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Publication numberUS2768072 A
Publication typeGrant
Publication dateOct 23, 1956
Filing dateAug 15, 1955
Priority dateAug 15, 1955
Publication numberUS 2768072 A, US 2768072A, US-A-2768072, US2768072 A, US2768072A
InventorsHoward J Stark
Original AssigneeHoward J Stark
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of producing a low density explosive
US 2768072 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Oct. 23, 1956 H. J. STARK METHOD oF PRoDUcING A Low DENSITY ExPLosIvE Filed Aug. 15, 1955 5 Sheets-Sheet 1 MM LV m0 ZOFDJOm l INVENToR. )'14 HOMIRD J. STA/'7K ZA TTORNE'Y w Oct. 23, 1956 H. J. STARK 2,763,072


1N VEN TOR. How/mo .1. sun/r BY Z fig@ f A T TOR/VE Y Oct. 23, 1956 H. J. STARK METHOD oF PRoDUcING A Low DENSITY ExPLosIvE Filed Aug. 15, -1955 5 Sheets-Sheet 3 FIG. 9.

FOAMED EXPLDSIVE INVENTOR. HOMRD J S TARK Z ATTNEY United States Patent AME'IFI-IODT OF IPRODUCIN G .iA-'.:ILOWfDEN-SITY :EXBLOSIVE The invent-ion -described herein 'ma-y ibe :manufactured and use'd Abyor ffori'theGovernmentof thefUnitedStates -of America for fgovermentl purposes `Withoutlthe fpayfm'ent'4 o'f v any1 royalties Jthereon: or therefor.

This invention relates to low density explosives andfin particular to the process ofmanufacturing -a-low'density, cellular explosive foam.

Thisis ajcontinuation-in-:par't applicationo'f copending application Serial No. 300,367, `tiled June 30, 1952, and lentitled VMeth-od -of Producing a vLow -Densit-y 'Explosive which was a divisional application of Serial No. 185,900, filed September 20, 1950,. and rentitledLowiDensity- Gelhl- `lar Explosive Foam .both of =whichrapplications are now abandoned.

The general object of the invention is -to fprovide an .explosive having a cellular foam structure whichbecause 'of such foam structure, is of relatively`low-;lensity,is '.buoyant with respect to water, and of'greaterr-and more rapid shattering eiect'than thesame weighto'fliigh density explosive.

It is also an object ofthezinventionto provide Van ex- .plosive having.acellulanoamstructure which is set and rigid Y,and .which is `relatively=strong.and r tough,

.-Ittis a further object of the v4inventiion ,providaan explosive having ar-cellularifoam structure whichlnayhe .castior molded zinto la particular. shapetpiior. tothe setting or assumption of rigidity. v A

.Other :objectives -will tbe..apparent1from ,the .following Idescriptionand fromrthedrawingsrhereto attached, fwhich are,illustrative\of .the method `of .making `the cellula'rrexplosive and .of-` the preferred .embodimentsoflhel invention.

.In these drawings Fig. 1 ,is .allowrchart .of the `dynamic `air-setmethod Yof .this invention; Y

Fig. 2 is a llow chart ,of the chemicalblowinmethod of this invention;

Fig. 3 is a diagrammatic transverse ,section through La conventional floating mine;

Fig. 4 is a diagrammatic transverse .sectiontthrough ia floatingmine .of the '.typeillustrated .bysEig but containinga relatively. large =quantityro'f.theifoametl explosive `of -this `invention {..cast lin situ;

Fig.,5.=is ,a diagrammatic sectionalzelevational view-.of aoatingmine `in Ywhich ihershelllis -,.coinprise'd of the molded foamed vexplosive .of this 'invention encased `in .light weight metal.onimpregnatedfabric .and shows-.fthe increased` highexplosive 'charge rpossible @with this ,typeof construction;

