FR2526418A1 - PROPULSIVE COMPOSITION CONTAINING NITROCELLULOSE, NITROGLYCERIN, COPPER BENZOATE AND LEAD OR ITS DERIVATIVES, IN PARTICULAR FOR SPRAY - Google Patents

Abstract

PROPULSIVE COMPOSITION; IT CONTAINS COPPER BENZOATE AND AT LEAST ONE CONSTITUENT CHOSEN FROM ORGANIC LEAD SALTS, METAL LEAD AND MINERAL LEAD COMPOUNDS AS A COMBUSTION CATALYST; THE PROPULSIVE COMPOSITION HAS A LOW PRESSURE EXHIBITOR AND CAN BE USED AS A SPECIFIC HIGH PULSE PROPERGOL.

Description

The present invention relates to a composition

  In particular, the invention relates to a composition

  propulsive composition having a low pressure exponent and especially propulsive compositions with high specific impulse and low pressure exponent. To date, a double base propellant has been used

  (hereinafter referred to as propergol DB) consisting mainly of nitro-

  cellulose (hereinafter abbreviated as NC) and nitro-

  glycerin (hereinafter abbreviated to NG) in the field

  Smokeless propellants for rockets.

  Recently, high impulse propellants have been developed which correspond to the high performance of rocket propellants, that is, a modified dual-base composite propellant (hereinafter referred to as "propellant") has been developed. after the abbreviation propellant CMDB) containing the main components NC and NG previously described, and, in addition, oxidants

  such as ammonium perchlorate (hereinafter abbreviated

  AP), cyclotrimethylenetrinitramine (hereinafter abbreviated as RDX) and metal powders such as aluminum powders and the like; In addition, a

  composite propellant with a double base (hereinafter abbreviated

  propellant composition CBD) obtained by addition of a propellant binder DB

or propellant CMDB.

  It is known that the relation between the combustion rate and the combustion pressure of these propellants is generally represented by the following formula nr = ap in which r represents the combustion rate, p represents the combustion pressure, N represents the exponent of pressure and

  a represents a constant specific to the individual propellant.

  In a rocket propellant, it is generally desirable from the point of view of the design of the rocket motor and the stability of the combustion of the propellant itself, that the previously indicated pressure presenter N is low. N is almost equal to zero (n 0 O), the combustion is in plateau and when N is less than zero (n <0), the combustion is in mesa These combustion properties

  in plateau and mesa are the preferable properties of a proper

gol for rockets.

  It is known that, as a combustion catalyst capable of imparting these preferable properties to a DB propellant, an organic lead salt, such as planar salicylate, the

  lead stearate or the like, lead oxide or lead

  liquefaction, alone or in admixture with a copper compound, such as an organic copper salt, for example copper salicylate and copper stearate, or a copper oxide or metallic copper

  (published Japanese Patent Application No. 4,928 / 74).

  Such a common combustion catalyst makes it possible to

  to confer the characteristics described above on

  gols DB having a high content of NC and releasing a quantity

  relatively low energy However, the catalyst of com-

  is inefficient or ineffective in reducing the N-pressure exponent in a DB propellant having a high NG content and in high-impulse propellants, such as

  CMDB propellants and CBD propellants previously described.

  Recently, we have been looking for catalysts

  which can significantly reduce the exponent of

  such high-impulse propellants and

  have conducted various studies and discovered that a new combustion catalyst consisting of a particular organic copper salt and at least one constituent selected from organic lead salts, metallic lead and lead inorganic compounds, satisfies need previously indicated and the invention

follows from this discovery.

  The propulsive composition of the invention which

  is at least NC and NG is characterized in that it further contains as a combustion catalyst copper benzene and at least one constituent selected from the organic salts of lead,

  metallic lead and lead inorganic compounds.

  Other features and advantages of the invention

  tion will be better understood by reading the description that will

  follow several embodiments and with reference to the accompanying drawings in which: Figures 1 to 3 are graphs illustrating

  the relation between the combustion pressure and the speed of com-

  DB propellant combustion; and Figures 4 and 5 are graphs illustrating

  the relation between the combustion pressure and the speed of com-

  respectively a propellant CMDB and a propellant CDB.

  The preferred embodiment of the invention will now be described. The combustion catalyst used in the invention consists of copper benzoate and at least one constituent selected from the organic salts of lead, metallic lead. and lead inorganic compounds As lead organic salts, lead salicylate, lead stearate, lead resorcylate and lead 2-ethyl hexanoate and the like may be used as the inorganic compounds of lead. lead stannate, lead oxide and the like and one can also

  use of metallic lead Copper benzoate is used in

  pairing with at least one constituent selected from these organic salts

  lead, lead and these lead inorganic compounds.

