JPH0794359B2 - Ammonium perchlorate composite propellant - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to ammonium perchlorate composite propellants having a low pressure index.

[0002]

2. Description of the Related Art In a composite propellant containing ammonium perchlorate (hereinafter, AP) as a main component of a solid propellant, AP is used as an oxidant and a polymer is used as a reducing agent (fuel) and a binder. . Polyurethane, polybutadiene and the like are used as the polymer, but at present, terminal hydroxypolybutadiene (hereinafter referred to as HTPB) having OH groups at both ends is predominant. The combustion reaction occurs due to the redox reaction of these oxidizer and binder, and the reaction temperature thereof reaches 3000K.

The burning rate of a solid propellant is determined by the balance between the heat generated by the reaction in the vicinity of the combustion reaction surface and the reaction in the gas phase and the amount of heat returned to the solid surface. In the case of an AP composite propellant, the combustion rate is also determined by the heat balance, but the combustion reaction has a rate-determining step of the AP diffusion rate rather than the AP binder reaction rate on the combustion surface. Is strongly dependent on the concentration of AP contained in the propellant and the weight average particle size. Generally burning rate is AP
It increases as the concentration increases and as the weight average particle size decreases. Further, as a method for controlling the burning rate, there is a method using a catalyst, and in this case, it depends on the catalyst concentration and type. Iron oxide (Fe ₂ O ₃ ) is generally used as a catalyst.
Etc. are used.

The combustion rate also depends on the pressure around the propellant, since the reaction in the gas phase is involved as described above. The dependence of the burning rate on the pressure is represented by a pressure index, for example, A
In the case of P / HTPB propellant, it shows a pressure index of 0.3-0.5. The propellant pressure index has an important meaning in the design of propellant. In other words, when propellant having a high pressure index is burned, when a slight pressure fluctuation occurs in the combustion chamber, the combustion speed fluctuates greatly, resulting in unstable combustion, and stable combustion performance cannot be obtained. Further, in some cases, the combustion of the propellant may be interrupted or the motor case may be destroyed. Therefore, it is preferable that the pressure index of the propellant is as small as possible, and the propellant having a pressure index of 0 is most preferable. When the pressure index is 0, the combustion speed does not change even if the pressure fluctuates, and stable combustion performance can be obtained. Therefore, it is considered to make the pressure index of the AP composite propellant close to zero.

[0005]

In recent years, in order to increase the energy of AP composite propellants, it has been considered to use a high energy polymer as the main component of the binder. Although a number of studies have been carried out as a high energy of the binder, polyethers having azidomethyl groups such as disclosed in U.S. Patent No. 4,268,450, it is actively carried out research as high energy binder There is.

When this polyether having an azidomethyl group is used as a binder for an AP composite propellant, the energy of the propellant is higher than that of the AP / HTPB propellant. The pressure index of this polyether having AP / azidomethyl group is almost the same as that of AP / HTPB propellant.
However , as described above, the closer the pressure index is to 0, the more stable combustion characteristics can be obtained, which is very advantageous in designing the propellant. Therefore, the inventors of the present invention have earnestly studied whether the pressure index can be further lowered, and as a result, have succeeded in obtaining a propellant having a low pressure index by controlling the weight average particle diameter of AP.

[0007]

The present invention provides a composite propellant containing ammonium perchlorate as a main component, wherein the weight average particle diameter of ammonium perchlorate is 100.
It is ~ 250 μm, and the main component of the binder is a polyether having an azidomethyl group, which is an ammonium perchlorate composite propellant.