.-.Fig..6 is .a.diagramma'ticlongitudinal:section 'through .a.'loating,: harbor Amine showing .the .combination in ,the explosive chargetothe.conventionallliigh ddensity explosive with the'foamed explosive ofthis'invention;

1"Fig, T7 `'is aAdi-agrarnmat-ic longitudinal =sectionleleva tional View of a torpedo carrying a charge of high/density exp lesive andi foamedrexplosivetoffthisi invention; Land Figs. 8 and 9 are a diagrammaticflongitudinalssectionalelevationalsview;:anda.-transversefsectionalViewtakenfon line 9-9 of Fig. 8, respectively,totfafradioteontrolied 7 given Volume.


2 homing vessel 'showing the lfoametlexplosive of this `mventionfcast:and molded'within tthe'structure of the double walled fhull. l

Heretofore, l`it; `hasbeen'the-practice,in the manufacture of explosives, 'topro'duce lthem with a relatively high density in-order tto have -a great explosive effect in a i' Now -fa 4requirement Vhas arisen in which nitisdesirable tohave'ean'explosive which is buoyant and `which may 4have a Jgreater explosive `effect which `may beaiditivelto that ofrtheeonventional high `"density explosive. 'This requirement "ispresentnot only in rfloating mine -structures, but -also in wrthe guided surface (the -so-callefl homing) vessels. i'

Il-iis inventorhas met this `requirement by providing a vfoarntype explosive vvliii'zhfesem'bles "in5phy'sical ap- -pearance and-.characteristics cellular polystyreneforcellu- .larA acetate. It-is rc'el'ativestrong andtough anlthe'density thereofcan "be varied by formulation within the range \of-`from"bout 5 -to about "501pounls perI cubictfoot.

'Thecellsefltheifoamed -andfset structure of vthe-ex- =plosiverare substantiallynon-communicating and referred to as closed-cells in contradistinctionlto spongy open-cells. rTherefore, aunlde'dplate dfithis material-iisfrelativlyimpervious to Agas `and awater. 'In comparison with blsa rwooLvi/hieh hasfafbuoyancyof abouttwentylpounds per cubic foot after twentfwfour hours `immersion under -a Vten ffoot head Lof '-water, this 'cellular explosive has e. ibu'oy-ancy of from-aboutZO to about 50pounds per 'cubic foot under similar conditions.

The Efollowing fexplosives, as -well x-as others, can fbe preparedinfoamv'orlcellularform: `r(.1) lrinitrotoluene (2-) y,Nitnocellulose (tri, ,hexa ,and rdodelta. nitrocellulose) (3,) Rentaerythritl Y f (4) RDX l(cyclo .trimethylenetrinitramine) Thefoamedeexplosive rconsists essentially of vanyJone-of -the above-.explosives ^bondedfby Va ffoaming. plastic.

A 'foaming plastic is :a `plastic Iwhich-will 'be of solid cellular structure when fit is allowed to ysetrafterbeing foamed either by chemically or mechanically blowing gas or :lair through it iwhjle in the liquid `stagems will rappearinthe -examplessset'forth belo '.'This .inventor :has rfound `that :polyesters .of :ethylene :glycolr-maleic:anhydride intermixed \with :monomeric :styrene is ideally suitedlasi afresininfthe carryingaouty ofithis iinvention. VThis:resinziszshown and described salong'with :other resins wvhich also are suitable .in Carleton .Elliss f-Pa-tent;2',255,3'13,which is incorporated byi reference and forrns :a 4apart :of ithisrfspecilc-ation; Of :course .a ller .as used in :the examples :of Ellisfs unnecessaryand not `used -althoughisuchusewould stillffall witliinithefscope: of what is considered to bethe @present invention.