  The combustion catalyst is preferably employed in an amount of from 0.5 to 5% by weight, based on the total amount of the propellent composition. The amount of copper benzoate is preferably 0.2 to 4% by weight. in

  weight relative to the total amount of the propellant composition.

  When the amount of lead benzoate contained in a

  propellant is less than 0.2% by weight and that the amount of the constituent selected from organic lead compounds, metallic lead and lead inorganics is

  less than 0.3% by weight, the propellant composition has an expo-

  When the amount of copper benzoate exceeds 4% by weight and the total amount of the combustion catalyst exceeds 5% by weight, the amount of combustion catalyst with no energetic activity increases. so that the specific impulse of the propulsive composition obtained is low Therefore, it is preferred not to use the catalyst

  in a quantity so small or so high.

  The propellant of the invention containing NC, NG and the combustion catalyst may optionally contain plasticizers such as diethyl phthalate, dioctyl phthalate, tributyl phosphate, triacetin, dioctyl adipate, sebacate. dioctyl and the like; oxidants such as RDX, cyclotetramethylenetetranitramine (HMX), AP, potassium perchlorate and the like; metal powders such as aluminum powders and the like; stabilizers such as diphenylamine and the like; binders such as a polyester to

  isocyanate termination and the like; gelling agents and the like.

  The amounts of these ingredients used can

  generally be determined taking into account the specific impulse

  For example, in a DB propellant with a high specific impulse, the amount of CN used is different from the other properties of combustion, mechanical properties, safety, productivity and aging resistance of the desired propellant composition. at 50 wt%, that of NG 40 & 65% by weight, the total amount of plasticizer and gelling agent is

  3 to 15% by weight and the amount of stabilizer is 0.3 to 57.

  In order to produce the CMDB propellant, 0 to 40 parts by weight of AP are added, 0 to 60 parts by weight of nitramines such as RDX, HMX and the like and 0 to 30 parts by weight of aluminum alone or in part.

  mixture, to 100 parts by weight of the DB propellant having the

  previously described. The CBD propellant was

  0.3 to 10% by weight of the total amount of the plasticizer and the gelling agent described above by a binder. The propellant DB,

  propellant CMDB and the CDB propellant described above must be

  0.5 to 5% by weight of the combustion catalyst of the invention.

  The propulsive composition according to the invention can

  be produced for example as follows.

  NG, a plasticizer and a combustion catalyst are then mixed under reduced pressure. Subsequently, the mixture is optionally mixed with an oxidizing agent and metal powders. In addition, it is optionally mixed with a binder. Next, it is mixed with a stabilizer and a fine powder of NC under reduced pressure

  to obtain a mixture of the homogeneous mixture

  binds in a mold under reduced pressure and the molded article is heated to harden and obtain a propellant DB, a propellant COIDB

or a CDB propellant.

  The invention is illustrated by the following nonlimiting examples In the table, the percentages are expressed

in weight.

Example 1

  A propellant DB is prepared in the following manner

  having the composition of Example 1 indicated in the table below.

  efore. A mixture of 3200 g of NG and 800 g of diethyl phthalate (DEP) is stirred, introduced into a mixer and then mixed at 30 ° C. for 20 minutes under reduced pressure with g of lead salicylate (Pb-Sa). whose average size

  particle size does not exceed 10 μm and 100 g of copper benzoate

  Be) having an average particle size of not more than 10 μm.

  After mixing, 200 g of nitro-2-diphenylamine (2-NDPA) and 500 g of fine-powder NC are added to the mixture obtained above and the mixture is mixed at 40 ° C. for 40 minutes under reduced pressure. the slurry obtained in a mold under reduced pressure and the molded article was cured at 500 ° C. for 10 days to obtain a propellant DB 55 strand-shaped samples were prepared from this propellant DB and subjected to a test on

strands according to the following method.

  Five strand samples were blown at each of the pressures obtained at 10 bar elevations in the range of 30 bar to 130 bar under the nitrogen atmosphere with a Crawford strand tester and the speed was measured. of

  burning samples in strands.

  The results obtained are represented by a continuous line curve in FIG. 1 In FIG. 1, the ordinates represent the logarithm of the combustion rate (r, unit: mn / s) and the abscissae represent the logarithm of

MMMP, "-, -

  the combustion pressure (P, unit: bar) Figure 1 is a graph illustrating the relationship between the combustion pressure

  and the rate of combustion obtained by establishing a

  average combustion rate for each combustion pressure. Comparative Example 1 A DB propellant according to Example 1 is prepared, except that copper salicylate is used instead of copper benzoate. The propellant DB is subjected to the same test as that described in Example 1. results obtained are represented by the

discontinuous curve of Figure 1.

Example 2

  A propellant DB with a high specific impulse is prepared.

  according to example 11, except that the quantities

  NC and NG as shown in Example 2 in the table below.

  after The specific pulse indicated in the table is the value calculated by use of NASA's theoretical calculation program for rocket performance under combustion pressure

of 78.4 bars.

  The propellant obtained is subjected to the same test as that described in Example 1. The results are illustrated by the

continuous curve of FIG.

Comparative Example 2

  A propellant DB with a high specific impulse is prepared.

  According to Example 2, except that copper salicylate is used instead of copper benzoate. The propellant is submitted.

  obtained in the same test as that described in Example 1.

  obtained states are illustrated by the discontinuous curve of Figure 2.

Example 3

  A high specific impulse D-type propellant having the composition indicated for Example 3 in the table is prepared according to Example 1, except that lead oxide (Pb O) is used in Instead of the lead salicylate, the propellant obtained is subjected to the same test as that described in Example 1. The results

  are illustrated by the continuous curve of Figure 3.

Comparative Example 3

  A propellant DB with a high specific impulse is prepared.

  the composition shown for Comparative Example 3 in the table according to Example 3, except that copper salicylate is used instead of copper benzoate.

  propellant obtained in the same test as that described in Example 1.

  The results obtained are illustrated by the discontinuous curve

of Figure 3.

Example 4

  A CMDB propellant is prepared as follows

  having the composition shown for Example 4 in the table.

  A mixture of 3920 g of NG and 640 g of

  DEP, it is introduced into a mixer and then mixed at 30 ° C.

  20 minutes under reduced pressure with 160 g of lead salicylate having an average particle size of not more than 1 um and 80 g of copper benzoate having an average particle size of not more than 10 μm. again with 2000 g of RDX is then mixed at 400 C for minutes under reduced pressure with 160 g of 2-NDPA and 3040 g of NC in fine powder After mixing, the resulting slurry is cast in a mold under reduced pressure and cures the molded article at 50 OC for 10 days to obtain a CMDB propellant

  the propellant obtained in the same test as that described in Example 1.

  The results obtained are illustrated by the continuous curve of

Figure 4.

  Comparative Example 4 A CMDB propellant according to Example 4 is prepared, except that copper salicylate is used instead of copper benzoate. The propellant obtained is subjected to the same test as that described in Example 1. results obtained are illustrated by

  the discontinuous curve of Figure 4.

Example 5

  A CDB propellant is prepared in the following manner

  having the composition shown for Example 5 in the table.

  A mixture of 6000 g of NG and 400 g of

  DEP, it is introduced into a mixer and then mixed at 30 ° C.

  20 minutes under reduced pressure with 200 g of lead salicylate having an average particle size not exceeding H1 and 200 g of copper benzoate having an average

  particles of not more than 10 pm.

  for 20 minutes with an isocyanate-terminated bifunctional polyester having a molecular weight of 3,000 and then at 400 ° C for minutes under reduced pressure with 200 g of 2-NDPA and 2,600 g of NC in fine powder. After mixing, the resulting slurry is poured. in a mold under reduced pressure and the molded article is cured at 500 ° C. for 10 days to obtain a propellant CDB.

  the propellant obtained in the same test as that described in Example 1.

  The results obtained are illustrated by the continuous curve of the

figure 5.

  Comparative Example 5 A CBD propellant according to Example 5 was prepared, except that copper salicylate was used instead of copper benzoate. The propellant obtained was subjected to the same test as that described in Example 1. results obtained are illustrated by

  the discontinuous curve of Figure 5.

  The pressure exponent (n) of the formula described above is represented by the slope of a graph of the relationship between the combustion pressure (P) and the burning rate (r) on a log paper. following facts can be deduced from the inclination of the continuous curve of the examples and of

  the discontinuous curve of the comparative examples in the figures.

  Examples 1 to 3 and Comparative Examples 1 to 3 illustrate DB propellant embodiments As shown in the table, Examples 2 and 3 and Comparative Examples 2 and 3 illustrate embodiments of high-impulse DB propellants. Specifically, Example 1 and Comparative Example 1 illustrate embodiments of DB propellants that do not have

  a specific impulse as high.

