RU2441862C1 - Octogen modification method rocket technology - Google Patents

Abstract

FIELD: rocket technology.

SUBSTANCE: invention refers to the area of rocket technology, namely to the method for enhanced composite solid propellant manufacturing. The proposed octogen modification method is as follows: prepare epoxy solution E-44 in acetone, mix at the temperature of 20±5°C for 10…15 minutes and sprinkle octogen in equal doses with the epoxy and octogen/acetone ratio 1:(4..6 for 15…20 minutes three times. The octogen/epoxy weight ratio is 100: (0.3…0.5), then the solution is to be mixed for 50…60 minutes at the temperature of 20±5°C, keep until the acetone smell disappears, dry to obtain constant weight.

EFFECT: enhanced composite solid propellant.

1 dwg, 2 tbl, 1 ex

Description

The invention relates to the modification of HMX with an epoxy compound, which is capable of changing the physicomechanical characteristics of explosives (BB). Similar compounds are used as components of CPTT, BT, and gunpowder.

Currently, the most used explosive in industry is octogen, but it has a high sensitivity to mechanical stresses, which creates dangerous situations when used in formulations. It is known that CPTT with a high content of HMX have a reduced strength due to the lack of adhesion of HMX to a combustible binder. One of the possible ways to improve the strength characteristics is the use of adhesive additives, including epoxy compounds.

The use of epoxy compounds helps to ensure the technological safety of the compositions, as well as to improve the physical, mechanical and operational characteristics of SRTT.

In order to improve the strength characteristics of CPTT, a method for modifying the surface of HMX particles with a compound having good compatibility with CPTT components has been developed. This compound is epoxy resins. For the modification, the E-44 epoxy resin was selected, which is a solid compound consisting of diphenolpropane and epichlorohydrin with a molecular weight of ~ 1100 ... 2800, an epoxy group content of 3 ... 12%, and a melting point of 54 ... 56 ° C according to TU 6-10-1347 -78.

The present invention proposes a new component of CPTT in the form of HMX crystals with an E-44 epoxy resin deposited on its surface as an adhesive additive. The obtained modified octogen is intended for use in compositions with the aim of improving the strength characteristics of SRTT.

In recent years, in a number of published works, it is noted that for the formation of adhesion of HMX to an active binder containing nitroesters, it is necessary to modify the HMX surface. The modifying substance should prevent the phenomena of adsorption of liquid components on the surface of HMX, thereby ensuring its intended purpose - the article "Study of wettability of HMX powder with a modified surface by liquids" by E.A. Kukarina, AMGromova, I.S. Kononov, published in the collection " Modern problems of technical chemistry ”materials of reports of the international scientific and technical conference, 2006, Kazan.

It is also known from the literature that to regulate the ballistic characteristics of SRTT, a method of applying (modifying) heavy metal salts to an octogen is used. A number of articles by authors Stepanov RS and others, where a method for planting salts of heavy metals and organic acids on an octogen is proposed (Physics of Combustion and Explosion, 2004, v.40, No. 5, p. 89-92; 1999, v. 35, No. 3, p. 52-56 ; 2000, v. 36, No. 5, p. 74-77; 2004, v. 40, No. 5, p. 86-90). Salts - formates, oxalates, propionitrile nitramine, cupferonates are used as a coating for HMX.

The known method, which consists in the dissolution of HMX in acetone at 60-70 ° C and then adding to the acetone solution salts or ground additives in an amount of ~ 5% by weight of HMX, followed by slow evaporation of acetone, as a result, the additive is deposited on the surface of HMX crystals (Stepanov R.S. et al. Combustion and Explosion Physics, 1999, vol. 35, No. 3, pp. 52-56). The disadvantage of this method is the use of a large amount of an organic solvent, acetone, due to the low solubility of octogen in it. This method is taken by us as a prototype. It should be noted that the solubility of HMX in acetone is 2.1 g per 100 ml of acetone at 22 ° C (Orlova E.Yu. “Chemistry and technology of high explosives”, M .: Oborongid, 1960, p. 288). Based on the data on the solubility of HMX in acetone, we have that 4.8 g are required per 100 g HMX.

The technical task of the invention is to develop a method for modifying octogen with an epoxy compound, which can improve the explosive, technological and strength characteristics of SRTT.

The technical result of the invention is achieved by preparing a solution of epoxy resin E-44 in acetone, mixing at a temperature of 20 ± 5 ° C for 10 ... 15 minutes, sprinkling octogen in three doses in equal portions with a ratio of epoxy resin and octogen to acetone 1: (4 ... 6) for 15 ... 20 minutes, and the weight ratio of HMX to epoxy is 100: (0.3 ... 0.5), stirred for 50 ... 60 minutes at a temperature of 20 ± 5 ° C, kept until it disappears odorless acetone, dried to constant weight.

The essence of the proposed method for modifying octogen with epoxy resin is that E-44 resin is deposited on the surface of the octogen during the modification process at a temperature of 20 ± 5 ° C (less energy consumption), and the amount of solvent used is sharply reduced (8 ... 10 times) compared with the prototype. All this makes the process safer, reduces time and energy costs, increases the productivity of the device.

The temperature limit for planting epoxy on HMX is 20 ± 5 ° C. An increase in temperature is undesirable, since it contributes to faster distillation of acetone, which can lead to the formation of clots of epoxy resin on the surface of the HMX (experiment 5). A decrease in temperature slows down the planting process (experiment 1).