An example` 'offone of these fresins is 'that'.pro'duced@ by fheating 5.00 partsof maleic anhydride. and 541gparts'diethylene glycolineanoillbath at.220-.22`5 C. vfor'7 hours 'awhile bubbling nitrogen igas therethrough to provide i an inert atmosphere. The.diethylene.g'lycol maleateiformell =is a Ilight-colore'd iviscous :liquid `of acid :number 7.1. .Eighty-five .tparts Lof. this :liquid :arernilxed with 5 parts 'monomericistyrenet in -fa glasszeontainer .with a mechanically isdriven :stirren The iresultant :liquid 'is 1a satisfactory -stocka solution andrhas 35% tttbyzweight) benzolrpernxide ('curing agent) uand 1/2;% 1.(.by weight) cobalt'naphthanate .(aceeleratoryfaddedto it iustzprionto: itsuse.

These bonding thermosetting polyester resinslarefwell known in the Liield i o f :resin chemistry :and their specific :compositions Vformfrrorpartof thistinvention. Thezrequirements'thereofe-are:thatfthey be compatible Withisolutions .ofV the explosives, lthatathey gel; atroom temperature t in a relatively:- short .period .ottime about fteen min j tutes, `set ypermanently Y: in .about `one thour .and A.that Y.they

impart a viscosity to the solution of the explosive sufficient to prevent the escape of air therefrom and yet be sufficiently fluid for efficient molding and casting. The rate of setting of these resins is controlled by the addition thereto of a relatively small proportion (from about 2% to about 4% by weight) of an appropriate curing agent. Such agents have been found to include: benzol peroxide, ditertiarybutyl peroxide, cumenehydro peroxide, methylisobutyl ketone peroxide, and dibenzaldeperoxide. The choice of the particular curing agent used depends upon its compatibility with the solution of the resin and the explosive and the rate of curing desired. Also an accelerator, such as cobalt naphthanate may be added in a proportional amount of from about 2% to about 5% by weight to give additional control on the rate of gelling and setting of the resin. These curing agents and accelerators are herein referred to as setting agents.

Commercially available resins which have been found to be suitable as a bond for the foamed explosives of this invention are MR-28C and 29C by Marco Chemicals, Inc., Selectron 5003 and 5016 produced and marketed by the Pittsburgh Plate Glass Company, Laminac 4128, 4129 and 4116 produced and marketed by the American Cyanamid Company, and Paraplex P-43 by Rohm and Haas Company.

Two methods of the preparation of foamed explosive are preferred by this inventor. These are (1) the socalled dynamic air-set method, and (2) the chemical blowing method. These methods differ from each other mainly in the method of introduction of air or gas into the resinous solution of the explosive. In the dynamic air-set method (reference being had to Fig. 1 of the drawings), a solution of the explosive in styrene, ether, acetone, or a mixture of some o-f these or other solvents is made as indicated yat 10. Only as much explosive may be dissolved as will go into the solution with or without the application of a moderate heat, and with staying below the decomposition temperature of the explosive. A solution of a foaming plastic such as a polyester type resin, a curing agent or catalyst and an accelerator is prepared as shown at 12 in the proportionate amounts above indicated. Frorn about to about 30% by volume of the liquid resin solution is mixed with the solution of the explosive as shown at 14.

As an example, the diethylene glycol maleate with monomeric styrene is mixed with benzol peroxide and cobalt naphthanate as specifically set forth above. About 20% by volume of this solution is mixed with a saturated solution of TNT dissolved in styrene.

The curing agent and accelerator will cause the resin to gel in about 15 minutes and to set permanently in about one hour. The mixture of solutions of the explosive and resin is stirred for about 5 minutes as indicated at 15 and allowed to rest for about 5 minutes. Compressed air from a source (not shown) is introduced into blowing chamber 18 and thence through forarninous member 20 which may be a glass frit or metal screen of a mesh in the range of from 75 to 300 and through the mixture at 14 for about 3 minutes which will foam the said mixture. The foamed mixture is then poured into molds or other containers within the remaining 2 minutes of the 15 at which time the foamed explosive gels or sets up and in one hour becomes a hard cellular mass. By a proper control of the viscosity of the mixture, above referred to, air bubbles do not appreciably escape therefrom after the completion of the blow or during the period that the `mixture is in the mold prior to gelation.

