KR102621576B1 - A HIGH PERFORMANCE COMPOSITE PYROTECHNIC PRODUCT WITHOUT Pb IN ITS COMPOSITION, AND PREPARATION THEREOF - Google Patents

Abstract

The main object of the present invention is an efficient composite pyrotechnic product without lead in the composition, which can be produced on an industrial scale without suffering from pot life problems for the intermediate paste. The product contains an organic energy-generating filler and a combustion catalyst in a plasticized binder comprising a crosslinked energy-generating polymer and at least one energy-generating plasticizer. In a particular manner, the crosslinked energy-generating polymer has a number average molecular weight (Mn) in the range of 700 g/mol to 3000 g/mol, which is crosslinked through its hydroxyl terminal functional groups with at least one crosslinker of polyisocyanate type. ) consisting of glycidyl azide polymer (GAP) with; The combustion catalyst consists of bismuth citrate.

Description

High performance composite ignition product without Pb in the composition and method for manufacturing the same

The present invention relates to a composite pyrotechnic product particularly suitable for use as a solid propellant for propulsion in rocket engines. More precisely, the present invention relates to composite ignition products containing a high content of organic energetic fillers in an energetic binder. Said products do not contain any lead in their composition, they offer high performance, especially with regard to the combustion rate, and the potlife (before curing) of their precursor mixture (see definition below) is (on industrial scale) This has the particular advantage of being longer (by making it very easy to obtain such products).

Solid propellants of the composite type usually consist of a plasticized binder (a solid, usually plasticized, and optionally energy-generating polymer matrix - i.e. a hardened polymer) together with various additives, especially feasibility additives and performance additives. Powdered solid charges (oxidisable charges, and possibly also reducible charges).

The binder is obtained from a liquid polymer that is “curable” and has chemically reactive end groups suitable for curing by at least one curing agent (having at least two functional groups) that is itself liquid. Generally, other than the one or more curing agents (and, if such one or more curing agents (which are generally very sensitive to moisture) are used, one or more curing catalysts), in an appropriate sequence, one or more plasticizers are added to such liquid polymers. and other components of the propellant, and finally the one or more curing agents (and one or more curing catalysts, if used). The polymer with filler is then heat treated (“baked”) at a temperature compatible with the energy-generating material (minimal filler) present. Together with the present plasticizer(s), the cured polymer constitutes a plasticized binder that coats all the components, and especially the powder charge, to form a solid body.

The method practiced for producing these composite fired products in the form of blocks is a discontinuous process, referred to as a “batch” method, which consists of preparing a certain amount of paste, a certain amount (or at least a portion thereof) It consists of casting in a number of structures (one or more structures) and applying heat treatment to the charge(s) obtained in this way (to harden the polymer). At an initial stage, the various components are thus injected in the appropriate sequence, and then they are carefully mixed over a long period of time under very specific conditions of temperature and pressure (usually partial vacuum). For the subsequent steps, the mixture, thus in the form of a paste, is cast into one or more structures (which structures are possibly used with equipment for molding within the structures). The assembly is then heat treated (baked) to harden (solidify) the polymer. In most circumstances, the structure constitutes an actual casting of the charge.

At least one curing agent (and one or more curing catalysts, if present) are injected into the mixture at the end of the mixing step. Specifically, when pouring begins, the paste - which is already more or less viscous in nature depending on the nature of the polymer, the content of fillers, etc. - begins to harden (“solidify”). Accordingly, casting can occur for a limited period of time, referred to as “pot life”, during which the mixture allows sufficient fluid to be cast. For industrial work, it is essential to ensure that the pot life of the paste is sufficiently long (to allow sufficient time for the various casting operations).

The pot life of a propellant paste is evaluated by measuring how the viscosity of the paste changes over time. From a viscosity greater than 1.5 kPa.s = 15 kPo (15 kP), the propellant paste is considered no longer “castable” and a time shorter than 15 hours (h) to reach this viscosity is not sufficient for any of the present methods. It is considered to hinder industrialization. The paste has a viscosity of less than 1.5 kPa.s = 15 kPo at the end of 15 hours, which is a (necessary but sufficient) condition to ensure that the paste can be cast under industrial conditions. Of course, those skilled in the art will understand that the pot life of a paste depends on the exact conditions (of temperature and pressure) under which the paste is cast.