The ratio of the total amount of epoxy resin and HMX to solvent is 1: (4 ... 6), which allows to obtain a suspension, which is necessary for the process of HMX modification (experiment 2).

Mixing epoxy resin in acetone 10 ... 15 minutes is necessary to obtain a resin solution. An increase in mixing time of more than 15 minutes is undesirable, since the duration of the production cycle increases (experiment 3). Reducing the time leads to incomplete dissolution of the resin, which can lead to clumping of HMX (experiment 1).

Octogen dosage in three doses for 15 ... 20 minutes is necessary for uniform distribution of the epoxy solution on the surface of the octogen. A dosage of less than 15 minutes is undesirable, since the octogen does not have time to distribute in the solution (experiment 4), and an increase in time increases the length of the production cycle (experiment 5).

The exposure time of the octogen suspension in the epoxy resin solution is 50 ... 60 minutes. An increase in the exposure time of more than 60 minutes is not economically feasible (experiment 5), and a decrease in the exposure time can lead to incomplete planting of the resin on the octogen (experiment 1).

The given ratio of HMX to epoxy corresponds to the level of obtained characteristics that are necessary for the development of a new product in order to put it into the compositions of the developed fuels and gunpowders. Octogen modified with epoxy allows to solve the problem of its uniform distribution in the fuel, which is necessary to obtain stable characteristics of the fuel with improved properties.

An example implementation of the claimed invention

Acetone is placed in a reactor equipped with a mechanical stirrer, a thermometer, a metering funnel, and E-44 epoxy resin is sprinkled on it, stirred at 20 ± 5 ° С for 15 minutes until the resin is completely dissolved, then octogen is poured evenly through the funnel in three doses. for 20 minutes at a weight ratio of HMX to epoxy resin of 100: 0.5, mix until a homogeneous suspension is obtained and hold under uniform stirring for 60 minutes, acetone is distilled off, and the obtained modified HMX is transferred to aluminum first pan, kept at 20 ± 5 ° C until the disappearance of the odor of acetone and dried to constant weight.

The obtained octogen, modified with epoxy resin E-44, is a powder with a yellowish tint that crumbles well, does not stick together, does not clump.

The experimental results are shown in table 1, which presents the parameters of the process of planting epoxy resin on the octogen, made within the proposed invention.

As a result of the experiments carried out within the framework of the present invention, it follows that the coating is uniform, the modified octogen has good technological characteristics.

Octogen modified with epoxy resin E-44 was investigated for explosive characteristics, sensitivity of an electric spark and mechanical stresses, which are presented in table 2.

From table 2 it follows that the octogen modified with epoxy resin E-44 became less sensitive to shock (it was at a load of P = 10 kg, 50 mm, and became at P = 10 kg, 100 mm) and less sensitive to friction (it was P ₀ = 110 MPa, and it became> 300 MPa).

The proposed method for the modification of octogen with epoxy resin E-44 can be used for the preparation of CPTT fuel compositions, the manufacture of which is carried out according to existing technology. Fuels made using octogen modified with epoxy have a lower sensitivity to mechanical stress. Improving the explosive characteristics is achieved due to the uniform distribution of epoxy resin on the surface of the particles of HMX.

A new product was obtained - an octogen modified with epoxy resin, which can be used to prepare SRTT with improved properties.

This method of producing modified octogen with epoxy resin was tested at a pilot plant of FSUE NIIPM with a positive result.

Table 1 Experience number The ratio of HMX: epoxy resin, parts by weight The temperature of the dissolution of the epoxy resin, ° C The dissolution time of the epoxy resin, minutes The ratio of epoxy resin and HMX to acetone, parts by weight Octogen dosage, minutes The exposure time of the mixture with stirring, minutes Qualitative assessment of the coating (visual on an electron microscope) one 100: 0.2 10 10 1: 7 12 45 the coating is not completely uniform 2 100: 0.5 twenty fifteen 1: 5 twenty 60 completely covered 3 100: 0.4 22 twenty 1: 4 eighteen fifty uniform coverage four 100: 0.3 eighteen 8 1: 6 10 55 there are uncovered areas 5 100: 0.7 thirty 10 1: 4,5 thirty 70 there are clots of coating

table 2 Named
compounds Shock sensitivity Friction sensitivity Shock Sensitivity Sensitivity to an electric spark, mJ according to OST B 84-892-74 according to OSTV 84-894-74 at a friction speed of 520 rpm according to OST B 84-895-74 according to MT 840-83 N _about , mm at P = 10 kg lower limit, P ₀ , MPa lower limit, P ₀ , MPa Octogen m. B according to OST B 84-2515 fifty 110 250 > 100 Octogen m. In modified E-44 one hundred > 300 250 > 100

Claims (1)

A method of modifying octogen, including planting octogen in acetone, characterized in that a solution of epoxy resin E-44 in acetone is prepared, stirred at a temperature of 20 ± 5 ° C for 10-15 minutes, and octogen is sprinkled in three doses in equal portions with an epoxy ratio and octogen to acetone 1: (4-6) for 15-20 minutes, and the weight ratio of octogen to epoxy is 100: (0.3-0.5), stirred for 50-60 minutes at a temperature of 20 ± 5 ° C, maintained until the smell of acetone disappears, dried to constant weight.