  In Figure 1, although the DB propellant of Example 1 which employs a combustion catalyst according to the invention

  and the propellant DB of Comparative Example 1 which employs a catalyst

  The combustion lyseur commonly known, have a character of burning in mesa, it is obvious that the inclination of the curve of the exponent of pressure is more important for the propellant DB of Example 1 and that, moreover, the region of combustion in mesa is

  wider than the propellant DB of Comparative Example 1.

  In FIG. 2, the DB propellant of Example 2, produced using a combustion catalyst according to the invention, has a characteristic of

  combustion in mesa in the area of combustion pressures.

  the propellant DB of Comparative Example 2, produced with a commonly known combustion catalyst, does not

  the weakening of the slope of the curve of the expo-

  pressure in the region of high combustion pressures.

  In Figure 3, although the propellant DB of Comparative Example 3, produced using a currently known combustion catalyst, has a curve of the gently sloping pressure exponent in the region of high combustion pressures, the propellant DB of Example 3, produced using a combustion catalyst according to the invention, has a very gentle slope pressure exponent curve in the region of high combustion pressures and finally has a character of combustion in mesa and more, has a slope of the curve of the pressure exponent which, as a whole, is more

  as low as the propellant DB of Comparative Example 3.

  FIG. 4 illustrates embodiments of CMDB propellant. The CMDB propellant of Example 4, produced using a combustion catalyst according to the invention, has a slope of the curve of the considerably lower pressure exponent. the high pressure combustion region that the CMDB propellant of Comparative Example 4, produced using a commonly known combustion catalyst, and exhibits a character of combustion

practically in plateau.

  FIG. 5 illustrates embodiments of CDB propellant. The CDB propellant of Example 5 produced by using a combustion catalyst according to the invention has a curve of the pressure exponent which, as a whole, has a slope. softer than that of the CBD propellant of Comparative Example 5, produced using a currently known combustion catalyst, and

a low pressure exponent n.

  As shown by the examples described above, according to the invention, propellant compositions having a remarkably low pressure exponent are produced by using a particular combustion catalyst, and the invention is very effective in producing a composition. propulsive impulse

specific high.

  Of course, various modifications may be made by those skilled in the art to devices or methods that

  have been described only as non-limitative examples

  without departing from the scope of the invention.

BOARD

Example Comparative example

1 2 3 4 5 1 2 3 4 5

  CN 55.0 38> 0 44.0 30.4 261 () 55.0 38) 0 14.0 O 30.4 27.0

  NG 32> 0 49.0 44 <) 0 39.2 60.0 32.0 49.0 44.0 39.2 60.0

  D) EP 8 0 8.0 8.0 6.4 4) 0 8.0 8.0 8.0 6.4 4.0

  Binder 4.0 4.0 o Composition 2-NDPA 2> O 2.0 2,> 10 1.6 2.0 2.0 2.0 2.0 1) 6 2.0

M RDX 20.0 20.0 -

  Pb-Sa 2.0 2.0 1.6 2 0 2.0 2.0> 1.6 2.0

M>) 1.0 1.0

  Cu-Be 1.0 1.0 1.0 0.8 2.0 Cu-Sa 1.0 i,) (1.0 0.8 i, <* Specific impulse 22 23 23 24 24 23 23 23 24 29 (s) (P = 78.4) 23 26 24 2 ë 4 2 3 3 4 4 Nota NC nitrocellulose, NO nitroglycerine, DEP diethyl phthalate, isocyanate-terminated bifunctional polyester binder having a molecular weight of 30001, 2-NDPA 2-nitro-diphenylamine, RDX: cyclotrimethylenetrinitramine, Pb-Sa: lead salicylate,

  Pb O lead oxide, Cu-Be copper benzoate, Cu-Sa copper salicylate.

  *: The specific impulse is the value calculated by use of a theoretical calculation program

for rocket performance.

0%

Claims (3)

  A propellant composition containing at least nitrocellulose and nitroglycerine, characterized in that it contains, as combustion catalyst, copper benzoate and at least one constituent chosen from organic lead salts, metallic lead and the inorganic compounds of lead. 2 propellant composition according to claim 1, characterized in that the total amount of copper benzoate and at least one constituent selected from organic lead salts, lead metal and lead inorganic compounds, is 0.5 to 7% by weight relative to the total amount of the propellant composition. Propulsive composition according to Claim 2, characterized in that the amount of copper benzoate is   0.2 to 4% by weight relative to the total amount of the compound propulsion.