In order to increase the combustion rate of solid propellants, it is known to add agents to their compositions that act as combustion catalysts (which are also referred to as ballistic catalysts). Organometallic salts of lead and oxides of lead have been used for this purpose in the past. Because of its toxicity, lead has recently been replaced by bismuth; This is why salts and oxides of bismuth are used as combustion catalysts in solid propellants.

Accordingly, the patent application FR 2 727 401 discloses bismuth as a combustion catalyst for double base solid propellants (nitrocellulose and at least one nitric acid ester such as nitroglycerin) or complex double base solid propellants (charge in energy-generating binders based on nitric acid esters). The use of salts such as bismuth β-resorsylate, bismuth γ-resorsylate, bismuth salicylate, bismuth citrate, bismuth stearate, and the use of bismuth oxide are described.

Nevertheless, the use of these new combustion catalysts presents disadvantages insofar as they are also curing catalysts and their use shortens the pot life (see above).

Patent US 6 183 574 discloses compositions of composite propellants (energogenic binders of (nitramine type: ORP-2 (see below)) cured by polyisocyanates or non-energogenic binders (polyglycol adipate (PGA), capro lactone), the presence of bismuth salts, most especially the presence of bismuth salicylate and the presence of bismuth β-resorsylate, causes a significant shortening of the pot life, which means that the bismuth salt (combustion catalyst) also cures. We confirm that this is because it acts as a catalyst. The patent proposes a "processing trick" to limit this shortening of pot life. This is done at approximately 32°C-38°C (90°C) as in the conventional method. It is proposed to inject a bismuth salt into a propellant paste (made upstream) that is cooled to about 16°C (60°F) instead of to a temperature in the range of -100°F. For this further cooling, the intrinsic paste viscosity decreases. It can be understood that a further increase of The polymer must be able to be cast at such low temperatures.

16℃)에서 캐스팅될 수 있다 (특허 US　6　168　677의 표 10 참조).Patent US 6 183 677 confirms the teachings of patent US 6 168 574. It describes and evaluates composite propellants containing in their composition bismuth salicylate and/or bismuth citrate as ballistic catalysts and having an energizing binder that is cured with a polyisocyanate. The energy-generating binders described are of the ORP-2 type (poly(diethylene glycol-4,8-dinitrazuanedecanoate) and the 9DT-NIDA type (diethylene glycol-triethylene glycol-nitraminodiacetic acid terpolymer). (Acid) A binder of the nitramine type obtained from polymers. These polymers can be used at low temperatures, up to 60°F (

16° C. (see Table 10 of patent US 6 168 677).

Until now, those skilled in the art have always been seeking high-energy-generating, high-performance propellants that incorporate non-toxic (lead-free) ballistic catalysts in their composition, which can be achieved by using pastes that provide a sufficiently long pot life. It can be obtained on an industrial scale and can be operated under favorable and simple conditions, especially with regard to the processing temperature.

In this context, the applicant has proposed a novel novel device having a specific energy-generating binder (comprising a specific energy-generating polymer (GAP) cured with at least one polyisocyanate) and containing in its composition a specific combustion catalyst (bismuth citrate). A composite propellant is proposed. This novel composite propellant of lead-free composition offers high performance in terms of energy (in particular, it provides a rapid combustion rate) and the process for its preparation is particularly advantageous. The Applicant has discovered that, when conventionally used with polyisocyanate(s), plasticizer(s) and organic energy-generating fillers, they are in the form of a paste prior to curing and do not contain a combustion catalyst in their composition or contain a combustion catalyst in their composition. to have the advantage of selecting a pair comprising a combustion catalyst and a precursor polymer for an energy-generating binder resulting in a propellant that provides a pot life close to that of similar propellants containing lead citrate; This applies at temperatures in the range 35°C-55°C (this temperature, above ambient temperature, is entirely suitable for the “simple” operation of the method for producing said propellant (see below)).

