHT APPROXIMATELY 1 TO 2.5 PARTS OF AN ALUMINUM SOAP OF A SATURATED FATTY ACID FRACTION HAVING FROM 8 TO 14 CARBON ATOMS PER ACID MOLECULE, AND APPROXIMATELY 1 TO 1.25 PARTS OF AT LEAST ONE MEMBER OF THE GROUP CONSISTING OF SOAPFORMING NAPHTHENIC ACID, SOAP-FORMING UNSATURATED FATTY ACIDS HAVING FROM 17 TO 22 CARBON ATOMS PER ACID MOLECULE, AND THE ALUMINUM SOAPS OF SAID GROUP OF SOAP-FORMING ACIDS.

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