There is therefore no collapsing of the foamed structure in the mold.

In the chemical blowing process the explosive is dispersed in a suitable solvent such as acetone or styrene as indicated at 24 in Fig. 2 to obtain .a saturated or highly viscous solution. A solution is prepared by the addition of a curing agent and an accelerator to a foaming plastic in the proportionate amounts above indicated and as shown at 26. The foaming plastic may be a polyester type resin as above described yor other foaming plastics set forth below. In either case they are adjusted to gel in about fifteen minutes and to set in about one hour as in the process above described. The solutions of the explosive and the resin are conducted into mixing chamber 28, the solution of the resin being added in the proportion by volume of from 10% to 30%. In this chamber there is added to the mixture from 10% to 30% by volume of a chemical blowing agent such as diazoaminobenzene or toluene diisocyanate. The mixture is stirred, as indicated at 30 for from five to ten minutes and is then poured or cast into molds as indicated at 32. T he molds are then heated as indicated at 33 to :a temperature of about C. but not above decomposition temperature of the explosive at which temperature the blowing agent evolves a relatively large volume of gas which causes the mass to expand forming a cellular structure.

The range in composition, on a percentage weight basis at various temperatures of formation, of the foamed explosives of this invention is given in the following table:

Percent Percent Percent C. Solvent Range in Explosive Range in Range in Temp. Comp. Comp. Comp.

of Resin acetone 10 T. N. T. 80-(20 10-30 40 T. N. T. 50-30 10-30 30 T. N. T. 60-40 10-30 5-10 T. N. T. 85-00 10-30 5-10 T. N. T. 85-60 10-30 5-10 T. N. IT. 85-00 l0-30 5 T. N. T. 85435 l0-30 70 PETN 25 5 50 IETN 40 10 60 PETN 30 10 25 cyclohexanone 78 RDX l2 10 60 acetone 67 RDX 18 15 cyclohexanone. 60 RDX 25 i5 .do 78 HEX-1&2 12 l0 60 acetone. 67 HEX-1&2 18 l5 97 cyclohexanone. 60 HEX-1&2 25 15 Other examples using different foaming plastics are set forth below and it will be understood by a chemist familiar with the art that such foaming plastics are capable of use with the dynamic air-set method as well as the chemical blowing method.

A chemically blown foamed explosive can be prepared by using toluene diisocyanate and alkyd resins to produce a composition referred to in the art as polyurethane foam resins. Carbon dioxide is liberated in the reaction to cause the plastic to foam and thus, in effect, the ingredients act as their own blowing agents.

For purposes of this invention an alkyd resin having following composition is prepared:

7.6 parts by weight glycerol 5.0 parts by weight adipic acid 1.0 part by weight phthalic anhydride These ingredients are refluxed in a glass lined container in an atmosphere of carbon dioxide and at a temperature of about 165 C. until an acid number of about 55 and hydroxyl number of about 415 are reached. The alkyd resin thus formed is then cooled to room temperature for further use as described below.

Ratios of explosive to resin by weight range from 10% resin to 90% explosive to 50% resin and 50% explosive. Optimum results are obtained where 10 to 30% of resin is used with 90 to 70% of explosive. The following composition is prepared in the following manner to produce a polyurethane explosive foam:

(A) 150 parts by weight of alkyd resin as prepared above.

(B) 1350 parts by weight of TNT contained in warm acetone (about 30 C.).

(C) parts by weight 2-4 M-toluene diisocyanate.

(D) 58 parts by weight of water.