In a first aspect, the present invention thus provides a novel, high-energy-generating composite ignition product that does not contain lead in its composition. This is the type with a curable energy-generating binder containing organic energy-generating fillers. More precisely, it contains an organic energy-generating filler and a combustion catalyst in a plasticized binder comprising a curable energy-generating polymer and at least one energy-generating plasticizer. The specific method is as follows:

상기 경화형 에너지발생 폴리머(cured energetic polymer)는 폴리시이소시아네이트 유형의 적어도 하나의 경화제와 함께 이의 하이드록실 말단 작용기를 통해 경화되는, 700　몰당 그램 (g/mol) 내지 3000　g/mol의 범위의 수평균 분자량 (Mn)을 갖는 글리시딜 아지드 폴리머 (GAP)로 이루어지고; 그리고

The cured energetic polymer has a number average molecular weight in the range of 700 grams per mole (g/mol) to 3000 g/mol, which is cured through its hydroxyl terminal functional groups in combination with at least one curing agent of the polyisocyanate type. consists of glycidyl azide polymer (GAP) with (Mn); and

연소 촉매는 비스무스 시트레이트로 이루어진다.

The combustion catalyst consists of bismuth citrate.

The structure of the composite combustion product of the invention is thus related to the specific mode, the specific binder and the specific combustion catalyst. This connection will be found to be particularly advantageous with reference to the present specification, which contains two conditions contrary to the prior art: the product has high energy generation performance (rapid combustion speed) (requires the presence of an effective amount of combustion catalyst) must be provided; And the method of obtaining it must be easy (most especially with regard to the lifetime of the cured paste (regarding the issue of "pot life")).

Therefore, the properties of the binder (as well as the properties of its precursor polymer) constitute one of the important ingredients for the composition of the composite fire product of the present invention.

It will be observed that the term “one” glycidyl azide polymer (= precursor polymer for the binder) is to be understood throughout this specification as “at least one” glycidyl azide polymer. Specifically, the scope of the present invention is to provide different molecular weights and/or different degrees of branching (in the range of 700 g/mol to 3000 g/mol) to be used as precursor polymers for the binders in the products of the present invention. ) do not exclude in any way mixtures of at least two glycidyl azide polymers.

Accordingly, the energy-generating polymer selected as a precursor for the binder in the product of the present invention is characterized by 1) its energy-generating properties; and 2) glycidyl azide polymer (GAP), an azide polymer that provides hydroxy terminal functionality (hydroxytelechelic GAP), which confers its ability to be cured with polyisocyanate type curing agents.

The polymer has a suitable molecular weight (related in particular to its (liquid) consistency and the concentration of its essential mixture with the filler (organic energizing filler) and to the relative hardener(s) content of the curable binder), 700 g/ It has a number average molecular weight (Mn) in the range from mol to 3000 g/mol, advantageously in the range from 1700 g/mol to 2300 g/mol.

The present inventors have the advantage of identifying (selecting) a binder of this type (its precursor polymer) so that it is fully suitable for the use of bismuth citrate as a combustion catalyst.

Curing agents of the polyisocyanate type (with two or more functional groups) suitable for curing these hydroxytelechelic glycidyl azide polymers (GAP) are known per se. This may in particular be a di- or tri-isocyanate. Advantageously, these are toluene diisocyanate (TDI), isophorone diisocyanate (IDPI), methylene dicyclohexyl diisocyanate (MDCI), hexamethylene diisocyanate (HDI), trimers of said hexamethylene diisocyanates (especially those under the trade name Desmodur ® N 3300), biuret trihexane isocyanate (BTHI), 3,5,5-trimethyl-1,6-hexamethylene diisocyanate, and mixtures thereof. In a particularly preferred manner, hexamethylene diisocyanate trimer is used.

