JP5074686B2 - Propellant for low temperature gas generator - Google Patents

Description

  The present invention relates to a propellant for a gas generator, and more particularly to a solid propellant for a gas generator that can maintain stable combustion even at a low combustion temperature.

  The solid propellant has a simple structure with a small number of parts, is relatively easy to handle, can be stored for a long time with the propellant loaded, and has a large initial acceleration thrust. For example, it is widely used in rockets for launching medium-scale artificial satellites or rockets for weather observation. Solid propellants are roughly classified into composite solid propellants obtained by mixing an oxidant and a fuel component (binder) and double base solid propellants mainly composed of nitroglycerin and nitrocellulose.

  The composite solid propellant is a gas used for a power source such as a side thruster (for example, Patent Document 1 and Patent Document 2) for changing the course of the flying object and controlling its attitude, or a turbine and an actuator of a pressure pump. It is known to be useful as a propellant in generators. However, when used in these gas generators, provide sufficient thrust or high-pressure gas according to the desired application while burning the propellant at a low temperature from the viewpoint of the heat resistance temperature of the flying object and the device. Is required.

With respect to this point, conventionally, in order to lower the combustion temperature of the solid propellant for a gas generator, a coolant is added and the binder blending ratio is increased and adjusted. However, under such blending conditions, a pitch-like residue is generated because the binder cannot be burned completely. As a result, they are mixed in the combustion gas, adversely affecting the turbine, valves, filters and the like in the control equipment, and there is a problem that stable combustion cannot be maintained at a low combustion temperature.
JP 2001-99599 A (page 2) JP-A-9-177609 (2nd page)

  The present invention has been made in view of such circumstances, and provides a solid propellant for a gas generator that can suppress the mixing of residues in combustion gas and can maintain stable combustion even at a low combustion temperature. Is an issue.

  In the solid propellant for gas generators, the present inventors usually add a coolant to lower the combustion temperature and increase the binder content. The inventors have found that the addition of a combustion accelerator used as a catalyst can suppress a pitch-like residue generated at a low combustion temperature, thereby completing the present invention.

  That is, the present invention is a solid propellant including at least a polybutadiene polymer, ammonium perchlorate, and a coolant, the propellant further including a combustion accelerator, and the blending ratio of the polybutadiene polymer is Further, the present invention relates to a propellant for a low-temperature gas generator, characterized in that the amount is 18 to 30 parts by weight with respect to 100 parts by total of a polybutadiene-based polymer, ammonium perchlorate and a coolant.

  According to the present invention, by including a combustion accelerator in the solid propellant containing the coolant, it is possible to suppress the occurrence of pitch residue and maintain stable combustion even at a low combustion temperature. In addition, when oxalodihydroxamic acid is used as the coolant and iron oxide is used as the combustion accelerator, the above-described effect becomes greater. In addition, the above effect is further increased when the mixing ratio of the coolant and the combustion accelerator is a specific ratio.

As used herein, the term “combustion promoter” generally refers to a metal compound added in the art to improve the combustion rate. The combustion accelerator is preferably an iron oxide, for example, ferric trioxide (Fe ₂ O ₃ ) or triiron tetroxide (Fe ₃ O ₄ ) (however, it is not limited thereto). ). The blending ratio of the combustion accelerator used in the propellant for the low-temperature gas generator of the present invention is 0.1 to 1 part by weight, preferably 0. 0 parts by weight based on 100 parts of the total of the polybutadiene polymer, ammonium perchlorate and the coolant. It is 3 to 1 part by weight, and 0.3 part by weight is particularly preferable.

  As the coolant used in the propellant for a low temperature gas generator of the present invention, a coolant usually used in the art can be used, and preferably oxalodihydroxamic acid. The blending ratio of the coolant used is 75 parts by weight or less, preferably 30 to 70 parts by weight with respect to 100 parts of the total of the polybutadiene polymer, ammonium perchlorate, and the coolant. The mixing ratio of the coolant and the combustion accelerator can be used in any combination of the mixing ratios described in this specification.

  The binder component (fuel component) used in the propellant for the low temperature gas generator of the present invention can be appropriately selected from any hydrocarbon polymer or rubber material, and includes, for example, polybutadiene Polymers, polyesters, polyurethanes, polyvinyl chloride, glycidyl azide polymers and the like are included. The binder component used in the present invention is preferably a polybutadiene-based polymer, and particularly preferably terminal hydroxyl group polybutadiene (HTPB) or terminal carboxyl group polybutadiene (CTPB). The blending ratio of the binder component is 18 to 30 parts by weight, preferably 20 to 30 parts by weight, based on 100 parts of the total of the polybutadiene-based polymer, ammonium perchlorate and the coolant.

