US3228815A - Doublexbase p propellants - Google Patents
Doublexbase p propellants Download PDFInfo
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- US3228815A US3228815A US3228815DA US3228815A US 3228815 A US3228815 A US 3228815A US 3228815D A US3228815D A US 3228815DA US 3228815 A US3228815 A US 3228815A
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- lead
- propellants
- burning rate
- burning
- ultraviolet light
- Prior art date
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- 239000003380 propellant Substances 0.000 title claims description 72
- 239000000203 mixture Substances 0.000 claims description 54
- 239000003607 modifier Substances 0.000 claims description 18
- CNVULGHYDPMIHD-UHFFFAOYSA-L bis[(2-hydroxybenzoyl)oxy]lead Chemical compound [Pb+2].OC1=CC=CC=C1C([O-])=O.OC1=CC=CC=C1C([O-])=O CNVULGHYDPMIHD-UHFFFAOYSA-L 0.000 claims description 12
- 229920001220 nitrocellulos Polymers 0.000 claims description 12
- SNIOPGDIGTZGOP-UHFFFAOYSA-N 1,2,3-propanetrioltrinitrate Chemical compound [O-][N+](=O)OCC(O[N+]([O-])=O)CO[N+]([O-])=O SNIOPGDIGTZGOP-UHFFFAOYSA-N 0.000 claims description 10
- 239000000006 Nitroglycerin Substances 0.000 claims description 10
- 229940014995 Nitroglycerin Drugs 0.000 claims description 10
- 229960003711 glyceryl trinitrate Drugs 0.000 claims description 10
- 239000000020 Nitrocellulose Substances 0.000 claims description 8
- LLVFMJQPUWTQTM-UHFFFAOYSA-M 2-carboxy-5-hydroxyphenolate;lead(2+) Chemical compound [Pb+2].OC1=CC=C(C([O-])=O)C(O)=C1 LLVFMJQPUWTQTM-UHFFFAOYSA-M 0.000 claims description 6
- QBENASORNMPSRU-UHFFFAOYSA-N 2-ethylhexanoic acid;lead(2+) Chemical compound [Pb+2].CCCCC(CC)C(O)=O QBENASORNMPSRU-UHFFFAOYSA-N 0.000 claims description 4
- RWCCWEUUXYIKHB-UHFFFAOYSA-N Benzophenone Chemical compound C=1C=CC=CC=1C(=O)C1=CC=CC=C1 RWCCWEUUXYIKHB-UHFFFAOYSA-N 0.000 claims description 4
- 229940068372 Acetyl salicylate Drugs 0.000 claims 2
- BSYNRYMUTXBXSQ-UHFFFAOYSA-N aspirin Chemical compound CC(=O)OC1=CC=CC=C1C(O)=O BSYNRYMUTXBXSQ-UHFFFAOYSA-N 0.000 claims 2
- 239000006096 absorbing agent Substances 0.000 description 28
- 239000006097 ultraviolet radiation absorber Substances 0.000 description 18
- RUKISNQKOIKZGT-UHFFFAOYSA-N 2-Nitrodiphenylamine Chemical group [O-][N+](=O)C1=CC=CC=C1NC1=CC=CC=C1 RUKISNQKOIKZGT-UHFFFAOYSA-N 0.000 description 14
- 239000000654 additive Substances 0.000 description 12
- 150000008366 benzophenones Chemical class 0.000 description 12
- 238000009472 formulation Methods 0.000 description 12
- 150000003839 salts Chemical class 0.000 description 12
- 239000011780 sodium chloride Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- 239000004449 solid propellant Substances 0.000 description 10
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 8
- 125000003545 alkoxy group Chemical group 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000004014 plasticizer Substances 0.000 description 6
- 239000003381 stabilizer Substances 0.000 description 6
- FIAHSBPKJFNWDB-UHFFFAOYSA-N (6,6-dihydroxy-4,4-dimethoxycyclohex-2-en-1-yl)-phenylmethanone Chemical compound C1=CC(OC)(OC)CC(O)(O)C1C(=O)C1=CC=CC=C1 FIAHSBPKJFNWDB-UHFFFAOYSA-N 0.000 description 4
- FLKPEMZONWLCSK-UHFFFAOYSA-N Diethyl phthalate Chemical compound CCOC(=O)C1=CC=CC=C1C(=O)OCC FLKPEMZONWLCSK-UHFFFAOYSA-N 0.000 description 4
- 230000000996 additive Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000004880 explosion Methods 0.000 description 4
- 239000002360 explosive Substances 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- YGSDEFSMJLZEOE-UHFFFAOYSA-M salicylate Chemical compound OC1=CC=CC=C1C([O-])=O YGSDEFSMJLZEOE-UHFFFAOYSA-M 0.000 description 4
- 229960001860 salicylate Drugs 0.000 description 4
- APNOOECCLHIHKN-UHFFFAOYSA-N (4-hydroxyphenyl)-(4,6,6-trihydroxycyclohexa-2,4-dien-1-yl)methanone Chemical compound C1=CC(O)=CC(O)(O)C1C(=O)C1=CC=C(O)C=C1 APNOOECCLHIHKN-UHFFFAOYSA-N 0.000 description 2
- ZXDDPOHVAMWLBH-UHFFFAOYSA-N 2,4-Dihydroxybenzophenone Chemical compound OC1=CC(O)=CC=C1C(=O)C1=CC=CC=C1 ZXDDPOHVAMWLBH-UHFFFAOYSA-N 0.000 description 2
- JHDYSXXPQIFFJZ-UHFFFAOYSA-M C1(=CC=CC=C1)N=NC1=CC=C(C(C(=O)[O-])=C1)O Chemical compound C1(=CC=CC=C1)N=NC1=CC=C(C(C(=O)[O-])=C1)O JHDYSXXPQIFFJZ-UHFFFAOYSA-M 0.000 description 2
- 229940073532 Candelilla Wax Drugs 0.000 description 2
- 229940014772 DIMETHYL SEBACATE Drugs 0.000 description 2
- DOIRQSBPFJWKBE-UHFFFAOYSA-N Dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 description 2
- 229910001111 Fine metal Inorganic materials 0.000 description 2
- IUJAMGNYPWYUPM-UHFFFAOYSA-N Hentriacontane Chemical compound CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC IUJAMGNYPWYUPM-UHFFFAOYSA-N 0.000 description 2
- 235000015842 Hesperis Nutrition 0.000 description 2
- 235000012633 Iberis amara Nutrition 0.000 description 2
- 240000004804 Iberis amara Species 0.000 description 2
- -1 Nitroglycerin Diethyl phthalate Lead salicylate Chemical compound 0.000 description 2
- MIQLXNMBHDABHZ-UHFFFAOYSA-N OC1(C(C(=O)C2=CC=CC=C2)C=CC(C1)(OC)OC)O.OC1(C(C(=O)C2=CC=CC=C2)C=CC(C1)(O)O)O Chemical compound OC1(C(C(=O)C2=CC=CC=C2)C=CC(C1)(OC)OC)O.OC1(C(C(=O)C2=CC=CC=C2)C=CC(C1)(O)O)O MIQLXNMBHDABHZ-UHFFFAOYSA-N 0.000 description 2
- 241000700159 Rattus Species 0.000 description 2
- 235000002912 Salvia officinalis Nutrition 0.000 description 2
- WLLYXWPCFQAVCZ-UHFFFAOYSA-N [N+](=O)([O-])C(C#N)[N+](=O)[O-].[K] Chemical compound [N+](=O)([O-])C(C#N)[N+](=O)[O-].[K] WLLYXWPCFQAVCZ-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 239000004204 candelilla wax Substances 0.000 description 2
- 235000013868 candelilla wax Nutrition 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 229910052803 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- 230000003247 decreasing Effects 0.000 description 2
- ALOUNLDAKADEEB-UHFFFAOYSA-N dimethyl decanedioate Chemical compound COC(=O)CCCCCCCCC(=O)OC ALOUNLDAKADEEB-UHFFFAOYSA-N 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 230000001747 exhibiting Effects 0.000 description 2
- ZRALSGWEFCBTJO-UHFFFAOYSA-O guanidinium Chemical compound NC(N)=[NH2+] ZRALSGWEFCBTJO-UHFFFAOYSA-O 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 125000004435 hydrogen atoms Chemical class [H]* 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 238000009114 investigational therapy Methods 0.000 description 2
- 150000002611 lead compounds Chemical class 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006011 modification reaction Methods 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- 238000006552 photochemical reaction Methods 0.000 description 2
- 230000000750 progressive Effects 0.000 description 2
- 235000002020 sage Nutrition 0.000 description 2
- 239000001296 salvia officinalis l. Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 239000001993 wax Substances 0.000 description 2
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B25/00—Compositions containing a nitrated organic compound
- C06B25/18—Compositions containing a nitrated organic compound the compound being nitrocellulose present as 10% or more by weight of the total composition
- C06B25/24—Compositions containing a nitrated organic compound the compound being nitrocellulose present as 10% or more by weight of the total composition with nitroglycerine
- C06B25/26—Compositions containing a nitrated organic compound the compound being nitrocellulose present as 10% or more by weight of the total composition with nitroglycerine with an organic non-explosive or an organic non-thermic component
Definitions
- This invention relates to a method for increasing the burning rate of nitrocellulose-base propellants, and to new nitrocellulose-base propellent formulations having improved burning rates.
- the relationship is particularly important in the zone of useful rocket pressures.
- a plot of Log r against Log p for conventional type propellants, for example, produces a straight line of slope n, that is, there is a progressive increase in burning rate for each increase in pressure.
- the pressure exponent becomes zero in a certain useful region of pressure.
- the burning rate of some solid propellants can be increased by increasing their calorific value (heat of explosion).
- heat of explosion heat of explosion
- mesa or plateau-type propellants the beneficial effects of the ballistic modifiers which produce the mesas and plateaus are gradually lost or dissipated as the heat of explosion increases; in other words there are limits beyond which the usual metal salt modifiers cannot be satisfactorily employed.
- 3,228,815 Patented Jan. 11, 1966 burning rate of double-base propellants can also be increased by adding burning rate accelerators such as guanidinium S-nitroaminotetrazole, nitroarninoguanidine, S-aminotetrazole, potassium dinitroacetonitrile, certain coordination compounds of cobalt, etc.
- burning rate accelerators such as guanidinium S-nitroaminotetrazole, nitroarninoguanidine, S-aminotetrazole, potassium dinitroacetonitrile, certain coordination compounds of cobalt, etc.
- These accelerators are normally used at concentrations ranging from 5 to 50 percent. Because these compounds are insoluble in the propellant matrix and cause an opaqueness, they vitiate the mesa or plateau in those double-base formulations which normally show this phenomenon. Some of these accelerators also cause propellant instability.
- Burning rates can be increased in some cases by adding certain finely divided metals, such as aluminum, magnesium, boron, etc., but such materials again tend to eliminate the desirable mesa effects if used in quantities needed to get really significant boosts in burning rate.
- Fine metal wires can also be dispersed throughout a double-base propellant to elfect substantial increases in the normal burning rate without, in this case, vitiating the mesa; however, the rate is not increased in the mesa region.
- FIGS. 1-5, inclusive present graphs of pressure-burning rate curves for the N5 propellent formulation used to illustrate this invention and for this formulation modified in various ways, including the addition thereto of ultraviolet light absorbers, to illustrate the effectiveness of ultraviolet light absorbers in producing superrate burning.
- the curves bear example numbers to indicate the examples in the tables to which they correspond.
- the ultraviolet light absorbers used to illustrate the invention are hydroxy and alkoxy substituted benzophenones.
- the percentage composition limits of the double-base propellant, N5, used to illustrate the invention are as follows- Component: Wt. percent Nitrocellulose 4460 Nitroglycerin 28-47 Non-explosive plasticizer 315 Stabilizer 1-5
- Ballistic modifier 2-5 The non-explosive plasticizer may be diethyl phthalate, dibutyl phthalate, dimethyl sebacate or others.
- the stabilizer is 2-nitrodiphenylamine.
- the ballistic modifier may be lead salicylate, lead Z-ethylhexoate, lead acetyl- 3 salicylate, lead 2,4-dihydroxybenzoate and certain other lead salts.
- N-S used in the examples is the following g z g' (126 N percent) 5 ultraviolet light absorber A. Comparison of the curves Nitroglycerin 34.8 of Ex mples IX and with the curves for other exam les Diethyl phthalate 108 hows that the ultraviolet light absorbers produce their zmitrodiphenylamine 20 best effect in the absence of other stab1lizers such as 2- Lead salicylate L2 t o lp enylamlne.
- Examples XI and XII are N-S compositions modified The examples given in the following table are illustraby the substitution for lead salicylate of Pb S-(Z-carboxytive of the invention but not limiting thereof.
- the forphenylazo) salicylate and Pb 5-(phenylazo)salicylate, remulations were made by simply incorporating the ultraspectively, in amounts such that the total lead content violet light absorber in the propellent mix which was of the N5 composition is unchanged.
- Examples XIII made .by a solvent process.
- XIV are the compositions of Examples XI and XII, Table 4.
- Example I being N-S formulation without 2-nitrodiphenylamine
- Example III being the example containing the optimum amount of Ingredient Examples (wt. in grams) VII VIII XIII XV Nitrocellulose Nitroglycerin Diethyl phthalate Lead salicylate. Lead 2-ethylhexoate Lead 5-(2-carboxyphenylazo) salicy Lead 5-(pheny1azo) salicylate- 2-nitrodiphenylamine Candelilla wax U.V.L.
- absorber A 2,tdihydroxybenzophenone 2,2,4,4-tetrahydroxybenzophenone 2,2-dihydroxy-4,4-dimethoxybenzophenone *Mixture of 2,2-dihydroxy-4,4-dimethoxybenzophenone and 2,24,4-tetral1ydr0xybenzophenone.
- FIG. 1 presents the pres- 40 respectively, modified by substituting ultraviolet light absure-burning rate curves for N5 and for compositions of Examples I-V, inclusive.
- Example I which was included for comparative purposes, does not contain any 2-nitrodiphenylamine. It will be noted that the curve presents the characteristic mesa phenomenon but the burning rate is lower than that of N-S.
- Examples II-V, inclusive contain no Z-nitrodiphenylamine but do contain varying amounts up to five percent by weight of the ultraviolet light absorber A which is a mixture of 2,2-dihydroxy-4,4- dimethoxybenzophenone and 2,2,4,4'-tetrahydroxybenzophenone. It will be noted by comparison of these curves with those for N5 that the presence of the ultraviolet light absorber markedly increases the burning rate in the mesa region in all cases, with the exception of Example V, with some shift in the mesa, and that Example III, containing two weight percent of additive, gives the rnost pronounced eliect. Increasing the amount of ultraviolet light absorber to five percent destroys the beneficial mesa ballistics.
- FIG. 2 gives comparative showings of the pressureburning rate curve for N-S and curves of N-S formulation modified by the addition thereto of other ultraviolet light absorbers.
- the curve for Example III, the formulation containing the optimum amount of ultraviolet light absorber A is included for comparative purposes.
- the ultraviolet light absorbers used in Examples VI, VII and VIII of FIG. 2 were 2,4-dihydroxybenzophenone, 2,2,4,4:- tetrahydroxybenzophenone and 2,2'-dihydroxy-4,4'-d1- methoxybenzophenone, respectively. It will be noted that in all cases a significant increase in burning rate in the mesa region was achieved over the burning rate of unmodified N-S.
- FIG. 3 presents the pressure-burning rate curves for Examples IX and X containing two grams each of both 2-nitrodiphenylamine and an ultraviolet absorber.
- sorber A in equal amount for 2-nitrodiphenylamine. It will be noted that a Well defined increase in burning rate is obtained by addition of the ultraviolet light absorber A. The four examples show that ultraviolet light absorber A is effective when used in combination with lead salts other than lead salicylate.
- FIG. 5 presents curves for N5 propellant, N5 propellant with the Z-nitrodiphenylamine removed (Example I), and for N5 composition with both 2-nitrodiphenylamine and the lead salts removed (Example XV).
- EX- ample XV contained about two weight percent of ultraviolet light absorber A.
- the graph illustrates that when both the stabilizer (2-nitrodiphenylamine) and the ballistic modifiers (lead salicylate and lead Z-ethylhexoate) are omitted from the basic N-5 formulation, super-rate burning is completely lost. When only the 2-nitrodi- .phenylamine is removed the super-rate burning is both decreased and shifted to lower pressures.
- the graph clearly indicates that the ultraviolet light absorbers are not by themselves ballistic modifiers; they only influence, perhaps synergistically, the behavior of the lead salts.
- the invention is not limited in application to propellants containing nitroglycerin as certain other polynitrate esters may be employed as the high energy plasticizer. Neither is it limited to the particular double-base propellant, N-S, used to illustrate it, as it is effective with other double-base mesa or plateau type propellants.
- Propellant formulations comprising from about 44- 60 percent nitrocellulose; from about 2847 percent nitroglycerin; from about 2-5 percent of ballistic modifier selected from the class consisting of lead salicylate, lead 2-ethy1hexoate, lead aoetylsalicylate, lead 2,4-dihydroxybenzoate, and mixtures thereof; and from about 1-5 percent of a benzophenone having the formula OH R wherein R represents a member from the group consisting of lower alkoxy and hydroxyl, R is a member from the group consisting of hydrogen, hydroxyl, and lower References Cited by the Examiner UNITED STATES PATENTS 2,440,327 4/ 1948 Crawford. 2,574,479 11/1951 Hickman. 2,628,561 2/1953 Sage et al 520.5 X
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Description
Jan. 11, 1966 H Y ETAL 3,228,815
F INCREASED BURNING RATE DOUBLE-BASE PROPELLANTS O CONTAINING BENZOPHENONES 5 Sheets-Sheet 1 Filed Oct. 21, 1957 5a wmzwwmmm O O O O O O O O O O m w m a 6 nN O nun O \H MAE! Om O BURNING RATE, lN/SEC Jan. 11, 1966 DOUBLE-BASE PROPELLANTS OF INCREASED BURNING RATE Filed 001;. 21, 1957 R. A. HENRY ET AL 3,228,815
CONTAINING BENZOPHENONES 5 Sheets-Sheet 2 PSI EXAMPLE I EXAMPLE IlI PRESSURE,
EXAMPLE 1::
EXAMPLE c o o r- BURNING o "I o lN SEC RAT INVENTORS RONALD A. HENRY WILLIAM S. MC EWAN ATTORNEYS Jan. 11, 1966 HENRY ET AL 3,228,815
DOUBLE-BASE PROPiEILLANTS OF INCREASED BURNING RATE CONTAINING BENZOPHENONES Filed OGt. 21. 1957 5 Sheets-Sheet 4 -EXAMPLE I] -4% EXAMPLE XII//// PRESSURE,
EXAMPLE nI EXAMPLE EXAMPLE XII BURNING RATE lN/SEC INVENTORS RONALD A. HENRY WILLiAM 8. MC EWAN BY AWL ATTORNEYS Jan. 11, 1966 R. A. HENRY ETAL DOUBLE-BASE PROPELLANTS OF INCREASED BURNING RATE CONTAINING BENZOPHENONES Flled Oct. 21, 1957 5 Sheets-Sheet 5 an wmowmwmn 0 o 0 0 o a m m m m m HM m az xwv\ 4 5256 ON O Om O
Om O
BURNING RATE, lN/SEC United States Patent 6 T 3,228,815 BASE PROPELLANTS F INCREASED BURNING RATE CONTAINING BENZOPHENONES Ronald A. Henry and William S. McEwan, China Lake, Calili, assignors to the United States of America as represented by the Secretary of the Navy Filed Oct. 21, 1957, Ser. No. 691,521 4 Claims. (Cl. 149-98) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
This invention relates to a method for increasing the burning rate of nitrocellulose-base propellants, and to new nitrocellulose-base propellent formulations having improved burning rates.
A great deal of research is being directed toward increasing the burning rate of solid propellants for rockets 'in the zone of useful rocket pressures, roughly, between 7003,000 p.s.i. Faster burning rates are important in the interest of increased thrust and thereby increased range of the rocket without added weight of propellant.
Various additives have been used in the past to increase the burning rate of solid propellants. The difiiculty in finding suitable additives for this purpose is due to the fact that the additive must not prohibitively affect such critical properties of the propellant as stability, calorific value, and ballistic characteristics. The relatively recently developed plateau and mesa type propellants are examples of propellants possessing ballistic properties which are highly sensitive to the addition of even small amounts of additives. These latter propellants are characterized by an unusual pressure-burning rate relationship, this relationship defining the plateau and mesa characteristics. The pressure burning rate relationship is defined by the slope n, or pressure exponent, of the curve produced by a logarithmic graph of the burning rate of propellant plotted against pressure. The relationship is particularly important in the zone of useful rocket pressures. The relationship between the pressure at which a propellant burns and its burning rate is mathematically expressed as r cp or as Log r=n Log p+log c, where r is the burning rate, p is the pressure at which the burning rate is measured and c and n are constants characteristic of a given propellant. A plot of Log r against Log p for conventional type propellants, for example, produces a straight line of slope n, that is, there is a progressive increase in burning rate for each increase in pressure. However, in the case of plateau type propellants the pressure exponent becomes zero in a certain useful region of pressure. In the case of the mesa type propellant the pressure exponent becomes zero at some point and then reaches a negative value thereafter in the region of useful rocket pressures so that the burning rate in this negative slope region actually decreases with increase in pressure. The plateau and mesa phenomena are due to the presence of critical amounts of certain lead compound modifiers, the phenomena being extremely sensitive to the addition of foreign substances to the propellant composition. There are a number of now well known advantages to propellants exhibiting the above phenomena.
The burning rate of some solid propellants can be increased by increasing their calorific value (heat of explosion). However, with mesa or plateau-type propellants the beneficial effects of the ballistic modifiers which produce the mesas and plateaus are gradually lost or dissipated as the heat of explosion increases; in other words there are limits beyond which the usual metal salt modifiers cannot be satisfactorily employed. The
3,228,815 Patented Jan. 11, 1966 burning rate of double-base propellants can also be increased by adding burning rate accelerators such as guanidinium S-nitroaminotetrazole, nitroarninoguanidine, S-aminotetrazole, potassium dinitroacetonitrile, certain coordination compounds of cobalt, etc. These accelerators are normally used at concentrations ranging from 5 to 50 percent. Because these compounds are insoluble in the propellant matrix and cause an opaqueness, they vitiate the mesa or plateau in those double-base formulations which normally show this phenomenon. Some of these accelerators also cause propellant instability. Burning rates can be increased in some cases by adding certain finely divided metals, such as aluminum, magnesium, boron, etc., but such materials again tend to eliminate the desirable mesa effects if used in quantities needed to get really significant boosts in burning rate. Fine metal wires can also be dispersed throughout a double-base propellant to elfect substantial increases in the normal burning rate without, in this case, vitiating the mesa; however, the rate is not increased in the mesa region.
It is an object of this invention to provide a method for increasing the burning rate of solid propellants without prohibitively altering other required characteristics of the propellants.
It is another object of this invention to provide improved propellent compositions containing additives which increase their burning rates and do not prohibitively affect other required properties of the propellants.
The above objects have been accomplished by incorporating into conventional solid propellent formulations up to about five percent of certain propellant-soluble ultraviolet light absorbers.
The invention is best understood by reference to the following description taken together with the accompanying drawings in which:
FIGS. 1-5, inclusive, present graphs of pressure-burning rate curves for the N5 propellent formulation used to illustrate this invention and for this formulation modified in various ways, including the addition thereto of ultraviolet light absorbers, to illustrate the effectiveness of ultraviolet light absorbers in producing superrate burning. The curves bear example numbers to indicate the examples in the tables to which they correspond.
During an investigation to ascertain the mechanism by which certain lead salts produced super-rate burning in mesa or plateau-type double-base propellants, it was discovered that light or radiant energy played an important role in the reactions leading to super-rate burning. Furthermore, this photochemical reaction was found to occur in the depths of the solid propellant, below the decomposing and burning surface. This discovery lead to the prediction that the addition of small amounts of propellant-soluble, organic compounds which strongly absorb ultraviolet light would markedly influence the reactions leading to super-rate burning.
The ultraviolet light absorbers used to illustrate the invention are hydroxy and alkoxy substituted benzophenones. The percentage composition limits of the double-base propellant, N5, used to illustrate the invention are as follows- Component: Wt. percent Nitrocellulose 4460 Nitroglycerin 28-47 Non-explosive plasticizer 315 Stabilizer 1-5 Ballistic modifier 2-5 The non-explosive plasticizer may be diethyl phthalate, dibutyl phthalate, dimethyl sebacate or others. The stabilizer is 2-nitrodiphenylamine. The ballistic modifier may be lead salicylate, lead Z-ethylhexoate, lead acetyl- 3 salicylate, lead 2,4-dihydroxybenzoate and certain other lead salts. The actual composition of N-S used in the examples is the following g z g' (126 N percent) 5 ultraviolet light absorber A. Comparison of the curves Nitroglycerin 34.8 of Ex mples IX and with the curves for other exam les Diethyl phthalate 108 hows that the ultraviolet light absorbers produce their zmitrodiphenylamine 20 best effect in the absence of other stab1lizers such as 2- Lead salicylate L2 t o lp enylamlne. These two examples also illustrate Lead 2 ethy1hexoate L2 he r uced elfect resulting from an excess of ultraviolet Candelma Wax 2 light absorbers, 2-mtrod1phenylam1ne itself being an ultraviolet light absorber. The N-5 propellant is presently being used in large FIG. 4 presents the pressure-burning rate curves for quantities by the Armed Forces in the 2.75-inch folding x pl XPXIV, inclusive- T e Curv s for N-S and fin aircraft rocket known as the Mighty Mouse," and Example III'are also presented for comparative purposes. which is disclosed in US. Patent No. 2,801,587. Examples XI and XII are N-S compositions modified The examples given in the following table are illustraby the substitution for lead salicylate of Pb S-(Z-carboxytive of the invention but not limiting thereof. The forphenylazo) salicylate and Pb 5-(phenylazo)salicylate, remulations were made by simply incorporating the ultraspectively, in amounts such that the total lead content violet light absorber in the propellent mix which was of the N5 composition is unchanged. Examples XIII made .by a solvent process. and XIV are the compositions of Examples XI and XII, Table 4. curves for Examples I and III and for N-5 are included for comparative purposes, Example I being N-S formulation without 2-nitrodiphenylamine and Example III being the example containing the optimum amount of Ingredient Examples (wt. in grams) VII VIII XIII XV Nitrocellulose Nitroglycerin Diethyl phthalate Lead salicylate. Lead 2-ethylhexoate Lead 5-(2-carboxyphenylazo) salicy Lead 5-(pheny1azo) salicylate- 2-nitrodiphenylamine Candelilla wax U.V.L. absorber A* 2, tdihydroxybenzophenone 2,2,4,4-tetrahydroxybenzophenone 2,2-dihydroxy-4,4-dimethoxybenzophenone *Mixture of 2,2-dihydroxy-4,4-dimethoxybenzophenone and 2,24,4-tetral1ydr0xybenzophenone. Reference is made to FIG. 1 which presents the pres- 40 respectively, modified by substituting ultraviolet light absure-burning rate curves for N5 and for compositions of Examples I-V, inclusive. Example I, which was included for comparative purposes, does not contain any 2-nitrodiphenylamine. It will be noted that the curve presents the characteristic mesa phenomenon but the burning rate is lower than that of N-S. Examples II-V, inclusive, contain no Z-nitrodiphenylamine but do contain varying amounts up to five percent by weight of the ultraviolet light absorber A which is a mixture of 2,2-dihydroxy-4,4- dimethoxybenzophenone and 2,2,4,4'-tetrahydroxybenzophenone. It will be noted by comparison of these curves with those for N5 that the presence of the ultraviolet light absorber markedly increases the burning rate in the mesa region in all cases, with the exception of Example V, with some shift in the mesa, and that Example III, containing two weight percent of additive, gives the rnost pronounced eliect. Increasing the amount of ultraviolet light absorber to five percent destroys the beneficial mesa ballistics.
FIG. 2 gives comparative showings of the pressureburning rate curve for N-S and curves of N-S formulation modified by the addition thereto of other ultraviolet light absorbers. The curve for Example III, the formulation containing the optimum amount of ultraviolet light absorber A is included for comparative purposes. The ultraviolet light absorbers used in Examples VI, VII and VIII of FIG. 2 were 2,4-dihydroxybenzophenone, 2,2,4,4:- tetrahydroxybenzophenone and 2,2'-dihydroxy-4,4'-d1- methoxybenzophenone, respectively. It will be noted that in all cases a significant increase in burning rate in the mesa region was achieved over the burning rate of unmodified N-S.
FIG. 3 presents the pressure-burning rate curves for Examples IX and X containing two grams each of both 2-nitrodiphenylamine and an ultraviolet absorber. The
sorber A in equal amount for 2-nitrodiphenylamine. It will be noted that a Well defined increase in burning rate is obtained by addition of the ultraviolet light absorber A. The four examples show that ultraviolet light absorber A is effective when used in combination with lead salts other than lead salicylate.
FIG. 5 presents curves for N5 propellant, N5 propellant with the Z-nitrodiphenylamine removed (Example I), and for N5 composition with both 2-nitrodiphenylamine and the lead salts removed (Example XV). EX- ample XV contained about two weight percent of ultraviolet light absorber A. The graph illustrates that when both the stabilizer (2-nitrodiphenylamine) and the ballistic modifiers (lead salicylate and lead Z-ethylhexoate) are omitted from the basic N-5 formulation, super-rate burning is completely lost. When only the 2-nitrodi- .phenylamine is removed the super-rate burning is both decreased and shifted to lower pressures. The graph clearly indicates that the ultraviolet light absorbers are not by themselves ballistic modifiers; they only influence, perhaps synergistically, the behavior of the lead salts.
Taliani stability tests indicated that all of the formulations containing rate booster additions are sufficiently stable for use as propellants.
While the invention has been illustrated by the use of specific ultraviolet light absorbers, the hydroxy and alkoxy substituted benzophenones, it is not limited to the use of these compounds, as other ultraviolet light absorbers may be used.
The invention is not limited in application to propellants containing nitroglycerin as certain other polynitrate esters may be employed as the high energy plasticizer. Neither is it limited to the particular double-base propellant, N-S, used to illustrate it, as it is effective with other double-base mesa or plateau type propellants.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed is:
1. Propellant formulations comprising from about 44- 60 percent nitrocellulose; from about 2847 percent nitroglycerin; from about 2-5 percent of ballistic modifier selected from the class consisting of lead salicylate, lead 2-ethy1hexoate, lead aoetylsalicylate, lead 2,4-dihydroxybenzoate, and mixtures thereof; and from about 1-5 percent of a benzophenone having the formula OH R wherein R represents a member from the group consisting of lower alkoxy and hydroxyl, R is a member from the group consisting of hydrogen, hydroxyl, and lower References Cited by the Examiner UNITED STATES PATENTS 2,440,327 4/ 1948 Crawford. 2,574,479 11/1951 Hickman. 2,628,561 2/1953 Sage et al 520.5 X
FOREIGN PATENTS 485,662 8/1952 Canada.
LEON D. ROSDOL, Primary Examiner.
20 B. R. PADGETT. Assistant Examiner.
Claims (1)
1. PROPELLANT FORMULATIONS COMPRISING FROM ABOUT 4460 PERCENT NITROCELLULOSE; FROM ABOUT 28-47 PERCENT NITROGLYCERIN; FROM ABOUT 2-5 PERCENT OF BALLISTIC MODIFIER SELECTED FROM THE CLASS CONSISTING OF LEAD SALICYLATE, LEAD 2-ETHYLHEXOATE, LEAD ACETYLSALICYLATE, LEAD 2,4-DIHYDROXYBENZOATE, AND MIXTURES THEREOF; AND FROM ABOUT 1-5 PERCENT OF A BENZOPHENONE HAVING THE FORMULA
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US3228815A true US3228815A (en) | 1966-01-11 |
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US3228815D Expired - Lifetime US3228815A (en) | Doublexbase p propellants |
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Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3712223A (en) * | 1970-10-07 | 1973-01-23 | R Degn | Pyrotechnic, whistle, and method of making |
US3793098A (en) * | 1971-12-27 | 1974-02-19 | Nippon Oils & Fats Co Ltd | Composite double base propellant with {62 -diketone stabilizer |
US3860462A (en) * | 1970-02-09 | 1975-01-14 | Us Army | Propellant composition of the nitrocellulose type containing non lead-containing ballistic modifiers |
US3954533A (en) * | 1969-10-29 | 1976-05-04 | The United States Of America As Represented By The Secretary Of The Navy | High pressure-burning propellant composition |
US3994757A (en) * | 1971-05-04 | 1976-11-30 | The United States Of America As Represented By The Secretary Of The Army | Ballistic modifier resistant to hydrolysis |
US4202714A (en) * | 1970-09-11 | 1980-05-13 | The United States Of America As Represented By The Secretary Of The Army | Ballistic modifiers and synthesis of the ballistic modifiers |
US4243444A (en) * | 1970-09-11 | 1981-01-06 | The United States Of America As Represented By The Secretary Of The Army | Ballistic modifiers, synthesis . . . propellants |
US4298411A (en) * | 1969-07-14 | 1981-11-03 | Hercules Incorporated | Crosslinked smokeless propellants |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2440327A (en) * | 1943-12-29 | 1948-04-27 | Univ Minnesota | "hot" double-base powder |
US2574479A (en) * | 1943-01-30 | 1951-11-13 | Clarence N Hickman | Propellant having an opacifier for preventing self-ignition by radiant energy radiations |
CA485662A (en) * | 1952-08-12 | W. Cairns Robert | Smokeless powder | |
US2628561A (en) * | 1943-03-17 | 1953-02-17 | Bruce H Sage | Propellant powder grain for rocket motors |
-
0
- US US3228815D patent/US3228815A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA485662A (en) * | 1952-08-12 | W. Cairns Robert | Smokeless powder | |
US2574479A (en) * | 1943-01-30 | 1951-11-13 | Clarence N Hickman | Propellant having an opacifier for preventing self-ignition by radiant energy radiations |
US2628561A (en) * | 1943-03-17 | 1953-02-17 | Bruce H Sage | Propellant powder grain for rocket motors |
US2440327A (en) * | 1943-12-29 | 1948-04-27 | Univ Minnesota | "hot" double-base powder |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4298411A (en) * | 1969-07-14 | 1981-11-03 | Hercules Incorporated | Crosslinked smokeless propellants |
US3954533A (en) * | 1969-10-29 | 1976-05-04 | The United States Of America As Represented By The Secretary Of The Navy | High pressure-burning propellant composition |
US3860462A (en) * | 1970-02-09 | 1975-01-14 | Us Army | Propellant composition of the nitrocellulose type containing non lead-containing ballistic modifiers |
US4202714A (en) * | 1970-09-11 | 1980-05-13 | The United States Of America As Represented By The Secretary Of The Army | Ballistic modifiers and synthesis of the ballistic modifiers |
US4243444A (en) * | 1970-09-11 | 1981-01-06 | The United States Of America As Represented By The Secretary Of The Army | Ballistic modifiers, synthesis . . . propellants |
US3712223A (en) * | 1970-10-07 | 1973-01-23 | R Degn | Pyrotechnic, whistle, and method of making |
US3994757A (en) * | 1971-05-04 | 1976-11-30 | The United States Of America As Represented By The Secretary Of The Army | Ballistic modifier resistant to hydrolysis |
US3793098A (en) * | 1971-12-27 | 1974-02-19 | Nippon Oils & Fats Co Ltd | Composite double base propellant with {62 -diketone stabilizer |
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