The curing agent is used conventionally in an amount essential and sufficient to ensure that the polymer is cured (not excessively to avoid contaminating the resulting cured product). They are used in such an amount that the crosslinking ratio of NCO (from the curing agent) to OH (of the polymer) ranges from 0.8 to 1.4, and is advantageously equal to 1.

The curable energy-generating polymer generally represents 10% to 14% by weight of the total composition of the composite fired product of the present invention. The energy-generating polymer itself generally makes up 8 to 12 weight percent, and the at least one curing agent represents about 2 weight percent.

It is clearly understood that although the properties of the binder (of its precursor polymer) are not inherent per se, the advantage of the invention lies in the association of this binder (of its precursor polymer) with a particular combustion catalyst.

In a conventional manner, the energizing binder is associated with at least one energizing plasticizer. The energy-generating plasticizer(s) in question are advantageously of the nitrate and/or nitramine type. The energy-generating plasticizer(s) in question are diethylene glycol dinitrate (DEGDN), triethylene glycol dinitrate (TEGDN), butanetriol trinitrate (BTTN), trimethylolethane trinitrate (TMETN), 2 , a mixture of 4-dinitro-2,4-diaza-pentane, 2,4-dinitro-2,4-diaza-hexane, and 3,5-dinitro-3,5-diaza-heptane ( Most especially DNDA 5.7), nitrato ethyl nitramine (and especially methyl-2-nitratoethyl nitramine (methylNENA), and ethyl-2-nitratoethyl nitramine (ethylNENA)), and mixtures thereof. The most advantageous choice is made.

The plasticizer(s) of the fired products of the invention generally represent 10% to 30%, more typically 15% to 25%, by weight of the total composition of the product.

The energy generating filler provided is an organic filler.

The organic energy-generating charge in question is not original. These are already known organic energy-generating fillers, which for the most part are already suitable from the prior art in curable energy-generating polymer binders (especially those of the GAP type). Advantageously, these are hexogen (RDX), octogen (HMX), hexanitrohexaazysourzytane (CL20), nitroguanidine (NGU), ethylene dinitramine (EDNA), N-guranylurea dinitramide. (FOX 12 (GUDN)), 1,1-diamino-2,2-dinitro ethylene (FOX 7 (DADE)), bis(triaminoguanidinium)-5,5'-azotetrazolate (TAGZT) ), dihydrazinium 5,5'-azotetrazolate (DHDZT), 5,5'-bis(tetrazolyl)hydrazine (HBT), bis(2,2-dinitropropyl)nitramine (BDNPN), and nitropyrazole fillers, or mixtures of such (organically energizing) fillers.

In the composite combustion product of the invention, one type of energy-generating filler is thus found, advantageously selected from those listed above, or a mixture of at least two types of energy-generating fillers advantageously selected from those listed above. . In a preferred manner, an energizing RDX charge is present therein.

Organic energy-generating fillers are conventionally in the form of solid granules uniformly dispersed in a plasticized hardenable binder. In a known manner, these solid granules advantageously provide a plurality of granule size distributions.

The organic energy-generating filler of the incendiary product of the present invention generally constitutes 50% to 70%, more typically 55% to 65%, by weight of the total composition of the product. The product can be understood as having a high filler content.

The presence of inorganic energy-generating fillers in the plasticized binder of the fired product of the invention is not completely excluded. In any case, these inorganic energizing charges, if present, should be present in small amounts (less than 4% by weight). This may be considered an additive (see below). Its presence may be advantageous with regard to the ballistic properties of the product; Nonetheless, they should not form large amounts of combustion smoke or light.

On the other hand, the presence of metal fillers in the plasticized binder of the fired products of the invention is generally excluded. Specifically, upon combustion, these metal charges can produce particulates.