The present invention will be described below. In the present invention, AP is preferably in the range of 70 to 86% by weight of the solid propellant. When AP is less than 70% by weight, the burning rate becomes low, which is not preferable in operation. On the other hand, when AP exceeds 86% by weight, the propellant has a lower propulsive force than the AP / HTPB propellant, so that the effect of using the polyether having an azidomethyl group is reduced. Furthermore, the weight average particle diameter of AP is required to be 100 to 250 μm, which is 400 μm.
It is adjusted by mixing AP having a particle size of m, 200 μm, 35 μm, 10 μm, 5 μm in a predetermined ratio, but the weight average particle size of AP does not depend on the individual particle size of the mixed AP. is important. The adjustment of the weight average particle diameter is performed by specifically adjusting the A of 400 μm and 200 μm.
P is adjusted using a sieve and is 35μm, 10μm, 5μ
m is measured and adjusted by a subsieve sizer particle size distribution measuring device. For example, 33 parts by weight of 400 μm AP,
When 34 parts by weight of 200 μm AP and 33 parts by weight of AP having an average particle size measured by a subsieve sizer particle size distribution measuring device of 10 μm are mixed, the weight average particle size of AP is ( 400 × 33 + 200 × 34 + 10 × 33 ). / 100
= 203.3 ( μm ) .

The weight average particle diameter of AP in the propellant is 100 μ
When it is smaller than m, the pressure index becomes comparable to that of the AP / HTPB propellant, and the effect is reduced. Further, if the weight average particle diameter of AP is larger than 250 μm, the burning rate becomes low, which is not preferable in operation. A more preferable weight average particle diameter of AP is in the range of 200 to 250 μm. Azidomethylmethyl oxetane (AMMO) is one of the polyethers having an azidomethyl group as the main component of the binder.

[0010] Polyether Other U.S. Patent glycidyl azide polymer is a terminal hydroxyl group polyethers having Mechiruajido group in the side chain disclosed in No. 4,268,450 specification (GA of AMMO having the azidomethyl group
P) and bisazidomethyloxetane (BAMO), but any one having an azido group in the side chain may be used.

The propellant of the present composition has a burning velocity of a propellant, which is maintained at a constant pressure while a gas is fed from a gas cylinder having a predetermined pressure into a pressure vessel having a constant volume and the gas is caused to flow. It is measured by a chimney-type strand tester, which measures the burning rate from the burning time required for. That is, the burning rate is such that the outer peripheral surface of a cylindrical propellant having a diameter of 7 mm and a length of 70 mm is coated with an epoxy resin, and holes are formed in the side surface of the propellant at regular intervals to fuse the fuse. Pass the line. This test piece is 2
After controlling the temperature at 5 ° C for 2 hours or more, the pressure was adjusted to the range of 0.5 to 30 MPa by the chimney type strand tester, and the burning rate at each pressure was set to the distance between the fuse wires and the fire ignited on one of the fuse wires. And the time until the other fuse wire is cut. Specifically, the combustion speed (r) = ( distance between fuse wires ) / ( fuse wire disconnection time ) obtained by the following equation. The combustion speed (r) has the following relationship with the combustion pressure (p).

R = ap ⁿ where a is a constant and n is a pressure index. By the above method, the ammonium perchlorate composite propellant of the present invention can be obtained.

[0013]

The present invention will be described in detail below with reference to examples. AP which is the main component of propellant is 400μm, 200μ
having passed through a m sieve and having a size of 10 μm measured by a subsieve sizer particle size distribution measuring device, and 20
What passed through a 0 μm sieve and those having a particle size of 35 μm and 5 μm measured by a subsieve sizer particle size distribution measuring apparatus were mixed at a predetermined ratio to prepare a target weight average particle diameter. The compounding ratio of AP is shown in Table 1.

The binder is the main component AMMO100.
Relative to the weight parts, 20 parts by weight of isodecyl pelargonate (IDP) plasticizers, a curing agent isophorone diisocyanate (IPDI) and 1.0 equivalents of trimethylolpropane (TMP) is a cross-linking agent 5.0 parts by weight,
Curing catalyst dibutyltin dilaurate (DBTD
0.1 parts by weight of L) are added and mixed.

