JPS5818357B2 - solid propellant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double base or composite modified double base solid propellant that has good mechanical properties, particularly elongation at low temperatures.

The solid propellant is preferably one whose mechanical properties do not change in the temperature range from low to high temperatures.

However, the mechanical properties of solid propellants whose main components are nitrocellulose and nitroglycerin, i.e., double-base propellants or composite modified double-base propellants, are easily affected by changes in temperature, and their propulsion is impaired at high temperatures. The drawback is that the drug undergoes plastic flow and is brittle at low temperatures.

(Hereinafter, solid propellants will be referred to as propellants, and double base and composite modified double base propellants will be referred to as DB and CMDB propellants, respectively).

In order to improve this above-mentioned problem, research has been done to incorporate an elastic material such as polyurethane into DB or CMDB propellants using fluid balls or pace grains, resulting in good elongation at low temperatures. Propellant can now be obtained.

However, the pace grains in propellants with improved physical properties that use pace grains contain a large amount of nitroglycerin (hereinafter referred to as N/G) in their composition compared to the pace grains in conventional propellants, and as a result, during production, There were problems in production, such as nitrocellulose (hereinafter referred to as N/C) being easily dissolved, making defoaming difficult from the viewpoint of pot life.

Furthermore, if the amount of N/G is reduced to less than 50% to solve this problem, a so-called "rock-shaped" type of propellant can be produced, and only a hard and brittle propellant can be produced, and only one with extremely low elongation at low temperatures can be produced. There wasn't.

Furthermore, propellants with improved physical properties have been compositionally limited.

-For force and fluid ball propellants, when comparing the propellants before and after the physical property improvement, the pressure index in the combustion characteristics tends to be higher; Problems such as manufacturing difficulties arise when large amounts are added, and there have been expectations for a propellant with improved physical properties using pace grains.

As a result of various studies aimed at improving the shortcomings of propellants for improving physical properties using pace grains, the present inventors have developed a propellant that has good mechanical properties, especially elongation at low temperatures, with a wide range of composition. succeeded in obtaining it.

That is, the present invention is a propellant with good elongation at low temperatures over a wide composition range without reducing combustion performance, consisting of pace grains, casting agent, polyurethane and oxidizing or combustible solid particles. .

The general composition of the pace grains used in the present invention is N
/C, N/G, stabilizers, plasticizers, combustion catalysts and oxidizing agents such as ammonium perchlorate, nitramine compounds such as HMX, RDX, metal powders such as aluminum powder, and other additives are required. These are mixed with a mixed solvent such as acetone-alcohol or ether-alcohol, and the kneaded mixture is drawn, cut, and dried to obtain pace grains.

As the plasticizer, phthalate ester or triacetin is generally used.

This plasticizer can also be used in combination as a component of a casting agent for coagulating pace grains.

Combustion catalysts are added for the purpose of stabilizing the combustion of propellants or adjusting the combustion rate, and are generally made of organic acids such as stearic acid, salicylic acid, resorcinic acid, 2-ethylhexanoic acid, lead, copper, Metal salts such as tin, organic salts such as lead, copper, tin, and acids.

chemical compound is used.

Stabilizers are added to suppress the natural decomposition of N/C and N/G, and include, for example, diphenylamine, 2-nitrodiphenylamine, methylcentralit, ethylcentralit, resorcinol, and the like.

However, the composition of the pace grains is not critical to this invention.

The particle size of pace grains is 3mm in length in the maximum direction.
~0.2 is generally used, and has a cylindrical shape, a prismatic shape, etc.

Any other shape of pace grains can be used.

The casting agent used in the present invention comprises an N/G1 plasticizer and a stabilizer, and a polyol, which is a constituent of polyurethane, is added in place of the plasticizer.

Can also be done.

The solid particles used in the present invention are selected from fluid balls, oxidizing agents, nitramine compounds, rubber powders, metal powders, and other oxidizing or combustible solid particles.

Fluid balls have N/C as their main component, and N/G and stabilizers may also be added. Generally, these components are mixed and dissolved in an organic solvent such as acetate or acetone, and this mixture is soaked in water. It is stirred, pulverized, solvent removed, and dried.

Oxidizing agents and nitramine compounds are added to widely change the combustion properties of propellants; oxidizing agents include perchlorates, nitrates, etc., and nitramine compounds include, for example, HMX, nitramine, etc. RDX etc. are used.

Rubber powder is used to adjust slurry viscosity, propellant oxygen balance,
Can be added for purposes such as adjusting combustion performance,
For example, powders of acrylonitrile butadiene rubber, butyl rubber, urethane rubber, etc. are used.

Metal powder can be added for the purpose of increasing the combustion heat of the propellant or adjusting the combustion rate, and for example, powders of aluminum, zirconium, nickel, beryllium, etc. are used.

Other solid particles such as synthetic resin may be added as appropriate.

The selection of the type of these solid particles can be freely changed according to the composition of the pace grain, the composition of the binder, etc., and the desired combustion characteristics, such as smokelessness, specific impulse, combustion speed, etc. There are cases where the quantity is limited due to combustion performance, such as metal powder that has a negative effect on smokeless properties.

Inert particles can also be used as these solid particles, but they must be used within a range that does not adversely affect combustion performance.