The nature of the combustion catalyst present constitutes another important component in the composition of the composite combustion product of the present invention. The combustion catalyst consists of bismuth citrate. Due to its reduced toxicity, said bismuth citrate advantageously replaces the salts and oxides of lead of the prior art. Additionally, surprisingly, the specific combustion catalyst comprised of bismuth citrate in the specific plasticized binder of the incendiary product of the present invention has a significant effect on combustion (most particularly on combustion rate) without causing upstream problems in the manufacturing process of the product. ) has a positive effect (the manufacturing method is at "constant temperature" until the polymer hardens, and in some cases does not involve any significant cooling (of the type described in US patents US 6 168 574 and 6 168 677) , it is generally implemented “easily” without any problems managing available time). For this topic, the reader may consider the results in Table 2 below.

Bismuth citrate (combustion catalyst) is generally present in the composition of the combustion product of the invention in an amount ranging from 1% to 6% by weight, very typically in an amount ranging from 3% to 5% by weight.

In these binders (cured precursor polymers), the composite fire products of the invention may also contain, or usually do contain, at least one additive as well as plasticizer(s), organic energy-generating fillers, and (certain) combustion catalysts. . It is more accurate to refer to at least one “other” additive, since combustion catalysts generally constitute an additive. Combustion catalysts are herein separated from other additives insofar as they constitute an important component of the product of the invention, leaving aside the technical problems considered herein and the (particular) combustion catalyst selected.

Among the additives advantageously present, the following conventional additives may be preferred: curing catalysts and stabilizers for the energy-generating plasticizer(s) present. Accordingly, in an advantageous variant, the composite combustion product of the invention thus comprises in its composition at least one additive other than a curable polymer (GAP), a plasticizer(s), an organic energy-generating filler, and a combustion catalyst (bismuth citrate). do; The at least one additive includes at least one curing catalyst and/or at least one stabilizer to the plasticizer(s) present. Said at least one polymerization catalyst may in particular be selected from triphenylbismuth and dibutyl tin laurate (DBTL). When present, it is generally present in amounts not exceeding 100 parts per million (ppm). Said at least one stabilizer for stabilizing the plasticizer(s) present consists in particular of at least one aromatic amine, such as 2-nitrodiphenylamine (2-NDPA), and N-methyl para nitroaniline (MNA). When present, it is generally present in an amount of about 1% by weight.

Other additives that may be present in the composition of the composite fire product of the invention may consist, inter alia, of inorganic energy-generating fillers (see above), one or more agents (processing aid(s)). The agent(s) are generally present in amounts ranging from 1% to 2% by weight.

The additives optionally present (in view of the above description, it may be understood that multiple types of additives are generally present) generally represent no more than 4% by weight of the composition of the composite fire-fighting product of the invention. Most commonly, it represents 0.1% to 4% by weight of the composition of the composite fire-starting product of the present invention.

In view of the above description, the composite combustion products of the present invention are not of a new type, but are considered novel by associating in their composition a specific binder (at least GAP cured by polyisocyanate) and a specific combustion catalyst (bismuth citrate). It can be understood.

In the context of an advantageous variant, the composition of the composite fire product of the invention, expressed in weight percentages, comprises:

50% 내지 70%, 유리하게는 55% 내지 65%의 유기 에너지발생 충전물; 및

50% to 70%, advantageously 55% to 65% of organic energy-generating charge; and

10% 내지 14%의 에너지발생 폴리머 (적어도 하나의 폴리이소시아네이트에 의해 이의 하이드록시 말단 작용기를 통해 경화되는 하이드록시텔레켈릭 GAP 유형의 것);

10% to 14% of an energy-generating polymer (of the hydroxytelechelic GAP type, which is cured through its hydroxy terminal functional groups by at least one polyisocyanate);

10% 내지 30%, 유리하게는 15% 내지 25%의 적어도 하나의 에너지발생 가소제;

10% to 30%, advantageously 15% to 25% of at least one energy-generating plasticizer;

1% 내지 6%, 유리하게는 3% 내지 5%의 비스무스 시트레이트; 및

1% to 6%, advantageously 3% to 5% of bismuth citrate; and

0 내지 4%, 유리하게는 0.1% 내지 4%의 적어도 하나의 첨가제.