After that, the AP and the binder were mixed in a weight ratio of 8
The mixture was charged at a ratio of 0:20, vacuum mixed at 60 ° C. for 30 minutes, and then cast into a predetermined container while performing vacuum defoaming. The cast compound was cured at 60 ° C for 7 days to obtain the propellant of the present invention. This propellant was processed into a cylindrical shape with a diameter of 7 mm and a length of 70 mm according to the above method of measuring the burning rate, and its outer peripheral surface was coated with epoxy resin. Fuse wires were passed through the side surface of the propellant at regular intervals. A test piece was prepared.
After controlling the temperature of this test piece at 25 ° C. for 2 hours or more, the pressure was adjusted to a range of 0.5 to 30 MPa by a chimney-type strand tester, and the burning rate at each pressure was measured for the distance between the fuse wires and one of the fuse wires. It was determined by measuring the time until the ignited flame progressed and the other fuse wire was blown. Obtained burning velocity (m / s) and pressure (MPa)
The relationship is shown in FIG. In addition, the weight average particle size of AP (μ
The relationship between m) and the pressure index is shown in FIG.

[0016]

[Table 1]

[0017]

[Comparative Example 1] The weight average particle diameter of AP is 100 to 250 μm.
To be in the range of those of 10μm which AP is measured 400 [mu] m, which has passed through the 200μm sieve and the Sub-Sieve Sizer particle size distribution measuring apparatus, and 200μ
sieve 35μm measured by what the Sub-Sieve Sizer particle size distribution measuring apparatus which has passed through the m, respectively using those 5μm were mixed at a predetermined ratio. The compounding ratio of AP is shown in Table 2. The binder is 20 parts by weight of IDP, 1.0 equivalent of IPDI with respect to 100 parts by weight of HTPB as the main component,
TMP (5.0 parts by weight) and DBTDL (0.1 parts by weight) were added, and the mixture was prepared by the method according to the example, and the burning rate was measured by the same method. Obtained burning velocity (m / s) and pressure (M
The relationship of Pa) is shown in FIG.

In FIG. 2 showing the relationship between the pressure index of the AP / HTPB propellant and the weight average particle diameter of AP, the pressure index tends to decrease as the weight average particle diameter increases. Compared with the pressure index of AMMO composite propellant, its pressure index is 0.3-0.5.
Indicates the value of.

[0019]

[Table 2]

[0020]

Comparative Example 2 AP passed through a 200 μm sieve so that the weight average particle diameter of AP was less than 100 μm,
A propellant was prepared by a method according to the example, which was prepared by mixing with a binder having the same composition as the example in the same manner by mixing the particles having a size of 35 μm and 5 μm measured by a subsieve sizer particle size measuring device at a predetermined ratio. Then, the burning rate was measured by the same method. Table 3 shows the blending ratio of AP. Also,
The pressure index is obtained from the obtained relationship between the combustion speed (m / s) and the pressure (MPa), and the relationship between the obtained pressure index and the particle size (μm) is shown in FIG.

In FIG. 2 showing the relationship between the pressure index of AP / AMMO propellant and the weight average particle diameter of AP, when the weight average particle diameter of AP is less than 100 μm, the pressure index is AP.
/ HTPB propellant, and shows a value of about 0.5.

[0022]

[Table 3]

[0023]

INDUSTRIAL APPLICABILITY The AP / AMMO composite propellant of the present invention can easily adjust the pressure index without using a catalyst or the like, and lowers the pressure index to about one-third that of the AP / HTPB composite propellant. This is extremely effective for designing rocket motors that have stable combustion performance in a wide pressure range.

[Brief description of drawings]

FIG. 1 is a burning rate characteristic diagram of an AP / AMMO composite propellant of the present invention.

FIG. 2 is a diagram showing the relationship between the pressure index of the AP / AMMO composite propellant and the pressure index of the AP / HTPB composite propellant of the present invention and the average particle size of AP.

Claims (2)

[Claims] 1. A composite propellant containing ammonium perchlorate as a main component, wherein the weight average particle diameter of the ammonium perchlorate is 100 to 250 μm, and the main component of the binder is a polyether having an azidomethyl group. Ammonium perchlorate composite propellant characterized by: 2. The weight average particle size of ammonium perchlorate is 200 to 250 μm, and the polyether having an azidomethyl group in the main component of the binder is azidomethylmethyloxetane. Ammonium perchlorate composite propellant.