Ingredients. (A) and.(B) areiirst mixediin azmechani.-A cal mixer such asea `l-Iobartofsuitable capacity.v Then ingredient (C) is mixedftherewith followedlby'ingredient (D) which'is mixedtherewith or stirredrfor. about 20 minutes.`

This mixture is -then poured into a suitable metal mold calculated to produce. the desired' density'which infthis case is about l pounds per cubic foot. The closed-mold containing the mixture is then placed in a hot-air` oven at about 73 C. for about'one` hou-r afterwhichthe mold is removed fromtthe hot oven andcooled to room temperature andthe explosiveTNT foam` is.` removed therefrom.

Another example of a manner of practisingL the invention, which in this `case utilizes a polyvinyl chloride resin with a copolymerofvinyl'chloride and vinyl acetate, follows:

About 100 partsof a polymerized material consisting of about 85% by weight 'of .polyvinyl chloride and yabout byV weightof copolymers Aofvinyl chloride and vinyl acetate are mixed in aHobart-mixer withaboutf80 parts of tricresylphosphate (plasticizer) until thepolyrner is thoroughly dispersed. Aboutt` parts of` P..Poxybis benzene sulfonyl hydroxidel (chemical blowing.- agent) is then added and mixed thoroughly. (Diazoaminohenzene or 40% dinitroso pentamethylenetriamine'mayy also be used as chemicalvblowingragentsi) About 3 partslof lead stearate (stabilizer) is also added and'mi'xed thoroughly.

About 80 parts by` weight ofTNT inxatne stateof divison such as will pass through a Standard Sieve No.

50 or 100 (as dened by theAmericanz Society for Testing Materials Standards) visth'enadded to the above composition and the mixture worked-to'. a uniform consistency with astil blade mechanical mixer. About 10% by Weight of the combined'ingredientsl of acetonev isv then added slowly and the mass mixed .to uniform consistency.

A suitable charge or volume' of 'this product is placed in a steel mold of tdesired shape.4 Such anzexamplefwould be a mold6. x 6 x 1/2 ofheavyv steel wall construc-V tion as established inthe art or industry for processing. these products. The mold cavity is completelyiilled, and the chargedmold` placedV in` between press'platens at a temperature of about 160 C. The: press is then closed and about 5000'p. s. i.' pressure appliedtov the mold and held for about 20 minutes at this temperature. After this time the pressure is reducedto atmospheric and the mold removedfrom the press. The mold is opened and the molded piece is removed. It isthen placed in a-hot air oven or chamberat about 120 C. for about 60 minutes when the piece willthen grow or' expand to about double its volume producing a density between 4 and 7 pounds per cubic foot. The density canl be considerably changed by varying the charge into Vthe mold and the weight of explosive incorporatedinto the mold.

An epoxy resin can be used in carrying out the invention in a manner'such as shown by the-specific example below.

About 110 parts of a diphenol suchv as bisphenol Av is dissolved in 80 partsthereofof a 20% water solution of sodium hydroxide. About 188 parts of epichlorhydrin is slowly added to the mixture at about 75 C. over approximately a 30 minute period. The resulting resin melts at about 65 C.

Explosive foam mixture is prepared using the following ingredients:

Epoxy resin as above-98.0 parts.

Ammonium bicarbonate (blowing agent)-10.0 parts. Diglycol laurate S (wetting agent)-3.S parts. Piperidine (curing agent)-2.0 parts.

TNT-400.0 parts.

Epoxy resin as above is heated to the liquid stage at about 75 C. The ammonium. bicarbonate previously dispersedin .diglycol laurateS is .then added and stirred thoroughly. TheTNTisthen added and stirred, fol# lowed by thepiperidinewhich is then added'andmixed for about 5 minutes. Theliquid phase life at this stage is` limited to ab0ut.30..minutes; otherwise, polymerization or solidiication sets in. The mixture is then transferred to a heated metal mold or box held at about 75 C.t for about 2V hoursV when the explosive foam is made. The

explosivecompletely lls the container. Of coursethe explosive foam mixtures may also be made from nitrocellulose, pentaerythritol, amd cyclo trimethylenetrinitramine. Thedensity of the explosive foam iis controlled by varying. the. percentage of explosive going into the composition and the weight .of -mix goinginto the heated mold cavity vor box as describedabove.

