RU2495009C2 - Method of producing pellet powder - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of pellet powder for small arms. After completion of the process of dispersing powder lacquer on spherical particles at mixture temperature in the reactor of 68…70°C, sodium sulphate (Na_zSO₄) is fed into the reactor in amount of 0.6…1.5 wt % with respect to water and the process of distilling the solvent is started immediately.

EFFECT: invention provides stable porosity of powder elements of pellet powder.

3 ex, 1 tbl

Description

The invention relates to the field of producing spherical powders for small arms.

US patents [1, 2] provide methods for producing spherical powders (TFP) for small arms, which include grinding fine-grained pyroxylin powders (MWP) in an aqueous medium, followed by dissolving in a solvent, dispersing powder varnish onto spherical particles and distilling off the solvent from them.

A disadvantage of the known methods is that the dehydration of spherical powders is carried out in a separate operation, where the dehydration process is carried out ~ 30 ... 40 minutes.

The closest technical solution is the method of producing spherical powders for a 5.6 mm sports cartridge [3] prototype, where the dehydration of the powder elements is allocated in a separate operation and spend it for 30 minutes at a temperature of the mixture in the reactor equal to 66 ... 70 ° C.

The authors first discovered that the process of dehydration of spherical powder elements is more intense at high temperatures, while the moisture associated physically and chemically with ethyl acetate, due to diffusion processes, passes into the dispersion medium, while ensuring uniform shrinkage of the powder elements. This, in turn, leads to a reduction in the production of spherical powder and a decrease in porosity in the powder elements.

The aim of the invention is the exclusion from the process of dehydration of spherical powder elements and ensure stable porosity of the powder elements of spherical powder.

This goal is achieved by the fact that after the dispersion of the powder varnish onto spherical particles at a temperature of the mixture in the reactor equal to 68 ... 70 ° C, sodium sulfate (Na ₂ SO ₄ ) in the amount of 0.6 ... 1.5 is introduced into the reactor with respect to water wt.% and immediately lead the process of distillation of the solvent.

Examples of the method for producing spherical powder with the exception of the operation of dehydration of the powder elements upon receipt of spherical powder for the cartridge. 30 CARBINE (7.62 × 33) within the boundary conditions (examples 1 ... 3) and outside the boundary conditions (examples 4, 5).

Example 1. 308 liters of water are poured into a reactor with a volume of 1.57 m ³ , 140 kg of nitrocellulose are loaded, 308 liters of ethyl acetate, 0.42 kg of diphenylamine and 0.14 kg of graphite or technical carbon are poured, a powder varnish is prepared with stirring for 30 minutes .

After preparation of the powder varnish, 3.08 kg of protective colloid (mesher glue) is introduced into the reactor and the powder varnish is crushed into spherical particles for 60 minutes, after which 1.85 kg of sodium sulfate are introduced at 68 ° C and at a coolant temperature of 76 ... At a temperature of 80 ° C, 65% by weight of solvent is distilled off in the reactor jacket for 60 minutes, and at a temperature of 97 ° C, the remainder of the solvent is distilled off for 20 minutes. Technological modes, physico-chemical and ballistic characteristics are given in the table.

Example 2. 364 liters of water are poured into a reactor with a volume of 1.57 m ³ , 140 kg of nitrocellulose are loaded with stirring, 364 liters of ethyl acetate, 0.525 kg of diphenylamine, 0.35 kg of graphite or technical carbon are poured, a powder varnish is prepared with stirring for 45 minutes .

After preparation of the powder varnish, 6.35 kg of coarse glue is introduced into the reactor and the powder varnish is crushed into spherical particles for 75 minutes, after which 3.82 kg of sodium sulfate are introduced at a temperature of 69 ° C and at a coolant temperature of 77 ... 82 in the jacket of the reactor ° C for 70 minutes and at a temperature of 98 ° C for 20 minutes, the solvent is distilled off. Technological modes, physico-chemical and ballistic characteristics are given in the table.

Example 3. 420 liters of water are poured into a reactor with a volume of 1.57 m ³ , 140 kg of nitrocellulose are loaded with stirring, 420 liters of ethyl acetate, 0.69 kg of diphenylamine and 0.56 kg of graphite or technical carbon are poured, a powder varnish is prepared for 60 minutes with stirring.

