JPH08259366A - Solid propellant containing azido group and nitrato group - Google Patents

Abstract

PURPOSE: To obtain a solid propellant having high specific impulse and burning velocity and lowered pressure index by compounding a lead compound and carbon to a composition containing a specified fuel binder and oxidizing agent. CONSTITUTION: This solid propellant is produced by compounding a lead compound and carbon to a composition composed of a fuel binder composed mainly of a prepolymer having azido group and nitrato group and an oxidizing agent consisting of nitramine. Among the azido group-containing prepolymers, 3,3-bis(azidomethyl)oxetane has the highest azido group content and gives high energy, however, the polymer is solid at normal temperature. It can be converted into a polymer exhibiting liquid state at normal temperature by copolymerizing with 3-nitratomethyl-3-methyloxetane containing nitrato group and expressed by formula. In the formula, R1 is CH2 N3 , R3 is CH2 ONO2 and R3 is CH3 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid propellant having an energetic prepolymer containing an azide group and having a catalyst incorporated therein to improve combustion characteristics.

[0002]

2. Description of the Related Art Conventional solid propellants are roughly classified into composite propellants consisting of an oxidizer and a fuel component, and double-base propellants consisting mainly of nitroglycerin and nitrocellulose.

Ammonium perchlorate, ammonium nitrate, etc. are used as the oxidizer used in the composite propellant, polyurethane, polybutadiene, etc. are used as the fuel / binder, and aluminum powder etc. are used as the other metal fuel. Is used. This composite propellant
It is widely used because it has a higher specific thrust than double-base propellants.

However, the most widely used composite propellant using ammonium perchlorate as an oxidant is a nitramine compound containing no chlorine in the molecule as an oxidant because of the problem of hydrogen chloride produced during combustion. Recently, research on smokeless composite propellants has been actively conducted.

Further, in order to supplement the oxygen deficiency of the nitramine compound and improve the combustion performance, a fuel component with a high energy has been used as a so-called binder. Polymers having azide groups that generate a large amount of heat of reaction by generating nitrogen molecules by thermal decomposition, and those that have a large amount of oxygen in the molecule and gas generated by thermal decomposition are currently being researched as the binder. Polymers having a large amount of nitrato groups have received attention.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Polymer having azide group and nitrato group in binder
The propellant using is problematic in that it has a very high pressure index in combustion performance. It is empirically known that the combustion speed r generally satisfies the following relationship: r = aP ⁿ a: constant P: pressure n: pressure index. This means that the combustion speed increases as the combustion pressure increases, but when n is large, it means that the combustion speed changes significantly with a slight pressure increase.

Therefore, it is difficult to obtain a highly reliable rocket unless the combustion area and the nozzle slot area are maintained extremely accurately in order to suppress fluctuations in combustion pressure. In order to avoid this, the pressure index n is generally preferably 1.0 or less, and currently 0.5 or less is used as a solid propellant.

Under the circumstances, the present invention provides a solid propellant having a large specific thrust and a high burning rate and a reduced pressure index of the solid propellant using a polymer containing an azide group and a nitrato group. The purpose is.

[0009]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventors in view of the above problems, a prepolymer whose main component of a fuel binder contains an azide group and a nitrato group, preferably 3,3. -Bis (azidomethyl) oxetane and 3-
Nitratomethyl-3-methyloxetane as a fuel binder with cyclo-1,3,5-trimethylene-
2,4,6-trinitramine (RDX), cyclo-1,
Lead citrate on nitramine such as 3,5,7-tetramethylene-2,4,6,8-tetranitramine (HMX),
By blending lead stearate, an organic lead compound such as lead ethylhexanoate, and carbon, it has been found that smokeless, high energy and pressure index can be lowered, and the present invention has been completed. It was

The azido group-containing prepolymer used in the present invention is not particularly limited as long as it is an azide group-containing polymer, and for example, 3-azidomethyl-3-
Methyloxetane (AMMO), glycidyl azide polymer (GAP), 3,3-bis (azidomethyl) oxetane (BAMO) and the like are common.

As the nitrato group-containing prepolymer, 3-nitratomethyl-3-methyloxetane (NM
MO), 3,3-bis (nitratomethyl) oxetane (BNMO) and the like are common.

Of these, BAMO has the highest content of azide groups and therefore has a high energy, but this polymer is
Is a solid at room temperature. Therefore, it can be liquefied at room temperature by copolymerizing with NMMO containing a nitrato group as represented by the following formula (1) (USP 5099).
042) can be used as a fuel binder as a propellant.

[0013]

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Note: The above includes block copolymers and random copolymers.

The prepolymer copolymer may be copolymerized by adding a third component such as oxetane or tetrahydrofuran, or such a third component may be added. Since these prepolymers have a terminal hydroxyl group and are used as a binder containing these as a main component, the curing agent is an isocyanate compound that reacts with the hydroxyl group, such as tolylene diisocyanate, isophorone diisocyanate, and hexa. Methylene diisocyanate-diphenylmethane diisocyanate
, Triphenyldimethylene triisocyanate, triphenylmethane triisocyanate and the like are used.

The crosslinking agent is a compound having a polyfunctional hydroxyl group,
For example, trimethylolethane, trimethylolpropane, glycerin, hexanetriol, diglycerin and the like, and polyfunctional isocyanates are used.

The plasticizer may be an ester type such as dioctyl adipate or diethyl phthalate, or di (butyl diglycolate).
(L) A compound having a good compatibility with the prepolymer such as a compound having an ester bond with an ether such as adipate is used.

The curing catalyst is butyltin trichloride,
Organotin compounds such as dibutyltin diacetate and dibutyltin dilaurate, and organic iron compounds such as ferric acetylacetone and ferric diphenylacetylacetone are used.

As the lead compound to be added, an organic lead compound such as lead citrate, lead stearate or lead 2-ethylhexanoate is used. At that time, it is necessary to add carbon, and the lead compound alone does not show the effect. Particularly, lead citrate is most preferable among the lead compounds.

The added amount is 0.5 to 5%, preferably 2 to 4%, based on the solid propellant, and the pressure index at this time shows the lowest value, and below this, the effect is not exhibited. No
Further, if it is added more than that, there is no effect and the energy is lowered. The amount of carbon added is 0.1 to 3%, preferably 0.3 to 0.8%, based on the solid propellant. If it is more than 3%, the viscosity of the propellant increases and the manufacturability is poor, and if it is less than 0.1%, the effect is not exhibited.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples.

Various propellants having the compositions shown in Table 1 were produced. As the azide group- and nitrato group-containing prepolymer, a BAMO / NMMO copolymer having a molar ratio of 7: 3 was used. First, a prepolymer, a curing catalyst, a cross-linking agent, a plasticizer and a curing agent are heated and mixed, a combustion catalyst is added thereto, and ammonium perchlorate is further added, followed by mixing and mixing.
Defoamed. Curing was carried out at 60 ° C. for about 7 days.

[0023]

[Table 1]

Using various propellants shown in Table 1, the burning rate and the like were examined by the following method.

Solid propellant with an outer diameter of 7 mm square and a length of 70 mm
A resin layer (combustion control layer) having a thickness of about 1 mm was formed on the side surface of the column, which was cut out into a cylinder, to prepare a sample. Such samples are commonly referred to as strand propellants. A nichrome wire for ignition was passed through about 10 mm from one end of the strand propellant, and a fuse wire was passed through 20 mm and 60 mm from one end. The strand propellant was sealed in a pressure vessel, and the nichrome wire was energized and ignited by burning with the nichrome wire under pressure to remove the space between the fuse wires (here, 40 mm) by the time difference between the two fuse wires. The burning velocity is defined as the value. This measurement is performed under pressure, but using a strand combustor in which a combustion container and a pressure accumulator having a sufficient capacity to maintain a constant pressure during combustion of the strand propellant are connected, Set, pressurize to a predetermined pressure with nitrogen gas, and then ignite.

In this way, the burning rate was measured repeatedly while changing the pressure applied.

The burning rates of the various propellants obtained are shown in Table 2.

[0028]

[Table 2]

[0029]

As described above, in the solid propellant in which the main component of the fuel binder is a polymer containing an azide group and a nitrato group, the following characteristics are obtained by including a lead compound and carbon as components. Was found to have.

1. The pressure index is much lower than the conventional value, which facilitates the design of rocket motors and provides a highly reliable propellant for rocket motors.

2. The burning rate also doubled on the low pressure side, and the range of application of the solid propellant could be expanded.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Anan 2620 Oji-ri, Oita-shi, Oita Prefecture Asahi Kasei Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A solid comprising a prepolymer containing an azide group and a nitrato group as a main component of a fuel binder, and a lead compound and a carbon compounded in a composition in which the oxidant is nitramine. Propellant. 2. The prepolymer is a copolymer of 3,3-bis (azidomethyl) oxetane and 3-nitratomethyl-3-methyloxetane.
The solid propellant described. 3. The lead compound is an organic lead compound such as lead citrate and lead stearate, and is 1 to 3 relative to the solid propellant.
The solid propellant according to claim 1, wherein the solid propellant is contained in a weight percentage.