0 to 4%, advantageously 0.1% to 4% of at least one additive.

It can be understood that the above-mentioned advantageous ranges can be considered completely independent of each other. Preferably, these are considered to be combined with each other.

In the context of an advantageous variant, the composition generally does not contain any other components (in particular any metal fillers), and thus it consists of the above-listed components present in the above-specified amounts.

The great advantages of the product of the present invention can be clearly seen from the above description. As long as the pot life of the (precursor) paste containing the above ingredients is close to that of the paste for a similar propellant not containing bismuth citrate, the product (with respect to its ballistic performance, and its mechanical properties and propellant combustion (injection ) is advantageous in itself due to the small signature of the plume generated during the process. More generally, it has been found that the production of the product of the invention is not difficult to carry out and that this practice is “optimized” in terms of temperature management.

In a second aspect, the present invention provides a method for producing the above-described composite fired product. The method includes:

하기 단계 a) 및 b)에 의해 균질한 페이스트를 제조하는 단계;

Preparing a homogeneous paste by the following steps a) and b);

a) a suitable glycidyl azide polymer (hydroxytelechelic GAP exhibiting the number average molecular weight specified above) at a temperature in the range from 35° C. to 55° C., at least one energy-generating plasticizer, an organic energy-generating filler, and optionally Excluding the curing agent and any curing catalyst, incorporating other ingredients (including the specific combustion catalyst: bismuth citrate) that make up the desired composite ignition product; and

b) stirring the resulting mixture under partial vacuum at a temperature in the range of 35° C. to 55° C. (advantageously at said temperature);

35℃ 내지 55℃의 범위의 온도에서 (유리하게는 상기 온도에서) 부분 진공 하에, 상기 생성된 균질한 페이스트에 상기 적어도 하나의 경화제 및 임의로 적어도 하나의 경화 촉매를 혼입하고, 이후 생성된 혼합물을 교반하는 단계;

Incorporating said at least one curing agent and optionally at least one curing catalyst into said resulting homogeneous paste under partial vacuum (advantageously at said temperature) at a temperature in the range of 35° C. to 55° C. and then mixing the resulting mixture with said at least one curing agent. stirring;

생성된 교반 혼합물 (= 수득된 혼합물)을 적어도 하나의 구조물에서 캐스팅하는 단계; 및

Casting the resulting stirred mixture (=obtained mixture) in at least one structure; and

상기 적어도 하나의 구조물에서 캐스팅된 것으로서 상기 생성된 교반 혼합물 (교반된 것)을 열 처리하는 단계.

Heat treating the resulting stirred mixture (stirred) as cast in the at least one structure.

The partial vacuum specified is intended to degas the medium to which it is applied. A vacuum is typically 10 milliliters of mercury (mmHg). It will be observed that its value is not necessarily constant.

The heat treatment (to cure the hydroxytelechelic GAP) is generally carried out at temperatures ranging from 30° C. to 60° C. (30° C. ≤ T ≤ 60° C.) for several days.

The present method can be considered a heuristic method, but in a certain way, due to the specific properties of the binder (the precursor polymer for it) and due to the specific properties of the combustion catalyst, its initial stages are carried out without cooling and without any of the polymers. It is carried out at a temperature in the range of 35°C to 55°C (35°C ≤ T(s) ≤ 55°C) (advantageously at one temperature) without the pot life problem.

The invention is illustrated below by the following examples. More precisely, examples A, B1, and B2 illustrating the prior art, examples 1 and 2 illustrating the invention, and comparative examples C1 and C2 are presented below.

Examples 1 and 2 relate to the propellant of the present invention, the composition of which contains a hexogen (RDX) filler, cured (by hexamethylene diisocyanate trimer, sold by the supplier Bayer under the trade name Desmodur® N 3300), ( Plasticized (supplied by Eurenco (Mn) by a mixture of two energy-generating plasticizers (BTTN/TMETN; 30/70 (% by weight)) and a stabilizer for the plasticizers (MNA/2-NDPA; 75/25 (% by weight) (number average molecular weight) = 1900 (g/mol)), a binder based on energy-generating polymers of the hydroxytelechelic PAG type, and bismuth citrate as a carbon catalyst (content of 1% by weight in Example 1 and A content of 4% by weight in Example 2).