After preparation of the powder varnish, 10.5 kg of coarse glue is introduced into the reactor and the powder varnish is crushed into spherical particles for 90 minutes, after that, at a temperature of 70 ° C, 6.30 kg of sodium sulfate are introduced and at a coolant temperature in the reactor jacket 78 ... 84 ° C for 80 minutes and at a temperature of 99 ° C for 20 minutes, the solvent is distilled off. Technological modes, physico-chemical and ballistic characteristics are given in the table.

Table Technological modes, physico-chemical and ballistic characteristics of the manufactured samples of gunpowder Name of indicator Example (Ex. No. 1) Etc. Number 2 Etc. Number 3 Etc. Number 4 Etc. Number 5 one 2 3 four 5 6 The volume of the reactor, m ³ 1,57 1,57 1,57 1,57 1,57 Nitrocellulose loading, kg 140 140 140 140 140 The amount of water, l 308 364 420 300 425 The amount of ethyl acetate, l 308 364 420 250 480 The amount of diphenylamine, kg 0.42 0.525 0.69 0.3 0.8 The amount of graphite or carbon technical, kg 0.14 0.35 0.56 0.1 0.7 Powder varnish preparation time, min thirty 45 60 twenty 70

Table continuation one 2 3 four 5 6 The amount of protective colloid, kg 3.08 6.35 10.5 2.0 12 Powder varnish crushing time, min 60 75 90 40 one hundred Mixing time min - - - 35 35 Dehydration temperature of powder elements, ° C 68 69 70 62 70 The amount of sodium sulfate, kg 1.85 3.82 6.30 1,5 7.0 Solvent Stripping Temperature, ° C 76 77 78 74 76 The amount of distilled solvent,% 65 67 70 64 80 Solvent Stripping Temperature, ° C 80 82 84 79 85 Solvent stripping time, min 60 70 80 55 85 Solvent Stripping Temperature, ° C 97 98 99 96 99 Solvent stripping time, min twenty twenty twenty twenty twenty Bulk density, kg / dm 0.968 0.976 0.975 0.850 0.930 Chemical resistance, mmHg 25 25 25 25 25 Porosity,% 3.0 2.0 3.0 10.0 12.0 Ballistic characteristics Mass of charge, g 0.83 0.85 0.84 0.79 0.98 The average velocity of the bullet in the ballistic group, m / s 558 556 559 530 490 The difference between the largest and smallest values of the speed of the bullets, m / s 13 16 fifteen 38 40 The maximum pressure of the powder gases in the ballistic group, MPa Average 221.0 241.2 250.8 269.6 230,4 The greatest 234.1 257.8 301.0 327.5 261.8

From the table data it is seen that the powder obtained by the authors within the boundary conditions has a porosity in the range of 2.0 ... 3.0%, bulk density of 0.968 ... 0.976 kg / dm ³ , while the production cycle for producing spherical powder is reduced by 10 ... 30 minutes . According to the ballistic characteristics, the spherical powder obtained by the authors satisfies all the requirements intended for equipping sporting and hunting cartridges. 30 CARBINE (7.62 × 33).

According to technical conditions: the average flight speed of a bullet in a ballistic group is not less than 550 m / s; the difference between the largest and lowest values of the bullet’s flight speed is not more than 35 m / s, the maximum pressure of powder gases in the ballistic group, MPa: average - not more than 264.7, the largest - not more than 313.7.

Therefore, the method developed by the authors for producing spherical gunpowder for small arms allowed:

- receive spherical gunpowder with a lower uniformly distributed porosity in the powder elements and a high bulk density;

- reduce the technological cycle of obtaining TFP by eliminating the operation of dehydration of spherical particles;

- to increase the stability of ballistic characteristics in terms of bullet flight speed, the difference between the highest and lowest values of the bullet flight speed, the maximum pressure of powder gases in the ballistic group, as well as in the mass of the powder charge.

Literature

1. US patent No. 2843584.

2. US Patent No. 3378545.

3. RF patent No. 1806462 (C06B 21/00).

Claims (1)

A method for producing spherical powders, including dissolving nitrocellulose in ethyl acetate, dispersing powder varnish in a dispersed medium onto spherical particles, removing moisture from the powder elements, followed by distillation of ethyl acetate from them, characterized in that after the process of dispersing the powder varnish onto spherical particles at a mixture temperature a reactor equal to 68-70 ° C, sodium sulfate in the amount of 0.6-1.5 wt.% is introduced into the reactor and immediately the process of distillation of ethyl acetate from powder particles is carried out, first at a rate a temperature of 76-80 ° C for 60-80 minutes, then at a temperature of 97-99 ° C for 20 minutes.