US3227588A - Crystalline explosives in a viscoelastic binder of sheet form - Google Patents

Crystalline explosives in a viscoelastic binder of sheet form Download PDF

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US3227588A
US3227588A US351138A US35113864A US3227588A US 3227588 A US3227588 A US 3227588A US 351138 A US351138 A US 351138A US 35113864 A US35113864 A US 35113864A US 3227588 A US3227588 A US 3227588A
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explosive
composition
binder
weight
sheet
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US351138A
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Jones Walter Thomas
Wilby John
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    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
    • C06B45/04—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive
    • C06B45/06—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component
    • C06B45/10—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component the organic component containing a resin
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
    • C06B21/0033—Shaping the mixture
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S149/00—Explosive and thermic compositions or charges
    • Y10S149/11—Particle size of a component
    • Y10S149/115—Organic fuel

Definitions

  • Explosive compositions in accordance with the present invention provide explosive sheets that have suflicient mechanical strength to retain an imposed shape without support and suflicient flexibility to be bent through acute angles without materially cracking or breaking. Furthermore, these explosive sheets do not require coating either to provide strength or to remove surface stickiness.
  • a crystalline high explosive such as R.D.X. (cyclo trimethylene trinitramine), H.M.X. (cyclo tetramethylene tetranitramine), P.E.T.N. (pentaerythritol tetranitrate) or tetryl (2,
  • the term highly fluorinated throughout the specification and claims includes fully fluorinated. If there is less than 85% by weight of the explosive there is an increasing chance (particularly for thin sheets) that the sheet will not propagate a detonation. If there is more than 90% of explosive the sheet is brittle and lacks mechanical strength. The proportion of explosive is preferably between 87% and 89% by weight.
  • the explosive must be I present as a fine powder (i.e. at least 95% of the particles are less than 100 microns diameter) which has a bimodal particle size distribution so that a high degree of particle packing can be achieved with separation of the particles in the binder matrix.
  • the measured particle size distribution of a suitable explosive powder showed one peak between and microns and another between 8 and 10 microns while practically all of the powder had a particle size of less than about 50 microns.
  • the visco-elastic binder used in the explosive composition is a Bingham material whose response to stress conforms to the superposition of elements which obey Hookes elastic law and elements which obey Newtons viscosity law.
  • Visco-elastic substances which are preferably used as the main constituent are aliphatic hydrocarbon polymers, such as polyisobutylene or polypropylene, having a substantially linear polymer chain with lower alkyl side-groups.
  • Polyisobutylene is a satisfactory binder when its molecular weight is at least of the order of 5,000 (when measured by S'taudingers viscosity method); too low a molecular weight results in a sticky explosive composition that lacks mechanical strength.
  • the binder has a relatively high molecular weight it may be too viscous for ready incorporation with the explosive even in a water slurry, in which case the viscosity may be reduced by blending with a suitable amount of either a lower molecular weight polymer or a plasticiser.
  • polyisobutylene with a molecular weight of about 15,000 (Staudinger) requires the addition of about 20% of a plasticiser before it can be readily incorporated with the explosive.
  • Suitable plasticisers are aliphatic esters containing at least 15 carbon atoms and the esters of dibasic acids, such as sebacic acid and phthalic acid,.are particularly suitable.
  • suitable plasticisers include ethyl oleate, dibutyl phthalate and di(2-ethylhexyl) sebacate.
  • the presence of extremely fine particles (i.e. particles of less than 1 micron in diameter) of a polymeric highly fluorinated halocarbon in the binder of the explosive composition confers the ability on explosive sheets made of the composition to remain in contact with a surface without having excessive surface stickiness and generally enhances their mechanical and flexing properties. In particular, the resistance to tearing is increased and the chances of cracking during flexing are reduced.
  • Suitable fluoro-poly-mers are aliphatic polymeric fluorocarbons that do not contain any hydrogen but may contain another halogen, for example, chlorine and which are made by a suspension process so that they can separate in extremely fine particles in the composition.
  • Such compounds are exemplified by polytetrafluoroethylene, polyhexafluoropropylene and polytrifluorochloroethylene.
  • the preferred fluoropolymer is polytetrafluoroethylene (P.T.F.E.), which is available commercially (for example, grade CD3 supplied by Messrs. I.C.I. Ltd.) as a powder consisting of aggregates (about 500 to 600 microns in diameter) composed of individual particles, each about 0.1 micron diameter, so that the aggregates can be broken down in the final manufactured explosive composition.
  • P.T.F.E. polytetrafluoroethylene
  • the fluoropolymer is present in only a small proportion (at least 3%) of the visco-elastic binder there is some improvement in the properties of the explosive composition but proportions between 5 and 20% by weight, and preferably between 7 and 15% by weight must be added to obtain the best-results.
  • the fluoropolymer stifi'ens the composition so allowance should be made for this when determining the viscosity of the binder, especially for additions of more than 10% say.
  • a suitable overall viscosity value for the binder with the fluoropolymelr added is between 40,000 and 200,000 poises determined 'by the extrusion method using Mooneys equation at a rate of shear of 5sec. at25 C. V
  • Crystalline high explosives are not produced in the form of fine particles as required for the explosive composition and any treatment such as crushing the neat high explosive to produce fine particles is preferably avoided.
  • an explosive composition as hereinbefore described may be readily manufactured by forming'a mixed composition of the constituents in the required proportion and then repeatedly passing the mixture through differential rollers having a separation which is less than 0.01 inch, and is preferably about 0.002 to 0.003 inch.
  • the differential rollers in practice should be knurled as otherwise it is difiicult to pass the moist composition through the narrow gap.
  • the number of passes required to grind the explosive particles to the required size is reduced by decreasing the gap between the rollers and by increasing the difference between the peripheral speeds of the rollers which causes shearing of the particles. Between and 30 passes should be adequate if a gap of about 0.002 to 0.003 inch is used with a differential peripheral speed of the rollers of the order of three feet/sec.
  • This differential rolling also breaks down the aggregates of fluoropolymer particles and disperses the particles through the composition.
  • the explosive composition is then dried and can be formed into an explosive sheet simply by a final rolling between rollers separated by the desired thickness of the sheet which may in practice be down to about 0.08 inch.
  • a typical general explosive composition is:
  • the high explosive may be R.D.X., I-LM.X., P.E.T.N. or tetryl.
  • composition A which falls within this general composition is as follows:
  • Polyisobutylene (70 parts by weight) is stirred and heated in an incorporator to a temperature between about 90 and 100 C. Di(2-ethylhexyl) sebacate parts by weight) is added and the mixture stirred until a mix of uniform composition is obtained. A slurry of R.D.X. 88 lb.) and water (500 lb.) is heated to a temperature of about 95 C. and stirred at 200 r.p.m. in a mixing vessel. The plasticised polyisobutylene (10.8 lb.) is
  • the suspension is fiitered through a oambric filter to remove excess Water and the filtered material containing about 20% of water is thoroughly mixed with P.T.F.E. (1.2 lb.) in a Werner Pfleiderer incorporator in the cold for one hour.
  • the explosive composition is then passed repeatedly through a difierential rolling machine having knurled rollers rotating at different peripheral speeds so that there is a pronounced shearing action on the composition as it .passes between the nip between the rollers.
  • a suitable machine is a Torrance drum feed roll set to a minimum separation between its knurled rollers of 0.003 inch and having a 12 in. diameter roll rotating at about 15 r.p.m. and a 15 in. diameter roll rotating at about 60 r.p.m.
  • the peripheral speeds of the two rolls are thus about 50 and 250 ft./min. giving a differential speed of about 200 ft./min.
  • the composition is repeatedly passed through the rolls by the circulating drum feed for about five minutes, this being theoretically equivalent to about 25 passes.
  • the explosive composition is then finally dried in any suitable drier.
  • a Werner Pfieiderer incorporator may be used, for example, treatment lasting for about four hours at 95 C. or the composition can be left as thin sheets and simply dried in an oven.
  • the differential rolling machine may then be a Torrance Laboratory Roll through which the explosive composition is given ten passes with a minimum separation of about 0.003 inch.
  • the explosive sheets are made by passing the dried explosive composition through a rolling machine, having two smooth steel rollers of the same diameter, rotating at identical speeds, with the gap set to give the desired sheet thickness down to about 0.08 inch.
  • a flexible explosive sheet composition which comprises between and by weight of a crystalline high explosive in a fine particulate form with a bimodal particle size distribution which is bound in a visco-elastic binder of which between 3 and 25% by weight consists of extremely fine solid particles of a highly fluorinated polymeric halocarbon having a diameter less than 1 micron through said binder.
  • a flexible explosive sheet composition according to claim 3 in which the polytetrafiuoroethylene is present in a proportion between 5 and 20% by Weight of the viscoelastic binder.
  • a flexible explosive sheet composition according to claim 4 in which the polytetrafluoroethylene is present as particles of the order of 0.1 micron diameter in a proportion between 7 and 15% by weight of the visco-elastic binder.
  • a flexible explosive sheet composition which comprises between 85 and 90% by weight of a crystalline high explosive in a fine particulate form having a bimodal particle size distribution which is bound in a visco-elastic binder comprising at least 50% by weight of an aliphatic hydrocarbon polymer having lower alkyl side chains, between 3 and 25% by weight of extremely fine solid particles of a highly fluorinated polymeric halocarbon having a diameter less than 1 micron, and a plasticizer for the said hydrocarbon polymer.
  • a flexible explosive sheet composition which comprises between 85 and 90% by weight of a crystalline high explosive in a fine particulate form having a bimodal particle size distribution which is bound in a visco-elastic binder comprising at least 50% by weight of polyisobutylene, between 3 and 25% by weight of extremely fine solid particles of a highly fluorinated polymeric halocarbon having a diameter less than 1 micron, and a plas ticizer for the said polyisobutylene which is an ester having at least carbon atoms.
  • a flexible explosive sheet composition which comprises between 87 and 89% by weight of a crystalline high explosive in a fine particulate form with a bimodal particle size distribution which is bound in a visco-elastic binder comprising polyisobutylene and a plasticizer for said polyisobutylene and polytetrafluoroethylene in the form of extremely fine solid particles having a diameter less than 1 micron, said polyisobutylene and plasticizer therefor constituting between 10.5 and 11% by weight of the composition and said polytetrafluoroethylene constituting 1 to 1.5% by weight of the composition.
  • an explosive sheet composition in a process for the manufacture of an explosive sheet composition the steps of intermixing a composition containing to by weight of a crystalline high explosive in a visco-elastic binder containing between 3 and 25 by weight of a highly fluorinated polymeric halocarbon as extremely fine particles made by a suspension process, and repeatedly passing the mixed composition through differential rollers having a separation less than 0.01 inch, whereby the high explosive is ground into fine particles having a bimodal size distribution and the halocarbon is dispersed throughout binder in the form of solid particles having a diameter less than 1 micron.
  • a process for the manufacture of an explosive sheet which comprises the process according to claim 14 followed by a final rolling of the composition between rollers separated by the desired thickness of the explosive sheet.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Molecular Biology (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
US351138A 1963-03-14 1964-03-11 Crystalline explosives in a viscoelastic binder of sheet form Expired - Lifetime US3227588A (en)