This particularexplosive foam composition may also be cured using other amine reagents such as diamines, triamines orquaternary amines such as, diethylenetrif amine: Vand triethylenetetramine. Commercial resins such as Shell Chemical Company Epon resins such as Epon 834, Epon-8643 and .Epon 1001" andmixtures of these various resins may also be used.. Cure or harden-V ing-is accomplished by using any one of the amines stated above.

Referring further tothe drawings,l in Fig. 3 a conventional'oating mine isy shown diagrammatically. and generally at 40. The mine comprisesa metallic case 42, Contact elements 44 which are in electric Vcircuits 46 with the detonating or exploding device 48. This exploding device detonates the charge of high explosive 50- when any one of the elementstd is` actuated by contact Awith an object in the water. Theinterior volume ofthis type of mine is comprisedofabout 50% Aair space. as shown at 52.

In Fig. 4 the air space of the mine-.shown in Fig. 3 is -lledwith the foamedV explosive of this inventiontas shown at 54 which. has been cured and set in. place. This foamedor cellular explosive notonly gives an additive effecttothebrisance? of the high-explosive, but in the event of leakage through metallic shell erosion or corrosion thereof, .the buoyancy of themine will be.

mine may-be lled with high density explosive therebyV producing a mine of greatly increased shattering eifect when also considered in the light of the additive explosive effect'of the cellular explosivecomprising the shell.

Fig.` 6"is a sectional illustrationof a lloating harbor mine showing the arrangement of a metallic casing 60, a high density explosive charge 62?.,k detonating or exploder device 64, actuating contact element. 66 and foarned explosive of this invention 68y surrounding the high .explosive charge and exploder'device and lling .the normally present Within fthe .casing of this type of mine. ln the event of leakage of water through the casing due to corrosion thereof or otherwise, the foamed explosive prevents loss of buoyancy andthe normally resultant loss of the mine.

Fig. 7 is a sectional-elevational view of a torpedo shown generally at 70 in which the foamed explosive 72 of this invention lls the normally present air-space within the shell 74. The legends in this ligure are believed to be self-explanatory. In this embodiment of the invention, the overall buoyancy of the torpedo is less than that of the torpedo having the conventional air space. But the total shattering etect of the explosion is much increased by this additional quantity of foamed forces the structure.

high explosive. In charging this cellular explosive into this air space in the torpedo, the foarned explosive is poured into this space immediately prior to the gelling thereof. The space is completely filled and upon the curing and setting of the resin component the cellular explosive becomes rigid and reinforces the sidewalls of the shell.

Figs. 8 and 9 show the application of the foamed high explosive of this invention to the structure of an electronically controlled homing vessel in Sectional-elevational views. Here the double walled hull 90 is shown provided with radio control 92 for motor drive mechanism 94. High density high explosive 96 substantially fills the interior of hull 90 surrounding the exploder device 98. The detonating contact element is shown at 99. The space within the double wall structure of the hull is tilled with the foamed high explosive of this invention as shown at 100. As in the case of the torpedo above-described, the foamed explosive is poured into this hull wall space immediately prior to the gelling and after setting the foamed cellular explosive mechanically rein- The advantage of this type of construction of these homing vessels is that the shattering effect of the explosion is greatly increased and that in the event of leakage through the outer wall of the hull due to corrosion or to any other cause the buoyancy of the vessel is maintained.

It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

l. The method of making a high explosive which is less dense than water comprising the steps of dissolving an explosive selected from the group consisting of trinitrotoluene, nitrocellulose, pentaerythritol and cyclo trimethylenetrinitramine in from about to about 80% by weight of a solvent selected from the group consisting of styrene, acetone, toluene, benzene and cyclohexanone, adding thereto from about 5 to about 30% by volume of liquid polyester resin to form a mixture, said resin catalyzed to gel in about fifteen minutes and to set permanently in about one hour, stirring said mixture for about tive minutes for homogenization, allowing said stirred mixture to rest for about tive minutes, introducing air under pressure for about three minutes in relatively fine streams into the mass of said mixture to cause said mixture to expand into a foam structure and pouring the said formed mixture into a molding space wherein said foamed mixture gels and sets permanently to form an explosive of a high degree of cellularity.

2. The method of making a high explosive which is less dense than Water comprising the steps of dissolving an explosive selected from the group consisting of trinitrotoluene, nitrocellulose, pentaerythritol and cyclo trimethylenetrinitramine in from about 5 to about 80% by weight of a solvent selected from the group consisting of styrene, acetone, toluene, benzene and cyclohexanone, adding thereto from about 5 to about 30% by volume of a liquid polyester resin to form a mixture, said resin catalyzed to gel in about fifteen minutes and to set permanently in about one hour, adding to said mixture from about 10 to about 30% by volume of chemical blowing agent selected from the group consisting of diazoaminobenzene, and toluene di-isocyanate, stirring said mixture for from five to ten minutes for homogenization thereof, pouring said homogenized mixture into a mold and heating said molds to about C. but not above decomposition temperature of the explosive whereupon said chemical blowing agent decomposes with the liberation of a relatively large volume of gas in relatively small bubble form within the mass of said mixture thereby causing said mass to expand to form a foamy structure thereof which immediately gels and sets as a rigid cellular explosive mass of relatively high strength and toughness.

3. The method of making a foamed explosive of low density comprising the steps of dissolving an explosive selected from the group consisting of trinitrotoluene, nitrocellulose, pentaerythritol and cyclo trimethylenetrinitramine in a suitable solvent to make a concentrated solution, mixing this solution with about 5 to about 50% of a foaming plastic in the liquid state to which has been added a suitable setting agent, introducing air into the mixture under pressure in relatively fine streams to cause said mixture to expand into a cellular structure and permit said cellular structure to set for a suicient time to solidify as a foamed explosive.

4. The method as defined in claim 3 where the foaming plastic is a polyester bonding resin.

5. The method as defined in claim 3 where the foaming plastic is a polyurethane resin.

6. The method as defined in claim 3 where the foaming plastic is an epoxy resin.

7. The method as defined in claim 3 where the foaming plastic is a polyvinyl chloride with vinyl chlorideacetate copolymer resin.

8. The method of making a foamed explosive comprising the steps of dissolving an explosive from the group consisting of trinitrotoluene, nitrocellulose, pentaerythritol and cyclo trimethylenetrinitramine in a suitable solvent tovmake a concentrated solution, mixing this solution with about 5 to about 50% of a foaming plastic in the liquid state to which has been added a suitable setting agent, having a suitable chemical blowing agent into the resultant batch, and heating said batch to a temperature below the decomposition temperature of the explosive and high enough to cause said chemical blowing agent to decompose and liberate gas whereby the batch is caused to expand to produce a cellular structure which sets to a solid foamed explosive.

9. The method as defined in claim 8 where the foaming plastic is a polyester bonding resin.

10. The method as defined in claim 8 where the foaming plastic is a polyurethane resin.

ll. The method as defined in claim 8 where the foaming plastic is an epoxy resin.

12. The method as defined in claim 8 where the foaming plastic is a polyvinyl chloride with vinyl chlorideacetate copolymer resin.

No references cited.

Non-Patent Citations
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U.S. Classification264/3.1, 149/109.6, 521/155, 149/93, 521/75, 264/46.6, 149/2, 149/92, 102/701, 149/100, 149/105, 521/178
International ClassificationF42B12/20, C06B45/00, F42B22/00, C06B45/10
Cooperative ClassificationF42B12/204, C06B45/00, Y10S102/701, C06B45/10, F42B22/00
European ClassificationC06B45/10, F42B22/00, C06B45/00, F42B12/20B4