The average particle size of small solid particles is 175 to 1/2 that of pace grains.
The particle size is preferably within the range of 0.00, and if the particle size is larger than the pace grain particle size of 115, it will have a negative effect on the elongation of the propellant, and if the particle size is smaller than 1/200, the solid particles in the gaps between the pace grains will be Additive effect disappears.

This solid pellet is 1 part by weight per 100 parts by weight of pace grains.
It is preferable to add ~100 parts by weight, and the amount added is 1
If the amount is below, the gaps between the pace grains cannot be sufficiently filled with the particles, which adversely affects the physical properties.

Further, since the propellant of the present invention is a propellant using pace grains, the effect of the pace grains is lost when the addition of solid particles exceeds 100 parts by weight due to combustion characteristics.

Therefore, the amount added is preferably 100 parts by weight or less, more preferably 70 parts by weight or less.

As the polyurethane which is one of the constituent components in the present invention, commonly used polyols and incyanates can be used.

Examples of this polyol include polyester polyols and polyether polyols having hydroxyl groups on the molecular ends and molecular chains.

'As a polyester type polyol, for example, 1.4
Examples include one or a mixture of two or more dihydric alcohols such as -butanediol, (1), 6-hexanediol, ethylene glycol, diethylene glycol, and esters of these with adipic acid.

Further, examples of polyether type polyols include polyethylene glycol and polypropylene glycol.

Furthermore, polyols in which a small amount of trivalent or higher polyhydric alcohol is added to these polyols to control the number of hydroxyl groups in the chain length can also be used.

Incyanate compounds used in combination with polyols include:
All known incyanates can be used, especially hexamethylene diisocyanate (HM-DI),
Aliphatic or alicyclic diisocyanates such as inphorone diisocyanate (IPDI) and dimethyl diisocyanate (DDI) are preferred.

Further, in order to increase the crosslinking density, a polyhydric incyanate such as triphenyl dimethylene triisocyanate can also be added.

These polyols and incyanate compounds react to form urethane bonds, and a reaction catalyst may be added to promote this reaction.

As the reaction catalyst, common catalysts commonly used in urethane reactions can be used, such as dibutyltin diacetate, dibutyltin dilaurate, iron acetylacetonate, and the like.

These urethane binders are used in the propellant in an amount of 3 to 20, preferably 8 to 15 by weight.

If the amount added is less than 3 weight particles, the effect as a polyurethane will be low, and if the amount added exceeds 20 weight particles, the combustion characteristics of the propellant will be adversely affected.

Next, the manufacturing method for obtaining the propellant of this invention will be outlined.

(Hereinafter, parts by weight are abbreviated as parts) N/C40-85 parts, N7
05-40 parts, plasticizer 0-15 parts, stabilizer 1-5 parts, combustion catalyst 4-15 parts, oxidizer 0-40 parts, nitramine 0-40 parts
N7 to 40 to 60 parts of base grain consisting of 40 parts, etc.
070-80 parts by weight, 20-30 parts of plasticizer, 1-80 parts of stabilizer
60 to 40 parts of a casting agent consisting of 5 parts and a predetermined amount of solid small particle components are charged into a mixer, mixed to form a slurry, and this slurry is added with a predetermined amount of a urethane binder consisting of polyols, incyanate, and a reaction catalyst. The slurry-like mixture is poured into a desired container such as a mold, and left at a predetermined temperature for a predetermined time to harden to obtain the desired propellant.

This above-mentioned manufacturing method shows one example, and the method of adding the urethane binder such as polyols can be changed in order to control the urethane reaction during mixing.

Further, the propellant in the present invention is formed by pouring a predetermined mixture, such as base grains, small solid particles, etc. into a mold, and casting a mixture of a casting agent, a urethane binder, a reaction catalyst, etc., as in the grain casting method. You can also.

The propellants made in this way exhibit good elongation characteristics at low temperatures over a wide composition range compared to conventional pace grains, casting agents, or propellants made of pace grains, casting agents, and polyurethane. , a propellant is obtained which exhibits an elongation of as much as 80% at -30°C.

Example □ Pace grain, casting agent, with the composition shown in Table 1 below.
Using a urethane binder and small solid particles, propellants as shown in Table 2 were manufactured by a slurry casting method.

As a result of carrying out a tensile test on this propellant, the results shown in Table 2 were obtained.

For the tensile test, a universal tensile compression tester (Model-500) manufactured by Shinko Tsushin Kogyo Co., Ltd. was used.

As can be seen from the above examples, the propellant of the present invention in which small solid particles were interposed in the gaps between pace grains was used in the comparative example (
Compared to the conventional propellants shown in Experiment Nos. 1 and 2), the elongation at low temperatures has been significantly improved, and these double-base propellants, which were conventionally considered impossible to apply in cold regions due to their low-temperature brittleness, have been improved. The effect of this method, which can be applied at low temperatures, is remarkable.

Claims (1)

Claims: 1. A solid propellant, characterized in that it consists of pace grains, a casting agent, polyurethane and oxidizing or combustible solid pellets. 2. The solid propellant according to claim 1, wherein the solid particles are one or a mixture of two or more selected from RDX, perchlorate, nitrate, metal powder, fluid ball, and rubber powder. . 3 The size of the solid particles is 11 times the particle size of the base grain.
5 to 1/200 of the solid propellant according to claim 1.