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GB10115/63A GB1082641A (en) 1963-03-14 1963-03-14 Explosive compositions

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US (1) US3227588A (en)van)
BE (1) BE645178A (en)van)
CH (1) CH466777A (en)van)
GB (1) GB1082641A (en)van)
NL (1) NL142140B (en)van)
SE (1) SE353895B (en)van)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3296041A (en) * 1964-07-08 1967-01-03 Eastman Kodak Co Granulated crystalline plastic bonded explosives
US3311513A (en) * 1965-03-05 1967-03-28 Du Pont Nitramine, nitrocellulose explosive with ester plasticizer
US3326731A (en) * 1964-09-17 1967-06-20 Du Pont Detonating explosive in polytetrafluoroethylene matrix and preparation
US3338764A (en) * 1965-08-19 1967-08-29 Du Pont Flexible detonating compositions containing high explosives and polymeric metallocarboxylates
US3407731A (en) * 1965-08-19 1968-10-29 Du Pont Flexible detonating fuse
US3449179A (en) * 1966-09-07 1969-06-10 Asahi Chemical Ind Flexible explosive compositions containing block copolymers
US3496870A (en) * 1967-05-23 1970-02-24 Us Navy Spiral burning propellant charge
US3959042A (en) * 1973-11-21 1976-05-25 The United States Of America As Represented By The Secretary Of The Navy High impetus, low flame temperature, composite propellants and method of making
US3976522A (en) * 1971-07-26 1976-08-24 The United States Of America As Represented By The Secretary Of The Navy Nitroplasticized amine perchlorate flexible explosives
US5080735A (en) * 1989-03-03 1992-01-14 E. I. Du Pont De Nemours And Company Low flammability cap-sensitive flexible explosive composition
FR2723086A1 (fr) * 1994-07-29 1996-02-02 Poudres & Explosifs Ste Nale Procede continu de fabrication sans solvant de produits pyrotechniques composites
WO2016079453A1 (fr) * 2014-11-21 2016-05-26 Herakles Produits explosifs composites de faible epaisseur et leur preparation