The propellants of Examples 1 and 2 were compared with reference propellants, one of which (Reference Example 1) did not have a ballistic catalyst in its composition (Example A) and the other (Reference Example 2) had its The composition had lead citrate as ballistic catalyst in an amount of 1% by weight (Example B1) and 3.5% by weight (Example B2).

Two comparative examples also describe propellants similar to those of inventive example 2, but comprising bismuth subsalicylate (C1) and bismuth carbonate (C2) replacing bismuth citrate as the ballistic catalyst. .

The composition of this propellant (more precisely the composition of its paste before curing) is given in Table 1 below.

The same ingredients were originally used for all examples. Considering the RDX charge, it consisted of 68% by weight RDX with a granule size rating of 0 - 100 micrometers (μm) and 32% by weight RDX with a granule size rating of 2.5 μm - 5 μm.

[Table 1]

In this way, a composite ignition product (propellant) was prepared, the composition of which was given by weight in Table 1 above. For this purpose, the method described below was implemented (see the following paragraph under the heading “Preparation”).

The pot life of the propellant paste (intermediate) produced was noted. The pot life was determined by performing the viscosity measurements described below (see the section entitled “Determination of pot life” below). The results are shown in the first part of Table 2 below.

In the second part, Table 2 above also includes combustion rate results measured at different pressures for the final obtained propellant.

Recipe

The following were charged to the mixer: glycidyl azide polymer (GAP) as binder precursor polymer; Then a plasticizer (BTTN/TMETN) and a stabilizer for the plasticizer (MMA/2-NDPA). The mixture was mixed for 15 minutes (min) at a temperature of 40°C.

The following were then added to the above mixture under stirring: organic energy-generating filler (RDX) portionwise; subsequent additives (other than hardeners and catalysts (Desmodur® N'3330 and DBTL)); and combustion catalyst. Stirring was then continued for 2 hours and 30 minutes at a temperature of 40°C and a vacuum of 10 mmHg (capable of degassing the medium) to obtain a homogeneous paste.

Curing catalyst (DBTL (55 ppm)) was then added to the homogeneous paste and agitation of the medium was continued for 30 minutes before adding the curing agent to the binder. The curing agent (Desmodur® N3300) was finally added and stirring of the medium (under vacuum at 40° C.) was continued for 15 minutes.

The propellant paste was then prepared in 2 kilogram (kg) batches.

Samples were taken of each propellant paste as prepared in that manner to determine pot life.

The remaining respective prepared propellant pastes were then cast in appropriate structures and heat treated as follows: baking at a temperature of 50° C. for 75 hours.

of paste Determination of available time

The pot life is determined by measuring the viscosity of the propellant paste in question (containing hardener and curing catalyst) at a temperature of 40°C using a Brookfield viscometer (using No.3 body (mobile phase C) rotating at 1 revolution per minute (rpm)). was determined by measuring over time. The time for the viscosity to reach 15 kPo was measured to determine whether it was a propellant suitable for industrialization standards, that is, whether the measurement time was longer than 15 hours.

[Table 2]

The themes of the results in Table 2 are explained as follows.

Available time

As expected, the pastes of the reference propellants without ballistic catalyst (Example A) or containing lead citrate as ballistic catalyst (Examples B1 and B2) reached a viscosity value of 15 kPo after 24 hours; Accordingly, the criteria for industrial castability were met.

The propellant paste of Example 1 (inventive) incorporating bismuth citrate at an amount of 1% by weight is a casting equivalent to that of the propellants of Reference Examples A (without ballistic catalyst) and B1 (with Pb citrate at 1% by weight). Possible characteristics are shown.