  The oxidant component used in the propellant for the low temperature gas generator of the present invention is preferably ammonium perchlorate. The compounding ratio of the oxidant component can be appropriately selected by those skilled in the art, but it is 10 to 48 with respect to 100 parts of the total of the polybutadiene-based polymer, ammonium perchlorate, and the coolant. Part by weight is preferred.

  In addition, the propellant for the low temperature gas generator of the present invention requires other additives such as a combustion rate adjusting agent, a combustion aid, a curing agent, a crosslinking agent, a binder (bonding agent), a plasticizer, and a stabilizer. It can be arbitrarily used depending on the case. Here, non-limiting examples of such burning rate modifiers may include oxamide, lithium fluoride, group 2a metal element carbonates and fluorides, and the like. Non-limiting examples of the combustion aid can include metal powders such as aluminum, magnesium, zirconium, and the like. The curing agent for the binder may be a curing agent that is usually used in the art, and examples thereof include isophorone diisocyanate and hexamethylene diisocyanate.

  According to the present invention, by adding the above combustion accelerator to the propellant for a gas generator, it is possible to achieve stable combustion by suppressing generation of pitch residue due to insufficient combustion of the binder component even at a low combustion temperature. Have Although the mechanism of the manifestation of the effect is not clear, when using a propellant having a composition with a large amount of binder component and coolant as in the past, the adiabatic flame temperature decreases and the heat input to the propellant decreases, As a result, a pitch-like residue due to insufficient combustion of the binder component occurs in exchange for a decrease in the combustion temperature, whereas in the case of the propellant of the present invention, the iron oxide or the like described in this specification By adding the combustion accelerator into the propellant, it is presumed that the decomposition start temperature of the oxidizing agent (such as ammonium perchlorate) is lowered, and the combustibility of the entire propellant is improved.

  The propellant of the present invention can be produced by using a production method used for a normal composite solid propellant in the art. For example, a necessary amount of other additives such as a curing agent is added to the binder component and mixed. Next, a combustion accelerator and an oxidizing agent are added and further mixed. Thereafter, heat curing is performed.

  The following examples further illustrate the invention.

  The typical compounding ratio of the solid propellant for gas generator in the present invention is as follows.

Ingredients by weight Polybutadiene polymer 24
Ammonium perchlorate 16
Oxalodihydroxamic acid 60
Ferric trioxide 0.3
Oxamide 5

Various propellants were produced by changing the blend ratio of the above polybutadiene polymer (binder component: HTPB) and ferric trioxide (combustion accelerator component) as shown in Table 1 (other components are constant) .

The various propellants shown in Table 1 were subjected to a strand test by the following method, and the residues generated after the test were examined.
A part of the propellant was cut into a 7 × 7 × 70 mm shape to prepare a test sample. A fuse wire was passed from one end of the sample, which was set in a pressure vessel and sealed. After pressurizing to a predetermined pressure using nitrogen gas, the sample was ignited and the amount of residue generated after complete combustion was observed. The combustion pressure used is about 7 MPa . The other conditions for the strand test are well known in the technical field and can be appropriately determined by those skilled in the art according to the experimental equipment and the like. The obtained results are shown in Table 1.

  In addition, in order to clarify the test results, as a typical example, halftone copies of photographs of the samples 1 and 3 taken after the sample combustion are shown in FIGS. In the sample 1 to which the combustion accelerator is not added, a black lump which is a residue of the binder is generated around the needle for fixing the sample (FIG. 1), whereas for the sample 3 containing the combustion accelerator, No such residue is seen (Figure 2).

  These results show that in the propellant for gas generator of the present invention, even when the binder component and the coolant are included at a high blending ratio, it is possible to suppress the occurrence of pitch residue due to insufficient combustion of the binder component. Is specified.

FIG. 1 is a halftone copy of a photograph showing the state of occurrence of residue after completion of the strand test for Sample 1 to which no combustion accelerator is added. FIG. 2 is a halftone copy of a photograph showing the state of occurrence of residue after completion of the strand test for Sample 3 containing a combustion accelerator.

Claims (2)

A solid propellant including at least a polybutadiene-based polymer, ammonium perchlorate, and a coolant, the propellant further including a combustion accelerator ;
On the sum 100 parts of Po Li butadiene polymer and ammonium perchlorate as the coolant
The blending ratio of the polybutadiene polymer is 24 to 30 parts by weight
The mixing ratio of the coolant is 75 parts by weight or less,
A propellant for a low-temperature gas generator , wherein the blending ratio of the combustion accelerator is 0.1 to 1 part by weight .
The propellant for a low-temperature gas generator according to claim 1, wherein the coolant is oxalodihydroxamic acid, and the combustion accelerator is iron oxide.

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