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3006475C2 (de) * 1980-02-21 1986-10-30 Société Anonyme PRB, Brüssel / Bruxelles Treibstoff für Base-Bleed-Gasgeneratoren, Verfahren zu seiner Herstellung sowie zur Herstellung eines Treibsatzes aus diesem Treibstoff
GB2365420B (en) * 1988-05-11 2002-05-29 Royal Ordnance Plc Explosive compositions
SE501224C2 (sv) * 1990-05-29 1994-12-12 Bofors Explosives Ab Sätt att framställa polymerbundna sprängämneskroppar
US5187320A (en) * 1991-12-06 1993-02-16 E. I. Du Pont De Nemours And Company Fibrillatable PTFE in plastic-bonded explosives
RU2383518C1 (ru) * 2008-09-15 2010-03-10 Федеральное государственное унитарное предприятие "Российский Федеральный Ядерный Центр - Всероссийский Научно-Исследовательский Институт Технической Физики имени академика Е.И. Забабахина" (ФГУП "РФЯЦ-ВНИИТФ имени академика Е.И. Забабахина") Взрывчатый состав

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2999743A (en) * 1960-08-17 1961-09-12 Du Pont Deformable self-supporting explosive composition
US3102833A (en) * 1961-03-07 1963-09-03 Du Pont Process for producing a fibrous explosive having variable density
US3117044A (en) * 1957-03-18 1964-01-07 Charles W Sauer Solid propellant containing organic oxidizers and polymeric fuel
US3138501A (en) * 1962-06-18 1964-06-23 Eastman Kodak Co Method of preparing a cyclotrimethylene trinitramine and cyclotetramethylene tetranitramine plastic bonded explosives
US3173817A (en) * 1962-10-31 1965-03-16 Eastman Kodak Co Granular explosive molding powder

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3117044A (en) * 1957-03-18 1964-01-07 Charles W Sauer Solid propellant containing organic oxidizers and polymeric fuel
US2999743A (en) * 1960-08-17 1961-09-12 Du Pont Deformable self-supporting explosive composition
US3102833A (en) * 1961-03-07 1963-09-03 Du Pont Process for producing a fibrous explosive having variable density
US3138501A (en) * 1962-06-18 1964-06-23 Eastman Kodak Co Method of preparing a cyclotrimethylene trinitramine and cyclotetramethylene tetranitramine plastic bonded explosives
US3173817A (en) * 1962-10-31 1965-03-16 Eastman Kodak Co Granular explosive molding powder

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3296041A (en) * 1964-07-08 1967-01-03 Eastman Kodak Co Granulated crystalline plastic bonded explosives
US3326731A (en) * 1964-09-17 1967-06-20 Du Pont Detonating explosive in polytetrafluoroethylene matrix and preparation
US3311513A (en) * 1965-03-05 1967-03-28 Du Pont Nitramine, nitrocellulose explosive with ester plasticizer
US3338764A (en) * 1965-08-19 1967-08-29 Du Pont Flexible detonating compositions containing high explosives and polymeric metallocarboxylates
US3407731A (en) * 1965-08-19 1968-10-29 Du Pont Flexible detonating fuse
US3449179A (en) * 1966-09-07 1969-06-10 Asahi Chemical Ind Flexible explosive compositions containing block copolymers
US3496870A (en) * 1967-05-23 1970-02-24 Us Navy Spiral burning propellant charge
US3976522A (en) * 1971-07-26 1976-08-24 The United States Of America As Represented By The Secretary Of The Navy Nitroplasticized amine perchlorate flexible explosives
US3959042A (en) * 1973-11-21 1976-05-25 The United States Of America As Represented By The Secretary Of The Navy High impetus, low flame temperature, composite propellants and method of making
US5080735A (en) * 1989-03-03 1992-01-14 E. I. Du Pont De Nemours And Company Low flammability cap-sensitive flexible explosive composition
FR2723086A1 (fr) * 1994-07-29 1996-02-02 Poudres & Explosifs Ste Nale Procede continu de fabrication sans solvant de produits pyrotechniques composites
US5596232A (en) * 1994-07-29 1997-01-21 Societe Nationale Des Poudres Et Explosifs Continuous process for the solventless manufacture of composite pyrotechnic products
WO2016079453A1 (fr) * 2014-11-21 2016-05-26 Herakles Produits explosifs composites de faible epaisseur et leur preparation
FR3028852A1 (fr) * 2014-11-21 2016-05-27 Herakles Produits explosifs composites de faible epaisseur et leur preparation

Also Published As

Publication number Publication date
CH466777A (de) 1968-12-15
GB1082641A (en) 1967-09-06
BE645178A (en)van) 1964-07-01
NL142140B (nl) 1974-05-15
NL6402713A (en)van) 1964-09-15
SE353895B (en)van) 1973-02-19

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