Example 2 (of the invention) shows that even at a high content of bismuth citrate (4% by weight), the propellant paste retained a viscosity of less than 15 kPo for at least 16 hours, which makes it suitable for industrial casting of the paste. is longer than the minimum time of 15 hours (required to perform).

The viscosity of the propellant pastes of Comparative Examples C1 and C2 exceeded the maximum allowable viscosity value (15 kPo) in less than 1 hour (which is much shorter than the required 15 h). This shows that it is particularly suitable to select a pair comprising PAG and bismuth citrate according to the invention.

combustion speed

Additionally, Table 2 shows that the ballistic catalyst (combustion catalyst), i.e. bismuth citrate, is larger than that of reference propellant A (which does not have a carbon catalyst in its composition) and contains lead citrate (a toxic product) as combustion catalyst. It is shown that the composition imparts a combustion rate to the propellant of the present invention as a function of pressure that is close to that of propellants B1 and B2.

Claims (11)

A composite pyrotechnic product containing an organic energetic charge and a combustion catalyst in a plasticized binder comprising a cured energetic polymer and at least one energy-generating plasticizer,

The curable energy-generating polymer is a glycidyl acetate having a number average molecular weight (Mn) in the range of 700 g/mol to 3000 g/mol, which is cured through its hydroxyl terminal functional groups with at least one curing agent of the polyisocyanate type. Made of azide polymer (GAP); and

The combustion catalyst is made of bismuth citrate.
A composite ignition product, characterized in that. The composite fire product according to claim 1, wherein the glycidyl azide polymer (GAP) has a number average molecular weight (Mn) in the range of 1700 g/mol to 2300 g/mol. The product according to claim 1, wherein the at least one energy-generating plasticizer is of the nitrate and/or nitramine type. The method of claim 1, wherein the organic energy generating filler is hexogen, octogen, hexanitrohexaazysourzytane, nitroguanidine, ethylene dinitramine, N-guanylurea dinitramide, 1,1-diamino- 2,2-dinitro ethylene, bis(traaminoguanidinium)-5,5'-azotetrazolate, dihydrazinium 5,5'-azotetrazolate, 5,5'-bis(tetrazolyl ) hydrazine, bis(2,2-dinitropropyl) nitramine, and nitropyrazole fillers, and mixtures of these fillers. 2. A composite fire-fighting product according to claim 1, characterized in that it contains from 1% to 6% by weight of said bismuth citrate. 6. A composite fire-starting product according to claim 5, characterized in that it contains from 3 to 5% by weight of said bismuth citrate. The composite fire-starting product according to claim 1, characterized in that it further contains at least one additive. 8. A composite fire product according to claim 7, wherein the at least one additive comprises at least one curing catalyst and/or at least one stabilizer for the at least one energy-generating plasticizer. The composite fire product according to claim 1, wherein the composition contains, expressed in weight percentages:

50% to 70% of the organic energy generating filler;

10% to 14% of the curable energy-generating polymer;

10% to 30% of said at least one energy-generating plasticizer;

1% to 6% of the bismuth citrate; and

0 to 4% of at least one additive. The composite fire product according to claim 1, wherein the composition contains, expressed in weight percentages:
55% to 65% of the organic energy-generating filler;
10% to 14% of the curable energy-generating polymer;
15% to 25% of said at least one energy-generating plasticizer;
3% to 5% of the bismuth citrate; and
0.1% to 4% of at least one additive. A method for producing a composite fire product according to any one of claims 1 to 10, comprising:

Preparing a homogeneous paste by steps a) and b) below;
a) said glycidyl azide polymer at a temperature in the range of 35° C. to 55° C. mixing other ingredients that make up; and
b) stirring the resulting mixture under partial vacuum at a temperature in the range of 35° C. to 55° C.;

Incorporating the at least one curing agent and optionally at least one curing catalyst into the resulting homogeneous paste under partial vacuum at a temperature in the range of 35° C. to 55° C. and then stirring the resulting mixture;

casting the agitated product mixture in at least one structure; and

heat treating the cast agitated product mixture in the at least one structure
A manufacturing method comprising: